Merge branch 'main' into amber

quartz/src/main/java/com/vitorpamplona/quartz/crypto/CryptoUtils.kt

@@ -0,0 +1,260 @@
+package com.vitorpamplona.quartz.crypto
+
+import android.util.Log
+import com.goterl.lazysodium.SodiumAndroid
+import com.goterl.lazysodium.utils.Key
+import com.vitorpamplona.quartz.events.Event
+import com.vitorpamplona.quartz.encoders.Hex
+import fr.acinq.secp256k1.Secp256k1
+import java.security.MessageDigest
+import java.security.SecureRandom
+import java.util.Base64
+import javax.crypto.Cipher
+import javax.crypto.spec.IvParameterSpec
+import javax.crypto.spec.SecretKeySpec
+
+
+object CryptoUtils {
+    private val secp256k1 = Secp256k1.get()
+    private val libSodium = SodiumAndroid()
+    private val random = SecureRandom()
+    private val h02 = Hex.decode("02")
+
+    fun randomInt(bound: Int): Int {
+        return random.nextInt(bound)
+    }
+
+    /**
+     * Provides a 32B "private key" aka random number
+     */
+    fun privkeyCreate(): ByteArray {
+        val bytes = ByteArray(32)
+        random.nextBytes(bytes)
+        return bytes
+    }
+
+    fun pubkeyCreate(privKey: ByteArray) =
+        secp256k1.pubKeyCompress(secp256k1.pubkeyCreate(privKey)).copyOfRange(1, 33)
+
+    fun sign(data: ByteArray, privKey: ByteArray): ByteArray =
+        secp256k1.signSchnorr(data, privKey, null)
+
+    fun verifySignature(
+        signature: ByteArray,
+        hash: ByteArray,
+        pubKey: ByteArray
+    ): Boolean {
+        return secp256k1.verifySchnorr(signature, hash, pubKey)
+    }
+
+    fun sha256(data: ByteArray): ByteArray {
+        // Creates a new buffer every time
+        return MessageDigest.getInstance("SHA-256").digest(data)
+    }
+
+    /**
+     * @return 32B shared secret
+     */
+    fun getSharedSecretNIP04(privateKey: ByteArray, pubKey: ByteArray): ByteArray =
+        secp256k1.pubKeyTweakMul(h02 + pubKey, privateKey).copyOfRange(1, 33)
+
+    fun encryptNIP04(msg: String, privateKey: ByteArray, pubKey: ByteArray): String {
+        val info = encryptNIP04(msg, getSharedSecretNIP04(privateKey, pubKey))
+        val encryptionInfo = EncryptedInfoString(
+            v = info.v,
+            nonce = Base64.getEncoder().encodeToString(info.nonce),
+            ciphertext = Base64.getEncoder().encodeToString(info.ciphertext)
+        )
+        return "${encryptionInfo.ciphertext}?iv=${encryptionInfo.nonce}"
+    }
+
+    fun encryptNIP04Json(msg: String, privateKey: ByteArray, pubKey: ByteArray): EncryptedInfo {
+        return encryptNIP04(msg, getSharedSecretNIP04(privateKey, pubKey))
+    }
+
+    fun encryptNIP04(msg: String, sharedSecret: ByteArray): EncryptedInfo {
+        val iv = ByteArray(16)
+        random.nextBytes(iv)
+        val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
+        cipher.init(Cipher.ENCRYPT_MODE, SecretKeySpec(sharedSecret, "AES"), IvParameterSpec(iv))
+        //val ivBase64 = Base64.getEncoder().encodeToString(iv)
+        val encryptedMsg = cipher.doFinal(msg.toByteArray())
+        //val encryptedMsgBase64 = Base64.getEncoder().encodeToString(encryptedMsg)
+        return EncryptedInfo(encryptedMsg, iv, Nip44Version.NIP04.versionCode)
+    }
+
+    fun decryptNIP04(msg: String, privateKey: ByteArray, pubKey: ByteArray): String {
+        val sharedSecret = getSharedSecretNIP04(privateKey, pubKey)
+        return decryptNIP04(msg, sharedSecret)
+    }
+
+    fun decryptNIP04(encryptedInfo: EncryptedInfo, privateKey: ByteArray, pubKey: ByteArray): String {
+        val sharedSecret = getSharedSecretNIP04(privateKey, pubKey)
+        return decryptNIP04(encryptedInfo.ciphertext, encryptedInfo.nonce, sharedSecret)
+    }
+
+    fun decryptNIP04(msg: String, sharedSecret: ByteArray): String {
+        val parts = msg.split("?iv=")
+        return decryptNIP04(parts[0], parts[1], sharedSecret)
+    }
+
+    private fun decryptNIP04(cipher: String, nonce: String, sharedSecret: ByteArray): String {
+        val iv = Base64.getDecoder().decode(nonce)
+        val encryptedMsg = Base64.getDecoder().decode(cipher)
+        return decryptNIP04(encryptedMsg, iv, sharedSecret)
+    }
+
+    private fun decryptNIP04(encryptedMsg: ByteArray, iv: ByteArray, sharedSecret: ByteArray): String {
+        val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
+        cipher.init(Cipher.DECRYPT_MODE, SecretKeySpec(sharedSecret, "AES"), IvParameterSpec(iv))
+        return String(cipher.doFinal(encryptedMsg))
+    }
+
+    fun encryptNIP24(msg: String, privateKey: ByteArray, pubKey: ByteArray): EncryptedInfo {
+        val sharedSecret = getSharedSecretNIP24(privateKey, pubKey)
+        return encryptNIP24(msg, sharedSecret)
+    }
+
+    fun encryptNIP24(msg: String, sharedSecret: ByteArray): EncryptedInfo {
+        val nonce = ByteArray(24)
+        random.nextBytes(nonce)
+
+        val cipher = cryptoStreamXChaCha20Xor(
+            libSodium = libSodium,
+            messageBytes = msg.toByteArray(),//compress(msg),
+            nonce = nonce,
+            key = Key.fromBytes(sharedSecret)
+        )
+
+        return EncryptedInfo(
+            ciphertext = cipher ?: ByteArray(0),
+            nonce = nonce,
+            v = Nip44Version.NIP24.versionCode
+        )
+    }
+
+    fun decryptNIP24(encryptedInfo: EncryptedInfo, privateKey: ByteArray, pubKey: ByteArray): String? {
+        val sharedSecret = getSharedSecretNIP24(privateKey, pubKey)
+        return decryptNIP24(encryptedInfo, sharedSecret)
+    }
+
+    fun decryptNIP24(encryptedInfo: EncryptedInfo, sharedSecret: ByteArray): String? {
+        return cryptoStreamXChaCha20Xor(
+            libSodium = libSodium,
+            messageBytes = encryptedInfo.ciphertext,
+            nonce = encryptedInfo.nonce,
+            key = Key.fromBytes(sharedSecret)
+        )?.decodeToString() //?.let { decompress(it) }
+    }
+
+    /**
+     * @return 32B shared secret
+     */
+    fun getSharedSecretNIP24(privateKey: ByteArray, pubKey: ByteArray): ByteArray =
+        sha256(secp256k1.pubKeyTweakMul(h02 + pubKey, privateKey).copyOfRange(1, 33))
+}
+
+data class EncryptedInfo(val ciphertext: ByteArray, val nonce: ByteArray, val v: Int)
+data class EncryptedInfoString(val ciphertext: String, val nonce: String, val v: Int)
+
+enum class Nip44Version(val versionCode: Int) {
+    NIP04(0),
+    NIP24(1)
+}
+
+
+fun encodeNIP44(info: EncryptedInfo): String {
+    return encodeByteArray(info)
+}
+
+fun decodeNIP44(str: String): EncryptedInfo? {
+    if (str.isEmpty()) return null
+    return if (str[0] == '{') {
+        decodeJackson(str)
+    } else {
+        decodeByteArray(str)
+    }
+}
+
+fun encodeByteArray(info: EncryptedInfo): String {
+    return Base64.getEncoder().encodeToString(byteArrayOf(info.v.toByte()) + info.nonce + info.ciphertext)
+}
+
+fun decodeByteArray(base64: String): EncryptedInfo? {
+    return try {
+        val byteArray = Base64.getDecoder().decode(base64)
+        return EncryptedInfo(
+            v = byteArray[0].toInt(),
+            nonce = byteArray.copyOfRange(1, 25),
+            ciphertext = byteArray.copyOfRange(25, byteArray.size)
+        )
+    } catch (e: Exception) {
+        Log.w("CryptoUtils", "Unable to Parse encrypted payload: ${base64}")
+        null
+    }
+}
+
+fun encodeJackson(info: EncryptedInfo): String {
+    return Event.mapper.writeValueAsString(
+        EncryptedInfoString(
+        v = info.v,
+        nonce = Base64.getEncoder().encodeToString(info.nonce),
+        ciphertext = Base64.getEncoder().encodeToString(info.ciphertext)
+    )
+    )
+}
+
+fun decodeJackson(json: String): EncryptedInfo {
+    val info = Event.mapper.readValue(json, EncryptedInfoString::class.java)
+    return EncryptedInfo(
+        v = info.v,
+        nonce = Base64.getDecoder().decode(info.nonce),
+        ciphertext = Base64.getDecoder().decode(info.ciphertext)
+    )
+}
+
+/*
+OLD Versions used for the Benchmark
+
+fun encodeKotlin(info: EncryptedInfo): String {
+    return Json.encodeToString(
+        EncryptedInfoString(
+        v = info.v,
+        nonce = Base64.getEncoder().encodeToString(info.nonce),
+        ciphertext = Base64.getEncoder().encodeToString(info.ciphertext)
+    )
+    )
+}
+
+fun decodeKotlin(json: String): EncryptedInfo {
+    val info = Json.decodeFromString<EncryptedInfoString>(json)
+    return EncryptedInfo(
+        v = info.v,
+        nonce = Base64.getDecoder().decode(info.nonce),
+        ciphertext = Base64.getDecoder().decode(info.ciphertext)
+    )
+}
+
+fun encodeCSV(info: EncryptedInfo): String {
+    return "${info.v},${Base64.getEncoder().encodeToString(info.nonce)},${Base64.getEncoder().encodeToString(info.ciphertext)}"
+}
+
+fun decodeCSV(base64: String): EncryptedInfo {
+    val parts = base64.split(",")
+    return EncryptedInfo(
+        v = parts[0].toInt(),
+        nonce = Base64.getDecoder().decode(parts[1]),
+        ciphertext = Base64.getDecoder().decode(parts[2])
+    )
+}
+
+
+fun compress(input: String): ByteArray {
+    return DeflaterInputStream(input.toByteArray().inputStream()).readBytes()
+}
+
+fun decompress(inputBytes: ByteArray): String {
+    return InflaterInputStream(inputBytes.inputStream()).bufferedReader().use { it.readText() }
+}
+
+*/

quartz/src/main/java/com/vitorpamplona/quartz/crypto/KeyPair.kt

@@ -0,0 +1,34 @@
+package com.vitorpamplona.quartz.crypto
+
+import com.vitorpamplona.quartz.encoders.toHexKey
+
+class KeyPair(
+    privKey: ByteArray? = null,
+    pubKey: ByteArray? = null
+) {
+    val privKey: ByteArray?
+    val pubKey: ByteArray
+
+    init {
+        if (privKey == null) {
+            if (pubKey == null) {
+                // create new, random keys
+                this.privKey = CryptoUtils.privkeyCreate()
+                this.pubKey = CryptoUtils.pubkeyCreate(this.privKey)
+            } else {
+                // this is a read-only account
+                check(pubKey.size == 32)
+                this.privKey = null
+                this.pubKey = pubKey
+            }
+        } else {
+            // as private key is provided, ignore the public key and set keys according to private key
+            this.privKey = privKey
+            this.pubKey = CryptoUtils.pubkeyCreate(privKey)
+        }
+    }
+
+    override fun toString(): String {
+        return "KeyPair(privateKey=${privKey?.toHexKey()}, publicKey=${pubKey.toHexKey()}"
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/crypto/SodiumUtils.kt

@@ -0,0 +1,85 @@
+package com.vitorpamplona.quartz.crypto
+
+import com.goterl.lazysodium.SodiumAndroid
+import com.goterl.lazysodium.utils.Key
+
+/**
+ * I initially extended these methods from the Sodium and SodiumAndroid classes
+ * But JNI doesn't like it. There is some native method overriding bug
+ * when using Kotlin extensions
+ **/
+
+fun /*Sodium.*/crypto_stream_xchacha20_xor_ic(
+    libSodium: SodiumAndroid,
+    cipher: ByteArray,
+    message: ByteArray,
+    messageLen: Long,
+    nonce: ByteArray,
+    ic: Long,
+    key: ByteArray
+): Int {
+    /**
+     * C++ Code:
+     *
+     * unsigned char k2[crypto_core_hchacha20_OUTPUTBYTES];
+     * crypto_core_hchacha20(k2, n, k, NULL);
+     * return crypto_stream_chacha20_xor_ic(
+     * c, m, mlen, n + crypto_core_hchacha20_INPUTBYTES, ic, k2);
+     */
+    val k2 = ByteArray(32)
+
+    val nonceChaCha = nonce.drop(16).toByteArray()
+    assert(nonceChaCha.size == 8)
+
+    libSodium.crypto_core_hchacha20(k2, nonce, key, null)
+    return libSodium.crypto_stream_chacha20_xor_ic(
+        cipher,
+        message,
+        messageLen,
+        nonceChaCha,
+        ic,
+        k2
+    )
+}
+
+fun /*Sodium.*/crypto_stream_xchacha20_xor(
+    libSodium: SodiumAndroid,
+    cipher: ByteArray,
+    message: ByteArray,
+    messageLen: Long,
+    nonce: ByteArray,
+    key: ByteArray
+): Int {
+    return crypto_stream_xchacha20_xor_ic(libSodium, cipher, message, messageLen, nonce, 0, key)
+}
+
+fun /*SodiumAndroid.*/cryptoStreamXChaCha20Xor(
+    libSodium: SodiumAndroid,
+    cipher: ByteArray,
+    message: ByteArray,
+    messageLen: Long,
+    nonce: ByteArray,
+    key: ByteArray
+): Boolean {
+    require(!(messageLen < 0 || messageLen > message.size)) { "messageLen out of bounds: $messageLen" }
+    return crypto_stream_xchacha20_xor(
+        libSodium,
+        cipher,
+        message,
+        messageLen,
+        nonce,
+        key
+    ) == 0
+}
+
+fun /*SodiumAndroid.*/cryptoStreamXChaCha20Xor(
+    libSodium: SodiumAndroid,
+    messageBytes: ByteArray,
+    nonce: ByteArray,
+    key: Key
+): ByteArray? {
+    val mLen = messageBytes.size
+    val cipher = ByteArray(mLen)
+    val sucessful = cryptoStreamXChaCha20Xor(libSodium, cipher, messageBytes, mLen.toLong(), nonce, key.asBytes)
+    return if (sucessful) cipher else null
+}

quartz/src/main/java/com/vitorpamplona/quartz/encoders/ATag.kt

@@ -0,0 +1,68 @@
+package com.vitorpamplona.quartz.encoders
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.encoders.Hex
+
+@Immutable
+data class ATag(val kind: Int, val pubKeyHex: String, val dTag: String, val relay: String?) {
+    fun toTag() = "$kind:$pubKeyHex:$dTag"
+
+    fun toNAddr(): String {
+        return TlvBuilder().apply {
+            addString(Nip19.TlvTypes.SPECIAL, dTag)
+            addStringIfNotNull(Nip19.TlvTypes.RELAY, relay)
+            addHex(Nip19.TlvTypes.AUTHOR, pubKeyHex)
+            addInt(Nip19.TlvTypes.KIND, kind)
+        }.build().toNAddress()
+    }
+
+    companion object {
+        fun isATag(key: String): Boolean {
+            return key.startsWith("naddr1") || key.contains(":")
+        }
+
+        fun parse(address: String, relay: String?): ATag? {
+            return if (address.startsWith("naddr") || address.startsWith("nostr:naddr")) {
+                parseNAddr(address)
+            } else {
+                parseAtag(address, relay)
+            }
+        }
+
+        fun parseAtag(atag: String, relay: String?): ATag? {
+            return try {
+                val parts = atag.split(":")
+                Hex.decode(parts[1])
+                ATag(parts[0].toInt(), parts[1], parts[2], relay)
+            } catch (t: Throwable) {
+                Log.w("ATag", "Error parsing A Tag: $atag: ${t.message}")
+                null
+            }
+        }
+
+        fun parseNAddr(naddr: String): ATag? {
+            try {
+                val key = naddr.removePrefix("nostr:")
+
+                if (key.startsWith("naddr")) {
+                    val tlv = Tlv.parse(key.bechToBytes())
+
+                    val d = tlv.firstAsString(Nip19.TlvTypes.SPECIAL) ?: ""
+                    val relay = tlv.firstAsString(Nip19.TlvTypes.RELAY)
+                    val author = tlv.firstAsHex(Nip19.TlvTypes.AUTHOR)
+                    val kind = tlv.firstAsInt(Nip19.TlvTypes.KIND)
+
+                    if (kind != null && author != null) {
+                        return ATag(kind, author, d, relay)
+                    }
+                }
+            } catch (e: Throwable) {
+                Log.w("ATag", "Issue trying to Decode NIP19 $this: ${e.message}")
+                // e.printStackTrace()
+            }
+
+            return null
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/encoders/Bech32Util.kt

@@ -0,0 +1,217 @@
+package com.vitorpamplona.quartz.encoders
+
+/*
+ * Copyright 2020 ACINQ SAS
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import kotlin.jvm.JvmStatic
+
+/**
+ * Bech32 works with 5 bits values, we use this type to make it explicit: whenever you see Int5 it means 5 bits values,
+ * and whenever you see Byte it means 8 bits values.
+ */
+private typealias Int5 = Byte
+
+/**
+ * Bech32 and Bech32m address formats.
+ * See https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki and https://github.com/bitcoin/bips/blob/master/bip-0350.mediawiki.
+ */
+object Bech32 {
+    const val alphabet: String = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
+
+    enum class Encoding(public val constant: Int) {
+        Bech32(1),
+        Bech32m(0x2bc830a3),
+        Beck32WithoutChecksum(0)
+    }
+
+    // char -> 5 bits value
+    private val map = Array<Int5>(255) { -1 }
+
+    init {
+        for (i in 0..alphabet.lastIndex) {
+            map[alphabet[i].code] = i.toByte()
+        }
+    }
+
+    private fun expand(hrp: String): Array<Int5> {
+        val result = Array<Int5>(hrp.length + 1 + hrp.length) { 0 }
+        for (i in hrp.indices) {
+            result[i] = hrp[i].code.shr(5).toByte()
+            result[hrp.length + 1 + i] = (hrp[i].code and 31).toByte()
+        }
+        result[hrp.length] = 0
+        return result
+    }
+
+    private fun polymod(values: Array<Int5>, values1: Array<Int5>): Int {
+        val GEN = arrayOf(0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3)
+        var chk = 1
+        values.forEach { v ->
+            val b = chk shr 25
+            chk = ((chk and 0x1ffffff) shl 5) xor v.toInt()
+            for (i in 0..5) {
+                if (((b shr i) and 1) != 0) chk = chk xor GEN[i]
+            }
+        }
+        values1.forEach { v ->
+            val b = chk shr 25
+            chk = ((chk and 0x1ffffff) shl 5) xor v.toInt()
+            for (i in 0..5) {
+                if (((b shr i) and 1) != 0) chk = chk xor GEN[i]
+            }
+        }
+        return chk
+    }
+
+    /**
+     * @param hrp human readable prefix
+     * @param int5s 5-bit data
+     * @param encoding encoding to use (bech32 or bech32m)
+     * @return hrp + data encoded as a Bech32 string
+     */
+    @JvmStatic
+    public fun encode(hrp: String, int5s: Array<Int5>, encoding: Encoding): String {
+        require(hrp.lowercase() == hrp || hrp.uppercase() == hrp) { "mixed case strings are not valid bech32 prefixes" }
+        val data = int5s.toByteArray().toTypedArray()
+        val checksum = when (encoding) {
+            Encoding.Beck32WithoutChecksum -> arrayOf()
+            else -> checksum(hrp, data, encoding)
+        }
+        return hrp + "1" + (data + checksum).map { i -> alphabet[i.toInt()] }.toCharArray().concatToString()
+    }
+
+    /**
+     * @param hrp human readable prefix
+     * @param data data to encode
+     * @param encoding encoding to use (bech32 or bech32m)
+     * @return hrp + data encoded as a Bech32 string
+     */
+    @JvmStatic
+    public fun encodeBytes(hrp: String, data: ByteArray, encoding: Encoding): String = encode(hrp, eight2five(data), encoding)
+
+    /**
+     * decodes a bech32 string
+     * @param bech32 bech32 string
+     * @param noChecksum if true, the bech32 string doesn't have a checksum
+     * @return a (hrp, data, encoding) tuple
+     */
+    @JvmStatic
+    public fun decode(bech32: String, noChecksum: Boolean = false): Triple<String, Array<Int5>, Encoding> {
+        require(bech32.lowercase() == bech32 || bech32.uppercase() == bech32) { "mixed case strings are not valid bech32" }
+        bech32.forEach { require(it.code in 33..126) { "invalid character " } }
+        val input = bech32.lowercase()
+        val pos = input.lastIndexOf('1')
+        val hrp = input.take(pos)
+        require(hrp.length in 1..83) { "hrp must contain 1 to 83 characters" }
+        val data = Array<Int5>(input.length - pos - 1) { 0 }
+        for (i in 0..data.lastIndex) data[i] = map[input[pos + 1 + i].code]
+        return if (noChecksum) {
+            Triple(hrp, data, Encoding.Beck32WithoutChecksum)
+        } else {
+            val encoding = when (polymod(expand(hrp), data)) {
+                Encoding.Bech32.constant -> Encoding.Bech32
+                Encoding.Bech32m.constant -> Encoding.Bech32m
+                else -> throw IllegalArgumentException("invalid checksum for $bech32")
+            }
+            Triple(hrp, data.dropLast(6).toTypedArray(), encoding)
+        }
+    }
+
+    /**
+     * decodes a bech32 string
+     * @param bech32 bech32 string
+     * @param noChecksum if true, the bech32 string doesn't have a checksum
+     * @return a (hrp, data, encoding) tuple
+     */
+    @JvmStatic
+    public fun decodeBytes(bech32: String, noChecksum: Boolean = false): Triple<String, ByteArray, Encoding> {
+        val (hrp, int5s, encoding) = decode(bech32, noChecksum)
+        return Triple(hrp, five2eight(int5s, 0), encoding)
+    }
+
+    /**
+     * @param hrp Human Readable Part
+     * @param data data (a sequence of 5 bits integers)
+     * @param encoding encoding to use (bech32 or bech32m)
+     * @return a checksum computed over hrp and data
+     */
+    private fun checksum(hrp: String, data: Array<Int5>, encoding: Encoding): Array<Int5> {
+        val values = expand(hrp) + data
+        val poly = polymod(values, arrayOf(0.toByte(), 0.toByte(), 0.toByte(), 0.toByte(), 0.toByte(), 0.toByte())) xor encoding.constant
+        return Array(6) { i -> (poly.shr(5 * (5 - i)) and 31).toByte() }
+    }
+
+    /**
+     * @param input a sequence of 8 bits integers
+     * @return a sequence of 5 bits integers
+     */
+    @JvmStatic
+    public fun eight2five(input: ByteArray): Array<Int5> {
+        var buffer = 0L
+        val output = ArrayList<Int5>()
+        var count = 0
+        input.forEach { b ->
+            buffer = (buffer shl 8) or (b.toLong() and 0xff)
+            count += 8
+            while (count >= 5) {
+                output.add(((buffer shr (count - 5)) and 31).toByte())
+                count -= 5
+            }
+        }
+        if (count > 0) output.add(((buffer shl (5 - count)) and 31).toByte())
+        return output.toTypedArray()
+    }
+
+    /**
+     * @param input a sequence of 5 bits integers
+     * @return a sequence of 8 bits integers
+     */
+    @JvmStatic
+    public fun five2eight(input: Array<Int5>, offset: Int): ByteArray {
+        var buffer = 0L
+        val output = ArrayList<Byte>()
+        var count = 0
+        for (i in offset..input.lastIndex) {
+            val b = input[i]
+            buffer = (buffer shl 5) or (b.toLong() and 31)
+            count += 5
+            while (count >= 8) {
+                output.add(((buffer shr (count - 8)) and 0xff).toByte())
+                count -= 8
+            }
+        }
+        require(count <= 4) { "Zero-padding of more than 4 bits" }
+        require((buffer and ((1L shl count) - 1L)) == 0L) { "Non-zero padding in 8-to-5 conversion" }
+        return output.toByteArray()
+    }
+}
+
+fun ByteArray.toNsec() = Bech32.encodeBytes(hrp = "nsec", this, Bech32.Encoding.Bech32)
+fun ByteArray.toNpub() = Bech32.encodeBytes(hrp = "npub", this, Bech32.Encoding.Bech32)
+fun ByteArray.toNote() = Bech32.encodeBytes(hrp = "note", this, Bech32.Encoding.Bech32)
+fun ByteArray.toNEvent() = Bech32.encodeBytes(hrp = "nevent", this, Bech32.Encoding.Bech32)
+fun ByteArray.toNAddress() = Bech32.encodeBytes(hrp = "naddr", this, Bech32.Encoding.Bech32)
+fun ByteArray.toLnUrl() = Bech32.encodeBytes(hrp = "lnurl", this, Bech32.Encoding.Bech32)
+
+fun String.bechToBytes(hrp: String? = null): ByteArray {
+    val decodedForm = Bech32.decodeBytes(this)
+    hrp?.also {
+        if (it != decodedForm.first) {
+            throw IllegalArgumentException("Expected $it but obtained ${decodedForm.first}")
+        }
+    }
+    return decodedForm.second
+}

quartz/src/main/java/com/vitorpamplona/quartz/encoders/HexUtils.kt

@@ -0,0 +1,70 @@
+package com.vitorpamplona.quartz.encoders
+
+/** Makes the distinction between String and Hex **/
+typealias HexKey = String
+
+fun ByteArray.toHexKey(): HexKey {
+    return Hex.encode(this)
+}
+
+fun HexKey.hexToByteArray(): ByteArray {
+    return Hex.decode(this)
+}
+
+object HexValidator {
+    private fun isHex2(c: Char): Boolean {
+        return when (c) {
+            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'A', 'B', 'C', 'D', 'E', 'F', ' ' -> true
+            else -> false
+        }
+    }
+
+    fun isHex(hex: String?): Boolean {
+        if (hex == null) return false
+        var isHex = true
+        for (c in hex.toCharArray()) {
+            if (!isHex2(c)) {
+                isHex = false
+                break
+            }
+        }
+        return isHex
+    }
+}
+
+object Hex {
+    private val hexCode = arrayOf('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f')
+
+    // Faster if no calculations are needed.
+    private fun hexToBin(ch: Char): Int = when (ch) {
+        in '0'..'9' -> ch - '0'
+        in 'a'..'f' -> ch - 'a' + 10
+        in 'A'..'F' -> ch - 'A' + 10
+        else -> throw IllegalArgumentException("illegal hex character: $ch")
+    }
+
+    @JvmStatic
+    fun decode(hex: String): ByteArray {
+        // faster version of hex decoder
+        require(hex.length % 2 == 0)
+        val outSize = hex.length / 2
+        val out = ByteArray(outSize)
+
+        for (i in 0 until outSize) {
+            out[i] = (hexToBin(hex[2 * i]) * 16 + hexToBin(hex[2 * i + 1])).toByte()
+        }
+
+        return out
+    }
+
+    @JvmStatic
+    fun encode(input: ByteArray): String {
+        val len = input.size
+        val out = CharArray(len * 2)
+        for (i in 0 until len) {
+            out[i*2] = hexCode[(input[i].toInt() shr 4) and 0xF]
+            out[i*2+1] = hexCode[input[i].toInt() and 0xF]
+        }
+        return String(out)
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/encoders/LnInvoiceUtil.kt

@@ -0,0 +1,173 @@
+package com.vitorpamplona.quartz.encoders
+
+import java.math.BigDecimal
+import java.util.Locale
+import java.util.regex.Pattern
+
+/** based on litecoinj */
+object LnInvoiceUtil {
+    private val invoicePattern = Pattern.compile("lnbc((?<amount>\\d+)(?<multiplier>[munp])?)?1[^1\\s]+", Pattern.CASE_INSENSITIVE)
+
+    /** The Bech32 character set for encoding.  */
+    private const val CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
+
+    /** The Bech32 character set for decoding.  */
+    private val CHARSET_REV = byteArrayOf(
+        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+        15, -1, 10, 17, 21, 20, 26, 30, 7, 5, -1, -1, -1, -1, -1, -1,
+        -1, 29, -1, 24, 13, 25, 9, 8, 23, -1, 18, 22, 31, 27, 19, -1,
+        1, 0, 3, 16, 11, 28, 12, 14, 6, 4, 2, -1, -1, -1, -1, -1,
+        -1, 29, -1, 24, 13, 25, 9, 8, 23, -1, 18, 22, 31, 27, 19, -1,
+        1, 0, 3, 16, 11, 28, 12, 14, 6, 4, 2, -1, -1, -1, -1, -1
+    )
+
+    /** Find the polynomial with value coefficients mod the generator as 30-bit.  */
+    private fun polymod(values: ByteArray): Int {
+        var c = 1
+        for (v_i in values) {
+            val c0 = c ushr 25 and 0xff
+            c = c and 0x1ffffff shl 5 xor (v_i.toInt() and 0xff)
+            if (c0 and 1 != 0) c = c xor 0x3b6a57b2
+            if (c0 and 2 != 0) c = c xor 0x26508e6d
+            if (c0 and 4 != 0) c = c xor 0x1ea119fa
+            if (c0 and 8 != 0) c = c xor 0x3d4233dd
+            if (c0 and 16 != 0) c = c xor 0x2a1462b3
+        }
+        return c
+    }
+
+    /** Expand a HRP for use in checksum computation.  */
+    private fun expandHrp(hrp: String): ByteArray {
+        val hrpLength = hrp.length
+        val ret = ByteArray(hrpLength * 2 + 1)
+        for (i in 0 until hrpLength) {
+            val c = hrp[i].code and 0x7f // Limit to standard 7-bit ASCII
+            ret[i] = (c ushr 5 and 0x07).toByte()
+            ret[i + hrpLength + 1] = (c and 0x1f).toByte()
+        }
+        ret[hrpLength] = 0
+        return ret
+    }
+
+    /** Verify a checksum.  */
+    private fun verifyChecksum(hrp: String, values: ByteArray): Boolean {
+        val hrpExpanded: ByteArray = expandHrp(hrp)
+        val combined = ByteArray(hrpExpanded.size + values.size)
+        System.arraycopy(hrpExpanded, 0, combined, 0, hrpExpanded.size)
+        System.arraycopy(values, 0, combined, hrpExpanded.size, values.size)
+        return polymod(combined) == 1
+    }
+
+    class AddressFormatException(message: String) : Exception(message)
+
+    fun decodeUnlimitedLength(invoice: String): Boolean {
+        var lower = false
+        var upper = false
+        for (i in 0 until invoice.length) {
+            val c = invoice[i]
+            if (c.code < 33 || c.code > 126) throw AddressFormatException("Invalid character: $c, pos: $i")
+            if (c in 'a'..'z') {
+                if (upper) throw AddressFormatException("Invalid character: $c, pos: $i")
+                lower = true
+            }
+            if (c in 'A'..'Z') {
+                if (lower) throw AddressFormatException("Invalid character: $c, pos: $i")
+                upper = true
+            }
+        }
+        val pos = invoice.lastIndexOf('1')
+        if (pos < 1) throw AddressFormatException("Missing human-readable part")
+        val dataPartLength = invoice.length - 1 - pos
+        if (dataPartLength < 6) throw AddressFormatException("Data part too short: $dataPartLength")
+        val values = ByteArray(dataPartLength)
+        for (i in 0 until dataPartLength) {
+            val c = invoice[i + pos + 1]
+            if (CHARSET_REV.get(c.code).toInt() == -1) throw AddressFormatException("Invalid character: " + c + ", pos: " + (i + pos + 1))
+            values[i] = CHARSET_REV.get(c.code)
+        }
+        val hrp = invoice.substring(0, pos).lowercase(Locale.ROOT)
+        if (!verifyChecksum(hrp, values)) throw AddressFormatException("Invalid Checksum")
+        return true
+    }
+
+    /**
+     * Parses invoice amount according to
+     * https://github.com/lightningnetwork/lightning-rfc/blob/master/11-payment-encoding.md#human-readable-part
+     * @return invoice amount in bitcoins, zero if the invoice has no amount
+     * @throws RuntimeException if invoice format is incorrect
+     */
+    private fun getAmount(invoice: String): BigDecimal {
+        try {
+            decodeUnlimitedLength(invoice) // checksum must match
+        } catch (e: AddressFormatException) {
+            throw IllegalArgumentException("Cannot decode invoice: $invoice", e)
+        }
+
+        val matcher = invoicePattern.matcher(invoice)
+        require(matcher.matches()) { "Failed to match HRP pattern" }
+        val amountGroup = matcher.group("amount")
+        val multiplierGroup = matcher.group("multiplier")
+        if (amountGroup == null) {
+            return BigDecimal.ZERO
+        }
+        val amount = BigDecimal(amountGroup)
+        if (multiplierGroup == null) {
+            return amount
+        }
+        require(!(multiplierGroup == "p" && amountGroup[amountGroup.length - 1] != '0')) { "sub-millisatoshi amount" }
+        return amount.multiply(multiplier(multiplierGroup))
+    }
+
+    fun getAmountInSats(invoice: String): BigDecimal {
+        return getAmount(invoice).multiply(BigDecimal(100000000))
+    }
+
+    private fun multiplier(multiplier: String): BigDecimal {
+        return when (multiplier.lowercase()) {
+            "m" -> BigDecimal("0.001")
+            "u" -> BigDecimal("0.000001")
+            "n" -> BigDecimal("0.000000001")
+            "p" -> BigDecimal("0.000000000001")
+            else -> throw IllegalArgumentException("Invalid multiplier: $multiplier")
+        }
+    }
+
+    /**
+     * Finds LN invoice in the provided input string and returns it.
+     * For example for input = "aaa bbb lnbc1xxx ccc" it will return "lnbc1xxx"
+     * It will only return the first invoice found in the input.
+     *
+     * @return the invoice if it was found. null for null input or if no invoice is found
+     */
+    fun findInvoice(input: String?): String? {
+        if (input == null) {
+            return null
+        }
+        val matcher = invoicePattern.matcher(input)
+        return if (matcher.find()) {
+            matcher.group()
+        } else {
+            null
+        }
+    }
+
+    /**
+     * If the string contains an LN invoice, returns a Pair of the start and end
+     * positions of the invoice in the string. Otherwise, returns (0, 0). This is
+     * used to ensure we don't accidentally cut an invoice in the middle when taking
+     * only a portion of the available text.
+     */
+    fun locateInvoice(input: String?): Pair<Int, Int> {
+        if (input == null) {
+            return Pair(0, 0)
+        }
+        val matcher = invoicePattern.matcher(input)
+        return if (matcher.find()) {
+            Pair(matcher.start(), matcher.end())
+        } else {
+            Pair(0, 0)
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/encoders/LnWithdrawalUtil.kt

@@ -0,0 +1,29 @@
+package com.vitorpamplona.quartz.encoders
+
+import java.util.regex.Pattern
+
+object LnWithdrawalUtil {
+    private val withdrawalPattern = Pattern.compile(
+        "lnurl.+",
+        Pattern.CASE_INSENSITIVE
+    )
+
+    /**
+     * Finds LN withdrawal in the provided input string and returns it.
+     * For example for input = "aaa bbb lnbc1xxx ccc" it will return "lnbc1xxx"
+     * It will only return the first withdrawal found in the input.
+     *
+     * @return the invoice if it was found. null for null input or if no invoice is found
+     */
+    fun findWithdrawal(input: String?): String? {
+        if (input == null) {
+            return null
+        }
+        val matcher = withdrawalPattern.matcher(input)
+        return if (matcher.find()) {
+            matcher.group()
+        } else {
+            null
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/encoders/Nip19.kt

@@ -0,0 +1,178 @@
+package com.vitorpamplona.quartz.encoders
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.crypto.KeyPair
+import com.vitorpamplona.quartz.encoders.Hex
+import java.util.regex.Pattern
+
+object Nip19 {
+    enum class Type {
+        USER, NOTE, EVENT, RELAY, ADDRESS
+    }
+
+    enum class TlvTypes(val id: Byte) {
+        SPECIAL(0),
+        RELAY(1),
+        AUTHOR(2),
+        KIND(3);
+    }
+
+    val nip19regex = Pattern.compile(
+        "(nostr:)?@?(nsec1|npub1|nevent1|naddr1|note1|nprofile1|nrelay1)([qpzry9x8gf2tvdw0s3jn54khce6mua7l]+)([\\S]*)",
+        Pattern.CASE_INSENSITIVE
+    )
+
+    @Immutable
+    data class Return(
+        val type: Type,
+        val hex: String,
+        val relay: String? = null,
+        val author: String? = null,
+        val kind: Int? = null,
+        val additionalChars: String = ""
+    )
+
+    fun uriToRoute(uri: String?): Return? {
+        if (uri == null) return null
+
+        try {
+            val matcher = nip19regex.matcher(uri)
+            if (!matcher.find()) {
+                return null
+            }
+
+            val uriScheme = matcher.group(1) // nostr:
+            val type = matcher.group(2) // npub1
+            val key = matcher.group(3) // bech32
+            val additionalChars = matcher.group(4) // additional chars
+
+            return parseComponents(uriScheme, type, key, additionalChars)
+        } catch (e: Throwable) {
+            Log.e("NIP19 Parser", "Issue trying to Decode NIP19 $uri: ${e.message}", e)
+        }
+
+        return null
+    }
+
+    fun parseComponents(
+        uriScheme: String?,
+        type: String,
+        key: String?,
+        additionalChars: String?
+    ): Return? {
+        return try {
+            val bytes = (type + key).bechToBytes()
+            val parsed = when (type.lowercase()) {
+                "npub1" -> npub(bytes)
+                "note1" -> note(bytes)
+                "nprofile1" -> nprofile(bytes)
+                "nevent1" -> nevent(bytes)
+                "nrelay1" -> nrelay(bytes)
+                "naddr1" -> naddr(bytes)
+                else -> null
+            }
+            parsed?.copy(additionalChars = additionalChars ?: "")
+        } catch (e: Throwable) {
+            Log.w("NIP19 Parser", "Issue trying to Decode NIP19 $key: ${e.message}", e)
+            null
+        }
+    }
+
+    private fun npub(bytes: ByteArray): Return {
+        return Return(Type.USER, bytes.toHexKey())
+    }
+
+    private fun note(bytes: ByteArray): Return {
+        return Return(Type.NOTE, bytes.toHexKey())
+    }
+
+    private fun nprofile(bytes: ByteArray): Return? {
+        val tlv = Tlv.parse(bytes)
+
+        val hex = tlv.firstAsHex(TlvTypes.SPECIAL) ?: return null
+        val relay = tlv.firstAsString(TlvTypes.RELAY)
+
+        return Return(Type.USER, hex, relay)
+    }
+
+    private fun nevent(bytes: ByteArray): Return? {
+        val tlv = Tlv.parse(bytes)
+
+        val hex = tlv.firstAsHex(TlvTypes.SPECIAL) ?: return null
+        val relay = tlv.firstAsString(TlvTypes.RELAY)
+        val author = tlv.firstAsHex(TlvTypes.AUTHOR)
+        val kind = tlv.firstAsInt(TlvTypes.KIND.id)
+
+        return Return(Type.EVENT, hex, relay, author, kind)
+    }
+
+    private fun nrelay(bytes: ByteArray): Return? {
+        val relayUrl = Tlv.parse(bytes).firstAsString(TlvTypes.SPECIAL.id) ?: return null
+
+        return Return(Type.RELAY, relayUrl)
+    }
+
+    private fun naddr(bytes: ByteArray): Return? {
+        val tlv = Tlv.parse(bytes)
+
+        val d = tlv.firstAsString(TlvTypes.SPECIAL.id) ?: ""
+        val relay = tlv.firstAsString(TlvTypes.RELAY.id)
+        val author = tlv.firstAsHex(TlvTypes.AUTHOR.id) ?: return null
+        val kind = tlv.firstAsInt(TlvTypes.KIND.id) ?: return null
+
+        return Return(Type.ADDRESS, "$kind:$author:$d", relay, author, kind)
+    }
+
+    public fun createNEvent(idHex: String, author: String?, kind: Int?, relay: String?): String {
+        return TlvBuilder().apply {
+            addHex(TlvTypes.SPECIAL, idHex)
+            addStringIfNotNull(TlvTypes.RELAY, relay)
+            addHexIfNotNull(TlvTypes.AUTHOR, author)
+            addIntIfNotNull(TlvTypes.KIND, kind)
+        }.build().toNEvent()
+    }
+}
+
+fun decodePublicKey(key: String): ByteArray {
+    val parsed = Nip19.uriToRoute(key)
+    val pubKeyParsed = parsed?.hex?.hexToByteArray()
+
+    return if (key.startsWith("nsec")) {
+        KeyPair(privKey = key.bechToBytes()).pubKey
+    } else if (pubKeyParsed != null) {
+        pubKeyParsed
+    } else {
+        Hex.decode(key)
+    }
+}
+
+fun decodePublicKeyAsHexOrNull(key: String): HexKey? {
+    return try {
+        val parsed = Nip19.uriToRoute(key)
+        val pubKeyParsed = parsed?.hex
+
+        if (key.startsWith("nsec")) {
+            KeyPair(privKey = key.bechToBytes()).pubKey.toHexKey()
+        } else if (pubKeyParsed != null) {
+            pubKeyParsed
+        } else {
+            Hex.decode(key).toHexKey()
+        }
+    } catch (e: Exception) {
+        null
+    }
+}
+
+
+fun TlvBuilder.addString(type: Nip19.TlvTypes, string: String) = addString(type.id, string)
+fun TlvBuilder.addHex(type: Nip19.TlvTypes, key: HexKey) = addHex(type.id, key)
+fun TlvBuilder.addInt(type: Nip19.TlvTypes, data: Int) = addInt(type.id, data)
+
+fun TlvBuilder.addStringIfNotNull(type: Nip19.TlvTypes, data: String?) = addStringIfNotNull(type.id, data)
+fun TlvBuilder.addHexIfNotNull(type: Nip19.TlvTypes, data: HexKey?) = addHexIfNotNull(type.id, data)
+fun TlvBuilder.addIntIfNotNull(type: Nip19.TlvTypes, data: Int?) = addIntIfNotNull(type.id, data)
+
+fun Tlv.firstAsInt(type: Nip19.TlvTypes) = firstAsInt(type.id)
+fun Tlv.firstAsHex(type: Nip19.TlvTypes) = firstAsHex(type.id)
+fun Tlv.firstAsString(type: Nip19.TlvTypes) = firstAsString(type.id)

quartz/src/main/java/com/vitorpamplona/quartz/encoders/Tlv.kt

@@ -0,0 +1,69 @@
+package com.vitorpamplona.quartz.encoders
+
+import java.io.ByteArrayOutputStream
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+
+class TlvBuilder() {
+    val outputStream = ByteArrayOutputStream()
+
+    private fun add(type: Byte, byteArray: ByteArray) {
+        outputStream.write(byteArrayOf(type, byteArray.size.toByte()))
+        outputStream.write(byteArray)
+    }
+
+    fun addString(type: Byte, string: String) = add(type, string.toByteArray(Charsets.UTF_8))
+    fun addHex(type: Byte, key: HexKey) = add(type, key.hexToByteArray())
+    fun addInt(type: Byte, data: Int) = add(type, data.to32BitByteArray())
+
+    fun addStringIfNotNull(type: Byte, data: String?) = data?.let { addString(type, it) }
+    fun addHexIfNotNull(type: Byte, data: HexKey?) = data?.let { addHex(type, it) }
+    fun addIntIfNotNull(type: Byte, data: Int?) = data?.let { addInt(type, it) }
+
+    fun build(): ByteArray {
+        return outputStream.toByteArray()
+    }
+}
+
+fun Int.to32BitByteArray(): ByteArray {
+    val bytes = ByteArray(4)
+    (0..3).forEach {
+        bytes[3 - it] = ((this ushr (8 * it)) and 0xFFFF).toByte()
+    }
+    return bytes
+}
+
+fun ByteArray.toInt32(): Int? {
+    if (size != 4) return null
+    return ByteBuffer.wrap(this, 0, 4).order(ByteOrder.BIG_ENDIAN).int
+}
+
+class Tlv(val data: Map<Byte, List<ByteArray>>) {
+    fun asInt(type: Byte) = data[type]?.mapNotNull { it.toInt32() }
+    fun asHex(type: Byte) = data[type]?.map { it.toHexKey().intern() }
+    fun asString(type: Byte) = data[type]?.map { it.toString(Charsets.UTF_8) }
+
+    fun firstAsInt(type: Byte) = data[type]?.firstOrNull()?.toInt32()
+    fun firstAsHex(type: Byte) = data[type]?.firstOrNull()?.toHexKey()?.intern()
+    fun firstAsString(type: Byte) = data[type]?.firstOrNull()?.toString(Charsets.UTF_8)
+
+    companion object {
+        fun parse(data: ByteArray): Tlv {
+            val result = mutableMapOf<Byte, MutableList<ByteArray>>()
+            var rest = data
+            while (rest.isNotEmpty()) {
+                val t = rest[0]
+                val l = rest[1].toUByte().toInt()
+                val v = rest.sliceArray(IntRange(2, (2 + l) - 1))
+                rest = rest.sliceArray(IntRange(2 + l, rest.size - 1))
+                if (v.size < l) continue
+
+                if (!result.containsKey(t)) {
+                    result[t] = mutableListOf()
+                }
+                result[t]?.add(v)
+            }
+            return Tlv(result)
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/AdvertisedRelayListEvent.kt

@@ -0,0 +1,71 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class AdvertisedRelayListEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+    override fun dTag() = fixedDTag
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun relays(): List<AdvertisedRelayInfo> {
+        return tags.mapNotNull {
+            if (it.size > 1 && it[0] == "r") {
+                val type = when (it.getOrNull(2)) {
+                    "read" -> AdvertisedRelayType.READ
+                    "write" -> AdvertisedRelayType.WRITE
+                    else -> AdvertisedRelayType.BOTH
+                }
+
+                AdvertisedRelayInfo(it[1], type)
+            } else {
+                null
+            }
+        }
+    }
+
+    companion object {
+        const val kind = 10002
+        const val fixedDTag = ""
+
+        fun create(
+            list: List<AdvertisedRelayInfo>,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): AdvertisedRelayListEvent {
+            val tags = list.map {
+                if (it.type == AdvertisedRelayType.BOTH) {
+                    listOf(it.relayUrl)
+                } else {
+                    listOf(it.relayUrl, it.type.code)
+                }
+            }
+            val msg = ""
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, msg)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return AdvertisedRelayListEvent(id.toHexKey(), pubKey, createdAt, tags, msg, sig.toHexKey())
+        }
+    }
+
+    @Immutable
+    data class AdvertisedRelayInfo(val relayUrl: String, val type: AdvertisedRelayType)
+
+    @Immutable
+    enum class AdvertisedRelayType(val code: String) {
+        BOTH(""),
+        READ("read"),
+        WRITE("write")
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/AppDefinitionEvent.kt

@@ -0,0 +1,41 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+import java.io.ByteArrayInputStream
+
+@Immutable
+class AppDefinitionEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+    override fun dTag() = tags.firstOrNull { it.size > 1 && it[0] == "d" }?.get(1) ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun appMetaData() = try {
+        mapper.readValue(
+            ByteArrayInputStream(content.toByteArray(Charsets.UTF_8)),
+            UserMetadata::class.java
+        )
+    } catch (e: Exception) {
+        e.printStackTrace()
+        Log.w("MT", "Content Parse Error ${e.localizedMessage} $content")
+        null
+    }
+
+    fun supportedKinds() = tags.filter { it.size > 1 && it[0] == "k" }.mapNotNull {
+        runCatching { it[1].toInt() }.getOrNull()
+    }
+
+    fun publishedAt() = tags.firstOrNull { it.size > 1 && it[0] == "published_at" }?.get(1)
+
+    companion object {
+        const val kind = 31990
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/AppRecommendationEvent.kt

@@ -0,0 +1,28 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class AppRecommendationEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+    fun recommendations() = tags.filter { it.size > 1 && it[0] == "a" }.mapNotNull {
+        ATag.parse(it[1], it.getOrNull(2))
+    }
+
+    fun forKind() = runCatching { dTag().toInt() }.getOrNull()
+
+    override fun dTag() = tags.firstOrNull { it.size > 1 && it[0] == "d" }?.get(1) ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    companion object {
+        const val kind = 31989
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/AudioTrackEvent.kt

@@ -0,0 +1,65 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class AudioTrackEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+
+    override fun dTag() = tags.firstOrNull { it.size > 1 && it[0] == "d" }?.get(1) ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun participants() = tags.filter { it.size > 1 && it[0] == "p" }.map { Participant(it[1], it.getOrNull(2)) }
+    fun type() = tags.firstOrNull { it.size > 1 && it[0] == TYPE }?.get(1)
+    fun price() = tags.firstOrNull { it.size > 1 && it[0] == PRICE }?.get(1)
+    fun cover() = tags.firstOrNull { it.size > 1 && it[0] == COVER }?.get(1)
+
+    // fun subject() = tags.firstOrNull { it.size > 1 && it[0] == SUBJECT }?.get(1)
+    fun media() = tags.firstOrNull { it.size > 1 && it[0] == MEDIA }?.get(1)
+
+    companion object {
+        const val kind = 31337
+
+        private const val TYPE = "c"
+        private const val PRICE = "price"
+        private const val COVER = "cover"
+        private const val SUBJECT = "subject"
+        private const val MEDIA = "media"
+
+        fun create(
+            type: String,
+            media: String,
+            price: String? = null,
+            cover: String? = null,
+            subject: String? = null,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): AudioTrackEvent {
+            val tags = listOfNotNull(
+                listOf(MEDIA, media),
+                listOf(TYPE, type),
+                price?.let { listOf(PRICE, it) },
+                cover?.let { listOf(COVER, it) },
+                subject?.let { listOf(SUBJECT, it) }
+            )
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, "")
+            val sig = CryptoUtils.sign(id, privateKey)
+            return AudioTrackEvent(id.toHexKey(), pubKey, createdAt, tags, "", sig.toHexKey())
+        }
+    }
+}
+
+data class Participant(val key: String, val role: String?)

quartz/src/main/java/com/vitorpamplona/quartz/events/BadgeAwardEvent.kt

@@ -0,0 +1,22 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class BadgeAwardEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+    fun awardees() = taggedUsers()
+
+    fun awardDefinition() = taggedAddresses()
+
+    companion object {
+        const val kind = 8
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/BadgeDefinitionEvent.kt

@@ -0,0 +1,27 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class BadgeDefinitionEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+    override fun dTag() = tags.firstOrNull { it.size > 1 && it[0] == "d" }?.get(1) ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun name() = tags.firstOrNull { it.size > 1 && it[0] == "name" }?.get(1)
+    fun thumb() = tags.firstOrNull { it.size > 1 && it[0] == "thumb" }?.get(1)
+    fun image() = tags.firstOrNull { it.size > 1 && it[0] == "image" }?.get(1)
+    fun description() = tags.firstOrNull { it.size > 1 && it[0] == "description" }?.get(1)
+
+    companion object {
+        const val kind = 30009
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/BadgeProfilesEvent.kt

@@ -0,0 +1,31 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class BadgeProfilesEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+    fun badgeAwardEvents() = tags.filter { it.firstOrNull() == "e" }.mapNotNull { it.getOrNull(1) }
+    fun badgeAwardDefinitions() = tags.filter { it.firstOrNull() == "a" }.mapNotNull {
+        val aTagValue = it.getOrNull(1)
+        val relay = it.getOrNull(2)
+
+        if (aTagValue != null) ATag.parse(aTagValue, relay) else null
+    }
+
+    override fun dTag() = tags.filter { it.firstOrNull() == "d" }.mapNotNull { it.getOrNull(1) }.firstOrNull() ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    companion object {
+        const val kind = 30008
+        const val standardDTAg = "profile_badges"
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/BaseTextNoteEvent.kt

@@ -0,0 +1,148 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.encoders.HexKey
+import com.vitorpamplona.quartz.encoders.Nip19
+import com.vitorpamplona.quartz.encoders.Nip19.nip19regex
+import java.util.regex.Pattern
+
+val tagSearch = Pattern.compile("(?:\\s|\\A)\\#\\[([0-9]+)\\]")
+val hashtagSearch = Pattern.compile("(?:\\s|\\A)#([^\\s!@#\$%^&*()=+./,\\[{\\]};:'\"?><]+)")
+
+@Immutable
+open class BaseTextNoteEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    kind: Int,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+    fun mentions() = taggedUsers()
+    open fun replyTos() = taggedEvents()
+
+    @Transient
+    private var citedUsersCache: Set<HexKey>? = null
+
+    @Transient
+    private var citedNotesCache: Set<HexKey>? = null
+
+    fun citedUsers(): Set<HexKey> {
+        citedUsersCache?.let { return it }
+
+        val matcher = tagSearch.matcher(content)
+        val returningList = mutableSetOf<String>()
+        while (matcher.find()) {
+            try {
+                val tag = matcher.group(1)?.let { tags[it.toInt()] }
+                if (tag != null && tag.size > 1 && tag[0] == "p") {
+                    returningList.add(tag[1])
+                }
+            } catch (e: Exception) {
+            }
+        }
+
+        val matcher2 = nip19regex.matcher(content)
+        while (matcher2.find()) {
+            val uriScheme = matcher2.group(1) // nostr:
+            val type = matcher2.group(2) // npub1
+            val key = matcher2.group(3) // bech32
+            val additionalChars = matcher2.group(4) // additional chars
+
+            try {
+                val parsed = Nip19.parseComponents(uriScheme, type, key, additionalChars)
+
+                if (parsed != null) {
+                    val tag = tags.firstOrNull { it.size > 1 && it[1] == parsed.hex }
+
+                    if (tag != null && tag[0] == "p") {
+                        returningList.add(tag[1])
+                    }
+                }
+            } catch (e: Exception) {
+                Log.w("Unable to parse cited users that matched a NIP19 regex", e)
+            }
+        }
+
+        citedUsersCache = returningList
+        return returningList
+    }
+
+    fun findCitations(): Set<HexKey> {
+        citedNotesCache?.let { return it }
+
+        val citations = mutableSetOf<HexKey>()
+        // Removes citations from replies:
+        val matcher = tagSearch.matcher(content)
+        while (matcher.find()) {
+            try {
+                val tag = matcher.group(1)?.let { tags[it.toInt()] }
+                if (tag != null && tag.size > 1 && tag[0] == "e") {
+                    citations.add(tag[1])
+                }
+                if (tag != null && tag.size > 1 && tag[0] == "a") {
+                    citations.add(tag[1])
+                }
+            } catch (e: Exception) {
+            }
+        }
+
+        val matcher2 = nip19regex.matcher(content)
+        while (matcher2.find()) {
+            val uriScheme = matcher2.group(1) // nostr:
+            val type = matcher2.group(2) // npub1
+            val key = matcher2.group(3) // bech32
+            val additionalChars = matcher2.group(4) // additional chars
+
+            val parsed = Nip19.parseComponents(uriScheme, type, key, additionalChars)
+
+            if (parsed != null) {
+                try {
+                    val tag = tags.firstOrNull { it.size > 1 && it[1] == parsed.hex }
+
+                    if (tag != null && tag[0] == "e") {
+                        citations.add(tag[1])
+                    }
+                    if (tag != null && tag[0] == "a") {
+                        citations.add(tag[1])
+                    }
+                } catch (e: Exception) {
+                }
+            }
+        }
+
+        citedNotesCache = citations
+        return citations
+    }
+
+    fun tagsWithoutCitations(): List<String> {
+        val repliesTo = replyTos()
+        val tagAddresses = taggedAddresses().filter { it.kind != CommunityDefinitionEvent.kind }.map { it.toTag() }
+        if (repliesTo.isEmpty() && tagAddresses.isEmpty()) return emptyList()
+
+        val citations = findCitations()
+
+        return if (citations.isEmpty()) {
+            repliesTo + tagAddresses
+        } else {
+            repliesTo.filter { it !in citations }
+        }
+    }
+}
+
+fun findHashtags(content: String): List<String> {
+    val matcher = hashtagSearch.matcher(content)
+    val returningList = mutableSetOf<String>()
+    while (matcher.find()) {
+        try {
+            val tag = matcher.group(1)
+            if (tag != null && tag.isNotBlank()) {
+                returningList.add(tag)
+            }
+        } catch (e: Exception) {
+        }
+    }
+    return returningList.toList()
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/BookmarkListEvent.kt

@@ -0,0 +1,57 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class BookmarkListEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : GeneralListEvent(id, pubKey, createdAt, kind, tags, content, sig) {
+    companion object {
+        const val kind = 30001
+
+        fun create(
+            name: String = "",
+
+            events: List<String>? = null,
+            users: List<String>? = null,
+            addresses: List<ATag>? = null,
+
+            privEvents: List<String>? = null,
+            privUsers: List<String>? = null,
+            privAddresses: List<ATag>? = null,
+
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): BookmarkListEvent {
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey)
+            val content = createPrivateTags(privEvents, privUsers, privAddresses, privateKey, pubKey)
+
+            val tags = mutableListOf<List<String>>()
+            tags.add(listOf("d", name))
+
+            events?.forEach {
+                tags.add(listOf("e", it))
+            }
+            users?.forEach {
+                tags.add(listOf("p", it))
+            }
+            addresses?.forEach {
+                tags.add(listOf("a", it.toTag()))
+            }
+
+            val id = generateId(pubKey.toHexKey(), createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return BookmarkListEvent(id.toHexKey(), pubKey.toHexKey(), createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/ChannelCreateEvent.kt

@@ -0,0 +1,52 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.fasterxml.jackson.module.kotlin.readValue
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class ChannelCreateEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+    fun channelInfo(): ChannelData = try {
+        mapper.readValue(content)
+    } catch (e: Exception) {
+        Log.e("ChannelMetadataEvent", "Can't parse channel info $content", e)
+        ChannelData(null, null, null)
+    }
+
+    companion object {
+        const val kind = 40
+
+        fun create(channelInfo: ChannelData?, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ChannelCreateEvent {
+            val content = try {
+                if (channelInfo != null) {
+                    mapper.writeValueAsString(channelInfo)
+                } else {
+                    ""
+                }
+            } catch (t: Throwable) {
+                Log.e("ChannelCreateEvent", "Couldn't parse channel information", t)
+                ""
+            }
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags = emptyList<List<String>>()
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return ChannelCreateEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+
+    @Immutable
+    data class ChannelData(val name: String?, val about: String?, val picture: String?)
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/ChannelHideMessageEvent.kt

@@ -0,0 +1,41 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class ChannelHideMessageEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), IsInPublicChatChannel {
+    override fun channel() = tags.firstOrNull {
+        it.size > 3 && it[0] == "e" && it[3] == "root"
+    }?.get(1) ?: tags.firstOrNull {
+        it.size > 1 && it[0] == "e"
+    }?.get(1)
+
+    fun eventsToHide() = tags.filter { it.firstOrNull() == "e" }.mapNotNull { it.getOrNull(1) }
+
+    companion object {
+        const val kind = 43
+
+        fun create(reason: String, messagesToHide: List<String>?, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ChannelHideMessageEvent {
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags =
+                messagesToHide?.map {
+                    listOf("e", it)
+                } ?: emptyList()
+
+            val id = generateId(pubKey, createdAt, kind, tags, reason)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return ChannelHideMessageEvent(id.toHexKey(), pubKey, createdAt, tags, reason, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/ChannelMessageEvent.kt

@@ -0,0 +1,75 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class ChannelMessageEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : BaseTextNoteEvent(id, pubKey, createdAt, kind, tags, content, sig), IsInPublicChatChannel {
+
+    override fun channel() = tags.firstOrNull {
+        it.size > 3 && it[0] == "e" && it[3] == "root"
+    }?.get(1) ?: tags.firstOrNull {
+        it.size > 1 && it[0] == "e"
+    }?.get(1)
+
+    override fun replyTos() = tags.filter { it.firstOrNull() == "e" && it.getOrNull(1) != channel() }.mapNotNull { it.getOrNull(1) }
+
+    companion object {
+        const val kind = 42
+
+        fun create(
+            message: String,
+            channel: String,
+            replyTos: List<String>? = null,
+            mentions: List<String>? = null,
+            zapReceiver: String?,
+            pubKey: HexKey,
+            privateKey: ByteArray?,
+            createdAt: Long = TimeUtils.now(),
+            markAsSensitive: Boolean,
+            zapRaiserAmount: Long?,
+            geohash: String? = null
+        ): ChannelMessageEvent {
+            val content = message
+            val tags = mutableListOf(
+                listOf("e", channel, "", "root")
+            )
+            replyTos?.forEach {
+                tags.add(listOf("e", it))
+            }
+            mentions?.forEach {
+                tags.add(listOf("p", it))
+            }
+            zapReceiver?.let {
+                tags.add(listOf("zap", it))
+            }
+            if (markAsSensitive) {
+                tags.add(listOf("content-warning", ""))
+            }
+            zapRaiserAmount?.let {
+                tags.add(listOf("zapraiser", "$it"))
+            }
+            geohash?.let {
+                tags.add(listOf("g", it))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = if (privateKey == null) null else CryptoUtils.sign(id, privateKey)
+            return ChannelMessageEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig?.toHexKey() ?: "")
+        }
+    }
+}
+
+interface IsInPublicChatChannel {
+    open fun channel(): String?
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/ChannelMetadataEvent.kt

@@ -0,0 +1,47 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class ChannelMetadataEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), IsInPublicChatChannel {
+
+    override fun channel() = tags.firstOrNull { it.size > 1 && it[0] == "e" }?.get(1)
+    fun channelInfo() =
+        try {
+            mapper.readValue(content, ChannelCreateEvent.ChannelData::class.java)
+        } catch (e: Exception) {
+            Log.e("ChannelMetadataEvent", "Can't parse channel info $content", e)
+            ChannelCreateEvent.ChannelData(null, null, null)
+        }
+
+    companion object {
+        const val kind = 41
+
+        fun create(newChannelInfo: ChannelCreateEvent.ChannelData?, originalChannelIdHex: String, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ChannelMetadataEvent {
+            val content =
+                if (newChannelInfo != null) {
+                    mapper.writeValueAsString(newChannelInfo)
+                } else {
+                    ""
+                }
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags = listOf(listOf("e", originalChannelIdHex, "", "root"))
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return ChannelMetadataEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/ChannelMuteUserEvent.kt

@@ -0,0 +1,42 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class ChannelMuteUserEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), IsInPublicChatChannel {
+    override fun channel() = tags.firstOrNull {
+        it.size > 3 && it[0] == "e" && it[3] == "root"
+    }?.get(1) ?: tags.firstOrNull {
+        it.size > 1 && it[0] == "e"
+    }?.get(1)
+
+    fun usersToMute() = tags.filter { it.firstOrNull() == "p" }.mapNotNull { it.getOrNull(1) }
+
+    companion object {
+        const val kind = 44
+
+        fun create(reason: String, usersToMute: List<String>?, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ChannelMuteUserEvent {
+            val content = reason
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags =
+                usersToMute?.map {
+                    listOf("p", it)
+                } ?: emptyList()
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return ChannelMuteUserEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/ChatMessageEvent.kt

@@ -0,0 +1,109 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.Stable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+import kotlinx.collections.immutable.ImmutableSet
+import kotlinx.collections.immutable.toImmutableSet
+
+@Immutable
+class ChatMessageEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), ChatroomKeyable {
+    /**
+     * Recepients intended to receive this conversation
+     */
+    fun recipientsPubKey() = tags.mapNotNull {
+        if (it.size > 1 && it[0] == "p") it[1] else null
+    }
+
+    fun replyTo() = tags.firstOrNull { it.size > 1 && it[0] == "e" }?.get(1)
+
+    fun talkingWith(oneSideHex: String): Set<HexKey> {
+        val listedPubKeys = recipientsPubKey()
+
+        val result = if (pubKey == oneSideHex) {
+            listedPubKeys.toSet().minus(oneSideHex)
+        } else {
+            listedPubKeys.plus(pubKey).toSet().minus(oneSideHex)
+        }
+
+        if (result.isEmpty()) {
+            // talking to myself
+            return setOf(pubKey)
+        }
+
+        return result
+    }
+
+    override fun chatroomKey(toRemove: String): ChatroomKey {
+        return ChatroomKey(talkingWith(toRemove).toImmutableSet())
+    }
+
+    companion object {
+        const val kind = 14
+
+        fun create(
+            msg: String,
+            to: List<String>? = null,
+            subject: String? = null,
+            replyTos: List<String>? = null,
+            mentions: List<String>? = null,
+            zapReceiver: String? = null,
+            markAsSensitive: Boolean = false,
+            zapRaiserAmount: Long? = null,
+            geohash: String? = null,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): ChatMessageEvent {
+            val content = msg
+            val tags = mutableListOf<List<String>>()
+            to?.forEach {
+                tags.add(listOf("p", it))
+            }
+            replyTos?.forEach {
+                tags.add(listOf("e", it))
+            }
+            mentions?.forEach {
+                tags.add(listOf("p", it, "", "mention"))
+            }
+            zapReceiver?.let {
+                tags.add(listOf("zap", it))
+            }
+            if (markAsSensitive) {
+                tags.add(listOf("content-warning", ""))
+            }
+            zapRaiserAmount?.let {
+                tags.add(listOf("zapraiser", "$it"))
+            }
+            geohash?.let {
+                tags.add(listOf("g", it))
+            }
+            subject?.let {
+                tags.add(listOf("subject", it))
+            }
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, ClassifiedsEvent.kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return ChatMessageEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}
+
+interface ChatroomKeyable {
+    fun chatroomKey(toRemove: HexKey): ChatroomKey
+}
+
+@Stable
+data class ChatroomKey(
+    val users: ImmutableSet<HexKey>
+)

quartz/src/main/java/com/vitorpamplona/quartz/events/ClassifiedsEvent.kt

@@ -0,0 +1,78 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class ClassifiedsEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+
+    override fun dTag() = tags.firstOrNull { it.size > 1 && it[0] == "d" }?.get(1) ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun title() = tags.firstOrNull { it.size > 1 && it[0] == "title" }?.get(1)
+    fun image() = tags.firstOrNull { it.size > 1 && it[0] == "image" }?.get(1)
+    fun summary() = tags.firstOrNull { it.size > 1 && it[0] == "summary" }?.get(1)
+    fun price() = tags.firstOrNull { it.size > 1 && it[0] == "price" }?.let {
+        Price(it[1], it.getOrNull(2), it.getOrNull(3))
+    }
+    fun location() = tags.firstOrNull { it.size > 1 && it[0] == "location" }?.get(1)
+
+    fun publishedAt() = try {
+        tags.firstOrNull { it.size > 1 && it[0] == "published_at" }?.get(1)?.toLongOrNull()
+    } catch (_: Exception) {
+        null
+    }
+
+    companion object {
+        const val kind = 30402
+
+        fun create(
+            dTag: String,
+            title: String?,
+            image: String?,
+            summary: String?,
+            price: Price?,
+            location: String?,
+            publishedAt: Long?,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): ClassifiedsEvent {
+            val tags = mutableListOf<List<String>>()
+
+            tags.add(listOf("d", dTag))
+            title?.let { tags.add(listOf("title", it)) }
+            image?.let { tags.add(listOf("image", it)) }
+            summary?.let { tags.add(listOf("summary", it)) }
+            price?.let {
+                if (it.frequency != null && it.currency != null) {
+                    tags.add(listOf("price", it.amount, it.currency, it.frequency))
+                } else if (it.currency != null) {
+                    tags.add(listOf("price", it.amount, it.currency))
+                } else {
+                    tags.add(listOf("price", it.amount))
+                }
+            }
+            location?.let { tags.add(listOf("location", it)) }
+            publishedAt?.let { tags.add(listOf("publishedAt", it.toString())) }
+            title?.let { tags.add(listOf("title", it)) }
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, "")
+            val sig = CryptoUtils.sign(id, privateKey)
+            return ClassifiedsEvent(id.toHexKey(), pubKey, createdAt, tags, "", sig.toHexKey())
+        }
+    }
+}
+
+data class Price(val amount: String, val currency: String?, val frequency: String?)

quartz/src/main/java/com/vitorpamplona/quartz/events/CommunityDefinitionEvent.kt

@@ -0,0 +1,43 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class CommunityDefinitionEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+
+    override fun dTag() = tags.firstOrNull { it.size > 1 && it[0] == "d" }?.get(1) ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun description() = tags.firstOrNull { it.size > 1 && it[0] == "description" }?.get(1)
+    fun image() = tags.firstOrNull { it.size > 1 && it[0] == "image" }?.get(1)
+    fun rules() = tags.firstOrNull { it.size > 1 && it[0] == "rules" }?.get(1)
+
+    fun moderators() = tags.filter { it.size > 1 && it[0] == "p" }.map { Participant(it[1], it.getOrNull(3)) }
+
+    companion object {
+        const val kind = 34550
+
+        fun create(
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): CommunityDefinitionEvent {
+            val tags = mutableListOf<List<String>>()
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, "")
+            val sig = CryptoUtils.sign(id, privateKey)
+            return CommunityDefinitionEvent(id.toHexKey(), pubKey, createdAt, tags, "", sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/CommunityPostApprovalEvent.kt

@@ -0,0 +1,63 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class CommunityPostApprovalEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+    fun containedPost(): Event? = try {
+        content.ifBlank { null }?.let {
+            fromJson(it)
+        }
+    } catch (e: Exception) {
+        Log.w("CommunityPostEvent", "Failed to Parse Community Approval Contained Post of $id with $content")
+        null
+    }
+
+    fun communities() = tags.filter { it.size > 1 && it[0] == "a" }.mapNotNull {
+        val aTag = ATag.parse(it[1], it.getOrNull(2))
+
+        if (aTag?.kind == CommunityDefinitionEvent.kind) {
+            aTag
+        } else {
+            null
+        }
+    }
+
+    fun approvedEvents() = tags.filter {
+        it.size > 1 && (it[0] == "e" || (it[0] == "a" && ATag.parse(it[1], null)?.kind != CommunityDefinitionEvent.kind))
+    }.map {
+        it[1]
+    }
+
+    companion object {
+        const val kind = 4550
+
+        fun create(approvedPost: Event, community: CommunityDefinitionEvent, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): GenericRepostEvent {
+            val content = approvedPost.toJson()
+
+            val communities = listOf("a", community.address().toTag())
+            val replyToPost = listOf("e", approvedPost.id())
+            val replyToAuthor = listOf("p", approvedPost.pubKey())
+            val kind = listOf("k", "${approvedPost.kind()}")
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags: List<List<String>> = listOf(communities, replyToPost, replyToAuthor, kind)
+            val id = generateId(pubKey, createdAt, GenericRepostEvent.kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return GenericRepostEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/ContactListEvent.kt

@@ -0,0 +1,460 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.Stable
+import com.fasterxml.jackson.module.kotlin.readValue
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+import com.vitorpamplona.quartz.encoders.decodePublicKey
+
+@Immutable
+data class Contact(val pubKeyHex: String, val relayUri: String?)
+
+@Stable
+class ContactListEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+    // This function is only used by the user logged in
+    // But it is used all the time.
+
+    @delegate:Transient
+    val verifiedFollowKeySet: Set<HexKey> by lazy {
+        tags.filter { it.size > 1 && it[0] == "p" }.mapNotNull {
+            try {
+                decodePublicKey(it[1]).toHexKey()
+            } catch (e: Exception) {
+                Log.w("ContactListEvent", "Can't parse tags as a follows: ${it[1]}", e)
+                null
+            }
+        }.toSet()
+    }
+
+    @delegate:Transient
+    val verifiedFollowTagSet: Set<String> by lazy {
+        unverifiedFollowTagSet().map { it.lowercase() }.toSet()
+    }
+
+    @delegate:Transient
+    val verifiedFollowGeohashSet: Set<String> by lazy {
+        unverifiedFollowGeohashSet().map { it.lowercase() }.toSet()
+    }
+
+    @delegate:Transient
+    val verifiedFollowCommunitySet: Set<String> by lazy {
+        unverifiedFollowAddressSet().toSet()
+    }
+
+    @delegate:Transient
+    val verifiedFollowKeySetAndMe: Set<HexKey> by lazy {
+        verifiedFollowKeySet + pubKey
+    }
+
+    fun unverifiedFollowKeySet() = tags.filter { it[0] == "p" }.mapNotNull { it.getOrNull(1) }
+    fun unverifiedFollowTagSet() = tags.filter { it[0] == "t" }.mapNotNull { it.getOrNull(1) }
+    fun unverifiedFollowGeohashSet() = tags.filter { it[0] == "g" }.mapNotNull { it.getOrNull(1) }
+
+    fun unverifiedFollowAddressSet() = tags.filter { it[0] == "a" }.mapNotNull { it.getOrNull(1) }
+
+    fun follows() = tags.filter { it[0] == "p" }.mapNotNull {
+        try {
+            Contact(decodePublicKey(it[1]).toHexKey(), it.getOrNull(2))
+        } catch (e: Exception) {
+            Log.w("ContactListEvent", "Can't parse tags as a follows: ${it[1]}", e)
+            null
+        }
+    }
+
+    fun followsTags() = tags.filter { it[0] == "t" }.mapNotNull {
+        it.getOrNull(2)
+    }
+
+    fun relays(): Map<String, ReadWrite>? = try {
+        if (content.isNotEmpty()) {
+            mapper.readValue<Map<String, ReadWrite>>(content)
+        } else {
+            null
+        }
+    } catch (e: Exception) {
+        Log.w("ContactListEvent", "Can't parse content as relay lists: $content", e)
+        null
+    }
+
+    companion object {
+        const val kind = 3
+
+        fun createFromScratch(
+            followUsers: List<Contact>,
+            followTags: List<String>,
+            followGeohashes: List<String>,
+            followCommunities: List<ATag>,
+            followEvents: List<String>,
+            relayUse: Map<String, ReadWrite>?,
+            privateKey: ByteArray?,
+            createdAt: Long = TimeUtils.now(),
+            publicKey: ByteArray? = null
+        ): ContactListEvent {
+            val content = if (relayUse != null) {
+                mapper.writeValueAsString(relayUse)
+            } else {
+                ""
+            }
+
+            val tags = followUsers.map {
+                if (it.relayUri != null) {
+                    listOf("p", it.pubKeyHex, it.relayUri)
+                } else {
+                    listOf("p", it.pubKeyHex)
+                }
+            } + followTags.map {
+                listOf("t", it)
+            } + followEvents.map {
+                listOf("e", it)
+            } + followCommunities.map {
+                if (it.relay != null) {
+                    listOf("a", it.toTag(), it.relay)
+                } else {
+                    listOf("a", it.toTag())
+                }
+            } + followGeohashes.map {
+                listOf("g", it)
+            }
+
+            if (publicKey == null) {
+                return create(
+                    content = content,
+                    tags = tags,
+                    privateKey = privateKey!!,
+                    createdAt = createdAt
+                )
+            }
+            return create(
+                content = content,
+                tags = tags,
+                pubKey = publicKey.toHexKey(),
+                createdAt = createdAt
+            )
+        }
+
+        fun followUser(earlierVersion: ContactListEvent, pubKeyHex: String, pubKey: HexKey, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (earlierVersion.isTaggedUser(pubKeyHex)) return earlierVersion
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.plus(element = listOf("p", pubKeyHex)),
+                pubKey = pubKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun followUser(earlierVersion: ContactListEvent, pubKeyHex: String, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (earlierVersion.isTaggedUser(pubKeyHex)) return earlierVersion
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.plus(element = listOf("p", pubKeyHex)),
+                privateKey = privateKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun unfollowUser(earlierVersion: ContactListEvent, pubKeyHex: String, pubKey: HexKey, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (!earlierVersion.isTaggedUser(pubKeyHex)) return earlierVersion
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.filter { it.size > 1 && it[1] != pubKeyHex },
+                pubKey = pubKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun unfollowUser(earlierVersion: ContactListEvent, pubKeyHex: String, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (!earlierVersion.isTaggedUser(pubKeyHex)) return earlierVersion
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.filter { it.size > 1 && it[1] != pubKeyHex },
+                privateKey = privateKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun followHashtag(earlierVersion: ContactListEvent, hashtag: String, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (earlierVersion.isTaggedHash(hashtag)) return earlierVersion
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.plus(element = listOf("t", hashtag)),
+                privateKey = privateKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun followHashtag(earlierVersion: ContactListEvent, hashtag: String, pubKey: HexKey, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (earlierVersion.isTaggedHash(hashtag)) return earlierVersion
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.plus(element = listOf("t", hashtag)),
+                pubKey = pubKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun unfollowHashtag(earlierVersion: ContactListEvent, hashtag: String, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (!earlierVersion.isTaggedHash(hashtag)) return earlierVersion
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.filter { it.size > 1 && it[1] != hashtag },
+                privateKey = privateKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun unfollowHashtag(earlierVersion: ContactListEvent, hashtag: String, pubKey: HexKey, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (!earlierVersion.isTaggedHash(hashtag)) return earlierVersion
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.filter { it.size > 1 && it[1] != hashtag },
+                pubKey = pubKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun followGeohash(earlierVersion: ContactListEvent, hashtag: String, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (earlierVersion.isTaggedGeoHash(hashtag)) return earlierVersion
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.plus(element = listOf("g", hashtag)),
+                privateKey = privateKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun unfollowGeohash(earlierVersion: ContactListEvent, hashtag: String, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (!earlierVersion.isTaggedGeoHash(hashtag)) return earlierVersion
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.filter { it.size > 1 && it[1] != hashtag },
+                privateKey = privateKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun followEvent(earlierVersion: ContactListEvent, idHex: String, pubKey: HexKey, privateKey: ByteArray?, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (earlierVersion.isTaggedEvent(idHex)) return earlierVersion
+
+            if (privateKey == null) {
+                return create(
+                    content = earlierVersion.content,
+                    tags = earlierVersion.tags.plus(element = listOf("e", idHex)),
+                    pubKey = pubKey,
+                    createdAt = createdAt
+                )
+            }
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.plus(element = listOf("e", idHex)),
+                privateKey = privateKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun followEvent(earlierVersion: ContactListEvent, idHex: String, pubKey: HexKey, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (earlierVersion.isTaggedEvent(idHex)) return earlierVersion
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.plus(element = listOf("e", idHex)),
+                pubKey = pubKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun unfollowEvent(earlierVersion: ContactListEvent, idHex: String, publicKey: HexKey, privateKey: ByteArray?, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (!earlierVersion.isTaggedEvent(idHex)) return earlierVersion
+
+            if (privateKey == null) {
+                return create(
+                    content = earlierVersion.content,
+                    tags = earlierVersion.tags.filter { it.size > 1 && it[1] != idHex },
+                    pubKey = publicKey,
+                    createdAt = createdAt
+                )
+            }
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.filter { it.size > 1 && it[1] != idHex },
+                privateKey = privateKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun followAddressableEvent(earlierVersion: ContactListEvent, aTag: ATag, pubKey: HexKey, privateKey: ByteArray?, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (earlierVersion.isTaggedAddressableNote(aTag.toTag())) return earlierVersion
+
+            if (privateKey == null) {
+                return create(
+                    content = earlierVersion.content,
+                    tags = earlierVersion.tags.plus(element = listOfNotNull("a", aTag.toTag(), aTag.relay)),
+                    pubKey = pubKey,
+                    createdAt = createdAt
+                )
+            }
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.plus(element = listOfNotNull("a", aTag.toTag(), aTag.relay)),
+                privateKey = privateKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun followAddressableEvent(earlierVersion: ContactListEvent, aTag: ATag, pubKey: HexKey, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (earlierVersion.isTaggedAddressableNote(aTag.toTag())) return earlierVersion
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.plus(element = listOfNotNull("a", aTag.toTag(), aTag.relay)),
+                pubKey = pubKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun unfollowAddressableEvent(earlierVersion: ContactListEvent, aTag: ATag, pubKey: HexKey, privateKey: ByteArray?, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            if (!earlierVersion.isTaggedAddressableNote(aTag.toTag())) return earlierVersion
+
+            if (privateKey == null) {
+                return create(
+                    content = earlierVersion.content,
+                    tags = earlierVersion.tags.filter { it.size > 1 && it[1] != aTag.toTag() },
+                    pubKey = pubKey,
+                    createdAt = createdAt
+                )
+            }
+
+            return create(
+                content = earlierVersion.content,
+                tags = earlierVersion.tags.filter { it.size > 1 && it[1] != aTag.toTag() },
+                privateKey = privateKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun updateRelayList(earlierVersion: ContactListEvent, relayUse: Map<String, ReadWrite>?, pubKey: HexKey, privateKey: ByteArray?, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            val content = if (relayUse != null) {
+                mapper.writeValueAsString(relayUse)
+            } else {
+                ""
+            }
+
+            if (privateKey == null) {
+                return create(
+                    content = content,
+                    tags = earlierVersion.tags,
+                    pubKey = pubKey,
+                    createdAt = createdAt
+                )
+            }
+
+            return create(
+                content = content,
+                tags = earlierVersion.tags,
+                privateKey = privateKey,
+                createdAt = createdAt
+            )
+        }
+
+        fun create(content: String, tags: List<List<String>>, pubKey: HexKey, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            return ContactListEvent(id.toHexKey(), pubKey, createdAt, tags, content, "")
+        }
+
+        fun create(content: String, tags: List<List<String>>, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ContactListEvent {
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return ContactListEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+
+    data class ReadWrite(val read: Boolean, val write: Boolean)
+}
+
+@Stable
+class UserMetadata {
+    var name: String? = null
+    var username: String? = null
+    var display_name: String? = null
+    var displayName: String? = null
+    var picture: String? = null
+    var banner: String? = null
+    var website: String? = null
+    var about: String? = null
+
+    var nip05: String? = null
+    var nip05Verified: Boolean = false
+    var nip05LastVerificationTime: Long? = 0
+
+    var domain: String? = null
+    var lud06: String? = null
+    var lud16: String? = null
+
+    var twitter: String? = null
+
+    var updatedMetadataAt: Long = 0
+    var latestMetadata: MetadataEvent? = null
+    var tags: ImmutableListOfLists<String>? = null
+
+    fun anyName(): String? {
+        return display_name ?: displayName ?: name ?: username
+    }
+
+    fun anyNameStartsWith(prefix: String): Boolean {
+        return listOfNotNull(name, username, display_name, displayName, nip05, lud06, lud16)
+            .any { it.contains(prefix, true) }
+    }
+
+    fun lnAddress(): String? {
+        return (lud16?.trim() ?: lud06?.trim())?.ifBlank { null }
+    }
+
+    fun bestUsername(): String? {
+        return name?.ifBlank { null } ?: username?.ifBlank { null }
+    }
+
+    fun bestDisplayName(): String? {
+        return displayName?.ifBlank { null } ?: display_name?.ifBlank { null }
+    }
+
+    fun nip05(): String? {
+        return nip05?.ifBlank { null }
+    }
+
+    fun profilePicture(): String? {
+        if (picture.isNullOrBlank()) picture = null
+        return picture
+    }
+}
+
+@Stable
+data class ImmutableListOfLists<T>(val lists: List<List<T>> = emptyList())
+
+fun List<List<String>>.toImmutableListOfLists(): ImmutableListOfLists<String> {
+    return ImmutableListOfLists(this)
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/DeletionEvent.kt

@@ -0,0 +1,39 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class DeletionEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+    fun deleteEvents() = tags.map { it[1] }
+
+    companion object {
+        const val kind = 5
+
+        fun create(deleteEvents: List<String>, pubKey: HexKey, createdAt: Long = TimeUtils.now()): DeletionEvent {
+            val content = ""
+            val tags = deleteEvents.map { listOf("e", it) }
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            return DeletionEvent(id.toHexKey(), pubKey, createdAt, tags, content, "")
+        }
+
+        fun create(deleteEvents: List<String>, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): DeletionEvent {
+            val content = ""
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags = deleteEvents.map { listOf("e", it) }
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return DeletionEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/EmojiPackEvent.kt

@@ -0,0 +1,56 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class EmojiPackEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : GeneralListEvent(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    companion object {
+        const val kind = 30030
+
+        fun create(
+            name: String = "",
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): EmojiPackEvent {
+            val content = ""
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey)
+
+            val tags = mutableListOf<List<String>>()
+            tags.add(listOf("d", name))
+
+            val id = generateId(pubKey.toHexKey(), createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return EmojiPackEvent(id.toHexKey(), pubKey.toHexKey(), createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}
+
+@Immutable
+data class EmojiUrl(val code: String, val url: String) {
+    fun encode(): String {
+        return ":$code:$url"
+    }
+
+    companion object {
+        fun decode(encodedEmojiSetup: String): EmojiUrl? {
+            val emojiParts = encodedEmojiSetup.split(":", limit = 3)
+            return if (emojiParts.size > 2) {
+                EmojiUrl(emojiParts[1], emojiParts[2])
+            } else {
+                null
+            }
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/EmojiPackSelectionEvent.kt

@@ -0,0 +1,44 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class EmojiPackSelectionEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+
+    override fun dTag() = ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    companion object {
+        const val kind = 10030
+
+        fun create(
+            listOfEmojiPacks: List<ATag>?,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): EmojiPackSelectionEvent {
+            val msg = ""
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags = mutableListOf<List<String>>()
+
+            listOfEmojiPacks?.forEach {
+                tags.add(listOf("a", it.toTag()))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, msg)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return EmojiPackSelectionEvent(id.toHexKey(), pubKey, createdAt, tags, msg, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/Event.kt

@@ -0,0 +1,374 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.fasterxml.jackson.annotation.JsonProperty
+import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.core.JsonParser
+import com.fasterxml.jackson.databind.DeserializationContext
+import com.fasterxml.jackson.databind.DeserializationFeature
+import com.fasterxml.jackson.databind.JsonNode
+import com.fasterxml.jackson.databind.SerializerProvider
+import com.fasterxml.jackson.databind.deser.std.StdDeserializer
+import com.fasterxml.jackson.databind.module.SimpleModule
+import com.fasterxml.jackson.databind.ser.std.StdSerializer
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.Hex
+import com.vitorpamplona.quartz.encoders.HexKey
+import com.vitorpamplona.quartz.encoders.Nip19
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.utils.TimeUtils
+import java.math.BigDecimal
+import java.util.*
+
+
+@Immutable
+open class Event(
+    val id: HexKey,
+    @JsonProperty("pubkey")
+    val pubKey: HexKey,
+    @JsonProperty("created_at")
+    val createdAt: Long,
+    val kind: Int,
+    val tags: List<List<String>>,
+    val content: String,
+    val sig: HexKey
+) : EventInterface {
+
+    override fun countMemory(): Long {
+        return 12L +
+            id.bytesUsedInMemory() +
+            pubKey.bytesUsedInMemory() +
+            tags.sumOf { it.sumOf { it.bytesUsedInMemory() } } +
+            content.bytesUsedInMemory() +
+            sig.bytesUsedInMemory()
+    }
+
+    override fun id(): HexKey = id
+
+    override fun pubKey(): HexKey = pubKey
+
+    override fun createdAt(): Long = createdAt
+
+    override fun kind(): Int = kind
+
+    override fun tags(): List<List<String>> = tags
+
+    override fun content(): String = content
+
+    override fun sig(): HexKey = sig
+
+    override fun toJson(): String = mapper.writeValueAsString(toJsonObject())
+
+    fun hasAnyTaggedUser() = tags.any { it.size > 1 && it[0] == "p" }
+
+    override fun taggedUsers() = tags.filter { it.size > 1 && it[0] == "p" }.map { it[1] }
+    override fun taggedEvents() = tags.filter { it.size > 1 && it[0] == "e" }.map { it[1] }
+
+    override fun taggedUrls() = tags.filter { it.size > 1 && it[0] == "r" }.map { it[1] }
+
+    override fun taggedEmojis() = tags.filter { it.size > 2 && it[0] == "emoji" }.map { EmojiUrl(it[1], it[2]) }
+
+    override fun isSensitive() = tags.any {
+        (it.size > 0 && it[0].equals("content-warning", true)) ||
+            (it.size > 1 && it[0] == "t" && it[1].equals("nsfw", true)) ||
+            (it.size > 1 && it[0] == "t" && it[1].equals("nude", true))
+    }
+
+    override fun subject() = tags.firstOrNull() { it.size > 1 && it[0] == "subject" }?.get(1)
+
+    override fun zapraiserAmount() = tags.firstOrNull() {
+        (it.size > 1 && it[0] == "zapraiser")
+    }?.get(1)?.toLongOrNull()
+
+    override fun zapAddress() = tags.firstOrNull { it.size > 1 && it[0] == "zap" }?.get(1)
+
+    override fun taggedAddresses() = tags.filter { it.size > 1 && it[0] == "a" }.mapNotNull {
+        val aTagValue = it[1]
+        val relay = it.getOrNull(2)
+
+        ATag.parse(aTagValue, relay)
+    }
+
+    override fun hashtags() = tags.filter { it.size > 1 && it[0] == "t" }.map { it[1] }
+    override fun geohashes() = tags.filter { it.size > 1 && it[0] == "g" }.map { it[1] }
+
+    override fun matchTag1With(text: String) = tags.any { it.size > 1 && it[1].contains(text, true) }
+
+    override fun isTaggedUser(idHex: String) = tags.any { it.size > 1 && it[0] == "p" && it[1] == idHex }
+
+    override fun isTaggedEvent(idHex: String) = tags.any { it.size > 1 && it[0] == "e" && it[1] == idHex }
+
+    override fun isTaggedAddressableNote(idHex: String) = tags.any { it.size > 1 && it[0] == "a" && it[1] == idHex }
+
+    override fun isTaggedAddressableNotes(idHexes: Set<String>) = tags.any { it.size > 1 && it[0] == "a" && it[1] in idHexes }
+
+    override fun isTaggedHash(hashtag: String) = tags.any { it.size > 1 && it[0] == "t" && it[1].equals(hashtag, true) }
+
+    override fun isTaggedGeoHash(hashtag: String) = tags.any { it.size > 1 && it[0] == "g" && it[1].startsWith(hashtag, true) }
+    override fun isTaggedHashes(hashtags: Set<String>) = tags.any { it.size > 1 && it[0] == "t" && it[1].lowercase() in hashtags }
+    override fun isTaggedGeoHashes(hashtags: Set<String>) = tags.any { it.size > 1 && it[0] == "g" && it[1].lowercase() in hashtags }
+    override fun firstIsTaggedHashes(hashtags: Set<String>) = tags.firstOrNull { it.size > 1 && it[0] == "t" && it[1].lowercase() in hashtags }?.getOrNull(1)
+
+    override fun firstIsTaggedAddressableNote(addressableNotes: Set<String>) = tags.firstOrNull { it.size > 1 && it[0] == "a" && it[1] in addressableNotes }?.getOrNull(1)
+
+    override fun isTaggedAddressableKind(kind: Int): Boolean {
+        val kindStr = kind.toString()
+        return tags.any { it.size > 1 && it[0] == "a" && it[1].startsWith(kindStr) }
+    }
+
+    override fun getTagOfAddressableKind(kind: Int): ATag? {
+        val kindStr = kind.toString()
+        val aTag = tags
+            .firstOrNull { it.size > 1 && it[0] == "a" && it[1].startsWith(kindStr) }
+            ?.getOrNull(1)
+            ?: return null
+
+        return ATag.parse(aTag, null)
+    }
+
+    override fun getPoWRank(): Int {
+        var rank = 0
+        for (i in 0..id.length) {
+            if (id[i] == '0') {
+                rank += 4
+            } else if (id[i] in '4'..'7') {
+                rank += 1
+                break
+            } else if (id[i] in '2'..'3') {
+                rank += 2
+                break
+            } else if (id[i] == '1') {
+                rank += 3
+                break
+            } else {
+                break
+            }
+        }
+        return rank
+    }
+
+    override fun getGeoHash(): String? {
+        return tags.firstOrNull { it.size > 1 && it[0] == "g" }?.get(1)?.ifBlank { null }
+    }
+
+    override fun getReward(): BigDecimal? {
+        return try {
+            tags.firstOrNull { it.size > 1 && it[0] == "reward" }?.get(1)?.let { BigDecimal(it) }
+        } catch (e: Exception) {
+            null
+        }
+    }
+
+    open fun toNIP19(): String {
+        return if (this is AddressableEvent) {
+            ATag(kind, pubKey, dTag(), null).toNAddr()
+        } else {
+            Nip19.createNEvent(id, pubKey, kind, null)
+        }
+    }
+
+    fun toNostrUri(): String {
+        return "nostr:${toNIP19()}"
+    }
+
+    fun hasCorrectIDHash() = id.equals(generateId())
+    fun hasVerifedSignature() = CryptoUtils.verifySignature(Hex.decode(sig), Hex.decode(id), Hex.decode(pubKey))
+
+    /**
+     * Checks if the ID is correct and then if the pubKey's secret key signed the event.
+     */
+    override fun checkSignature() {
+        if (!hasCorrectIDHash()) {
+            throw Exception(
+                """|Unexpected ID.
+                   |  Event: ${toJson()}
+                   |  Actual ID: $id
+                   |  Generated: ${generateId()}
+                """.trimIndent()
+            )
+        }
+        if (!hasVerifedSignature()) {
+            throw Exception("""Bad signature!""")
+        }
+    }
+
+    override fun hasValidSignature(): Boolean {
+        return try {
+            hasCorrectIDHash() && hasVerifedSignature()
+        } catch (e: Exception) {
+            Log.e("Event", "Fail checking if event $id has a valid signature", e)
+            false
+        }
+    }
+
+    fun makeJsonForId(): String {
+        return makeJsonForId(pubKey, createdAt, kind, tags, content)
+    }
+
+    private fun generateId(): String {
+        return CryptoUtils.sha256(makeJsonForId().toByteArray()).toHexKey()
+    }
+
+    private class EventDeserializer : StdDeserializer<Event>(Event::class.java) {
+        override fun deserialize(jp: JsonParser, ctxt: DeserializationContext): Event {
+            return fromJson(jp.codec.readTree(jp))
+        }
+    }
+
+    private class GossipDeserializer : StdDeserializer<Gossip>(Gossip::class.java) {
+        override fun deserialize(jp: JsonParser, ctxt: DeserializationContext): Gossip {
+            val jsonObject: JsonNode = jp.codec.readTree(jp)
+            return Gossip(
+                id = jsonObject.get("id")?.asText()?.intern(),
+                pubKey = jsonObject.get("pubkey")?.asText()?.intern(),
+                createdAt = jsonObject.get("created_at")?.asLong(),
+                kind = jsonObject.get("kind")?.asInt(),
+                tags = jsonObject.get("tags")?.map {
+                    it.mapNotNull { s -> if (s?.isNull ?: true) null else s.asText().intern() }
+                },
+                content = jsonObject.get("content")?.asText()
+            )
+        }
+    }
+
+    private class EventSerializer: StdSerializer<Event>(Event::class.java) {
+        override fun serialize(event: Event, gen: JsonGenerator, provider: SerializerProvider) {
+            gen.writeStartObject()
+            gen.writeStringField("id", event.id)
+            gen.writeStringField("pubkey", event.pubKey)
+            gen.writeNumberField("created_at", event.createdAt)
+            gen.writeNumberField("kind", event.kind)
+            gen.writeArrayFieldStart("tags")
+            event.tags.forEach { tag ->
+                gen.writeArray(tag.toTypedArray(), 0, tag.size)
+            }
+            gen.writeEndArray()
+            gen.writeStringField("content", event.content)
+            gen.writeStringField("sig", event.sig)
+            gen.writeEndObject()
+        }
+    }
+
+    private class GossipSerializer: StdSerializer<Gossip>(Gossip::class.java) {
+        override fun serialize(event: Gossip, gen: JsonGenerator, provider: SerializerProvider) {
+            gen.writeStartObject()
+            event.id?.let { gen.writeStringField("id", it) }
+            event.pubKey?.let { gen.writeStringField("pubkey", it) }
+            event.createdAt?.let { gen.writeNumberField("created_at", it) }
+            event.kind?.let { gen.writeNumberField("kind", it) }
+            event.tags?.let {
+                gen.writeArrayFieldStart("tags")
+                event.tags.forEach { tag ->
+                    gen.writeArray(tag.toTypedArray(), 0, tag.size)
+                }
+                gen.writeEndArray()
+            }
+            event.content?.let { gen.writeStringField("content", it)  }
+            gen.writeEndObject()
+        }
+    }
+
+    fun toJsonObject(): JsonNode {
+        val factory = mapper.nodeFactory
+
+        return factory.objectNode().apply {
+            put("id", id)
+            put("pubkey", pubKey)
+            put("created_at", createdAt)
+            put("kind", kind)
+            put(
+                "tags",
+                factory.arrayNode(tags.size).apply {
+                    tags.forEach { tag ->
+                        add(
+                            factory.arrayNode(tag.size).apply {
+                                tag.forEach { add(it) }
+                            }
+                        )
+                    }
+                }
+            )
+            put("content", content)
+            put("sig", sig)
+        }
+    }
+
+    companion object {
+        val mapper = jacksonObjectMapper()
+            .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
+            .registerModule(SimpleModule()
+                .addSerializer(Event::class.java, EventSerializer())
+                .addDeserializer(Event::class.java, EventDeserializer())
+                .addSerializer(Gossip::class.java, GossipSerializer())
+                .addDeserializer(Gossip::class.java, GossipDeserializer())
+                .addDeserializer(Response::class.java, ResponseDeserializer())
+                .addDeserializer(Request::class.java, RequestDeserializer())
+            )
+
+        fun fromJson(jsonObject: JsonNode): Event {
+            return EventFactory.create(
+                id = jsonObject.get("id").asText().intern(),
+                pubKey = jsonObject.get("pubkey").asText().intern(),
+                createdAt = jsonObject.get("created_at").asLong(),
+                kind = jsonObject.get("kind").asInt(),
+                tags = jsonObject.get("tags").map {
+                    it.mapNotNull { s -> if (s.isNull) null else s.asText().intern() }
+                },
+                content = jsonObject.get("content").asText(),
+                sig = jsonObject.get("sig").asText()
+            )
+        }
+
+        fun fromJson(json: String): Event = mapper.readValue(json, Event::class.java)
+        fun toJson(event: Event): String = mapper.writeValueAsString(event)
+
+        fun makeJsonForId(pubKey: HexKey, createdAt: Long, kind: Int, tags: List<List<String>>, content: String): String {
+            val factory = mapper.nodeFactory
+            val rawEvent = factory.arrayNode(6).apply {
+                add(0)
+                add(pubKey)
+                add(createdAt)
+                add(kind)
+                add(
+                    factory.arrayNode(tags.size).apply {
+                        tags.forEach { tag ->
+                            add(
+                                factory.arrayNode(tag.size).apply {
+                                    tag.forEach { add(it) }
+                                }
+                            )
+                        }
+                    }
+                )
+                add(content)
+            }
+
+            return mapper.writeValueAsString(rawEvent)
+        }
+
+        fun generateId(pubKey: HexKey, createdAt: Long, kind: Int, tags: List<List<String>>, content: String): ByteArray {
+            return CryptoUtils.sha256(makeJsonForId(pubKey, createdAt, kind, tags, content).toByteArray())
+        }
+
+        fun create(privateKey: ByteArray, kind: Int, tags: List<List<String>> = emptyList(), content: String = "", createdAt: Long = TimeUtils.now()): Event {
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = Companion.generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey).toHexKey()
+            return Event(id.toHexKey(), pubKey, createdAt, kind, tags, content, sig)
+        }
+    }
+}
+
+@Immutable
+interface AddressableEvent {
+    fun dTag(): String
+    fun address(): ATag
+}
+
+fun String.bytesUsedInMemory(): Int {
+    return (8 * ((((this.length) * 2) + 45) / 8))
+}
+

quartz/src/main/java/com/vitorpamplona/quartz/events/EventFactory.kt

@@ -0,0 +1,78 @@
+package com.vitorpamplona.quartz.events
+
+import com.vitorpamplona.quartz.encoders.toHexKey
+
+class EventFactory {
+    companion object {
+        fun create(
+            id: String,
+            pubKey: String,
+            createdAt: Long,
+            kind: Int,
+            tags: List<List<String>>,
+            content: String,
+            sig: String
+        ) = when (kind) {
+            AdvertisedRelayListEvent.kind -> AdvertisedRelayListEvent(id, pubKey, createdAt, tags, content, sig)
+            AppDefinitionEvent.kind -> AppDefinitionEvent(id, pubKey, createdAt, tags, content, sig)
+            AppRecommendationEvent.kind -> AppRecommendationEvent(id, pubKey, createdAt, tags, content, sig)
+            AudioTrackEvent.kind -> AudioTrackEvent(id, pubKey, createdAt, tags, content, sig)
+            BadgeAwardEvent.kind -> BadgeAwardEvent(id, pubKey, createdAt, tags, content, sig)
+            BadgeDefinitionEvent.kind -> BadgeDefinitionEvent(id, pubKey, createdAt, tags, content, sig)
+            BadgeProfilesEvent.kind -> BadgeProfilesEvent(id, pubKey, createdAt, tags, content, sig)
+            BookmarkListEvent.kind -> BookmarkListEvent(id, pubKey, createdAt, tags, content, sig)
+            ChannelCreateEvent.kind -> ChannelCreateEvent(id, pubKey, createdAt, tags, content, sig)
+            ChannelHideMessageEvent.kind -> ChannelHideMessageEvent(id, pubKey, createdAt, tags, content, sig)
+            ChannelMessageEvent.kind -> ChannelMessageEvent(id, pubKey, createdAt, tags, content, sig)
+            ChannelMetadataEvent.kind -> ChannelMetadataEvent(id, pubKey, createdAt, tags, content, sig)
+            ChannelMuteUserEvent.kind -> ChannelMuteUserEvent(id, pubKey, createdAt, tags, content, sig)
+            ChatMessageEvent.kind -> {
+                if (id.isBlank()) {
+                    val id = Event.generateId(pubKey, createdAt, kind, tags, content).toHexKey()
+                    ChatMessageEvent(id, pubKey, createdAt, tags, content, sig)
+                } else {
+                    ChatMessageEvent(id, pubKey, createdAt, tags, content, sig)
+                }
+            }
+            ClassifiedsEvent.kind -> ClassifiedsEvent(id, pubKey, createdAt, tags, content, sig)
+            CommunityDefinitionEvent.kind -> CommunityDefinitionEvent(id, pubKey, createdAt, tags, content, sig)
+            CommunityPostApprovalEvent.kind -> CommunityPostApprovalEvent(id, pubKey, createdAt, tags, content, sig)
+            ContactListEvent.kind -> ContactListEvent(id, pubKey, createdAt, tags, content, sig)
+            DeletionEvent.kind -> DeletionEvent(id, pubKey, createdAt, tags, content, sig)
+
+            // Will never happen.
+            // DirectMessageEvent.kind -> DirectMessageEvent(createdAt, tags, content)
+
+            EmojiPackEvent.kind -> EmojiPackEvent(id, pubKey, createdAt, tags, content, sig)
+            EmojiPackSelectionEvent.kind -> EmojiPackSelectionEvent(id, pubKey, createdAt, tags, content, sig)
+            SealedGossipEvent.kind -> SealedGossipEvent(id, pubKey, createdAt, tags, content, sig)
+
+            FileHeaderEvent.kind -> FileHeaderEvent(id, pubKey, createdAt, tags, content, sig)
+            FileStorageEvent.kind -> FileStorageEvent(id, pubKey, createdAt, tags, content, sig)
+            FileStorageHeaderEvent.kind -> FileStorageHeaderEvent(id, pubKey, createdAt, tags, content, sig)
+            GenericRepostEvent.kind -> GenericRepostEvent(id, pubKey, createdAt, tags, content, sig)
+            GiftWrapEvent.kind -> GiftWrapEvent(id, pubKey, createdAt, tags, content, sig)
+            HighlightEvent.kind -> HighlightEvent(id, pubKey, createdAt, tags, content, sig)
+            LiveActivitiesEvent.kind -> LiveActivitiesEvent(id, pubKey, createdAt, tags, content, sig)
+            LiveActivitiesChatMessageEvent.kind -> LiveActivitiesChatMessageEvent(id, pubKey, createdAt, tags, content, sig)
+            LnZapEvent.kind -> LnZapEvent(id, pubKey, createdAt, tags, content, sig)
+            LnZapPaymentRequestEvent.kind -> LnZapPaymentRequestEvent(id, pubKey, createdAt, tags, content, sig)
+            LnZapPaymentResponseEvent.kind -> LnZapPaymentResponseEvent(id, pubKey, createdAt, tags, content, sig)
+            LnZapRequestEvent.kind -> LnZapRequestEvent(id, pubKey, createdAt, tags, content, sig)
+            LongTextNoteEvent.kind -> LongTextNoteEvent(id, pubKey, createdAt, tags, content, sig)
+            MetadataEvent.kind -> MetadataEvent(id, pubKey, createdAt, tags, content, sig)
+            NNSEvent.kind -> NNSEvent(id, pubKey, createdAt, tags, content, sig)
+            PeopleListEvent.kind -> PeopleListEvent(id, pubKey, createdAt, tags, content, sig)
+            PinListEvent.kind -> PinListEvent(id, pubKey, createdAt, tags, content, sig)
+            PollNoteEvent.kind -> PollNoteEvent(id, pubKey, createdAt, tags, content, sig)
+            PrivateDmEvent.kind -> PrivateDmEvent(id, pubKey, createdAt, tags, content, sig)
+            ReactionEvent.kind -> ReactionEvent(id, pubKey, createdAt, tags, content, sig)
+            RecommendRelayEvent.kind -> RecommendRelayEvent(id, pubKey, createdAt, tags, content, sig)
+            RelaySetEvent.kind -> RelaySetEvent(id, pubKey, createdAt, tags, content, sig)
+            ReportEvent.kind -> ReportEvent(id, pubKey, createdAt, tags, content, sig)
+            RepostEvent.kind -> RepostEvent(id, pubKey, createdAt, tags, content, sig)
+            TextNoteEvent.kind -> TextNoteEvent(id, pubKey, createdAt, tags, content, sig)
+            else -> Event(id, pubKey, createdAt, kind, tags, content, sig)
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/EventInterface.kt

@@ -0,0 +1,70 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+import java.math.BigDecimal
+
+@Immutable
+interface EventInterface {
+    fun countMemory(): Long
+
+    fun id(): HexKey
+
+    fun pubKey(): HexKey
+
+    fun createdAt(): Long
+
+    fun kind(): Int
+
+    fun tags(): List<List<String>>
+
+    fun content(): String
+
+    fun sig(): HexKey
+
+    fun toJson(): String
+
+    fun checkSignature()
+
+    fun hasValidSignature(): Boolean
+
+    fun isTaggedUser(idHex: String): Boolean
+
+    fun isTaggedEvent(idHex: String): Boolean
+
+    fun isTaggedAddressableNote(idHex: String): Boolean
+    fun isTaggedAddressableNotes(idHexes: Set<String>): Boolean
+
+    fun isTaggedHash(hashtag: String): Boolean
+    fun isTaggedGeoHash(hashtag: String): Boolean
+
+    fun isTaggedHashes(hashtags: Set<String>): Boolean
+    fun isTaggedGeoHashes(hashtags: Set<String>): Boolean
+
+    fun firstIsTaggedHashes(hashtags: Set<String>): String?
+    fun firstIsTaggedAddressableNote(addressableNotes: Set<String>): String?
+
+    fun isTaggedAddressableKind(kind: Int): Boolean
+    fun getTagOfAddressableKind(kind: Int): ATag?
+
+    fun hashtags(): List<String>
+    fun geohashes(): List<String>
+
+    fun getReward(): BigDecimal?
+    fun getPoWRank(): Int
+    fun getGeoHash(): String?
+
+    fun zapAddress(): String?
+    fun isSensitive(): Boolean
+    fun subject(): String?
+    fun zapraiserAmount(): Long?
+
+    fun taggedAddresses(): List<ATag>
+    fun taggedUsers(): List<HexKey>
+    fun taggedEvents(): List<HexKey>
+    fun taggedUrls(): List<String>
+
+    fun taggedEmojis(): List<EmojiUrl>
+    fun matchTag1With(text: String): Boolean
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/FileHeaderEvent.kt

@@ -0,0 +1,87 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class FileHeaderEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    fun url() = tags.firstOrNull { it.size > 1 && it[0] == URL }?.get(1)
+    fun encryptionKey() = tags.firstOrNull { it.size > 2 && it[0] == ENCRYPTION_KEY }?.let { AESGCM(it[1], it[2]) }
+    fun mimeType() = tags.firstOrNull { it.size > 1 && it[0] == MIME_TYPE }?.get(1)
+    fun hash() = tags.firstOrNull { it.size > 1 && it[0] == HASH }?.get(1)
+    fun size() = tags.firstOrNull { it.size > 1 && it[0] == FILE_SIZE }?.get(1)
+    fun dimensions() = tags.firstOrNull { it.size > 1 && it[0] == DIMENSION }?.get(1)
+    fun magnetURI() = tags.firstOrNull { it.size > 1 && it[0] == MAGNET_URI }?.get(1)
+    fun torrentInfoHash() = tags.firstOrNull { it.size > 1 && it[0] == TORRENT_INFOHASH }?.get(1)
+    fun blurhash() = tags.firstOrNull { it.size > 1 && it[0] == BLUR_HASH }?.get(1)
+
+    fun hasUrl() = tags.any { it.size > 1 && it[0] == URL }
+
+    companion object {
+        const val kind = 1063
+
+        private const val URL = "url"
+        private const val ENCRYPTION_KEY = "aes-256-gcm"
+        private const val MIME_TYPE = "m"
+        private const val FILE_SIZE = "size"
+        private const val DIMENSION = "dim"
+        private const val HASH = "x"
+        private const val MAGNET_URI = "magnet"
+        private const val TORRENT_INFOHASH = "i"
+        private const val BLUR_HASH = "blurhash"
+
+        fun create(
+            url: String,
+            mimeType: String? = null,
+            description: String? = null,
+            hash: String? = null,
+            size: String? = null,
+            dimensions: String? = null,
+            blurhash: String? = null,
+            magnetURI: String? = null,
+            torrentInfoHash: String? = null,
+            encryptionKey: AESGCM? = null,
+            sensitiveContent: Boolean? = null,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): FileHeaderEvent {
+            val tags = listOfNotNull(
+                listOf(URL, url),
+                mimeType?.let { listOf(MIME_TYPE, mimeType) },
+                hash?.let { listOf(HASH, it) },
+                size?.let { listOf(FILE_SIZE, it) },
+                dimensions?.let { listOf(DIMENSION, it) },
+                blurhash?.let { listOf(BLUR_HASH, it) },
+                magnetURI?.let { listOf(MAGNET_URI, it) },
+                torrentInfoHash?.let { listOf(TORRENT_INFOHASH, it) },
+                encryptionKey?.let { listOf(ENCRYPTION_KEY, it.key, it.nonce) },
+                sensitiveContent?.let {
+                    if (it) {
+                        listOf("content-warning", "")
+                    } else {
+                        null
+                    }
+                }
+            )
+
+            val content = description ?: ""
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return FileHeaderEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}
+
+data class AESGCM(val key: String, val nonce: String)

quartz/src/main/java/com/vitorpamplona/quartz/events/FileStorageEvent.kt

@@ -0,0 +1,60 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+import java.util.Base64
+
+@Immutable
+class FileStorageEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    fun type() = tags.firstOrNull { it.size > 1 && it[0] == TYPE }?.get(1)
+    fun decryptKey() = tags.firstOrNull { it.size > 2 && it[0] == DECRYPT }?.let { AESGCM(it[1], it[2]) }
+
+    fun decode(): ByteArray? {
+        return try {
+            Base64.getDecoder().decode(content)
+        } catch (e: Exception) {
+            Log.e("FileStorageEvent", "Unable to decode base 64 ${e.message} $content")
+            null
+        }
+    }
+
+    companion object {
+        const val kind = 1064
+
+        private const val TYPE = "type"
+        private const val DECRYPT = "decrypt"
+
+        fun encode(bytes: ByteArray): String {
+            return Base64.getEncoder().encodeToString(bytes)
+        }
+
+        fun create(
+            mimeType: String,
+            data: ByteArray,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): FileStorageEvent {
+            val tags = listOfNotNull(
+                listOf(TYPE, mimeType)
+            )
+
+            val content = encode(data)
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return FileStorageEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/FileStorageHeaderEvent.kt

@@ -0,0 +1,83 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class FileStorageHeaderEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    fun dataEventId() = tags.firstOrNull { it.size > 1 && it[0] == "e" }?.get(1)
+
+    fun encryptionKey() = tags.firstOrNull { it.size > 2 && it[0] == ENCRYPTION_KEY }?.let { AESGCM(it[1], it[2]) }
+    fun mimeType() = tags.firstOrNull { it.size > 1 && it[0] == MIME_TYPE }?.get(1)
+    fun hash() = tags.firstOrNull { it.size > 1 && it[0] == HASH }?.get(1)
+    fun size() = tags.firstOrNull { it.size > 1 && it[0] == FILE_SIZE }?.get(1)
+    fun dimensions() = tags.firstOrNull { it.size > 1 && it[0] == DIMENSION }?.get(1)
+    fun magnetURI() = tags.firstOrNull { it.size > 1 && it[0] == MAGNET_URI }?.get(1)
+    fun torrentInfoHash() = tags.firstOrNull { it.size > 1 && it[0] == TORRENT_INFOHASH }?.get(1)
+    fun blurhash() = tags.firstOrNull { it.size > 1 && it[0] == BLUR_HASH }?.get(1)
+
+    companion object {
+        const val kind = 1065
+
+        private const val ENCRYPTION_KEY = "aes-256-gcm"
+        private const val MIME_TYPE = "m"
+        private const val FILE_SIZE = "size"
+        private const val DIMENSION = "dim"
+        private const val HASH = "x"
+        private const val MAGNET_URI = "magnet"
+        private const val TORRENT_INFOHASH = "i"
+        private const val BLUR_HASH = "blurhash"
+
+        fun create(
+            storageEvent: FileStorageEvent,
+            mimeType: String? = null,
+            description: String? = null,
+            hash: String? = null,
+            size: String? = null,
+            dimensions: String? = null,
+            blurhash: String? = null,
+            magnetURI: String? = null,
+            torrentInfoHash: String? = null,
+            encryptionKey: AESGCM? = null,
+            sensitiveContent: Boolean? = null,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): FileStorageHeaderEvent {
+            val tags = listOfNotNull(
+                listOf("e", storageEvent.id),
+                mimeType?.let { listOf(MIME_TYPE, mimeType) },
+                hash?.let { listOf(HASH, it) },
+                size?.let { listOf(FILE_SIZE, it) },
+                dimensions?.let { listOf(DIMENSION, it) },
+                blurhash?.let { listOf(BLUR_HASH, it) },
+                magnetURI?.let { listOf(MAGNET_URI, it) },
+                torrentInfoHash?.let { listOf(TORRENT_INFOHASH, it) },
+                encryptionKey?.let { listOf(ENCRYPTION_KEY, it.key, it.nonce) },
+                sensitiveContent?.let {
+                    if (it) {
+                        listOf("content-warning", "")
+                    } else {
+                        null
+                    }
+                }
+            )
+
+            val content = description ?: ""
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return FileStorageHeaderEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/GeneralListEvent.kt

@@ -0,0 +1,113 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.fasterxml.jackson.module.kotlin.readValue
+import com.vitorpamplona.quartz.encoders.hexToByteArray
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+abstract class GeneralListEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    kind: Int,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+    override fun dTag() = tags.filter { it.firstOrNull() == "d" }.mapNotNull { it.getOrNull(1) }.firstOrNull() ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun category() = dTag()
+    fun bookmarkedPosts() = taggedEvents()
+    fun bookmarkedPeople() = taggedUsers()
+
+    fun plainContent(privKey: ByteArray): String? {
+        if (content.isBlank()) return null
+
+        return try {
+            val sharedSecret = CryptoUtils.getSharedSecretNIP04(privKey, pubKey.hexToByteArray())
+
+            return CryptoUtils.decryptNIP04(content, sharedSecret)
+        } catch (e: Exception) {
+            Log.w("GeneralList", "Error decrypting the message ${e.message} for ${dTag()}")
+            null
+        }
+    }
+
+    @Transient
+    private var privateTagsCache: List<List<String>>? = null
+
+    fun privateTags(privKey: ByteArray): List<List<String>>? {
+        if (privateTagsCache != null) {
+            return privateTagsCache
+        }
+
+        privateTagsCache = try {
+            plainContent(privKey)?.let { mapper.readValue<List<List<String>>>(it) }
+        } catch (e: Throwable) {
+            Log.w("GeneralList", "Error parsing the JSON ${e.message}")
+            null
+        }
+        return privateTagsCache
+    }
+
+    fun privateTagsOrEmpty(privKey: ByteArray): List<List<String>> {
+        return privateTags(privKey) ?: emptyList()
+    }
+
+    fun privateTaggedUsers(privKey: ByteArray) = privateTags(privKey)?.filter { it.size > 1 && it[0] == "p" }?.map { it[1] }
+
+    fun privateHashtags(privKey: ByteArray) = privateTags(privKey)?.filter { it.size > 1 && it[0] == "t" }?.map { it[1] }
+    fun privateGeohashes(privKey: ByteArray) = privateTags(privKey)?.filter { it.size > 1 && it[0] == "g" }?.map { it[1] }
+    fun privateTaggedEvents(privKey: ByteArray) = privateTags(privKey)?.filter { it.size > 1 && it[0] == "e" }?.map { it[1] }
+    fun privateTaggedAddresses(privKey: ByteArray) = privateTags(privKey)?.filter { it.firstOrNull() == "a" }?.mapNotNull {
+        val aTagValue = it.getOrNull(1)
+        val relay = it.getOrNull(2)
+
+        if (aTagValue != null) ATag.parse(aTagValue, relay) else null
+    }
+
+    companion object {
+        fun createPrivateTags(
+            privEvents: List<String>? = null,
+            privUsers: List<String>? = null,
+            privAddresses: List<ATag>? = null,
+
+            privateKey: ByteArray,
+            pubKey: ByteArray
+        ): String {
+            val privTags = mutableListOf<List<String>>()
+            privEvents?.forEach {
+                privTags.add(listOf("e", it))
+            }
+            privUsers?.forEach {
+                privTags.add(listOf("p", it))
+            }
+            privAddresses?.forEach {
+                privTags.add(listOf("a", it.toTag()))
+            }
+            val msg = mapper.writeValueAsString(privTags)
+
+            return CryptoUtils.encryptNIP04(
+                msg,
+                privateKey,
+                pubKey
+            )
+        }
+
+        fun encryptTags(
+            privateTags: List<List<String>>? = null,
+            privateKey: ByteArray
+        ): String {
+            return CryptoUtils.encryptNIP04(
+                msg = mapper.writeValueAsString(privateTags),
+                privateKey = privateKey,
+                pubKey = CryptoUtils.pubkeyCreate(privateKey)
+            )
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/GenericRepostEvent.kt

@@ -0,0 +1,69 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class GenericRepostEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    fun boostedPost() = tags.filter { it.firstOrNull() == "e" }.mapNotNull { it.getOrNull(1) }
+    fun originalAuthor() = tags.filter { it.firstOrNull() == "p" }.mapNotNull { it.getOrNull(1) }
+
+    fun containedPost() = try {
+        fromJson(content)
+    } catch (e: Exception) {
+        null
+    }
+
+    companion object {
+        const val kind = 16
+
+        fun create(boostedPost: EventInterface, pubKey: HexKey, createdAt: Long = TimeUtils.now()): GenericRepostEvent {
+            val content = boostedPost.toJson()
+
+            val replyToPost = listOf("e", boostedPost.id())
+            val replyToAuthor = listOf("p", boostedPost.pubKey())
+
+            var tags: List<List<String>> = listOf(replyToPost, replyToAuthor)
+
+            if (boostedPost is AddressableEvent) {
+                tags = tags + listOf(listOf("a", boostedPost.address().toTag()))
+            }
+
+            tags = tags + listOf(listOf("k", "${boostedPost.kind()}"))
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            return GenericRepostEvent(id.toHexKey(), pubKey, createdAt, tags, content, "")
+        }
+
+        fun create(boostedPost: EventInterface, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): GenericRepostEvent {
+            val content = boostedPost.toJson()
+
+            val replyToPost = listOf("e", boostedPost.id())
+            val replyToAuthor = listOf("p", boostedPost.pubKey())
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            var tags: List<List<String>> = listOf(replyToPost, replyToAuthor)
+
+            if (boostedPost is AddressableEvent) {
+                tags = tags + listOf(listOf("a", boostedPost.address().toTag()))
+            }
+
+            tags = tags + listOf(listOf("k", "${boostedPost.kind()}"))
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return GenericRepostEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/GiftWrapEvent.kt

@@ -0,0 +1,85 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.hexToByteArray
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.crypto.Nip44Version
+import com.vitorpamplona.quartz.crypto.decodeNIP44
+import com.vitorpamplona.quartz.crypto.encodeNIP44
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class GiftWrapEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+    @Transient
+    private var cachedInnerEvent: Map<HexKey, Event?> = mapOf()
+
+    fun cachedGift(privKey: ByteArray): Event? {
+        val hex = privKey.toHexKey()
+        if (cachedInnerEvent.contains(hex)) return cachedInnerEvent[hex]
+
+        val myInnerEvent = unwrap(privKey = privKey)
+        cachedInnerEvent = cachedInnerEvent + Pair(hex, myInnerEvent)
+        return myInnerEvent
+    }
+
+    fun unwrap(privKey: ByteArray) = try {
+        plainContent(privKey)?.let { fromJson(it) }
+    } catch (e: Exception) {
+        // Log.e("UnwrapError", "Couldn't Decrypt the content", e)
+        null
+    }
+
+    private fun plainContent(privKey: ByteArray): String? {
+        if (content.isEmpty()) return null
+
+        return try {
+            val toDecrypt = decodeNIP44(content) ?: return null
+
+            return when (toDecrypt.v) {
+                Nip44Version.NIP04.versionCode -> CryptoUtils.decryptNIP04(toDecrypt, privKey, pubKey.hexToByteArray())
+                Nip44Version.NIP24.versionCode -> CryptoUtils.decryptNIP24(toDecrypt, privKey, pubKey.hexToByteArray())
+                else -> null
+            }
+        } catch (e: Exception) {
+            Log.w("GeneralList", "Error decrypting the message ${e.message}")
+            null
+        }
+    }
+
+    fun recipientPubKey() = tags.firstOrNull { it.size > 1 && it[0] == "p" }?.get(1)
+
+    companion object {
+        const val kind = 1059
+
+        fun create(
+            event: Event,
+            recipientPubKey: HexKey,
+            createdAt: Long = TimeUtils.randomWithinAWeek()
+        ): GiftWrapEvent {
+            val privateKey = CryptoUtils.privkeyCreate() // GiftWrap is always a random key
+            val sharedSecret = CryptoUtils.getSharedSecretNIP24(privateKey, recipientPubKey.hexToByteArray())
+
+            val content = encodeNIP44(
+                CryptoUtils.encryptNIP24(
+                    toJson(event),
+                    sharedSecret
+                )
+            )
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags = listOf(listOf("p", recipientPubKey))
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return GiftWrapEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/HTTPAuthorizationEvent.kt

@@ -0,0 +1,46 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class HTTPAuthorizationEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    companion object {
+        const val kind = 27235
+
+        fun create(
+            url: String,
+            method: String,
+            body: String? = null,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): HTTPAuthorizationEvent {
+            var hash = ""
+            body?.let {
+                hash = CryptoUtils.sha256(it.toByteArray()).toHexKey()
+            }
+
+            val tags = listOfNotNull(
+                listOf("u", url),
+                listOf("method", method),
+                listOf("payload", hash)
+            )
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, "")
+            val sig = CryptoUtils.sign(id, privateKey)
+            return HTTPAuthorizationEvent(id.toHexKey(), pubKey, createdAt, tags, "", sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/HighlightEvent.kt

@@ -0,0 +1,40 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class HighlightEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : BaseTextNoteEvent(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    fun inUrl() = taggedUrls().firstOrNull()
+    fun author() = taggedUsers().firstOrNull()
+    fun quote() = content
+
+    fun inPost() = taggedAddresses().firstOrNull()
+
+    companion object {
+        const val kind = 9802
+
+        fun create(
+            msg: String,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): HighlightEvent {
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags = mutableListOf<List<String>>()
+            val id = generateId(pubKey, createdAt, kind, tags, msg)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return HighlightEvent(id.toHexKey(), pubKey, createdAt, tags, msg, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/LiveActivitiesChatMessageEvent.kt

@@ -0,0 +1,87 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class LiveActivitiesChatMessageEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : BaseTextNoteEvent(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    private fun innerActivity() = tags.firstOrNull {
+        it.size > 3 && it[0] == "a" && it[3] == "root"
+    } ?: tags.firstOrNull {
+        it.size > 1 && it[0] == "a"
+    }
+
+    private fun activityHex() = innerActivity()?.let {
+        it.getOrNull(1)
+    }
+
+    fun activity() = innerActivity()?.let {
+        if (it.size > 1) {
+            val aTagValue = it[1]
+            val relay = it.getOrNull(2)
+
+            ATag.parse(aTagValue, relay)
+        } else {
+            null
+        }
+    }
+
+    override fun replyTos() = taggedEvents().minus(activityHex() ?: "")
+
+    companion object {
+        const val kind = 1311
+
+        fun create(
+            message: String,
+            activity: ATag,
+            replyTos: List<String>? = null,
+            mentions: List<String>? = null,
+            zapReceiver: String?,
+            pubKey: HexKey,
+            privateKey: ByteArray?,
+            createdAt: Long = TimeUtils.now(),
+            markAsSensitive: Boolean,
+            zapRaiserAmount: Long?,
+            geohash: String? = null
+        ): LiveActivitiesChatMessageEvent {
+            val content = message
+            val tags = mutableListOf(
+                listOf("a", activity.toTag(), "", "root")
+            )
+            replyTos?.forEach {
+                tags.add(listOf("e", it))
+            }
+            mentions?.forEach {
+                tags.add(listOf("p", it))
+            }
+            zapReceiver?.let {
+                tags.add(listOf("zap", it))
+            }
+            if (markAsSensitive) {
+                tags.add(listOf("content-warning", ""))
+            }
+            zapRaiserAmount?.let {
+                tags.add(listOf("zapraiser", "$it"))
+            }
+            geohash?.let {
+                tags.add(listOf("g", it))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = if (privateKey == null) null else CryptoUtils.sign(id, privateKey)
+            return LiveActivitiesChatMessageEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig?.toHexKey() ?: "")
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/LiveActivitiesEvent.kt

@@ -0,0 +1,61 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class LiveActivitiesEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+
+    override fun dTag() = tags.firstOrNull { it.size > 1 && it[0] == "d" }?.get(1) ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun title() = tags.firstOrNull { it.size > 1 && it[0] == "title" }?.get(1)
+    fun summary() = tags.firstOrNull { it.size > 1 && it[0] == "summary" }?.get(1)
+    fun image() = tags.firstOrNull { it.size > 1 && it[0] == "image" }?.get(1)
+    fun streaming() = tags.firstOrNull { it.size > 1 && it[0] == "streaming" }?.get(1)
+    fun starts() = tags.firstOrNull { it.size > 1 && it[0] == "starts" }?.get(1)?.toLongOrNull()
+    fun ends() = tags.firstOrNull { it.size > 1 && it[0] == "ends" }?.get(1)
+    fun status() = checkStatus(tags.firstOrNull { it.size > 1 && it[0] == "status" }?.get(1))
+    fun currentParticipants() = tags.firstOrNull { it.size > 1 && it[0] == "current_participants" }?.get(1)
+    fun totalParticipants() = tags.firstOrNull { it.size > 1 && it[0] == "total_participants" }?.get(1)
+
+    fun participants() = tags.filter { it.size > 1 && it[0] == "p" }.map { Participant(it[1], it.getOrNull(3)) }
+
+    fun checkStatus(eventStatus: String?): String? {
+        return if (eventStatus == STATUS_LIVE && createdAt < TimeUtils.eightHoursAgo()) {
+            STATUS_ENDED
+        } else {
+            eventStatus
+        }
+    }
+
+    companion object {
+        const val kind = 30311
+
+        const val STATUS_LIVE = "live"
+        const val STATUS_PLANNED = "planned"
+        const val STATUS_ENDED = "ended"
+
+        fun create(
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): LiveActivitiesEvent {
+            val tags = mutableListOf<List<String>>()
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, "")
+            val sig = CryptoUtils.sign(id, privateKey)
+            return LiveActivitiesEvent(id.toHexKey(), pubKey, createdAt, tags, "", sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/LnZapEvent.kt

@@ -0,0 +1,74 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.encoders.HexKey
+import com.vitorpamplona.quartz.encoders.LnInvoiceUtil
+
+@Immutable
+class LnZapEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : LnZapEventInterface, Event(id, pubKey, createdAt, kind, tags, content, sig) {
+    // This event is also kept in LocalCache (same object)
+    @Transient val zapRequest: LnZapRequestEvent?
+    override fun containedPost(): LnZapRequestEvent? = try {
+        description()?.ifBlank { null }?.let {
+            fromJson(it)
+        } as? LnZapRequestEvent
+    } catch (e: Exception) {
+        Log.e("LnZapEvent", "Failed to Parse Contained Post ${description()}", e)
+        null
+    }
+
+    init {
+        zapRequest = containedPost()
+    }
+
+    override fun zappedPost() = tags.filter { it.size > 1 && it[0] == "e" }.map { it[1] }
+
+    override fun zappedAuthor() = tags.filter { it.size > 1 && it[0] == "p" }.map { it[1] }
+
+    override fun zappedPollOption(): Int? = try {
+        zapRequest?.tags?.firstOrNull { it.size > 1 && it[0] == POLL_OPTION }?.get(1)?.toInt()
+    } catch (e: Exception) {
+        Log.e("LnZapEvent", "ZappedPollOption failed to parse", e)
+        null
+    }
+
+    override fun zappedRequestAuthor(): String? = zapRequest?.pubKey()
+
+    override fun amount() = amount
+
+    // Keeps this as a field because it's a heavier function used everywhere.
+    val amount by lazy {
+        try {
+            lnInvoice()?.let { LnInvoiceUtil.getAmountInSats(it) }
+        } catch (e: Exception) {
+            Log.e("LnZapEvent", "Failed to Parse LnInvoice ${description()}", e)
+            null
+        }
+    }
+    override fun content(): String {
+        return content
+    }
+
+    fun lnInvoice() = tags.firstOrNull { it.size > 1 && it[0] == "bolt11" }?.get(1)
+
+    private fun description() = tags.firstOrNull { it.size > 1 && it[0] == "description" }?.get(1)
+
+    companion object {
+        const val kind = 9735
+    }
+
+    enum class ZapType() {
+        PUBLIC,
+        PRIVATE,
+        ANONYMOUS,
+        NONZAP
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/LnZapEventInterface.kt

@@ -0,0 +1,20 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import java.math.BigDecimal
+
+@Immutable
+interface LnZapEventInterface : EventInterface {
+
+    fun zappedPost(): List<String>
+
+    fun zappedPollOption(): Int?
+
+    fun zappedAuthor(): List<String>
+
+    fun zappedRequestAuthor(): String?
+
+    fun amount(): BigDecimal?
+
+    fun containedPost(): Event?
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/LnZapPaymentRequestEvent.kt

@@ -0,0 +1,107 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.fasterxml.jackson.core.JsonParser
+import com.fasterxml.jackson.databind.DeserializationContext
+import com.fasterxml.jackson.databind.JsonNode
+import com.fasterxml.jackson.databind.deser.std.StdDeserializer
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.hexToByteArray
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class LnZapPaymentRequestEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    // Once one of an app user decrypts the payment, all users else can see it.
+    @Transient
+    private var lnInvoice: String? = null
+
+    fun walletServicePubKey() = tags.firstOrNull() { it.size > 1 && it[0] == "p" }?.get(1)
+
+    fun lnInvoice(privKey: ByteArray, pubkey: ByteArray): String? {
+        if (lnInvoice != null) {
+            return lnInvoice
+        }
+
+        return try {
+            val sharedSecret = CryptoUtils.getSharedSecretNIP04(privKey, pubkey)
+
+            val jsonText = CryptoUtils.decryptNIP04(content, sharedSecret)
+
+            val payInvoiceMethod = mapper.readValue(jsonText, Request::class.java)
+
+            lnInvoice = (payInvoiceMethod as? PayInvoiceMethod)?.params?.invoice
+
+            return lnInvoice
+        } catch (e: Exception) {
+            Log.w("BookmarkList", "Error decrypting the message ${e.message}")
+            null
+        }
+    }
+
+    companion object {
+        const val kind = 23194
+
+        fun create(
+            lnInvoice: String,
+            walletServicePubkey: String,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): LnZapPaymentRequestEvent {
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey)
+            val serializedRequest = mapper.writeValueAsString(PayInvoiceMethod.create(lnInvoice))
+
+            val content = CryptoUtils.encryptNIP04(
+                serializedRequest,
+                privateKey,
+                walletServicePubkey.hexToByteArray()
+            )
+
+            val tags = mutableListOf<List<String>>()
+            tags.add(listOf("p", walletServicePubkey))
+
+            val id = generateId(pubKey.toHexKey(), createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return LnZapPaymentRequestEvent(id.toHexKey(), pubKey.toHexKey(), createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}
+
+// REQUEST OBJECTS
+
+abstract class Request(var method: String? = null)
+
+// PayInvoice Call
+class PayInvoiceParams(var invoice: String? = null)
+
+class PayInvoiceMethod(var params: PayInvoiceParams? = null) : Request("pay_invoice") {
+
+    companion object {
+        fun create(bolt11: String): PayInvoiceMethod {
+            return PayInvoiceMethod(PayInvoiceParams(bolt11))
+        }
+    }
+}
+
+
+class RequestDeserializer : StdDeserializer<Request>(Request::class.java) {
+    override fun deserialize(jp: JsonParser, ctxt: DeserializationContext): Request? {
+        val jsonObject: JsonNode = jp.codec.readTree(jp)
+        val method = jsonObject.get("method")?.asText()
+
+        if (method == "pay_invoice") {
+            return jp.codec.treeToValue(jsonObject, PayInvoiceMethod::class.java)
+        }
+        return null
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/LnZapPaymentResponseEvent.kt

@@ -0,0 +1,132 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.fasterxml.jackson.annotation.JsonProperty
+import com.fasterxml.jackson.core.JsonParser
+import com.fasterxml.jackson.databind.DeserializationContext
+import com.fasterxml.jackson.databind.JsonNode
+import com.fasterxml.jackson.databind.deser.std.StdDeserializer
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class LnZapPaymentResponseEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    // Once one of an app user decrypts the payment, all users else can see it.
+    @Transient
+    private var response: Response? = null
+
+    fun requestAuthor() = tags.firstOrNull() { it.size > 1 && it[0] == "p" }?.get(1)
+    fun requestId() = tags.firstOrNull() { it.size > 1 && it[0] == "e" }?.get(1)
+
+    private fun decrypt(privKey: ByteArray, pubKey: ByteArray): String? {
+        return try {
+            val sharedSecret = CryptoUtils.getSharedSecretNIP04(privKey, pubKey)
+
+            val retVal = CryptoUtils.decryptNIP04(content, sharedSecret)
+
+            if (retVal.startsWith(PrivateDmEvent.nip18Advertisement)) {
+                retVal.substring(16)
+            } else {
+                retVal
+            }
+        } catch (e: Exception) {
+            Log.w("PrivateDM", "Error decrypting the message ${e.message}")
+            null
+        }
+    }
+
+    fun response(privKey: ByteArray, pubKey: ByteArray): Response? {
+        if (response != null) response
+
+        return try {
+            if (content.isNotEmpty()) {
+                val decrypted = decrypt(privKey, pubKey)
+                response = mapper.readValue(decrypted, Response::class.java)
+                response
+            } else {
+                null
+            }
+        } catch (e: Exception) {
+            Log.w("LnZapPaymentResponseEvent", "Can't parse content as a payment response: $content", e)
+            null
+        }
+    }
+
+    companion object {
+        const val kind = 23195
+    }
+}
+
+// RESPONSE OBJECTS
+abstract class Response(
+    @JsonProperty("result_type")
+    val resultType: String
+)
+
+// PayInvoice Call
+
+class PayInvoiceSuccessResponse(val result: PayInvoiceResultParams? = null) :
+    Response("pay_invoice") {
+    class PayInvoiceResultParams(val preimage: String)
+}
+
+class PayInvoiceErrorResponse(val error: PayInvoiceErrorParams? = null) :
+    Response("pay_invoice") {
+    class PayInvoiceErrorParams(val code: ErrorType?, val message: String?)
+
+    enum class ErrorType {
+        @JsonProperty(value = "RATE_LIMITED")
+        RATE_LIMITED, // The client is sending commands too fast. It should retry in a few seconds.
+        @JsonProperty(value = "NOT_IMPLEMENTED")
+        NOT_IMPLEMENTED, // The command is not known or is intentionally not implemented.
+        @JsonProperty(value = "INSUFFICIENT_BALANCE")
+        INSUFFICIENT_BALANCE, // The wallet does not have enough funds to cover a fee reserve or the payment amount.
+        @JsonProperty(value = "QUOTA_EXCEEDED")
+        QUOTA_EXCEEDED, // The wallet has exceeded its spending quota.
+        @JsonProperty(value = "RESTRICTED")
+        RESTRICTED, // This public key is not allowed to do this operation.
+        @JsonProperty(value = "UNAUTHORIZED")
+        UNAUTHORIZED, // This public key has no wallet connected.
+        @JsonProperty(value = "INTERNAL")
+        INTERNAL, // An internal error.
+        @JsonProperty(value = "OTHER")
+        OTHER // Other error.
+    }
+}
+
+
+class ResponseDeserializer : StdDeserializer<Response>(Response::class.java) {
+    override fun deserialize(jp: JsonParser, ctxt: DeserializationContext): Response? {
+        val jsonObject: JsonNode = jp.codec.readTree(jp)
+        val resultType = jsonObject.get("result_type")?.asText()
+
+        if (resultType == "pay_invoice") {
+            val result = jsonObject.get("result")
+            val error = jsonObject.get("error")
+            if (result != null) {
+                return jp.codec.treeToValue(jsonObject, PayInvoiceSuccessResponse::class.java)
+            }
+            if (error != null) {
+                return jp.codec.treeToValue(jsonObject, PayInvoiceErrorResponse::class.java)
+            }
+        } else {
+            // tries to guess
+            if (jsonObject.get("result")?.get("preimage") != null) {
+                return jp.codec.treeToValue(jsonObject, PayInvoiceSuccessResponse::class.java)
+            }
+            if (jsonObject.get("error")?.get("code") != null) {
+                return jp.codec.treeToValue(jsonObject, PayInvoiceErrorResponse::class.java)
+            }
+        }
+        return null
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/LnZapRequestEvent.kt

@@ -0,0 +1,184 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.*
+import com.vitorpamplona.quartz.encoders.Bech32
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+import com.vitorpamplona.quartz.encoders.hexToByteArray
+import com.vitorpamplona.quartz.encoders.toHexKey
+import java.nio.charset.Charset
+import java.security.SecureRandom
+import javax.crypto.BadPaddingException
+import javax.crypto.Cipher
+import javax.crypto.spec.IvParameterSpec
+import javax.crypto.spec.SecretKeySpec
+
+@Immutable
+class LnZapRequestEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    @Transient
+    private var privateZapEvent: Event? = null
+
+    fun zappedPost() = tags.filter { it.size > 1 && it[0] == "e" }.map { it[1] }
+
+    fun zappedAuthor() = tags.filter { it.size > 1 && it[0] == "p" }.map { it[1] }
+
+    fun isPrivateZap() = tags.any { t -> t.size >= 2 && t[0] == "anon" && t[1].isNotBlank() }
+
+    fun getPrivateZapEvent(loggedInUserPrivKey: ByteArray, pubKey: HexKey): Event? {
+        if (privateZapEvent != null) return privateZapEvent
+
+        val anonTag = tags.firstOrNull { t -> t.size >= 2 && t[0] == "anon" }
+        if (anonTag != null) {
+            val encnote = anonTag[1]
+            if (encnote.isNotBlank()) {
+                try {
+                    val note = decryptPrivateZapMessage(encnote, loggedInUserPrivKey, pubKey.hexToByteArray())
+                    val decryptedEvent = fromJson(note)
+                    if (decryptedEvent.kind == 9733) {
+                        privateZapEvent = decryptedEvent
+                        return privateZapEvent
+                    }
+                } catch (e: Exception) {
+                    e.printStackTrace()
+                }
+            }
+        }
+        return null
+    }
+
+    companion object {
+        const val kind = 9734
+
+        fun create(
+            originalNote: EventInterface,
+            relays: Set<String>,
+            privateKey: ByteArray,
+            pollOption: Int?,
+            message: String,
+            zapType: LnZapEvent.ZapType,
+            createdAt: Long = TimeUtils.now()
+        ): LnZapRequestEvent {
+            var content = message
+            var privkey = privateKey
+            var pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            var tags = listOf(
+                listOf("e", originalNote.id()),
+                listOf("p", originalNote.pubKey()),
+                listOf("relays") + relays
+            )
+            if (originalNote is AddressableEvent) {
+                tags = tags + listOf(listOf("a", originalNote.address().toTag()))
+            }
+            if (pollOption != null && pollOption >= 0) {
+                tags = tags + listOf(listOf(POLL_OPTION, pollOption.toString()))
+            }
+            if (zapType == LnZapEvent.ZapType.ANONYMOUS) {
+                tags = tags + listOf(listOf("anon", ""))
+                privkey = CryptoUtils.privkeyCreate()
+                pubKey = CryptoUtils.pubkeyCreate(privkey).toHexKey()
+            } else if (zapType == LnZapEvent.ZapType.PRIVATE) {
+                var encryptionPrivateKey = createEncryptionPrivateKey(privateKey.toHexKey(), originalNote.id(), createdAt)
+                var noteJson = (create(privkey, 9733, listOf(tags[0], tags[1]), message)).toJson()
+                var encryptedContent = encryptPrivateZapMessage(noteJson, encryptionPrivateKey, originalNote.pubKey().hexToByteArray())
+                tags = tags + listOf(listOf("anon", encryptedContent))
+                content = "" // make sure public content is empty, as the content is encrypted
+                privkey = encryptionPrivateKey // sign event with generated privkey
+                pubKey = CryptoUtils.pubkeyCreate(encryptionPrivateKey).toHexKey() // updated event with according pubkey
+            }
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privkey)
+            return LnZapRequestEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+
+        fun create(
+            userHex: String,
+            relays: Set<String>,
+            privateKey: ByteArray,
+            message: String,
+            zapType: LnZapEvent.ZapType,
+            createdAt: Long = TimeUtils.now()
+        ): LnZapRequestEvent {
+            var content = message
+            var privkey = privateKey
+            var pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            var tags = listOf(
+                listOf("p", userHex),
+                listOf("relays") + relays
+            )
+            if (zapType == LnZapEvent.ZapType.ANONYMOUS) {
+                privkey = CryptoUtils.privkeyCreate()
+                pubKey = CryptoUtils.pubkeyCreate(privkey).toHexKey()
+                tags = tags + listOf(listOf("anon", ""))
+            } else if (zapType == LnZapEvent.ZapType.PRIVATE) {
+                var encryptionPrivateKey = createEncryptionPrivateKey(privateKey.toHexKey(), userHex, createdAt)
+                var noteJson = (create(privkey, 9733, listOf(tags[0], tags[1]), message)).toJson()
+                var encryptedContent = encryptPrivateZapMessage(noteJson, encryptionPrivateKey, userHex.hexToByteArray())
+                tags = tags + listOf(listOf("anon", encryptedContent))
+                content = ""
+                privkey = encryptionPrivateKey
+                pubKey = CryptoUtils.pubkeyCreate(encryptionPrivateKey).toHexKey()
+            }
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privkey)
+            return LnZapRequestEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+
+        fun createEncryptionPrivateKey(privkey: String, id: String, createdAt: Long): ByteArray {
+            var str = privkey + id + createdAt.toString()
+            var strbyte = str.toByteArray(Charset.forName("utf-8"))
+            return CryptoUtils.sha256(strbyte)
+        }
+
+        private fun encryptPrivateZapMessage(msg: String, privkey: ByteArray, pubkey: ByteArray): String {
+            var sharedSecret = CryptoUtils.getSharedSecretNIP04(privkey, pubkey)
+            val iv = ByteArray(16)
+            SecureRandom().nextBytes(iv)
+
+            val keySpec = SecretKeySpec(sharedSecret, "AES")
+            val ivSpec = IvParameterSpec(iv)
+
+            var utf8message = msg.toByteArray(Charset.forName("utf-8"))
+            val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
+            cipher.init(Cipher.ENCRYPT_MODE, keySpec, ivSpec)
+            val encryptedMsg = cipher.doFinal(utf8message)
+
+            val encryptedMsgBech32 = Bech32.encode("pzap", Bech32.eight2five(encryptedMsg), Bech32.Encoding.Bech32)
+            val ivBech32 = Bech32.encode("iv", Bech32.eight2five(iv), Bech32.Encoding.Bech32)
+
+            return encryptedMsgBech32 + "_" + ivBech32
+        }
+
+        private fun decryptPrivateZapMessage(msg: String, privkey: ByteArray, pubkey: ByteArray): String {
+            var sharedSecret = CryptoUtils.getSharedSecretNIP04(privkey, pubkey)
+            if (sharedSecret.size != 16 && sharedSecret.size != 32) {
+                throw IllegalArgumentException("Invalid shared secret size")
+            }
+            val parts = msg.split("_")
+            if (parts.size != 2) {
+                throw IllegalArgumentException("Invalid message format")
+            }
+            val iv = parts[1].run { Bech32.decode(this).second }
+            val encryptedMsg = parts.first().run { Bech32.decode(this).second }
+            val encryptedBytes = Bech32.five2eight(encryptedMsg, 0)
+            val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
+            cipher.init(Cipher.DECRYPT_MODE, SecretKeySpec(sharedSecret, "AES"), IvParameterSpec(
+                Bech32.five2eight(iv, 0)))
+
+            try {
+                val decryptedMsgBytes = cipher.doFinal(encryptedBytes)
+                return String(decryptedMsgBytes)
+            } catch (ex: BadPaddingException) {
+                throw IllegalArgumentException("Bad padding: ${ex.message}")
+            }
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/LongTextNoteEvent.kt

@@ -0,0 +1,50 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class LongTextNoteEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : BaseTextNoteEvent(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+    override fun dTag() = tags.filter { it.firstOrNull() == "d" }.mapNotNull { it.getOrNull(1) }.firstOrNull() ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun topics() = tags.filter { it.firstOrNull() == "t" }.mapNotNull { it.getOrNull(1) }
+    fun title() = tags.filter { it.firstOrNull() == "title" }.mapNotNull { it.getOrNull(1) }.firstOrNull()
+    fun image() = tags.filter { it.firstOrNull() == "image" }.mapNotNull { it.getOrNull(1) }.firstOrNull()
+    fun summary() = tags.filter { it.firstOrNull() == "summary" }.mapNotNull { it.getOrNull(1) }.firstOrNull()
+
+    fun publishedAt() = try {
+        tags.firstOrNull { it.size > 1 && it[0] == "published_at" }?.get(1)?.toLongOrNull()
+    } catch (_: Exception) {
+        null
+    }
+
+    companion object {
+        const val kind = 30023
+
+        fun create(msg: String, replyTos: List<String>?, mentions: List<String>?, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): LongTextNoteEvent {
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags = mutableListOf<List<String>>()
+            replyTos?.forEach {
+                tags.add(listOf("e", it))
+            }
+            mentions?.forEach {
+                tags.add(listOf("p", it))
+            }
+            val id = generateId(pubKey, createdAt, kind, tags, msg)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return LongTextNoteEvent(id.toHexKey(), pubKey, createdAt, tags, msg, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/MetadataEvent.kt

@@ -0,0 +1,164 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Stable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+import java.io.ByteArrayInputStream
+
+@Stable
+abstract class IdentityClaim(
+    val identity: String,
+    val proof: String
+) {
+    abstract fun toProofUrl(): String
+    abstract fun platform(): String
+
+    fun platformIdentity() = "${platform()}:$identity"
+
+    companion object {
+        fun create(platformIdentity: String, proof: String): IdentityClaim? {
+            val (platform, identity) = platformIdentity.split(':')
+
+            return when (platform.lowercase()) {
+                GitHubIdentity.platform -> GitHubIdentity(identity, proof)
+                TwitterIdentity.platform -> TwitterIdentity(identity, proof)
+                TelegramIdentity.platform -> TelegramIdentity(identity, proof)
+                MastodonIdentity.platform -> MastodonIdentity(identity, proof)
+                else -> throw IllegalArgumentException("Platform $platform not supported")
+            }
+        }
+    }
+}
+
+class GitHubIdentity(
+    identity: String,
+    proof: String
+) : IdentityClaim(identity, proof) {
+    override fun toProofUrl() = "https://gist.github.com/$identity/$proof"
+
+    override fun platform() = platform
+
+    companion object {
+        val platform = "github"
+
+        fun parseProofUrl(proofUrl: String): GitHubIdentity? {
+            return try {
+                if (proofUrl.isBlank()) return null
+                val path = proofUrl.removePrefix("https://gist.github.com/").split("?")[0].split("/")
+
+                GitHubIdentity(path[0], path[1])
+            } catch (e: Exception) {
+                null
+            }
+        }
+    }
+}
+
+class TwitterIdentity(
+    identity: String,
+    proof: String
+) : IdentityClaim(identity, proof) {
+    override fun toProofUrl() = "https://twitter.com/$identity/status/$proof"
+
+    override fun platform() = platform
+
+    companion object {
+        val platform = "twitter"
+
+        fun parseProofUrl(proofUrl: String): TwitterIdentity? {
+            return try {
+                if (proofUrl.isBlank()) return null
+                val path = proofUrl.removePrefix("https://twitter.com/").split("?")[0].split("/")
+
+                TwitterIdentity(path[0], path[2])
+            } catch (e: Exception) {
+                null
+            }
+        }
+    }
+}
+
+class TelegramIdentity(
+    identity: String,
+    proof: String
+) : IdentityClaim(identity, proof) {
+    override fun toProofUrl() = "https://t.me/$proof"
+
+    override fun platform() = platform
+
+    companion object {
+        val platform = "telegram"
+    }
+}
+
+class MastodonIdentity(
+    identity: String,
+    proof: String
+) : IdentityClaim(identity, proof) {
+    override fun toProofUrl() = "https://$identity/$proof"
+
+    override fun platform() = platform
+
+    companion object {
+        val platform = "mastodon"
+
+        fun parseProofUrl(proofUrl: String): MastodonIdentity? {
+            return try {
+                if (proofUrl.isBlank()) return null
+                val path = proofUrl.removePrefix("https://").split("?")[0].split("/")
+
+                return MastodonIdentity("${path[0]}/${path[1]}", path[2])
+            } catch (e: Exception) {
+                null
+            }
+        }
+    }
+}
+
+class MetadataEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+    fun contactMetaData() = try {
+        mapper.readValue(
+            ByteArrayInputStream(content.toByteArray(Charsets.UTF_8)),
+            UserMetadata::class.java
+        )
+    } catch (e: Exception) {
+        // e.printStackTrace()
+        Log.w("MT", "Content Parse Error: ${e.localizedMessage} $content")
+        null
+    }
+
+    fun identityClaims() = tags.filter { it.firstOrNull() == "i" }.mapNotNull {
+        try {
+            IdentityClaim.create(it.get(1), it.get(2))
+        } catch (e: Exception) {
+            Log.e("MetadataEvent", "Can't parse identity [${it.joinToString { "," }}]", e)
+            null
+        }
+    }
+
+    companion object {
+        const val kind = 0
+
+        fun create(contactMetaData: String, identities: List<IdentityClaim>, pubKey: HexKey, privateKey: ByteArray?, createdAt: Long = TimeUtils.now()): MetadataEvent {
+            val tags = mutableListOf<List<String>>()
+
+            identities.forEach {
+                tags.add(listOf("i", it.platformIdentity(), it.proof))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, contactMetaData)
+            val sig = if (privateKey == null) null else CryptoUtils.sign(id, privateKey)
+            return MetadataEvent(id.toHexKey(), pubKey, createdAt, tags, contactMetaData, sig?.toHexKey() ?: "")
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/MuteListEvent.kt

@@ -0,0 +1,113 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.fasterxml.jackson.module.kotlin.readValue
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.hexToByteArray
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class MuteListEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+    override fun dTag() = tags.filter { it.firstOrNull() == "d" }.mapNotNull { it.getOrNull(1) }.firstOrNull() ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun plainContent(privKey: ByteArray): String? {
+        return try {
+            val sharedSecret = CryptoUtils.getSharedSecretNIP04(privKey, pubKey.hexToByteArray())
+
+            return CryptoUtils.decryptNIP04(content, sharedSecret)
+        } catch (e: Exception) {
+            Log.w("BookmarkList", "Error decrypting the message ${e.message}")
+            null
+        }
+    }
+
+    @Transient
+    private var privateTagsCache: List<List<String>>? = null
+
+    fun privateTags(privKey: ByteArray): List<List<String>>? {
+        if (privateTagsCache != null) {
+            return privateTagsCache
+        }
+
+        privateTagsCache = try {
+            plainContent(privKey)?.let { mapper.readValue<List<List<String>>>(it) }
+        } catch (e: Throwable) {
+            Log.w("BookmarkList", "Error parsing the JSON ${e.message}")
+            null
+        }
+        return privateTagsCache
+    }
+
+    fun privateTaggedUsers(privKey: ByteArray) = privateTags(privKey)?.filter { it.firstOrNull() == "p" }?.mapNotNull { it.getOrNull(1) }
+    fun privateTaggedEvents(privKey: ByteArray) = privateTags(privKey)?.filter { it.firstOrNull() == "e" }?.mapNotNull { it.getOrNull(1) }
+    fun privateTaggedAddresses(privKey: ByteArray) = privateTags(privKey)?.filter { it.firstOrNull() == "a" }?.mapNotNull {
+        val aTagValue = it.getOrNull(1)
+        val relay = it.getOrNull(2)
+
+        if (aTagValue != null) ATag.parse(aTagValue, relay) else null
+    }
+
+    companion object {
+        const val kind = 10000
+
+        fun create(
+            events: List<String>? = null,
+            users: List<String>? = null,
+            addresses: List<ATag>? = null,
+
+            privEvents: List<String>? = null,
+            privUsers: List<String>? = null,
+            privAddresses: List<ATag>? = null,
+
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): MuteListEvent {
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey)
+
+            val privTags = mutableListOf<List<String>>()
+            privEvents?.forEach {
+                privTags.add(listOf("e", it))
+            }
+            privUsers?.forEach {
+                privTags.add(listOf("p", it))
+            }
+            privAddresses?.forEach {
+                privTags.add(listOf("a", it.toTag()))
+            }
+            val msg = mapper.writeValueAsString(privTags)
+
+            val content = CryptoUtils.encryptNIP04(
+                msg,
+                privateKey,
+                pubKey
+            )
+
+            val tags = mutableListOf<List<String>>()
+            events?.forEach {
+                tags.add(listOf("e", it))
+            }
+            users?.forEach {
+                tags.add(listOf("p", it))
+            }
+            addresses?.forEach {
+                tags.add(listOf("a", it.toTag()))
+            }
+
+            val id = generateId(pubKey.toHexKey(), createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return MuteListEvent(id.toHexKey(), pubKey.toHexKey(), createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/NIP24Factory.kt

@@ -0,0 +1,88 @@
+package com.vitorpamplona.quartz.events
+
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+class NIP24Factory {
+    fun createMsgNIP24(
+        msg: String,
+        to: List<HexKey>,
+        from: ByteArray,
+        subject: String? = null,
+        replyTos: List<String>? = null,
+        mentions: List<String>? = null,
+        zapReceiver: String? = null,
+        markAsSensitive: Boolean = false,
+        zapRaiserAmount: Long? = null,
+        geohash: String? = null
+    ): List<GiftWrapEvent> {
+        val senderPublicKey = CryptoUtils.pubkeyCreate(from).toHexKey()
+
+        val senderMessage = ChatMessageEvent.create(
+            msg = msg,
+            to = to,
+            privateKey = from,
+            subject = subject,
+            replyTos = replyTos,
+            mentions = mentions,
+            zapReceiver = zapReceiver,
+            markAsSensitive = markAsSensitive,
+            zapRaiserAmount = zapRaiserAmount,
+            geohash = geohash
+        )
+
+        return to.plus(senderPublicKey).map {
+            GiftWrapEvent.create(
+                event = SealedGossipEvent.create(
+                    event = senderMessage,
+                    encryptTo = it,
+                    privateKey = from
+                ),
+                recipientPubKey = it
+            )
+        }
+    }
+
+    fun createReactionWithinGroup(content: String, originalNote: EventInterface, to: List<HexKey>, from: ByteArray): List<GiftWrapEvent> {
+        val senderPublicKey = CryptoUtils.pubkeyCreate(from).toHexKey()
+
+        val senderReaction = ReactionEvent.create(
+            content,
+            originalNote,
+            from
+        )
+
+        return to.plus(senderPublicKey).map {
+            GiftWrapEvent.create(
+                event = SealedGossipEvent.create(
+                    event = senderReaction,
+                    encryptTo = it,
+                    privateKey = from
+                ),
+                recipientPubKey = it
+            )
+        }
+    }
+
+    fun createReactionWithinGroup(emojiUrl: EmojiUrl, originalNote: EventInterface, to: List<HexKey>, from: ByteArray): List<GiftWrapEvent> {
+        val senderPublicKey = CryptoUtils.pubkeyCreate(from).toHexKey()
+
+        val senderReaction = ReactionEvent.create(
+            emojiUrl,
+            originalNote,
+            from
+        )
+
+        return to.plus(senderPublicKey).map {
+            GiftWrapEvent.create(
+                event = SealedGossipEvent.create(
+                    event = senderReaction,
+                    encryptTo = it,
+                    privateKey = from
+                ),
+                recipientPubKey = it
+            )
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/NNSEvent.kt

@@ -0,0 +1,41 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class NNSEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+
+    override fun dTag() = tags.firstOrNull { it.size > 1 && it[0] == "d" }?.get(1) ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun ip4() = tags.firstOrNull { it.size > 1 && it[0] == "ip4" }?.get(1)
+    fun ip6() = tags.firstOrNull { it.size > 1 && it[0] == "ip6" }?.get(1)
+    fun version() = tags.firstOrNull { it.size > 1 && it[0] == "version" }?.get(1)
+
+    companion object {
+        const val kind = 30053
+
+        fun create(
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): NNSEvent {
+            val tags = mutableListOf<List<String>>()
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, "")
+            val sig = CryptoUtils.sign(id, privateKey)
+            return NNSEvent(id.toHexKey(), pubKey, createdAt, tags, "", sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/PeopleListEvent.kt

@@ -0,0 +1,150 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+import kotlinx.collections.immutable.ImmutableSet
+import kotlinx.collections.immutable.persistentSetOf
+import kotlinx.collections.immutable.toImmutableSet
+
+@Immutable
+class PeopleListEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : GeneralListEvent(id, pubKey, createdAt, kind, tags, content, sig) {
+    var publicAndPrivateUserCache: ImmutableSet<HexKey>? = null
+
+    fun publicAndPrivateUsers(privateKey: ByteArray?): ImmutableSet<HexKey> {
+        publicAndPrivateUserCache?.let {
+            return it
+        }
+
+        val privateUserList = privateKey?.let {
+            privateTagsOrEmpty(privKey = it).filter { it.size > 1 && it[0] == "p" }.map { it[1] }.toSet()
+        } ?: emptySet()
+        val publicUserList = tags.filter { it.size > 1 && it[0] == "p" }.map { it[1] }.toSet()
+
+        publicAndPrivateUserCache = (privateUserList + publicUserList).toImmutableSet()
+
+        return publicAndPrivateUserCache ?: persistentSetOf()
+    }
+
+    fun isTaggedUser(idHex: String, isPrivate: Boolean, privateKey: ByteArray): Boolean {
+        return if (isPrivate) {
+            privateTagsOrEmpty(privKey = privateKey).any { it.size > 1 && it[0] == "p" && it[1] == idHex }
+        } else {
+            isTaggedUser(idHex)
+        }
+    }
+
+    companion object {
+        const val kind = 30000
+        const val blockList = "mute"
+
+        fun createListWithUser(name: String, pubKeyHex: String, isPrivate: Boolean, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): PeopleListEvent {
+            return if (isPrivate) {
+                create(
+                    content = encryptTags(listOf(listOf("p", pubKeyHex)), privateKey),
+                    tags = listOf(listOf("d", name)),
+                    privateKey = privateKey,
+                    createdAt = createdAt
+                )
+            } else {
+                create(
+                    content = "",
+                    tags = listOf(listOf("d", name), listOf("p", pubKeyHex)),
+                    privateKey = privateKey,
+                    createdAt = createdAt
+                )
+            }
+        }
+
+        fun addUsers(earlierVersion: PeopleListEvent, listPubKeyHex: List<String>, isPrivate: Boolean, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): PeopleListEvent {
+            return if (isPrivate) {
+                create(
+                    content = encryptTags(
+                        privateTags = earlierVersion.privateTagsOrEmpty(privKey = privateKey).plus(
+                            listPubKeyHex.map {
+                                listOf("p", it)
+                            }
+                        ),
+                        privateKey = privateKey
+                    ),
+                    tags = earlierVersion.tags,
+                    privateKey = privateKey,
+                    createdAt = createdAt
+                )
+            } else {
+                create(
+                    content = earlierVersion.content,
+                    tags = earlierVersion.tags.plus(
+                        listPubKeyHex.map {
+                            listOf("p", it)
+                        }
+                    ),
+                    privateKey = privateKey,
+                    createdAt = createdAt
+                )
+            }
+        }
+
+        fun addUser(earlierVersion: PeopleListEvent, pubKeyHex: String, isPrivate: Boolean, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): PeopleListEvent {
+            if (earlierVersion.isTaggedUser(pubKeyHex, isPrivate, privateKey)) return earlierVersion
+
+            return if (isPrivate) {
+                create(
+                    content = encryptTags(
+                        privateTags = earlierVersion.privateTagsOrEmpty(privKey = privateKey).plus(element = listOf("p", pubKeyHex)),
+                        privateKey = privateKey
+                    ),
+                    tags = earlierVersion.tags,
+                    privateKey = privateKey,
+                    createdAt = createdAt
+                )
+            } else {
+                create(
+                    content = earlierVersion.content,
+                    tags = earlierVersion.tags.plus(element = listOf("p", pubKeyHex)),
+                    privateKey = privateKey,
+                    createdAt = createdAt
+                )
+            }
+        }
+
+        fun removeUser(earlierVersion: PeopleListEvent, pubKeyHex: String, isPrivate: Boolean, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): PeopleListEvent {
+            if (!earlierVersion.isTaggedUser(pubKeyHex, isPrivate, privateKey)) return earlierVersion
+
+            return if (isPrivate) {
+                create(
+                    content = encryptTags(
+                        privateTags = earlierVersion.privateTagsOrEmpty(privKey = privateKey).filter { it.size > 1 && it[1] != pubKeyHex },
+                        privateKey = privateKey
+                    ),
+                    tags = earlierVersion.tags.filter { it.size > 1 && it[1] != pubKeyHex },
+                    privateKey = privateKey,
+                    createdAt = createdAt
+                )
+            } else {
+                create(
+                    content = earlierVersion.content,
+                    tags = earlierVersion.tags.filter { it.size > 1 && it[1] != pubKeyHex },
+                    privateKey = privateKey,
+                    createdAt = createdAt
+                )
+            }
+        }
+
+        fun create(content: String, tags: List<List<String>>, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): PeopleListEvent {
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return PeopleListEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/PinListEvent.kt

@@ -0,0 +1,44 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class PinListEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+
+    override fun dTag() = tags.firstOrNull { it.size > 1 && it[0] == "d" }?.get(1) ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun pins() = tags.filter { it.size > 1 && it[0] == "pin" }.map { it[1] }
+
+    companion object {
+        const val kind = 33888
+
+        fun create(
+            pins: List<String>,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): PinListEvent {
+            val tags = mutableListOf<List<String>>()
+            pins.forEach {
+                tags.add(listOf("pin", it))
+            }
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, "")
+            val sig = CryptoUtils.sign(id, privateKey)
+            return PinListEvent(id.toHexKey(), pubKey, createdAt, tags, "", sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/PollNoteEvent.kt

@@ -0,0 +1,120 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+const val POLL_OPTION = "poll_option"
+const val VALUE_MAXIMUM = "value_maximum"
+const val VALUE_MINIMUM = "value_minimum"
+const val CONSENSUS_THRESHOLD = "consensus_threshold"
+const val CLOSED_AT = "closed_at"
+
+@Immutable
+class PollNoteEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    // ots: String?, TODO implement OTS: https://github.com/opentimestamps/java-opentimestamps
+    content: String,
+    sig: HexKey
+) : BaseTextNoteEvent(id, pubKey, createdAt, kind, tags, content, sig) {
+    fun pollOptions() =
+        tags.filter { it.size > 2 && it[0] == POLL_OPTION }
+            .associate { it[1].toInt() to it[2] }
+
+    fun getTagInt(property: String): Int? {
+        val number = tags.firstOrNull() { it.size > 1 && it[0] == property }?.get(1)
+
+        return if (number.isNullOrBlank() || number == "null") {
+            null
+        } else {
+            number.toInt()
+        }
+    }
+
+    companion object {
+        const val kind = 6969
+
+        fun create(
+            msg: String,
+            replyTos: List<String>?,
+            mentions: List<String>?,
+            addresses: List<ATag>?,
+            pubKey: HexKey,
+            privateKey: ByteArray?,
+            createdAt: Long = TimeUtils.now(),
+            pollOptions: Map<Int, String>,
+            valueMaximum: Int?,
+            valueMinimum: Int?,
+            consensusThreshold: Int?,
+            closedAt: Int?,
+            zapReceiver: String?,
+            markAsSensitive: Boolean,
+            zapRaiserAmount: Long?,
+            geohash: String? = null
+        ): PollNoteEvent {
+            val tags = mutableListOf<List<String>>()
+            replyTos?.forEach {
+                tags.add(listOf("e", it))
+            }
+            mentions?.forEach {
+                tags.add(listOf("p", it))
+            }
+            addresses?.forEach {
+                tags.add(listOf("a", it.toTag()))
+            }
+            pollOptions.forEach { poll_op ->
+                tags.add(listOf(POLL_OPTION, poll_op.key.toString(), poll_op.value))
+            }
+            tags.add(listOf(VALUE_MAXIMUM, valueMaximum.toString()))
+            tags.add(listOf(VALUE_MINIMUM, valueMinimum.toString()))
+            tags.add(listOf(CONSENSUS_THRESHOLD, consensusThreshold.toString()))
+            tags.add(listOf(CLOSED_AT, closedAt.toString()))
+
+            if (zapReceiver != null) {
+                tags.add(listOf("zap", zapReceiver))
+            }
+            if (markAsSensitive) {
+                tags.add(listOf("content-warning", ""))
+            }
+            zapRaiserAmount?.let {
+                tags.add(listOf("zapraiser", "$it"))
+            }
+            geohash?.let {
+                tags.add(listOf("g", it))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, msg)
+            val sig = if (privateKey == null) null else CryptoUtils.sign(id, privateKey)
+            return PollNoteEvent(id.toHexKey(), pubKey, createdAt, tags, msg, sig?.toHexKey() ?: "")
+        }
+    }
+}
+
+/*
+{
+  "id": <32-bytes lowercase hex-encoded sha256 of the serialized event data>
+  "pubkey": <32-bytes lowercase hex-encoded public key of the event creator>,
+  "created_at": <unix timestamp in seconds>,
+  "kind": 6969,
+  "tags": [
+    ["e", <32-bytes hex of the id of the poll event>, <primary poll host relay URL>],
+    ["p", <32-bytes hex of the key>, <primary poll host relay URL>],
+    ["poll_option", "0", "poll option 0 description string"],
+    ["poll_option", "1", "poll option 1 description string"],
+    ["poll_option", "n", "poll option <n> description string"],
+    ["value_maximum", "maximum satoshi value for inclusion in tally"],
+    ["value_minimum", "minimum satoshi value for inclusion in tally"],
+    ["consensus_threshold", "required percentage to attain consensus <0..100>"],
+    ["closed_at", "unix timestamp in seconds"],
+  ],
+  "ots": <base64-encoded OTS file data>
+  "content": <primary poll description string>,
+  "sig": <64-bytes hex of the signature of the sha256 hash of the serialized event data, which is the same as the "id" field>
+}
+ */

quartz/src/main/java/com/vitorpamplona/quartz/events/PrivateDmEvent.kt

@@ -0,0 +1,131 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+import com.vitorpamplona.quartz.encoders.HexValidator
+import com.vitorpamplona.quartz.encoders.Hex
+import kotlinx.collections.immutable.persistentSetOf
+
+@Immutable
+class PrivateDmEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), ChatroomKeyable {
+    /**
+     * This may or may not be the actual recipient's pub key. The event is intended to look like a
+     * nip-04 EncryptedDmEvent but may omit the recipient, too. This value can be queried and used
+     * for initial messages.
+     */
+    private fun recipientPubKey() = tags.firstOrNull { it.size > 1 && it[0] == "p" }?.get(1)
+
+    fun recipientPubKeyBytes() = recipientPubKey()?.runCatching { Hex.decode(this) }?.getOrNull()
+
+    fun verifiedRecipientPubKey(): HexKey? {
+        val recipient = recipientPubKey()
+        return if (HexValidator.isHex(recipient)) {
+            recipient
+        } else {
+            null
+        }
+    }
+
+    fun talkingWith(oneSideHex: String): HexKey {
+        return if (pubKey == oneSideHex) verifiedRecipientPubKey() ?: pubKey else pubKey
+    }
+
+    override fun chatroomKey(toRemove: String): ChatroomKey {
+        return ChatroomKey(persistentSetOf(talkingWith(toRemove)))
+    }
+
+    /**
+     * To be fully compatible with nip-04, we read e-tags that are in violation to nip-18.
+     *
+     * Nip-18 messages should refer to other events by inline references in the content like
+     * `[](e/c06f795e1234a9a1aecc731d768d4f3ca73e80031734767067c82d67ce82e506).
+     */
+    fun replyTo() = tags.firstOrNull { it.size > 1 && it[0] == "e" }?.get(1)
+
+    fun with(pubkeyHex: String): Boolean {
+        return pubkeyHex == pubKey ||
+            tags.any { it.size > 1 && it[0] == "p" && it[1] == pubkeyHex }
+    }
+
+    fun plainContent(privKey: ByteArray, pubKey: ByteArray): String? {
+        return try {
+            val sharedSecret = CryptoUtils.getSharedSecretNIP04(privKey, pubKey)
+
+            val retVal = CryptoUtils.decryptNIP04(content, sharedSecret)
+
+            if (retVal.startsWith(nip18Advertisement)) {
+                retVal.substring(16)
+            } else {
+                retVal
+            }
+        } catch (e: Exception) {
+            Log.w("PrivateDM", "Error decrypting the message ${e.message}")
+            null
+        }
+    }
+
+    companion object {
+        const val kind = 4
+
+        const val nip18Advertisement = "[//]: # (nip18)\n"
+
+        fun create(
+            recipientPubKey: ByteArray,
+            msg: String,
+            replyTos: List<String>? = null,
+            mentions: List<String>? = null,
+            zapReceiver: String?,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now(),
+            publishedRecipientPubKey: ByteArray? = null,
+            advertiseNip18: Boolean = true,
+            markAsSensitive: Boolean,
+            zapRaiserAmount: Long?,
+            geohash: String? = null
+        ): PrivateDmEvent {
+            val content = CryptoUtils.encryptNIP04(
+                if (advertiseNip18) { nip18Advertisement } else { "" } + msg,
+                privateKey,
+                recipientPubKey
+            )
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags = mutableListOf<List<String>>()
+            publishedRecipientPubKey?.let {
+                tags.add(listOf("p", publishedRecipientPubKey.toHexKey()))
+            }
+            replyTos?.forEach {
+                tags.add(listOf("e", it))
+            }
+            mentions?.forEach {
+                tags.add(listOf("p", it))
+            }
+            zapReceiver?.let {
+                tags.add(listOf("zap", it))
+            }
+            if (markAsSensitive) {
+                tags.add(listOf("content-warning", ""))
+            }
+            zapRaiserAmount?.let {
+                tags.add(listOf("zapraiser", "$it"))
+            }
+            geohash?.let {
+                tags.add(listOf("g", it))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return PrivateDmEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/ReactionEvent.kt

@@ -0,0 +1,92 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class ReactionEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    fun originalPost() = tags.filter { it.size > 1 && it[0] == "e" }.map { it[1] }
+    fun originalAuthor() = tags.filter { it.size > 1 && it[0] == "p" }.map { it[1] }
+
+    companion object {
+        const val kind = 7
+
+        fun createWarning(originalNote: EventInterface, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ReactionEvent {
+            return create("\u26A0\uFE0F", originalNote, privateKey, createdAt)
+        }
+
+        fun createLike(originalNote: EventInterface, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ReactionEvent {
+            return create("+", originalNote, privateKey, createdAt)
+        }
+
+        fun create(content: String, originalNote: EventInterface, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ReactionEvent {
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+
+            var tags = listOf(listOf("e", originalNote.id()), listOf("p", originalNote.pubKey()))
+            if (originalNote is AddressableEvent) {
+                tags = tags + listOf(listOf("a", originalNote.address().toTag()))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return ReactionEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+
+        fun create(content: String, originalNote: EventInterface, pubKey: HexKey, createdAt: Long = TimeUtils.now()): ReactionEvent {
+            var tags = listOf(listOf("e", originalNote.id()), listOf("p", originalNote.pubKey()))
+            if (originalNote is AddressableEvent) {
+                tags = tags + listOf(listOf("a", originalNote.address().toTag()))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            return ReactionEvent(id.toHexKey(), pubKey, createdAt, tags, content, "")
+        }
+
+        fun create(emojiUrl: EmojiUrl, originalNote: EventInterface, pubKey: HexKey, createdAt: Long = TimeUtils.now()): ReactionEvent {
+            val content = ":${emojiUrl.code}:"
+
+            var tags = listOf(
+                listOf("e", originalNote.id()),
+                listOf("p", originalNote.pubKey()),
+                listOf("emoji", emojiUrl.code, emojiUrl.url)
+            )
+
+            if (originalNote is AddressableEvent) {
+                tags = tags + listOf(listOf("a", originalNote.address().toTag()))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            return ReactionEvent(id.toHexKey(), pubKey, createdAt, tags, content, "")
+        }
+
+        fun create(emojiUrl: EmojiUrl, originalNote: EventInterface, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ReactionEvent {
+            val content = ":${emojiUrl.code}:"
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+
+            var tags = listOf(
+                listOf("e", originalNote.id()),
+                listOf("p", originalNote.pubKey()),
+                listOf("emoji", emojiUrl.code, emojiUrl.url)
+            )
+
+            if (originalNote is AddressableEvent) {
+                tags = tags + listOf(listOf("a", originalNote.address().toTag()))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return ReactionEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/RecommendRelayEvent.kt

@@ -0,0 +1,34 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+import java.net.URI
+
+@Immutable
+class RecommendRelayEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    fun relay() = URI.create(content.trim())
+
+    companion object {
+        const val kind = 2
+
+        fun create(relay: URI, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): RecommendRelayEvent {
+            val content = relay.toString()
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags = listOf<List<String>>()
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return RecommendRelayEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/RelayAuthEvent.kt

@@ -0,0 +1,36 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class RelayAuthEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+    fun relay() = tags.firstOrNull() { it.size > 1 && it[0] == "relay" }?.get(1)
+    fun challenge() = tags.firstOrNull() { it.size > 1 && it[0] == "challenge" }?.get(1)
+
+    companion object {
+        const val kind = 22242
+
+        fun create(relay: String, challenge: String, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): RelayAuthEvent {
+            val content = ""
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags = listOf(
+                listOf("relay", relay),
+                listOf("challenge", challenge)
+            )
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return RelayAuthEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/RelaySetEvent.kt

@@ -0,0 +1,45 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class RelaySetEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig), AddressableEvent {
+
+    override fun dTag() = tags.firstOrNull { it.size > 1 && it[0] == "d" }?.get(1) ?: ""
+    override fun address() = ATag(kind, pubKey, dTag(), null)
+
+    fun relays() = tags.filter { it.size > 1 && it[0] == "r" }.map { it[1] }
+    fun description() = tags.firstOrNull() { it.size > 1 && it[0] == "description" }?.get(1)
+
+    companion object {
+        const val kind = 30022
+
+        fun create(
+            relays: List<String>,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): RelaySetEvent {
+            val tags = mutableListOf<List<String>>()
+            relays.forEach {
+                tags.add(listOf("r", it))
+            }
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, "")
+            val sig = CryptoUtils.sign(id, privateKey)
+            return RelaySetEvent(id.toHexKey(), pubKey, createdAt, tags, "", sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/ReportEvent.kt

@@ -0,0 +1,99 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+data class ReportedKey(val key: String, val reportType: ReportEvent.ReportType)
+
+// NIP 56 event.
+@Immutable
+class ReportEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    private fun defaultReportType(): ReportType {
+        // Works with old and new structures for report.
+        var reportType = tags.filter { it.firstOrNull() == "report" }.mapNotNull { it.getOrNull(1) }.map { ReportType.valueOf(it.uppercase()) }.firstOrNull()
+        if (reportType == null) {
+            reportType = tags.mapNotNull { it.getOrNull(2) }.map { ReportType.valueOf(it.uppercase()) }.firstOrNull()
+        }
+        if (reportType == null) {
+            reportType = ReportType.SPAM
+        }
+        return reportType
+    }
+
+    fun reportedPost() = tags
+        .filter { it.size > 1 && it[0] == "e" }
+        .map {
+            ReportedKey(
+                it[1],
+                it.getOrNull(2)?.uppercase()?.let { it1 -> ReportType.valueOf(it1) } ?: defaultReportType()
+            )
+        }
+
+    fun reportedAuthor() = tags
+        .filter { it.size > 1 && it[0] == "p" }
+        .map {
+            ReportedKey(
+                it[1],
+                it.getOrNull(2)?.uppercase()?.let { it1 -> ReportType.valueOf(it1) } ?: defaultReportType()
+            )
+        }
+
+    companion object {
+        const val kind = 1984
+
+        fun create(
+            reportedPost: EventInterface,
+            type: ReportType,
+            privateKey: ByteArray,
+            content: String = "",
+            createdAt: Long = TimeUtils.now()
+        ): ReportEvent {
+            val reportPostTag = listOf("e", reportedPost.id(), type.name.lowercase())
+            val reportAuthorTag = listOf("p", reportedPost.pubKey(), type.name.lowercase())
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            var tags: List<List<String>> = listOf(reportPostTag, reportAuthorTag)
+
+            if (reportedPost is AddressableEvent) {
+                tags = tags + listOf(listOf("a", reportedPost.address().toTag()))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return ReportEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+
+        fun create(reportedUser: String, type: ReportType, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): ReportEvent {
+            val content = ""
+
+            val reportAuthorTag = listOf("p", reportedUser, type.name.lowercase())
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags: List<List<String>> = listOf(reportAuthorTag)
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return ReportEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+
+    enum class ReportType() {
+        EXPLICIT, // Not used anymore.
+        ILLEGAL,
+        SPAM,
+        IMPERSONATION,
+        NUDITY,
+        PROFANITY
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/RepostEvent.kt

@@ -0,0 +1,65 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class RepostEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    fun boostedPost() = taggedEvents()
+    fun originalAuthor() = taggedUsers()
+
+    fun containedPost() = try {
+        fromJson(content)
+    } catch (e: Exception) {
+        null
+    }
+
+    companion object {
+        const val kind = 6
+
+        fun create(boostedPost: EventInterface, pubKey: HexKey, createdAt: Long = TimeUtils.now()): RepostEvent {
+            val content = boostedPost.toJson()
+
+            val replyToPost = listOf("e", boostedPost.id())
+            val replyToAuthor = listOf("p", boostedPost.pubKey())
+
+            var tags: List<List<String>> = listOf(replyToPost, replyToAuthor)
+
+            if (boostedPost is AddressableEvent) {
+                tags = tags + listOf(listOf("a", boostedPost.address().toTag()))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            return RepostEvent(id.toHexKey(), pubKey, createdAt, tags, content, "")
+        }
+
+        fun create(boostedPost: EventInterface, privateKey: ByteArray, createdAt: Long = TimeUtils.now()): RepostEvent {
+            val content = boostedPost.toJson()
+
+            val replyToPost = listOf("e", boostedPost.id())
+            val replyToAuthor = listOf("p", boostedPost.pubKey())
+
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            var tags: List<List<String>> = listOf(replyToPost, replyToAuthor)
+
+            if (boostedPost is AddressableEvent) {
+                tags = tags + listOf(listOf("a", boostedPost.address().toTag()))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return RepostEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/SealedGossipEvent.kt

@@ -0,0 +1,127 @@
+package com.vitorpamplona.quartz.events
+
+import android.util.Log
+import androidx.compose.runtime.Immutable
+import com.fasterxml.jackson.annotation.JsonProperty
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.hexToByteArray
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.crypto.Nip44Version
+import com.vitorpamplona.quartz.crypto.decodeNIP44
+import com.vitorpamplona.quartz.crypto.encodeNIP44
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class SealedGossipEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+    @Transient
+    private var cachedInnerEvent: Map<HexKey, Event?> = mapOf()
+
+    fun cachedGossip(privKey: ByteArray): Event? {
+        val hex = privKey.toHexKey()
+        if (cachedInnerEvent.contains(hex)) return cachedInnerEvent[hex]
+
+        val gossip = unseal(privKey = privKey)
+        val event = gossip?.mergeWith(this)
+        cachedInnerEvent = cachedInnerEvent + Pair(hex, event)
+        return event
+    }
+
+    fun unseal(privKey: ByteArray): Gossip? = try {
+        plainContent(privKey)?.let { Gossip.fromJson(it) }
+    } catch (e: Exception) {
+        Log.w("GossipEvent", "Fail to decrypt or parse Gossip", e)
+        null
+    }
+
+    private fun plainContent(privKey: ByteArray): String? {
+        if (content.isEmpty()) return null
+
+        return try {
+            val toDecrypt = decodeNIP44(content) ?: return null
+
+            return when (toDecrypt.v) {
+                Nip44Version.NIP04.versionCode -> CryptoUtils.decryptNIP04(toDecrypt, privKey, pubKey.hexToByteArray())
+                Nip44Version.NIP24.versionCode -> CryptoUtils.decryptNIP24(toDecrypt, privKey, pubKey.hexToByteArray())
+                else -> null
+            }
+        } catch (e: Exception) {
+            Log.w("GossipEvent", "Error decrypting the message ${e.message}")
+            null
+        }
+    }
+
+    companion object {
+        const val kind = 13
+
+        fun create(
+            event: Event,
+            encryptTo: HexKey,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): SealedGossipEvent {
+            val gossip = Gossip.create(event)
+            return create(gossip, encryptTo, privateKey, createdAt)
+        }
+
+        fun create(
+            gossip: Gossip,
+            encryptTo: HexKey,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.randomWithinAWeek()
+        ): SealedGossipEvent {
+            val sharedSecret = CryptoUtils.getSharedSecretNIP24(privateKey, encryptTo.hexToByteArray())
+
+            val content = encodeNIP44(
+                CryptoUtils.encryptNIP24(
+                    Gossip.toJson(gossip),
+                    sharedSecret
+                )
+            )
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val tags = listOf<List<String>>()
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return SealedGossipEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}
+
+class Gossip(
+    val id: HexKey?,
+    @JsonProperty("pubkey")
+    val pubKey: HexKey?,
+    @JsonProperty("created_at")
+    val createdAt: Long?,
+    val kind: Int?,
+    val tags: List<List<String>>?,
+    val content: String?
+) {
+    fun mergeWith(event: SealedGossipEvent): Event {
+        val newPubKey = pubKey?.ifBlank { null } ?: event.pubKey
+        val newCreatedAt = if (createdAt != null && createdAt > 1000) createdAt else event.createdAt
+        val newKind = kind ?: -1
+        val newTags = (tags ?: emptyList()).plus(event.tags)
+        val newContent = content ?: ""
+        val newID = id?.ifBlank { null } ?: Event.generateId(newPubKey, newCreatedAt, newKind, newTags, newContent).toHexKey()
+        val sig = ""
+
+        return EventFactory.create(newID, newPubKey, newCreatedAt, newKind, newTags, newContent, sig)
+    }
+
+    companion object {
+        fun fromJson(json: String): Gossip = Event.mapper.readValue(json, Gossip::class.java)
+        fun toJson(event: Gossip): String = Event.mapper.writeValueAsString(event)
+
+        fun create(event: Event): Gossip {
+            return Gossip(event.id, event.pubKey, event.createdAt, event.kind, event.tags, event.content)
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/TextNoteEvent.kt

@@ -0,0 +1,107 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.linkedin.urls.detection.UrlDetector
+import com.linkedin.urls.detection.UrlDetectorOptions
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class TextNoteEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : BaseTextNoteEvent(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    fun root() = tags.firstOrNull() { it.size > 3 && it[3] == "root" }?.get(1)
+
+    companion object {
+        const val kind = 1
+
+        fun create(
+            msg: String,
+            replyTos: List<String>?,
+            mentions: List<String>?,
+            addresses: List<ATag>?,
+            extraTags: List<String>?,
+            zapReceiver: String?,
+            markAsSensitive: Boolean,
+            zapRaiserAmount: Long?,
+            replyingTo: String?,
+            root: String?,
+            directMentions: Set<HexKey>,
+            geohash: String? = null,
+            pubKey: HexKey,
+            privateKey: ByteArray?,
+            createdAt: Long = TimeUtils.now()
+        ): TextNoteEvent {
+            val tags = mutableListOf<List<String>>()
+            replyTos?.forEach {
+                if (it == replyingTo) {
+                    tags.add(listOf("e", it, "", "reply"))
+                } else if (it == root) {
+                    tags.add(listOf("e", it, "", "root"))
+                } else if (it in directMentions) {
+                    tags.add(listOf("e", it, "", "mention"))
+                } else {
+                    tags.add(listOf("e", it))
+                }
+            }
+            mentions?.forEach {
+                if (it in directMentions) {
+                    tags.add(listOf("p", it, "", "mention"))
+                } else {
+                    tags.add(listOf("p", it))
+                }
+            }
+            addresses?.forEach {
+                val aTag = it.toTag()
+                if (aTag == replyingTo) {
+                    tags.add(listOf("a", aTag, "", "reply"))
+                } else if (aTag == root) {
+                    tags.add(listOf("a", aTag, "", "root"))
+                } else if (aTag in directMentions) {
+                    tags.add(listOf("a", aTag, "", "mention"))
+                } else {
+                    tags.add(listOf("a", aTag))
+                }
+            }
+            findHashtags(msg).forEach {
+                tags.add(listOf("t", it))
+                tags.add(listOf("t", it.lowercase()))
+            }
+            extraTags?.forEach {
+                tags.add(listOf("t", it))
+            }
+            zapReceiver?.let {
+                tags.add(listOf("zap", it))
+            }
+            findURLs(msg).forEach {
+                tags.add(listOf("r", it))
+            }
+            if (markAsSensitive) {
+                tags.add(listOf("content-warning", ""))
+            }
+            zapRaiserAmount?.let {
+                tags.add(listOf("zapraiser", "$it"))
+            }
+            geohash?.let {
+                tags.add(listOf("g", it))
+            }
+
+            val id = generateId(pubKey, createdAt, kind, tags, msg)
+            val sig = if (privateKey == null) null else CryptoUtils.sign(id, privateKey)
+            return TextNoteEvent(id.toHexKey(), pubKey, createdAt, tags, msg, sig?.toHexKey() ?: "")
+        }
+    }
+}
+
+fun findURLs(text: String): List<String> {
+    return UrlDetector(text, UrlDetectorOptions.Default).detect().map { it.originalUrl }
+}

quartz/src/main/java/com/vitorpamplona/quartz/utils/TimeUtils.kt

@@ -0,0 +1,20 @@
+package com.vitorpamplona.quartz.utils
+
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+
+object TimeUtils {
+    const val oneMinute = 60
+    const val fiveMinutes = 5 * oneMinute
+    const val oneHour = 60 * oneMinute
+    const val eightHours = 8 * oneHour
+    const val oneDay = 24 * oneHour
+    const val oneWeek = 7 * oneDay
+
+    fun now() = System.currentTimeMillis() / 1000
+    fun fiveMinutesAgo() = now() - fiveMinutes
+    fun oneHourAgo() = now() - oneHour
+    fun oneDayAgo() = now() - oneDay
+    fun eightHoursAgo() = now() - eightHours
+    fun oneWeekAgo() = now() - oneWeek
+    fun randomWithinAWeek() = System.currentTimeMillis() / 1000 - CryptoUtils.randomInt(oneWeek)
+}