feat: add attestations package to quartz experimental

Implement the Attestations NIP with four event types:
- AttestationEvent (31871, addressable) - validity claims about other events
- AttestationRequestEvent (31872, addressable) - request attestation from attestors
- AttestorRecommendationEvent (31873, addressable) - recommend attestors for kinds
- AttestorProficiencyEvent (11871, replaceable) - declare verification proficiency

Each event follows Quartz's tag-per-file pattern with TagArrayExt and
TagArrayBuilderExt for reading/building tags.

https://claude.ai/code/session_01UswHRVTNqn1ToU4P4XDh2V

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/attestation/AttestationEvent.kt

@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.attestation
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.AttestationStatus
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.Validity
+import com.vitorpamplona.quartz.nip01Core.core.BaseAddressableEvent
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip01Core.tags.dTag.dTag
+import com.vitorpamplona.quartz.nip31Alts.alt
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+@Immutable
+class AttestationEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : BaseAddressableEvent(id, pubKey, createdAt, KIND, tags, content, sig) {
+    fun validity() = tags.validity()
+
+    fun status() = tags.status()
+
+    fun validFrom() = tags.validFrom()
+
+    fun validTo() = tags.validTo()
+
+    fun request() = tags.request()
+
+    fun isRevoked() = status() == AttestationStatus.REVOKED
+
+    companion object {
+        const val KIND = 31871
+        const val ALT_DESCRIPTION = "Attestation"
+
+        fun build(
+            dTagId: String,
+            content: String = "",
+            validity: Validity? = null,
+            status: AttestationStatus? = null,
+            validFrom: Long? = null,
+            validTo: Long? = null,
+            requestAddress: String? = null,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<AttestationEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, content, createdAt) {
+            alt(ALT_DESCRIPTION)
+            dTag(dTagId)
+            validity?.let { validity(it) }
+            status?.let { status(it) }
+            validFrom?.let { validFrom(it) }
+            validTo?.let { validTo(it) }
+            requestAddress?.let { request(it) }
+            initializer()
+        }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/attestation/TagArrayBuilderExt.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.attestation
+
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.AttestationStatus
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.RequestTag
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.StatusTag
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.ValidFromTag
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.ValidToTag
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.Validity
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.ValidityTag
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+
+fun TagArrayBuilder<AttestationEvent>.validity(validity: Validity) = addUnique(ValidityTag.assemble(validity))
+
+fun TagArrayBuilder<AttestationEvent>.status(status: AttestationStatus) = addUnique(StatusTag.assemble(status))
+
+fun TagArrayBuilder<AttestationEvent>.validFrom(timestamp: Long) = addUnique(ValidFromTag.assemble(timestamp))
+
+fun TagArrayBuilder<AttestationEvent>.validTo(timestamp: Long) = addUnique(ValidToTag.assemble(timestamp))
+
+fun TagArrayBuilder<AttestationEvent>.request(requestAddress: String) = addUnique(RequestTag.assemble(requestAddress))

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/attestation/TagArrayExt.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.attestation
+
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.RequestTag
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.StatusTag
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.ValidFromTag
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.ValidToTag
+import com.vitorpamplona.quartz.experimental.attestations.attestation.tags.ValidityTag
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+
+fun TagArray.validity() = firstNotNullOfOrNull(ValidityTag::parse)
+
+fun TagArray.status() = firstNotNullOfOrNull(StatusTag::parse)
+
+fun TagArray.validFrom() = firstNotNullOfOrNull(ValidFromTag::parse)
+
+fun TagArray.validTo() = firstNotNullOfOrNull(ValidToTag::parse)
+
+fun TagArray.request() = firstNotNullOfOrNull(RequestTag::parse)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/attestation/tags/RequestTag.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.attestation.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+class RequestTag {
+    companion object {
+        const val TAG_NAME = "request"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): String? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+            return tag[1]
+        }
+
+        fun assemble(requestAddress: String) = arrayOf(TAG_NAME, requestAddress)
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/attestation/tags/StatusTag.kt

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.attestation.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+enum class AttestationStatus(
+    val code: String,
+) {
+    ACCEPTED("accepted"),
+    REJECTED("rejected"),
+    VERIFYING("verifying"),
+    VERIFIED("verified"),
+    REVOKED("revoked"),
+}
+
+class StatusTag {
+    companion object {
+        const val TAG_NAME = "s"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): AttestationStatus? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+
+            return when (tag[1]) {
+                AttestationStatus.ACCEPTED.code -> AttestationStatus.ACCEPTED
+                AttestationStatus.REJECTED.code -> AttestationStatus.REJECTED
+                AttestationStatus.VERIFYING.code -> AttestationStatus.VERIFYING
+                AttestationStatus.VERIFIED.code -> AttestationStatus.VERIFIED
+                AttestationStatus.REVOKED.code -> AttestationStatus.REVOKED
+                else -> null
+            }
+        }
+
+        fun assemble(status: AttestationStatus) = arrayOf(TAG_NAME, status.code)
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/attestation/tags/ValidFromTag.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.attestation.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+class ValidFromTag {
+    companion object {
+        const val TAG_NAME = "valid_from"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): Long? {
+            ensure(tag.has(1) && tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+            return tag[1].toLongOrNull()
+        }
+
+        fun assemble(time: Long) = arrayOf(TAG_NAME, time.toString())
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/attestation/tags/ValidToTag.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.attestation.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+class ValidToTag {
+    companion object {
+        const val TAG_NAME = "valid_to"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): Long? {
+            ensure(tag.has(1) && tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+            return tag[1].toLongOrNull()
+        }
+
+        fun assemble(time: Long) = arrayOf(TAG_NAME, time.toString())
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/attestation/tags/ValidityTag.kt

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.attestation.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+enum class Validity(
+    val code: String,
+) {
+    VALID("valid"),
+    INVALID("invalid"),
+}
+
+class ValidityTag {
+    companion object {
+        const val TAG_NAME = "v"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): Validity? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+
+            return when (tag[1]) {
+                Validity.VALID.code -> Validity.VALID
+                Validity.INVALID.code -> Validity.INVALID
+                else -> null
+            }
+        }
+
+        fun assemble(validity: Validity) = arrayOf(TAG_NAME, validity.code)
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/proficiency/AttestorProficiencyEvent.kt

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.proficiency
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.nip01Core.core.BaseReplaceableEvent
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.Kind
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip31Alts.alt
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+@Immutable
+class AttestorProficiencyEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : BaseReplaceableEvent(id, pubKey, createdAt, KIND, tags, content, sig) {
+    fun kinds() = tags.kinds()
+
+    fun description() = tags.description()
+
+    companion object {
+        const val KIND = 11871
+        const val ALT_DESCRIPTION = "Attestor Proficiency Declaration"
+
+        fun build(
+            kinds: List<Kind>,
+            description: String? = null,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<AttestorProficiencyEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, "", createdAt) {
+            alt(ALT_DESCRIPTION)
+            kinds(kinds)
+            description?.let { desc(it) }
+            initializer()
+        }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/proficiency/TagArrayBuilderExt.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.proficiency
+
+import com.vitorpamplona.quartz.experimental.attestations.recommendation.tags.DescriptionTag
+import com.vitorpamplona.quartz.experimental.attestations.recommendation.tags.KindTag
+import com.vitorpamplona.quartz.nip01Core.core.Kind
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+
+fun TagArrayBuilder<AttestorProficiencyEvent>.kinds(kinds: List<Kind>) = addAll(KindTag.assemble(kinds))
+
+fun TagArrayBuilder<AttestorProficiencyEvent>.desc(description: String) = addUnique(DescriptionTag.assemble(description))

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/proficiency/TagArrayExt.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.proficiency
+
+import com.vitorpamplona.quartz.experimental.attestations.recommendation.tags.DescriptionTag
+import com.vitorpamplona.quartz.experimental.attestations.recommendation.tags.KindTag
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+
+fun TagArray.kinds() = mapNotNull(KindTag::parse)
+
+fun TagArray.description() = firstNotNullOfOrNull(DescriptionTag::parse)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/recommendation/AttestorRecommendationEvent.kt

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.recommendation
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.nip01Core.core.BaseAddressableEvent
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.Kind
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip01Core.tags.dTag.dTag
+import com.vitorpamplona.quartz.nip31Alts.alt
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+@Immutable
+class AttestorRecommendationEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : BaseAddressableEvent(id, pubKey, createdAt, KIND, tags, content, sig) {
+    fun kinds() = tags.kinds()
+
+    fun description() = tags.description()
+
+    companion object {
+        const val KIND = 31873
+        const val ALT_DESCRIPTION = "Attestor Recommendation"
+
+        fun build(
+            attestorPubKey: HexKey,
+            kinds: List<Kind>,
+            description: String? = null,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<AttestorRecommendationEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, "", createdAt) {
+            alt(ALT_DESCRIPTION)
+            dTag(attestorPubKey)
+            kinds(kinds)
+            description?.let { desc(it) }
+            initializer()
+        }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/recommendation/TagArrayBuilderExt.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.recommendation
+
+import com.vitorpamplona.quartz.experimental.attestations.recommendation.tags.DescriptionTag
+import com.vitorpamplona.quartz.experimental.attestations.recommendation.tags.KindTag
+import com.vitorpamplona.quartz.nip01Core.core.Kind
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+
+fun TagArrayBuilder<AttestorRecommendationEvent>.kinds(kinds: List<Kind>) = addAll(KindTag.assemble(kinds))
+
+fun TagArrayBuilder<AttestorRecommendationEvent>.desc(description: String) = addUnique(DescriptionTag.assemble(description))

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/recommendation/TagArrayExt.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.recommendation
+
+import com.vitorpamplona.quartz.experimental.attestations.recommendation.tags.DescriptionTag
+import com.vitorpamplona.quartz.experimental.attestations.recommendation.tags.KindTag
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+
+fun TagArray.kinds() = mapNotNull(KindTag::parse)
+
+fun TagArray.description() = firstNotNullOfOrNull(DescriptionTag::parse)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/recommendation/tags/DescriptionTag.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.recommendation.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+class DescriptionTag {
+    companion object {
+        const val TAG_NAME = "desc"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): String? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+            return tag[1]
+        }
+
+        fun assemble(description: String) = arrayOf(TAG_NAME, description)
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/recommendation/tags/KindTag.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.recommendation.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.Kind
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+class KindTag {
+    companion object {
+        const val TAG_NAME = "k"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): Kind? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+            return tag[1].toIntOrNull()
+        }
+
+        fun assemble(kind: Kind) = arrayOf(TAG_NAME, kind.toString())
+
+        fun assemble(kinds: List<Kind>) = kinds.map { assemble(it) }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/request/AttestationRequestEvent.kt

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.request
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.nip01Core.core.BaseAddressableEvent
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip01Core.tags.dTag.dTag
+import com.vitorpamplona.quartz.nip31Alts.alt
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+@Immutable
+class AttestationRequestEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : BaseAddressableEvent(id, pubKey, createdAt, KIND, tags, content, sig) {
+    fun cashuToken() = tags.cashuToken()
+
+    companion object {
+        const val KIND = 31872
+        const val ALT_DESCRIPTION = "Attestation Request"
+
+        fun build(
+            dTagId: String,
+            content: String = "",
+            attestorPubKeys: List<HexKey> = emptyList(),
+            cashuToken: String? = null,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<AttestationRequestEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, content, createdAt) {
+            alt(ALT_DESCRIPTION)
+            dTag(dTagId)
+            attestorPubKeys(attestorPubKeys)
+            cashuToken?.let { cashuToken(it) }
+            initializer()
+        }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/request/TagArrayBuilderExt.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.request
+
+import com.vitorpamplona.quartz.experimental.attestations.request.tags.CashuTokenTag
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.tags.people.PTag
+
+fun TagArrayBuilder<AttestationRequestEvent>.attestorPubKeys(pubKeys: List<HexKey>) = addAll(pubKeys.map { PTag.assemble(it, null) })
+
+fun TagArrayBuilder<AttestationRequestEvent>.cashuToken(token: String) = addUnique(CashuTokenTag.assemble(token))

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/request/TagArrayExt.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.request
+
+import com.vitorpamplona.quartz.experimental.attestations.request.tags.CashuTokenTag
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+
+fun TagArray.cashuToken() = firstNotNullOfOrNull(CashuTokenTag::parse)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/attestations/request/tags/CashuTokenTag.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.attestations.request.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+class CashuTokenTag {
+    companion object {
+        const val TAG_NAME = "cashu_token"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): String? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+            return tag[1]
+        }
+
+        fun assemble(token: String) = arrayOf(TAG_NAME, token)
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/utils/EventFactory.kt

@@ -20,6 +20,10 @@
  */
 package com.vitorpamplona.quartz.utils
 
+import com.vitorpamplona.quartz.experimental.attestations.attestation.AttestationEvent
+import com.vitorpamplona.quartz.experimental.attestations.proficiency.AttestorProficiencyEvent
+import com.vitorpamplona.quartz.experimental.attestations.recommendation.AttestorRecommendationEvent
+import com.vitorpamplona.quartz.experimental.attestations.request.AttestationRequestEvent
 import com.vitorpamplona.quartz.experimental.audio.header.AudioHeaderEvent
 import com.vitorpamplona.quartz.experimental.audio.track.AudioTrackEvent
 import com.vitorpamplona.quartz.experimental.edits.TextNoteModificationEvent
@@ -185,6 +189,10 @@ class EventFactory {
                 AppDefinitionEvent.KIND -> AppDefinitionEvent(id, pubKey, createdAt, tags, content, sig)
                 AppRecommendationEvent.KIND -> AppRecommendationEvent(id, pubKey, createdAt, tags, content, sig)
                 AppSpecificDataEvent.KIND -> AppSpecificDataEvent(id, pubKey, createdAt, tags, content, sig)
+                AttestationEvent.KIND -> AttestationEvent(id, pubKey, createdAt, tags, content, sig)
+                AttestationRequestEvent.KIND -> AttestationRequestEvent(id, pubKey, createdAt, tags, content, sig)
+                AttestorRecommendationEvent.KIND -> AttestorRecommendationEvent(id, pubKey, createdAt, tags, content, sig)
+                AttestorProficiencyEvent.KIND -> AttestorProficiencyEvent(id, pubKey, createdAt, tags, content, sig)
                 AudioHeaderEvent.KIND -> AudioHeaderEvent(id, pubKey, createdAt, tags, content, sig)
                 AudioTrackEvent.KIND -> AudioTrackEvent(id, pubKey, createdAt, tags, content, sig)
                 BadgeAwardEvent.KIND -> BadgeAwardEvent(id, pubKey, createdAt, tags, content, sig)