Add a complete C implementation of secp256k1 elliptic curve operations
alongside the existing Kotlin implementation, enabling direct comparison
and extraction of maximum performance from each platform (ARM64, x86_64).
C Implementation (quartz/src/main/c/secp256k1/):
- field.h/c: 5x52-bit limb field arithmetic with __int128 support and
lazy reduction (12-bit headroom per limb vs Kotlin's fully-packed 4x64)
- scalar.h/c: Scalar mod n arithmetic, GLV decomposition, wNAF encoding
- point.h/c: Jacobian point operations (3M+4S double, 8M+3S mixed add),
GLV+wNAF scalar multiplication, Strauss/Shamir dual scalar multiply,
Montgomery batch-to-affine, precomputed G tables (wNAF-12)
- schnorr.c: BIP-340 Schnorr sign/verify/verifyFast/verifyBatch with
pubkey decompression cache and precomputed tag hash prefixes
- sha256.c: Self-contained SHA-256 for BIP-340 tagged hashes
- secp256k1_c.h: Public API matching the Kotlin Secp256k1 object
- jni_bridge.c: JNI bridge for JVM/Android integration
- benchmark.c: Standalone C benchmark (cmake build)
- CMakeLists.txt: Build system with ARM64/x86_64 optimization flags
Kotlin Integration:
- Secp256k1InstanceC: expect/actual wrapper (commonMain/jvmMain/androidMain/nativeMain)
- Secp256k1C: JVM JNI binding class
- Secp256k1TripleBenchmark: Three-way JVM benchmark (ACINQ vs Kotlin vs Custom C)
- Secp256k1CBenchmark: Android benchmark for the C implementation
Current status: sign works correctly (verified against BIP-340 test vectors),
verify path needs ecmult_double_g debugging (GLV wNAF-12 table issue). The
comb table for ecmult_gen also needs fixing (currently falls back to GLV+wNAF).
Field arithmetic is fully verified: 5x52 limbs with R=0x1000003D10 fold.
https://claude.ai/code/session_011KVZhDcV2G7idNWEBz12GY
Add verifySchnorrBatch to Secp256k1InstanceOurs wrapper and add
Android benchmark tests for batch(8) and batch(16).
To get per-event cost: ns/op ÷ batchSize.
JVM benchmark showed 4-7× speedup over individual verify.
Android results TBD.
https://claude.ai/code/session_01EMY5RnXb9rnsyU2KbXrSaY
Wire verifySchnorrFast (x-check only, no y-parity inversion) into:
- Secp256k1InstanceOurs wrapper for app-level usage
- Android benchmark as verifySchnorrFastOurs for Pixel 8 measurement
Expected: ~15% faster than verifySchnorrOurs (~100μs vs ~120μs on Pixel 8)
https://claude.ai/code/session_01EMY5RnXb9rnsyU2KbXrSaY
Creates Secp256k1Benchmark.kt in the benchmark module using AndroidX
Benchmark (Jetpack Microbenchmark) to measure all secp256k1 operations
on real Android hardware/emulator with proper warmup and statistics.
Benchmarks: verifySchnorr, signSchnorr, compressedPubKeyFor,
secKeyVerify, pubKeyCompress, privateKeyAdd, pubKeyTweakMulCompact.
Run with: ./gradlew :benchmark:connectedAndroidTest
The existing SignVerifyBenchmark already tests sign/verify through
Nip01Crypto, but this new benchmark tests the Secp256k1Instance
operations directly, matching the JVM benchmark for comparison.
https://claude.ai/code/session_01BhU63WUe9AhikZxRdw3Lpg
- Fully converts OpenTimestamp Java codebase to Kotlin, migrating the sync and async HTTP call interfaces to OkHttp and coroutines
- Redesigns parsing of relay commands, messages and filters for performance in Jackson.
- Starts the use of KotlinX Serialization when speed is not a requirement
- Migrates all Jackson field annotations to Kotlin Serialization
- Migrates Regex use in Quarts to Kotlin's Regex class
- Migrates Base64 from Android to Kotlin
- Migrates UUID from Android/Java to Kotlin
- Migrates LRUCache usage from Android/Java to Kotlin collections
- Migrates all String to bytearray conversions to Kotlin methods
- Migrates all System.arraycopy calls to kotlin native ones.
- Separates parsing code from the data classes Companion objects
- Exposes Rfc3986 normalizations to each platform.
- Exposes URI parsing classes to each platform.
- Exposes URL Encoders to each platform.
- Exposes BigDecimal to each platform.
- Exposes the Url Detector to each platform.
- Exposes MacInstances to each platform
- Exposes Diggest instances to each platform.
- Exposes a BitSet to each platform.
- Exposes GZip to each platform.
- Exposes Secp256k1 to each platform.
- Exposes SecureRandom to each platform.
- Exposes Time in seconds to each platform.
- Exposes the LargeCache to each platform.
- Exposes AES CBC and AES GCM encryption/decryption to each platform
- Migrate test assertions to Kotlin Tests
- Exposes Address class to each platform because of the Parceleable
- Creates our own ByteArrayOutputStream.
- Removes Lock features inside the Bloomfilters because we don't need data consistency/
- Migrates UserMetadata parser from Jackson to Kotlin serialization
- Removes the need for Static methods in each tag.
- Adds an event template serializer
- Adds KotlinX Datetime to migrate some of the date-based logs
- Adds support for LibSodium in the JVM platform
- Creates a shared test build for iOS targets
- Fixes several usages of Reflection when serializing classes
- Fixes a bug on loading RelayDB for the HintBloom filter test
- Increases the Bloom filter space to better use hints in the app.
- Removes support for iOS in x86
- Creates a Jackson mapper just for NIP-55, which stays in the Android build only.
- Keeps the event store in the android build as well.
- Removes @Syncronized tags in favor of Mutexes.
- Improved sendAndWaitForResponse NostrClient method to properly account for returns from each relay.
- Removes the need for GlobalScope and async calls in the downloadFirstEvent method.
- Restructures the parser and serialization of the relay messages and commands for performance with Jackson
- Removes the dependency on Jackson's error classes across the codebase.
- Moves the hint to quote tag extension methods to their own packages.
- Speeds up the generation of Bech32 addresses
- Migrates NIP-6 and Blossom uploads to use Kotlin Serialization
Claude