BIP-340 public keys always have even y, so the y-parity prefix byte
(0x02) is redundant when the caller already has the 32-byte x-only
pubkey. This new overload takes the x-only pubkey directly, avoiding:
1. The expensive G multiplication to derive the pubkey (~20μs on Android)
2. The 33→32 byte array copy that signSchnorrWithPubKey does internally
Added to:
- Secp256k1.signSchnorrWithXOnlyPubKey (core implementation)
- Secp256k1Instance (expect/actual, falls back to C lib's signSchnorr
since the native C lib always derives pubkey internally)
- Secp256k1InstanceOurs (uses the optimized pure-Kotlin path)
- Nip01Crypto.signWithPubKey (app-level convenience)
The app's KeyPair already stores the 32-byte x-only pubkey. Callers
like EventAssembler.hashAndSign can pass it through to skip the
G multiplication entirely.
https://claude.ai/code/session_01EMY5RnXb9rnsyU2KbXrSaY
Document WHY each approach was chosen, what alternatives were tested,
and what the measured impact was — so future contributors don't
accidentally revert optimizations or repeat failed experiments.
Key decisions documented:
- uLt() expect/actual: why XOR on Android, Long.compareUnsigned on JVM,
and why a shared inline fun in commonMain caused 30% JVM regression
- fieldMulReduceWith: why fused mul+reduce, why inline+crossinline,
why NOT 5x52 limbs, why NOT single-method with all API branches
- @JvmField: why it's required on MutablePoint/AffinePoint/PointScratch,
with bytecode counts showing ~7,450 + ~2,000 virtual getter calls
eliminated per verify
https://claude.ai/code/session_01EMY5RnXb9rnsyU2KbXrSaY
The previous approach inlined all 3 API-level branches into a single
fieldMulReduce method (~600 DEX instructions). ART's register allocator
produces suboptimal code for such large methods, causing stack spills
that negate the benefit of eliminating wrapper calls.
Split each API-level path into its own private function (~200 DEX
instructions each). ART JIT-compiles only the hot one (fieldMulApi35
on API 35+) with full optimization, while the tiny dispatch function
(fieldMulReduce) is easily devirtualized and inlined.
https://claude.ai/code/session_01EMY5RnXb9rnsyU2KbXrSaY
On Android (ART), the unsignedMultiplyHigh wrapper function has per-call
branching for API level detection that prevents ART's JIT from inlining
the intrinsic into the hot loop. This creates ~10,000 extra function
calls per signature verify (20 wrapper calls × 500 field muls).
This commit introduces fieldMulReduce/fieldSqrReduce as expect/actual
functions that fuse U256.mulWide + FieldP.reduceWide into a single
compilation unit. The multiply-high intrinsic is passed as a crossinline
lambda and inlined at each call site, producing platform-specific code
with zero wrapper overhead:
- Android API 35+: Math.unsignedMultiplyHigh inlined directly (UMULH)
- Android API 31-34: Math.multiplyHigh + correction inlined (SMULH)
- Android API <31: pure-Kotlin fallback inlined
- JVM: Math.unsignedMultiplyHigh inlined directly
- Native: pure-Kotlin fallback inlined
The API level check happens ONCE per fieldMulReduce call (outermost
branch) rather than per multiply-high call (innermost loop), so ART
profiles and JIT-compiles only the hot path.
https://claude.ai/code/session_01EMY5RnXb9rnsyU2KbXrSaY
ThreadLocal.withInitial is a JVM-only API that doesn't compile on
Kotlin/Native or iOS targets. Replace all usages in commonMain
(FieldP.kt, Point.kt) with a new ScratchLocal expect/actual:
- jvmMain/androidMain: delegates to java.lang.ThreadLocal (same behavior)
- nativeMain: holds value directly (Kotlin/Native coroutines are
cooperative, scratch buffers don't need thread isolation)
https://claude.ai/code/session_01BhU63WUe9AhikZxRdw3Lpg
Three Android-specific optimizations:
1. Use Math.unsignedMultiplyHigh on API 35+ (Android 15): single UMULH
instruction, eliminates the 4-insn signed→unsigned correction that
the fallback path requires. Same optimization as our JVM 18+ path.
2. Use Math.multiplyHigh + correction on API 31-34 (Android 12-14):
avoids the pure-Kotlin 4×32-bit sub-product fallback entirely.
3. Resolve API level check ONCE at class load via static final fields
(HAS_MULTIPLY_HIGH, HAS_UNSIGNED_MULTIPLY_HIGH) instead of checking
Build.VERSION.SDK_INT on every call. These functions are called 16×
per field multiply (~12,000× per signature verify), so eliminating
the per-call branch matters.
Performance tiers on Android:
API 35+ (Android 15): ~same as JVM 18+ (UMULH intrinsic)
API 31-34 (Android 12-14): SMULH + 3 correction insns per product
API 26-30 (Android 8-11): pure-Kotlin fallback (4 sub-products)
https://claude.ai/code/session_01BhU63WUe9AhikZxRdw3Lpg
Foundation layer for the 4×64-bit limb optimization. This commit rewrites
U256 from IntArray(8) to LongArray(4) and adds platform-specific
Math.multiplyHigh for 64×64→128-bit products:
- JVM: Math.multiplyHigh intrinsic (single IMULH/SMULH instruction)
- Android API 31+: Math.multiplyHigh, fallback to pure Kotlin on older
- Native: pure Kotlin fallback (4 sub-products per multiplyHigh call)
The 4×64 representation reduces inner products from 64 to 16 per field
multiply on JVM, a potential ~1.5-2× speedup on the critical path.
NOTE: This commit intentionally breaks the build — FieldP, ScalarN, Glv,
Point, KeyCodec, Secp256k1, and all tests still expect IntArray(8).
They will be updated in subsequent commits.
https://claude.ai/code/session_01BhU63WUe9AhikZxRdw3Lpg
Implements all secp256k1 operations used by Secp256k1Instance in pure Kotlin,
eliminating the dependency on native secp256k1 bindings (fr.acinq.secp256k1-kmp).
Implementation:
- Field.kt: 256-bit unsigned integer arithmetic, field mod p, scalar mod n
- Point.kt: EC point operations (Jacobian coords), point parsing/serialization
- Secp256k1.kt: Public API - pubkeyCreate, pubKeyCompress, secKeyVerify,
signSchnorr/verifySchnorr (BIP-340), privKeyTweakAdd, pubKeyTweakMul
Tests (36 total):
- All 19 BIP-340 test vectors (signing vectors 0-3, 15-18; verify vectors 4-14)
- ACINQ test vectors for key creation, compression, secKeyVerify, privKeyTweakAdd,
pubKeyTweakMul
- ECDH symmetry and sign/verify round-trip tests
Secp256k1Instance is now a concrete object in commonMain instead of expect/actual,
delegating to the pure-Kotlin implementation. All existing NIP-44 and BIP-32 tests
pass with the new implementation.
https://claude.ai/code/session_01BhU63WUe9AhikZxRdw3Lpg
Before (4 steps, manual wiring):
val transport = AndroidBleTransport(context)
val mesh = BleMeshManager(transport, object : BleMeshListener { ... })
transport.setListener(mesh)
mesh.start()
After (2 steps, auto-wired):
val mesh = BleNostrMesh(AndroidBleTransport(context))
mesh.onEvent { event, peer -> saveEvent(event) }
mesh.start()
The facade uses lambda callbacks instead of interface implementation,
and auto-wires the transport listener via AndroidBleTransportContract.
BleMeshManager remains available for advanced use cases.
https://claude.ai/code/session_01Tz5E73Rj7tL48A3qUGS5DT
Reviewed the samiz BLE implementation and fixed compatibility issues:
- Chunk index: changed from 2 bytes to 1 byte (matching samiz/NIP-BE example)
- Chunk overhead: 2 bytes total (1 index + 1 total count), not 3
- chunkSize parameter now means payload size (500), not total chunk size
- Android: TX power HIGH, advertise timeout indefinite (matching samiz)
- Android: request MTU 512 and CONNECTION_PRIORITY_HIGH on connect
- Android: discover services after MTU negotiation (samiz flow)
- Android: set WRITE_TYPE_DEFAULT on write characteristic
- MTU-to-chunkSize: properly accounts for ATT overhead (3) + chunk overhead (2)
These changes ensure wire-level compatibility with samiz devices.
https://claude.ai/code/session_01Tz5E73Rj7tL48A3qUGS5DT
Adds full NIP-BE implementation for BLE-based Nostr peer-to-peer
messaging and synchronization with KMP support across all targets.
Protocol layer (commonMain):
- BleConfig: NIP-BE constants (service UUID, characteristic UUIDs)
- BleMessageChunker: DEFLATE compression + chunk splitting/joining
- BleRole/assignRole: Role assignment based on UUID comparison
- BleTransport: Platform-agnostic BLE transport interface
- BleNostrClient: IRelayClient implementation over BLE
- BleNostrServer: Relay server over BLE with notification support
- BleMeshManager: High-level mesh manager with auto-discovery,
role assignment, and event broadcasting
- BleChunkAssembler: Thread-safe chunk reassembly
Platform support:
- Deflate expect/actual for jvmAndroid, apple, and linux targets
- AndroidBleTransport: Full Android BLE implementation using GATT
server/client APIs with scanning, advertising, and MTU negotiation
Tests: Deflate compression, message chunking, role assignment,
and chunk assembly (25 tests passing).
https://claude.ai/code/session_01Tz5E73Rj7tL48A3qUGS5DT
- Add optional throwable parameter to d() and i() across all platforms
- Add inline lambda overloads for all log levels to defer message
construction, avoiding string allocation when level is filtered
- Restore VoiceMessagePreview to pass throwable directly
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Deprecated APIs in Quartz are kept for library consumers but internal usages
now carry @Suppress annotations so the module builds warning-free. Also
replaces redundant .toInt() on hex Int literals in ChaCha20Core and migrates
deprecated java.net.URL to URI.resolve() in ServerInfoParser.
The spotless license header delimiter is updated to recognize @file: annotations.
https://claude.ai/code/session_01EwS56YAGGnnac5EuwhaUSs
Claude
Vitor Pamplona
greenart7c3
davotoulaandClaude Opus 4.6
nrobi144