- Added `github.com/ebitengine/purego` as a direct dependency to the project. - Removed the unused `p8k.mleku.dev` dependency from the `go.mod` file. - Refactored the `GenerateConversationKeyFromHex` function to clarify parameter order, aligning with the NIP-44 specification. - Enhanced test cases for conversation key generation to ensure proper handling of public key formats and improved error messages. - Updated the `Signer` interface to include methods for extracting and serializing public keys in compressed format.
459 lines
14 KiB
Go
459 lines
14 KiB
Go
// Package secp provides Go bindings to libsecp256k1 without CGO.
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// It uses dynamic library loading via purego to call C functions directly.
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package secp
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import (
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"fmt"
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"runtime"
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"sync"
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"unsafe"
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"github.com/ebitengine/purego"
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)
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// Constants for context flags
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const (
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ContextNone = 1
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ContextVerify = 257 // 1 | (1 << 8)
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ContextSign = 513 // 1 | (1 << 9)
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ContextDeclassify = 1025 // 1 | (1 << 10)
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)
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// EC flags
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const (
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ECCompressed = 258 // SECP256K1_EC_COMPRESSED
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ECUncompressed = 2 // SECP256K1_EC_UNCOMPRESSED
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)
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// Size constants
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const (
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PublicKeySize = 64
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CompressedPublicKeySize = 33
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UncompressedPublicKeySize = 65
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SignatureSize = 64
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CompactSignatureSize = 64
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PrivateKeySize = 32
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SharedSecretSize = 32
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SchnorrSignatureSize = 64
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RecoverableSignatureSize = 65
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)
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var (
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libHandle uintptr
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loadLibOnce sync.Once
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loadLibErr error
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)
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// Function pointers
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var (
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contextCreate func(flags uint32) uintptr
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contextDestroy func(ctx uintptr)
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contextRandomize func(ctx uintptr, seed32 *byte) int32
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ecPubkeyCreate func(ctx uintptr, pubkey *byte, seckey *byte) int32
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ecPubkeySerialize func(ctx uintptr, output *byte, outputlen *uint64, pubkey *byte, flags uint32) int32
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ecPubkeyParse func(ctx uintptr, pubkey *byte, input *byte, inputlen uint64) int32
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ecdsaSign func(ctx uintptr, sig *byte, msg32 *byte, seckey *byte, noncefp uintptr, ndata uintptr) int32
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ecdsaVerify func(ctx uintptr, sig *byte, msg32 *byte, pubkey *byte) int32
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ecdsaSignatureSerializeDer func(ctx uintptr, output *byte, outputlen *uint64, sig *byte) int32
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ecdsaSignatureParseDer func(ctx uintptr, sig *byte, input *byte, inputlen uint64) int32
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ecdsaSignatureSerializeCompact func(ctx uintptr, output64 *byte, sig *byte) int32
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ecdsaSignatureParseCompact func(ctx uintptr, sig *byte, input64 *byte) int32
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ecdsaSignatureNormalize func(ctx uintptr, sigout *byte, sigin *byte) int32
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// Schnorr functions
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schnorrsigSign32 func(ctx uintptr, sig64 *byte, msg32 *byte, keypair *byte, auxrand32 *byte) int32
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schnorrsigVerify func(ctx uintptr, sig64 *byte, msg32 *byte, msglen uint64, pubkey *byte) int32
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keypairCreate func(ctx uintptr, keypair *byte, seckey *byte) int32
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xonlyPubkeyParse func(ctx uintptr, pubkey *byte, input32 *byte) int32
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xonlyPubkeySerialize func(ctx uintptr, output32 *byte, pubkey *byte) int32
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keypairXonlyPub func(ctx uintptr, pubkey *byte, pkParity *int32, keypair *byte) int32
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keypairPub func(ctx uintptr, pubkey *byte, keypair *byte) int32
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// ECDH functions
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ecdh func(ctx uintptr, output *byte, pubkey *byte, seckey *byte, hashfp uintptr, data uintptr) int32
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// Recovery functions
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ecdsaRecoverableSignatureSerializeCompact func(ctx uintptr, output64 *byte, recid *int32, sig *byte) int32
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ecdsaRecoverableSignatureParseCompact func(ctx uintptr, sig *byte, input64 *byte, recid int32) int32
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ecdsaSignRecoverable func(ctx uintptr, sig *byte, msg32 *byte, seckey *byte, noncefp uintptr, ndata uintptr) int32
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ecdsaRecover func(ctx uintptr, pubkey *byte, sig *byte, msg32 *byte) int32
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// Extrakeys
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xonlyPubkeyFromPubkey func(ctx uintptr, xonlyPubkey *byte, pkParity *int32, pubkey *byte) int32
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)
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// LoadLibrary loads the libsecp256k1 shared library
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func LoadLibrary() (err error) {
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loadLibOnce.Do(func() {
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var libPath string
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// Try to find the library
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switch runtime.GOOS {
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case "linux":
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// Try common library paths
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// For linux/amd64, try the bundled library first
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paths := []string{
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"./libsecp256k1.so", // Bundled in repo for linux amd64
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"libsecp256k1.so.5",
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"libsecp256k1.so.2",
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"libsecp256k1.so.1",
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"libsecp256k1.so.0",
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"libsecp256k1.so",
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"/usr/lib/libsecp256k1.so",
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"/usr/local/lib/libsecp256k1.so",
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"/usr/lib/x86_64-linux-gnu/libsecp256k1.so",
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}
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for _, p := range paths {
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libHandle, err = purego.Dlopen(p, purego.RTLD_NOW|purego.RTLD_GLOBAL)
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if err == nil {
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libPath = p
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break
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}
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}
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case "darwin":
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paths := []string{
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"libsecp256k1.2.dylib",
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"libsecp256k1.1.dylib",
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"libsecp256k1.0.dylib",
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"libsecp256k1.dylib",
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"/usr/local/lib/libsecp256k1.dylib",
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"/opt/homebrew/lib/libsecp256k1.dylib",
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}
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for _, p := range paths {
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libHandle, err = purego.Dlopen(p, purego.RTLD_NOW|purego.RTLD_GLOBAL)
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if err == nil {
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libPath = p
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break
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}
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}
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case "windows":
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paths := []string{
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"libsecp256k1-2.dll",
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"libsecp256k1-1.dll",
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"libsecp256k1-0.dll",
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"libsecp256k1.dll",
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"secp256k1.dll",
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}
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for _, p := range paths {
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libHandle, err = purego.Dlopen(p, purego.RTLD_NOW|purego.RTLD_GLOBAL)
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if err == nil {
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libPath = p
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break
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}
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}
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default:
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err = fmt.Errorf("unsupported platform: %s", runtime.GOOS)
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loadLibErr = err
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return
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}
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if err != nil {
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loadLibErr = fmt.Errorf("failed to load libsecp256k1: %w", err)
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return
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}
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// Register symbols
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if err = registerSymbols(); err != nil {
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loadLibErr = fmt.Errorf("failed to register symbols from %s: %w", libPath, err)
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return
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}
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loadLibErr = nil
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})
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return loadLibErr
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}
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// registerSymbols registers all C function symbols
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func registerSymbols() (err error) {
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// Core context functions
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purego.RegisterLibFunc(&contextCreate, libHandle, "secp256k1_context_create")
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purego.RegisterLibFunc(&contextDestroy, libHandle, "secp256k1_context_destroy")
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purego.RegisterLibFunc(&contextRandomize, libHandle, "secp256k1_context_randomize")
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// Public key functions
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purego.RegisterLibFunc(&ecPubkeyCreate, libHandle, "secp256k1_ec_pubkey_create")
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purego.RegisterLibFunc(&ecPubkeySerialize, libHandle, "secp256k1_ec_pubkey_serialize")
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purego.RegisterLibFunc(&ecPubkeyParse, libHandle, "secp256k1_ec_pubkey_parse")
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// ECDSA functions
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purego.RegisterLibFunc(&ecdsaSign, libHandle, "secp256k1_ecdsa_sign")
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purego.RegisterLibFunc(&ecdsaVerify, libHandle, "secp256k1_ecdsa_verify")
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purego.RegisterLibFunc(&ecdsaSignatureSerializeDer, libHandle, "secp256k1_ecdsa_signature_serialize_der")
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purego.RegisterLibFunc(&ecdsaSignatureParseDer, libHandle, "secp256k1_ecdsa_signature_parse_der")
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purego.RegisterLibFunc(&ecdsaSignatureSerializeCompact, libHandle, "secp256k1_ecdsa_signature_serialize_compact")
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purego.RegisterLibFunc(&ecdsaSignatureParseCompact, libHandle, "secp256k1_ecdsa_signature_parse_compact")
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purego.RegisterLibFunc(&ecdsaSignatureNormalize, libHandle, "secp256k1_ecdsa_signature_normalize")
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// Try to load optional modules - don't fail if they're not available
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// Schnorr module
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tryRegister(&schnorrsigSign32, "secp256k1_schnorrsig_sign32")
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tryRegister(&schnorrsigVerify, "secp256k1_schnorrsig_verify")
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tryRegister(&keypairCreate, "secp256k1_keypair_create")
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tryRegister(&xonlyPubkeyParse, "secp256k1_xonly_pubkey_parse")
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tryRegister(&xonlyPubkeySerialize, "secp256k1_xonly_pubkey_serialize")
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tryRegister(&keypairXonlyPub, "secp256k1_keypair_xonly_pub")
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tryRegister(&keypairPub, "secp256k1_keypair_pub")
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tryRegister(&xonlyPubkeyFromPubkey, "secp256k1_xonly_pubkey_from_pubkey")
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// ECDH module
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tryRegister(&ecdh, "secp256k1_ecdh")
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// Recovery module
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tryRegister(&ecdsaRecoverableSignatureSerializeCompact, "secp256k1_ecdsa_recoverable_signature_serialize_compact")
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tryRegister(&ecdsaRecoverableSignatureParseCompact, "secp256k1_ecdsa_recoverable_signature_parse_compact")
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tryRegister(&ecdsaSignRecoverable, "secp256k1_ecdsa_sign_recoverable")
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tryRegister(&ecdsaRecover, "secp256k1_ecdsa_recover")
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return nil
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}
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// tryRegister attempts to register a symbol without failing if it doesn't exist
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func tryRegister(fptr interface{}, symbol string) {
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defer func() {
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if r := recover(); r != nil {
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// Symbol not found, ignore
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}
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}()
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purego.RegisterLibFunc(fptr, libHandle, symbol)
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}
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// Context represents a secp256k1 context
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type Context struct {
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ctx uintptr
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}
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// NewContext creates a new secp256k1 context
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func NewContext(flags uint32) (c *Context, err error) {
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if err = LoadLibrary(); err != nil {
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return
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}
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ctx := contextCreate(flags)
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if ctx == 0 {
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err = fmt.Errorf("failed to create context")
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return
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}
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c = &Context{ctx: ctx}
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runtime.SetFinalizer(c, (*Context).Destroy)
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return
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}
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// Destroy destroys the context
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func (c *Context) Destroy() {
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if c.ctx != 0 {
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contextDestroy(c.ctx)
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c.ctx = 0
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}
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}
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// Randomize randomizes the context with entropy
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func (c *Context) Randomize(seed32 []byte) (err error) {
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if len(seed32) != 32 {
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err = fmt.Errorf("seed must be 32 bytes")
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return
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}
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ret := contextRandomize(c.ctx, &seed32[0])
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if ret != 1 {
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err = fmt.Errorf("failed to randomize context")
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return
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}
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return
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}
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// CreatePublicKey creates a public key from a private key
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func (c *Context) CreatePublicKey(seckey []byte) (pubkey []byte, err error) {
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if len(seckey) != PrivateKeySize {
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err = fmt.Errorf("private key must be %d bytes", PrivateKeySize)
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return
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}
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pubkey = make([]byte, PublicKeySize)
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ret := ecPubkeyCreate(c.ctx, &pubkey[0], &seckey[0])
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if ret != 1 {
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err = fmt.Errorf("failed to create public key")
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return
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}
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return
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}
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// SerializePublicKey serializes a public key
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func (c *Context) SerializePublicKey(pubkey []byte, compressed bool) (output []byte, err error) {
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if len(pubkey) != PublicKeySize {
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err = fmt.Errorf("public key must be %d bytes", PublicKeySize)
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return
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}
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var flags uint32
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if compressed {
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output = make([]byte, CompressedPublicKeySize)
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flags = ECCompressed
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} else {
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output = make([]byte, UncompressedPublicKeySize)
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flags = ECUncompressed
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}
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outputLen := uint64(len(output))
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ret := ecPubkeySerialize(c.ctx, &output[0], &outputLen, &pubkey[0], flags)
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if ret != 1 {
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err = fmt.Errorf("failed to serialize public key")
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return
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}
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output = output[:outputLen]
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return
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}
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// SerializePublicKeyCompressed serializes a public key in compressed format (33 bytes)
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func (c *Context) SerializePublicKeyCompressed(pubkey []byte) (output []byte, err error) {
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return c.SerializePublicKey(pubkey, true)
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}
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// ParsePublicKey parses a serialized public key
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func (c *Context) ParsePublicKey(input []byte) (pubkey []byte, err error) {
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pubkey = make([]byte, PublicKeySize)
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ret := ecPubkeyParse(c.ctx, &pubkey[0], &input[0], uint64(len(input)))
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if ret != 1 {
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err = fmt.Errorf("failed to parse public key")
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return
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}
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return
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}
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// Sign creates an ECDSA signature
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func (c *Context) Sign(msg32 []byte, seckey []byte) (sig []byte, err error) {
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if len(msg32) != 32 {
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err = fmt.Errorf("message must be 32 bytes")
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return
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}
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if len(seckey) != PrivateKeySize {
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err = fmt.Errorf("private key must be %d bytes", PrivateKeySize)
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return
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}
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sig = make([]byte, SignatureSize)
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ret := ecdsaSign(c.ctx, &sig[0], &msg32[0], &seckey[0], 0, 0)
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if ret != 1 {
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err = fmt.Errorf("failed to sign message")
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return
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}
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return
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}
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// Verify verifies an ECDSA signature
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func (c *Context) Verify(msg32 []byte, sig []byte, pubkey []byte) (valid bool, err error) {
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if len(msg32) != 32 {
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err = fmt.Errorf("message must be 32 bytes")
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return
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}
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if len(sig) != SignatureSize {
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err = fmt.Errorf("signature must be %d bytes", SignatureSize)
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return
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}
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if len(pubkey) != PublicKeySize {
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err = fmt.Errorf("public key must be %d bytes", PublicKeySize)
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return
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}
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ret := ecdsaVerify(c.ctx, &sig[0], &msg32[0], &pubkey[0])
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valid = ret == 1
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return
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}
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// SerializeSignatureDER serializes a signature in DER format
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func (c *Context) SerializeSignatureDER(sig []byte) (output []byte, err error) {
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if len(sig) != SignatureSize {
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err = fmt.Errorf("signature must be %d bytes", SignatureSize)
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return
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}
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output = make([]byte, 72) // Max DER signature size
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outputLen := uint64(len(output))
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ret := ecdsaSignatureSerializeDer(c.ctx, &output[0], &outputLen, &sig[0])
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if ret != 1 {
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err = fmt.Errorf("failed to serialize signature")
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return
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}
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output = output[:outputLen]
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return
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}
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// ParseSignatureDER parses a DER-encoded signature
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func (c *Context) ParseSignatureDER(input []byte) (sig []byte, err error) {
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sig = make([]byte, SignatureSize)
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ret := ecdsaSignatureParseDer(c.ctx, &sig[0], &input[0], uint64(len(input)))
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if ret != 1 {
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err = fmt.Errorf("failed to parse DER signature")
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return
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}
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return
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}
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// SerializeSignatureCompact serializes a signature in compact format (64 bytes)
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func (c *Context) SerializeSignatureCompact(sig []byte) (output []byte, err error) {
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if len(sig) != SignatureSize {
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err = fmt.Errorf("signature must be %d bytes", SignatureSize)
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return
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}
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output = make([]byte, CompactSignatureSize)
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ret := ecdsaSignatureSerializeCompact(c.ctx, &output[0], &sig[0])
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if ret != 1 {
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err = fmt.Errorf("failed to serialize signature")
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return
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}
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return
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}
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// ParseSignatureCompact parses a compact (64-byte) signature
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func (c *Context) ParseSignatureCompact(input64 []byte) (sig []byte, err error) {
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if len(input64) != CompactSignatureSize {
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err = fmt.Errorf("compact signature must be %d bytes", CompactSignatureSize)
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return
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}
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sig = make([]byte, SignatureSize)
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ret := ecdsaSignatureParseCompact(c.ctx, &sig[0], &input64[0])
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if ret != 1 {
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err = fmt.Errorf("failed to parse compact signature")
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return
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}
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return
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}
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// NormalizeSignature normalizes a signature to lower-S form
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func (c *Context) NormalizeSignature(sig []byte) (normalized []byte, wasNormalized bool, err error) {
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if len(sig) != SignatureSize {
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err = fmt.Errorf("signature must be %d bytes", SignatureSize)
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return
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}
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normalized = make([]byte, SignatureSize)
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ret := ecdsaSignatureNormalize(c.ctx, &normalized[0], &sig[0])
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wasNormalized = ret == 1
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return
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}
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// Utility function to convert *byte to unsafe.Pointer
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func bytesToPtr(b []byte) unsafe.Pointer {
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if len(b) == 0 {
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return nil
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}
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return unsafe.Pointer(&b[0])
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}
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