84 lines
2.6 KiB
Go
84 lines
2.6 KiB
Go
//go:build libsecp256k1
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package nostr
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/*
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#cgo CFLAGS: -I${SRCDIR}/libsecp256k1/include -I${SRCDIR}/libsecp256k1/src
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#cgo CFLAGS: -DECMULT_GEN_PREC_BITS=4
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#cgo CFLAGS: -DECMULT_WINDOW_SIZE=15
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#cgo CFLAGS: -DENABLE_MODULE_SCHNORRSIG=1
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#cgo CFLAGS: -DENABLE_MODULE_EXTRAKEYS=1
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#include "./libsecp256k1/src/secp256k1.c"
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#include "./libsecp256k1/src/precomputed_ecmult.c"
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#include "./libsecp256k1/src/precomputed_ecmult_gen.c"
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#include "./libsecp256k1/src/ecmult_gen.h"
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#include "./libsecp256k1/src/ecmult.h"
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#include "./libsecp256k1/src/modules/extrakeys/main_impl.h"
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#include "./libsecp256k1/src/modules/schnorrsig/main_impl.h"
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#include "./libsecp256k1/include/secp256k1.h"
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#include "./libsecp256k1/include/secp256k1_extrakeys.h"
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#include "./libsecp256k1/include/secp256k1_schnorrsig.h"
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*/
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import "C"
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import (
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"crypto/rand"
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"crypto/sha256"
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"errors"
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"fmt"
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"unsafe"
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"github.com/btcsuite/btcd/btcec/v2/schnorr"
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)
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func (evt Event) CheckSignature() (bool, error) {
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msg := sha256.Sum256(evt.Serialize())
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var xonly C.secp256k1_xonly_pubkey
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if C.secp256k1_xonly_pubkey_parse(globalSecp256k1Context, &xonly, (*C.uchar)(unsafe.Pointer(&evt.PubKey[0]))) != 1 {
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return false, fmt.Errorf("failed to parse xonly pubkey")
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}
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res := C.secp256k1_schnorrsig_verify(globalSecp256k1Context, (*C.uchar)(unsafe.Pointer(&evt.Sig[0])), (*C.uchar)(unsafe.Pointer(&msg[0])), 32, &xonly)
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return res == 1, nil
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}
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// Sign signs an event with a given privateKey.
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func (evt *Event) Sign(secretKey [32]byte, signOpts ...schnorr.SignOption) error {
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if evt.Tags == nil {
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evt.Tags = make(Tags, 0)
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}
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var keypair C.secp256k1_keypair
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if C.secp256k1_keypair_create(globalSecp256k1Context, &keypair, (*C.uchar)(unsafe.Pointer(&secretKey[0]))) != 1 {
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return errors.New("failed to parse private key")
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}
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var xonly C.secp256k1_xonly_pubkey
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C.secp256k1_keypair_xonly_pub(globalSecp256k1Context, &xonly, nil, &keypair)
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C.secp256k1_xonly_pubkey_serialize(globalSecp256k1Context, (*C.uchar)(unsafe.Pointer(&evt.PubKey[0])), &xonly)
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h := sha256.Sum256(evt.Serialize())
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var random [32]byte
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rand.Read(random[:])
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if C.secp256k1_schnorrsig_sign32(globalSecp256k1Context, (*C.uchar)(unsafe.Pointer(&evt.Sig[0])), (*C.uchar)(unsafe.Pointer(&h[0])), &keypair, (*C.uchar)(unsafe.Pointer(&random[0]))) != 1 {
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return errors.New("failed to sign message")
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}
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evt.ID = h
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return nil
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}
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var globalSecp256k1Context *C.secp256k1_context
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func init() {
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globalSecp256k1Context = C.secp256k1_context_create(C.SECP256K1_CONTEXT_SIGN | C.SECP256K1_CONTEXT_VERIFY)
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if globalSecp256k1Context == nil {
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panic("failed to create secp256k1 context")
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}
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}
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