1 files changed, 50 insertions, 1 deletions
diff --git a/crypto/secp256k1/secp256.go b/crypto/secp256k1/secp256.go
index 0ffa04fe0..eefbb99ee 100644
--- a/crypto/secp256k1/secp256.go
+++ b/crypto/secp256k1/secp256.go
@@ -38,6 +38,7 @@ import "C"
 
 import (
 	"errors"
+	"math/big"
 	"unsafe"
 )
 
@@ -55,6 +56,7 @@ var (
 	ErrInvalidSignatureLen = errors.New("invalid signature length")
 	ErrInvalidRecoveryID   = errors.New("invalid signature recovery id")
 	ErrInvalidKey          = errors.New("invalid private key")
+	ErrInvalidPubkey       = errors.New("invalid public key")
 	ErrSignFailed          = errors.New("signing failed")
 	ErrRecoverFailed       = errors.New("recovery failed")
 )
@@ -113,12 +115,59 @@ func RecoverPubkey(msg []byte, sig []byte) ([]byte, error) {
 		sigdata = (*C.uchar)(unsafe.Pointer(&sig[0]))
 		msgdata = (*C.uchar)(unsafe.Pointer(&msg[0]))
 	)
-	if C.secp256k1_ecdsa_recover_pubkey(context, (*C.uchar)(unsafe.Pointer(&pubkey[0])), sigdata, msgdata) == 0 {
+	if C.secp256k1_ext_ecdsa_recover(context, (*C.uchar)(unsafe.Pointer(&pubkey[0])), sigdata, msgdata) == 0 {
 		return nil, ErrRecoverFailed
 	}
 	return pubkey, nil
 }
 
+// VerifySignature checks that the given pubkey created signature over message.
+// The signature should be in [R || S] format.
+func VerifySignature(pubkey, msg, signature []byte) bool {
+	if len(msg) != 32 || len(signature) != 64 || len(pubkey) == 0 {
+		return false
+	}
+	sigdata := (*C.uchar)(unsafe.Pointer(&signature[0]))
+	msgdata := (*C.uchar)(unsafe.Pointer(&msg[0]))
+	keydata := (*C.uchar)(unsafe.Pointer(&pubkey[0]))
+	return C.secp256k1_ext_ecdsa_verify(context, sigdata, msgdata, keydata, C.size_t(len(pubkey))) != 0
+}
+
+// DecompressPubkey parses a public key in the 33-byte compressed format.
+// It returns non-nil coordinates if the public key is valid.
+func DecompressPubkey(pubkey []byte) (x, y *big.Int) {
+	if len(pubkey) != 33 {
+		return nil, nil
+	}
+	var (
+		pubkeydata = (*C.uchar)(unsafe.Pointer(&pubkey[0]))
+		pubkeylen  = C.size_t(len(pubkey))
+		out        = make([]byte, 65)
+		outdata    = (*C.uchar)(unsafe.Pointer(&out[0]))
+		outlen     = C.size_t(len(out))
+	)
+	if C.secp256k1_ext_reencode_pubkey(context, outdata, outlen, pubkeydata, pubkeylen) == 0 {
+		return nil, nil
+	}
+	return new(big.Int).SetBytes(out[1:33]), new(big.Int).SetBytes(out[33:])
+}
+
+// CompressPubkey encodes a public key to 33-byte compressed format.
+func CompressPubkey(x, y *big.Int) []byte {
+	var (
+		pubkey     = S256().Marshal(x, y)
+		pubkeydata = (*C.uchar)(unsafe.Pointer(&pubkey[0]))
+		pubkeylen  = C.size_t(len(pubkey))
+		out        = make([]byte, 33)
+		outdata    = (*C.uchar)(unsafe.Pointer(&out[0]))
+		outlen     = C.size_t(len(out))
+	)
+	if C.secp256k1_ext_reencode_pubkey(context, outdata, outlen, pubkeydata, pubkeylen) == 0 {
+		panic("libsecp256k1 error")
+	}
+	return out
+}
+
 func checkSignature(sig []byte) error {
 	if len(sig) != 65 {
 		return ErrInvalidSignatureLen