diff options
| -rw-r--r-- | crypto/secp256k1/secp256.go | 112 | ||||
| -rw-r--r-- | crypto/secp256k1/secp256_test.go | 15 |
2 files changed, 48 insertions, 79 deletions
diff --git a/crypto/secp256k1/secp256.go b/crypto/secp256k1/secp256.go index a2104016a..634e1c0b8 100644 --- a/crypto/secp256k1/secp256.go +++ b/crypto/secp256k1/secp256.go @@ -39,7 +39,6 @@ package secp256k1 import "C" import ( - "bytes" "errors" "unsafe" @@ -64,6 +63,12 @@ func init() { context = C.secp256k1_context_create(3) // SECP256K1_START_SIGN | SECP256K1_START_VERIFY } +var ( + ErrInvalidMsgLen = errors.New("invalid message length for signature recovery") + ErrInvalidSignatureLen = errors.New("invalid signature length") + ErrInvalidRecoveryID = errors.New("invalid signature recovery id") +) + func GenerateKeyPair() ([]byte, []byte) { var seckey []byte = randentropy.GetEntropyCSPRNG(32) var seckey_ptr *C.uchar = (*C.uchar)(unsafe.Pointer(&seckey[0])) @@ -177,69 +182,20 @@ func VerifySeckeyValidity(seckey []byte) error { return nil } -func VerifySignatureValidity(sig []byte) bool { - //64+1 - if len(sig) != 65 { - return false - } - //malleability check, highest bit must be 1 - if (sig[32] & 0x80) == 0x80 { - return false - } - //recovery id check - if sig[64] >= 4 { - return false - } - - return true -} - -//for compressed signatures, does not need pubkey -func VerifySignature(msg []byte, sig []byte, pubkey1 []byte) error { - if msg == nil || sig == nil || pubkey1 == nil { - return errors.New("inputs must be non-nil") - } - if len(sig) != 65 { - return errors.New("invalid signature length") - } - if len(pubkey1) != 65 { - return errors.New("Invalid public key length") - } - - //to enforce malleability, highest bit of S must be 0 - //S starts at 32nd byte - if (sig[32] & 0x80) == 0x80 { //highest bit must be 1 - return errors.New("Signature not malleable") - } - - if sig[64] >= 4 { - return errors.New("Recover byte invalid") - } - - // if pubkey recovered, signature valid - pubkey2, err := RecoverPubkey(msg, sig) - if err != nil { - return err - } - if len(pubkey2) != 65 { - return errors.New("Invalid recovered public key length") - } - if !bytes.Equal(pubkey1, pubkey2) { - return errors.New("Public key does not match recovered public key") - } - - return nil -} - -// recovers a public key from the signature +// RecoverPubkey returns the the public key of the signer. +// msg must be the 32-byte hash of the message to be signed. +// sig must be a 65-byte compact ECDSA signature containing the +// recovery id as the last element. func RecoverPubkey(msg []byte, sig []byte) ([]byte, error) { - if len(sig) != 65 { - return nil, errors.New("Invalid signature length") + if len(msg) != 32 { + return nil, ErrInvalidMsgLen + } + if err := checkSignature(sig); err != nil { + return nil, err } msg_ptr := (*C.uchar)(unsafe.Pointer(&msg[0])) sig_ptr := (*C.uchar)(unsafe.Pointer(&sig[0])) - pubkey := make([]byte, 64) /* this slice is used for both the recoverable signature and the @@ -248,17 +204,15 @@ func RecoverPubkey(msg []byte, sig []byte) ([]byte, error) { pubkey recovery is one bottleneck during load in Ethereum */ bytes65 := make([]byte, 65) - pubkey_ptr := (*C.secp256k1_pubkey)(unsafe.Pointer(&pubkey[0])) recoverable_sig_ptr := (*C.secp256k1_ecdsa_recoverable_signature)(unsafe.Pointer(&bytes65[0])) - recid := C.int(sig[64]) + ret := C.secp256k1_ecdsa_recoverable_signature_parse_compact( context, recoverable_sig_ptr, sig_ptr, recid) - if ret == C.int(0) { return nil, errors.New("Failed to parse signature") } @@ -269,20 +223,28 @@ func RecoverPubkey(msg []byte, sig []byte) ([]byte, error) { recoverable_sig_ptr, msg_ptr, ) - if ret == C.int(0) { return nil, errors.New("Failed to recover public key") - } else { - serialized_pubkey_ptr := (*C.uchar)(unsafe.Pointer(&bytes65[0])) - - var output_len C.size_t - C.secp256k1_ec_pubkey_serialize( // always returns 1 - context, - serialized_pubkey_ptr, - &output_len, - pubkey_ptr, - 0, // SECP256K1_EC_COMPRESSED - ) - return bytes65, nil } + + serialized_pubkey_ptr := (*C.uchar)(unsafe.Pointer(&bytes65[0])) + var output_len C.size_t + C.secp256k1_ec_pubkey_serialize( // always returns 1 + context, + serialized_pubkey_ptr, + &output_len, + pubkey_ptr, + 0, // SECP256K1_EC_COMPRESSED + ) + return bytes65, nil +} + +func checkSignature(sig []byte) error { + if len(sig) != 65 { + return ErrInvalidSignatureLen + } + if sig[64] >= 4 { + return ErrInvalidRecoveryID + } + return nil } diff --git a/crypto/secp256k1/secp256_test.go b/crypto/secp256k1/secp256_test.go index 45c448f3c..cb71ea5e7 100644 --- a/crypto/secp256k1/secp256_test.go +++ b/crypto/secp256k1/secp256_test.go @@ -56,6 +56,17 @@ func TestSignatureValidity(t *testing.T) { } } +func TestInvalidRecoveryID(t *testing.T) { + _, seckey := GenerateKeyPair() + msg := randentropy.GetEntropyCSPRNG(32) + sig, _ := Sign(msg, seckey) + sig[64] = 99 + _, err := RecoverPubkey(msg, sig) + if err != ErrInvalidRecoveryID { + t.Fatalf("got %q, want %q", err, ErrInvalidRecoveryID) + } +} + func TestSignAndRecover(t *testing.T) { pubkey1, seckey := GenerateKeyPair() msg := randentropy.GetEntropyCSPRNG(32) @@ -70,10 +81,6 @@ func TestSignAndRecover(t *testing.T) { if !bytes.Equal(pubkey1, pubkey2) { t.Errorf("pubkey mismatch: want: %x have: %x", pubkey1, pubkey2) } - err = VerifySignature(msg, sig, pubkey1) - if err != nil { - t.Errorf("signature verification error: %s", err) - } } func TestRandomMessagesWithSameKey(t *testing.T) { |