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authorFelix Lange <fjl@users.noreply.github.com>2017-12-06 23:07:08 +0800
committerGitHub <noreply@github.com>2017-12-06 23:07:08 +0800
commite85b68ef53e80eb66c7ab394c57e9eb146a60b91 (patch)
tree92a728f14c9a0d42b50f2410d3c67a46795364d6 /crypto
parent6e613cf3de6ebfd14edd5a332baf6e4079c1c86f (diff)
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crypto: add DecompressPubkey, VerifySignature (#15615)
We need those operations for p2p/enr. Also upgrade github.com/btcsuite/btcd/btcec to the latest version and improve BenchmarkSha3. The benchmark printed extra output that confused tools like benchstat and ignored N.
Diffstat (limited to 'crypto')
-rw-r--r--crypto/crypto_test.go8
-rw-r--r--crypto/secp256k1/ext.h49
-rw-r--r--crypto/secp256k1/secp256.go29
-rw-r--r--crypto/signature_cgo.go18
-rw-r--r--crypto/signature_nocgo.go31
-rw-r--r--crypto/signature_test.go92
6 files changed, 212 insertions, 15 deletions
diff --git a/crypto/crypto_test.go b/crypto/crypto_test.go
index 92302948e..b4c441e5f 100644
--- a/crypto/crypto_test.go
+++ b/crypto/crypto_test.go
@@ -20,12 +20,10 @@ import (
"bytes"
"crypto/ecdsa"
"encoding/hex"
- "fmt"
"io/ioutil"
"math/big"
"os"
"testing"
- "time"
"github.com/ethereum/go-ethereum/common"
)
@@ -44,13 +42,9 @@ func TestKeccak256Hash(t *testing.T) {
func BenchmarkSha3(b *testing.B) {
a := []byte("hello world")
- amount := 1000000
- start := time.Now()
- for i := 0; i < amount; i++ {
+ for i := 0; i < b.N; i++ {
Keccak256(a)
}
-
- fmt.Println(amount, ":", time.Since(start))
}
func TestSign(t *testing.T) {
diff --git a/crypto/secp256k1/ext.h b/crypto/secp256k1/ext.h
index ee759fde6..b0f30b73c 100644
--- a/crypto/secp256k1/ext.h
+++ b/crypto/secp256k1/ext.h
@@ -46,6 +46,55 @@ static int secp256k1_ecdsa_recover_pubkey(
return secp256k1_ec_pubkey_serialize(ctx, pubkey_out, &outputlen, &pubkey, SECP256K1_EC_UNCOMPRESSED);
}
+// secp256k1_ecdsa_verify_enc verifies an encoded compact signature.
+//
+// Returns: 1: signature is valid
+// 0: signature is invalid
+// Args: ctx: pointer to a context object (cannot be NULL)
+// In: sigdata: pointer to a 64-byte signature (cannot be NULL)
+// msgdata: pointer to a 32-byte message (cannot be NULL)
+// pubkeydata: pointer to public key data (cannot be NULL)
+// pubkeylen: length of pubkeydata
+static int secp256k1_ecdsa_verify_enc(
+ const secp256k1_context* ctx,
+ const unsigned char *sigdata,
+ const unsigned char *msgdata,
+ const unsigned char *pubkeydata,
+ size_t pubkeylen
+) {
+ secp256k1_ecdsa_signature sig;
+ secp256k1_pubkey pubkey;
+
+ if (!secp256k1_ecdsa_signature_parse_compact(ctx, &sig, sigdata)) {
+ return 0;
+ }
+ if (!secp256k1_ec_pubkey_parse(ctx, &pubkey, pubkeydata, pubkeylen)) {
+ return 0;
+ }
+ return secp256k1_ecdsa_verify(ctx, &sig, msgdata, &pubkey);
+}
+
+// secp256k1_decompress_pubkey decompresses a public key.
+//
+// Returns: 1: public key is valid
+// 0: public key is invalid
+// Args: ctx: pointer to a context object (cannot be NULL)
+// Out: pubkey_out: the serialized 65-byte public key (cannot be NULL)
+// In: pubkeydata: pointer to 33 bytes of compressed public key data (cannot be NULL)
+static int secp256k1_decompress_pubkey(
+ const secp256k1_context* ctx,
+ unsigned char *pubkey_out,
+ const unsigned char *pubkeydata
+) {
+ secp256k1_pubkey pubkey;
+
+ if (!secp256k1_ec_pubkey_parse(ctx, &pubkey, pubkeydata, 33)) {
+ return 0;
+ }
+ size_t outputlen = 65;
+ return secp256k1_ec_pubkey_serialize(ctx, pubkey_out, &outputlen, &pubkey, SECP256K1_EC_UNCOMPRESSED);
+}
+
// secp256k1_pubkey_scalar_mul multiplies a point by a scalar in constant time.
//
// Returns: 1: multiplication was successful
diff --git a/crypto/secp256k1/secp256.go b/crypto/secp256k1/secp256.go
index 0ffa04fe0..00a1f8aaa 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")
)
@@ -119,6 +121,33 @@ func RecoverPubkey(msg []byte, sig []byte) ([]byte, error) {
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_ecdsa_verify_enc(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
+ }
+ buf := make([]byte, 65)
+ bufdata := (*C.uchar)(unsafe.Pointer(&buf[0]))
+ pubkeydata := (*C.uchar)(unsafe.Pointer(&pubkey[0]))
+ if C.secp256k1_decompress_pubkey(context, bufdata, pubkeydata) == 0 {
+ return nil, nil
+ }
+ return new(big.Int).SetBytes(buf[1:33]), new(big.Int).SetBytes(buf[33:])
+}
+
func checkSignature(sig []byte) error {
if len(sig) != 65 {
return ErrInvalidSignatureLen
diff --git a/crypto/signature_cgo.go b/crypto/signature_cgo.go
index feec5e7be..381d8a1bb 100644
--- a/crypto/signature_cgo.go
+++ b/crypto/signature_cgo.go
@@ -27,10 +27,12 @@ import (
"github.com/ethereum/go-ethereum/crypto/secp256k1"
)
+// Ecrecover returns the uncompressed public key that created the given signature.
func Ecrecover(hash, sig []byte) ([]byte, error) {
return secp256k1.RecoverPubkey(hash, sig)
}
+// SigToPub returns the public key that created the given signature.
func SigToPub(hash, sig []byte) (*ecdsa.PublicKey, error) {
s, err := Ecrecover(hash, sig)
if err != nil {
@@ -58,6 +60,22 @@ func Sign(hash []byte, prv *ecdsa.PrivateKey) (sig []byte, err error) {
return secp256k1.Sign(hash, seckey)
}
+// VerifySignature checks that the given public key created signature over hash.
+// The public key should be in compressed (33 bytes) or uncompressed (65 bytes) format.
+// The signature should have the 64 byte [R || S] format.
+func VerifySignature(pubkey, hash, signature []byte) bool {
+ return secp256k1.VerifySignature(pubkey, hash, signature)
+}
+
+// DecompressPubkey parses a public key in the 33-byte compressed format.
+func DecompressPubkey(pubkey []byte) (*ecdsa.PublicKey, error) {
+ x, y := secp256k1.DecompressPubkey(pubkey)
+ if x == nil {
+ return nil, fmt.Errorf("invalid public key")
+ }
+ return &ecdsa.PublicKey{X: x, Y: y, Curve: S256()}, nil
+}
+
// S256 returns an instance of the secp256k1 curve.
func S256() elliptic.Curve {
return secp256k1.S256()
diff --git a/crypto/signature_nocgo.go b/crypto/signature_nocgo.go
index a022eef9a..17fd613b2 100644
--- a/crypto/signature_nocgo.go
+++ b/crypto/signature_nocgo.go
@@ -21,11 +21,14 @@ package crypto
import (
"crypto/ecdsa"
"crypto/elliptic"
+ "errors"
"fmt"
+ "math/big"
"github.com/btcsuite/btcd/btcec"
)
+// Ecrecover returns the uncompressed public key that created the given signature.
func Ecrecover(hash, sig []byte) ([]byte, error) {
pub, err := SigToPub(hash, sig)
if err != nil {
@@ -35,6 +38,7 @@ func Ecrecover(hash, sig []byte) ([]byte, error) {
return bytes, err
}
+// SigToPub returns the public key that created the given signature.
func SigToPub(hash, sig []byte) (*ecdsa.PublicKey, error) {
// Convert to btcec input format with 'recovery id' v at the beginning.
btcsig := make([]byte, 65)
@@ -71,6 +75,33 @@ func Sign(hash []byte, prv *ecdsa.PrivateKey) ([]byte, error) {
return sig, nil
}
+// VerifySignature checks that the given public key created signature over hash.
+// The public key should be in compressed (33 bytes) or uncompressed (65 bytes) format.
+// The signature should have the 64 byte [R || S] format.
+func VerifySignature(pubkey, hash, signature []byte) bool {
+ if len(signature) != 64 {
+ return false
+ }
+ sig := &btcec.Signature{R: new(big.Int).SetBytes(signature[:32]), S: new(big.Int).SetBytes(signature[32:])}
+ key, err := btcec.ParsePubKey(pubkey, btcec.S256())
+ if err != nil {
+ return false
+ }
+ return sig.Verify(hash, key)
+}
+
+// DecompressPubkey parses a public key in the 33-byte compressed format.
+func DecompressPubkey(pubkey []byte) (*ecdsa.PublicKey, error) {
+ if len(pubkey) != 33 {
+ return nil, errors.New("invalid compressed public key length")
+ }
+ key, err := btcec.ParsePubKey(pubkey, btcec.S256())
+ if err != nil {
+ return nil, err
+ }
+ return key.ToECDSA(), nil
+}
+
// S256 returns an instance of the secp256k1 curve.
func S256() elliptic.Curve {
return btcec.S256()
diff --git a/crypto/signature_test.go b/crypto/signature_test.go
index aefd9e38d..abcab425b 100644
--- a/crypto/signature_test.go
+++ b/crypto/signature_test.go
@@ -18,19 +18,95 @@ package crypto
import (
"bytes"
- "encoding/hex"
"testing"
+
+ "github.com/ethereum/go-ethereum/common"
+ "github.com/ethereum/go-ethereum/common/hexutil"
+)
+
+var (
+ testmsg = hexutil.MustDecode("0xce0677bb30baa8cf067c88db9811f4333d131bf8bcf12fe7065d211dce971008")
+ testsig = hexutil.MustDecode("0x90f27b8b488db00b00606796d2987f6a5f59ae62ea05effe84fef5b8b0e549984a691139ad57a3f0b906637673aa2f63d1f55cb1a69199d4009eea23ceaddc9301")
+ testpubkey = hexutil.MustDecode("0x04e32df42865e97135acfb65f3bae71bdc86f4d49150ad6a440b6f15878109880a0a2b2667f7e725ceea70c673093bf67663e0312623c8e091b13cf2c0f11ef652")
+ testpubkeyc = hexutil.MustDecode("0x02e32df42865e97135acfb65f3bae71bdc86f4d49150ad6a440b6f15878109880a")
)
-func TestRecoverSanity(t *testing.T) {
- msg, _ := hex.DecodeString("ce0677bb30baa8cf067c88db9811f4333d131bf8bcf12fe7065d211dce971008")
- sig, _ := hex.DecodeString("90f27b8b488db00b00606796d2987f6a5f59ae62ea05effe84fef5b8b0e549984a691139ad57a3f0b906637673aa2f63d1f55cb1a69199d4009eea23ceaddc9301")
- pubkey1, _ := hex.DecodeString("04e32df42865e97135acfb65f3bae71bdc86f4d49150ad6a440b6f15878109880a0a2b2667f7e725ceea70c673093bf67663e0312623c8e091b13cf2c0f11ef652")
- pubkey2, err := Ecrecover(msg, sig)
+func TestEcrecover(t *testing.T) {
+ pubkey, err := Ecrecover(testmsg, testsig)
if err != nil {
t.Fatalf("recover error: %s", err)
}
- if !bytes.Equal(pubkey1, pubkey2) {
- t.Errorf("pubkey mismatch: want: %x have: %x", pubkey1, pubkey2)
+ if !bytes.Equal(pubkey, testpubkey) {
+ t.Errorf("pubkey mismatch: want: %x have: %x", testpubkey, pubkey)
+ }
+}
+
+func TestVerifySignature(t *testing.T) {
+ sig := testsig[:len(testsig)-1] // remove recovery id
+ if !VerifySignature(testpubkey, testmsg, sig) {
+ t.Errorf("can't verify signature with uncompressed key")
+ }
+ if !VerifySignature(testpubkeyc, testmsg, sig) {
+ t.Errorf("can't verify signature with compressed key")
+ }
+
+ if VerifySignature(nil, testmsg, sig) {
+ t.Errorf("signature valid with no key")
+ }
+ if VerifySignature(testpubkey, nil, sig) {
+ t.Errorf("signature valid with no message")
+ }
+ if VerifySignature(testpubkey, testmsg, nil) {
+ t.Errorf("nil signature valid")
+ }
+ if VerifySignature(testpubkey, testmsg, append(common.CopyBytes(sig), 1, 2, 3)) {
+ t.Errorf("signature valid with extra bytes at the end")
+ }
+ if VerifySignature(testpubkey, testmsg, sig[:len(sig)-2]) {
+ t.Errorf("signature valid even though it's incomplete")
+ }
+}
+
+func TestDecompressPubkey(t *testing.T) {
+ key, err := DecompressPubkey(testpubkeyc)
+ if err != nil {
+ t.Fatal(err)
+ }
+ if uncompressed := FromECDSAPub(key); !bytes.Equal(uncompressed, testpubkey) {
+ t.Errorf("wrong public key result: got %x, want %x", uncompressed, testpubkey)
+ }
+ if _, err := DecompressPubkey(nil); err == nil {
+ t.Errorf("no error for nil pubkey")
+ }
+ if _, err := DecompressPubkey(testpubkeyc[:5]); err == nil {
+ t.Errorf("no error for incomplete pubkey")
+ }
+ if _, err := DecompressPubkey(append(common.CopyBytes(testpubkeyc), 1, 2, 3)); err == nil {
+ t.Errorf("no error for pubkey with extra bytes at the end")
+ }
+}
+
+func BenchmarkEcrecoverSignature(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ if _, err := Ecrecover(testmsg, testsig); err != nil {
+ b.Fatal("ecrecover error", err)
+ }
+ }
+}
+
+func BenchmarkVerifySignature(b *testing.B) {
+ sig := testsig[:len(testsig)-1] // remove recovery id
+ for i := 0; i < b.N; i++ {
+ if !VerifySignature(testpubkey, testmsg, sig) {
+ b.Fatal("verify error")
+ }
+ }
+}
+
+func BenchmarkDecompressPubkey(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ if _, err := DecompressPubkey(testpubkeyc); err != nil {
+ b.Fatal(err)
+ }
}
}