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crypto, crypto/ecies, crypto/secp256k1: libsecp256k1 scalar mult

Browse Source 
thanks to Felix Lange (fjl) for help with design & impl
This commit is contained in:
Gustav Simonsson 2015-09-29 19:37:44 +02:00
parent 27a50c8f4b
commit c8ad64f33c
16 changed files with 321 additions and 171 deletions
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26
crypto/crypto.go
View File

@ -43,14 +43,6 @@ import (
"golang.org/x/crypto/ripemd160"
)
var secp256k1n *big.Int
func init() {
// specify the params for the s256 curve
ecies.AddParamsForCurve(S256(), ecies.ECIES_AES128_SHA256)
secp256k1n = common.String2Big("0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141")
}
func Sha3(data ...[]byte) []byte {
d := sha3.NewKeccak256()
for _, b := range data {
@ -99,9 +91,9 @@ func ToECDSA(prv []byte) *ecdsa.PrivateKey {
}
priv := new(ecdsa.PrivateKey)
priv.PublicKey.Curve = S256()
priv.PublicKey.Curve = secp256k1.S256()
priv.D = common.BigD(prv)
priv.PublicKey.X, priv.PublicKey.Y = S256().ScalarBaseMult(prv)
priv.PublicKey.X, priv.PublicKey.Y = secp256k1.S256().ScalarBaseMult(prv)
return priv
}
@ -116,15 +108,15 @@ func ToECDSAPub(pub []byte) *ecdsa.PublicKey {
if len(pub) == 0 {
return nil
}
x, y := elliptic.Unmarshal(S256(), pub)
return &ecdsa.PublicKey{S256(), x, y}
x, y := elliptic.Unmarshal(secp256k1.S256(), pub)
return &ecdsa.PublicKey{secp256k1.S256(), x, y}
}
func FromECDSAPub(pub *ecdsa.PublicKey) []byte {
if pub == nil || pub.X == nil || pub.Y == nil {
return nil
}
return elliptic.Marshal(S256(), pub.X, pub.Y)
return elliptic.Marshal(secp256k1.S256(), pub.X, pub.Y)
}
// HexToECDSA parses a secp256k1 private key.
@ -168,7 +160,7 @@ func SaveECDSA(file string, key *ecdsa.PrivateKey) error {
}
func GenerateKey() (*ecdsa.PrivateKey, error) {
return ecdsa.GenerateKey(S256(), rand.Reader)
return ecdsa.GenerateKey(secp256k1.S256(), rand.Reader)
}
func ValidateSignatureValues(v byte, r, s *big.Int) bool {
@ -176,7 +168,7 @@ func ValidateSignatureValues(v byte, r, s *big.Int) bool {
return false
}
vint := uint32(v)
if r.Cmp(secp256k1n) < 0 && s.Cmp(secp256k1n) < 0 && (vint == 27 || vint == 28) {
if r.Cmp(secp256k1.N) < 0 && s.Cmp(secp256k1.N) < 0 && (vint == 27 || vint == 28) {
return true
} else {
return false
@ -189,8 +181,8 @@ func SigToPub(hash, sig []byte) (*ecdsa.PublicKey, error) {
return nil, err
}
x, y := elliptic.Unmarshal(S256(), s)
return &ecdsa.PublicKey{S256(), x, y}, nil
x, y := elliptic.Unmarshal(secp256k1.S256(), s)
return &ecdsa.PublicKey{secp256k1.S256(), x, y}, nil
}
func Sign(hash []byte, prv *ecdsa.PrivateKey) (sig []byte, err error) {

8
crypto/crypto_test.go
View File

@ -181,7 +181,7 @@ func TestValidateSignatureValues(t *testing.T) {
minusOne := big.NewInt(-1)
one := common.Big1
zero := common.Big0
secp256k1nMinus1 := new(big.Int).Sub(secp256k1n, common.Big1)
secp256k1nMinus1 := new(big.Int).Sub(secp256k1.N, common.Big1)
// correct v,r,s
check(true, 27, one, one)
@ -208,9 +208,9 @@ func TestValidateSignatureValues(t *testing.T) {
// correct sig with max r,s
check(true, 27, secp256k1nMinus1, secp256k1nMinus1)
// correct v, combinations of incorrect r,s at upper limit
check(false, 27, secp256k1n, secp256k1nMinus1)
check(false, 27, secp256k1nMinus1, secp256k1n)
check(false, 27, secp256k1n, secp256k1n)
check(false, 27, secp256k1.N, secp256k1nMinus1)
check(false, 27, secp256k1nMinus1, secp256k1.N)
check(false, 27, secp256k1.N, secp256k1.N)
// current callers ensures r,s cannot be negative, but let's test for that too
// as crypto package could be used stand-alone

7
crypto/ecies/asn1.go
View File

@ -41,6 +41,8 @@ import (
"fmt"
"hash"
"math/big"
"github.com/ethereum/go-ethereum/crypto/secp256k1"
)
var (
@ -81,6 +83,7 @@ func doScheme(base, v []int) asn1.ObjectIdentifier {
type secgNamedCurve asn1.ObjectIdentifier
var (
secgNamedCurveS256 = secgNamedCurve{1, 3, 132, 0, 10}
secgNamedCurveP256 = secgNamedCurve{1, 2, 840, 10045, 3, 1, 7}
secgNamedCurveP384 = secgNamedCurve{1, 3, 132, 0, 34}
secgNamedCurveP521 = secgNamedCurve{1, 3, 132, 0, 35}
@ -116,6 +119,8 @@ func (curve secgNamedCurve) Equal(curve2 secgNamedCurve) bool {
func namedCurveFromOID(curve secgNamedCurve) elliptic.Curve {
switch {
case curve.Equal(secgNamedCurveS256):
return secp256k1.S256()
case curve.Equal(secgNamedCurveP256):
return elliptic.P256()
case curve.Equal(secgNamedCurveP384):
@ -134,6 +139,8 @@ func oidFromNamedCurve(curve elliptic.Curve) (secgNamedCurve, bool) {
return secgNamedCurveP384, true
case elliptic.P521():
return secgNamedCurveP521, true
case secp256k1.S256():
return secgNamedCurveS256, true
}
return nil, false

1
crypto/ecies/ecies.go
View File

@ -125,6 +125,7 @@ func (prv *PrivateKey) GenerateShared(pub *PublicKey, skLen, macLen int) (sk []b
if skLen+macLen > MaxSharedKeyLength(pub) {
return nil, ErrSharedKeyTooBig
}
x, _ := pub.Curve.ScalarMult(pub.X, pub.Y, prv.D.Bytes())
if x == nil {
return nil, ErrSharedKeyIsPointAtInfinity

123
crypto/ecies/ecies_test.go
View File

@ -31,13 +31,18 @@ package ecies
import (
"bytes"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/sha256"
"encoding/hex"
"flag"
"fmt"
"io/ioutil"
"math/big"
"testing"
"github.com/ethereum/go-ethereum/crypto/secp256k1"
)
var dumpEnc bool
@ -65,7 +70,6 @@ func TestKDF(t *testing.T) {
}
}
var skLen int
var ErrBadSharedKeys = fmt.Errorf("ecies: shared keys don't match")
// cmpParams compares a set of ECIES parameters. We assume, as per the
@ -117,7 +121,7 @@ func TestSharedKey(t *testing.T) {
fmt.Println(err.Error())
t.FailNow()
}
skLen = MaxSharedKeyLength(&prv1.PublicKey) / 2
skLen := MaxSharedKeyLength(&prv1.PublicKey) / 2
prv2, err := GenerateKey(rand.Reader, DefaultCurve, nil)
if err != nil {
@ -143,6 +147,44 @@ func TestSharedKey(t *testing.T) {
}
}
func TestSharedKeyPadding(t *testing.T) {
// sanity checks
prv0 := hexKey("1adf5c18167d96a1f9a0b1ef63be8aa27eaf6032c233b2b38f7850cf5b859fd9")
prv1 := hexKey("97a076fc7fcd9208240668e31c9abee952cbb6e375d1b8febc7499d6e16f1a")
x0, _ := new(big.Int).SetString("1a8ed022ff7aec59dc1b440446bdda5ff6bcb3509a8b109077282b361efffbd8", 16)
x1, _ := new(big.Int).SetString("6ab3ac374251f638d0abb3ef596d1dc67955b507c104e5f2009724812dc027b8", 16)
y0, _ := new(big.Int).SetString("e040bd480b1deccc3bc40bd5b1fdcb7bfd352500b477cb9471366dbd4493f923", 16)
y1, _ := new(big.Int).SetString("8ad915f2b503a8be6facab6588731fefeb584fd2dfa9a77a5e0bba1ec439e4fa", 16)
if prv0.PublicKey.X.Cmp(x0) != 0 {
t.Errorf("mismatched prv0.X:\nhave: %x\nwant: %x\n", prv0.PublicKey.X.Bytes(), x0.Bytes())
}
if prv0.PublicKey.Y.Cmp(y0) != 0 {
t.Errorf("mismatched prv0.Y:\nhave: %x\nwant: %x\n", prv0.PublicKey.Y.Bytes(), y0.Bytes())
}
if prv1.PublicKey.X.Cmp(x1) != 0 {
t.Errorf("mismatched prv1.X:\nhave: %x\nwant: %x\n", prv1.PublicKey.X.Bytes(), x1.Bytes())
}
if prv1.PublicKey.Y.Cmp(y1) != 0 {
t.Errorf("mismatched prv1.Y:\nhave: %x\nwant: %x\n", prv1.PublicKey.Y.Bytes(), y1.Bytes())
}
// test shared secret generation
sk1, err := prv0.GenerateShared(&prv1.PublicKey, 16, 16)
if err != nil {
fmt.Println(err.Error())
}
sk2, err := prv1.GenerateShared(&prv0.PublicKey, 16, 16)
if err != nil {
t.Fatal(err.Error())
}
if !bytes.Equal(sk1, sk2) {
t.Fatal(ErrBadSharedKeys.Error())
}
}
// Verify that the key generation code fails when too much key data is
// requested.
func TestTooBigSharedKey(t *testing.T) {
@ -158,13 +200,13 @@ func TestTooBigSharedKey(t *testing.T) {
t.FailNow()
}
_, err = prv1.GenerateShared(&prv2.PublicKey, skLen*2, skLen*2)
_, err = prv1.GenerateShared(&prv2.PublicKey, 32, 32)
if err != ErrSharedKeyTooBig {
fmt.Println("ecdh: shared key should be too large for curve")
t.FailNow()
}
_, err = prv2.GenerateShared(&prv1.PublicKey, skLen*2, skLen*2)
_, err = prv2.GenerateShared(&prv1.PublicKey, 32, 32)
if err != ErrSharedKeyTooBig {
fmt.Println("ecdh: shared key should be too large for curve")
t.FailNow()
@ -176,25 +218,21 @@ func TestTooBigSharedKey(t *testing.T) {
func TestMarshalPublic(t *testing.T) {
prv, err := GenerateKey(rand.Reader, DefaultCurve, nil)
if err != nil {
fmt.Println(err.Error())
t.FailNow()
t.Fatalf("GenerateKey error: %s", err)
}
out, err := MarshalPublic(&prv.PublicKey)
if err != nil {
fmt.Println(err.Error())
t.FailNow()
t.Fatalf("MarshalPublic error: %s", err)
}
pub, err := UnmarshalPublic(out)
if err != nil {
fmt.Println(err.Error())
t.FailNow()
t.Fatalf("UnmarshalPublic error: %s", err)
}
if !cmpPublic(prv.PublicKey, *pub) {
fmt.Println("ecies: failed to unmarshal public key")
t.FailNow()
t.Fatal("ecies: failed to unmarshal public key")
}
}
@ -304,9 +342,26 @@ func BenchmarkGenSharedKeyP256(b *testing.B) {
fmt.Println(err.Error())
b.FailNow()
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
_, err := prv.GenerateShared(&prv.PublicKey, skLen, skLen)
_, err := prv.GenerateShared(&prv.PublicKey, 16, 16)
if err != nil {
fmt.Println(err.Error())
b.FailNow()
}
}
}
// Benchmark the generation of S256 shared keys.
func BenchmarkGenSharedKeyS256(b *testing.B) {
prv, err := GenerateKey(rand.Reader, secp256k1.S256(), nil)
if err != nil {
fmt.Println(err.Error())
b.FailNow()
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
_, err := prv.GenerateShared(&prv.PublicKey, 16, 16)
if err != nil {
fmt.Println(err.Error())
b.FailNow()
@ -511,3 +566,43 @@ func TestBasicKeyValidation(t *testing.T) {
}
}
}
// Verify GenerateShared against static values - useful when
// debugging changes in underlying libs
func TestSharedKeyStatic(t *testing.T) {
prv1 := hexKey("7ebbc6a8358bc76dd73ebc557056702c8cfc34e5cfcd90eb83af0347575fd2ad")
prv2 := hexKey("6a3d6396903245bba5837752b9e0348874e72db0c4e11e9c485a81b4ea4353b9")
skLen := MaxSharedKeyLength(&prv1.PublicKey) / 2
sk1, err := prv1.GenerateShared(&prv2.PublicKey, skLen, skLen)
if err != nil {
fmt.Println(err.Error())
t.FailNow()
}
sk2, err := prv2.GenerateShared(&prv1.PublicKey, skLen, skLen)
if err != nil {
fmt.Println(err.Error())
t.FailNow()
}
if !bytes.Equal(sk1, sk2) {
fmt.Println(ErrBadSharedKeys.Error())
t.FailNow()
}
sk, _ := hex.DecodeString("167ccc13ac5e8a26b131c3446030c60fbfac6aa8e31149d0869f93626a4cdf62")
if !bytes.Equal(sk1, sk) {
t.Fatalf("shared secret mismatch: want: %x have: %x", sk, sk1)
}
}
// TODO: remove after refactoring packages crypto and crypto/ecies
func hexKey(prv string) *PrivateKey {
priv := new(ecdsa.PrivateKey)
priv.PublicKey.Curve = secp256k1.S256()
priv.D, _ = new(big.Int).SetString(prv, 16)
priv.PublicKey.X, priv.PublicKey.Y = secp256k1.S256().ScalarBaseMult(priv.D.Bytes())
return ImportECDSA(priv)
}

14
crypto/ecies/params.go
View File

@ -41,13 +41,12 @@ import (
"crypto/sha512"
"fmt"
"hash"
"github.com/ethereum/go-ethereum/crypto/secp256k1"
)
// The default curve for this package is the NIST P256 curve, which
// provides security equivalent to AES-128.
var DefaultCurve = elliptic.P256()
var (
DefaultCurve = secp256k1.S256()
ErrUnsupportedECDHAlgorithm = fmt.Errorf("ecies: unsupported ECDH algorithm")
ErrUnsupportedECIESParameters = fmt.Errorf("ecies: unsupported ECIES parameters")
)
@ -101,9 +100,10 @@ var (
)
var paramsFromCurve = map[elliptic.Curve]*ECIESParams{
elliptic.P256(): ECIES_AES128_SHA256,
elliptic.P384(): ECIES_AES256_SHA384,
elliptic.P521(): ECIES_AES256_SHA512,
secp256k1.S256(): ECIES_AES128_SHA256,
elliptic.P256(): ECIES_AES128_SHA256,
elliptic.P384(): ECIES_AES256_SHA384,
elliptic.P521(): ECIES_AES256_SHA512,
}
func AddParamsForCurve(curve elliptic.Curve, params *ECIESParams) {

5
crypto/key.go
View File

@ -25,6 +25,7 @@ import (
"strings"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto/secp256k1"
"github.com/pborman/uuid"
)
@ -137,7 +138,7 @@ func NewKey(rand io.Reader) *Key {
panic("key generation: could not read from random source: " + err.Error())
}
reader := bytes.NewReader(randBytes)
privateKeyECDSA, err := ecdsa.GenerateKey(S256(), reader)
privateKeyECDSA, err := ecdsa.GenerateKey(secp256k1.S256(), reader)
if err != nil {
panic("key generation: ecdsa.GenerateKey failed: " + err.Error())
}
@ -155,7 +156,7 @@ func NewKeyForDirectICAP(rand io.Reader) *Key {
panic("key generation: could not read from random source: " + err.Error())
}
reader := bytes.NewReader(randBytes)
privateKeyECDSA, err := ecdsa.GenerateKey(S256(), reader)
privateKeyECDSA, err := ecdsa.GenerateKey(secp256k1.S256(), reader)
if err != nil {
panic("key generation: ecdsa.GenerateKey failed: " + err.Error())
}

166
crypto/curve.go → crypto/secp256k1/curve.go
View File

@ -29,15 +29,22 @@
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package crypto
package secp256k1
import (
"crypto/elliptic"
"io"
"math/big"
"sync"
"unsafe"
)
/*
#include "libsecp256k1/include/secp256k1.h"
extern int secp256k1_pubkey_scalar_mul(const secp256k1_context* ctx, const unsigned char *point, const unsigned char *scalar);
*/
import "C"
// This code is from https://github.com/ThePiachu/GoBit and implements
// several Koblitz elliptic curves over prime fields.
//
@ -211,44 +218,37 @@ func (BitCurve *BitCurve) doubleJacobian(x, y, z *big.Int) (*big.Int, *big.Int,
return x3, y3, z3
}
//TODO: double check if it is okay
// ScalarMult returns k*(Bx,By) where k is a number in big-endian form.
func (BitCurve *BitCurve) ScalarMult(Bx, By *big.Int, k []byte) (*big.Int, *big.Int) {
// We have a slight problem in that the identity of the group (the
// point at infinity) cannot be represented in (x, y) form on a finite
// machine. Thus the standard add/double algorithm has to be tweaked
// slightly: our initial state is not the identity, but x, and we
// ignore the first true bit in |k|. If we don't find any true bits in
// |k|, then we return nil, nil, because we cannot return the identity
// element.
Bz := new(big.Int).SetInt64(1)
x := Bx
y := By
z := Bz
seenFirstTrue := false
for _, byte := range k {
for bitNum := 0; bitNum < 8; bitNum++ {
if seenFirstTrue {
x, y, z = BitCurve.doubleJacobian(x, y, z)
}
if byte&0x80 == 0x80 {
if !seenFirstTrue {
seenFirstTrue = true
} else {
x, y, z = BitCurve.addJacobian(Bx, By, Bz, x, y, z)
}
}
byte <<= 1
}
func (BitCurve *BitCurve) ScalarMult(Bx, By *big.Int, scalar []byte) (*big.Int, *big.Int) {
// Ensure scalar is exactly 32 bytes. We pad always, even if
// scalar is 32 bytes long, to avoid a timing side channel.
if len(scalar) > 32 {
panic("can't handle scalars > 256 bits")
}
padded := make([]byte, 32)
copy(padded[32-len(scalar):], scalar)
scalar = padded
if !seenFirstTrue {
// Do the multiplication in C, updating point.
point := make([]byte, 64)
readBits(point[:32], Bx)
readBits(point[32:], By)
pointPtr := (*C.uchar)(unsafe.Pointer(&point[0]))
scalarPtr := (*C.uchar)(unsafe.Pointer(&scalar[0]))
res := C.secp256k1_pubkey_scalar_mul(context, pointPtr, scalarPtr)
// Unpack the result and clear temporaries.
x := new(big.Int).SetBytes(point[:32])
y := new(big.Int).SetBytes(point[32:])
for i := range point {
point[i] = 0
}
for i := range padded {
scalar[i] = 0
}
if res != 1 {
return nil, nil
}
return BitCurve.affineFromJacobian(x, y, z)
return x, y
}
// ScalarBaseMult returns k*G, where G is the base point of the group and k is
@ -312,86 +312,24 @@ func (BitCurve *BitCurve) Unmarshal(data []byte) (x, y *big.Int) {
return
}
//curve parameters taken from:
//http://www.secg.org/collateral/sec2_final.pdf
var initonce sync.Once
var ecp160k1 *BitCurve
var ecp192k1 *BitCurve
var ecp224k1 *BitCurve
var ecp256k1 *BitCurve
func initAll() {
initS160()
initS192()
initS224()
initS256()
}
func initS160() {
// See SEC 2 section 2.4.1
ecp160k1 = new(BitCurve)
ecp160k1.P, _ = new(big.Int).SetString("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFAC73", 16)
ecp160k1.N, _ = new(big.Int).SetString("0100000000000000000001B8FA16DFAB9ACA16B6B3", 16)
ecp160k1.B, _ = new(big.Int).SetString("0000000000000000000000000000000000000007", 16)
ecp160k1.Gx, _ = new(big.Int).SetString("3B4C382CE37AA192A4019E763036F4F5DD4D7EBB", 16)
ecp160k1.Gy, _ = new(big.Int).SetString("938CF935318FDCED6BC28286531733C3F03C4FEE", 16)
ecp160k1.BitSize = 160
}
func initS192() {
// See SEC 2 section 2.5.1
ecp192k1 = new(BitCurve)
ecp192k1.P, _ = new(big.Int).SetString("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFEE37", 16)
ecp192k1.N, _ = new(big.Int).SetString("FFFFFFFFFFFFFFFFFFFFFFFE26F2FC170F69466A74DEFD8D", 16)
ecp192k1.B, _ = new(big.Int).SetString("000000000000000000000000000000000000000000000003", 16)
ecp192k1.Gx, _ = new(big.Int).SetString("DB4FF10EC057E9AE26B07D0280B7F4341DA5D1B1EAE06C7D", 16)
ecp192k1.Gy, _ = new(big.Int).SetString("9B2F2F6D9C5628A7844163D015BE86344082AA88D95E2F9D", 16)
ecp192k1.BitSize = 192
}
func initS224() {
// See SEC 2 section 2.6.1
ecp224k1 = new(BitCurve)
ecp224k1.P, _ = new(big.Int).SetString("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFE56D", 16)
ecp224k1.N, _ = new(big.Int).SetString("010000000000000000000000000001DCE8D2EC6184CAF0A971769FB1F7", 16)
ecp224k1.B, _ = new(big.Int).SetString("00000000000000000000000000000000000000000000000000000005", 16)
ecp224k1.Gx, _ = new(big.Int).SetString("A1455B334DF099DF30FC28A169A467E9E47075A90F7E650EB6B7A45C", 16)
ecp224k1.Gy, _ = new(big.Int).SetString("7E089FED7FBA344282CAFBD6F7E319F7C0B0BD59E2CA4BDB556D61A5", 16)
ecp224k1.BitSize = 224
}
func initS256() {
// See SEC 2 section 2.7.1
ecp256k1 = new(BitCurve)
ecp256k1.P, _ = new(big.Int).SetString("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F", 16)
ecp256k1.N, _ = new(big.Int).SetString("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141", 16)
ecp256k1.B, _ = new(big.Int).SetString("0000000000000000000000000000000000000000000000000000000000000007", 16)
ecp256k1.Gx, _ = new(big.Int).SetString("79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798", 16)
ecp256k1.Gy, _ = new(big.Int).SetString("483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8", 16)
ecp256k1.BitSize = 256
}
// S160 returns a BitCurve which implements secp160k1 (see SEC 2 section 2.4.1)
func S160() *BitCurve {
initonce.Do(initAll)
return ecp160k1
}
// S192 returns a BitCurve which implements secp192k1 (see SEC 2 section 2.5.1)
func S192() *BitCurve {
initonce.Do(initAll)
return ecp192k1
}
// S224 returns a BitCurve which implements secp224k1 (see SEC 2 section 2.6.1)
func S224() *BitCurve {
initonce.Do(initAll)
return ecp224k1
}
var (
initonce sync.Once
theCurve *BitCurve
)
// S256 returns a BitCurve which implements secp256k1 (see SEC 2 section 2.7.1)
func S256() *BitCurve {
initonce.Do(initAll)
return ecp256k1
initonce.Do(func() {
// See SEC 2 section 2.7.1
// curve parameters taken from:
// http://www.secg.org/collateral/sec2_final.pdf
theCurve = new(BitCurve)
theCurve.P, _ = new(big.Int).SetString("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F", 16)
theCurve.N, _ = new(big.Int).SetString("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141", 16)
theCurve.B, _ = new(big.Int).SetString("0000000000000000000000000000000000000000000000000000000000000007", 16)
theCurve.Gx, _ = new(big.Int).SetString("79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798", 16)
theCurve.Gy, _ = new(big.Int).SetString("483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8", 16)
theCurve.BitSize = 256
})
return theCurve
}

39
crypto/secp256k1/curve_test.go Normal file
View File

@ -0,0 +1,39 @@
// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package secp256k1
import (
"bytes"
"encoding/hex"
"math/big"
"testing"
)
func TestReadBits(t *testing.T) {
check := func(input string) {
want, _ := hex.DecodeString(input)
int, _ := new(big.Int).SetString(input, 16)
buf := make([]byte, len(want))
readBits(buf, int)
if !bytes.Equal(buf, want) {
t.Errorf("have: %x\nwant: %x", buf, want)
}
}
check("000000000000000000000000000000000000000000000000000000FEFCF3F8F0")
check("0000000000012345000000000000000000000000000000000000FEFCF3F8F0")
check("18F8F8F1000111000110011100222004330052300000000000000000FEFCF3F8F0")
}

56
crypto/secp256k1/pubkey_scalar_mul.h Normal file
View File

@ -0,0 +1,56 @@
// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
/** Multiply point by scalar in constant time.
* Returns: 1: multiplication was successful
* 0: scalar was invalid (zero or overflow)
* Args: ctx: pointer to a context object (cannot be NULL)
* Out: point: the multiplied point (usually secret)
* In: point: pointer to a 64-byte bytepublic point,
encoded as two 256bit big-endian numbers.
* scalar: a 32-byte scalar with which to multiply the point
*/
int secp256k1_pubkey_scalar_mul(const secp256k1_context* ctx, unsigned char *point, const unsigned char *scalar) {
int ret = 0;
int overflow = 0;
secp256k1_fe feX, feY;
secp256k1_gej res;
secp256k1_ge ge;
secp256k1_scalar s;
ARG_CHECK(point != NULL);
ARG_CHECK(scalar != NULL);
(void)ctx;
secp256k1_fe_set_b32(&feX, point);
secp256k1_fe_set_b32(&feY, point+32);
secp256k1_ge_set_xy(&ge, &feX, &feY);
secp256k1_scalar_set_b32(&s, scalar, &overflow);
if (overflow || secp256k1_scalar_is_zero(&s)) {
ret = 0;
} else {
secp256k1_ecmult_const(&res, &ge, &s);
secp256k1_ge_set_gej(&ge, &res);
/* Note: can't use secp256k1_pubkey_save here because it is not constant time. */
secp256k1_fe_normalize(&ge.x);
secp256k1_fe_normalize(&ge.y);
secp256k1_fe_get_b32(point, &ge.x);
secp256k1_fe_get_b32(point+32, &ge.y);
ret = 1;
}
secp256k1_scalar_clear(&s);
return ret;
}

28
crypto/secp256k1/secp256.go
View File

@ -20,6 +20,7 @@ package secp256k1
/*
#cgo CFLAGS: -I./libsecp256k1
#cgo CFLAGS: -I./libsecp256k1/src/
#cgo darwin CFLAGS: -I/usr/local/include
#cgo freebsd CFLAGS: -I/usr/local/include
#cgo linux,arm CFLAGS: -I/usr/local/arm/include
@ -35,6 +36,7 @@ package secp256k1
#define NDEBUG
#include "./libsecp256k1/src/secp256k1.c"
#include "./libsecp256k1/src/modules/recovery/main_impl.h"
#include "pubkey_scalar_mul.h"
typedef void (*callbackFunc) (const char* msg, void* data);
extern void secp256k1GoPanicIllegal(const char* msg, void* data);
@ -44,6 +46,7 @@ import "C"
import (
"errors"
"math/big"
"unsafe"
"github.com/ethereum/go-ethereum/crypto/randentropy"
@ -56,13 +59,16 @@ import (
> store private keys in buffer and shuffle (deters persistance on swap disc)
> byte permutation (changing)
> xor with chaning random block (to deter scanning memory for 0x63) (stream cipher?)
> on disk: store keys in wallets
*/
// holds ptr to secp256k1_context_struct (see secp256k1/include/secp256k1.h)
var context *C.secp256k1_context
var (
context *C.secp256k1_context
N *big.Int
)
func init() {
N, _ = new(big.Int).SetString("fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141", 16)
// around 20 ms on a modern CPU.
context = C.secp256k1_context_create(3) // SECP256K1_START_SIGN | SECP256K1_START_VERIFY
C.secp256k1_context_set_illegal_callback(context, C.callbackFunc(C.secp256k1GoPanicIllegal), nil)
@ -78,7 +84,6 @@ var (
func GenerateKeyPair() ([]byte, []byte) {
var seckey []byte = randentropy.GetEntropyCSPRNG(32)
var seckey_ptr *C.uchar = (*C.uchar)(unsafe.Pointer(&seckey[0]))
var pubkey64 []byte = make([]byte, 64) // secp256k1_pubkey
var pubkey65 []byte = make([]byte, 65) // 65 byte uncompressed pubkey
pubkey64_ptr := (*C.secp256k1_pubkey)(unsafe.Pointer(&pubkey64[0]))
@ -96,7 +101,7 @@ func GenerateKeyPair() ([]byte, []byte) {
var output_len C.size_t
_ = C.secp256k1_ec_pubkey_serialize( // always returns 1
C.secp256k1_ec_pubkey_serialize( // always returns 1
context,
pubkey65_ptr,
&output_len,
@ -163,7 +168,7 @@ func Sign(msg []byte, seckey []byte) ([]byte, error) {
sig_serialized_ptr := (*C.uchar)(unsafe.Pointer(&sig_serialized[0]))
var recid C.int
_ = C.secp256k1_ecdsa_recoverable_signature_serialize_compact(
C.secp256k1_ecdsa_recoverable_signature_serialize_compact(
context,
sig_serialized_ptr, // 64 byte compact signature
&recid,
@ -254,3 +259,16 @@ func checkSignature(sig []byte) error {
}
return nil
}
// reads num into buf as big-endian bytes.
func readBits(buf []byte, num *big.Int) {
const wordLen = int(unsafe.Sizeof(big.Word(0)))
i := len(buf)
for _, d := range num.Bits() {
for j := 0; j < wordLen && i > 0; j++ {
i--
buf[i] = byte(d)
d >>= 8
}
}
}

2
crypto/secp256k1/secp256_test.go
View File

@ -24,7 +24,7 @@ import (
"github.com/ethereum/go-ethereum/crypto/randentropy"
)
const TestCount = 10000
const TestCount = 1000
func TestPrivkeyGenerate(t *testing.T) {
_, seckey := GenerateKeyPair()

2
p2p/discover/node.go
View File

@ -210,7 +210,7 @@ func PubkeyID(pub *ecdsa.PublicKey) NodeID {
// Pubkey returns the public key represented by the node ID.
// It returns an error if the ID is not a point on the curve.
func (id NodeID) Pubkey() (*ecdsa.PublicKey, error) {
p := &ecdsa.PublicKey{Curve: crypto.S256(), X: new(big.Int), Y: new(big.Int)}
p := &ecdsa.PublicKey{Curve: secp256k1.S256(), X: new(big.Int), Y: new(big.Int)}
half := len(id) / 2
p.X.SetBytes(id[:half])
p.Y.SetBytes(id[half:])

4
p2p/rlpx.go
View File

@ -277,7 +277,7 @@ func newInitiatorHandshake(remoteID discover.NodeID) (*encHandshake, error) {
return nil, err
}
// generate random keypair to use for signing
randpriv, err := ecies.GenerateKey(rand.Reader, crypto.S256(), nil)
randpriv, err := ecies.GenerateKey(rand.Reader, secp256k1.S256(), nil)
if err != nil {
return nil, err
}
@ -376,7 +376,7 @@ func decodeAuthMsg(prv *ecdsa.PrivateKey, token []byte, auth []byte) (*encHandsh
var err error
h := new(encHandshake)
// generate random keypair for session
h.randomPrivKey, err = ecies.GenerateKey(rand.Reader, crypto.S256(), nil)
h.randomPrivKey, err = ecies.GenerateKey(rand.Reader, secp256k1.S256(), nil)
if err != nil {
return nil, err
}

2
p2p/rlpx_test.go
View File

@ -93,6 +93,7 @@ func testEncHandshake(token []byte) error {
go func() {
r := result{side: "initiator"}
defer func() { output <- r }()
defer fd0.Close()
dest := &discover.Node{ID: discover.PubkeyID(&prv1.PublicKey)}
r.id, r.err = c0.doEncHandshake(prv0, dest)
@ -107,6 +108,7 @@ func testEncHandshake(token []byte) error {
go func() {
r := result{side: "receiver"}
defer func() { output <- r }()
defer fd1.Close()
r.id, r.err = c1.doEncHandshake(prv1, nil)
if r.err != nil {

9
whisper/message_test.go
View File

@ -23,6 +23,7 @@ import (
"time"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/crypto/secp256k1"
)
// Tests whether a message can be wrapped without any identity or encryption.
@ -72,8 +73,8 @@ func TestMessageCleartextSignRecover(t *testing.T) {
if pubKey == nil {
t.Fatalf("failed to recover public key")
}
p1 := elliptic.Marshal(crypto.S256(), key.PublicKey.X, key.PublicKey.Y)
p2 := elliptic.Marshal(crypto.S256(), pubKey.X, pubKey.Y)
p1 := elliptic.Marshal(secp256k1.S256(), key.PublicKey.X, key.PublicKey.Y)
p2 := elliptic.Marshal(secp256k1.S256(), pubKey.X, pubKey.Y)
if !bytes.Equal(p1, p2) {
t.Fatalf("public key mismatch: have 0x%x, want 0x%x", p2, p1)
}
@ -150,8 +151,8 @@ func TestMessageFullCrypto(t *testing.T) {
if pubKey == nil {
t.Fatalf("failed to recover public key")
}
p1 := elliptic.Marshal(crypto.S256(), fromKey.PublicKey.X, fromKey.PublicKey.Y)
p2 := elliptic.Marshal(crypto.S256(), pubKey.X, pubKey.Y)
p1 := elliptic.Marshal(secp256k1.S256(), fromKey.PublicKey.X, fromKey.PublicKey.Y)
p2 := elliptic.Marshal(secp256k1.S256(), pubKey.X, pubKey.Y)
if !bytes.Equal(p1, p2) {
t.Fatalf("public key mismatch: have 0x%x, want 0x%x", p2, p1)
}