forked from rubblelabs/ripple
/
ecdsa.go
88 lines (77 loc) · 1.97 KB
/
ecdsa.go
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package crypto
import (
"crypto/rand"
"encoding/binary"
"encoding/hex"
"math/big"
"github.com/btcsuite/btcd/btcec"
)
var (
order = btcec.S256().N
zero = big.NewInt(0)
one = big.NewInt(1)
)
type ecdsaKey struct {
*btcec.PrivateKey
}
func newKey(seed []byte) *btcec.PrivateKey {
inc := big.NewInt(0).SetBytes(seed)
inc.Lsh(inc, 32)
for key := big.NewInt(0); ; inc.Add(inc, one) {
key.SetBytes(Sha512Half(inc.Bytes()))
if key.Cmp(zero) > 0 && key.Cmp(order) < 0 {
privKey, _ := btcec.PrivKeyFromBytes(btcec.S256(), key.Bytes())
return privKey
}
}
}
func NewECDSAKeyFromString(p string) (*ecdsaKey, error) {
pk, err := hex.DecodeString(p)
if err != nil {
return nil, err
}
pvk, _ := btcec.PrivKeyFromBytes(btcec.S256(), pk)
r := &ecdsaKey{pvk}
return r, nil
}
func NewECDSAKeyFromPk(p *btcec.PrivateKey) *ecdsaKey {
r := &ecdsaKey{p}
return r
}
// If seed is nil, generate a random one
func NewECDSAKey(seed []byte) (*ecdsaKey, error) {
if seed == nil {
seed = make([]byte, 16)
if _, err := rand.Read(seed); err != nil {
return nil, err
}
}
return &ecdsaKey{newKey(seed)}, nil
}
func (k *ecdsaKey) generateKey(sequence uint32) *btcec.PrivateKey {
seed := make([]byte, btcec.PubKeyBytesLenCompressed+4)
copy(seed, k.PubKey().SerializeCompressed())
binary.BigEndian.PutUint32(seed[btcec.PubKeyBytesLenCompressed:], sequence)
key := newKey(seed)
key.D.Add(key.D, k.D).Mod(key.D, order)
key.X, key.Y = key.ScalarBaseMult(key.D.Bytes())
return key
}
func (k *ecdsaKey) Id(sequence *uint32) []byte {
if sequence == nil {
return Sha256RipeMD160(k.PubKey().SerializeCompressed())
}
return Sha256RipeMD160(k.Public(sequence))
}
func (k *ecdsaKey) Private(sequence *uint32) []byte {
if sequence == nil {
return k.D.Bytes()
}
return k.generateKey(*sequence).D.Bytes()
}
func (k *ecdsaKey) Public(sequence *uint32) []byte {
if sequence == nil {
return k.PubKey().SerializeCompressed()
}
return k.generateKey(*sequence).PubKey().SerializeCompressed()
}