neoneo-go/pkg/crypto/privatekey/privatekey.go
decentralisedkev f8979fe7af
Fix lint errors (#182)
* golint and minor changes to make code readable
2019-03-17 18:26:35 +00:00

125 lines
2.9 KiB
Go
Executable file

package privatekey
import (
"bytes"
"crypto/rand"
"crypto/sha256"
"encoding/hex"
"errors"
"fmt"
"io"
"math/big"
"github.com/CityOfZion/neo-go/pkg/crypto/publickey"
"github.com/CityOfZion/neo-go/pkg/crypto/base58"
"github.com/CityOfZion/neo-go/pkg/crypto/elliptic"
"github.com/CityOfZion/neo-go/pkg/crypto/hash"
"github.com/CityOfZion/neo-go/pkg/crypto/rfc6979"
)
// PrivateKey represents a NEO private key.
type PrivateKey struct {
b []byte
}
// NewPrivateKey will create a new private key
// With curve as Secp256r1
func NewPrivateKey() (*PrivateKey, error) {
curve := elliptic.NewEllipticCurve(elliptic.Secp256r1)
b := make([]byte, curve.N.BitLen()/8+8)
if _, err := io.ReadFull(rand.Reader, b); err != nil {
return nil, err
}
d := new(big.Int).SetBytes(b)
d.Mod(d, new(big.Int).Sub(curve.N, big.NewInt(1)))
d.Add(d, big.NewInt(1))
p := &PrivateKey{b: d.Bytes()}
return p, nil
}
// NewPrivateKeyFromHex will create a new private key hex string
func NewPrivateKeyFromHex(str string) (*PrivateKey, error) {
b, err := hex.DecodeString(str)
if err != nil {
return nil, err
}
return NewPrivateKeyFromBytes(b)
}
// NewPrivateKeyFromBytes returns a NEO PrivateKey from the given byte slice.
func NewPrivateKeyFromBytes(b []byte) (*PrivateKey, error) {
if len(b) != 32 {
return nil, fmt.Errorf(
"invalid byte length: expected %d bytes got %d", 32, len(b),
)
}
return &PrivateKey{b}, nil
}
// PublicKey returns a the public corresponding to the private key
// For the curve secp256r1
func (p *PrivateKey) PublicKey() (*publickey.PublicKey, error) {
var (
c = elliptic.NewEllipticCurve(elliptic.Secp256r1)
q = new(big.Int).SetBytes(p.b)
)
p1, p2 := c.ScalarBaseMult(q.Bytes())
point := elliptic.Point{
X: p1,
Y: p2,
}
if !c.IsOnCurve(p1, p2) {
return nil, errors.New("failed to derive public key using elliptic curve")
}
return &publickey.PublicKey{
Curve: c,
Point: point,
}, nil
}
// WIFEncode will converts a private key
// to the Wallet Import Format for NEO
func WIFEncode(key []byte) (s string) {
if len(key) != 32 {
return "invalid private key length"
}
buf := new(bytes.Buffer)
buf.WriteByte(0x80)
buf.Write(key)
buf.WriteByte(0x01)
checksum, _ := hash.Checksum(buf.Bytes())
buf.Write(checksum)
WIF := base58.Encode(buf.Bytes())
return WIF
}
// Sign will sign the corresponding data using the private key
func (p *PrivateKey) Sign(data []byte) ([]byte, error) {
curve := elliptic.NewEllipticCurve(elliptic.Secp256r1)
key := p.b
digest, _ := hash.Sha256(data)
r, s, err := rfc6979.SignECDSA(curve, key, digest[:], sha256.New)
if err != nil {
return nil, err
}
curveOrderByteSize := curve.P.BitLen() / 8
rBytes, sBytes := r.Bytes(), s.Bytes()
signature := make([]byte, curveOrderByteSize*2)
copy(signature[curveOrderByteSize-len(rBytes):], rBytes)
copy(signature[curveOrderByteSize*2-len(sBytes):], sBytes)
return signature, nil
}