neoneo-go/pkg/crypto/publickey/publickey.go

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2019-02-25 22:44:14 +00:00
package publickey
import (
"bytes"
"crypto/ecdsa"
"encoding/binary"
"encoding/hex"
"fmt"
"io"
"math/big"
"github.com/CityOfZion/neo-go/pkg/crypto/base58"
"github.com/CityOfZion/neo-go/pkg/crypto/elliptic"
"github.com/CityOfZion/neo-go/pkg/crypto/hash"
)
// PublicKeys is a list of public keys.
type PublicKeys []*PublicKey
func (keys PublicKeys) Len() int { return len(keys) }
func (keys PublicKeys) Swap(i, j int) { keys[i], keys[j] = keys[j], keys[i] }
func (keys PublicKeys) Less(i, j int) bool {
if keys[i].X.Cmp(keys[j].X) == -1 {
return true
}
if keys[i].X.Cmp(keys[j].X) == 1 {
return false
}
if keys[i].X.Cmp(keys[j].X) == 0 {
return false
}
return keys[i].Y.Cmp(keys[j].Y) == -1
}
// PublicKey represents a public key and provides a high level
// API around the ECPoint.
type PublicKey struct {
Curve elliptic.Curve
elliptic.Point
}
// NewPublicKeyFromString return a public key created from the
// given hex string.
func NewPublicKeyFromString(s string) (*PublicKey, error) {
b, err := hex.DecodeString(s)
if err != nil {
return nil, err
}
curve := elliptic.NewEllipticCurve(elliptic.Secp256r1)
pubKey := &PublicKey{curve, elliptic.Point{}}
if err := pubKey.DecodeBinary(bytes.NewReader(b)); err != nil {
return nil, err
}
return pubKey, nil
}
// Bytes returns the byte array representation of the public key.
func (p *PublicKey) Bytes() []byte {
if p.Curve.IsInfinity(p.Point) {
return []byte{0x00}
}
var (
x = p.X.Bytes()
paddedX = append(bytes.Repeat([]byte{0x00}, 32-len(x)), x...)
prefix = byte(0x03)
)
if p.Y.Bit(0) == 0 {
prefix = byte(0x02)
}
return append([]byte{prefix}, paddedX...)
}
// ToAddress will convert a public key to it's neo-address
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func (p *PublicKey) ToAddress() string {
publicKeyBytes := p.Bytes()
publicKeyBytes = append([]byte{0x21}, publicKeyBytes...) // 0x21 = length of pubKey
publicKeyBytes = append(publicKeyBytes, 0xAC) // 0xAC = CheckSig
hash160PubKey, _ := hash.Hash160(publicKeyBytes)
versionHash160PubKey := append([]byte{0x17}, hash160PubKey.Bytes()...)
checksum, _ := hash.Checksum(versionHash160PubKey)
checkVersionHash160 := append(versionHash160PubKey, checksum...)
address := base58.Encode(checkVersionHash160)
return address
}
// DecodeBinary decodes a PublicKey from the given io.Reader.
func (p *PublicKey) DecodeBinary(r io.Reader) error {
var prefix uint8
if err := binary.Read(r, binary.LittleEndian, &prefix); err != nil {
return err
}
// Infinity
if prefix == 0x00 {
p.Point = elliptic.Point{}
return nil
}
// Compressed public keys.
if prefix == 0x02 || prefix == 0x03 {
b := make([]byte, 32)
if err := binary.Read(r, binary.LittleEndian, b); err != nil {
return err
}
var err error
p.Point, err = p.Curve.Decompress(new(big.Int).SetBytes(b), uint(prefix&0x1))
if err != nil {
return err
}
} else if prefix == 0x04 {
buf := make([]byte, 65)
if err := binary.Read(r, binary.LittleEndian, buf); err != nil {
return err
}
p.X = new(big.Int).SetBytes(buf[1:33])
p.Y = new(big.Int).SetBytes(buf[33:65])
} else {
return fmt.Errorf("invalid prefix %d", prefix)
}
return nil
}
// EncodeBinary encodes a PublicKey to the given io.Writer.
func (p *PublicKey) EncodeBinary(w io.Writer) error {
return binary.Write(w, binary.LittleEndian, p.Bytes())
}
// Verify returns true if the signature is valid and corresponds
// to the hash and public key
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func (p *PublicKey) Verify(signature []byte, hash []byte) bool {
publicKey := &ecdsa.PublicKey{}
publicKey.Curve = p.Curve
publicKey.X = p.X
publicKey.Y = p.Y
if p.X == nil || p.Y == nil {
return false
}
rBytes := new(big.Int).SetBytes(signature[0:32])
sBytes := new(big.Int).SetBytes(signature[32:64])
return ecdsa.Verify(publicKey, hash, rBytes, sBytes)
}