forked from cerc-io/plugeth
78 lines
2.4 KiB
Go
78 lines
2.4 KiB
Go
|
// Copyright 2016 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/>.
|
||
|
|
|
||
|
|
// +build nacl js nocgo
|
||
|
|
|
||
|
|
package crypto
|
||
|
|
|
||
|
|
import (
|
||
|
|
"crypto/ecdsa"
|
||
|
|
"crypto/elliptic"
|
||
|
|
"fmt"
|
||
|
|
|
||
|
|
"github.com/btcsuite/btcd/btcec"
|
||
|
|
)
|
||
|
|
|
||
|
|
func Ecrecover(hash, sig []byte) ([]byte, error) {
|
||
|
|
pub, err := SigToPub(hash, sig)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
bytes := (*btcec.PublicKey)(pub).SerializeUncompressed()
|
||
|
|
return bytes, err
|
||
|
|
}
|
||
|
|
|
||
|
|
func SigToPub(hash, sig []byte) (*ecdsa.PublicKey, error) {
|
||
|
|
// Convert to btcec input format with 'recovery id' v at the beginning.
|
||
|
|
btcsig := make([]byte, 65)
|
||
|
|
btcsig[0] = sig[64] + 27
|
||
|
|
copy(btcsig[1:], sig)
|
||
|
|
|
||
|
|
pub, _, err := btcec.RecoverCompact(btcec.S256(), btcsig, hash)
|
||
|
|
return (*ecdsa.PublicKey)(pub), err
|
||
|
|
}
|
||
|
|
|
||
|
|
// Sign calculates an ECDSA signature.
|
||
|
|
//
|
||
|
|
// This function is susceptible to chosen plaintext attacks that can leak
|
||
|
|
// information about the private key that is used for signing. Callers must
|
||
|
|
// be aware that the given hash cannot be chosen by an adversery. Common
|
||
|
|
// solution is to hash any input before calculating the signature.
|
||
|
|
//
|
||
|
|
// The produced signature is in the [R || S || V] format where V is 0 or 1.
|
||
|
|
func Sign(hash []byte, prv *ecdsa.PrivateKey) ([]byte, error) {
|
||
|
|
if len(hash) != 32 {
|
||
|
|
return nil, fmt.Errorf("hash is required to be exactly 32 bytes (%d)", len(hash))
|
||
|
|
}
|
||
|
|
if prv.Curve != btcec.S256() {
|
||
|
|
return nil, fmt.Errorf("private key curve is not secp256k1")
|
||
|
|
}
|
||
|
|
sig, err := btcec.SignCompact(btcec.S256(), (*btcec.PrivateKey)(prv), hash, false)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
// Convert to Ethereum signature format with 'recovery id' v at the end.
|
||
|
|
v := sig[0] - 27
|
||
|
|
copy(sig, sig[1:])
|
||
|
|
sig[64] = v
|
||
|
|
return sig, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// S256 returns an instance of the secp256k1 curve.
|
||
|
|
func S256() elliptic.Curve {
|
||
|
|
return btcec.S256()
|
||
|
|
}
|