89 lines
3.2 KiB
Go
89 lines
3.2 KiB
Go
// Copyright 2017 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/>.
|
|
|
|
//go:build !nacl && !js && cgo && !gofuzz
|
|
// +build !nacl,!js,cgo,!gofuzz
|
|
|
|
package crypto
|
|
|
|
import (
|
|
"crypto/ecdsa"
|
|
"crypto/elliptic"
|
|
"fmt"
|
|
|
|
"github.com/ethereum/go-ethereum/common/math"
|
|
"github.com/ethereum/go-ethereum/crypto/secp256k1"
|
|
)
|
|
|
|
// Ecrecover returns the uncompressed public key that created the given signature.
|
|
func Ecrecover(hash, sig []byte) ([]byte, error) {
|
|
return secp256k1.RecoverPubkey(hash, sig)
|
|
}
|
|
|
|
// SigToPub returns the public key that created the given signature.
|
|
func SigToPub(hash, sig []byte) (*ecdsa.PublicKey, error) {
|
|
s, err := Ecrecover(hash, sig)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
x, y := elliptic.Unmarshal(S256(), s)
|
|
return &ecdsa.PublicKey{Curve: S256(), X: x, Y: y}, nil
|
|
}
|
|
|
|
// 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 digest cannot be chosen by an adversary. 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(digestHash []byte, prv *ecdsa.PrivateKey) (sig []byte, err error) {
|
|
if len(digestHash) != DigestLength {
|
|
return nil, fmt.Errorf("hash is required to be exactly %d bytes (%d)", DigestLength, len(digestHash))
|
|
}
|
|
seckey := math.PaddedBigBytes(prv.D, prv.Params().BitSize/8)
|
|
defer zeroBytes(seckey)
|
|
return secp256k1.Sign(digestHash, seckey)
|
|
}
|
|
|
|
// VerifySignature checks that the given public key created signature over digest.
|
|
// The public key should be in compressed (33 bytes) or uncompressed (65 bytes) format.
|
|
// The signature should have the 64 byte [R || S] format.
|
|
func VerifySignature(pubkey, digestHash, signature []byte) bool {
|
|
return secp256k1.VerifySignature(pubkey, digestHash, signature)
|
|
}
|
|
|
|
// DecompressPubkey parses a public key in the 33-byte compressed format.
|
|
func DecompressPubkey(pubkey []byte) (*ecdsa.PublicKey, error) {
|
|
x, y := secp256k1.DecompressPubkey(pubkey)
|
|
if x == nil {
|
|
return nil, fmt.Errorf("invalid public key")
|
|
}
|
|
return &ecdsa.PublicKey{X: x, Y: y, Curve: S256()}, nil
|
|
}
|
|
|
|
// CompressPubkey encodes a public key to the 33-byte compressed format.
|
|
func CompressPubkey(pubkey *ecdsa.PublicKey) []byte {
|
|
return secp256k1.CompressPubkey(pubkey.X, pubkey.Y)
|
|
}
|
|
|
|
// S256 returns an instance of the secp256k1 curve.
|
|
func S256() elliptic.Curve {
|
|
return secp256k1.S256()
|
|
}
|