65 lines
2.1 KiB
Go
65 lines
2.1 KiB
Go
// Copyright 2017 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// +build !nacl,!js,!nocgo
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package crypto
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import (
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"crypto/ecdsa"
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"crypto/elliptic"
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"fmt"
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"github.com/ethereum/go-ethereum/common/math"
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"github.com/ethereum/go-ethereum/crypto/secp256k1"
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)
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func Ecrecover(hash, sig []byte) ([]byte, error) {
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return secp256k1.RecoverPubkey(hash, sig)
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}
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func SigToPub(hash, sig []byte) (*ecdsa.PublicKey, error) {
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s, err := Ecrecover(hash, sig)
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if err != nil {
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return nil, err
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}
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x, y := elliptic.Unmarshal(S256(), s)
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return &ecdsa.PublicKey{Curve: S256(), X: x, Y: y}, nil
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}
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// Sign calculates an ECDSA signature.
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//
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// This function is susceptible to chosen plaintext attacks that can leak
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// information about the private key that is used for signing. Callers must
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// be aware that the given hash cannot be chosen by an adversery. Common
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// solution is to hash any input before calculating the signature.
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//
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// The produced signature is in the [R || S || V] format where V is 0 or 1.
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func Sign(hash []byte, prv *ecdsa.PrivateKey) (sig []byte, err error) {
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if len(hash) != 32 {
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return nil, fmt.Errorf("hash is required to be exactly 32 bytes (%d)", len(hash))
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}
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seckey := math.PaddedBigBytes(prv.D, prv.Params().BitSize/8)
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defer zeroBytes(seckey)
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return secp256k1.Sign(hash, seckey)
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}
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// S256 returns an instance of the secp256k1 curve.
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func S256() elliptic.Curve {
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return secp256k1.S256()
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}
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