golang 實現 ETH 交易離線簽名（冷籤）

摘要： 構造交易 import ( "github.com/ethereum/go-ethereum/core/types" "github.com/ethereum/go-ethereum/common" "github.com/e...

構造交易

import (
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/common/hexutil"
)
const (
GAS_LIMIT= 21000
GAS_PRICE= 500000000000
)
tx := types.NewTransaction(nonce, common.HexToAddress(toAddress), value, GAS_LIMIT, big.NewInt(GAS_PRICE), nil)

簽名交易

其中StringToPrivateKey 是獲取私鑰的方法，在下邊會有介紹

func SignTransaction(tx *types.Transaction, privateKeyStr string) (string, error) {
privateKey, err := StringToPrivateKey(privateKeyStr)
if err != nil {
return "", err
}
signTx, err := types.SignTx(tx, types.NewEIP155Signer(big.NewInt(4)), privateKey)
//signTx, err := types.SignTx(tx, types.HomesteadSigner{}, privateKey)
if err != nil {
return "", nil
}

b, err := rlp.EncodeToBytes(signTx)
if err != nil {
return "", err
}
return hex.EncodeToString(b), nil
}

其中籤名有兩種演算法

• types.NewEIP155Signer(big.NewInt(chainId))
• types.HomesteadSigner{}

第二種不需要提供chainId 但是據說不穩定，types.NewEIP155Signer(big.NewInt(4) 4 是 rinkeby 測試網路，1是主網

私鑰的獲取 *ecdsa.PrivateKey

1. 從明文的私鑰字串轉換成該型別

func StringToPrivateKey(privateKeyStr string) (*ecdsa.PrivateKey, error) {
privateKeyByte, err := hexutil.Decode(privateKeyStr)
if err != nil {
return nil, err
}
privateKey, err := crypto.ToECDSA(privateKeyByte)
if err != nil {
return nil, err
}
return privateKey, nil
}

2. keystore + password 解析出私鑰

func KeystoreToPrivateKey(keystoreContent []byte, password string) (*ecdsa.PrivateKey, error) {
unlockedKey, err := keystore.DecryptKey(keystoreContent, password)
if err != nil {
return nil, err
}
return unlockedKey.PrivateKey, nil
}