path: root/accounts/abi/bind/auth.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/>.

package bind

import (
    "crypto/ecdsa"
    "errors"
    "io"
    "io/ioutil"

    "github.com/ethereum/go-ethereum/accounts"
    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/crypto"
)

// NewTransactor is a utility method to easily create a transaction signer from
// an encrypted json key stream and the associated passphrase.
func NewTransactor(keyin io.Reader, passphrase string) (*TransactOpts, error) {
    json, err := ioutil.ReadAll(keyin)
    if err != nil {
        return nil, err
    }
    key, err := accounts.DecryptKey(json, passphrase)
    if err != nil {
        return nil, err
    }
    return NewKeyedTransactor(key.PrivateKey), nil
}

// NewKeyedTransactor is a utility method to easily create a transaction signer
// from a single private key.
func NewKeyedTransactor(key *ecdsa.PrivateKey) *TransactOpts {
    keyAddr := crypto.PubkeyToAddress(key.PublicKey)
    return &TransactOpts{
        From: keyAddr,
        Signer: func(address common.Address, tx *types.Transaction) (*types.Transaction, error) {
            if address != keyAddr {
                return nil, errors.New("not authorized to sign this account")
            }
            signature, err := crypto.Sign(tx.SigHash().Bytes(), key)
            if err != nil {
                return nil, err
            }
            return tx.WithSignature(signature)
        },
    }
}