path: root/crypto/key.go

/*
    This file is part of go-ethereum

    go-ethereum 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.

    go-ethereum 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 General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with go-ethereum.  If not, see <http://www.gnu.org/licenses/>.
*/
/**
 * @authors
 *  Gustav Simonsson <gustav.simonsson@gmail.com>
 * @date 2015
 *
 */

package crypto

import (
    "bytes"
    "crypto/ecdsa"
    "encoding/hex"
    "encoding/json"
    "io"

    "code.google.com/p/go-uuid/uuid"
    "github.com/ethereum/go-ethereum/common"
)

const (
    version = "1"
)

type Key struct {
    Id uuid.UUID // Version 4 "random" for unique id not derived from key data
    // to simplify lookups we also store the address
    Address common.Address
    // we only store privkey as pubkey/address can be derived from it
    // privkey in this struct is always in plaintext
    PrivateKey *ecdsa.PrivateKey
}

type plainKeyJSON struct {
    Version    string
    Id         string
    Address    string
    PrivateKey string
}

type encryptedKeyJSON struct {
    Version string
    Id      string
    Address string
    Crypto  cipherJSON
}

type cipherJSON struct {
    MAC        string
    Salt       string
    IV         string
    KeyHeader  keyHeaderJSON
    CipherText string
}

type keyHeaderJSON struct {
    Version   string
    Kdf       string
    KdfParams scryptParamsJSON
}

type scryptParamsJSON struct {
    N       int
    R       int
    P       int
    DkLen   int
    SaltLen int
}

func (k *Key) MarshalJSON() (j []byte, err error) {
    jStruct := plainKeyJSON{
        version,
        k.Id.String(),
        hex.EncodeToString(k.Address[:]),
        hex.EncodeToString(FromECDSA(k.PrivateKey)),
    }
    j, err = json.Marshal(jStruct)
    return j, err
}

func (k *Key) UnmarshalJSON(j []byte) (err error) {
    keyJSON := new(plainKeyJSON)
    err = json.Unmarshal(j, &keyJSON)
    if err != nil {
        return err
    }

    u := new(uuid.UUID)
    *u = uuid.Parse(keyJSON.Id)
    k.Id = *u
    addr, err := hex.DecodeString(keyJSON.Address)
    if err != nil {
        return err
    }

    privkey, err := hex.DecodeString(keyJSON.PrivateKey)
    if err != nil {
        return err
    }

    k.Address = common.BytesToAddress(addr)
    k.PrivateKey = ToECDSA(privkey)

    return nil
}

func NewKeyFromECDSA(privateKeyECDSA *ecdsa.PrivateKey) *Key {
    id := uuid.NewRandom()
    key := &Key{
        Id:         id,
        Address:    common.BytesToAddress(PubkeyToAddress(privateKeyECDSA.PublicKey)),
        PrivateKey: privateKeyECDSA,
    }
    return key
}

func NewKey(rand io.Reader) *Key {
    randBytes := make([]byte, 64)
    _, err := rand.Read(randBytes)
    if err != nil {
        panic("key generation: could not read from random source: " + err.Error())
    }
    reader := bytes.NewReader(randBytes)
    privateKeyECDSA, err := ecdsa.GenerateKey(S256(), reader)
    if err != nil {
        panic("key generation: ecdsa.GenerateKey failed: " + err.Error())
    }

    return NewKeyFromECDSA(privateKeyECDSA)
}