path: root/crypto/key.go

// Copyright 2014 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 crypto

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

    "github.com/ethereum/go-ethereum/common"
    "github.com/pborman/uuid"
)

const (
    version = 3
)

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 {
    Address    string `json:"address"`
    PrivateKey string `json:"privatekey"`
    Id         string `json:"id"`
    Version    int    `json:"version"`
}

type encryptedKeyJSONV3 struct {
    Address string `json:"address"`
    Crypto  cryptoJSON
    Id      string `json:"id"`
    Version int    `json:"version"`
}

type encryptedKeyJSONV1 struct {
    Address string `json:"address"`
    Crypto  cryptoJSON
    Id      string `json:"id"`
    Version string `json:"version"`
}

type cryptoJSON struct {
    Cipher       string                 `json:"cipher"`
    CipherText   string                 `json:"ciphertext"`
    CipherParams cipherparamsJSON       `json:"cipherparams"`
    KDF          string                 `json:"kdf"`
    KDFParams    map[string]interface{} `json:"kdfparams"`
    MAC          string                 `json:"mac"`
}

type cipherparamsJSON struct {
    IV string `json:"iv"`
}

type scryptParamsJSON struct {
    N     int    `json:"n"`
    R     int    `json:"r"`
    P     int    `json:"p"`
    DkLen int    `json:"dklen"`
    Salt  string `json:"salt"`
}

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

// generate key whose address fits into < 155 bits so it can fit into
// the Direct ICAP spec. for simplicity and easier compatibility with
// other libs, we retry until the first byte is 0.
func NewKeyForDirectICAP(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())
    }
    key := NewKeyFromECDSA(privateKeyECDSA)
    if !strings.HasPrefix(key.Address.Hex(), "0x00") {
        return NewKeyForDirectICAP(rand)
    }
    return key
}