github.com/linapex/ethereum-dpos-chinese@v0.0.0-20190316121959-b78b3a4a1ece/accounts/keystore/key.go

//<developer>
//    <name>linapex 曹一峰</name>
//    <email>linapex@163.com</email>
//    <wx>superexc</wx>
//    <qqgroup>128148617</qqgroup>
//    <url>https://jsq.ink</url>
//    <role>pku engineer</role>
//    <date>2019-03-16 12:09:26</date>
//</624342585040703488>


package keystore

import (
	"bytes"
	"crypto/ecdsa"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"
	"time"

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

const (
	version = 3
)

type Key struct {
Id uuid.UUID //唯一ID的版本4“随机”不是从密钥数据派生的
//为了简化查找，我们还存储了地址
	Address common.Address
//我们只存储privkey，因为pubkey/地址可以从中派生
//此结构中的privkey始终为纯文本
	PrivateKey *ecdsa.PrivateKey
}

type keyStore interface {
//从磁盘加载和解密密钥。
	GetKey(addr common.Address, filename string, auth string) (*Key, error)
//写入并加密密钥。
	StoreKey(filename string, k *Key, auth string) error
//
	JoinPath(filename string) string
}

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 `json:"crypto"`
	Id      string     `json:"id"`
	Version int        `json:"version"`
}

type encryptedKeyJSONV1 struct {
	Address string     `json:"address"`
	Crypto  cryptoJSON `json:"crypto"`
	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"`
}

func (k *Key) MarshalJSON() (j []byte, err error) {
	jStruct := plainKeyJSON{
		hex.EncodeToString(k.Address[:]),
		hex.EncodeToString(crypto.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 := crypto.HexToECDSA(keyJSON.PrivateKey)
	if err != nil {
		return err
	}

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

	return nil
}

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

//newkeywordirecticap生成一个地址小于155位的密钥，以便它可以
//为了简化和更容易与其他libs兼容，我们在直接的icap规范中
//重试，直到第一个字节为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(crypto.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
}

func newKey(rand io.Reader) (*Key, error) {
	privateKeyECDSA, err := ecdsa.GenerateKey(crypto.S256(), rand)
	if err != nil {
		return nil, err
	}
	return newKeyFromECDSA(privateKeyECDSA), nil
}

func storeNewKey(ks keyStore, rand io.Reader, auth string) (*Key, accounts.Account, error) {
	key, err := newKey(rand)
	if err != nil {
		return nil, accounts.Account{}, err
	}
	a := accounts.Account{Address: key.Address, URL: accounts.URL{Scheme: KeyStoreScheme, Path: ks.JoinPath(keyFileName(key.Address))}}
	if err := ks.StoreKey(a.URL.Path, key, auth); err != nil {
		zeroKey(key.PrivateKey)
		return nil, a, err
	}
	return key, a, err
}

func writeKeyFile(file string, content []byte) error {
//使用适当的权限创建keystore目录
//以防它还没有出现。
	const dirPerm = 0700
	if err := os.MkdirAll(filepath.Dir(file), dirPerm); err != nil {
		return err
	}
//原子写入：首先创建临时隐藏文件
//然后移动到位。tempfile指定模式0600。
	f, err := ioutil.TempFile(filepath.Dir(file), "."+filepath.Base(file)+".tmp")
	if err != nil {
		return err
	}
	if _, err := f.Write(content); err != nil {
		f.Close()
		os.Remove(f.Name())
		return err
	}
	f.Close()
	return os.Rename(f.Name(), file)
}

//keyfilename实现了keyfiles的命名约定：
//UTC——<created_at UTC iso8601>-<address hex>
func keyFileName(keyAddr common.Address) string {
	ts := time.Now().UTC()
	return fmt.Sprintf("UTC--%s--%s", toISO8601(ts), hex.EncodeToString(keyAddr[:]))
}

func toISO8601(t time.Time) string {
	var tz string
	name, offset := t.Zone()
	if name == "UTC" {
		tz = "Z"
	} else {
		tz = fmt.Sprintf("%03d00", offset/3600)
	}
	return fmt.Sprintf("%04d-%02d-%02dT%02d-%02d-%02d.%09d%s", t.Year(), t.Month(), t.Day(), t.Hour(), t.Minute(), t.Second(), t.Nanosecond(), tz)
}