首先,我想说这只是一个学习练习,我不打算在 生产环境 中使用它 .
encrypt(plaintext string, password string)decrypt(encrypted string, password string)
加密步骤是:
-
生成随机256位以用作salt
-
生成128位用作初始化向量
-
使用PDKDF2从密码和salt生成32位密钥
-
使用密钥和明文生成32位HMAC,并将其附加到明文的开头
-
在CFB模式下使用AES加密hmac明文
返回的字节数组如下所示:
[256 bit salt] [128 bit iv] encrypted([256 bit hmac] [plaintext])
解密时:
-
解压缩盐并将其与提供的密码一起使用以计算密钥
-
提取IV并解密密文的加密部分
-
从解密的值中提取mac
-
使用明文验证mac
我没有疯狂到在任何 生产环境 项目中使用我自己的加密脚本,所以请指向我这样做的任何库(简单的密码/消息加密相对安全)
这是两个函数的源代码:
package main
import (
"io"
"crypto/rand"
"crypto/cipher"
"crypto/aes"
"crypto/sha256"
"crypto/hmac"
"golang.org/x/crypto/pbkdf2"
)
const saltlen = 32
const keylen = 32
const iterations = 100002
// returns ciphertext of the following format:
// [32 bit salt][128 bit iv][encrypted plaintext]
func encrypt(plaintext string, password string) string {
// allocate memory to hold the header of the ciphertext
header := make([]byte, saltlen + aes.BlockSize)
// generate salt
salt := header[:saltlen]
if _, err := io.ReadFull(rand.Reader, salt); err != nil {
panic(err)
}
// generate initialization vector
iv := header[saltlen:aes.BlockSize+saltlen]
if _, err := io.ReadFull(rand.Reader, iv); err != nil {
panic(err)
}
// generate a 32 bit key with the provided password
key := pbkdf2.Key([]byte(password), salt, iterations, keylen, sha256.New)
// generate a hmac for the message with the key
mac := hmac.New(sha256.New, key)
mac.Write([]byte(plaintext))
hmac := mac.Sum(nil)
// append this hmac to the plaintext
plaintext = string(hmac) + plaintext
//create the cipher
block, err := aes.NewCipher(key)
if err != nil {
panic(err)
}
// allocate space for the ciphertext and write the header to it
ciphertext := make([]byte, len(header) + len(plaintext))
copy(ciphertext, header)
// encrypt
stream := cipher.NewCFBEncrypter(block, iv)
stream.XORKeyStream(ciphertext[aes.BlockSize+saltlen:], []byte(plaintext))
return string(ciphertext)
}
func decrypt(encrypted string, password string) string {
ciphertext := []byte(encrypted)
// get the salt from the ciphertext
salt := ciphertext[:saltlen]
// get the IV from the ciphertext
iv := ciphertext[saltlen:aes.BlockSize+saltlen]
// generate the key with the KDF
key := pbkdf2.Key([]byte(password), salt, iterations, keylen, sha256.New)
block, err := aes.NewCipher(key)
if (err != nil) {
panic(err)
}
if len(ciphertext) < aes.BlockSize {
return ""
}
decrypted := ciphertext[saltlen+aes.BlockSize:]
stream := cipher.NewCFBDecrypter(block, iv)
stream.XORKeyStream(decrypted, decrypted)
// extract hmac from plaintext
extractedMac := decrypted[:32]
plaintext := decrypted[32:]
// validate the hmac
mac := hmac.New(sha256.New, key)
mac.Write(plaintext)
expectedMac := mac.Sum(nil)
if !hmac.Equal(extractedMac, expectedMac) {
return ""
}
return string(plaintext)
}