加密/解密字符串 Kotlin

Question

我在 Kotlin 中创建了这两个扩展来加密/解密字符串：

fun String.encrypt(seed : String): String {
    val keyGenerator = KeyGenerator.getInstance("AES")
    val secureRandom = SecureRandom.getInstance("SHA1PRNG")
    secureRandom.setSeed(seed.toByteArray())

    keyGenerator.init(128, secureRandom)
    val skey = keyGenerator.generateKey()
    val rawKey : ByteArray = skey.encoded

    val skeySpec = SecretKeySpec(rawKey, "AES")
    val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
    cipher.init(Cipher.ENCRYPT_MODE, skeySpec)
    val byteArray = cipher.doFinal(this.toByteArray())

    return byteArray.toString()
}

fun String.decrypt(seed : String): String {
    val keyGenerator = KeyGenerator.getInstance("AES")
    val secureRandom = SecureRandom.getInstance("SHA1PRNG")
    secureRandom.setSeed(seed.toByteArray())

    keyGenerator.init(128, secureRandom)
    val skey = keyGenerator.generateKey()
    val rawKey : ByteArray = skey.encoded

    val skeySpec = SecretKeySpec(rawKey, "AES")
    val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
    cipher.init(Cipher.DECRYPT_MODE, skeySpec)
    val byteArray = cipher.doFinal(this.toByteArray())

    return byteArray.toString()
}

出于某种原因，我收到以下异常：

javax.crypto.IllegalBlockSizeException: last block incomplete in decryption

我做错了什么？

Answer 1

AES 加密/解密使用 base64 密钥、salt 和 iv（初始化向量）。

object AESEncyption {

const val secretKey = "tK5UTui+DPh8lIlBxya5XVsmeDCoUl6vHhdIESMB6sQ="
const val salt = "QWlGNHNhMTJTQWZ2bGhpV3U=" // base64 decode => AiF4sa12SAfvlhiWu
const val iv = "bVQzNFNhRkQ1Njc4UUFaWA==" // base64 decode => mT34SaFD5678QAZX

fun encrypt(strToEncrypt: String) :  String?
{
    try
    {
        val ivParameterSpec = IvParameterSpec(Base64.decode(iv, Base64.DEFAULT))

        val factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1")
        val spec =  PBEKeySpec(secretKey.toCharArray(), Base64.decode(salt, Base64.DEFAULT), 10000, 256)
        val tmp = factory.generateSecret(spec)
        val secretKey =  SecretKeySpec(tmp.encoded, "AES")

        val cipher = Cipher.getInstance("AES/CBC/PKCS7Padding")
        cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivParameterSpec)
        return Base64.encodeToString(cipher.doFinal(strToEncrypt.toByteArray(Charsets.UTF_8)), Base64.DEFAULT)
    }
    catch (e: Exception)
    {
        println("Error while encrypting: $e")
    }
    return null
}

fun decrypt(strToDecrypt : String) : String? {
    try
    {

        val ivParameterSpec =  IvParameterSpec(Base64.decode(iv, Base64.DEFAULT))

        val factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1")
        val spec =  PBEKeySpec(secretKey.toCharArray(), Base64.decode(salt, Base64.DEFAULT), 10000, 256)
        val tmp = factory.generateSecret(spec);
        val secretKey =  SecretKeySpec(tmp.encoded, "AES")

        val cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
        cipher.init(Cipher.DECRYPT_MODE, secretKey, ivParameterSpec);
        return  String(cipher.doFinal(Base64.decode(strToDecrypt, Base64.DEFAULT)))
    }
    catch (e : Exception) {
        println("Error while decrypting: $e");
    }
    return null
  }
}

iOS迅捷

Answer 2

按照 Maarten Bodews 指南，我将问题解决为：

fun String.encrypt(password: String): String {
    val secretKeySpec = SecretKeySpec(password.toByteArray(), "AES")
    val iv = ByteArray(16)
    val charArray = password.toCharArray()
    for (i in 0 until charArray.size){
        iv[i] = charArray[i].toByte()
    }
    val ivParameterSpec = IvParameterSpec(iv)

    val cipher = Cipher.getInstance("AES/GCM/NoPadding")
    cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec)

    val encryptedValue = cipher.doFinal(this.toByteArray())
    return Base64.encodeToString(encryptedValue, Base64.DEFAULT)
}

fun String.decrypt(password: String): String {
    val secretKeySpec = SecretKeySpec(password.toByteArray(), "AES")
    val iv = ByteArray(16)
    val charArray = password.toCharArray()
    for (i in 0 until charArray.size){
        iv[i] = charArray[i].toByte()
    }
    val ivParameterSpec = IvParameterSpec(iv)

    val cipher = Cipher.getInstance("AES/GCM/NoPadding")
    cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec)

    val decryptedByteValue = cipher.doFinal(Base64.decode(this, Base64.DEFAULT))
    return String(decryptedByteValue)
}

Answer 3

要对您的密文进行编码，请使用 base 64 或十六进制。Java API 包含一个 Base64 类，因此您最好使用它。

byte[]#toString没有做你期望它做的事情；它只是返回字节数组引用的表示，而不是字节数组的内容。

除此之外：

• 不要使用 SecureRandom 来派生密钥，尝试查找 PBKDF2；
• 明确使用操作模式，例如"AES/GCM/NoPadding"；
• 如果您决定使用 CBC（通常不安全），请使用唯一的 IV 和随机的 IV；
• 不要在没有toByteArray为消息明确选择字符编码的情况下使用。