java - Android 不支持的 key 大小 : 3 bytes on decrypt text

Question

我有简单的 json 对象:

json:

{
  "bookInfo": {
    "type": "book",
    "onvan": "کتاب دو",
    "tadvin": "دفتر",
    "nasher": "بوستان",
    "nobat": "اول",
    "shabek": "1100",
    "gheymat": "2000 تومان",
    "tasvirData": ""
  }
}

在使用 123 key 对 c# 进行加密之后，我得到以下结果:

hlAkzlLeVE3JdYrk61dy8901K2tXWqx5qxYd1t8zVSZzx12lD6nxqZRlPRI8yX8PECxaHJ5zdueY0/A0J7Lxxlv2DHvdI/H+Qu2bsQI6X/Qc6ISwlY7Q6c0IiwWtKuFm5f8BC9wNSSqPXkBM7J+hwEtHUBAoh+IMzxNXvnA/hZIp3R2FznX4cdJhs4Lnm003WLGiKwJ1fEgzUl55WKBIh2dMwQwqpTlNmLFIo6ovlJYMt4DTaoeET+VAhHcGtX1u10910EZ1hCqb1pcspE1SPQ==

现在，当我尝试使用 123 key 解密时，我收到此错误:

Unsupported key size: 3 bytes

EncryptUtils 类:

public class EncryptUtils {
    public static SecretKey generateKey(String mySecret) throws NoSuchAlgorithmException, InvalidKeySpecException {
        return new SecretKeySpec(mySecret.getBytes(), "AES");
    }

    public static byte[] encryptMsg(String message, SecretKey secret)
            throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, InvalidParameterSpecException, IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException {
        Cipher cipher = null;
        cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secret);
        byte[] cipherText = cipher.doFinal(message.getBytes("UTF-8"));
        return cipherText;
    }

    public static String decryptMsg(byte[] cipherText, SecretKey secret)
            throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidParameterSpecException, InvalidAlgorithmParameterException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException, UnsupportedEncodingException {
        Cipher cipher = null;
        cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, secret);
        String decryptString = new String(cipher.doFinal(cipherText), "UTF-8");
        return decryptString;
    }
}

这是我的解密代码:

String mySecret="123";
SecretKey secretKey = EncryptUtils.generateKey(mySecret);
JSONObject bookObject = new JSONObject(EncryptUtils.decryptMsg(bookContent.getBytes("UTF-8"), secretKey));

Answer 1

问题是您传入 hexToBytes 函数的字符串是 Base64 编码的，它不是十六进制字符串，因此将前两个字符读取为整数会导致异常。

将解密中的行更改为:

String decryptString = new String(cipher.doFinal(cipherText), "UTF-8");

致:

String decryptString= cipher.doFinal(Base64.decode(cipherText,Base64.DEFAULT)); 

编码愉快!!