抛出BadpaddingException但在.NET中工作的Java解码逻辑

Question

         byte[]   toEncryptArray = Convert.FromBase64String(encryptedString)
         MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
         byte[]  keyArray = hashmd5.ComputeHash(System.Text.Encoding.Unicode.GetBytes(key));              
            hashmd5.Clear(); 
        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
        tdes.Key = keyArray;
        tdes.Mode = CipherMode.ECB;
        tdes.Padding = PaddingMode.PKCS7; 
        ICryptoTransform cTransform = tdes.CreateDecryptor();
        byte[] resultArray = cTransform.TransformFinalBlock(
                             toEncryptArray, 0, toEncryptArray.Length);

    }

    byte[] message = Base64.decodeBase64(encryptedText.getBytes("UTF-8"));
        MessageDigest md = MessageDigest.getInstance("MD5");
        byte[] digestOfUsername = md.digest(key.getBytes("UTF-8"));
        byte[] keyBytes = Arrays.copyOf(digestOfUsername, 24);
        SecretKey key = new SecretKeySpec(keyBytes, "DESede");
Cipher decipher = Cipher.getInstance("DESede/ECB/PKCS5Padding",new SunJCE());
        decipher.init(Cipher.DECRYPT_MODE, key);
        byte[] plainText = decipher.doFinal(message);// BadpaddingException 
        String decryptedString = new String(plainText);

.NET代码工作良好，但java是代码没有给出正确的输出，它给出了BadpaddingException：at dofinal()，请纠正我做错的地方。

Answer 1

好的，所以问题是您正在将加密的字节转换为十六进制字符串（使用asHex方法），但没有将十六进制字符串正确地转换回字节数组以进行解密。不能使用GetBytes。

可以使用以下方法将十六进制字符串转换为字节数组：

public static byte[] fromHexString(String s) {
    int len = s.length();
    byte[] data = new byte[len / 2];
    for (int i = 0; i < len; i += 2) {
        data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
                             + Character.digit(s.charAt(i+1), 16));
    }
    return data;
}

然后将解密方法更改为：

original = decipher.doFinal(fromHexString(message));