从 Java 转换为 C# - 使用 PKCS5Padding 解密 CBC-AES-256

Question

我正在尝试从 ClickBank 解密“即时通知”，他们有用于解码多种语言但没有 C# 的代码示例，因此我正在尝试翻译 Java 代码： https://support.clickbank.com/hc/en-us/articles/220376507-Instant-Notification-Service-INS-#Code%20Samples

过去几天我尝试了几种不同的方法，但都没有成功！请帮忙，我错过了什么？

Java：

final StringBuilder buffer = new StringBuilder();
final String secretKey = "YOUR SECRET KEY";


String line;
final BufferedReader reader = theRequest.getReader();
while(null != (line = reader.readLine())) {
   buffer.append(line);
}


   final JSONParser parser = new JSONParser();
   final JSONObject obj = (JSONObject) parser.parse(buffer.toString()); 

   final String initializationVector = (String) obj.get("iv");
   final String encryptedNotification = (String) obj.get("notification"); 
   final MessageDigest digest = MessageDigest.getInstance("SHA-1");
   digest.reset();
   digest.update(secretKey.getBytes("UTF-8"));
   final String key = new String(Hex.encodeHex(digest.digest())).substring(0, 32);


   final IvParameterSpec iv = new IvParameterSpec(DatatypeConverter.parseBase64Binary(initializationVector));
   final SecretKeySpec keySpec = new SecretKeySpec(key.getBytes(), "AES");
   final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
   cipher.init(Cipher.DECRYPT_MODE, keySpec, iv);

   final JSONObject notification = (JSONObject) parser.parse(
   new String(cipher.doFinal(DatatypeConverter.parseBase64Binary(encryptedNotification)),
                 "ISO-8859-1"));`

C#

        const string secretKey = "YOUR SECRET KEY";
        string sContent = "";
        using (System.IO.Stream receiveStream = Request.InputStream)
        {
            receiveStream.Position = 0;
            using (System.IO.StreamReader readStream =
                   new System.IO.StreamReader(receiveStream, Encoding.UTF8))
            {
                sContent = readStream.ReadToEnd();
            }
        }
        dynamic json = System.Web.Helpers.Json.Decode(sContent);
        string initializationVector = json.iv;
        string encryptedNotification = json.notification;

        //turn the key into a fixed length string via SHA-1 hash
        SHA1 sha1 = SHA1Managed.Create();
        byte[] hash = sha1.ComputeHash(Encoding.UTF8.GetBytes(secretKey));
        var key = Org.BouncyCastle.Utilities.Encoders.Hex.Encode(hash);
        var keyString = Convert.ToBase64String(key).Substring(0, 32);
        //var key = BitConverter.ToString(hash).Substring(0, 32);

        var iv = Convert.FromBase64String(initializationVector);
        byte[] keyspec = Encoding.UTF8.GetBytes(keyString);

         using (var rijndaelManaged =
               new RijndaelManaged { Key = keyspec, IV = iv, Mode = CipherMode.CBC, Padding = PaddingMode.PKCS7 })
        using (var memoryStream =
               new MemoryStream(Convert.FromBase64String(encryptedNotification)))
        using (var cryptoStream =
               new CryptoStream(memoryStream,
                   rijndaelManaged.CreateDecryptor(keyspec, iv),
                   CryptoStreamMode.Read))
        {
            var result = new StreamReader(cryptoStream).ReadToEnd();
        }

给出错误 - '填充无效，无法删除。'

所以我猜我一定是创建了错误的密钥，我尝试了不同的散列和十六进制编码方式，但似乎都不起作用。请各位大侠指教！感谢您的宝贵时间

编辑：删除无用的额外代码

Answer 1

天哪，一家使用 CBC 发送消息的银行。这个 Java 代码示例看起来像是“我第一次尝试加密”，并且来自一家银行，这不是你应该信任的银行。

key确实错了，你应该试试key = Hex.ToHexString()，然后用Encoding.ASCII.GetBytes(key)把结果的子串转成ASCII码。 Java 代码中不存在额外的 base 64 或位转换，因此不应使用。