Encrypt with Java and decrypt with C #

Code that encrypts with Java to build a mechanism that decrypts the character string encrypted on the Java side for authentication of Android running on Java and API server running on .NET and performs authentication processing on the .Net side , I made a code to decrypt with C #.


    @RequiresApi(api = Build.VERSION_CODES.O)
    public static String Encrypt(String text, String key)
            throws Exception {
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        byte[] keyBytes= new byte[16];
        byte[] b= key.getBytes(StandardCharsets.UTF_8);
        int len= b.length;
        if (len > keyBytes.length) len = keyBytes.length;
        System.arraycopy(b, 0, keyBytes, 0, len);
        SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");
        IvParameterSpec ivSpec = new IvParameterSpec(keyBytes);

        byte[] results = cipher.doFinal(text.getBytes(StandardCharsets.UTF_8));
        String result = Base64.getEncoder().encodeToString(results);
        return result;


       public static string Decrypt(string textToDecrypt, string key)
            System.Text.UTF8Encoding encoding = new System.Text.UTF8Encoding();

            RijndaelManaged rijndaelCipher = new RijndaelManaged();
            rijndaelCipher.Mode = CipherMode.CBC;
            rijndaelCipher.Padding = PaddingMode.PKCS7;

            rijndaelCipher.KeySize = 0x80;
            rijndaelCipher.BlockSize = 0x80;

            //string decodedUrl = HttpUtility.UrlDecode(textToDecrypt);
            byte[] encryptedData = Convert.FromBase64String(textToDecrypt);
            byte[] pwdBytes = Encoding.UTF8.GetBytes(key);
            byte[] keyBytes = new byte[0x10];
            int len = pwdBytes.Length;
            if (len > keyBytes.Length)
                len = keyBytes.Length;
            Array.Copy(pwdBytes, keyBytes, len);
            rijndaelCipher.Key = keyBytes;
            rijndaelCipher.IV = keyBytes;
            byte[] plainText = rijndaelCipher.CreateDecryptor().TransformFinalBlock(encryptedData, 0, encryptedData.Length);
            return encoding.GetString(plainText);

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