AES (rijndael) decryption

我有一个安全类，可以编码和解码字符串，但是当我尝试解码时 - 出了点问题。

这是我的安全类：

class Security
{
    public static String encrypt(String imput, String key)
    {
        String cipherText;
        var rijndael = new RijndaelManaged()
        {
            Key = Encoding.Unicode.GetBytes(key),
            Mode = CipherMode.ECB,
            BlockSize = 128,
            Padding = PaddingMode.Zeros,
        };
        ICryptoTransform encryptor = rijndael.CreateEncryptor(rijndael.Key, null);
        using (var memoryStream = new MemoryStream())
        {
            using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
            {
                using (var streamWriter = new StreamWriter(cryptoStream))
                {
                    streamWriter.Write(imput);
                    streamWriter.Flush();
                }
                cipherText = Convert.ToBase64String(memoryStream.ToArray());
            }
        }
        return cipherText;
    }
    public static String decrypt(String imput, String key)
    {
        byte[] data = Convert.FromBase64String(imput);
        String decrypted;
        using (RijndaelManaged rijAlg = new RijndaelManaged())
        {
            rijAlg.Key = Encoding.UTF8.GetBytes(key);
            rijAlg.Mode = CipherMode.ECB;
            rijAlg.BlockSize = 128;
            rijAlg.Padding = PaddingMode.Zeros;
            ICryptoTransform decryptor = rijAlg.CreateDecryptor(rijAlg.Key, null);
            using (MemoryStream msDecrypt = new MemoryStream(data))
            {
                using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                {
                    using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                    {
                        decrypted = srDecrypt.ReadToEnd();                            
                    }
                }
            }
        }
        return decrypted;
    }
}

在程序中.cs：

String A = Security.encrypt("text", "1234567891234567");
A = Security.decrypt(A, "1234567891234567");

最后它返回类似的东西：% ;''0 ''a f6 ，但我需要原始字符串。我哪里犯了错误？