public class Crypt
    {
        string key = null;
        RijndaelManaged rijndaelCipher = null;

        public Crypt(string key) 
        {
            this.key = key;
            rijndaelCipher = new RijndaelManaged();
            rijndaelCipher.Mode = CipherMode.CBC;
            rijndaelCipher.Padding = PaddingMode.PKCS7;
            rijndaelCipher.KeySize = 0x80;
            rijndaelCipher.BlockSize = 0x80;
        }

        public byte[] Decrypt(byte[] data)
        {
            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;
            return rijndaelCipher.CreateDecryptor().TransformFinalBlock(data, 0, data.Length);
        }

        public byte[] Encrypt(byte[] data)
        {
            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;
            ICryptoTransform transform = rijndaelCipher.CreateEncryptor();
            byte[] plainText = data;
            return transform.TransformFinalBlock(plainText, 0, plainText.Length);
        }

    }