class CCrypt
    {
        public byte[] Crypt(string StrInput, out byte[] ByKey, out byte[] ByIV)
        {
            try
            {
                RijndaelManaged RMRijndal = new RijndaelManaged();
                ASCIIEncoding AEConvert = new ASCIIEncoding();
                byte[] ByEncrypted;
                byte[] ByToEncrypt;
                RMRijndal.GenerateKey();
                RMRijndal.GenerateIV();
                ByKey = RMRijndal.Key;
                ByIV = RMRijndal.IV;
                ICryptoTransform ICTEncryptor = RMRijndal.CreateEncryptor(ByKey, ByIV);
                MemoryStream MsEncrypt = new MemoryStream();
                CryptoStream CsEncrpyt = new CryptoStream(MsEncrypt, ICTEncryptor, CryptoStreamMode.Write);
                ByToEncrypt = AEConvert.GetBytes(StrInput);
                CsEncrpyt.Write(ByToEncrypt, 0, ByToEncrypt.Length);
                CsEncrpyt.FlushFinalBlock();
                ByEncrypted = MsEncrypt.ToArray();
                return ByEncrypted;
            }
            catch (CryptographicException e)
            {
                MessageBox.Show("A Cryptographic error occurred: {0}", e.Message);
                ByKey = null;
                ByIV = null;
                return null;
            }
            
        }

class CDecrypt
    {
        public string Decrypt(byte[] ByInput, byte[] ByKey, byte[] ByIV)
        {
            try
            {
                RijndaelManaged RMRijndal = new RijndaelManaged();
                ASCIIEncoding AEConvert = new ASCIIEncoding();
                byte[] BySource;
                ICryptoTransform ICDecryptor = RMRijndal.CreateDecryptor(ByKey, ByIV);
                MemoryStream MsDecrypt = new MemoryStream(ByInput);
                CryptoStream CsDecrypt = new CryptoStream(MsDecrypt, ICDecryptor, CryptoStreamMode.Read);
                BySource = new byte[ByInput.Length];
                CsDecrypt.Read(BySource, 0, BySource.Length);
                string StrOutput = AEConvert.GetString(BySource);
                return StrOutput;
            }
            catch (CryptographicException e)
            {
                MessageBox.Show("A Cryptographic error occurred: {0}", e.Message);
                return null;
            }
        }

private void BtSave_Click(object sender, EventArgs e)
        {
            byte[] ByKey, ByIV;
            CCrypt crypt = new CCrypt();
            ASCIIEncoding AEEncoding = new ASCIIEncoding();
            CSqlSettings settings = new CSqlSettings();
            String[] AStrSettings = new string[6];
            AStrSettings[0] = TbServername.Text;
            AStrSettings[1] = TbUsername.Text;
            AStrSettings[2] = AEEncoding.GetString(crypt.Crypt(TbPassword.Text, out ByKey, out ByIV));
            AStrSettings[3] = CbDatabase.SelectedItem.ToString();
            AStrSettings[4] = AEEncoding.GetString(ByKey);
            AStrSettings[5] = AEEncoding.GetString(ByIV);
            settings.WriteSetting(AStrSettings);
            BtCancel.Text = "Close";
            BtSave.Enabled = false;
        }

 CsDecrypt.Read(BySource, 0, BySource.Length);

\0

MemoryStream MsDecrypt = new MemoryStream(ByInput);
MsDecrypt.Position = 0;