Adddecrypt database users, password design

/// public class securityService {static protected byte [] bytekey = {125, 14, 45, 67, 112, 79, 77, 99, 37, 104, 13, 9, 118, 51, 87, 108 }; static protected Byte [] byteIV = {86, 19, 79, 15, 72, 58, 117, 45}; static public string SymmetricEncrypt (String sPlainText) {Byte [] bytePlaintext; MemoryStream EncryptedStream; ICryptoTransform Encryptor; CryptoStream TheCryptoStream; if (sPlainText == "") return ""; bytePlaintext = Encoding.ASCII.GetBytes (sPlainText); EncryptedStream = new MemoryStream (sPlainText.Length); Encryptor = GetEncryptor (); TheCryptoStream = new CryptoStream (EncryptedStream, Encryptor, CryptoStreamMode. Write); TheCryptoStream.Write (bytePlaintext, 0, bytePlaintext.Length); TheCryptoStream.FlushFinalBlock (); TheCryptoStream.Close (); return Convert.ToBase64String (EncryptedStream.ToArray ());} // End Function static public string SymmetricDecrypt ( String SencryptedText) {byte [] byteencrypted; memorystream plaintextstst ream; ICryptoTransform Decryptor; CryptoStream TheCryptoStream; if (sEncryptedText == "") return ""; byteEncrypted = Convert.FromBase64String (sEncryptedText.Trim ()); PlaintextStream = new MemoryStream (sEncryptedText.Length); Decryptor = GetDecryptor (); TheCryptoStream = new CryptoStream (PlaintextStream, Decryptor, CryptoStreamMode.Write); TheCryptoStream.Write (byteEncrypted, 0, byteEncrypted.Length); TheCryptoStream.FlushFinalBlock (); TheCryptoStream.Close (); return Encoding.ASCII.GetString (PlaintextStream.ToArray () );