String Encryption

Ecco come criptare e decriptare una semplice stringa di testo:private static byte[] arrDESKey = new byte[] {12, 16, 63, 156, 58, 4, 218, 32};private static byte[] arrDESIV = new byte[] {55, 103, 243, 79, 36, 99, 17, 3};        public static string Encrypt(string str)        {            DESCryptoServiceProvider objDES = new DESCryptoServiceProvider();            MemoryStream objMemoryStream = new MemoryStream();            CryptoStream objCryptoStream = new CryptoStream(objMemoryStream,objDES.CreateEncryptor(arrDESKey,arrDESIV),CryptoStreamMode.Write);            StreamWriter objStreamWriter = new StreamWriter(objCryptoStream);            objStreamWriter.Write(str);            objStreamWriter.Flush();            objCryptoStream.FlushFinalBlock();            objMemoryStream.Flush();            return Convert.ToBase64String(objMemoryStream.GetBuffer(), 0, (int)objMemoryStream.Length);        }        public static string Decrypt(string str)        {            DESCryptoServiceProvider objDES = new DESCryptoServiceProvider();            byte[] arrInput = Convert.FromBase64String(str);            MemoryStream objMemoryStream = new MemoryStream(arrInput);            CryptoStream objCryptoStream = new CryptoStream(objMemoryStream,objDES.CreateDecryptor(arrDESKey,arrDESIV),CryptoStreamMode.Read);            StreamReader  objStreamReader  = new StreamReader(objCryptoStream);            return objStreamReader.ReadToEnd();        }