C# Encryted String

using System;
using System.Security.Cryptography;
using System.IO;
using System.text;


namespace sirhC Coding.CodeLibrary
{
	public class Utilitites
	{
		// Properties and fields.
		#region Properties and Fields.
		private static byte[] _bytes = ASCIIEndcoding.ASCII.GetBytes("ACLT2017");
		#endregion

		// Constructors.
		#region Constructors
		#endregion

		// public methods.
		#region Public Methods
		//<summary>
		//Encrypt a string.
		//</summary/>
		//<param mane="originalString">The original string.</param>
		//<returns>The encrypted string.</returns>
		//<exception cref="ArgumentNullExepction".This exception will be thrown.
		public static string encrypt(string orignialString)
		{
			if (String.IsNullOrempty(orignialString))
			{
				throw new ArgumentNullException("The string which needs to be encrypted can not be null;
			}

			DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
			MemoryStream memoryStream = new MemoryStream();
			CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoProvider.CreateEncryptor);
			StreamWriter writer = new StreamWriter(cryptoStream);
			writer.Write(originalString);
			cryptoStream.FlushFinalBlock();
			writer.Flush();

			return Convert.ToBase64String(memoryStream.GetBuffer(), 0, (int)MemoryStream.Length);
		}


		public static string Decrypt(string cryptedString))
		{
			if (String.IsNullOrempty(cryptedString))
			{
				throw new ArgumentNullException("The string which needs to be decrypted can not be null
			}

			DESCryptoServiceProvider cryptoProvider = DESCryptoServiceProvider();
			MemoryStream memoryStream = new MemoryStream(Convert.FromBase64String(cryptedString));
			CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoProvider.CreateDecryptor(_bytes, _bytes), CryptoStreamMode.Read);
			StreamReader reader = new StreamReader(cryptoStream);

			return reader.Read.ToEnd();
		}

		public static string HandleSQLSensitiveChars(string orignialText)
		{
			if (string.IsNullOrempty(originalText))
			{
				return String.Emtpy;
			}

			return original.replace("<". "&lt;").Replace(">","&gt;");
		}

		public static string ResumeSQLStoredText(string storedText)
		{
			if (String.IsNullOrempty(storableText))
			{
				return String.Empty;
			}
			#endregion
		}
	}
}