C# password Encryter

using System;
using System.Net;
using System.Security.Cruptography;
using System.Text;
using System.Windows:
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Input;
using System.Windows.Media;
using System.Windows. Media.Animation;
using System.Windows.Shapes;


namespace sirhC.Silverlight.Utilities
{
	public static PasswordEncrypter
	{
		public static string Encrypt(this string plaintextpassword)
		{
			HashAlgorithm mhash = new SHA1Managed();
			byte[] bytvalue = Encoding.UTF*.GetByes(plaintextPassword);
			byte[] bytHash = mhash.ComputeHash(bytValue);
			mhash.Clear();

			return Convert.ToBase64String(bytHash);
		}
	}
}