MD5加密错误？？？

Question

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Web.Security;
using System.Security.Cryptography;
/// <summary>
/// Summary description for encrypting.
/// </summary>
public class encrypting : System.Web.UI.Page
{
protected System.Web.UI.WebControls.Label MD5;
protected System.Web.UI.WebControls.Button Button1;
protected System.Web.UI.WebControls.TextBox TextBox1;public encrypting()
{
Page.Init += new System.EventHandler(Page_Init);
}
protected void Page_Load(object sender, EventArgs e)
{}
protected void Page_Init(object sender, EventArgs e)
{InitializeComponent();
}private void InitializeComponent()
{
Button1.Click += new System.EventHandler (this.Button1_Click);
this.Load += new System.EventHandler (this.Page_Load);
}
public void Button1_Click (object sender, System.EventArgs e)
{
MD5.Text = CookieAuthentication.HashPasswordForStoringInConfigFile(TextBox1.Text,"MD5");}
}
}
编译错误 
说明: 在编译向该请求提供服务所需资源的过程中出现错误。请检查下列特定错误详细信息并适当地修改源代码。 编译器错误信息: CS0246: 找不到类型或命名空间名称“CookieAuthentication”(是否缺少 using 指令或程序集引用？)源错误: 行 45： public void Button1_Click (object sender, System.EventArgs e)
行 46： {
行 47： MD5.Text = CookieAuthentication.HashPasswordForStoringInConfigFile(TextBox1.Text,"MD5"); 

Answer 1

MD5.Text =FormsAuthentication.HashPasswordForStoringInConfigFile(TextBox1.Text,"MD5");

Answer 2

我自己写的加密类,你可以参考:
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text; public class Crypto
{

private SymmetricAlgorithm mobjCryptoService;
private string Key;
/// <summary>
/// 对称加密类的构造函数
/// </summary>
public Crypto()
{
mobjCryptoService = new RijndaelManaged();
Key = "Guz(%&hj7x89H$yuBI0456FtmaT5&fvHUFCy76*h%(HilJ$lhj!y6&(*jkP87jH7";

}
/// <summary>
/// 获得密钥
/// </summary>
/// <returns>密钥</returns>
private byte[] GetLegalKey()
{
string sTemp = Key;
mobjCryptoService.GenerateKey();
byte[] bytTemp = mobjCryptoService.Key;
int KeyLength = bytTemp.Length;
if (sTemp.Length > KeyLength)
sTemp = sTemp.Substring(0, KeyLength);
else if (sTemp.Length < KeyLength)
sTemp = sTemp.PadRight(KeyLength, ' ');
return ASCIIEncoding.ASCII.GetBytes(sTemp);
}
/// <summary>
/// 获得初始向量IV
/// </summary>
/// <returns>初试向量IV</returns>
private byte[] GetLegalIV()
{
string sTemp = "E4ghj*Ghg7!rNIfb&95GUY86GfghUb#er57HBh(u%g6HJ($jhWk7&!hg4ui%$hjk";
mobjCryptoService.GenerateIV();
byte[] bytTemp = mobjCryptoService.IV;
int IVLength = bytTemp.Length;
if (sTemp.Length > IVLength)
sTemp = sTemp.Substring(0, IVLength);
else if (sTemp.Length < IVLength)
sTemp = sTemp.PadRight(IVLength, ' ');
return ASCIIEncoding.ASCII.GetBytes(sTemp);
}
/// <summary>
/// 加密方法
/// </summary>
/// <param name="Source">待加密的串</param>
/// <returns>经过加密的串</returns>
public string Encrypto(string Source)
{
byte[] bytIn = UTF8Encoding.UTF8.GetBytes(Source);
MemoryStream ms = new MemoryStream();
mobjCryptoService.Key = GetLegalKey();
mobjCryptoService.IV = GetLegalIV();
ICryptoTransform encrypto = mobjCryptoService.CreateEncryptor();
CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);
cs.Write(bytIn, 0, bytIn.Length);
cs.FlushFinalBlock();
ms.Close();
byte[] bytOut = ms.ToArray();
return Convert.ToBase64String(bytOut);
}
/// <summary>
/// 解密方法
/// </summary>
/// <param name="Source">待解密的串</param>
/// <returns>经过解密的串</returns>
public string Decrypto(string Source)
{
byte[] bytIn = Convert.FromBase64String(Source);
MemoryStream ms = new MemoryStream(bytIn, 0, bytIn.Length);
mobjCryptoService.Key = GetLegalKey();
mobjCryptoService.IV = GetLegalIV();
ICryptoTransform encrypto = mobjCryptoService.CreateDecryptor();
CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);
StreamReader sr = new StreamReader(cs);
return sr.ReadToEnd();
} }
}

Answer 3

C:\Documents and Settings\cwr\My Documents\Visual Studio Projects\TEST\Form1.cs(94): 找不到类型或命名空间名称“FormsAuthentication”(是否缺少 using 指令或程序集引用？)