C#加密幫助類EncryptHelper

using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Runtime.Serialization.Formatters.Binary;

using System.Security.Cryptography;

using System.Text;

using log4net;

namespace Utility

{

    /// <summary>

    /// @Author:梁繼龍

    /// @Date:2012/7/30

    /// @Descripte:EncryptHelper加密幫助類.

    /// </summary>

    public class EncryptHelper

    {

        /// <summary>

        ///方法一:

        ///此種加密之后的字符串是三十二位的(字母加數據)字符串

        /// Example: password是admin 加密變成后21232f297a57a5a743894a0e4a801fc3

        /// </summary>

        /// <param name="beforeStr"></param>

        /// <returns></returns>

        public string MD5Encrypt(string beforeStr)

        {

            string afterString = "";

            try

            {

                MD5 md5 = MD5.Create();

                byte[] hashs = md5.ComputeHash(Encoding.UTF8.GetBytes(beforeStr));

            foreach (byte by in hashs)  
                //這里是字母加上數據進行加密.//3y 可以,y3不可以或 x3j等應該是超過32位不可以  
                afterString += by.ToString("x2");  
        }  
        catch (Exception ex)  
        {  
            ILog log = log4net.LogManager.GetLogger(this.GetType());  
            log.Error("==============你引起了一個錯誤是==============" + ex.Message.ToString());  
        }  
        return afterString;  
    }  

    /// <summary>  
    /// 方法二  
    /// HashAlgorithm加密  
    /// 這種加密是  字母加-加字符    
    /// Example: password是admin 加密變成后19-A2-85-41-44-B6-3A-8F-76-17-A6-F2-25-01-9B-12  
    /// </summary>  
    /// <param name="password"></param>  
    /// <returns></returns>  
    public String HashEncrypt(string password)  
    {  
        Byte[] hashedBytes = null;  
        try  
        {  
            Byte[] clearBytes = new UnicodeEncoding().GetBytes(password);  
            hashedBytes = ((HashAlgorithm)CryptoConfig.CreateFromName("MD5")).ComputeHash(clearBytes);  
        }  
        catch (Exception ex)  
        {  
            ILog log = log4net.LogManager.GetLogger(this.GetType());  
            log.Error("==============你引起了一個錯誤是==============" + ex.Message.ToString());  
        }  
        return BitConverter.ToString(hashedBytes);//MD5加密  
    }  

    /// <summary>  
    /// 方法三:  
    /// MD5  +   HashCode加密  
    /// Example: password是admin 加密變成后 895b7da64943134be17b825ce118456c  
    /// </summary>  
    /// <returns></returns>  
    public String MD5HashCodeEncrypt(string EncryptPwd)  
    {  
        return MD5Encrypt(HashEncrypt(EncryptPwd)); //在HashEncrypt基礎上再MD5  
    }  

    /// <summary>  
    /// 方法四:  
    /// HashCode +MD5 加密  
    /// Example: password是admin 加密變成后EB-1D-6D-E2-FC-F1-CD-94-4D-75-78-E6-3D-7A-12-32  
    /// </summary>  
    /// <param name="EncryptPwd"></param>  
    /// <returns></returns>  
    public String HashCodeMD5Encrypt(string EncryptPwd)  
    {  
        return HashEncrypt(MD5Encrypt(EncryptPwd)); //在MD5基礎再HashCode  
    }  
    /// <summary>  
    /// 方法五  
    /// </summary>  
    /// <param name="EncryptPwd"></param>  
    /// <returns></returns>  

    public String HashMD5Encrypt(string EncryptPwd)  
    {  
        return HashCodeMD5Encrypt(HashCodeMD5Encrypt(EncryptPwd)); //在HashCodeMD5Encrypt基礎再HashCode  
    }  
    /// <summary>  
    /// 方法六  
    /// 哈哈是不是有點暈呢？  
    /// 大家伙可以繼續寫.  
    /// </summary>  
    /// <param name="EncryptPwd"></param>  
    /// <returns></returns>  
    public String MD5HashEncrypt(string EncryptPwd)  
    {  
        return MD5HashCodeEncrypt(MD5HashCodeEncrypt(EncryptPwd)); //在MD5基礎再HashCode  
    }  
    /// <summary>  
    /// 64位雙重MD5小寫  
    /// </summary>  
    /// <returns></returns>  
    public static string Last64(string s)  
    {  
        if (s.Length != 32)  
            return "";  
        string s1 = s.Substring(0, 16);  
        string s2 = s.Substring(16, 16);  
        return Lower32(s1) + Lower32(s2);  
    }  
    /// <summary>  
    /// 32位大寫  
    /// </summary>  
    /// <returns></returns>  
    public static string Upper32(string s)  
    {  
        s = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(s, "md5").ToString();  
        return s.ToUpper();  
    }  
    /// <summary>  
    /// 32位小寫  
    /// </summary>  
    /// <returns></returns>  
    public static string Lower32(string s)  
    {  
        s = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(s, "md5").ToString();  
        return s.ToLower();  
    }  
    /// <summary>  
    /// 16位大寫  
    /// </summary>  
    /// <returns></returns>  
    public static string Upper16(string s)  
    {  
        s = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(s, "md5").ToString();  
        return s.ToUpper().Substring(8, 16);  
    }  
    /// <summary>  
    /// 16位小寫  
    /// </summary>  
    /// <returns></returns>  
    public static string Lower16(string s)  
    {  
        s = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(s, "md5").ToString();  
        return s.ToLower().Substring(8, 16);  
    }  
}  


}  </pre>