asp.net EncryptHelper 加密帮助类

/************************************************** 
* 版权所有: Mr_Sheng 
* 文 件 名: EncryptHelper.cs 
* 文件描述: 
* 类型说明: EncryptHelper 加密帮助类 
* 授权声明: 
* 本程序为自由软件； 
* 您可依据自由软件基金会所发表的GPL v3授权条款，对本程序再次发布和/或修改； 
* 本程序是基于使用目的而加以发布，然而不负任何担保责任； 
* 亦无对适售性或特定目的适用性所为的默示性担保。 
* 详情请参照GNU通用公共授权 v3（参见license.txt文件）。 
* 版本历史: 
* v2.0.0 Mr_Sheng 2009-09-09 修改 
* 
***************************************************/ 
using System; 
using System.Collections.Generic; 
using System.Text; 
using System.Security.Cryptography; 

namespace Sheng.Common 
{ 
/// <summary> 
/// 加密帮助类 
/// </summary> 
public class EncryptHelper 
{ 
/// <summary> 
/// MD5加密 
/// </summary> 
/// <param name="str"></param> 
/// <returns></returns> 
public static string MD5DecryptString(string str) 
{ 
MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider(); 
byte[] md5Source = System.Text.Encoding.UTF8.GetBytes(str); 
byte[] md5Out = md5.ComputeHash(md5Source); 
return Convert.ToBase64String(md5Out); 
} 

/// <summary> 
/// DES加密字符串 
/// </summary> 
/// <param name="sInputString">输入字符</param> 
/// <param name="sKey">Key</param> 
/// <returns>加密结果</returns> 
public string DESEncryptString(string sInputString, string sKey) 
{ 
try 
{ 
byte[] data = Encoding.Default.GetBytes(sInputString); 
byte[] result; 
DESCryptoServiceProvider DES = new DESCryptoServiceProvider(); 
DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey); //密钥 
DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey); //初始化向量 
ICryptoTransform desencrypt = DES.CreateEncryptor(); //加密器对象 
result = desencrypt.TransformFinalBlock(data, 0, data.Length); //转换指定字节数组的指定区域 
return BitConverter.ToString(result); 
} 
catch (Exception ex) 
{ 
//ex.Message = "DES加密异常"; 
throw ex; 
} 
} 

/// <summary> 
/// DES解密字符串 
/// </summary> 
/// <param name="sInputString">输入字符</param> 
/// <param name="sKey">Key</param> 
/// <returns>解密结果</returns> 
public string DESDecryptString(string sInputString, string sKey) 
{ 
try 
{ 
//将字符串转换为字节数组 
string[] sInput = sInputString.Split("-".ToCharArray()); 
byte[] data = new byte[sInput.Length]; 
byte[] result; 
for (int i = 0; i < sInput.Length; i++) 
{ 
data[i] = byte.Parse(sInput[i], System.Globalization.NumberStyles.HexNumber); 
} 

DESCryptoServiceProvider DES = new DESCryptoServiceProvider(); 
DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey); 
DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey); 
ICryptoTransform desencrypt = DES.CreateDecryptor(); 
result = desencrypt.TransformFinalBlock(data, 0, data.Length); 
return Encoding.Default.GetString(result); 
} 
catch (Exception ex) 
{ 
//ex.Message = "DES解密异常"; 
throw ex; 
} 
} 
} 
}