.NET加密与解密类(DES)

DES  对称加密算法
DES-Data Encryption Standard,即数据加密算法。是IBM公司于1975年研究成功并公开发表的。DES算法的入口参数有三个:Key、Data、Mode。其中Key为8个字节共64位,是DES算法的工作密钥;Data也为8个字节64位,是要被加密或被解密的数据;Mode为DES的工作方式,有两种:加密或解密。
　　DES算法把64位的明文输入块变为64位的密文输出块,它所使用的密钥也是64位。

using System;
using System.Security.Cryptography; 
using System.Text;

namespace Common.DES
{
 /// <summary>
 /// DES加密/解密类。
 /// </summary>
 public class DESEncrypt
 {
  public DESEncrypt()
  {   
  }

  #region ========加密========
 
        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="Text"></param>
        /// <returns></returns>
  public static string Encrypt(string Text)
  {
            return Encrypt(Text, "liyanling");
  }
  /// <summary>
  /// 加密数据
  /// </summary>
  /// <param name="Text"></param>
  /// <param name="sKey"></param>
  /// <returns></returns>
  public static string Encrypt(string Text,string sKey)
  {
   DESCryptoServiceProvider des = new DESCryptoServiceProvider();
   byte[] inputByteArray;
   inputByteArray=Encoding.Default.GetBytes(Text);
   des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
   des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
   System.IO.MemoryStream ms=new System.IO.MemoryStream();
   CryptoStream cs=new CryptoStream(ms,des.CreateEncryptor(),CryptoStreamMode.Write);
   cs.Write(inputByteArray,0,inputByteArray.Length);
   cs.FlushFinalBlock();
   StringBuilder ret=new StringBuilder();
   foreach( byte b in ms.ToArray())
   {
    ret.AppendFormat("{0:X2}",b);
   }
   return ret.ToString();
  }

  #endregion
  
  #region ========解密========
  
 
        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="Text"></param>
        /// <returns></returns>
  public static string Decrypt(string Text)
  {
            return Decrypt(Text, "liyanling");
  }
  /// <summary>
  /// 解密数据
  /// </summary>
  /// <param name="Text"></param>
  /// <param name="sKey"></param>
  /// <returns></returns>
  public static string Decrypt(string Text,string sKey)
  {
   DESCryptoServiceProvider des = new DESCryptoServiceProvider();
   int len;
   len=Text.Length/2;
   byte[] inputByteArray = new byte[len];
   int x,i;
   for(x=0;x<len;x++)
   {
    i = Convert.ToInt32(Text.Substring(x * 2, 2), 16);
    inputByteArray[x]=(byte)i;
   }
   des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
   des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
   System.IO.MemoryStream ms=new System.IO.MemoryStream();
   CryptoStream cs=new CryptoStream(ms,des.CreateDecryptor(),CryptoStreamMode.Write);
   cs.Write(inputByteArray,0,inputByteArray.Length);
   cs.FlushFinalBlock();
   return Encoding.Default.GetString(ms.ToArray());
  }
 
  #endregion

 }
}