DES加密/解密类。 | 易学教程

using System;
using System.Security.Cryptography;
using System.Text;
namespace ROYcms.DB
{
/// <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,"ROYcms");
  }
  /// <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, "ROYcms");
  }
  /// <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

}
}

来源：https://www.cnblogs.com/modernsky2003/archive/2010/03/03/1677188.html

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des加密

string类