C# DES

using System;
//这个是使用DES的基础
using System.Security.Cryptography;
//这个是处理文字编码的前提
using System.Text;
//以“流”的形式处理文字，也是微软DES算法要求的
using System.IO;
/// <summary>
/// DES加密方法
/// </summary>
/// <param name="strPlain">明文</param>
/// <param name="strDESKey">密钥</param>
/// <param name="strDESIV">向量</param>
/// <returns>密文</returns>
public string DESEncrypt(string strPlain,string strDESKey,string strDESIV)
{
//把密钥转换成字节数组
byte[] bytesDESKey=ASCIIEncoding.ASCII.GetBytes(strDESKey);
//把向量转换成字节数组
byte[] bytesDESIV=ASCIIEncoding.ASCII.GetBytes(strDESIV);
//声明1个新的DES对象
DESCryptoServiceProvider desEncrypt=new DESCryptoServiceProvider();
//开辟一块内存流
MemoryStream msEncrypt=new MemoryStream();
//把内存流对象包装成加密流对象
CryptoStream csEncrypt=new CryptoStream(msEncrypt,desEncrypt.CreateEncryptor(bytesDESKey,bytesDESIV),CryptoStreamMode.Write);
//把加密流对象包装成写入流对象
StreamWriter swEncrypt=new StreamWriter(csEncrypt);
//写入流对象写入明文
swEncrypt.WriteLine(strPlain);
//写入流关闭
swEncrypt.Close();
//加密流关闭
csEncrypt.Close();
//把内存流转换成字节数组，内存流现在已经是密文了
byte[] bytesCipher=msEncrypt.ToArray();
//内存流关闭
msEncrypt.Close();
//把密文字节数组转换为字符串，并返回
return UnicodeEncoding.Unicode.GetString(bytesCipher);
}
/// <summary>
/// DES解密方法
/// </summary>
/// <param name="strCipher">密文</param>
/// <param name="strDESKey">密钥</param>
/// <param name="strDESIV">向量</param>
/// <returns>明文</returns>
public string DESDecrypt(string strCipher,string strDESKey,string strDESIV)
{
//把密钥转换成字节数组
byte[] bytesDESKey=ASCIIEncoding.ASCII.GetBytes(strDESKey);
//把向量转换成字节数组
byte[] bytesDESIV=ASCIIEncoding.ASCII.GetBytes(strDESIV);
//把密文转换成字节数组
byte[] bytesCipher=UnicodeEncoding.Unicode.GetBytes(strCipher);
//声明1个新的DES对象
DESCryptoServiceProvider desDecrypt=new DESCryptoServiceProvider();
//开辟一块内存流，并存放密文字节数组
MemoryStream msDecrypt=new MemoryStream(bytesCipher);
//把内存流对象包装成解密流对象
CryptoStream csDecrypt=new CryptoStream(msDecrypt,desDecrypt.CreateDecryptor(bytesDESKey,bytesDESIV),CryptoStreamMode.Read);
//把解密流对象包装成读出流对象
StreamReader srDecrypt=new StreamReader(csDecrypt);
//明文=读出流的读出内容
string strPlainText=srDecrypt.ReadLine();
//读出流关闭
srDecrypt.Close();
//解密流关闭
csDecrypt.Close();
//内存流关闭
msDecrypt.Close();
//返回明文
return strPlainText;
}