DES加解密

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Security.Cryptography;
using System.IO;

namespace Win.Secure
{
    public partial class FrmMain : Form
    {
        public FrmMain()
        {
            InitializeComponent();
        }

        private void FrmMain_Load(object sender, EventArgs e)
        {

        }

        // 密文
        private string key = "H8x_2h1`";

        /// <summary>
        /// DEC 加密过程
        /// </summary>
        /// <param name="pToEncrypt"></param>
        /// <param name="sKey"></param>
        /// <returns></returns>
        public string Encrypt(string pToEncrypt, string sKey)
        {
            // 把字符串放到byte数组中   
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();   
            byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
            // 建立加密对象的密钥和偏移量 
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            // 原文使用ASCIIEncoding.ASCII方法的GetBytes方法  
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            // 使得输入密码必须输入英文文本 
            MemoryStream ms = new 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);
            }
            ret.ToString();
            return ret.ToString();
        }

        /// <summary>
        /// DEC 解密过程
        /// </summary>
        /// <param name="pToDecrypt"></param>
        /// <param name="sKey"></param>
        /// <returns></returns>
        public string Decrypt(string pToDecrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
            for (int x = 0; x < pToDecrypt.Length / 2; x++)
            {
                int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
                inputByteArray[x] = (byte)i;
            }
            // 建立加密对象的密钥和偏移量，此值重要，不能修改   
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);   
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            // 建立StringBuild对象，CreateDecrypt使用的是流对象，必须把解密后的文本变成流对象  
            StringBuilder ret = new StringBuilder();    
            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string str = Encrypt(textBox1.Text, key);
            textBox2.Text = str;
            label1.Text = str.Length.ToString();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            textBox1.Text = Decrypt(textBox2.Text, key);
        }  
    }
}