using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Security.Cryptography;
using System.IO;
namespace _3DES
{
  public partial class Form1 : Form
  {
    public Form1()
    {
      InitializeComponent();
    }
    private void CrypeBtn_Click(object sender, EventArgs e)
    {
      //实例化三倍DES服务提供者类
      TripleDESCryptoServiceProvider TDES = new TripleDESCryptoServiceProvider();
      //随机生成密钥和IV向量
      TDES.GenerateIV();
      TDES.GenerateKey();
      //执行加密
      byte[] EncrypeByte = EncrypText(StrBox.Text, TDES.Key, TDES.IV);
      //显示密文和密钥
      KeyBox.Text = Encoding.ASCII.GetString(TDES.Key);
      IVBox.Text = Encoding.ASCII.GetString(TDES.IV);
      CrypeBox.Text = Encoding.UTF8.GetString(EncrypeByte);
      //执行解密
      Str2Box.Text = DecrypText(EncrypeByte, TDES.Key, TDES.IV);
    }
    #region 加密
    /// <summary>
    /// 执行三倍DES加密的方法
    /// </summary>
    /// <param name="Str">明文字符串</param>
    /// <param name="Key">密钥</param>
    /// <param name="IV">IV向量</param>
    /// <returns>密文的字节序列</returns>
    private byte[] EncrypText(string Str, byte[] Key, byte[] IV)
    {
      //创建一个内存流，用于存放密文
      MemoryStream MS = new MemoryStream();
      //创建一个三倍DES服务提供者对象
      TripleDESCryptoServiceProvider TDES = new TripleDESCryptoServiceProvider();
      //创建一个加密流，用于加密操作
      CryptoStream CS = new CryptoStream(MS,
        TDES.CreateEncryptor(Key, IV),
        CryptoStreamMode.Write);
      //定义输入，执行加密操作
      CS.Write(Encoding.UTF8.GetBytes(Str), 0, Str.Length);
      CS.FlushFinalBlock();
      //返回将密文的内存流转换为字节序列并返回
      return MS.ToArray();
    }
    #endregion
    #region 解密
    /// <summary>
    /// 执行三倍DES解密的方法
    /// </summary>
    /// <param name="CrypeText">密文的字节序列</param>
    /// <param name="Key">密钥</param>
    /// <param name="IV">IV向量</param>
    /// <returns>明文的字符串</returns>
    private string DecrypText(byte[] CrypeText, byte[] Key, byte[] IV)
    {
      //创建一个内存流，用于存放密文
      MemoryStream MS = new MemoryStream(CrypeText);
      //创建一个三倍DES服务提供者对象
      TripleDESCryptoServiceProvider TDES = new TripleDESCryptoServiceProvider();
      //创建解密流
      CryptoStream CS = new CryptoStream(MS,
        TDES.CreateDecryptor(Key, IV),
        CryptoStreamMode.Read);
      //创建一个用于存放明文的容器（字节序列）
      byte[] DecrypeBytes = new byte[CrypeText.Length];
      //执行解密
      CS.Read(DecrypeBytes, 0, CrypeText.Length);
      //返回解密后的明文字符串
      return Encoding.UTF8.GetString(DecrypeBytes);
    }
    #endregion
  }
}