在很多项目中，为了安全安全考虑，需要对数据包进行加密处理，本文实例所述的即为C#加密代码，在应用开发中有很大的实用价值。说起数据包加密，其实对C#编程者来说，应该是一个基础的技巧，是进行C#程序设计人员必须要掌握的技能。

C#实现加密功能的核心代码如下：

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.Threading; using System.Net; using System.Net.Sockets; using System.Net.NetworkInformation; using System.Security.Cryptography; using System.IO; namespace EncryptDataReport { public partial class Form1 : Form { public Form1() { InitializeComponent(); } #region 定义全局对象及变量 private IPEndPoint Server;//服务器端 private IPEndPoint Client;//客户端 private Socket mySocket;//套接字 private EndPoint ClientIP;//IP地址 byte[] buffer, data;//接收缓存 bool blFlag = true;//标识是否第一次发送信息 bool ISPort = false;//判断端口打开 int SendNum1, ReceiveNum1, DisNum1; //记录窗体加载时的已发送已接收丢失的数据报 int SendNum2, ReceiveNum2, DisNum2; //记录当前已发送已接收丢失的数据报 int SendNum3, ReceiveNum3, DisNum3; //缓存已发送已接收丢失的数据报 int port;//端口号 #endregion //异步接收信息 private void StartLister(IAsyncResult IAResult) { int Num = mySocket.EndReceiveFrom(IAResult, ref ClientIP); string strInfo = Encoding.Unicode.GetString(buffer, 0, Num); rtbContent.AppendText("用户" + ClientIP.ToString()); rtbContent.AppendText("："); rtbContent.AppendText("rn"); rtbContent.AppendText(DecryptDES(strInfo, "mrsoftxk"));//对接收到的信息进行解密 rtbContent.AppendText("rn"); mySocket.BeginReceiveFrom(buffer, 0, buffer.Length, SocketFlags.None, ref ClientIP, new AsyncCallback(StartLister), null); } //初始化已发送、已接收和丢失的数据报 private void Form1_Load(object sender, EventArgs e) { if (blFlag == true) { IPGlobalProperties NetInfo = IPGlobalProperties.GetIPGlobalProperties(); UdpStatistics myUdpStat = null; myUdpStat = NetInfo.GetUdpIPv4Statistics(); SendNum1 = Int32.Parse(myUdpStat.DatagramsSent.ToString()); ReceiveNum1 = Int32.Parse(myUdpStat.DatagramsReceived.ToString()); DisNum1 = Int32.Parse(myUdpStat.IncomingDatagramsDiscarded.ToString()); } } //设置端口号 private void button4_Click(object sender, EventArgs e) { try { port = Convert.ToInt32(textBox4.Text); CheckForIllegalCrossThreadCalls = false; buffer = new byte[1024]; data = new byte[1024]; Server = new IPEndPoint(IPAddress.Any, port); Client = new IPEndPoint(IPAddress.Broadcast, port); ClientIP = (EndPoint)Server; mySocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp); mySocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1); mySocket.Bind(Server); mySocket.BeginReceiveFrom(buffer, 0, buffer.Length, SocketFlags.None, ref ClientIP, new AsyncCallback(StartLister), null); ISPort = true;//打开指定端口号 } catch { } } //发送信息 private void button2_Click(object sender, EventArgs e) { if (ISPort == true)//判断是否有打开的端口号 { IPGlobalProperties NetInfo = IPGlobalProperties.GetIPGlobalProperties(); UdpStatistics myUdpStat = null; myUdpStat = NetInfo.GetUdpIPv4Statistics(); try { if (blFlag == false)//非第一次发送 { SendNum2 = Int32.Parse(myUdpStat.DatagramsSent.ToString()); ReceiveNum2 = Int32.Parse(myUdpStat.DatagramsReceived.ToString()); DisNum2 = Int32.Parse(myUdpStat.IncomingDatagramsDiscarded.ToString()); textBox1.Text = Convert.ToString(SendNum2 - SendNum3); textBox2.Text = Convert.ToString(ReceiveNum2 - ReceiveNum3); textBox3.Text = Convert.ToString(DisNum2 - DisNum3); } SendNum2 = Int32.Parse(myUdpStat.DatagramsSent.ToString()); ReceiveNum2 = Int32.Parse(myUdpStat.DatagramsReceived.ToString()); DisNum2 = Int32.Parse(myUdpStat.IncomingDatagramsDiscarded.ToString()); SendNum3 = SendNum2; //记录本次的发送数据报 ReceiveNum3 = ReceiveNum2;//记录本次的接收数据报 DisNum3 = DisNum2; //记录本次的丢失数据报 if (blFlag == true)//第一次发送 { textBox1.Text = Convert.ToString(SendNum2 - SendNum1); textBox2.Text = Convert.ToString(ReceiveNum2 - ReceiveNum1); textBox3.Text = Convert.ToString(DisNum2 - DisNum1); blFlag = false; } } catch (Exception ex) { MessageBox.Show(ex.Message, "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Information); } string str = EncryptDES(rtbSend.Text, "mrsoftxk");//加密要发送的信息 data = Encoding.Unicode.GetBytes(str); mySocket.SendTo(data, data.Length, SocketFlags.None, Client); rtbSend.Text = ""; } else { MessageBox.Show("请首先打开端口！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information); button4.Focus(); } } //清屏 private void button1_Click(object sender, EventArgs e) { rtbContent.Clear(); } //退出 private void button3_Click(object sender, EventArgs e) { Application.Exit(); } //按<Ctrl+Enter>组合键发送信息 private void rtbSend_KeyDown(object sender, KeyEventArgs e) { //当同时按下Ctrl和Enter时，发送消息 if (e.Control && e.KeyValue == 13) { e.Handled = true; button2_Click(this, null); } } //聊天记录随时滚动 private void rtbContent_TextChanged(object sender, EventArgs e) { rtbContent.ScrollToCaret(); } private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };//密钥 #region DES加密字符串 ///<summary> ///DES加密字符串 ///</summary> ///<param name="str">待加密的字符串</param> ///<param name="key">加密密钥,要求为8位</param> ///<returns>加密成功返回加密后的字符串，失败返回源字符串</returns> public string EncryptDES(string str, string key) { try { byte[] rgbKey = Encoding.UTF8.GetBytes(key.Substring(0, 8)); byte[] rgbIV = Keys; byte[] inputByteArray = Encoding.UTF8.GetBytes(str); DESCryptoServiceProvider myDES = new DESCryptoServiceProvider(); MemoryStream MStream = new MemoryStream(); CryptoStream CStream = new CryptoStream(MStream, myDES.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write); CStream.Write(inputByteArray, 0, inputByteArray.Length); CStream.FlushFinalBlock(); return Convert.ToBase64String(MStream.ToArray()); } catch { return str; } } #endregion #region DES解密字符串 ///<summary> ///DES解密字符串 ///</summary> ///<param name="str">待解密的字符串</param> ///<param name="key">解密密钥,要求为8位,和加密密钥相同</param> ///<returns>解密成功返回解密后的字符串，失败返源字符串</returns> public string DecryptDES(string str, string key) { try { byte[] rgbKey = Encoding.UTF8.GetBytes(key); byte[] rgbIV = Keys; byte[] inputByteArray = Convert.FromBase64String(str); DESCryptoServiceProvider myDES = new DESCryptoServiceProvider(); MemoryStream MStream = new MemoryStream(); CryptoStream CStream = new CryptoStream(MStream, myDES.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write); CStream.Write(inputByteArray, 0, inputByteArray.Length); CStream.FlushFinalBlock(); return Encoding.UTF8.GetString(MStream.ToArray()); } catch { return str; } } #endregion } }

本例备有详细的注释，对于开发者而言应该不难理解，读者可以根据自身项目需要改进本例代码以符合自身应用需求。