TcpClient在C#中的SSL/TLS加密通信

在C#中，使用TcpClient进行SSL/TLS加密通信需要使用SslStream类

using System;
using System.IO;
using System.Net.Security;
using System.Net.Sockets;
using System.Security.Authentication;
using System.Text;

namespace TcpClientSslDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            // 服务器地址和端口
            string serverAddress = "example.com";
            int serverPort = 443;

            // 创建TcpClient实例
            using (TcpClient client = new TcpClient(serverAddress, serverPort))
            {
                // 获取网络流
                NetworkStream networkStream = client.GetStream();

                // 创建SslStream实例
                using (SslStream sslStream = new SslStream(networkStream, false, ValidateServerCertificate))
                {
                    // 开始SSL/TLS握手
                    sslStream.AuthenticateAsClient(serverAddress, null, SslProtocols.Tls12, true);

                    // 发送数据
                    byte[] message = Encoding.UTF8.GetBytes("GET / HTTP/1.1\r\nHost: example.com\r\nConnection: close\r\n\r\n");
                    sslStream.Write(message);

                    // 接收数据
                    byte[] buffer = new byte[2048];
                    int bytesRead = sslStream.Read(buffer, 0, buffer.Length);

                    // 处理接收到的数据
                    string response = Encoding.UTF8.GetString(buffer, 0, bytesRead);
                    Console.WriteLine(response);
                }
            }
        }

        // 验证服务器证书的回调函数
        public static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
        {
            if (sslPolicyErrors == SslPolicyErrors.None)
                return true;

            Console.WriteLine("Certificate error: {0}", sslPolicyErrors);
            return false;
        }
    }
}

这个示例展示了如何使用TcpClient和SslStream类创建一个简单的客户端，连接到服务器并进行SSL/TLS加密通信。请注意，这个示例仅用于演示目的，实际应用中可能需要根据具体需求进行修改。