利用C#实现SSLSocket加密通讯的方法详解

前言

SSL Socket通讯是对socket的扩展，增加Socket通讯的数据安全性，SSL认证分为单向和双向认证。单向认证只认证服务器端的合法性而不认证客户端的合法性。双向认证是同时认证服务端和客户端。下面我分别说说使用C#实现单向认证和双向认证的过程，并用代码实现。

一、 单向认证

第1步：准备一个数字证书，可以使用如下脚本生成

先进入到vs2005的命令行状态，即:

开始–>程序–>Microsoft Visual Studio 2005–>Visual Studio Tools–>Visual Studio 2005 命令提示

键入: makecert -r -pe -n “CN=TestServer” -ss Root -sky exchange

说明：上面的指令将在创建一个受信任的根证书，

第2步创建服务器端程序，代码如下：

using System;
using System.ServiceModel;
using System.Net;
using System.Net.Sockets;
using System.Net.Security;
using System.Text;
using System.Security.Authentication;
using System.Security.Cryptography.X509Certificates;
using System.IdentityModel.Tokens;
using System.IdentityModel.Selectors;

namespace ConsoleApp
{
public class Program
{
static X509Certificate serverCertificate = null;
public static void RunServer()
 {
   TcpListener listener = new TcpListener(IPAddress.Parse("192.168.1.25"), 901);
   listener.Start();
   while (true)
   {
     try
     {
       Console.WriteLine("Waiting for a client to connect...");
       TcpClient client = listener.AcceptTcpClient();
       ProcessClient(client);
     }
     catch
     {
     }
   }
 }

static void ProcessClient(TcpClient client)
 {
   SslStream sslStream = new SslStream(client.GetStream(), false);
   try
   {
     sslStream.AuthenticateAsServer(serverCertificate, false, SslProtocols.Tls, true);
     DisplaySecurityLevel(sslStream);
     DisplaySecurityServices(sslStream);
     DisplayCertificateInformation(sslStream);
     DisplayStreamProperties(sslStream);

sslStream.ReadTimeout = 5000;
     sslStream.WriteTimeout = 5000;
     byte[] message = Encoding.UTF8.GetBytes("Hello from the server.");
     Console.WriteLine("Sending hello message.");
     sslStream.Write(message);
     Console.WriteLine("Waiting for client message...");
     while (true)
     {
       string messageData = ReadMessage(sslStream);
       Console.WriteLine("Received: {0}", messageData);
       if (messageData.ToUpper() == "EXIT")
         break;
     }
   }
   catch (AuthenticationException e)
   {
     Console.WriteLine("Exception: {0}", e.Message);
     if (e.InnerException != null)
     {
       Console.WriteLine("Inner exception: {0}", e.InnerException.Message);
     }
     Console.WriteLine("Authentication failed - closing the connection.");
     sslStream.Close();
     client.Close();
     return;
   }
   finally
   {
     sslStream.Close();
     client.Close();
   }
 }

static string ReadMessage(SslStream sslStream)
 {
   byte[] buffer = new byte[2048];
   StringBuilder messageData = new StringBuilder();
   int bytes = -1;
   do
   {
     bytes = sslStream.Read(buffer, 0, buffer.Length);
     Decoder decoder = Encoding.UTF8.GetDecoder();
     char[] chars = new char[decoder.GetCharCount(buffer, 0, bytes)];
     decoder.GetChars(buffer, 0, bytes, chars, 0);
     messageData.Append(chars);
     if (messageData.ToString().IndexOf("") != -1)
     {
       break;
     }
   }
   while (bytes != 0);

return messageData.ToString();
 }

static void DisplaySecurityLevel(SslStream stream)
 {
   Console.WriteLine("Cipher: {0} strength {1}", stream.CipherAlgorithm, stream.CipherStrength);
   Console.WriteLine("Hash: {0} strength {1}", stream.HashAlgorithm, stream.HashStrength);
   Console.WriteLine("Key exchange: {0} strength {1}", stream.KeyExchangeAlgorithm, stream.KeyExchangeStrength);
   Console.WriteLine("Protocol: {0}", stream.SslProtocol);
 }

static void DisplaySecurityServices(SslStream stream)
 {
   Console.WriteLine("Is authenticated: {0} as server? {1}", stream.IsAuthenticated, stream.IsServer);
   Console.WriteLine("IsSigned: {0}", stream.IsSigned);
   Console.WriteLine("Is Encrypted: {0}", stream.IsEncrypted);
 }

static void DisplayStreamProperties(SslStream stream)
 {
   Console.WriteLine("Can read: {0}, write {1}", stream.CanRead, stream.CanWrite);
   Console.WriteLine("Can timeout: {0}", stream.CanTimeout);
 }

static void DisplayCertificateInformation(SslStream stream)
 {
   Console.WriteLine("Certificate revocation list checked: {0}", stream.CheckCertRevocationStatus);

X509Certificate localCertificate = stream.LocalCertificate;
   if (stream.LocalCertificate != null)
   {
     Console.WriteLine("Local cert was issued to {0} and is valid from {1} until {2}.",
     localCertificate.Subject,
       localCertificate.GetEffectiveDateString(),
       localCertificate.GetExpirationDateString());
   }
   else
   {
     Console.WriteLine("Local certificate is null.");
   }
   X509Certificate remoteCertificate = stream.RemoteCertificate;
   if (stream.RemoteCertificate != null)
   {
     Console.WriteLine("Remote cert was issued to {0} and is valid from {1} until {2}.",
       remoteCertificate.Subject,
       remoteCertificate.GetEffectiveDateString(),
       remoteCertificate.GetExpirationDateString());
   }
   else
   {
     Console.WriteLine("Remote certificate is null.");
   }
 }

private static void DisplayUsage()
 {
   Console.WriteLine("To start the server specify:");
   Console.WriteLine("serverSync certificateFile.cer");
 }

public static void Main(string[] args)
 {
   try
   {
     X509Store store = new X509Store(StoreName.Root);
     store.Open(OpenFlags.ReadWrite);
     // 检索证书
     X509Certificate2Collection certs = store.Certificates.Find(X509FindType.FindBySubjectName, "TestServer", false); // vaildOnly = true时搜索无结果。
     if (certs.Count == 0) return;

serverCertificate = certs[0];
     RunServer();
     store.Close(); // 关闭存储区。
   }
   catch (Exception ex)
   {
     Console.WriteLine(ex.Message);
   }
   Console.ReadLine();
 }
}
}

第3步，创建客户端代码

namespace ConsoleAppClient
{
using System;
using System.Collections;
using System.Net.Security;
using System.Net.Sockets;
using System.Security.Authentication;
using System.Text;
using System.Security.Cryptography.X509Certificates;
namespace Examples.System.Net
{
 public class SslTcpClient
 {
   private static Hashtable certificateErrors = new Hashtable();
   // The following method is invoked by the RemoteCertificateValidationDelegate.
   public static bool ValidateServerCertificate(
      object sender,
      X509Certificate certificate,
      X509Chain chain,
      SslPolicyErrors sslPolicyErrors)
   {
     if (sslPolicyErrors == SslPolicyErrors.None)
       return true;
     Console.WriteLine("Certificate error: {0}", sslPolicyErrors);
     // Do not allow this client to communicate with unauthenticated servers.
     return false;
   }

public static void RunClient(string machineName)
   {
     // Create a TCP/IP client socket.
     // machineName is the host running the server application.
     TcpClient client = new TcpClient(machineName, 901);
     Console.WriteLine("Client connected.");
     // Create an SSL stream that will close the client's stream.
     SslStream sslStream = new SslStream(client.GetStream(), false, new RemoteCertificateValidationCallback(ValidateServerCertificate), null);
     try
     {
       sslStream.AuthenticateAsClient("TestServer");
     }
     catch (AuthenticationException e)
     {
       Console.WriteLine("Exception: {0}", e.Message);
       if (e.InnerException != null)
       {
         Console.WriteLine("Inner exception: {0}", e.InnerException.Message);
       }
       Console.WriteLine("Authentication failed - closing the connection.");
       client.Close();
       return;
     }
     // Encode a test message into a byte array.
     // Signal the end of the message using the "<EOF>".
     byte[] messsage = Encoding.UTF8.GetBytes("Hello from the client.<EOF>");
     // Send hello message to the server.
     sslStream.Write(messsage);
     sslStream.Flush();
     // Read message from the server.
     string serverMessage = ReadMessage(sslStream);
     Console.WriteLine("Server says: {0}", serverMessage);

messsage = Encoding.UTF8.GetBytes("exit");
     sslStream.Write(messsage);
     sslStream.Flush();
     // Close the client connection.
     client.Close();
     Console.WriteLine("Client closed.");
   }

static string ReadMessage(SslStream sslStream)
   {
     // Read the message sent by the server.
     // The end of the message is signaled using the
     // "<EOF>" marker.
     byte[] buffer = new byte[2048];
     StringBuilder messageData = new StringBuilder();
     int bytes = -1;
     do
     {
       bytes = sslStream.Read(buffer, 0, buffer.Length);

// Use Decoder class to convert from bytes to UTF8
       // in case a character spans two buffers.
       Decoder decoder = Encoding.UTF8.GetDecoder();
       char[] chars = new char[decoder.GetCharCount(buffer, 0, bytes)];
       decoder.GetChars(buffer, 0, bytes, chars, 0);
       messageData.Append(chars);
       // Check for EOF.
       if (messageData.ToString().IndexOf("<EOF>") != -1)
       {
         break;
       }
     } while (bytes != 0);

return messageData.ToString();
   }

private static void DisplayUsage()
   {
     Console.WriteLine("To start the client specify:");
     Console.WriteLine("clientSync machineName [serverName]");
     Environment.Exit(1);
   }

public static void Main(string[] args)
   {
     string machineName = null;
     machineName = "192.168.1.25";
     try
     {
       RunClient(machineName);
     }
     catch (Exception ex)
     {
       Console.WriteLine(ex.Message);
     }
     Console.ReadLine();
   }
 }
}
}

运行效果如下图：

导致通讯失败可能问题如下：

1）证书没有导入到受信任的根证书列表中；2）证书失效；3）客户端在使用AuthenticateAsClient注册时没有正确使用服务器端证书名称。

二、 双向认证

第1步：创建所需证书，服务器端所需证书同单向认证中的创建过程

先进入到vs2005的命令行状态，即:

开始–>程序–>Microsoft Visual Studio 2005–>Visual Studio Tools–>Visual Studio 2005 命令提示

键入:

makecert -r -pe -n “CN=TestClient” -ss Root -sky exchange

第2步：创建服务端程序

服务端的程序同单向认证的服务器端代码

第3步：创建客户端程序

namespace ConsoleAppClient
{
using System;
using System.Collections;
using System.Net.Security;
using System.Net.Sockets;
using System.Security.Authentication;
using System.Text;
using System.Security.Cryptography.X509Certificates;
namespace Examples.System.Net
{
 public class SslTcpClient
 {
   private static Hashtable certificateErrors = new Hashtable();
   // The following method is invoked by the RemoteCertificateValidationDelegate.
   public static bool ValidateServerCertificate(
      object sender,
      X509Certificate certificate,
      X509Chain chain,
      SslPolicyErrors sslPolicyErrors)
   {
     if (sslPolicyErrors == SslPolicyErrors.None)
       return true;

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

// Do not allow this client to communicate with unauthenticated servers.
     return false;
   }

public static void RunClient(string machineName)
   {
     // Create a TCP/IP client socket.
     // machineName is the host running the server application.
     TcpClient client = new TcpClient(machineName, 901);
     Console.WriteLine("Client connected.");
     // Create an SSL stream that will close the client's stream.
     SslStream sslStream = new SslStream(client.GetStream(), false, new RemoteCertificateValidationCallback(ValidateServerCertificate), null);
     // The server name must match the name on the server certificate.

X509Store store = new X509Store(StoreName.Root);
     store.Open(OpenFlags.ReadWrite);

//// 检索证书
     X509Certificate2Collection certs = store.Certificates.Find(X509FindType.FindBySubjectName, "TestClient", false);        
     try
     {
       sslStream.AuthenticateAsClient("TestServer", certs, SslProtocols.Tls, false);
     }
     catch (AuthenticationException e)
     {
       Console.WriteLine("Exception: {0}", e.Message);
       if (e.InnerException != null)
       {
         Console.WriteLine("Inner exception: {0}", e.InnerException.Message);
       }
       Console.WriteLine("Authentication failed - closing the connection.");
       client.Close();
       return;
     }
     // Encode a test message into a byte array.
     // Signal the end of the message using the "<EOF>".
     byte[] messsage = Encoding.UTF8.GetBytes("Hello from the client.<EOF>");
     // Send hello message to the server.
     sslStream.Write(messsage);
     sslStream.Flush();
     // Read message from the server.
     string serverMessage = ReadMessage(sslStream);
     Console.WriteLine("Server says: {0}", serverMessage);

messsage = Encoding.UTF8.GetBytes("exit");
     sslStream.Write(messsage);
     sslStream.Flush();

// Close the client connection.
     client.Close();
     Console.WriteLine("Client closed.");
   }

static string ReadMessage(SslStream sslStream)
   {
     // Read the message sent by the server.
     // The end of the message is signaled using the
     // "<EOF>" marker.
     byte[] buffer = new byte[2048];
     StringBuilder messageData = new StringBuilder();
     int bytes = -1;
     do
     {
       bytes = sslStream.Read(buffer, 0, buffer.Length);

// Use Decoder class to convert from bytes to UTF8
       // in case a character spans two buffers.
       Decoder decoder = Encoding.UTF8.GetDecoder();
       char[] chars = new char[decoder.GetCharCount(buffer, 0, bytes)];
       decoder.GetChars(buffer, 0, bytes, chars, 0);
       messageData.Append(chars);
       // Check for EOF.
       if (messageData.ToString().IndexOf("<EOF>") != -1)
       {
         break;
       }
     } while (bytes != 0);

return messageData.ToString();
   }

private static void DisplayUsage()
   {
     Console.WriteLine("To start the client specify:");
     Console.WriteLine("clientSync machineName [serverName]");
     Environment.Exit(1);
   }

public static void Main(string[] args)
   {
     string machineName = null;
     machineName = "192.168.1.25";
     try
     {
       RunClient(machineName);
     }
     catch (Exception ex)
     {
       Console.WriteLine(ex.Message);
     }
     Console.ReadLine();
   }
 }
}
}

来源：https://www.cnblogs.com/tuyile006/p/13341033.html