一、说明

1. python标准库ssl可实现加密通信

2. ssl库底层使用openssl，做了面向对像化改造和简化，但还是可以明显看出openssl的痕迹

3. 本文先给出python实现的socket通信，在此基础上再给出ssl通信以便读者更方便地看到socket和ssl在python编程中的区别

4. 说到ssl很多人都会想到https，但本质而言ssl是在传输层和应用层之间新插入的一个层，根据不同层无关原则ssl和https并没有任何绑定关系，ssl之上完全可以是其他任何应用层协议（比如pop/imap/telnet等等）

二、程序实现
2.1 socket通信实现
客户端代码：

import socket

class client_class:
    def send_hello(self):
        # 与服务端建立连接
        client_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
        client_socket.connect(('127.0.0.1',9999))

        # 向服务端发送消息
        msg = "do i connect with server ?".encode("utf-8")
        client_socket.send(msg)
        # 接收服务端返回的消息
        msg = client_socket.recv(1024).decode('utf-8')
        print(f"receive msg from server : {msg}")
        client_socket.close()

if __name__ == "__main__":
    client = client_class()
    client.send_hello()

服务端代码：

import socket

class server_class :
    def build_listen(self):
        # 监听端口
        server_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
        server_socket.bind(('127.0.0.1',9999))
        server_socket.listen(5)

        while True:
            # 接收客户端连接
            client_socket, addr = server_socket.accept()
            # 接收客户端信息
            msg = client_socket.recv(1024).decode("utf-8")
            print(f"receive msg from client {addr}：{msg}")
            # 向客户端发送信息
            msg = f"yes , you have client_socketect with server.\r\n".encode("utf-8")
            client_socket.send(msg)
            client_socket.close()

if __name__ == "__main__":
    server = server_class()
    server.build_listen()

2.2 ssl通信实现
客户端代码：

import socket
import ssl

class client_ssl:
    def send_hello(self,):
        # 生成SSL上下文
        context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
        # 加载信任根证书
        context.load_verify_locations('cert/ca.crt')

        # 与服务端建立socket连接
        with socket.create_connection(('127.0.0.1', 9443)) as sock:
            # 将socket打包成SSL socket，其主要工作是完成密钥协商
            # 一定要注意的是这里的server_hostname不是指服务端IP，而是指服务端证书中设置的CN，我这里正好设置成127.0.1而已
            with context.wrap_socket(sock, server_hostname='127.0.0.1') as ssock:
                # 向服务端发送信息
                msg = "do i connect with server ?".encode("utf-8")
                ssock.send(msg)
                # 接收服务端返回的信息
                msg = ssock.recv(1024).decode("utf-8")
                print(f"receive msg from server : {msg}")
                ssock.close()

if __name__ == "__main__":
    client = client_ssl()
    client.send_hello()

服务端代码：

import socket
import ssl

class server_ssl:
    def build_listen(self):
        # 生成SSL上下文
        context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
        # 加载服务器所用证书和私钥
        context.load_cert_chain('cert/server.crt', 'cert/server_rsa_private.pem.unsecure')

        # 监听端口
        with socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0) as sock:
            sock.bind(('127.0.0.1', 9443))
            sock.listen(5)
            # 将socket打包成SSL socket，其主要工作是完成密钥协商
            with context.wrap_socket(sock, server_side=True) as ssock:
                while True:
                    # 接收客户端连接
                    client_socket, addr = ssock.accept()
                    # 接收客户端信息
                    msg = client_socket.recv(1024).decode("utf-8")
                    print(f"receive msg from client {addr}：{msg}")
                    # 向客户端发送信息
                    msg = f"yes , you have client_socketect with server.\r\n".encode("utf-8")
                    client_socket.send(msg)
                    client_socket.close()

if __name__ == "__main__":
    server = server_ssl()
    server.build_listen()

三、运行结果
当前项目结构如图所示，证书生成可参考：openssl实现双向认证教程（服务端代码+客户端代码+证书生成）