验证链接合法性(hmac)

一种类似于哈希的加密方式，

服务端建立连接后发送固定的随机数，客户端接收同样的随机数后，

使用这串字符串与客户端的密匙生成hmac数据返回服务端，

服务端自己也用hmac把随机数与服务端密匙生成数据

两个数据用hmac模块的比较即可。

服务端

import hmac,os
from socket import *

secret_key = b'just do it'

def conn_auth(conn):
    print('开始验证链接合法性')
    msg = os.urandom(32)
    conn.sendall(msg)
    h = hmac.new(secret_key,msg)
    digest = h.digest()
    respone = conn.recv(len(digest))
    return hmac.compare_digest(respone,digest)


def data_handler(conn,bufsize):
    if not conn_auth(conn):
        print('该链接不合法，关闭')
        conn.close()
        return
    print('链接合法，开始通信')
    while True:
        data = conn.recv(bufsize)
        if not data:break
        conn.sendall(data.upper())


def server_handlse(ip_port,bufsize,backlog=5):
    tcp_socket_server = socket(AF_INET,SOCK_STREAM)
    tcp_socket_server.bind(ip_port)
    tcp_socket_server.listen(backlog)
    while 1:
        conn,addr = tcp_socket_server.accept()
        print('产生新连接')
        data_handler(conn,bufsize)

if __name__ == '__main__':
    ip_port = ('121.195.167.34',9999)
    bufsize = 1024
    server_handlse(ip_port,bufsize)

客户端

import hmac
from socket import *

secret_key = 'just do it'.encode('utf-8')

def conn_auth(conn):
    msg = conn.recv(32)
    h = hmac.new(secret_key,msg)
    digest = h.digest()
    conn.sendall(digest)



def client_handler(ip_port, bufsize):
    tcp_socket_client = socket(AF_INET,SOCK_STREAM)
    tcp_socket_client.connect(ip_port)

    conn_auth(tcp_socket_client)

    while True:
        data = input('>>>:').strip()
        if data == 'quit':
            break
        else:
            continue
        tcp_socket_client.sendall(data.encode('utf-8'))
        respone = tcp_socket_client.recv(bufsize)
        print(respone.decode('utf-8'))
    tcp_socket_client.close()

if __name__ == '__main__':
    ip_port = ('121.195.167.34',9999)
    bufsize = 1024
    client_handler(ip_port,bufsize)

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