Implementing-cryptography-using-python

Chapter 7 ■ Message Integrity 213
# Save as server.py
# Message Receiver
import os
from socket import *
host = ""
port = 13000
buf = 1024
addr = (host, port)
UDPSock = socket(AF_INET, SOCK_DGRAM)
UDPSock.bind(addr)
print ("Waiting to receive messages...")
while True:
(data, addr) = UDPSock.recvfrom(buf)
print ("Received message: " + str(data,'utf-8'))
if data == "exit":
break
UDPSock.close()
os._exit(0)
Create a Client Socket
The next Python code will create the client that will send messages to the server
over port 13000. Once the code executes, it will launch a command window
that states Enter message to send or type ‘exit’. Messages entered here will be sent
unencrypted to the server. We will explore how to encrypt and decrypt these
messages using symmetric encryption. Once you complete the following script,
you will be able to send messages from the client to the server, as shown in
Figure 7.4.
# Save as client.py
# Message Sender
import os
from socket import *
host = "127.0.0.1" # set to IP address of target computer
port = 13000
addr = (host, port)
UDPSock = socket(AF_INET, SOCK_DGRAM)
while True:
data = input("Enter message to send or type 'exit': ").encode()
UDPSock.sendto(data, addr)
if data == "exit":
break
UDPSock.close()
os._exit(0)