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UDP User Authentication

G5 Cyber Security

TL;DR

This guide shows you how to authenticate a user using UDP sockets in Python. It’s less secure than TCP but faster for simple checks where data loss isn’t critical. We’ll cover setting up the server, handling client requests, and verifying credentials.

Setting Up The Server

  1. Import necessary libraries: You’ll need the socket library to work with UDP sockets.
  2. Create a UDP socket: Use socket.socket(socket.AF_INET, socket.SOCK_DGRAM). AF_INET specifies IPv4 addressing, and SOCK_DGRAM indicates a UDP socket.
  3. Bind the socket to an address and port: This tells the operating system where to listen for incoming connections. Choose a port number above 1023 (ports below are usually reserved).
import socket

socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
bind_address = ('localhost', 5000) # Example address and port
socket.bind(bind_address)
print('UDP server listening on {}:{}'.format(*bind_address))

Handling Client Requests

  1. Receive data: Use socket.recvfrom(buffer_size) to receive data from clients. This returns a tuple containing the data and the client’s address.
  2. Decode the message: The received data is in bytes, so decode it using .decode('utf-8') (or another appropriate encoding).
  3. Process the authentication request: Extract the username and password from the decoded message. You’ll need to define a clear message format (e.g., comma-separated values).
  4. Verify credentials: Check if the provided username and password match your stored user data. Important: Never store passwords in plain text! Use hashing algorithms like bcrypt or Argon2.
  5. Send a response: Send an appropriate response back to the client indicating success or failure. Encode the message using .encode('utf-8') before sending it with socket.sendto().
buffer_size = 1024
data, address = socket.recvfrom(buffer_size)
messages = data.decode('utf-8').split(',')
username = messages[0]
password = messages[1]

# Replace with your actual authentication logic (e.g., database lookup)
if username == 'user' and password == 'password':
    response = 'Authentication successful'.encode('utf-8')
els:
    response = 'Authentication failed'.encode('utf-8')

socket.sendto(response, address)

Client Implementation

  1. Create a UDP socket: Similar to the server.
  2. Send data: Encode your username and password into a message (e.g., comma-separated) using .encode('utf-8'), then send it to the server’s address and port with socket.sendto().
  3. Receive response: Use socket.recvfrom(buffer_size) to receive the server’s response.
  4. Decode the response: Decode the received bytes using .decode('utf-8').
import socket

socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
server_address = ('localhost', 5000)
message = 'user,password'.encode('utf-8') # Example message
socket.sendto(message, server_address)
data, address = socket.recvfrom(buffer_size)
response = data.decode('utf-8')
print('Server response:', response)

Important Considerations

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