happy monday

import socket

import binascii

def connect_and_get_flag(server_ip, server_port):

    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:

        s.connect((server_ip, server_port))

       

        # Read the welcome message with the encoded flag

        welcome_message = s.recv(1024).decode()

        print("Received:", welcome_message)

       

        # Extract the hex-encoded flag from the welcome message

        encoded_flag = welcome_message.split("flag 1: ")[1].split("\n")[0]

       

        # Known start of the flag

        known_start = "THM{"

       

        # Convert hex to ASCII

        ascii_str = binascii.unhexlify(encoded_flag).decode()

       

        # Derive the key using the known start of the flag

        key = ''.join([chr(ord(c1) ^ ord(c2)) for c1, c2 in zip(known_start, ascii_str[:len(known_start)])])

        print("Derived key:", key)

       

        # Decrypt the entire message using the derived key

        decrypted_message = ''.join([chr(ord(c) ^ ord(key[i % len(key)])) for i, c in enumerate(ascii_str)])

        print("Decrypted message:", decrypted_message)

       

        # Send the derived key back to the server

        s.sendall(key.encode() + b'\n')

       

        # Read the server response with flag 2

        response = s.recv(1024).decode()

        print("Server response:", response)

# Replace with actual server IP and port

server_ip = "10.10.218.175"

server_port = 1337

connect_and_get_flag(server_ip, server_port)