Secure-Chatroom-using-DES-Algorithm/socket_client.py at main · AmDevamithra/Secure-Chatroom-using-DES-Algorithm · GitHub

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import socket

from threading import Thread
import des


HEADER_LENGTH = 128

client_socket = None


my_key = des.generate_keys()[0]  #  DES uses symmetric key

def connect(ip, port, my_username, error_callback):

    global client_socket


    client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)


    try:

        client_socket.connect((ip, port))

    except Exception as e:

        error_callback('Connection error: {}'.format(str(e)))

        return False


    username = my_username.encode('utf-8')

    username_header = f"{len(username):<{HEADER_LENGTH}}".encode('utf-8')

    client_socket.send(username_header + username)


    # Send DES key

    key = repr(my_key).encode('utf-8')

    key_header = f"{len(key):<{HEADER_LENGTH}}".encode('utf-8')

    client_socket.send(key_header + key)


    return True


def send(message, user):

    print(f'\nOriginal message: \n{message}\n')

    cipher = des.encrypt(message, user['key'])

    print(f'\nEncrypted message: \n{cipher}\n')

    message = (cipher + ':>>>:' + user['user']).encode('utf-8')

    message_header = f"{len(message):<{HEADER_LENGTH}}".encode('utf-8')

    client_socket.send(message_header + message)


def start_listening(incoming_message_callback, error_callback):

    Thread(target=listen, args=(incoming_message_callback, error_callback), daemon=True).start()


def listen(incoming_message_callback, error_callback):

    global my_key

    while True:

        try:

            while True:

                new_header = client_socket.recv(HEADER_LENGTH)

                if not len(new_header):

                    error_callback('Connection closed by the server')

                username_length = int(new_header.decode('utf-8').strip())

                username = client_socket.recv(username_length).decode('utf-8')

                message_header = client_socket.recv(HEADER_LENGTH)

                message_length = int(message_header.decode('utf-8').strip())


                if username != '__flag__':

                    cipher = client_socket.recv(message_length).decode('utf-8')

                    print(f'\nReceived encrypted message: \n{cipher}\n')

                    decrypted_message = des.decrypt(cipher, my_key)

                    print(f'\nDecrypted message: \n{decrypted_message}\n')

                    message = decrypted_message

                else:

                    message = client_socket.recv(message_length).decode('utf-8')


                incoming_message_callback(username, message)


        except Exception as e:

            print(f"Error details: {str(e)}")  # Add detailed error logging

            error_callback('Reading error: {}'.format(str(e)))