Broken One-time pad 2

#!/usr/bin/env python3
# vim: set fenc=utf8 ts=4 sw=4 et :
import sys
import socket
import random

from threading import Thread

with open("key.png", "rb") as f:
    SECRET = f.read()

def client_thread(clientsocket):
    clientsocket.send(bytes([
        SECRET[i] ^ random.getrandbits(8)
        for i in range(len(SECRET))
    ]))
    clientsocket.close()

def main():
    serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    serversocket.bind((socket.gethostname(), 8889))
    serversocket.listen()
    print('len(SECRET) = {} Bytes'.format(len(SECRET)))
    sys.stdout.flush()
    while True:
        # accept connections on socket
        (clientsocket, address) = serversocket.accept()
        print('Client connected {}'.format(address))
        sys.stdout.flush()
        thread = Thread(target = client_thread, args = (clientsocket, ))
        thread.start()

if __name__ == "__main__":
    main()