serial_misc50.py

#usr/bin/python

#Faid Mohammed Amine 
#Fb : piratuer

from pwn import *
import sys




def main():
    con = remote('misc.chal.csaw.io', 4239)
    con.recvline()
    while True:
        bins = con.recvline().strip()
        assert bins[0] == '0'
        assert bins[-1] == '1'
        bs = map(int, list(bins))[1:-1]
        pty = bs[-1]
        cs = bs[:-1]
        if cs.count(1) % 2 == pty:
            sys.stdout.write(chr(int(bins[1:-2], 2)))
            con.sendline('1')
        else:
            con.sendline('0')

main()