first_stage.py

import socket
import time

seed = open('seed', 'rb').read()
count_max = 0xf81000 - 0x20

def calc4(buf, arg2):
    
    res = 0
    for arg3 in range(4):
        res |= calc(buf, arg2, arg3)

    return res

def calc(buf, arg2, arg3):
    shift = arg2 >> 3
    w = arg2 & 7

    v1 = ord(buf[shift + arg3])
    esi = v1 << w

    v2 = ord(buf[shift + arg3 + 1])
    edx = v2 >> (8 - w)

    eax = (esi | edx) & 0xff
    eax = eax << [24, 16, 8, 0][arg3]

    return eax

def unloop(id):

    i = id / 4
    j = id % 4
    count1 = i / count_max
    count2 = i % count_max

    result = calc4(seed, count1) ^ calc4(seed, count2)
    return (result >> [24, 16, 8, 0][j]) & 0xff

def fix(x):
    eax = x
    ecx = x
    edx = x

    eax = eax * 3
    eax = eax << 5
    eax = eax + ecx
    eax = eax >> 8

    ecx = ecx - eax
    ecx = ecx >> 2
    eax = eax + ecx
    eax = eax >> 6
    ecx = 0x5d
    eax = eax * ecx
    edx = edx - eax
    eax = edx & 0xff
    eax = eax + 0x20

    return eax & 0xff

HOST = '100lines_53ac15fc7aa93da92629d37a669e106c.2014.shallweplayaga.me'
PORT = 20689

# Connect
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
s.settimeout(2)

otp = []
otp.append(int(s.recv(1024).split("\n")[1], 16))
map(lambda x: otp.append(x), map(lambda x: int(x, 16), s.recv(1024).strip().split(" ")))

payload = ""
for x in otp:
    print x, unloop(x), fix(unloop(x))
    res = fix(unloop(x))
    payload += chr(res)

s.send(payload)

print s.recv(1024)
print s.recv(1024)