SECCON 2018 Online CTF Special Instructions

special_instructions

#!/usr/bin/env python


def main():
    key = ["35c36d03",
           "c8fa2132",
           "9f72275c",
           "3ed1ca90",
           "e32b4951",
           "1c29ac51",
           "e5e39880",
           "7f0f53f9",
           "89d0b941",
           "f5e6563d",
           "cbf769ad",
           "4ba4dacc",
           "49a432b2",
           "c557954b",
           "40a4eeb4",
           "dd74800d",
           "ce2e86b7",
           "2a1de9cb",
           "f6084259",
           "70ff1d78",
           "b93854d0",
           "b5228d01",
           "8b22df40",
           "8b583725",
           "e54151fb",
           "e45c5644",
           "1e13e10e",
           "6a399017",
           "f63e5c0a",
           "bcd582d5",
           "9ec62492",
           "7e8849b8"]

    flag = "6d 72 c3 e2 cf 95 54 9d b6 ac 03 84 c3 c2 35 93 c3 d7 7c e2 dd d4 ac 5e 99 c9 a5 34 de 06 4e".split(" ")

    randval = "3d 05 dc 31 d1 8a af 29 96 fa cb 1b 01 ec e2 f7 15 70 6c f4 7e a1 9e 0e 01 f9 c2 4c ba a0 a1 08".split(" ")
    result = ""

    for i in range(len(flag)):
            result += chr((int(randval[i], 16) ^ int(key[i][-2:], 16)) ^ int(flag[i], 16))

    print result


if __name__ == "__main__":
    main()