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이번에 CyKor CTF 2025에서 Rock Scissors Paper 문제를 출제하였고 간단히 writeup을 적어보았습니다.chall.pyimport hashlibimport randomimport jsonfrom secret import flagRSP = ['Rock', 'Scissors', 'Paper']HASH_LIST = ['md5', 'sha1', 'sha256']SALT_MAX = 10ROUND = 2000class Alice: def __init__(self): self.rsp_list = [random.choice(RSP) for _ in range(ROUND)] self.hash_choice = [random.choice(HASH_LIST) for _ ..

LG U+ Security Hackaton quals, final 에 나왔던 크립토 문제 writeup 입니다.rsa-signatur3import randomfrom secret import dfrom Crypto.Util.number import bytes_to_longdef signature(N, d, msg): return pow(msg, d, N)N = [ 67577778555166722247402560759016828124494232526088812750031932072809058478849, 57742351689157787483290298402407609974551631306875257923418974388638525690029, 32708033774138713819670853756783..

보호되어 있는 글입니다.

ezpz_cryptofrom Crypto.Cipher import AESfrom Crypto.Util.Padding import padfrom Crypto.Util.number import getPrimefrom math import gcdimport randomclass LCG: def __init__(self, bit_length=32, n=10): self.m = getPrime(bit_length) self.a, self.c, self.m = self._generate_params(self.m) self.seed = random.randint(0, self.m - 1) self.n = n def _generate_params(self, ..