/tags/ecc/Recent content in ECC onHugo -- gohugo.ioThu, 17 Jul 2025 19:31:16 +0100/post/sr25-lights/Thu, 17 Jul 2025 19:31:16 +0100/post/sr25-lights/Click to expand challenge code from hashlib import sha256 from Crypto.Util.number import bytes_to_long, long_to_bytes from random import randint from Crypto.Cipher import AES from Crypto.Util.Padding import pad import json FLAG = b"FL1TZ{??????????????????????????}" p = 0xa9fb57dba1eea9bc3e660a909d838d726e3bf623d52620282013481d1f6e5377 a = -3 b = 27 E = EllipticCurve(GF(p), [a,b]) G = E.gens()[0] j = E.j_invariant() def gen_random_number(): while True: P = E.random_point() if P.order() > j: break return bytes_to_long(sha256(long_to_bytes(int(P.xy()[0]))).digest()[:8]) def derive_key_iv(secret): key = sha256(long_to_bytes(secret)).