/tags/aes/Recent content in AES onHugo -- gohugo.ioThu, 17 Jul 2025 17:57:16 +0100/post/sr25-puppet/Thu, 17 Jul 2025 17:57:16 +0100/post/sr25-puppet/Click to expand challenge code import os import secrets import sys import time from Crypto.Cipher import AES from Crypto.Util.Padding import pad, unpad SERVER_KEY = secrets.token_bytes(16) FLAG = os.environ.get("FLAG", "FL1TZ{????????????}") def issue_token(user_id: str) -> bytes: iv = secrets.token_bytes(16) payload = f"uid={user_id}&role=puppet".encode() cipher = AES.new(SERVER_KEY, AES.MODE_CBC, iv=iv) return iv + cipher.encrypt(pad(payload,16)) def check_token(token: bytes) -> str: iv = token[:16] ct = token[16:] cipher = AES.new(SERVER_KEY, AES.MODE_CBC, iv=iv) pt = cipher.decrypt(ct) print(f"Decrypted token: {pt!