"""
EXAMPLE: Pwn2Win 2021 — "A2S" (Crypto, 355p, 10 solves)
https://github.com/p4-team/ctf/tree/master/2021-05-28-pwn2win/a2s

VULN: reduced AES (2 rounds). A differential attack (attack.py in this dir)
recovers the equivalent key k from 3 known (plaintext, ciphertext) pairs,
then decrypts the flag with a standard AES-CBC key = sha1(k)[:16].

The original challenge used Python 2 (`str(k)` for the sha1 input). The
canonical solver is attack.py and it prints the flag directly. This wrapper
runs attack.py and extracts the flag so the example stays reproducible.

Run:
    cd /home/code/ctfkit/examples/a2s
    python3 solve.py
Expected flag: CTF-BR{bu7_1f_7h0u6h7_c0rrup75_l4n6u463,_l4n6u463_c4n_4l50_c0rrup7_7h0u6h7}
"""
import os
import re
import subprocess
import sys

HERE = os.path.dirname(os.path.abspath(__file__))


def main():
    out = subprocess.run(
        [sys.executable, os.path.join(HERE, "attack.py")],
        capture_output=True, text=True,
    ).stdout
    m = re.search(r"CTF-BR\{[^}]+\}", out)
    flag = m.group(0) if m else None
    print("FLAG =", flag)
    return flag


if __name__ == "__main__":
    main()