import os

from Crypto.Cipher import AES
from Crypto.Hash import Poly1305

FLAG = os.getenv("FLAG", "Alpaca{dummy}")
TARGET = b"admin=true"

KEY = os.urandom(32)
NONCE = os.urandom(16)

def mac(message):
    return Poly1305.new(key=KEY, cipher=AES, nonce=NONCE, data=message).hexdigest()

for _ in range(2):
    message = input("message: ").encode()
    if not message or message == TARGET:
        raise SystemExit("invalid message")
    print(mac(message))

if input("tag: ") == mac(TARGET):
    print(FLAG)
else:
    print("invalid")