Connaître ses tables 2/2

Description

Benoît Blanc thinks he’s managed to hide his AES key in tables.

He provides you with the code written in C to use them, for example:

$ make
$ ./wb-aes keys.bin < /dev/zero
a53c3200a5c8ba9c134016e744dacf5c

In addition, a table for the following key is provided in the key-public.bin file:

8e 73 b0 f7 da 0e 64 52 c8 10 f3 2b
80 90 79 e5 62 f8 ea d2 52 2c 6b 7b

He encrypted the flag using the SHA256 of this key (see output.txt):

def encrypt(k, flag):
    import hashlib
    from Crypto.Cipher import AES
    hk = hashlib.sha256(k).digest()
    E = AES.new(hk, AES.MODE_GCM)
    iv = E.nonce
    c = E.encrypt(flag)
    return {"c": c.hex(), "iv": iv.hex()}