Not the Flag

Challenge

We receive a hex string described as “not the flag”.

Approach

The challenge name and description hint heavily at bitwise NOT. XOR each byte with 0xFF:

1
2
3

ct = bytes.fromhex("cb ce ce ce ...")  # given hex (spaces stripped)
flag = bytes(~b & 0xFF for b in ct)
print(flag.decode())

Flag

boroCTF{th1$_is_n0t_not_th3_fl@g}