To Be XOR Not To Be

Problem

You find 2 weird files, maybe https://en.wikipedia.org/wiki/Exclusive_or will help.

Solution

A simple XOR between the key string and the ciphertext. We need to convert key to an integer before performing the XOR. After the XOR, we need to convert the result back into a bytestring to get our flag.

from Crypto.Util.number import long_to_bytes, bytes_to_long

c = 0b101010101001101010001000100001101010100010001100010110101111011011101110011001100011000000010110101100100011110000100110011011000000111000100000010101100001011000101110101100100011011000100010100100101011100
key = "this is the key!"

print(long_to_bytes(bytes_to_long(key.encode()) ^ c))