For this question, your goal is to find a hash collision.
We've defined a bad hash function,
which is using counter mode to encrypt
and then XORing all the blocks of cipher text that come out
and using that as the hash output.
And we've provided the code for our hash function.
Your goal is to find 2 strings where the hash outputs are the same
but the actual strings are different.
For this problem, we've provided an implementation of counter mode
to be used as a hash function.
The counter mode will take in a plaintext input
and calculate the cipher blocks as expected,
which are then XORed together to return the hash.
Your job will be to implement findcollision
to find a collision given an input message.
We've provided 4 test cases for you to use
to see if your code works
along with some  utility functions that you might find useful.
