After finishing a hard lesson in geometry class, Keith decided that he wanted to put your understanding of trig and python to the test. Can you solve his challenge?
We are given trig_is_really_hard.py, which is basically a custom hashing algorithm.
This hashing algorithm output depend on the length on the input, more specifically, 2+3+...+(n+1)=n(n+3)/2
The program ‘hashes’ our input, then compare with a preexisting hash.
Playing around with this, we notice that any changes to the plaintext will only affect the characters afterwards, so all the digits that have been generate remain untouched.
The length of the hash is 90, thus the length of our solution is either -15 or 12. -15 seems a bit hard to achieve so we’ll assume n=12
Now we simply bruteforce each character, ensuring that the length remains at 12 and start matching more and more of the given hash.
Flag:
hsctf{:hyperthonk:}