This is a write-up for the “Password Here Please” reverse engineering challenge from MetaCTF CyberGames 2020, which was worth 325 points.
Challenge statement: I forgot my bank account password! Luckily for me, I wrote a program that checks if my password is correct just in case I forgot which password I used, so this way I don’t lock myself out of my account. Unfortunately, I seem to have lost my password list as well… Could you take a look and see if you can find my password for me? Part 3 requires some math skills. To solve it, think about what is being done by the exponentiation step. Try rewriting the large number in base 257.