Real quick step away from the RSA series. I just put in an application for Ubuntu and I want to make sure I have at least one something here about reversing in case they check out my site. ::prayer hands::
I like to use crackmes.one to get publicly available crack-mes. This particular file can be found there and is called timotei crackme#1. The solution you can find on the site is actually this solution. It appears that I am, to date, the only one who has submitted an acceptable solution.
I expect this is because it uses a custom rolled hash function that clobbers information we need to actually reverse the algorithm used. Which leaves us with brute force or OSINT to obtain the answer.
On the other hand, there is a pin that needs to be obtained as well. And, despite it’s use of modulo division, there are several ways to crack it to obtain a valid pin