This year my team c0d3_h4cki05_ got the opportunity to host BSides Delhi CTF. We organized the CTF on October 10th which is a 10 hour CTF (13.00 - 22.00 IST). Also this is a begginer friendly CTF. I’m happy that it went well. Yay! I authored three challenges for this CTF which are of difficulty ranging from easy, medium and hard. This blog post is to cover the intended solutions to all the 3 crypto challenges....
First things first, Arab Security Cyber Wargames is a qualifiers CTF, Top 10 would be qualified for the finals at Egypt. We c0d3_h4cki05_(aka bi0s|Bangalore) finished 10th globally, hence we qualified for finals! Yay! In this blog post I will be discussing 2 crypto challenges from Arab Security Wargames CTF Quals. As there were some glitches with the server initially, they shared the challenges repo in the discord server, so we were able to work on the challenges even though there were some glitches....
Challenge: PolyRSA Description All the warmup you need Writeup Given out.txt which consists of p n (as polynomial) m^65537 (ciphertext also as polynomial) To be honest, I never solved an RSA challenge based polynomials. So I checked for similar challenges which I couldn’t find, but I found one research paper from which I was able to solve this challenge. It is just similar to integer RSA, instead of numbers we have here polynomials....