I could not participate in GiS CTF which was conducted around 10 days back. But, the one good thing about these people is that they always have an archive of all their past events. This is a 150 point Crypto challenge named as Knockers. Here is the question. Dude, here’s a knocker token that will let you access my service on port 80. One day I will let you see my cool stuff on port 7175.