The Hidden Room

While at Kinglecon, I discovered a hidden room! Right here, behind the booths outside in the courtyard, there is a little spot to enter:

Which lead to a new little area!

A single character sitting behind a booth. Clicking on him shows...really garbled text:

Really bizarre stuff. But there was another weird attribute here...if I typed anything in the chat window, it showed up as garbled text as well! Simply typing "Hello there" returned something like "83sso/t8303". This seemed like a job for cyberchef!

Messing with the chat showed that I had access to the encryption cipher, and that if I were to repeat letters, their counterparts to this encryption method would also get repeated. So if I were to type AAAAAA, it would return 888888. This was a pretty straightforward substitution cipher! Could be ROT13, but it didn't seem that rudimentary. I had a crib I could use, in this case it would be the full alphabet and the resulting ciphertext, and I could plug them both into cyberchef using the substitution recipe:

As you can see, if I send a crib to the encryption oracle of something like ABCDEFGHIJKLMNOPQRSTUVWXYZ? abcdefghijklmnop... etc, I can take the resulting ciphertext and plug that in as the ciphertext in the substition recipe, take the resulting output of that and simply type that into the chat. Doing so meant I could text garbled nonsense and it would come out as plain english in the chat, as evidenced as the above screenshot!

Now I could just reverse the above, click on the booth guy a bunch of times and record what they said, then simply dump it into cyberchef:

He keeps repeating "I'm Evan Booth", "Its the ooth" or something. Okay! Evan Booth works for Counterhack!