On May 1st we (polygl0ts) held the LakeCTF finals in Lausanne (at EPFL). It was a blast!
I had just become president of polygl0ts in January 2026, and without having much CTF organizational experience, this was a big bite to chew! I have some challenge authoring experience as I made a couple of pwn challenges for the Serbian ECSC quals, but have never really been involved in the event organization and tech infrastructure side of things.
I haven’t been in polygl0ts for that long (joined in the second half of 2025) either, so this was a huuuuuuge learning curve. Lots of the currently active polygl0ts committee is relatively fresh as well, so it was a bit of a struggle, but we managed to swim out with the help of therokdaba, cyanpencil, and EPFL IC-COM.
In the end the event was a great success, and I think most players had lots of fun too. I wrote a ton of docs for polygl0ts on how to organize this event, so hopefully next year is not as much of a scramble xd .
Challenge Authoring
Challenge authoring was a roller coaster.
Regarding my own challenges: thanks P.Howe for pushing for the making of stardew-valley, I don’t know if I would’ve had the courage to sink so much time into something which I’m unsure if a good challenge can come out of it, but in the end it was a really good learning experience, and a good challenge did come out of it!
I’m also relatively happy with how gun turned out, and in general I really like seeing how players solve more open-ended challenges (doubly true for fihing!).
I really wanted to be on top of all of the challenges to make sure everything makes sense. We have lots of really experienced people, but also lots of newish authors (important for the growth of the team as well!). That being said I was surprised at how unqualified I felt to appraise some of the challenges, which probably should have been obvious - I’ve only ever touched pwn - how can I appraise a crypto / web / misc? Misc is especially troublesome, and the most common cause of frustration for players. I often found myself asking “what kind of challenges do misc mains even like?”.
Nevertheless with a lot of help from cyanpencil and the more experienced authors, I think we got to a pretty decent place. I wish we had set up a feedback form type of thing though, rather than only rely on getting the players’ impressions by talking to them IRL - I mostly talked about the pwn and some challenges were left underdiscussed depending on how social the author was ;; .
The onsite challenges were quite a success too, I loved seeing people jump up and down after beating us in Tekken. We will probably look to do something similar again next year, though I would maybe look to make them a bit easier / faster so as not to undermine the competitive aspect of the CTF too much. Someone should be able to just zero in on the “normal” challenges. The onsite stuff is more meant to give you an outlet to take a break and have some fun.
Finally I’m really glad Robin_Jadoul and killerdog made it to the finals. Robin has been a LakeCTF author for years, but this is his first time attending in person. And killerdog wanted to come as an emissary for Zellic, so we pitched him to become an author! CTFs have been slacking on this idea, if a company primarily made of CTF players sponsors you, why not cop someone from there to author a challenge? Hope to see you both next year too!
Small Incomprehensible Representations
The no-LLM ruling was a great success! I’ll even say, about an hour into the competition, no challenges were solved yet, we were getting a bit scared that we messed the deployment up or something. It was a bit weird having to wait so long after getting used to the recent slopfests of challenges getting cleared in the first five minutes.
It’s a bit of a shame that CTFs are likely to stray away from real word security research, but it is what it is. Onsite CTFs will at least survive! In all likelyhood, we will have the same ruling next year as well. Not sure what to do for quals though. Maybe we make them invite only?
Themeing
I think meow suggested that we theme the CTF some way this year. This was great. The theme suggestion (Serial Experiments Lain) was by yours truly. For sure we want to pick a theme as well next year, it’s just so much fun.
Huge thanks to cyanpencil for designing the CTFd frontend, it looks insanely cool. I just want to leave a few screenies here, I honestly can’t get enough of it.
Conclusion
(the lakectf-24-25 discord channel on the polygl0ts discord)
heh. Not on my watch. cyan - you’re hosting a demoparty for the 5 year anniversary you hear?