dJulkalendern 2023

dChristmasy greetings D chapter!

It is once again time for Konglig Datasektionen’s yearly CTF competition dJulkalendern! Do you have too much time to study? Exams to procrastinate for? Chapter-work to do some other time? Wonderful! Come and compete for the title Bäst på att DATA™!

A challenge is released every weekday in December (starting this friday!!!) before christmas eve at 12:15 CET. The challenges are cryptic puzzles, hacking and other computer science related things and your task is to solve as many of them, and as fast, as possible! The calendar has an intriguing story that unfolds as you solve each window.

The competition is individual, but a little while after a window has been released it is both allowed and encouraged to cooperate!

The winner receives the title Bäst på att DATA™. There is also an achievement patch for those who solve all windows and those who do it the quickest will receive dJulkalendern-themed T-shirts!

You can now already go to and solve the introductory window, -1, as well as make sure you understand the system and read the rules!

You should also join our discord server:, where you can ask us questions, discuss the windows you have solved and be notified about any possible hints!

Regards, Tomtefar Mathias Magnusson and the rest of the dJul team!