FAQ

What is a 'Danish team'?

3 out of 5 team members must either be Danish citizens or residents.

What info do I need to provide to register?

Just an alias and a team e-mail address where we can reach you if your team qualifies for the final.

My team has 37 members. Can we still play?

Yes... by registering (at least) 8 teams. But remember that you *must not* share flags between teams.

I don't have a team. Can I still play?

Yes. Just register a team for yourself. You will not receive bonus points for playing alone, though.

How do I know if my team is qualified for the final?

We will contact you directly on your registered team e-mail address.

ZOMG! Is last year's edition gone?!

Last year's edition can be found here: https://fe-ctf.dk/2022/

What kind of challenges can I expect?

We strive to test players in a wide range of skills. Expect the usual categories: pwnable, reversing, web, crypto, etc.

How many challenges will there be?

Enough. Challenges will be available at the start of the competition and more will be opened progressively. It will *not* be announced beforehand when new challenges are available, nor how many there are in total.

What is the flag format?

flag{ascii range 0x20-0x7e inclusive, except 0x5c and 0x7d}

What kind of scoring do you use?

We use dynamic scoring. In FE-CTF each challenge belongs to a "series". Each card on the challenge board represents a series. A series can have a single challenge in it. Score calculation is as follows. Let

$P = 1'000'000$: be the total number of points distributed across all teams (except maybe a few lost to rounding).
$D = 0.99$: be a constant determining by how much points decay for each subsequent solve.
$T$: be the set of all teams.
$S$: be the set of series with at least one challenge solved by at least one team.
$C(s)$: be the set of challenges in series $s$ solved by at least one team.
$R(t, c)$: be the ranking of team $t$ for challenge $c$ : $0$ if $t$ got first blood, $1$ if they solved $c$ second, etc., until $\infty$ if team $t$ did not solve challenge $c$ .
$p(x)$: be team $x$ 's total score.

Where

p

is defined as:

$p(x) = \sum_{s \in S, c \in C(s)} \left\lfloor \frac{P}{|S| \cdot |C(s)|} \cdot \frac{D^{R(x, c)}} {\sum_{t \in T} D^{R(t, c)}} \right\rfloor$

I have a question which is not in the FAQ.

That is not really a question. But you're welcome to contact us with your question.

Is the event listed on CTFtime?

Yes and no. The qualifier is listed on CTFtime, but the final will *not* be listed, since it is only open to Danish teams.

Will you install a root kit on my computer if I play?

No. We will not release challenges containing malware.

Will I need real world 0-days to solve some of the challenges?

No. Some challenges *may* require real world exploits, but in those instances the vulnerablity(/ies) will be public knowledge.

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FAQ