## Bauhinia CTF 2023: Image Factory

Last year, I created a pwn challenge for the Bauhinia CTF competition. Personally, I consider it to be the most difficult pwn challenge I have ever created, and here I would like to share the challenge and its intended solution. At the same time, I will discuss common solving approaches you may find useful for this type of challenge. Overview As a CTFer, we have the obligation to code any program in a secure manner, even if a university assignment, right?...

March 10, 2024 路 cire meat pop

## CryptoCTF 2023 Writeup

Welcome!! (23 points, 663 solves) Difficulty: Warm-up We surely did get warmed up this CTF, as we came second, even beating the Cryptohackers (merge) team! Well done to everyone who participated 馃挏 Did it! (33 points, 220 solves) Difficulty: Easy The parameters $n = 127$ and $\ell = 20$ is fixed. A hidden subset of $\ell$ numbers $S \subseteq \{0, 1, \cdots, n - 1\}$ with $|S| \leq \ell$ is chosen, and we are given $13$ calls to the following oracle: Given a set $T \subseteq {0, 1, \cdots, n - 1}$ also with $|T| \leq \ell$, the server computes $T \setminus S$ and outputs $\{(u^2 + \varepsilon) \pmod{n} : u \in T \setminus S, \varepsilon \in \{0, 1\}\}$....

August 28, 2023 路 grhkm, nhho, TWY

## HKCERT CTF 2022 Making-of: Minecraft Geoguessr

One challenge we wrote for HKCERT CTF 2022 is Minecraft Geoguessr. In this blog post, we will talk about stuffs behind the scene, including how the challenge was created and the lessons learnt. If you are interested in the solution, please refer to @mystiz鈥檚 blog....

April 5, 2023 路 apple, mystiz

## LA CTF 2023 Writeup

Our collection of writeups for LA CTF 2023....

February 26, 2023 路 a1668k, botton, cire meat pop, fsharp, J4cky, LifeIsHard, Kaiziron, RaccoonNinja

## idekCTF 2022* Writeup

Our collection of writeups for idekCTF 2022*....

February 3, 2023 路 botton, cire meat pop, fsharp, harrier, Hollow, J4cky, Kaiziron, LifeIsHard, Mystiz, ozetta, RaccoonNinja, TWY

## ASIS CTF 2022 Finals Writeup

Our collection of writeups for ASIS CTF 2022....

January 10, 2023 路 fsharp, grhkm, harrier, LifeIsHard, Mystiz, Viky

## TetCTF 2023: pwn01

I did not solve it in time (30 minutes late T.T). However, I spent quite of lot of time on this challenge, so I might as well do a write up. Special thanks to Mystiz, fsharp, cire meat pop for helping me on this challenge....

January 9, 2023 路 Viky

## BackdoorCTF 2022 Writeup

We played BackdoorCTF and we won the second place....

December 24, 2022 路 botton, fsharp, harrier, LifeIsHard, J4cky, Ja5on, Mystiz, Viky

## BSides Mumbai CTF 2022 Writeup

We played BSides Mumbai CTF 2022 last week and we got the third. This is the write-up on the challenges we solved....

December 14, 2022 路 cire meat pop, fsharp, grhkm, Hollow, Ja5on, LifeIsHard, Kaiziron, Mystiz, TWY

## TSJ CTF 2022 Writeup

We played TSJ CTF last weekend and we won! This is the writeups of our challenges...

March 5, 2022 路 grhkm, harrier, Mystiz, ozetta