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 💜 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 $\{(u^2 + \varepsilon) \pmod{n} : u \in T \setminus S, \varepsilon \in \{0, 1\}\}$....

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’s blog....

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

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

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

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....

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

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

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

Because there are not many Crypto listed in the "Stock Market", our Cryptotrader Cryptanalyst Mystiz joined us for bounty hunting in Web as well, and we got all Web challenges done this time....