I prepared three challenges on behalf of @blackb6a for MOCSCTF, which is a 8-hour long CTF happened yesterday. This blogpost serves as the write-up for the three challenges that I wrote.

There are two solves (out of 40 participants) for Three-pass, and zero solves for jav-asr-ipt and Catch-22 Mini.

Like in 2021 and 2022, I contributed some challenges for Firebird’s internal CTF, which are from the Hong Kong University of Science and Technology. This time I wrote three crypto challenges: Randomsum, Shelter and Threerider.

There were 24 teams participating. There were three solves for Randomsum, while Shelter and Threerider were unsolved during the CTF.

2022 is a life-changer for me. There were some tough decisions and a few surprises.

In the last part, I will include the two non-crypto challenges I wrote for HKCERT CTF 2022: Numbers go brrr and Minecraft geoguessr.

We will continue walking through the remaining crypto challenges I wrote for HKCERT CTF 2022: Mystiz can’t code, Slow keystream and King of Rock, Paper, Scissors.