Google CTF 2024 (III): IDEA
IDEA is a challenge written by @0xdeuterium. He even provided me the paper to refer, my only contribution to the challenge is to optimize the original solution so that we don’t need 65K-ish oracle calls.
Read More →Google CTF 2024 (II): ZKPOK
ZKPOK is a challenge I made while learning Zero Knowledge Proofs on zk-learning.org. I was watching the first lecture video, I came across with the interactive proof for quadratic residues at 20:00. This made me ponder - it should be easy to apply Fiat-Shamir transform to make this non-interactive. Let’s also use MD5 so that it could be vulnerable. Hours later, this challenge appeared without a proper solve script.
Read More →Google CTF 2024 (I): Blinders
This is yet another edition of Google CTF, where I wrote some crypto challenges with my colleagues. I contributed on three challenges this time, namely, Blinders, ZKPOK and IDEA. There are respectively 56, 3 and 4 solves (out of 267 teams scoring non-zero flags) during the contest period. Blinders is one of the challenges I coauthored, which introduces a protocol for private set membership.
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HKCERT CTF 2023 Postmortem (III): The Remaining Challenges
We will finally cover the non-crypto challenges that I wrote for HKCERT CTF 2023. This includes one misc (Hackforces), two pwn (ISA Jump Scare & ISA Jogger) and two reverse (The Flag Game & Loot and Scoot) challenges.
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HKCERT CTF 2023 Postmortem (II): Harder Crypto Challenges
In the second part of the series, I will cover four cryptography challenges: baDES, Maybe Someday, Cipher Bridging Service and RSA Triooo. Interestingly, most of them are somehow "plagiarized" from the other CTFs.
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