Google CTF 2025 Quals Writeup
I wrote two challenges for Google CTF qualifier - Underhanded and Merkurated. There were 17 and 37 solves during the contest time. I will cover both in this blog post.
Read More →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.
Read More →Google CTF 2023: MHK2
MHK2 is one of the challenges I coauthored for Google CTF 2023 and there were 18 teams solving this challenge during the contest time.
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