This time I went to @DeFiHackLabs and attempt my very first Web3-focused CTF. I am fortunately able to solve some challenges. Nothing particular difficult, but that’s still something.

The crypto challenge authors in HITCON 2024, @maple3142 and @_bronson113 prepared a set of exciting and difficult challenges.

I collaborated with @thehackerscrew1 as a guest player this time. In this blog post, we will cover three challenges: ZKPoF, PCBC Revenge and Hyper512.

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.

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.

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.