ZK/SEC Quarterly

security · zk

Uncovering the Query Collision Bug in Halo2: How a Single Extra Query Breaks Soundness

We recently discovered a subtle but important soundness issue in Halo2, which we’ve named the query collision bug. It affects certain edge-case circuits and was present in widely used versions, including the main Zcash implementation and PSE’s fork. We disclosed the issue to the relevant teams, including Zcash, PSE, and Axiom, all of whom have since patched it. While no known production circuits were affected, the bug reveals a surprising vulnerability in the proving system that deserves attention.

Suneal Gong July 09, 2025 10 min Read →

announcement · tools

Bug Hunt: Zero-Knowledge, Full-Paranoia, and the AI That Stares Back

Over the past year, we've been diving into whether AI can effectively identify bugs in zero-knowledge circuits and applications, sparking questions about the future of auditing. This led us to develop SnarkSentinel, an AI-powered auditing tool. We'll share what worked, what didn’t, and how our journey with AI could impact auditing. From early challenges with Circom to innovative methods like retrieval-augmented generation and agent-led probing, we'll give you a peek into our findings, including both successes and setbacks with bug detection. Discover how AI might enhance or change the landscape of auditing and what this means for developers and security pros alike.

ZK/SEC July 03, 2025 16 min

Proof is in the Pudding · Part 4

Trust, But Measure: A Friendly Intro to TEEs with Intel TDX

In the latest session of "Proof is in the Pudding," we teamed up with Archetype to explore the basics of Trusted Execution Environments. Through a collaborative whiteboarding session, we break down key concepts and practical applications, making this tech topic accessible and engaging. Dive in to discover how these environments can enhance digital security in a straightforward way.

ZK/SEC June 28, 2025 1 min

security · zk

Uncovering the Phantom Challenge Soundness Bug in Solana's ZK ElGamal Proof Program

In June 2025, we uncovered a serious soundness issue in Solana's ZK ElGamal Proof Program that could let attackers manipulate confidential token transfers undetected. We worked with the Anza team to quickly address the flaw by pausing and disabling vulnerable components. This post dives into the root cause, which was a subtle mistake in handling prover-generated challenges within sigma OR proofs, revealing broader lessons in zero-knowledge protocol security. If you're interested in cryptographic protocol design, this could provide valuable insights.

Suneal Gong June 26, 2025 9 min

Common Circom Pitfalls · Part 1

Common Circom Pitfalls and How to Dodge Them, Part 1

Programming in Circom comes with its fair share of challenges. After reviewing numerous Circom codebases, we’ve identified certain anti-patterns that occur frequently. In this series, we’ll provide a comprehensive overview of these issues to help you avoid the most common pitfalls. Of course, this won’t be a complete list of every mistake possible (Circom has plenty of ways to trip you up). But the footguns we’ll cover are the ones that tend to catch developers off guard the most.

Marco Besier June 24, 2025

Lattice SNARKs · Part 1

Proofs On A Leash: Post-Quantum Lattice SNARK With Greyhound

In this engaging blog post, we dive into the future of cryptography by exploring how lattice-based proof systems could fend off the quantum threat. We break down Greyhound, a promising lattice-based solution, explaining its transparent nature, efficient construction, and adaptability with today's systems. Along the way, you'll get a glimpse of key concepts like lattices, Ajtai commitments, and how Greyhound cleverly ensures security and efficiency. Whether you’re curious about the cutting-edge of cryptographic research or just want to understand the basics of quantum-resistant solutions, this post offers both depth and clarity.

David Wong June 03, 2025

Also in this issue 1 more article

May 01, 2025 Optimizing Barrett Reduction: Tighter Bounds Eliminate Redundant Subtractions Suneal Gong