educative · zk · halo2

Become a Halo2 Hero: Master Zero-Knowledge Proofs with Our New Course

Mathias Hall-Andersen November 14, 2024 1 min

Halo2 course

In collaboration with the Zircuit development team, we are excited to announce the release of a course on Halo2 development. Unlike the excellent Halo2 book which focuses on the proof system itself, this course focuses on teaching Rust developers how to develop Halo2 circuits from scratch -- without any prior knowledge of Halo2, PlonK or developing circuits for zkSNARKs required. You don't need to be a cryptographer to follow along! We start from the very basics and build up to more complex circuits with lookups, challenges and more. At the end of the course, you should become a true Halo Hero!

All code in the course comes with complete runnable examples available in the accompanying GitHub repository. This means that any code snippet in the course can be run as a self-contained example!

Get started with Halo2 development today at halo2.zksecurity.xyz.

Keep reading

Latest

Fiat-Shamir Bugs: How One Missing Line Breaks a Proof System

This blog post looks at Fiat-Shamir from a practical security perspective: it explains why something that seems simple in theory can become surprisingly easy to get wrong. By using vulnerabilities found in real-world projects, we give developers and reviewers a better way to think about Fiat-Shamir when designing, implementing, and auditing proof systems.

Giap Vu, David Wong · September 19, 2026

Better Codes - and how they can be worse if you're not careful

An exploration of how an AI tried to work around a security feature to handle a theorem that was hard to prove.

Kobi Gurkan · September 14, 2026

The Year Finding and Exploiting Bugs Became Cheap, and What to Do About It

The economics of security have changed. AI has made finding and exploiting bugs cheaper, including in cryptographic and zero-knowledge code, while validation and remediation remain slow. Here is our view of what happened, what comes next, and how teams should change the way they secure their stack to defend against AI-assisted attackers.

Stefanos Chaliasos · September 07, 2026

Recommended

Halo2's Elegant Transcript As Proof

In this blog post, we explore a clever design in Zcash's halo2 implementation for securing the Fiat-Shamir transformation. By using a mutable transcript, the process ensures that values are automatically absorbed, reducing potential bugs. You'll find explanations of the distinct roles of `write` and `read` functions for points and scalars, highlighting how this abstraction makes the prover-verifier interaction seamless and secure. If you're curious about the inner workings of cryptographic protocols, this is a fascinating read.

David Wong · September 30, 2025

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

𝒫𝔩𝔬𝔫𝒦: A Hands-On Deep Dive

𝒫𝔩𝔬𝔫𝒦’s many layers (selector polynomials, wiring permutations, quotient tests, random challenges and KZG commitments) can be overwhelming. Our zkSecurity tutorial uses a single running example to demystify them all. Build tables and interpolate low-degree BN254 polynomials, encode gate and wiring constraints, run deterministic and probabilistic zero-tests, then layer in randomness and KZG commitments to produce a full Fiat–Shamir proof. Grab the Jupyter Notebook (Sage or Cocalc), or work in your favorite language with our guided test cases.

Martín Ochoa · August 05, 2025

More to explore

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

zkNews Is Now Open to Everyone

zkNews is now open to everyone. When we first launched, access was limited to a small beta group to keep things stable while we found our footing. That rate limit is gone. Anyone can now sign up, submit links, and join the discussion at news.zksecurity.xyz. Come help us build the home for zero-knowledge news.

ZK/SEC · June 06, 2026

Public report of Aleo's synthesizer

We were tasked with auditing Aleo's synthesizer for their blockchain, diving deep into its code and uncovering some important findings along the way. The synthesizer is crucial for deploying and executing user programs, utilizing zero-knowledge proofs to maintain privacy and efficiency. Readers will get a glimpse into how Aleo uses their Leo programming language, the intricate process of synthesizing proof circuits, and how function execution and program deployment flows occur on their platform. This post offers insights into Aleo’s unique approach to tackling challenges similar to those faced by Ethereum but with an innovative twist that includes privacy features and reduced costs.

ZK/SEC · January 02, 2024