announcement · zk

zkBitcoin: Use Zero-Knowledge Applications (zkapps) on Bitcoin

David Wong January 31, 2024 1 min

zkbitcoin

In collaboration with Σ0, we released a new primitive called zkBitcoin, which allows for the creation of zero-knowledge applications (zkapps) on Bitcoin via a minimal layer 2 protocol that uses Bitcoin as data availability layer and a committee of participants to perform threshold signatures.

This is a significant milestone for the Bitcoin ecosystem as it augments the capability of the Bitcoin scripting language allowing for larger and more complex application. In addition, it unlocks privacy-preserving applications for Bitcoin.

We're currently running on testnet, and you can try it out by downloading the zkBitcoin CLI.

You can read the whitepaper here, which describes the two types of zkapps that can be created, stateless and stateful, while providing more details about the protocol overall:

If you like videos, you can watch:

We're excited to see what people will build on top of zkBitcoin. If you're interested in running a node for the network, or interested in using the protocol for your own application or L2, shoot us a message!

Keep reading

Latest

Optimizing Cryptography with AI

Many of us are using AI to generate code. Vibe coding cryptography is especially sensitive - you have to uphold strict mathematical correctness. This can lead to wrong security guarantees and soundness bugs. We will discuss what are some patterns to do it well.

Kobi Gurkan · August 11, 2026

Introducing zkvmBlast: Differential Fuzzing for Ethereum's zkVMs

zkVMs are moving to the center of Ethereum's roadmap, which means a bug in a zkVM is turning into a bug in Ethereum itself. We built zkvmBlast, a zkVM-agnostic differential fuzzer that runs the same program across SP1, RISC0, OpenVM, Pico, Zisk, and Airbender against a reference simulator and flags any disagreement. It hunts for both soundness and completeness bugs, with a deliberate focus on completeness, an under-explored class that can turn a single valid block into a liveness failure. We share the first batch of findings.

Stefanos Chaliasos, Martín Ochoa, Varun Thakore · August 10, 2026

Circom-Auditor: Open-Source Skills for Finding Vulnerabilities in Circom Code

We are releasing zk-skills, a set of open-source security skills for AI coding agents, starting with circom-auditor: a first line of defense against vulnerabilities in Circom circuits, compatible with both Claude Code and Codex. On the zkbugs benchmark it detects up to 66 of 70 known bugs when pointed at the vulnerable circuits, and up to 40 of 56 when let loose on the full original codebases, far ahead of existing Circom security tools.

Stefanos Chaliasos, Hao Pham, False Witness Team · August 05, 2026

Recommended

Archetype x zkSecurity - Proof is in the Pudding: ZK on Bitcoin

In Session 09 of "Proof is in the Pudding," we explore the intersection of zero-knowledge proofs and Bitcoin. We break down Bitcoin's UTXO model and Script limitations, then dive deep into approaches for verifying ZK proofs on Bitcoin, from MPC-based techniques to BitVM's optimistic verification with fraud proofs. We cover timelocks, the statelessness problem and Lamport signatures for state, Taproot, simulated covenants, BitVM 3 with hashlocks and garbled circuits, cut-and-choose security, and witness encryption (BABE).

ZK/SEC · April 02, 2026

Reproducing and Exploiting ZK Circuit Vulnerabilities

Check out our latest blog post where we dive into the world of Zero-Knowledge Proof (ZKP) vulnerabilities, sharing our insights from replicating known ZK circuit weaknesses. We’ve launched a GitHub repo with detailed scripts to help you understand, reproduce, and learn from these vulnerabilities. Discover how this hands-on approach aids in grasping attack vectors, testing fixes, and enriching educational resources. Whether you're a researcher or a developer, this post is packed with info to enhance your knowledge and skills in ZKP security. Plus, find out how you can contribute to expanding this invaluable resource!

Stefanos Chaliasos, Chenyang Yu · August 09, 2024

zkSecurity took part in judging the latest zkHack Montreal

We recently had the thrill of judging the latest zkHack competition in Montreal, where developers, researchers, and enthusiasts dove into the world of zero-knowledge proofs and privacy tech. The projects were incredibly innovative, featuring creative applications like ZK breathalyzers and ZK & GPS solutions. Check out the exciting results and insights from this year's event. You won't want to miss what these brilliant minds are bringing to the table!

ZK/SEC · September 02, 2024

More to explore

Watch what we have to say about ZK security in the Node Guardians season 2 episode 1

Catch our cofounder David Wong on the latest episode of Node Guardians, where he chats about ZK security with Sam. Dive into the intriguing world of blockchain auditing, uncover the role math plays, and explore how auditors tackle challenges and rate vulnerabilities. Plus, get insights into the usefulness of formal verification. It's a must-watch for anyone curious about the future of ZK and the nitty-gritty of blockchain security!

ZK/SEC · August 31, 2023

AI meets Cryptography 2: What AI Found in OpenVM's zkVM

We turned zkao (our AI auditor) on OpenVM, a state-of-the-art zkVM, and it found a critical soundness bug: the pairing check accepted a prover-supplied witness without proper subfield checking, which lets a malicious prover forge any pairing equality. It is fixed in OpenVM 1.6.0 and tracked as CVE-2026-46669. This is the second post in our series on bugs our agents found across open source cryptography.

Stefanos Chaliasos, Hao Pham · July 17, 2026

Sum-Check as an Algebraic Tensor Reduction: Part III

This post is all about the maps that let us move between modules without breaking their structure. We’ll see when a map is truly “linear,” when two modules are (secretly) the same, and why two-input maps deserve special attention. Along the way, (bi-)linear maps and isomorphisms become less like abstract definitions and more like tools we can actually use. By the end, we’ll have all the tooling we need to tackle abstract tensor products head-on.

Marco Besier · May 18, 2026