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

Variants of KZG: Part V, Multilinear Commitments with Mercury

In this final post of the series, we extend univariate KZG commitments to multilinear polynomials through Mercury. Building on Gemini, we fold half of the variables at once, use polynomial division to bind this large fold to the original commitment and reduce the remaining multilinear evaluations to a batched inner product check. We then walk through the end-to-end opening protocol. We conclude by examining its proof size, prover cost and verifier cost.

Varun Thakore · August 17, 2026

Variants of KZG: Part IV, Multilinear Commitments with Gemini

In this blog post, we extend univariate KZG commitments to multilinear polynomials through Gemini. We introduce recursive partial evaluations, derive the split-and-fold identity and express each fold as a univariate identity that can be checked using KZG openings. We then walk through the end-to-end opening protocol. We conclude by examining its proof size, prover cost, and verifier cost.

Varun Thakore · August 12, 2026

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

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

A Gentle Introduction to the MPC-in-the-Head Transformation

In this blog post, we dive into the fascinating world of zero-knowledge proofs using the MPC-in-the-Head transformation, a clever method that constructs proof systems from any secure multiparty computation protocol. Originally proposed in 2007, this transformation uses a creative approach involving "imaginary parties" to prove knowledge without revealing it. We explain how this technique can be applied to develop post-quantum signature schemes, providing insights into its practical implications and efficiency. By exploring these concepts, readers will uncover a unique intersection of cryptography and computer science.

Giorgio Dell'Immagine · February 20, 2025

Private delegated computation is here, and there will be bugs!

Dive into the intriguing world of zero-knowledge cryptography with us as we unravel its connection to trusted and confidential computing. Learn why this tech is making us rethink security like never before. From the evolution of private and delegated computing to the revolutionary power of zero-knowledge proofs, we'll explore how these advancements are shaping industries beyond cryptocurrencies. With big players like Microsoft jumping on board and the potential for new applications, zero-knowledge cryptography is poised to redefine digital trust. Join us on this journey as we launch our new security consultancy, designed to navigate and secure this cutting-edge landscape.

ZK/SEC · May 30, 2023

Kocher's Timing Attack: A Journey from Theory to Practice

Paul Kocher's 1996 timing attack showed how microsecond differences in execution time could leak private keys from RSA implementations. This tutorial recreates the attack journey from clean operation counting through noisy wall-clock measurements to sophisticated engineering solutions. Learn the variance distinguisher, explore schoolbook modular arithmetic, and discover the measurement techniques that make practical timing attacks possible despite system noise.

Martín Ochoa · September 19, 2025