Zero-Knowledge Security
Zero-knowledge security refers to correct and secure implementation of zero-knowledge proofs, a cryptographic method that enable one party to prove the truth of a statement to another without revealing any underlying information.
This approach is essential for various solutions, such as Ethereum Layer 2 ZK-rollups (scaling), privacy-focused applications, and Zero-Knowledge Virtual Machines (ZK-VMs). A critical aspect of zero-knowledge security is ensuring that zero-knowledge circuits (software code) are properly constrained to prevent vulnerabilities, such as underconstrained circuits, which can lead to security breaches.
What are zero-knowledge circuits?
Zero-knowledge circuits are cryptographic constructs used in zero-knowledge proofs to represent mathematical computations or logical conditions in a structured, verifiable format.
These circuits serve as the foundation for proving that a statement is true without revealing any private information underlying the proof.
ZK circuits can be written in number of programming languages, such as Circom or R1CS.
In zero-knowledge proof context the “circuit” word always refers to software code, not actual hardware circuits.
What are some examples of zero-knowledge applications?
A well-known use case for zero-knowledge technology is in privacy-focused solutions, where they hide sensitive transaction details while verifying the transaction’s validity. Privacy-preserving blockchains are one example of such solutions.
ZK also play a vital role in other solutions, such as Zero-Knowledge Virtual Machines (ZK-VMs), which enable general-purpose computation using ZK proofs and RISC-V architecture. This allows developers to build ZK applications and verifiable computing solutions without needing specialized knowledge in cryptography.
As zero-knowledge technology evolves, ZK circuits are becoming foundational in a range of blockchain applications, from ZK rollups (Ethereum L2 scaling solutions) to privacy-preserving applications to ZK-VMs.
Zero-knowledge security and audits: introduction
A zero-knowledge security audit is a detailed security review aimed at ensuring zero-knowledge circuits are secure, logically consistent, and free from vulnerabilities.
Traditional smart contract audits typically focus on code correctness, vulnerability checks, and adherence to best practices, whereas zero-knowledge audits also need to ensure the cryptographic elements function correctly without compromising privacy or security.
As an example, in a ZK audit, auditors often need to validate the construction and evaluation of zero-knowledge circuits. Often this is checking underconstrained circuits, or circuits that do not have enough constraints to uniquely determine all the variables in the computation. Multiple solutions may allow the prover to create a seemingly valid proof for an incorrect statement, which may lead to serious vulnerabilities.
A ZK audit also often requires the verification of the cryptographic primitives used, such as hash functions, commitment schemes, and elliptic curve operations, to ensure they are implemented securely and according to the specific requirements of the ZKP protocol.
At Veridise, a ZK audit includes a meticulous line-by-line manual code review by a security analyst, as well as a tool-assisted analysis.
Zero-knowledge security audit: why is it important?
Zero-knowledge audits are crucial as blockchain applications increasingly rely on ZK technology for privacy, scalability, and efficient computation. The risks associated with vulnerabilities in ZK applications are severe, and a single exploit could compromise the integrity of the protocol, potentially leading to significant reputational and/or financial damage.
At Veridise, based on a sample of our 100 recent security audits, we’ve observed that zero-knowledge audits are twice as likely to contain critical or high-severity vulnerabilities compared to non-ZK audits (primarily smart contract audits).
Projects that undergo rigorous zero-knowledge audits are far less susceptible to attacks. A security audit is a critical step for projects seeking to use ZK technology and build trust among their users, partners, and investors.
What is the unique skill set of zero-knowledge security auditors?
Zero-knowledge security auditors require specialized expertise in cryptography, mathematics, and blockchain security. Unlike developers, who write circuits with a primary focus on functionality, auditors bring an adversarial mindset, meticulously identifying vulnerabilities that could affect both the cryptographic and operational aspects of ZK applications.
Auditors must assess specific issues unique to ZKP systems, such as underconstrained circuits, where a lack of constraints could enable a malicious party to generate a false proof. Veridise’s auditors are skilled and experienced at uncovering these issues. We utilize our in-house developed detection tools (Picus) specifically designed for ensuring the correctness of zero-knowledge circuits.
Auditing ZK circuits requires in-depth understanding of cryptographic protocols, cryptographic primitives (e.g., hash functions, commitment schemes), and experience with circuit languages such as Circom.
What makes Veridise the ideal choice for your zero-knowledge security audit?
Competent and experienced zero-knowledge security auditors are few and far between. You can easily “audit” our zero-knowledge security competence at Veridise.
Our team includes several PhDs in program analysis, mathematics, and cryptography, with academic research backgrounds specifically in blockchain and zero-knowledge security. On our team page, you’ll find full bios of our members, detailing their academic research, educational backgrounds, and prior audit experience.
We have contributed to academic research in zero-knowledge security. These insights have fueled the development of our in-house ZK tools, such as Picus. We actively participate in industry conferences, and you can find many of our zero-knowledge-related presentations on our YouTube channel.
Finally, we have audited ZK-related projects such as Risc Zero, Succinct, Linea, Manta, MINA, O1JS, and found critical bugs in Circom-lib libraries itself. We encourage you to ask our previous clients about their experience working with us.
To summarize, Veridise combines a strong academic foundation and in-house ZK tools with extensive experience auditing some of the most critical ZK solutions in the market.
Planning a ZK audit?
Reach out to us as early as possible to secure a spot in our audit schedule to ensure it aligns with your launch timeline.