A16z Crypto criticizes the misuse of the ZK term, upgrades Jolt zkVM towards true ZK

A16z Crypto – the Web3 investment arm of the leading venture capital firm Andreessen Horowitz – has publicly criticized the widespread but inaccurate use of the term “ZK” within the developer community in a recent blog post introducing Jolt zkVM.

According to the article, “most zkVMs are not truly zero-knowledge in the strict sense—unless a costly ‘wrapping’ process is applied.” This process often requires recursive proof verification, where zkVM proofs are verified inside another proof system that is genuinely zero-knowledge. This approach not only consumes significant computational resources but also often sacrifices transparency due to the need for a trusted setup.

The authors also note that in many cases, “zk” has become shorthand for “succinctness”—meaning proofs that are small in size and quick to verify—instead of guaranteeing true zero-knowledge privacy.

A16z Crypto emphasizes that as the community increasingly focuses on privacy—which requires true zero-knowledge to protect sensitive data—the misuse of the term is becoming a serious issue.

What is ZK proof?

Zero-knowledge proof (ZK proof) is a cryptographic technique that allows one party (the prover) to convince another party (the verifier) that a statement is true without revealing any underlying information beyond the fact that the statement is correct.

Originally developed in academic settings, the first large-scale commercial application of ZK proof is believed to have appeared in the crypto industry with the launch of Zcash. This project implemented zk-SNARKs—a form of succinct proof—to provide on-chain privacy by hiding transaction data.

Since then, zero-knowledge cryptography has been widely adopted in many new blockchain models, especially as scaling solutions for Ethereum Layer 2 and zk-Rollups.

Privacy is also becoming a key concern for crypto developers and investors, as many believe that the absolute transparency of most current blockchains could hinder widespread adoption, particularly among financial institutions.

For example, Barry Silbert, CEO of Digital Currency Group, recently expressed expectations that significant capital will flow into privacy-focused blockchains.

Jolt’s solution

On its end, A16z’s open-source Jolt zkVM announced a major upgrade on Tuesday, enabling true native zero-knowledge proof support.

A Zero-Knowledge Virtual Machine (zkVM) is an environment capable of executing programs and generating proofs that confirm code execution without revealing input data.

Previously, like many other applications, Jolt mainly used ZK proofs to achieve succinctness rather than full privacy. To address this limitation, the development team adopted a “folding scheme” mechanism originating from the 1990s.

Specifically, Jolt integrated the NovaBlindFold mechanism to produce blinded proofs, which prevent information leakage and make the system suitable for privacy-preserving applications.

According to the blog post, the final result is a zero-knowledge proof only about 3 KB larger than Jolt’s previous proof without ZK attributes, indicating that the additional size overhead is relatively small compared to the privacy benefits gained.