Aztec released its v5 upgrade in alpha on Tuesday, enabling users to generate end-to-end private transactions directly on consumer devices while maintaining decentralization on Ethereum. The update, passed by token-holder governance and executed onchain on Tuesday, introduces client-side proving that differs from centralized data center approaches used by most ZK projects, according to Aztec co-founder Zac Williamson in an interview with The Block. The upgrade aims to make fully private transactions the default in the Ethereum ecosystem, addressing privacy limitations in current blockchain infrastructure.
Aztec V5 Delivers 2x Faster Proving and 50% Lower Transaction Costs
The v5 upgrade reduces private transaction proving times by more than 2x and cuts the average cost of a fully private transaction by roughly 50%, according to a press release on Tuesday. Average block production time shortened from 14 seconds to six seconds. The network now operates as "the fastest system in the world for proving a fully private transaction entirely on a user's own device," Williamson stated.
The client-side proving process allows users to generate zero-knowledge proofs on phones and consumer laptops rather than relying on centralized data centers. "We've been ruthlessly saying we need to prove things on phones, on consumer laptops, on some random $500 Lenovo piece of junk, if this technology is going to actually have an impact," Williamson told The Block.
The upgrade lowers the cost of verifying rollup proofs on Ethereum by about 40%, bringing the average fee for a fully private token transfer to under $0.05, according to the release. Williamson noted that private transactions currently take longer to complete than standard Ethereum interactions via MetaMask, though the team has made "massive improvements" with planned future releases.
Aztec Addresses V4 Vulnerabilities with Enhanced Security Measures
The v5 release follows Aztec's deprecation of its previous v4 version after vulnerabilities were discovered in March. "V4 was our very first launch, and it coincided with the dramatic acceleration of AI, which impacted the network as well as many others in the ecosystem," Williamson said. "V4 does have active vulnerabilities that we are aware of, so that's why we're not recommending people use it."
The team allocated resources to "an enormous amount of security work" for v5, with 234 security researchers participating in Aztec's bug bounty program, according to the announcement. Williamson stated the project is "very aggressively exploring formal methods and formal verification," referring to mathematical proofs that rigorously verify system behavior. The team plans to release a security roadmap with additional detail.
Aztec launched its Ignition Chain consensus and sequencing layer in mid-November 2025 after years of R&D. The Ignition Chain serves as the foundation for the v5 execution environment and initially ran empty blocks to test decentralization.
Aztec Integrates Private Yield Earning and Ethereum Bridges
Tuesday's release includes use cases such as privately earning yield on Aave via wallet project Nyx. Shield and TRAIN provide bridges to Ethereum. "We've designed Aztec to enable, effectively, a privacy shield for all of crypto," Williamson said. "Initially with Ethereum, but also using bridges elsewhere."
On Monday, Ethereum founder Vitalik Buterin launched a demo for an anonymous message board on Aztec, noting the scaling solution has reached "Stage 2" decentralization by his classification standards for Layer 2s. Buterin is a financial backer of Aztec.
Williamson and his team, including cryptographer Ariel Gabizon, created the PLONK zero-knowledge proof system in 2019. PLONK has since developed into frameworks like Plonky2 and Plonky3 used by Polygon.
Aztec Secures $119 Million in Total Funding from Paradigm and a16z
Aztec has raised over $119 million in total funding, according to The Block Pro's Funding Dashboard. The project raised $100 million in Series B funding in December 2022, with backing from Paradigm and a16z. Aztec also raised $60 million in ETH from 16,741 participants through an AZTEC token sale on Uniswap in December.
FAQ
What did Aztec release on Tuesday?
Aztec released its v5 upgrade in alpha on Tuesday, passed by token-holder governance and executed onchain. The upgrade enables users to generate end-to-end private transactions directly on consumer devices like phones and laptops while maintaining decentralization on Ethereum.
How does Aztec v5 improve transaction performance?
The v5 upgrade reduces private transaction proving times by more than 2x, cuts the average cost of a fully private transaction by roughly 50%, and shortens average block production time from 14 seconds to six seconds. The average fee for a fully private token transfer is under $0.05.
Why did Aztec deprecate its v4 version?
Aztec deprecated v4 after vulnerabilities were discovered in March. According to co-founder Zac Williamson, v4 has active vulnerabilities and the team does not recommend using it. The v5 release includes enhanced security measures with participation from 234 security researchers in the bug bounty program.
