Aztec has launched the alpha version of its v5 execution layer, introducing a programmable privacy framework that allows Ethereum applications to process both public and private state within the same layer-2 environment.
Summary
- Aztec has released the alpha version of its v5 execution layer, bringing programmable privacy to Ethereum through zero knowledge powered smart contracts.
- The new architecture processes private computations on user devices while verifying transactions on chain without exposing sensitive data.
- Aztec said the execution layer supports confidential decentralized applications with features designed to reduce front running and MEV risks.
Aztec Labs announced the alpha release of its v5 execution layer, describing it as a step toward making privacy-native smart contracts practical on Ethereum.
The new architecture allows developers to build decentralized applications that combine confidential user data with public blockchain state while relying on zero-knowledge proofs to verify transactions without exposing sensitive information.
Unlike Ethereum’s base layer, where every validator processes and stores transaction inputs, outputs, and execution data to reach consensus, Aztec’s execution layer moves private computation to the user’s device. Instead of revealing transaction details to the network, the system generates cryptographic proofs locally before submitting them for verification on-chain, reducing the amount of visible transaction data while preserving Ethereum’s security guarantees.
Client-side execution changes how private transactions are processed
At the center of the release is a client-side zero-knowledge execution engine integrated with Noir, Aztec’s domain-specific programming language for private smart contracts. Rather than executing confidential transactions across every network node like the Ethereum Virtual Machine, the system performs private computations on user hardware before generating recursive Succinct Non-Interactive Arguments of Knowledge, or SNARKs.
Those proofs allow the network to verify that state changes are valid without exposing plaintext inputs, transaction values, or account identities. According to Aztec Labs, the model cuts unnecessary data disclosure while maintaining mathematical guarantees that transactions have been executed correctly.
The architecture also introduces a hybrid state model designed to overcome one of the biggest engineering challenges facing privacy-focused blockchains. Purely private execution environments often struggle when multiple users attempt to update the same public state at the same time, creating state contention that limits interaction with shared decentralized finance infrastructure.
To address that limitation, Aztec separates private and public state management. Private assets are stored in UTXO-like note trees, while public data is maintained through key-value trees. During execution, private functions can generate deferred public function calls that are processed later within the same transaction lifecycle, allowing confidential and public operations to work together without sacrificing deterministic execution or creating race conditions.
The execution model is intended to support applications that require confidential computation while still interacting with Ethereum’s public ecosystem, including shared liquidity pools and other decentralized finance protocols.
Privacy model targets decentralized finance and enterprise applications
Beyond transaction privacy, the execution layer introduces features that could reduce several long-standing issues in blockchain execution.
According to Aztec Labs, transaction details remain hidden before state commitment, making it significantly harder for external observers to reorder pending transactions or exploit visible transaction data through Maximal Extractable Value strategies.
The architecture also provides building blocks for applications such as confidential order matching, private liquidity provisioning, and selective compliance systems that disclose only required information through viewing keys instead of exposing complete user records.
Those capabilities build on Aztec’s long-standing focus on programmable privacy rather than simple anonymous token transfers.
Speaking to crypto.news in April 2025, Aztec Labs co-founder and CEO Zac Williamson said blockchain privacy should go beyond hiding wallet addresses.
He described user privacy, confidential transaction data, and private smart contract execution as the three pillars needed for practical on-chain privacy, calling them “the holy grail of blockchain privacy.”
Williamson also argued that privacy should not be treated as a separate segment of the industry, saying, “all crypto will be private” as programmable privacy becomes part of mainstream blockchain applications.
Discussing compliance, Williamson said privacy preserving systems should rely on selective disclosure instead of complete anonymity. He pointed to ZKPassport as an example, explaining that users can tap an NFC enabled passport to generate a zero knowledge proof and choose “what information you want to disclose,” whether it is nationality, age, or other identity attributes.
He said the technology is “permissionless, it’s privacy preserving, and it ensures strong compliance,” adding that such systems are “a lot more powerful” than existing privacy solutions because they combine privacy with programmable compliance.
That vision expanded further in May 2026 when Aztec Labs acquired ZKPassport while committing to keep the passport verification platform open source. The acquisition brought the privacy-focused identity infrastructure directly into Aztec’s ecosystem, allowing developers to combine programmable privacy with zero-knowledge identity verification across Ethereum-compatible networks.
The technology had already been tested on Aztec’s network to help reduce Sybil attacks by allowing participants to prove they were unique individuals without revealing their identities. It was also used during the AZTEC token sale to perform sanctions screening while keeping participant information private.
Alpha release follows security incidents involving legacy products
The execution layer arrives shortly after Aztec Labs dealt with security issues involving products that had already been retired.
Earlier this month, Aztec Labs disclosed that it was investigating a potential exploit involving a deprecated payments product launched in 2021 after roughly $2 million was transferred from an immutable smart contract. The company said the affected system had been discontinued in 2022 and operated without administrator keys, preventing the team from pausing or upgrading the contract.
Separately, another deprecated product, Aztec Connect, lost approximately $2.1 million after attackers exploited an old immutable RollupProcessorV3 contract. Aztec Labs said the incidents were unrelated to the active Aztec network.
The Aztec Foundation also stated that neither exploit had any connection to the current network or the AZTEC ERC-20 token, emphasizing that the affected contracts belonged to legacy infrastructure that had remained live on Ethereum after the products were sunset.
