Aztec Network Launches Public Testnet, Advancing Onchain Privacy

Aztec Network, a zk rollup built on Ethereum, has launched its public testnet, marking a significant advancement in the quest for onchain privacy while maintaining smart-contract programmability and decentralization. This development leverages zero-knowledge technology to encrypt user balances and transactions on the Layer 2 (L2), ensuring privacy around details such as the sender, recipient, or the transaction itself. The programmability of Aztec is enabled by Noir, a Rust-like language for zero-knowledge circuits developed by the company. Noir allows developers to write smart contracts that can perform shielded loans or private voting without needing to learn cryptography, making it easier to build decentralized applications (dapps) with privacy features that seamlessly blend with Ethereum’s existing infrastructure.

Unlike most Layer 2 solutions, Aztec makes significant modifications to the chain’s execution layer. Public transactions on Aztec are executed through its custom Aztec Virtual Machine (AVM), while private transactions are offloaded to a client-side environment known as the Private eXecution Environment (PXE). PXE is used to generate proofs and run smart contract logic privately. Transaction proofs are then aggregated into single proofs for Ethereum settlement. Client-side generation of zk proofs is typically expensive, but Aztec’s new Layer 2 keeps costs down. This is largely thanks to its PLONK proving system, which makes it simpler to generate client-side proofs on expensive hardware. PLONK was co-invented by Aztec co-founder and CEO Zachary Williamson. The company’s client-side Prover incorporates the latest in PLONK research with the Protogalaxy folding scheme and a unique technique called Goblin Plonk to accelerate recursion. Additionally, Aztec built its own programming language, Noir, from scratch to compile programs directly into zero-knowledge circuits, bypassing the overheads seen with zero-knowledge virtual machines.

Contrary to popular belief, most zk rollups do not actually leverage zero-knowledge technology for privacy encryption. Instead, they use the technology primarily for the size compression of transactions to scale throughput without encrypting user data. Aztec, however, applies zk proofs not just for verification but also to enable end-to-end encryption of transaction metadata. Privacy is optional, aligning with Aztec’s goals of developing a chain that offers flexible privacy and selective disclosure. This architecture is not possible on the Ethereum Layer 1 today, where all details would be publicly exposed. It is also not possible on other Layer 1 chains like Monero or Zcash, which allow for private payments but lack smart contract programmability. Aztec’s approach challenges the current view of blockchain privacy as an all-or-nothing proposition, offering a more nuanced solution.

Aztec’s testnet already has over 100 sequencers in its Devnet and Provernet networks, paving the way for decentralization starting from day one. This development is a significant milestone in the quest for onchain privacy, smart-contract programmability, and decentralization, positioning Aztec as a leader in the field of privacy-focused blockchain solutions. The launch of the public testnet opens access to all developers, allowing them to customize their contracts with both public and private components while deploying them to a fully decentralized network. This marks a new era for Web3, where privacy and decentralization are seamlessly integrated into the blockchain infrastructure.