Privacy continues pushing full steam ahead. With new funding, high-stakes court cases, and technical milestones, our industry is recommitting to onchain privacy as a first principle. One of the longest-running efforts is Aztec, which just launched its "Adversarial Testnet" — a permissionless trial ahead of its upcoming mainnet. Here’s why Aztec is still leading Ethereum’s privacy frontier.👇 ~~ Analysis by @davewardonline ~~ What is Aztec? @aztecnetwork is a privacy-first Ethereum Layer 2 that supports both public and private smart contract functions, letting privacy be a choice. It uses a dual execution model: private smart contracts run client-side, inside your browser; public ones run on Aztec’s decentralized node network. Both execution types interoperate through zero-knowledge proofs (ZKPs), connecting private and public computation. Unlike most L2s, Aztec isn’t EVM-compatible. Instead, it uses its own language, Noir, built for zero-knowledge proofs. Why not Solidity? Aztec claims the EVM’s transparent state makes real privacy impossible without security tradeoffs. Noir hides ZK complexity and offers a Rust-like syntax that doesn’t require deep cryptographic expertise. The Private Execution Environment (PXE) The PXE (pronounced "pixie") is Aztec’s client-side privacy engine — a local library that runs in your browser. It’s part wallet, part scanner, part proof generator. It stores secrets, detects private assets, and builds the proofs that enable private transactions. ➢ Manages secrets — Stores private keys, decrypted notes, and metadata locally. Handles multiple accounts and address books. ➢ Builds transactions — Simulates, prepares, and proves private transactions (e.g., swaps), packages them with encrypted outputs, and sends to an Aztec node. ➢ Tracks private assets — Uses a UTXO model. Encrypted notes are published to Ethereum as logs. PXE scans and decrypts them locally, then displays balances like a wallet. PXE handles the private side. For public execution, there’s the Aztec Virtual Machine. The Aztec Virtual Machine (AVM) The AVM runs public smart contract logic on the Aztec network. It communicates with PXE, enabling private functions to trigger public actions — and vice versa. Need public price data for a private swap? Want a public NFT auction that settles to a private address? This kind of hybrid logic is possible through PXE-AVM interaction. Aztec rollups compress both private (PXE) and public (AVM) transactions into batches, post them with proofs to Ethereum, and maintain encrypted notes as verifiable but unreadable blobs. Result: private and public logic settle together on Ethereum without compromising privacy or composability. What You Can Do Now Several tools are live for those looking to test ahead of mainnet: ➢ Aztec Sandbox — Local dev environment for building and simulating private dapps. ➢ Aztec Playground — Browser tool to run testnet contracts and transactions. No setup required. ➢ Join the Validator Set — Register with ZKPassport, run nodes, earn roles and rewards. Overall, Aztec offers a strong vision of encrypted computation alongside public state. With 16K nodes already running, the move from research to deployment looks close. Keep up now so you're ready later.