# Aztec

> Aztec: Privacy L2. Technology: zero-knowledge proofs.

Part of the Soda Labs Privacy Hub, a neutral directory of the on-chain privacy
landscape: https://www.sodalabs.xyz/privacy-hub

## Key facts

- Entry type: Privacy project
- Category: Privacy L2
- Technology: Zero-knowledge proofs (ZK)
- Website: https://aztec.network
- Tags: ZK, L2, smart contracts
- Canonical page: https://www.sodalabs.xyz/privacy-hub/aztec

## Overview

Aztec has been building private smart contracts for Ethereum since 2017, and along the way it wrote much of the toolchain the wider field now uses. Noir, its circuit language, has become one of the most widely adopted ways to write zero-knowledge programs anywhere. Alpha V5 activated on mainnet in July 2026, bringing private transactions live at fees under five cents, with execution and proving happening on the user's own device so plaintext never leaves it. The road here has been a long one. Aztec Connect, the first product, was retired in 2023, and contracts left deprecated behind it were exploited for 2.1 million dollars three years later. Private state is modeled as per-user notes, an elegant fit for individual confidentiality and a different shape from the shared private state institutions work across.

## About Zero-knowledge proofs

One party proves a statement about hidden data is true without revealing the data the statement is about. Compared side by side with the other approaches at https://www.sodalabs.xyz/taxonomy.

## Sources

- [Docs](https://docs.aztec.network)
- [Noir, the circuit language](https://noir-lang.org)
- [Protocol source](https://github.com/AztecProtocol/aztec-packages)
- [Aztec Connect, retired 2023](https://www.coindesk.com/business/2023/03/13/defi-privacy-bridge-aztec-connect-sunsets-after-less-than-a-year)
- [Deprecated contract incident, 2026](https://thedefiant.io/news/hacks/aztec-connect-deprecated-contract-exploit-2-1m-zk-proof)

## Related entries

- [Aleo](https://www.sodalabs.xyz/privacy-hub/aleo): Privacy L1
- [Hinkal](https://www.sodalabs.xyz/privacy-hub/hinkal): Private DeFi layer
- [Miden](https://www.sodalabs.xyz/privacy-hub/miden): Client-side proving chain (upcoming)
- [Mina](https://www.sodalabs.xyz/privacy-hub/mina): Succinct blockchain
- [Namada](https://www.sodalabs.xyz/privacy-hub/namada): Multi-asset shielded L1
- [Noir](https://www.sodalabs.xyz/privacy-hub/noir): ZK programming language