Aztec

Aztec is a privacy-first Layer 2 (L2) blockchain built on Ethereum that focuses on enabling confidential transactions and private smart contract execution. Unlike Ethereum's base layer, where all transactions and contract states are publicly visible, Aztec introduces privacy by using zero-knowledge proofs and a novel architecture that separates private and public states. It stores private state as encrypted Unspent Transaction Outputs (UTXOs) accessible only to their owners, while public state is maintained in a Merkle tree. This design allows developers to build decentralized applications (dapps) that preserve user privacy without sacrificing composability with Ethereum's public ecosystem.

Aztec is not EVM-compatible; instead, it extends Ethereum by introducing a new virtual machine (the Aztec Virtual Machine) that supports both private and public functions. Private functions execute and prove computations on the user's device, while public functions run on the Aztec VM. This hybrid approach enables seamless interaction between private and public states and messaging with Ethereum. Developers can start building on Aztec using the Aztec Sandbox environment and the open-source SDKs, with comprehensive documentation and tutorials available to guide integration.

What sets Aztec apart is its strong emphasis on privacy at the protocol level combined with Ethereum compatibility, enabling DeFi developers and enterprises to build confidential applications that interoperate with Ethereum's ecosystem. Aztec's architecture supports composability between private and public execution, which is uncommon among privacy solutions. The project is actively maintained by Aztec Labs, with a rich GitHub repository and an engaged developer community. Use cases include private DeFi transactions, confidential asset transfers, and privacy-preserving enterprise blockchain applications. Developers can get started by exploring the Aztec documentation, running nodes, or using the Aztec Starter repository on GitHub.