Founded in 2017 and co-led by A16Z and Paradigm, the ancient privacy chain Aztec is about to launch its TGE. Unlike Zama, which integrates a privacy layer onto other chains through FHE, Aztec's privacy capabilities are more native and adopt a hybrid privacy model. This allows users to specify which data is public and which remains private. For private data, Aztec uses a model similar to Bitcoin's UTXO, as UTXO is inherently better suited for privacy compared to the account model. In an account model, for example, if you hold 100U and transfer 30U, leaving 70U, anyone can easily deduce who you sent the funds to by observing wallet asset changes on-chain. Thus, any operation that directly modifies wallet-related data is fundamentally opposed to privacy. In Aztec, every asset is called a "note," which contains information like funds and ownership. When transferring assets, the process doesn't directly modify the note. Instead, the old note is destroyed, and one or more new notes are created. Each note has a "nullifier," which is an encrypted fingerprint used to identify whether the note has been used or destroyed. As a project nearly a decade old, Aztec's privacy technology has already been adopted by zkSync, Polygon, and others. Even JPMorgan included it in its financial privacy evaluation back in 2019.