Background on privacy in Web3
One of the main goals of blockchains such as Ethereum is decentralization. One of the characteristics which currently enables decentralization is that all transactions are kept in a public ledger. Everyone has the ability to see everything and every transaction that happens on the Ethereum and Bitcoin blockchains. Aztec Network is a protocol that seeks to deliver privacy to users of the Ethereum network without sacrificing security.
ZK Rollups are new methods to make Ethereum more scalable and private by executing groups (called "blobs") of transactions outside of L1, and then posting their transaction data back onto L1. This reduces gas costs because the “blobs” can be more efficiently validated on L1 than large numbers of individual transactions can. These rollups make use of ZK proofs so that users can make private transactions on their networks. For more information you can read our Rundown of ZK Proofs.
Aztec Network is the pioneer ZK-Rollup on Ethereum. It seeks to allow Dapps (decentralized applications) to achieve scalability through increased efficiency and lower gas costs, while maintaining user privacy. The Rollup mechanism has been secured by their own native zero knowledge proving mechanism.
ZK.money is a Layer 2 private transfer protocol application built on the Aztec Network. Users can send their ETH to the protocol to “shield it” ensure the privacy of their transaction history. Having a token shielded means that it is protected by a zkSNARK (zero-knowledge proof cryptography) shell. Users can anonymously send, receive and swap tokens, without this data being available to the wider public. Currently the transaction limit on zk.money is 5 ETH or 10K DAI at a time.
Currently using zk-money means you are relying on the Aztec network to process all of your transactions on their L2 rollup. They do have plans to onboard more rollup providers which would improve this situation. In case Aztec were to suddenly shut down, there is an emergency mode to allow users to withdraw funds from the system directly from the contract.
Zk.money is an experimental protocol and should be treated as such. It has had rigorous internal audits but yet to have had an external audit.
This has become an even bigger issue lately with one of the most popular privacy apps on Ethereum Tornado Cash being sanctioned by OFAC and one of the devs who worked on the protocol being arrested in Amsterdam. Regardless of whether those actions hold up in court, any protocol that can solve the privacy issue while maintaining compliance and avoiding government sanction will surely gain a large market share.
FTX recently froze a user's account who sent coins to Aztec's zk.money. Perhaps in the expectation they may fall foul of government regulations in the future. So DYOR and invest at your own risk.
Privacy is a big issue with using the blockchain as well gas efficiency. Aztec Network seeks to address both of these problems with zk.money and it will be exciting to see how they do going forward.