Aztec Connect is an open source layer 2 network that aims to bring scalability and privacy to Ethereum. It strives to enable affordable, private crypto payments via zero-knowledge proofs. Additionally it allows to deposit funds into a variety of DeFi Protocols such as LiDo, Element.Fi, etc.
Funds can be stolen if…
Users can be censored if…
MEV can be extracted if…
Each update to the system state must be accompanied by a ZK Proof that ensures that the new state was derived by correctly applying a series of valid user transactions to the previous state. Once the proof is processed on the Ethereum blockchain the L2 block is instantly finalized.
Despite their production use ZK-SNARKs are still new and experimental cryptography. Cryptography has made a lot of advancements in the recent years but all cryptographic solutions rely on time to prove their security. In addition ZK-SNARKs require a trusted setup to operate.
- Funds can be stolen if the cryptography is broken or implemented incorrectly.
All the data that is used to construct the system state is published on chain in the form of cheap calldata. This ensures that it will always be available when needed.
Only specific addresses appointed by the owner are permitted to propose new blocks during regular rollup operation. Periodically a special window is open during which anyone can propose new blocks.
- MEV can be extracted if the operator exploits their centralized position and frontruns user transactions.
Because the block production is open to anyone if users experience censorship from the operator they can propose their own blocks which would include their transactions. Periodically the rollup opens a special window during which anyone can propose new blocks.
- Users can be censored if the operator refuses to include their transactions and users lack resources to propose blocks themselves.
The system consists of the following smart contracts:
- Main Rollup contract responsible for deposits, withdrawals and accepting transaction batches alongside zkProof. This contract stores the following tokens: ETH, DAI, wstETH.
- AztecFeeDistributor 0x4cf3…4927Contract responsible for distributing fees and reimbursing gas to Rollup Providers.
- DefiBridgeProxy 0xA1BB…1487Bridge Connector to various DeFi Bridges.
- StandardVerifier 0x3937…f293Standard Plonk zkSNARK Verifier. It can be upgraded by the owner with no delay.
- VerificationKey28x32 0x8C3B…8966Verification Keys for the Verifier.
The current deployment carries some associated risks:
- Funds can be stolen if a contract receives a malicious code upgrade. There is no delay on code upgrades (CRITICAL).
- RollupProcessor.sol#L395 - Etherscan source code
- StandardVerifier.sol#L37 - Etherscan source code
- RollupProcessor.sol#L359 - Etherscan source code
- RollupProcessor.sol#L97 - Etherscan source code
- RollupProcessor.sol#L347 - Etherscan source code
- RollupProcessor.sol#LL396 - Etherscan source code
- Fast Privacy, Now - Aztec Medium Blog