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Zircuit is a universal Rollup that aims to use zk proofs in the future. It is based on the Optimism Bedrock architecture, employing AI to identify and stop malicious transactions at the sequencer level.


Value Locked
$474.49 M34.2%
Canonically Bridged
$269.48 M
Externally Bridged
$200.87 M
Natively Minted
$4.13 M

  • Tokens
  • Daily UOPS
    0.2333.3%
  • 30D tx count
    583.35 K

  • Stage
    Stage 0
  • Type
    Optimistic Rollup
  • Purpose
    Universal
  • Sequencer failureState validationData availabilityExit windowProposer failure

    Badges

    About

    Zircuit is a universal Rollup that aims to use zk proofs in the future. It is based on the Optimism Bedrock architecture, employing AI to identify and stop malicious transactions at the sequencer level.


    Value Locked
    Activity
    Onchain costs
    Milestones & Incidents

    Zircuit Mainnet Launch

    2024 Aug 5th

    Zircuit is live on mainnet.

    Learn more
    Risk summary
    Proof system is currently under development. Users need to trust the block proposer to submit correct L1 state roots.
    Risk analysis
    Proof system is currently under development. Users need to trust the block proposer to submit correct L1 state roots.
    Sequencer failureState validationData availabilityExit windowProposer failure

    Sequencer failure

    Self sequence

    In the event of a sequencer failure, users can force transactions to be included in the project’s chain by sending them to L1. There is a 12h delay on this operation.

    State validation

    None

    Currently the system permits invalid state roots. More details in project overview.

    Data availability

    Onchain

    All of the data needed for proof construction is published on Ethereum L1.

    Exit window

    None

    There is no window for users to exit in case of an unwanted regular upgrade since contracts are instantly upgradable.

    Proposer failure

    Cannot withdraw

    Only the whitelisted proposers can publish state roots on L1, so in the event of failure the withdrawals are frozen.

    Rollup stage
    ZircuitZircuit is a
    Stage 0
    Optimistic Rollup.
    The requirement for available node software is under review

    Learn more about Rollup stages
    Please keep in mind that these stages do not reflect rollup security, this is an opinionated assessment of rollup maturity based on subjective criteria, created with a goal of incentivizing projects to push toward better decentralization. Each team may have taken different paths to achieve this goal.
    Technology

    Validity proofs (when available) ensure state correctness, but not DA

    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. These proofs are then verified on Ethereum by a smart contract. Currently proofs are optional and state (by default) is considered optimistically to be valid. Moreover, the system doesn’t check that the transactions applied to the state are the ones published by the sequencer.

    • Funds can be stolen if the published state is invalid and the Challenger does not react during the 5h finalization window.

    1. Verifier.sol - Etherscan source code

    All data required for proofs is published on chain

    All the data that is used to construct the system state is published on chain in the form of cheap blobs or calldata. This ensures that it will be available for enough time.

    1. Derivation: Batch submission - OP Mainnet specs
    2. BatchInbox - Etherscan address
    3. OptimismPortal.sol - Etherscan source code, depositTransaction function
    Operator

    The system has a centralized operator

    The operator is the only entity that can propose blocks. A live and trustworthy operator is vital to the health of the system.

    • MEV can be extracted if the operator exploits their centralized position and frontruns user transactions.

    1. L2OutputOracle.sol - Etherscan source code, CHALLENGER address
    2. L2OutputOracle.sol - Etherscan source code, PROPOSER address

    Users can force any transaction

    Because the state of the system is based on transactions submitted on the underlying host chain and anyone can submit their transactions there it allows the users to circumvent censorship by interacting with the smart contract on the host chain directly.

    1. Sequencing Window - OP Mainnet Specs
    2. OptimismPortal.sol - Etherscan source code, depositTransaction function
    Withdrawals

    Regular exit

    The user initiates the withdrawal by submitting a regular transaction on this chain. When the block containing that transaction is finalized the funds become available for withdrawal on L1. The process of block finalization takes a challenge period of 5h to complete. Finally the user submits an L1 transaction to claim the funds. This transaction requires a merkle proof.

    • Funds can be frozen if the centralized validator goes down. Users cannot produce blocks themselves and exiting the system requires new block production (CRITICAL).

    1. OptimismPortal.sol - Etherscan source code, proveWithdrawalTransaction function
    2. OptimismPortal.sol - Etherscan source code, finalizeWithdrawalTransaction function
    3. L2OutputOracle.sol - Etherscan source code, PROPOSER check

    Forced exit

    If the user experiences censorship from the operator with regular exit they can submit their withdrawal requests directly on L1. The system is then obliged to service this request or halt all withdrawals, including forced withdrawals from L1 and regular withdrawals initiated on L2. Once the force operation is submitted and if the request is serviced, the operation follows the flow of a regular exit.

    1. Forced withdrawal from an OP Stack blockchain
    Other considerations

    EVM compatible smart contracts are supported

    OP stack chains are pursuing the EVM Equivalence model. No changes to smart contracts are required regardless of the language they are written in, i.e. anything deployed on L1 can be deployed on L2.

    1. Introducing EVM Equivalence
    Permissions

    The system uses the following set of permissioned addresses:

    ProxyAdmin 0x5B1E…5257

    Admin of OptimismPortal, SystemConfig, L2OutputOracle, L1ERC721Bridge, OptimismMintableERC20Factory, L1StandardBridge.

    Sequencer 0xAF1E…F145

    Central actor allowed to commit L2 transactions to L1.

    Proposer 0xE8C2…7C65

    Central actor allowed to post new L2 state roots to L1.

    Challenger ZircuitMultiSig

    Central actor allowed to delete L2 state roots proposed by a Proposer.

    Admins of SuperchainConfig ZircuitGuardianMultiSig

    Admin of the SuperChainConfig, can configure other roles.

    Monitors of SuperchainConfig 0xf9Fd…5AE5

    Role set up in SuperChainConfig contract that can lower the withdrawal limit for a user.

    ZircuitMultiSig Challenger

    A Gnosis Safe with 6 / 8 threshold. This address is the owner of the following contracts: ProxyAdmin, SystemConfig. It is also designated as a Challenger and SystemOwner of the L2OutputOracle, meaning it can remove L2 state roots and reconfigure L2OutputOracle, including changing the Verifier contract. It can upgrade the bridge implementation potentially gaining access to all funds, and change the sequencer, state root proposer or any other system component (unlimited upgrade power).

    Those are the participants of the ZircuitMultiSig.

    ZircuitGuardianMultiSig Admins of SuperchainConfig

    A Gnosis Safe with 2 / 5 threshold. This address is the permissioned guardian of the system, meaning it can pause all withdrawals. It is also an Admin of the ZircuitSuperchainConfig meaning that it can set roles and permissions for the SuperchainConfig contract.

    Those are the participants of the ZircuitGuardianMultiSig.

    Smart contracts
    A diagram of the smart contract architecture
    A diagram of the smart contract architecture

    The system consists of the following smart contracts on the host chain (Ethereum):

    The L2OutputOracle contract contains a list of proposed state roots which Proposers assert to be a result of block execution. Currently only the PROPOSER address can submit new state roots.

    Can be upgraded by:

    Upgrade delay: No delay

    The OptimismPortal contract is the main entry point to deposit funds from L1 to L2. It also allows to prove and finalize withdrawals. This contract stores the following tokens: ETH.

    Can be upgraded by:

    Upgrade delay: No delay

    It contains configuration parameters such as the Sequencer address, the L2 gas limit and the unsafe block signer address.

    Can be upgraded by:

    Upgrade delay: No delay

    The L1CrossDomainMessenger (L1xDM) contract sends messages from L1 to L2, and relays messages from L2 onto L1. In the event that a message sent from L1 to L2 is rejected for exceeding the L2 epoch gas limit, it can be resubmitted via this contract’s replay function.

    Can be upgraded by:

    Upgrade delay: No delay

    The L1StandardBridge contract is the main entry point to deposit ERC20 tokens from L1 to L2. This contract can store any token.

    Can be upgraded by:

    Upgrade delay: No delay

    The L1ERC721Bridge contract is used to bridge ERC-721 tokens from L1 to L2.

    Can be upgraded by:

    Upgrade delay: No delay

    This contract verifies zk proof (if provided). There is a temporary backdoor allowing to call this contract without the proof.

    Can be upgraded by:

    Upgrade delay: No delay

    The SuperchainConfig contract is normally used to manage configuration values for multiple OP Chains, however this is a separate instance of the SuperChain contract. It manages the PAUSED_SLOT, a boolean value indicating whether the chain is paused, and GUARDIAN_SLOT, the address of the guardian which can pause and unpause the system. It also defines OPERATOR and MONITOR roles which are used to manage throttling (withdrawal limits) on OptimismPortal.

    Can be upgraded by:

    Upgrade delay: No delay

    Value Locked is calculated based on these smart contracts and tokens:

    Main entry point for users depositing ERC20 token that do not require custom gateway.

    Can be upgraded by:

    Upgrade delay: No delay

    Main entry point for users depositing ETH.

    Can be upgraded by:

    Upgrade delay: No delay

    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).

    Knowledge nuggets