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Base is an Optimistic Rollup built with the OP Stack. It offers a low-cost and builder-friendly way for anyone, anywhere, to build onchain.


Value Locked
$7.75 B3.18%
Canonically Bridged
$2.00 B
Externally Bridged
$98.89 M
Natively Minted
$5.64 B

  • Tokens
  • Daily TPS
    69.601.42%
  • 30D tx count
    160.74 M

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

    Badges

    About

    Base is an Optimistic Rollup built with the OP Stack. It offers a low-cost and builder-friendly way for anyone, anywhere, to build onchain.


    Value Locked
    Activity
    Onchain costs
    Milestones & Incidents

    Base starts using blobs

    2024 Mar 14th

    Base starts publishing data to blobs.

    Learn more

    Chain stall

    2023 Sep 5th

    Due to an RPC issue, the sequencer stops producing blocks for ~30 minutes.

    Learn more
    Risk summary
    Risk analysis
    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
    BaseBase is a
    Stage 0
    Optimistic Rollup.

    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

    Fraud proofs are not enabled

    OP Stack projects can use the OP fault proof system, already being deployed on some. This project though is not using fault proofs yet and is relying on the honesty of the permissioned Proposer and Challengers to ensure state correctness. The smart contract system permits invalid state roots.

    • Funds can be stolen if an invalid state root is submitted to the system (CRITICAL).

    1. L2OutputOracle.sol - Etherscan source code, deleteL2Outputs function

    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
    State derivation
    Node software

    The rollup node is composed of two software components: op-node, implementing consensus related logic, and op-geth, implementing execution logic. The configuration file can be found here.

    Compression scheme

    Data batches are compressed using the zlib algorithm with best compression level.

    Genesis state

    The genesis file can be found here.

    Data format

    The format specification of Sequencer’s data batches can be found here.

    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 7d 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:

    Challenger is an actor allowed to delete state roots proposed by a Proposer.

    Guardian is an actor allowed to pause deposits and withdrawals.

    Proposer EOA

    Proposer is an actor allowed to post new state roots of current layer to the host chain.

    Sequencer EOA

    Sequencer is an actor allowed to commit transactions from current layer to the host chain.

    LivenessModule 0x0454…a748
    • Can act on behalf of SecurityCouncilMultisig.
    • Is a Guardian (acting via SuperchainGuardianMultisig, SecurityCouncilMultisig).
    • used to remove members inactive for 98d while making sure that the threshold remains above 75%. If the number of members falls below 8, the FoundationMultisig_1 takes ownership of the multisig

    Used in:

    BaseMultisig2 0x1453…E056
    • This is a Gnosis Safe with 3 / 11 threshold.
    • Can act on behalf of Challenger1of2.
    • Is a Challenger (acting via Challenger1of2).
    • Can change configuration of SystemConfig - it can update the preconfer address, the batch submitter (Sequencer) address and the gas configuration of the system.
    SuperchainProxyAdminOwner 0x5a0A…3d2A
    • This is a Gnosis Safe with 2 / 2 threshold.
    • Can act on behalf of SuperchainProxyAdmin.
    • Can change configuration of Lib_AddressManager (acting via SuperchainProxyAdmin) - set and change address mappings.
    • Can upgrade implementation of SuperchainConfig (acting via SuperchainProxyAdmin).

    Used in:

    SuperchainProxyAdminOwner participants (2) FoundationMultisig_1SecurityCouncilMultisig

    Those are the participants of the SuperchainProxyAdminOwner.

    BaseAdminMultisig 0x7bB4…595c
    • This is a Gnosis Safe with 2 / 2 threshold.
    • Can act on behalf of ProxyAdmin.
    • Can change configuration of AddressManager (acting via ProxyAdmin) - set and change address mappings.
    • Can upgrade implementation of OptimismMintableERC20Factory, OptimismPortal, L2OutputOracle, L1ERC721Bridge, SystemConfig (acting via ProxyAdmin).
    • Can upgrade implementation of L1StandardBridge (acting via ProxyAdmin) - upgrading bridge implementation allows to access all funds and change every system component.
    BaseAdminMultisig participants (2) BaseMultisig1FoundationMultisig_2

    Those are the participants of the BaseAdminMultisig.

    FoundationMultisig_2 0x9BA6…6b3A
    • This is a Gnosis Safe with 5 / 7 threshold.
    • Member of BaseAdminMultisig.
    • Can act on behalf of Challenger1of2, DeputyGuardianModule.
    • Is a Challenger (acting via Challenger1of2).
    • Is a Guardian (acting via SuperchainGuardianMultisig, DeputyGuardianModule).

    Used in:

    Those are the participants of the FoundationMultisig_2.

    SecurityCouncilMultisig 0xc281…Bd03
    • This is a Gnosis Safe with 10 / 13 threshold. It uses the following modules: LivenessModule (used to remove members inactive for 98d while making sure that the threshold remains above 75%. If the number of members falls below 8, the FoundationMultisig_1 takes ownership of the multisig).
    • Member of SuperchainGuardianMultisig, SuperchainProxyAdminOwner.
    • Is a Guardian (acting via SuperchainGuardianMultisig).

    Used in:

    SuperchainGuardianMultisig 0x09f7…dAf2
    • This is a Gnosis Safe with 1 / 1 threshold. It uses the following modules: DeputyGuardianModule (allows the FoundationMultisig_2, called the deputy guardian, to act on behalf of the Gnosis Safe).
    • Can act as a Guardian.

    Used in:

    SuperchainGuardianMultisig participants (1) SecurityCouncilMultisig

    Those are the participants of the SuperchainGuardianMultisig.

    GnosisSafe 0x42d2…9c64
    • This is a Gnosis Safe with 2 / 2 threshold.
    • Member of FoundationMultisig_1, FoundationMultisig_2.

    Used in:

    GnosisSafe participants (2) 0xb237…97A50x4665…7429

    Those are the participants of the GnosisSafe.

    FoundationMultisig_1 0x847B…9D92
    • This is a Gnosis Safe with 5 / 7 threshold.
    • Member of SuperchainProxyAdminOwner.

    Used in:

    Those are the participants of the FoundationMultisig_1.

    BaseMultisig1 0x9855…46A1
    • This is a Gnosis Safe with 3 / 6 threshold.
    • Member of BaseAdminMultisig.

    Those are the participants of the BaseMultisig1.

    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):

    ProxyAdmin 0x0475…059E
    • Can be used to configure AddressManager - set and change address mappings.
    • Can be used to upgrade implementation of OptimismMintableERC20Factory, OptimismPortal, L2OutputOracle, L1ERC721Bridge, SystemConfig.
    • Can be used to upgrade implementation of L1StandardBridge - upgrading bridge implementation allows to access all funds and change every system component.

    A helper contract that generates OptimismMintableERC20 contracts on the network it’s deployed to. OptimismMintableERC20 is a standard extension of the base ERC20 token contract designed to allow the L1StandardBridge contracts to mint and burn tokens. This makes it possible to use an OptimismMintablERC20 as this chain’s representation of a token on the host chain, or vice-versa.

    Can be upgraded by:

    Upgrade delay: No delay

    Implementation used in:

    LivenessGuard 0x2442…4a25

    Implementation used in:

    The main entry point to deposit ERC20 tokens from host chain to this chain. This contract can store any token. This contract can store any token.

    Can be upgraded by:

    Upgrade delay: No delay

    Implementation used in:

    The main entry point to deposit funds from host chain to this chain. It also allows to prove and finalize withdrawals. This contract stores the following tokens: ETH.

    Can be upgraded by:

    Upgrade delay: No delay

    Implementation used in:

    SuperchainProxyAdmin 0x543b…fB04
    • Can be used to configure Lib_AddressManager - set and change address mappings.
    • Can be used to upgrade implementation of SuperchainConfig.

    Implementation used in:

    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

    Implementation used in:

    Used to bridge ERC-721 tokens from host chain to this chain.

    Can be upgraded by:

    Upgrade delay: No delay

    Implementation used in:

    Challenger1of2 0x6F8C…7824

    Can act as a Challenger.

    Contains configuration parameters such as the Sequencer address, gas limit on this chain and the unsafe block signer address.

    Can be upgraded by:

    Upgrade delay: No delay

    Implementation used in:

    Sends messages from host chain to this chain, and relays messages back onto host chain. In the event that a message sent from host chain to this chain is rejected for exceeding this chain’s epoch gas limit, it can be resubmitted via this contract’s replay function.

    Implementation used in:

    AddressManager 0x8EfB…BaE2

    Legacy contract used to manage a mapping of string names to addresses. Modern OP stack uses a different standard proxy system instead, but this contract is still necessary for backwards compatibility with several older contracts.

    Used to manage global configuration values for multiple OP Chains within a single Superchain network. The SuperchainConfig contract manages the PAUSED_SLOT, a boolean value indicating whether the Superchain is paused, and GUARDIAN_SLOT, the address of the guardian which can pause and unpause the system.

    Can be upgraded by:

    Upgrade delay: No delay

    Proxy used in:

    Escrow for custom external tokens that use the canonical bridge for messaging but are governed externally. This contract stores the following tokens: wstETH.

    Lib_AddressManager 0xdE1F…d81F

    Legacy contract used to manage a mapping of string names to addresses. Modern OP stack uses a different standard proxy system instead, but this contract is still necessary for backwards compatibility with several older contracts.

    Implementation used in:

    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

    Implementation used in:

    Main entry point for users depositing ETH.

    Can be upgraded by:

    Upgrade delay: No delay

    Implementation used in:

    wstETH Vault for custom wstETH Gateway. Fully controlled by Lido governance.

    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