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SummaryValue SecuredActivityOnchain costsMilestones & IncidentsRisk summaryRisk analysisRollup stageTechnologyData availabilityState validationOperatorWithdrawalsPermissionsSmart contracts

Linea logoLinea

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About

Linea is a ZK Rollup powered by a zkEVM developed at Consensys, designed to scale the Ethereum network.

Value secured
$313.92 M6.06%
Canonically Bridged
$207.96 M
Natively Minted
$32.35 M
Externally Bridged
$73.60 M
View TVS Breakdown
  • Tokens
  • Past day UOPS
    0.995.75%
  • 30D ops count
    2.89 M
  • Gas token
    ETH
  • Stage
  • Type
    ZK Rollup
  • Purpose
    Universal
    • Sequencer failureState validationData availabilityExit windowProposer failure

    Badges

    About

    Linea is a ZK Rollup powered by a zkEVM developed at Consensys, designed to scale the Ethereum network.

    Recategorisation

    63d
    06h
    23m
    35s

    The project will be classified as "Other" due to its specific risks that set it apart from the standard classifications.

    The project will move to Others because:

    The proof system isn't fully functional

    Consequence: projects without a proper proof system fully rely on single entities to safely update the state. A malicious proposer can finalize an invalid state, which can cause loss of funds.

    Learn more about the recategorisation
    Value Secured

    2024 Apr 16 — 2025 Apr 16

    Total value securedTotal
    $313.92 M6.06%
    Canonically BridgedCanonically Bridged ValueCanonical
    $207.96 M6.74%
    Natively MintedNatively Minted TokensNative
    $32.35 M1.29%
    Externally BridgedExternally Bridged ValueExternal
    $73.60 M6.34%
    View TVS breakdown
    Activity

    2024 Apr 16 — 2025 Apr 15

    Onchain costs

    The section shows the operating costs that L2s pay to Ethereum.

    2024 Apr 16 — 2025 Apr 15

    1 year total cost
    $352.33 K
    Avg cost per L2 UOP
    $0.002679
    1 year data posted
    3.02 GiB
    Avg size per L2 UOP
    109.41 B
    Milestones & Incidents

    Linea starts using blobs

    2024 Mar 26th

    Linea starts publishing data to blobs.

    Learn more

    Alpha v2 is released

    2024 Feb 13th

    This release reduces L1 costs and fees for users.

    Learn more
    Risk summary
    The circuit of the program being proven is not public.

    Funds can be frozen if

    1. the sequencer refuses to include an exit transaction (CRITICAL),
    2. the operator censors withdrawal transaction.

    Users can be censored if

    1. the operator refuses to include their transactions.

    MEV can be extracted if

    1. the operator exploits their centralized position and frontruns user transactions.
    Risk analysis
    The circuit of the program being proven is not public.
    Sequencer failureState validationData availabilityExit windowProposer failure
    Sequencer failure
    No mechanism

    There is no mechanism to have transactions be included if the sequencer is down or censoring. Eventually (after 6 months of no finalized blocks) the Operator role becomes public, theoretically allowing anyone to post data.

    State validation
    ZK proofs (SN)

    SNARKs are zero knowledge proofs that ensure state correctness, but require trusted setup.

    Data availability
    Onchain

    All of the data needed for proof construction is published on Ethereum L1. Unlike most ZK rollups, transaction data is posted instead of state diffs.

    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. Eventually (after 6 months of no finalized blocks) the Operator role becomes public, theoretically allowing anyone to propose state with valid proofs.

    Rollup stageLineaLinea is a
    Stage 0
    ZK Rollup.
    There is no available node software that can reconstruct the state from L1 data, hence there is no way to verify that this system is a 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

    Validity proofs ensure state correctness

    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.

    Zero knowledge SNARK cryptography is used

    Despite their production use zkSNARKs 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 zkSNARKs require a trusted setup to operate.

    • Funds can be stolen if the cryptography is broken or implemented incorrectly.

    Data availability

    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. LineaRollup.sol - Etherscan source code, submitBlobs() function
    Learn more about the DA layer here: Ethereum logoEthereum
    State validation

    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.

    Prover Architecture

    The source code of the prover is currently not public.

    ZK Circuits

    The source code of the circuits is currently not public.

    • Funds can be stolen if the prover is able to generate false proofs.

    Verification Keys Generation

    Given that the circuit is not public, the generation of the verification keys is not public either.

    Operator

    The system has a centralized sequencer

    Only a trusted sequencer is allowed to submit transaction batches. A mechanism for users to submit their own batches is currently disabled.

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

    • Funds can be frozen if the sequencer refuses to include an exit transaction (CRITICAL).

    1. LineaRollup.sol - Etherscan source code, onlyRole(OPERATOR_ROLE) modifier

    Users can't force any transaction

    There is no general mechanism to force the sequencer to include the transaction.

    • Users can be censored if the operator refuses to include their transactions.

    Withdrawals

    Regular messaging

    The user initiates L2->L1 messages by submitting a regular transaction on this chain. When the block containing that transaction is settled, the message becomes available for processing on L1. ZK proofs are required to settle blocks. Note that withdrawal requests can be censored by the Sequencer. Currently, there is a general limit of 18750.0 ETH that can be withdrawn within each 1d time window. Users can (eventually, after 6 months of inactivity from the centralized Operator) exit by replacing the Operator. In such a case they need to self-propose and prove their new state on the base layer with the required software which is currently not made available.

    • Funds can be frozen if the operator censors withdrawal transaction.

    1. L1MessageService.sol - Etherscan source code, claimMessageWithProof() function
    2. LineaRollup.sol - Etherscan source code, setFallbackOperator() function
    Permissions

    Ethereum

    Roles:

    Operator (2) 0x46d2…9E3e0x52FF…6754

    Allowed to prove blocks and post the corresponding transaction data.

    Actors:

    CallForwardingProxy 0x3697…367D
    • A public proxy contract forwarding calls to a predefined target contract (LineaRollup). Can be called by any address.
    • Is allowed to interact with LineaRollup - submit and finalize blocks as the Operator role when 6 months of no finalizations have passed.
    Linea Multisig 0x892b…1DD3
    • A Multisig with 4/8 threshold. It uses the following modules: Roles (The Zodiac ‘Roles’ module for Safe multisigs allows defining roles that can call preconfigured targets on behalf of the Gnosis Safe).
    • Can act on behalf of L1Timelock.
    • Is allowed to interact with TokenBridge - manage all critical access control roles and permissions (full admin of the main bridge escrow).
    • Is allowed to interact with UpgradeableBeacon - change the beacon implementation.
    • Is allowed to interact with LineaRollup - manage all critical access control roles and permissions (full admin of the rollup system).
    • Is allowed to interact with L1Timelock - cancel queued transactions.
    • Is allowed to interact with L1Timelock - execute transactions that are ready.
    • Is allowed to interact with L1Timelock - manage all access control roles and change the minimum delay - acting via L1Timelock.
    • Is allowed to interact with L1Timelock - propose transactions.
    • Can upgrade the implementation of TokenBridge, LineaRollup - acting via ProxyAdmin, L1Timelock.

    Participants (8):

    0x4975…B6aB0x239d…aEFE0x12d6…bea90x5822…40AE0x9376…89920x4CB4…fAD40xab23…55A10xB4dA…dBcb
    Roles 0xF24f…d083
    • The Zodiac ‘Roles’ module for Safe multisigs allows defining roles that can call preconfigured targets on behalf of the Gnosis Safe.
    • Can act on behalf of Linea Multisig.
    • Is allowed to interact with TokenBridge - manage all critical access control roles and permissions (full admin of the main bridge escrow) - acting via Linea Multisig.
    • Is allowed to interact with UpgradeableBeacon - change the beacon implementation - acting via Linea Multisig.
    • Is allowed to interact with LineaRollup - manage all critical access control roles and permissions (full admin of the rollup system) - acting via Linea Multisig.
    • Is allowed to interact with L1Timelock - cancel queued transactions - acting via Linea Multisig.
    • Is allowed to interact with L1Timelock - execute transactions that are ready - acting via Linea Multisig.
    • Is allowed to interact with L1Timelock - manage all access control roles and change the minimum delay - acting via L1Timelock, Linea Multisig.
    • Is allowed to interact with L1Timelock - propose transactions - acting via Linea Multisig.
    • Can upgrade the implementation of TokenBridge, LineaRollup - acting via ProxyAdmin, L1Timelock, Linea Multisig.
    EOA 1 0x453B…bbA8

    Is allowed to interact with Roles - pause the TokenBridge, the USDCBridge and the core functionalities of the system (via Roles module, LineaRollup contract).

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

    Ethereum

    TokenBridge 0x051F…3319Implementation (Upgradable)Admin

    Contract used to bridge and escrow ERC-20 tokens. This contract can store any token.

    Can be upgraded by:
    Linea Multisig with no delayRoles with no delay
    BridgedToken 0x36f2…3763

    Standard implementation used for assets that are native to the Linea L2 and bridged back to ethereum.

    UpgradeableBeacon 0x971f…7DeB

    A beacon with an upgradeable implementation currently set as BridgedToken. Beacon proxy contracts pointing to this beacon will all use its implementation.

    PlonkVerifierForMultiTypeDataAggregation 0xBfF4…fe6F

    Smart contract used to verify the proofs of Linea zkEVM execution.

    LineaRollup 0xd19d…876FImplementation (Upgradable)Admin

    The main contract of the Linea zkEVM rollup. Contains state roots, the verifier addresses and manages messages between L1 and the L2. This contract stores the following tokens: ETH.

    Can be upgraded by:
    Linea Multisig with no delayRoles with no delay
    L1Timelock 0xd6B9…0574
    • A standard timelock with access control. The current minimum delay is 0s.
    • Can act on behalf of ProxyAdmin.
    • Can be used to interact with L1Timelock - manage all access control roles and change the minimum delay.
    ProxyAdmin 0xF505…66d6

    Can be used to upgrade implementation of TokenBridge, LineaRollup.

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

    The current deployment carries some associated risks:

    • Funds can be stolen if a contract receives a malicious code upgrade. There is a 0s delay on code upgrades.