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Blast is an EVM-compatible Optimistic Rollup supporting native yield. It invests funds deposited into the L1 bridge into various DeFi protocols transferring yield back to the L2.


Value Locked
Canonically Bridged
$5.78 M
Externally Bridged
$1.06 B
Natively Minted
$233.68 M

  • Tokens
  • Daily UOPS
    4.0232.1%
  • 30D ops count
    13.55 M

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

    Badges

    About

    Blast is an EVM-compatible Optimistic Rollup supporting native yield. It invests funds deposited into the L1 bridge into various DeFi protocols transferring yield back to the L2.


    Recategorisation

    179d
    11h
    27m
    58s

    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 here.

    Value Locked
    Canonical
    External
    Native
    Activity
    Blast
    Ethereum
    Onchain costs
    Calldata
    Blobs
    Compute
    Overhead
    Milestones & Incidents

    Blast Mainnet starts using blobs

    2024 May 27th

    Blast Mainnet starts publishing data to blobs.

    Learn more

    Blast upgrades to censor exploiter

    2024 Mar 26th

    The Munchables exploiter is prohibited from forcing transactions.

    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
    BlastBlast 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

    Node software 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. Once funds are added to the withdrawal queue, operator must ensure there is enough liquidity for withdrawals. If not, they need to reclaim tokens from Yield Providers.

    • Funds can lose value if there is a hack or the yield goes negative for yield providers (CRITICAL).

    • Funds can be frozen if there is not enough liquidity in the bridge, transactions are locked in withdrawal queue (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 BlastMultisig

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

    Guardian BlastMultisig

    Guardian is an actor allowed to pause deposits and withdrawals.

    Proposer EOA 1

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

    Sequencer EOA 2

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

    BlastMultisig 0x4f72…8B05
    • A Gnosis Safe with 3 / 5 threshold.
    • Can act on behalf of ProxyAdmin.
    • A Challenger.
    • Can change the configuration of SystemConfig - it can update the preconfer address, the batch submitter (Sequencer) address and the gas configuration of the system.
    • Can change the configuration of AddressManager (acting via ProxyAdmin) - set and change address mappings.
    • A Guardian.
    • Can upgrade the implementation of OptimismPortal, L1BlastBridge, SystemConfig, OptimismMintableERC20Factory, L2OutputOracle, ETHYieldManager, USDYieldManager, L1ERC721Bridge (acting via ProxyAdmin).
    • Can upgrade the implementation of L1StandardBridge (acting via ProxyAdmin) - upgrading the bridge implementation can give access to all funds escrowed therein.

    Those are the participants of the BlastMultisig.

    BridgeOwner 0x67CA…608C
    • A Gnosis Safe with 3 / 5 threshold.
    • Can upgrade the implementation of LaunchBridge.

    Those are the participants of the BridgeOwner.

    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):

    DSRYieldProvider 0x0733…81a8

    Yield Provider for DAI investing DAI into the MakerDAO DSR.

    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

    ProxyAdmin 0x3642…E883
    • Can be used to configure AddressManager - set and change address mappings.
    • Can be used to upgrade implementation of OptimismPortal, L1BlastBridge, SystemConfig, OptimismMintableERC20Factory, L2OutputOracle, ETHYieldManager, USDYieldManager, L1ERC721Bridge.
    • Can be used to upgrade implementation of L1StandardBridge - upgrading the bridge implementation can give access to all funds escrowed therein.

    Custom bridge gateway for Blast that allows the Operators to reinvest L1 tokens while they are bridged to the L2.

    Can be upgraded by:

    Upgrade delay: No delay

    LidoYieldProvider 0x4316…F7Db

    Yield Provider for ETH investing ETH into stETH.

    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

    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.

    This contract stores the following tokens: stETH.

    Can be upgraded by:

    Upgrade delay: No delay

    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

    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

    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

    Contract managing Yield Providers for ETH. This contract stores the following tokens: ETH, stETH.

    Can be upgraded by:

    Upgrade delay: No delay

    Contract escrowing stablecoins and managing Yield Providers for stablecoins (like for example DAI).

    Can be upgraded by:

    Upgrade delay: No delay

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

    Can be upgraded by:

    Upgrade delay: No delay

    AddressManager 0xE064…80C0

    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.

    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

    Escrow for ETH that is invested into a yield-bearing contracts such as stETH.

    Main entry point for users depositing ETH.

    Can be upgraded by:

    Upgrade delay: No delay

    Pre-launch Blast Vault that keeps stETH. Funds from this Vault can be migrated to Blast bridge.

    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