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Fraxtal logoFraxtal

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Fraxtal is an EVM equivalent Optimium utilizing the OP stack as its smart contract platform and execution environment.


Value Locked
$270.65 M19.8%
Canonically Bridged
$266.94 M
Externally Bridged
$3.70 M
Natively Minted
$0.00

  • Tokens
  • Daily UOPS
    0.1492.9%
  • 30D tx count
    196.69 K

  • Type
    Optimium
  • Purpose
    Universal
  • Sequencer failureState validationData availabilityExit windowProposer failure

    Badges

    About

    Fraxtal is an EVM equivalent Optimium utilizing the OP stack as its smart contract platform and execution environment.


    Value Locked
    Activity
    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

    External

    Proof construction and state derivation rely fully on data that is NOT published on chain. Fraxtal uses a separate data availability module developed by the Frax Core Team, and data availability attestations are not published on chain.

    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.

    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

    Data required to compute fraud proof is not published on chain, and currently not publicly accessible

    Fraxtal uses a separate data availability module developed by the Frax Core Team. Data is posted off chain, and only hashes of blob data is published on an on chain inbox.

    • Funds can be lost if the data is not made available on the external provider (CRITICAL).

    • Funds can be lost if the sequencer posts an unavailable or malicious transaction root (CRITICAL).

    1. Fraxtal documentation
    2. On-Chain Inbox
    3. Derivation: Batch submission - OP Mainnet specs
    4. BatchInbox - Etherscan address
    5. OptimismPortal.sol - Etherscan source code, depositTransaction function
    Learn more about the DA layer here: FraxtalDA logoFraxtalDA
    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 FraxtalMultisig

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

    Guardian is an actor allowed to pause deposits and withdrawals.

    Proposer EOA 2

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

    Sequencer EOA 1

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

    FraxtalTimelockMultisig 0xB174…3f27
    • A Gnosis Safe with 3 / 5 threshold.
    • Can act on behalf of Timelock.
    • Can change the configuration of frxETH (acting via Timelock with 2d delay) - can add and remove frxETH minters and set a new timelock address.
    • Can change the configuration of frxETHMinter (acting via Timelock with 2d delay) - can withdraw all escrowed ETH, pause the contract and set user fees for minting frxETH (submit()).

    Those are the participants of the FraxtalTimelockMultisig.

    frxETHMinter 0xbAFA…1138
    • Can change the configuration of frxETH - can mint frxETH tokens.
    • Accepts user-supplied ETH and converts it to frxETH.
    FraxtalMultisig 0xe0d7…0508
    • 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 OptimismMintablePermitERC20Factory, SystemConfig, OptimismPortal, SuperchainConfig, L2OutputOracle, 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 FraxtalMultisig.

    frxETHMultisig 0x8306…A81C

    A Gnosis Safe with 4 / 7 threshold.

    Those are the participants of the frxETHMultisig.

    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):

    OptimismMintablePermitERC20Factory 0x11FE…76ccImplementation (Upgradable)Admin

    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

    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.

    ProxyAdmin 0x13Fe…ABcA
    • Can be used to configure AddressManager - set and change address mappings.
    • Can be used to upgrade implementation of OptimismMintablePermitERC20Factory, SystemConfig, OptimismPortal, SuperchainConfig, L2OutputOracle, L1ERC721Bridge.
    • Can be used to upgrade implementation of L1StandardBridge - upgrading the bridge implementation can give access to all funds escrowed therein.

    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

    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

    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, frxETH.

    Can be upgraded by:

    Upgrade delay: No delay

    frxETH token contract. Fraxtal uses Frax Ether as the designated gas token, allowing users to pay for blockspace with frxETH.

    This is NOT the shared SuperchainConfig contract of the OP stack Superchain but rather a local fork. It manages the PAUSED_SLOT, a boolean value indicating whether the local chain 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

    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

    Timelock 0x8412…39CA
    • Can be used to configure frxETH - can add and remove frxETH minters and set a new timelock address.
    • Can be used to configure frxETHMinter - can withdraw all escrowed ETH, pause the contract and set user fees for minting frxETH (submit()).
    • Allows for time-delayed execution of transactions. Current delay is 2d.
    AddressManager 0x8c5D…dABE

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

    Can be upgraded by:

    Upgrade delay: No delay

    Vault token contract (ERC-4626) for staked frxETH. The smart contract receives frxETH tokens and mints sfrxETH tokens.

    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, frxETH.

    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