Fraxtal logoFraxtal

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

$34.01 M

3.64%

Canonically Bridged
$34.01 M
Externally Bridged
$0.00
Natively Minted
$0.00
  • Tokens
  • Daily TPS
    0.10121.16%
  • 30D tx count
    132.14 K
  • Type
    Optimium
  • Purposes
    Universal, DeFi
  • ...

    ...

    Risk summary
    Fraud proof system is currently under development. Users need to trust the block proposer to submit correct L1 state roots.
    Risk analysis
    Fraud 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

    State validation

    In development

    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 upgrade since contracts are instantly upgradable.

    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.

    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 in development

    Ultimately, OP stack chains will use interactive fraud proofs to enforce state correctness. This feature is currently in development and the 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
    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
    3. Decentralizing the sequencer - OP Stack docs

    Users can force any transaction

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

    ProxyAdmin 0x13Fe…ABcA

    Owner of AddressManager. Admin of OptimismPortal, SystemConfig, L2OutputOracle, L1ERC721Bridge, L1StandardBridge.

    Sequencer 0x6017…d1f2

    Central actor allowed to commit L2 transactions to L1.

    Proposer 0xFb90…bc50

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

    Challenger 0xe0d7…0508

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

    Guardian 0xe0d7…0508

    Central actor allowed to pause deposits and withdrawals.

    FraxtalMultisig 0xe0d7…0508

    This address is the owner of the following contracts: ProxyAdmin, SystemConfig. It is also designated as a Guardian of the FraxchainPortal, meaning it can halt withdrawals. 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). This address is also the permissioned challenger of the system. It can delete non finalized roots without going through the fault proof process. This is a Gnosis Safe with 3 / 5 threshold.

    Those are the participants of the FraxtalMultisig.

    frxETHMultisig 0x8306…A81C

    This address is the owner of the gas token contract frxETH, and the frxETHMinter contract. It can pause and unpause ETH deposits, and change how much ETH is withheld from each submit() transaction. This is a Gnosis Safe with 3 / 5 threshold.

    Those are the participants of the frxETHMultisig.

    TimelockMultisig 0xB174…3f27

    This address is the owner of the timelock smart contract. It can queue, cancel, and execute transactions in the timelock (e.g., adding and removing frxETH whitelisted minters). This is a Gnosis Safe with 3 / 5 threshold.

    Those are the participants of the TimelockMultisig.

    Smart contracts

    The system consists of the following smart contracts:

    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: ProxyAdmin

    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, frxETH.

    Can be upgraded by: ProxyAdmin

    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: ProxyAdmin

    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: ProxyAdmin

    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: ProxyAdmin

    Upgrade delay: No delay

    The L1ERC721Bridge contract is the main entry point to deposit ERC721 tokens from L1 to L2.

    Can be upgraded by: ProxyAdmin

    Upgrade delay: No delay

    Fraxtal uses Frax Ether (frxETH) as the designated gas token, allowing users to utilize frxETH to pay for blockspace.

    frxETHMinter 0xbAFA…1138

    Authorized minter contract for frxETH, accepts user-supplied ETH and converts it to frxETH.

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

    Timelock 0x8412…39CA

    Allows for time-delayed execution of transactions in the FrxETH smart contract, such as adding and removing whitelisted minters. Delay is set to 2d.

    Upgradable contract that 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. The address of the guardian can only be modified by the ProxyAdmin by upgrading the SuperchainConfig contract. This contract is a fork of Optimism’s superchainConfig contract and may not be utilized by other chains.

    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: ProxyAdmin

    Upgrade delay: No delay

    Main entry point for users depositing ETH, frxETH.

    Can be upgraded by: ProxyAdmin

    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
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