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Xterio Chain

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Xterio Chain is an OP stack Optimium on Ethereum. The chain focuses on gaming, high performance and low fees .


  • Total Value SecuredTVS
    $684.463.04%
  • Past day UOPSDaily UOPS
    No data
  • Gas token
    ETH
  • Type
    Other

  • Purposes
    Universal, Gaming
  • Chain ID
    2702128

  • Tokens breakdown

    Sequencer failureState validationData availabilityExit windowProposer failure

    Badges

    About

    Xterio Chain is an OP stack Optimium on Ethereum. The chain focuses on gaming, high performance and low fees .

    Why is the project listed in others?

    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.

    There is no data availability bridge

    Consequence: projects without a data availability bridge fully rely on single entities (the sequencer) to honestly rely available data roots on Ethereum. A malicious sequencer can collude with the proposer to finalize an unavailable state, which can cause loss of funds.

    Learn more about the recategorisation here.


    Total
    Canonically BridgedCanonically Bridged ValueCanonical
    Natively MintedNatively Minted TokensNative
    Externally BridgedExternally Bridged ValueExternal

    ETH & derivatives
    Stablecoins
    BTC & derivatives
    Other
    Past Day UOPS
    Past Day Ops count
    Max. UOPS
    Past day UOPS/TPS Ratio

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



    Total cost
    Avg cost per L2 UOP
    Avg cost per day

    Deposited/Forced transactions are disabled, a permissioned admin can withdraw all ETH. Xterio chain on ethereum is sunset and funds are being transferred to Xterio Chain (BNB).
    Sequencer failureState validationData availabilityExit windowProposer failure
    Sequencer failure
    Self sequence

    In the event of a sequencerA party responsible for ordering and executing transactions on the rollup. The sequencer verifies transactions, compresses the data into a block, and submits the data related to it to enable state reconstruction to Ethereum L1 as a single transaction. The data can be either transaction data or state diffs. failure, users can force transactions to be included in the project’s chain by sending them to L1Layer 1 (L1) is a blockchain that is self-reliant on its validator set for its security and consensus properties. Ethereum is an example of a layer 1. Blockchains started receiving the moniker of layer 1 once layer 2 became a meaningful area of development.. There can be up to a 12h delay on this operation.

    State validation
    None

    Currently the system permits invalid state rootsA cryptographic hash succinctly representing a state using a Merkle tree.. More details in project overview.

    Data availability
    External

    Proof construction and state derivation rely fully on data that is NOT published onchain. A custom data availabilityThe property of a rollup's data being reachable by any node retrieving the data that were rolled up and executed to reach the proposed state. Data availability (DA), specifically decoupling it from the rollup nodes themselves, is one of the preeminent factors which allows a rollup to scale securely. A rollup is faced with a decision of what to use as a DA layer to guarantee that any node can retrieve this data--permissionlessly under any circumstance. For this reason, using Ethereum for DA currently provides the strongest security guarantees. If data is stored somewhere other than a permissionless L1, then the project is not a rollup, but rather a validium or an optimium. (DA) provider without attestations is used, but data unavailability can be challenged.

    Exit window
    None

    There is no window for users to exit in case of an unwanted upgrade since contracts are instantly upgradable.

    Proposer failure
    Cannot withdraw

    Only the whitelisted proposers can publish state rootsA cryptographic hash succinctly representing a state using a Merkle tree. on L1Layer 1 (L1) is a blockchain that is self-reliant on its validator set for its security and consensus properties. Ethereum is an example of a layer 1. Blockchains started receiving the moniker of layer 1 once layer 2 became a meaningful area of development., so in the event of failure the withdrawals are frozen.

    Xterio Chain
    Xterio Chain is not even a
    Stage 0
    project.
    The requirement for available nodeA software client that participates in the network. software is under review.

    Learn more about Stages
    Please keep in mind that these stages do not reflect project security, this is an opinionated assessment of project 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.

    XterioDA is a data availabilityThe property of a rollup's data being reachable by any node retrieving the data that were rolled up and executed to reach the proposed state. Data availability (DA), specifically decoupling it from the rollup nodes themselves, is one of the preeminent factors which allows a rollup to scale securely. A rollup is faced with a decision of what to use as a DA layer to guarantee that any node can retrieve this data--permissionlessly under any circumstance. For this reason, using Ethereum for DA currently provides the strongest security guarantees. If data is stored somewhere other than a permissionless L1, then the project is not a rollup, but rather a validium or an optimium. solution using data availability challenges (DA Challenges).

    Economic security
    DA Challenges

    There are no onchain assets at risk of being slashed in case of a data withholding attack. However, there is a mechanism that allows users to challenge unavailability of data. The system is not secure if the malicious sequencerA party responsible for ordering and executing transactions on the rollup. The sequencer verifies transactions, compresses the data into a block, and submits the data related to it to enable state reconstruction to Ethereum L1 as a single transaction. The data can be either transaction data or state diffs. is able to outspend the altruistic challengers, and there is no pool of funds onchain to incentivize challengers.

    Fraud detection
    None

    There is no fraud detection mechanism in place. A data withholding attack can only be detected by nodes downloading the full data from the DA layerAn infrastructure that is used to make publish data so that it's available to the public. They take the form of Data Availability Committees (DACs) or blockchains. Not to confuse with the layer responsible with ordering, since ordering and DA can be separated..

    Committee security
    None

    The committee does not meet basic security standards, either due to insufficient size, lack of member diversity, or poorly defined threshold parameters. The system lacks an effective DA bridgeSystem that verifies that data has been made available. It takes the form of a smart contract verifying a consensus or, if the data is verified directly by either downloading the full data or sampling, of an enshrined bridge. and it is reliant on the assumption of an honest sequencerA party responsible for ordering and executing transactions on the rollup. The sequencer verifies transactions, compresses the data into a block, and submits the data related to it to enable state reconstruction to Ethereum L1 as a single transaction. The data can be either transaction data or state diffs., creating significant risks to data integrity and availability.

    Upgradeability
    No delay

    There is no delay in the upgradeabilityThe ability for rollup smart contracts and parameters used in a rollup to be updated by holders of an admin key. Upgradeability represents a vector of risk for users, and should be decentralized and combined with time delays for greater security guarantees. of the bridgeA message-passing protocol between two blockchains. At its most basic, a token bridge consists of a smart contract which can escrow funds on one side of the bridge, and instruct the release or minting of corresponding assets on the other side, but bridges could also support arbitrary messages. How these instructions are validated is a critical factor in assessing the trust assumptions of a bridge.. Users have no time to exit the system before the bridge implementation update is completed.

    Relayer failure
    No mechanism

    The relayer role is permissioned, and the DA bridgeSystem that verifies that data has been made available. It takes the form of a smart contract verifying a consensus or, if the data is verified directly by either downloading the full data or sampling, of an enshrined bridge. does not have a Security CouncilA Security Council is a sufficiently decentralized set of members that is able to upgrade a system. A properly set up Security Council consists of at least 8 members with a threshold greater than 75%. What 'sufficiently decentralized' means is fundamentally subjective and L2BEAT evaluates each case individually. A Security Council is allowed to instantly upgrade Stage 1 rollups. or a governance mechanism to propose new relayers. In case of relayer failure, the DA bridge will halt and be unable to recover without the intervention of a centralized entity.

    Architecture

    XterioDA layer

    Data AvailabilityThe property of a rollup's data being reachable by any node retrieving the data that were rolled up and executed to reach the proposed state. Data availability (DA), specifically decoupling it from the rollup nodes themselves, is one of the preeminent factors which allows a rollup to scale securely. A rollup is faced with a decision of what to use as a DA layer to guarantee that any node can retrieve this data--permissionlessly under any circumstance. For this reason, using Ethereum for DA currently provides the strongest security guarantees. If data is stored somewhere other than a permissionless L1, then the project is not a rollup, but rather a validium or an optimium. Challenges

    Xterio relies on DA challenges for data availability. The DA Provider submits an input commitment on Ethereum, and users can request the data behind the commitment off-chain from the DA Provider. If a DA challenger finds that the data behind a tx data commitment is not available, they can submit a challenge which requires locking a bond within 12h. A challenge can be resolved by publishing the preimage data within an additional 12h. In such case, a portion of the challenger bond is burned, with the exact amount estimated as the cost incurred by the resolver to publish the full data, meaning that the resolver and challenger will approximately lose the same amount of funds. The system is not secure if the malicious sequencerA party responsible for ordering and executing transactions on the rollup. The sequencer verifies transactions, compresses the data into a block, and submits the data related to it to enable state reconstruction to Ethereum L1 as a single transaction. The data can be either transaction data or state diffs. is able to outspend the altruistic challengers. If instead, after a challenge, the preimage data is not published, the chain reorgs to the last fully derivable state.

    DA BridgeSystem that verifies that data has been made available. It takes the form of a smart contract verifying a consensus or, if the data is verified directly by either downloading the full data or sampling, of an enshrined bridge.

    Only hashes of data batches are posted as DA commitments to an EOA on Ethereum. However, there is a mechanism that allows users to challenge unavailability of data.

    • Funds can be lost if the sequencer posts an invalid data availability certificate and there are no challengers.

    • Funds can be lost if the sequencer posts an invalid data availability certificate, and he is able to outspend the challengers.

    1. Alt-DA Specification
    2. Security Considerations - Ethresear.ch
    No state validation

    OP Stack projects can use the OP fault proof systemThe infrastructure that allows projects to verify their state transitions. It is composed by onchain verifiers and offchain provers. The main two flavors are optimistic and ZK proof systems, but they can be combined in a hybrid model. In general though, if a system is able to accept state roots optimistically, even if it has a ZK component, it is considered an optimistic 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 ProposerIn the context of L2s, the actor that proposes a claimed state root on L1. The term is also used in the context of Ethereum to refer to the actor that proposes a new block. and Challengers to ensure state correctness. The smart contract system permits invalid state rootsA cryptographic hash succinctly representing a state using a Merkle tree..

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

    1. L2OutputOracle.sol - source code, deleteL2Outputs function

    Past upgrades

    The metrics include upgrades on the currently used proxy contracts. Historical proxy contracts and changes of such are not included.

    Count of upgrades
    3
    Last upgrade
    1y 5mo ago
    Avg upgrade interval
    11mo 13d
    2025 July 14, 12:46 UTC
    13changes

    Discovery rerun on the same block number with only config-related changes.

    New and verified contracts

    + Status: CREATED
    contract DataAvailabilityChallenge (0x16193e14197c10109F3e81b938153A04A2a00190)
    +++ description: The DataAvailabilityChallenge contract is used to challenge the full availability of data behind commimted transaction data hashes. See the technology section for more details.
    + Status: CREATED
    contract L1ERC721Bridge (0x28d56C3BBbe4807c19Cc81E6D5207Fb681C3726b)
    +++ description: Used to bridge ERC-721 tokens from host chain to this chain.
    + Status: CREATED
    contract L1StandardBridge (0x2AD84AbD52050956AcC9c490D024b821A59e3FB6)
    +++ description: The main entry point to deposit ERC20 tokens from host chain to this chain.
    + Status: CREATED
    contract OptimismMintableERC20Factory (0x515A0c8b1d9574C65EA1924eCd767B1d9b6AC32f)
    +++ description: 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 OptimismMintableERC20 as this chain's representation of a token on the host chain, or vice-versa.
    + Status: CREATED
    contract L2OutputOracle (0x5A0492D20D984eE904E46E6Ff24572bc755abb28)
    +++ description: 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.
    + Status: CREATED
    contract SystemConfig (0x6E99cdE188DAAFeEcb6eD8AC28B98dE4c8eE5D6C)
    +++ description: Contains configuration parameters such as the Sequencer address, gas limit on this chain and the unsafe block signer address.
    + Status: CREATED
    contract L1CrossDomainMessenger (0x702dF90E92A6841c9013faE6D724ddFA8F141d5C)
    +++ description: 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.
    + Status: CREATED
    contract Safe (0x8f33C32503B860eDd31BeC1c80669aFee40901f3)
    +++ description: None
    + Status: CREATED
    contract ProxyAdmin (0x9e48d6bBca781c23392Ec459BfB3657C40a794A8)
    +++ description: None
    + Status: CREATED
    contract OptimismPortal (0xBC2bEDA4ce7A1f40aa458322A33B44081b2F545A)
    +++ description: The main entry point to deposit funds from host chain to this chain. It also allows to prove and finalize withdrawals. Forced transactions from Layer 1 are disabled.
    + Status: CREATED
    contract AddressManager (0xBdF852e2cc26Ea3C2dee7b493B1Fc12dA406175a)
    +++ description: 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.
    + Status: CREATED
    contract SuperchainConfig (0xcbF423525a5471Fc5037a5397F99f6F09fe41379)
    +++ description: 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.
    + Status: CREATED
    contract Xterio Multisig (0xfF75Bd7672b79f2562fAf98D488bbb3Db1cD1574)
    +++ description: None
    2025 April 18, 18:48 UTC
    High severity
    18changes

    upgrade to 'special' OptiPortal without deposited tx mechanism and with a permissioned withdrawEth function.

    contract OptimismPortal (0xBC2bEDA4ce7A1f40aa458322A33B44081b2F545A) {
    +++ description: The main entry point to deposit funds from host chain to this chain. It also allows to prove and finalize withdrawals. Forced transactions from Layer 1 are disabled.
    template:
    - "opstack/OptimismPortal"
    + "opstack/OptimismPortalAdminWithdraw"
    sourceHashes.1:
    - "0xe35fb7bc0433439337b3eadda3d6fb7991918162f62a337a695e8c7f948cdd35"
    + "0x106b0e020294fd04557c64727796c1a7afc80dba9c83e38e52b5282d4d1531f5"
    description:
    - "The main entry point to deposit funds from host chain to this chain. It also allows to prove and finalize withdrawals."
    + "The main entry point to deposit funds from host chain to this chain. It also allows to prove and finalize withdrawals. Forced transactions from Layer 1 are disabled."
    issuedPermissions.2:
    + {"permission":"upgrade","to":"0xfF75Bd7672b79f2562fAf98D488bbb3Db1cD1574","via":[{"address":"0x9e48d6bBca781c23392Ec459BfB3657C40a794A8"}]}
    issuedPermissions.1.permission:
    - "upgrade"
    + "guard"
    issuedPermissions.1.to:
    - "0xfF75Bd7672b79f2562fAf98D488bbb3Db1cD1574"
    + "0xdF3700a9Cf9c7506Ca3B41E6ba991476677A8787"
    issuedPermissions.1.via.0:
    - {"address":"0x9e48d6bBca781c23392Ec459BfB3657C40a794A8"}
    issuedPermissions.0.permission:
    - "guard"
    + "interact"
    issuedPermissions.0.to:
    - "0xdF3700a9Cf9c7506Ca3B41E6ba991476677A8787"
    + "0x8f33C32503B860eDd31BeC1c80669aFee40901f3"
    issuedPermissions.0.description:
    + "withdraw all ETH without proof."
    values.$implementation:
    - "0xb6a5DCc244EfAbE3194cf5e5590a463f44eD5784"
    + "0xEdE953bab7C50B2e5150316Ae0574F0cbA4068a9"
    values.$pastUpgrades.1:
    + ["2024-05-24T08:53:23.000Z","0xc93dc2274b4ce4975aae8b5d6ffde3b52c6457d4c11400d710a63142d369fa83",["0xb6a5DCc244EfAbE3194cf5e5590a463f44eD5784"]]
    values.$pastUpgrades.0.2:
    - "0xc93dc2274b4ce4975aae8b5d6ffde3b52c6457d4c11400d710a63142d369fa83"
    + ["0xEdE953bab7C50B2e5150316Ae0574F0cbA4068a9"]
    values.$pastUpgrades.0.1:
    - "2024-05-24T08:53:23.000Z"
    + "0x28fc02b17e9d4fc1107f498afbce93158b39649d34acf6f709626e3a326037ad"
    values.$pastUpgrades.0.0:
    - ["0xb6a5DCc244EfAbE3194cf5e5590a463f44eD5784"]
    + "2025-04-16T15:34:35.000Z"
    values.$upgradeCount:
    - 1
    + 2
    values.privilegedAddress:
    + "0x8f33C32503B860eDd31BeC1c80669aFee40901f3"
    }
    + Status: CREATED
    contract Safe (0x8f33C32503B860eDd31BeC1c80669aFee40901f3)
    +++ description: None
    2025 April 06, 08:20 UTC
    High severity
    14changes

    Operators change, no change to implementations.

    contract L2OutputOracle (0x5A0492D20D984eE904E46E6Ff24572bc755abb28) {
    +++ description: 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.
    issuedPermissions.1.permission:
    - "propose"
    + "challenge"
    issuedPermissions.1.to:
    - "0x7d2f9b38866141Bf090DD670A826F27eA2408Ad4"
    + "0x8b3B4F6C348f6baC39190B89c801E61E41F05b88"
    issuedPermissions.0.permission:
    - "challenge"
    + "propose"
    issuedPermissions.0.to:
    - "0xfA8d42bDE52C2B8B05fE5EeCbAdEa6CB698A0Bc5"
    + "0xE4Cb2fd9E409ABE977EC946D54b59034C39AB07D"
    values.$pastUpgrades.2:
    + ["2025-04-05T14:16:59.000Z","0x3c36d0fd57e70dee54e8ecc5c70de812a57dd8bc3db576cf12ce164acbeb8cce",["0xA9D78F579f1B30194F3c2Ca1987A9B91A33BDF08"]]
    values.$pastUpgrades.1:
    + ["2025-04-05T14:25:47.000Z","0x4dbaa9a0411962209ad663ec973dca85671030aef9bbf598b9727a292a83525d",["0x48Ef83Cf812f291EDB00C2D48440Ee90cD12be1a"]]
    values.$upgradeCount:
    - 1
    + 3
    +++ severity: HIGH
    values.challenger:
    - "0xfA8d42bDE52C2B8B05fE5EeCbAdEa6CB698A0Bc5"
    + "0x8b3B4F6C348f6baC39190B89c801E61E41F05b88"
    values.CHALLENGER:
    - "0xfA8d42bDE52C2B8B05fE5EeCbAdEa6CB698A0Bc5"
    + "0x8b3B4F6C348f6baC39190B89c801E61E41F05b88"
    +++ severity: HIGH
    values.proposer:
    - "0x7d2f9b38866141Bf090DD670A826F27eA2408Ad4"
    + "0xE4Cb2fd9E409ABE977EC946D54b59034C39AB07D"
    values.PROPOSER:
    - "0x7d2f9b38866141Bf090DD670A826F27eA2408Ad4"
    + "0xE4Cb2fd9E409ABE977EC946D54b59034C39AB07D"
    }
    contract SystemConfig (0x6E99cdE188DAAFeEcb6eD8AC28B98dE4c8eE5D6C) {
    +++ description: Contains configuration parameters such as the Sequencer address, gas limit on this chain and the unsafe block signer address.
    issuedPermissions.1.to:
    - "0x7d6251D49A102a330CfB46d132982781620700Cb"
    + "0x39857a92E26648438d9c7dDDa1Ee3e481dea54B3"
    values.batcherHash:
    - "0x7d6251D49A102a330CfB46d132982781620700Cb"
    + "0x39857a92E26648438d9c7dDDa1Ee3e481dea54B3"
    values.unsafeBlockSigner:
    - "0xcbdD38Ce74BA96F0ae3D2E608DA96Ec744c80A7E"
    + "0x7a4e92aD7E40C8df264eD18010847e6C27AB3d82"
    }
    2024 July 18, 14:50 UTC
    18changes

    Provide description of changes. This section will be preserved.

    Initial discovery

    + Status: CREATED
    contract PreimageOracle (0x089A4754538B74Ff63Bc6AbeaD7A95973aB03572)
    +++ description: None
    + Status: CREATED
    contract DelayedWETH (0x0eCe16401A80551345bB672f177f51A8755FF775)
    +++ description: None
    + Status: CREATED
    contract PermissionedDisputeGame (0x15b689D90a62C3F7380054C8867b7e7f17Fa7F4B)
    +++ description: None
    + Status: CREATED
    contract DataAvailabilityChallenge (0x16193e14197c10109F3e81b938153A04A2a00190)
    +++ description: None
    + Status: CREATED
    contract MIPS (0x253DdBb3549e0CEFaaaA7f71BE502C5b94771dDc)
    +++ description: None
    + Status: CREATED
    contract L1ERC721Bridge (0x28d56C3BBbe4807c19Cc81E6D5207Fb681C3726b)
    +++ description: Used to bridge ERC-721 tokens from host chain to this chain.
    + Status: CREATED
    contract L1StandardBridge (0x2AD84AbD52050956AcC9c490D024b821A59e3FB6)
    +++ description: The main entry point to deposit ERC20 tokens from host chain to this chain. This contract can store any token.
    + Status: CREATED
    contract DisputeGameFactory (0x443164F044D8840479234e00E7aD5bb06b85fC78)
    +++ description: None
    + Status: CREATED
    contract OptimismMintableERC20Factory (0x515A0c8b1d9574C65EA1924eCd767B1d9b6AC32f)
    +++ description: None
    + Status: CREATED
    contract FaultDisputeGame (0x56c7D88ee46BfD6cab37508E2e39e985a68007a4)
    +++ description: None
    + Status: CREATED
    contract L2OutputOracle (0x5A0492D20D984eE904E46E6Ff24572bc755abb28)
    +++ description: 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.
    + Status: CREATED
    contract SystemConfig (0x6E99cdE188DAAFeEcb6eD8AC28B98dE4c8eE5D6C)
    +++ description: Contains configuration parameters such as the Sequencer address, gas limit on this chain and the unsafe block signer address.
    + Status: CREATED
    contract L1CrossDomainMessenger (0x702dF90E92A6841c9013faE6D724ddFA8F141d5C)
    +++ description: 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.
    + Status: CREATED
    contract ProxyAdmin (0x9e48d6bBca781c23392Ec459BfB3657C40a794A8)
    +++ description: None
    + Status: CREATED
    contract OptimismPortal (0xBC2bEDA4ce7A1f40aa458322A33B44081b2F545A)
    +++ description: The main entry point to deposit funds from host chain to this chain. It also allows to prove and finalize withdrawals.
    + Status: CREATED
    contract AddressManager (0xBdF852e2cc26Ea3C2dee7b493B1Fc12dA406175a)
    +++ description: None
    + Status: CREATED
    contract SuperchainConfig (0xcbF423525a5471Fc5037a5397F99f6F09fe41379)
    +++ description: None
    + Status: CREATED
    contract RollupOwnerMultisig (0xfF75Bd7672b79f2562fAf98D488bbb3Db1cD1574)
    +++ description: None

    The system has a centralized operator

    The operatorAn operator is the entity charged with managing a rollup and progressing its state. A rollup operator can be a centralized sequencer, proposer, prover, challenger, pauser of admin that is able to perform upgrades. is the only entity that can propose blocksAn ordered list of transactions and chain-related metadata that gets bundled together and published to the L1/DA layer. Nodes execute the transactions contained within blocks to change the rollup chain’s state. Protocol rules dictate what constitutes a valid block, and invalid blocks are skipped over.. 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 - source code, CHALLENGER address
    2. L2OutputOracle.sol - 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 - source code, depositTransaction function

    Regular messaging

    The user initiates L2Layer 2 (L2) is a category of technical solutions aimed to scale the base layer in a trust minimized way. This category includes solutions like rollups as well as state channels and plasma. Other solutions are able to scale further, but with the introduction of additional trust assumptions, which are therefore not trust minimized. Sometimes the term Layer 2 is used to refer to include these solutions too, like validiums and optimiums, but to distinguish between trust minimized and non trust minimized solutions they are often referred to as "light" L2s, opposed to "strong" L2s like rollups.->L1Layer 1 (L1) is a blockchain that is self-reliant on its validator set for its security and consensus properties. Ethereum is an example of a layer 1. Blockchains started receiving the moniker of layer 1 once layer 2 became a meaningful area of development. messages by submitting a regular transaction on this chain. When the blockAn ordered list of transactions and chain-related metadata that gets bundled together and published to the L1/DA layer. Nodes execute the transactions contained within blocks to change the rollup chain’s state. Protocol rules dictate what constitutes a valid block, and invalid blocks are skipped over. containing that transaction is settled, the message becomes available for processing on L1. The process of block finalization takes a challenge periodIn optimistic rollups, the window of time wherein network participants can assert that some fraud was included in a prior block. Most optimistic rollups currently specify a challenge window of 7 days. By extending the period, there is more time for participants to guard against fraud (invalid state transitions), but also more time until withdrawals gets enabled. of 7d to complete.

    • 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 - source code, proveWithdrawalTransaction function
    2. OptimismPortal.sol - source code, finalizeWithdrawalTransaction function
    3. L2OutputOracle.sol - source code, PROPOSER check

    Forced messaging

    If the user experiences censorship from the operatorAn operator is the entity charged with managing a rollup and progressing its state. A rollup operator can be a centralized sequencer, proposer, prover, challenger, pauser of admin that is able to perform upgrades. with regular L2Layer 2 (L2) is a category of technical solutions aimed to scale the base layer in a trust minimized way. This category includes solutions like rollups as well as state channels and plasma. Other solutions are able to scale further, but with the introduction of additional trust assumptions, which are therefore not trust minimized. Sometimes the term Layer 2 is used to refer to include these solutions too, like validiums and optimiums, but to distinguish between trust minimized and non trust minimized solutions they are often referred to as "light" L2s, opposed to "strong" L2s like rollups.->L1Layer 1 (L1) is a blockchain that is self-reliant on its validator set for its security and consensus properties. Ethereum is an example of a layer 1. Blockchains started receiving the moniker of layer 1 once layer 2 became a meaningful area of development. messaging they can submit their messages directly on L1. The system is then obliged to service this request or halt all messages, including forced withdrawals from L1 and regular messages initiated on L2. Once the force operation is submitted and if the request is serviced, the operation follows the flow of a regular message.

    1. Forced withdrawal from an OP Stack blockchain

    EVM compatible smart contracts are supported

    OP stack chains are pursuing the EVM EquivalenceA perfect degree of compatibility; where one system or concept is indistinguishable from another in the domain being compared. In the context of rollups, it generally refers to the proximity to the EVM and to Ethereum architecture. model. No changes to smart contracts are required regardless of the language they are written in, i.e. anything deployed on L1Layer 1 (L1) is a blockchain that is self-reliant on its validator set for its security and consensus properties. Ethereum is an example of a layer 1. Blockchains started receiving the moniker of layer 1 once layer 2 became a meaningful area of development. can be deployed on L2Layer 2 (L2) is a category of technical solutions aimed to scale the base layer in a trust minimized way. This category includes solutions like rollups as well as state channels and plasma. Other solutions are able to scale further, but with the introduction of additional trust assumptions, which are therefore not trust minimized. Sometimes the term Layer 2 is used to refer to include these solutions too, like validiums and optimiums, but to distinguish between trust minimized and non trust minimized solutions they are often referred to as "light" L2s, opposed to "strong" L2s like rollups..

    1. Introducing EVM Equivalence
    A dashboard to explore contracts and permissions
    Go to Disco
    Disco UI Banner

    Ethereum

    Actors:

    Xterio Multisig0xfF75…1574

    A Multisig with 3/4 threshold.

    • Can upgrade with no delay
      • DataAvailabilityChallenge
      • L1ERC721Bridge
      • L1StandardBridge
      • OptimismMintableERC20Factory
      • L2OutputOracle
      • SystemConfig
      • L1CrossDomainMessenger
      • OptimismPortal
      • SuperchainConfig
    • Can interact with AddressManager
      • set and change address mappings

    A Multisig with 3/4 threshold.

    • Can interact with OptimismPortal
      • withdraw all ETH without proof
    • Can interact with OptimismPortal
      • Allowed to pause withdrawals. In op stack systems with a proof systemThe infrastructure that allows projects to verify their state transitions. It is composed by onchain verifiers and offchain provers. The main two flavors are optimistic and ZK proof systems, but they can be combined in a hybrid model. In general though, if a system is able to accept state roots optimistically, even if it has a ZK component, it is considered an optimistic proof system., the Guardian can also blacklist dispute games and set the respected game type (permissioned / permissionlessAnyone willing should be able to join and leave the network at any time, without causing significant disturbance to the network or being detrimental to the party in question. No single entity should have the power to allowlist or blocklist participants.)
    • Can interact with SuperchainConfig
      • Allowed to pause withdrawals. In op stack systems with a proof system, the Guardian can also blacklist dispute games and set the respected game type (permissioned / permissionless)
    • Can interact with L2OutputOracle
      • Allowed to challenge or delete state rootsA cryptographic hash succinctly representing a state using a Merkle tree. proposed by a ProposerIn the context of L2s, the actor that proposes a claimed state root on L1. The term is also used in the context of Ethereum to refer to the actor that proposes a new block.
    • Can interact with DataAvailabilityChallenge
      • can upgrade the parameters of DA challenges like the bond size or refund percentages, potentially making challenges infeasable or insecure
    • Can interact with SystemConfig
      • it can update the preconfer address, the batch submitter (SequencerA party responsible for ordering and executing transactions on the rollup. The sequencer verifies transactions, compresses the data into a block, and submits the data related to it to enable state reconstruction to Ethereum L1 as a single transaction. The data can be either transaction data or state diffs.) address and the gasA virtual fuel used to execute smart contracts on a rollup. The EVM (or other VM within the rollup) uses an accounting mechanism to correspond the consumption of gas to the consumption of computing resources, and to limit the consumption of computing resources. configuration of the system
    • Can interact with L2OutputOracle
      • Allowed to post new state rootsA cryptographic hash succinctly representing a state using a Merkle tree. of the current layer to the host chain
    • Can interact with SystemConfig
      • Allowed to commit transactions from the current layer to the host chain
    A dashboard to explore contracts and permissions
    Go to Disco
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    A diagram of the smart contract architecture
    A diagram of the smart contract architecture

    Ethereum

    The DataAvailabilityChallenge contract is used to challenge the full availability of data behind commimted transaction data hashes. See the technology section for more details.

    • Roles:
      • admin: ProxyAdmin; ultimately Xterio Multisig
      • owner: EOA 3

    Contains a list of proposed state rootsA cryptographic hash succinctly representing a state using a Merkle tree. which Proposers assert to be a result of blockAn ordered list of transactions and chain-related metadata that gets bundled together and published to the L1/DA layer. Nodes execute the transactions contained within blocks to change the rollup chain’s state. Protocol rules dictate what constitutes a valid block, and invalid blocks are skipped over. execution. Currently only the PROPOSERIn the context of L2s, the actor that proposes a claimed state root on L1. The term is also used in the context of Ethereum to refer to the actor that proposes a new block. address can submit new state roots.

    • Roles:
      • admin: ProxyAdmin; ultimately Xterio Multisig
      • challenger: EOA 2
      • proposer: EOA 4

    Contains configuration parameters such as the SequencerA party responsible for ordering and executing transactions on the rollup. The sequencer verifies transactions, compresses the data into a block, and submits the data related to it to enable state reconstruction to Ethereum L1 as a single transaction. The data can be either transaction data or state diffs. address, gas limitThe maximum amount of gas a transaction or block may consume. on this chain and the unsafe blockAn ordered list of transactions and chain-related metadata that gets bundled together and published to the L1/DA layer. Nodes execute the transactions contained within blocks to change the rollup chain’s state. Protocol rules dictate what constitutes a valid block, and invalid blocks are skipped over. signer address.

    • Roles:
      • admin: ProxyAdmin; ultimately Xterio Multisig
      • batcherHash: EOA 5
      • owner: EOA 3

    The main entry point to deposit funds from host chain to this chain. It also allows to prove and finalize withdrawals. Forced transactions from Layer 1Layer 1 (L1) is a blockchain that is self-reliant on its validator set for its security and consensus properties. Ethereum is an example of a layer 1. Blockchains started receiving the moniker of layer 1 once layer 2 became a meaningful area of development. are disabled.

    • Roles:
      • admin: ProxyAdmin; ultimately Xterio Multisig
      • guardian: EOA 1
      • privilegedAddress: Safe
    The following tokens are included in the value secured calculation:
    ETH token logo

    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.

    • Roles:
      • admin: ProxyAdmin; ultimately Xterio Multisig
      • guardian: EOA 1

    Used to bridgeA message-passing protocol between two blockchains. At its most basic, a token bridge consists of a smart contract which can escrow funds on one side of the bridge, and instruct the release or minting of corresponding assets on the other side, but bridges could also support arbitrary messages. How these instructions are validated is a critical factor in assessing the trust assumptions of a bridge. ERC-721 tokens from host chain to this chain.

    • Roles:
      • admin: ProxyAdmin; ultimately Xterio Multisig

    The main entry point to deposit ERC20 tokens from host chain to this chain.

    • Roles:
      • admin: ProxyAdmin; ultimately Xterio Multisig

    All supported tokens in this escrow are included in the value secured calculation.

    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 limitThe maximum amount of gas a transaction or block may consume., it can be resubmitted via this contract’s replay function.

    • Roles:
      • admin: ProxyAdmin; ultimately Xterio Multisig

    A helper contract that generates OptimismMintableERC20 contracts on the networkA constellation of nodes (peers) that communicate via a peer-to-peer protocol, for example, in propagating transactions and blocks to other nodes. 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 OptimismMintableERC20 as this chain’s representation of a token on the host chain, or vice-versa.

    • Roles:
      • admin: ProxyAdmin; ultimately Xterio Multisig
    ProxyAdmin0x9e48…94A8
    • Roles:
      • owner: Xterio Multisig

    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).