Metal
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About
Metal L2 is a general-purpose OP stack rollup by Metallicus focused on banking and compliance.
Badges
About
Metal L2 is a general-purpose OP stack rollup by Metallicus focused on banking and compliance.
Recategorisation
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:
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.
2024 Mar 28 — 2025 Feb 21
2024 Mar 27 — 2025 Feb 20
The section shows the operating costs that L2s pay to Ethereum.
2024 Feb 21 — 2025 Feb 20
Funds can be stolen if
Funds can be frozen if
MEV can be extracted if
Sequencer failure
Self sequenceState validation
NoneCurrently the system permits invalid state roots. More details in project overview.
Exit window
NoneThere is no window for users to exit in case of an unwanted regular upgrade since contracts are instantly upgradable.
Proposer failure
Cannot withdrawOnly the whitelisted proposers can publish state roots on L1, so in the event of failure the withdrawals are frozen.
Metal is a 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).
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.
- Derivation: Batch submission - OP Mainnet specs
- BatchInbox - address
- OptimismPortal.sol - source code, depositTransaction function
EthereumThe 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.
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.
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. The process of block finalization takes a challenge period 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).
Forced messaging
If the user experiences censorship from the operator with regular L2->L1 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.
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.
Ethereum
Roles:
Allowed to challenge or delete state roots proposed by a Proposer.
Used in:
Allowed to pause deposits and withdrawals.
- OpFoundationUpgradeSafe has the role if the number of SecurityCouncilMultisig members falls below 8
- OpFoundationOperationsSafe has the role if not revoked by the Security Council
Allowed to post new state roots of the current layer to the host chain.
Allowed to commit transactions from the current layer to the host chain.
Actors:
Is allowed to interact with LivenessModule - can remove members of SecurityCouncilMultisig inactive for 98d.
Used in:
Participants (9):
0x5093…66280xA073…bda20xF331…647D0xF0B7…A4f00xa400…e6e40x3840…Fd5f0xa0C6…90380xefCf…dD5C0x4D80…5BAeUsed in:
- A Multisig with 2 / 2 threshold.
- Can act on behalf of ProxyAdmin, SuperchainProxyAdmin.
- Is allowed to interact with AddressManager - set and change address mappings - acting via ProxyAdmin.
- Is allowed to interact with Lib_AddressManager - set and change address mappings - acting via SuperchainProxyAdmin.
- Can upgrade the implementation of OptimismMintableERC20Factory, L2OutputOracle, OptimismPortal, L1ERC721Bridge, SystemConfig - acting via ProxyAdmin.
- Can upgrade the implementation of L1StandardBridge - upgrading the bridge implementation can give access to all funds escrowed therein - acting via ProxyAdmin.
- Can upgrade the implementation of SuperchainConfig - acting via SuperchainProxyAdmin.
Used in:
- A Multisig with 5 / 7 threshold.
- Member of SuperchainProxyAdminOwner.
- Can act on behalf of LivenessModule - takes ownership of SecurityCouncilMultisig if the number of SecurityCouncilMultisig members falls below 8.
- A Guardian - acting via SuperchainGuardianMultisig, SecurityCouncilMultisig, LivenessModule if the number of SecurityCouncilMultisig members falls below 8.
Used in:
- A Multisig with 5 / 7 threshold.
- Can act on behalf of DeputyGuardianModule if not revoked by the Security Council.
- A Guardian - acting via SuperchainGuardianMultisig, DeputyGuardianModule if not revoked by the Security Council.
Used in:
- A Multisig with 10 / 13 threshold. It uses the following modules: LivenessModule (used to remove members inactive for 98d while making sure that the threshold remains above 75%. If the number of members falls below 8, the OpFoundationUpgradeSafe takes ownership of the multisig).
- Member of SuperchainGuardianMultisig, SuperchainProxyAdminOwner.
- A Guardian - acting via SuperchainGuardianMultisig.
Participants (13):
0x07dC…d0730x652B…cB5f0x1822…925e0x4A73…e61E0x51aC…3dDa0xEF9A…877c0x6323…c8650xd5b7…aC900x7ed8…9E390x0aA3…75D70x9Eb1…fD7A0xbfA0…E0d90x9282…cACbUsed in:
- A Multisig with 1 / 1 threshold. It uses the following modules: DeputyGuardianModule (allows the OpFoundationOperationsSafe, called the deputy guardian, to act on behalf of the Gnosis Safe).
- Can act as a Guardian.
Participants (1):
SecurityCouncilMultisigUsed in:
- A Multisig with 2 / 2 threshold.
- Member of OpFoundationUpgradeSafe, OpFoundationOperationsSafe.
Used in:
Ethereum
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.
Implementation used in:
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.
Implementation used in:
- Can be used to interact with AddressManager - set and change address mappings.
- Can be used to upgrade implementation of OptimismMintableERC20Factory, L2OutputOracle, OptimismPortal, L1ERC721Bridge, SystemConfig.
- Can be used to upgrade implementation of L1StandardBridge - upgrading the bridge implementation can give access to all funds escrowed therein.
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.
Implementation used in:
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.
Implementation used in:
Used to bridge ERC-721 tokens from host chain to this chain.
Implementation used in:
- Can be used to interact with Lib_AddressManager - set and change address mappings.
- Can be used to upgrade implementation of SuperchainConfig.
Implementation used in:
The main entry point to deposit ERC20 tokens from host chain to this chain. This contract can store any token.
Implementation used in:
Used to manage global configuration values for multiple OP Chains within a single Superchain network. The SuperchainConfig contract 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.
Proxy used in:
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.
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.
Implementation used in:
Value Secured is calculated based on these smart contracts and tokens:
Main entry point for users depositing ERC20 token that do not require custom gateway.
Implementation used in:
Main entry point for users depositing ETH.
Implementation used in:
The current deployment carries some associated risks:
Funds can be stolen if a contract receives a malicious code upgrade. Both regular and emergency upgrades must be approved by both the Security Council and the Foundation. There is no delay on regular upgrades.
