Karak
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About
Karak is a general-purpose Optimium.
Badges
About
Karak is a general-purpose Optimium.
Funds can be stolen if
Funds can be lost 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.
Data availability
ExternalProof construction and state derivation fully rely on data that is posted on Celestia. Sequencer tx roots are not checked against the Blobstream bridge data roots onchain, but L2 nodes can verify data availability by running a Celestia light client.
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.
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).
Data is stored on Celestia
Transactions roots are posted onchain and the full data is posted on Celestia. Since the Blobstream bridge is not used, availability of the data is not verified against Celestia validators, meaning that the Sequencer can single-handedly publish unavailable roots.
Funds can be lost if the sequencer posts an unavailable transaction root (CRITICAL).
Funds can be lost if the data is not available on the external provider (CRITICAL).
- Introducing Blobstream: streaming modular DA to Ethereum
- Derivation: Batch submission - OP Mainnet specs
- BatchInbox - Etherscan address
- OptimismPortal.sol - Etherscan source code, depositTransaction function
CelestiaThe 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 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 3d 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).
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.
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.
The system uses the following set of permissioned addresses:
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 is an actor allowed to post new state roots of the current layer to the host chain.
- This is a Gnosis Safe with 3 / 5 threshold.
- Can act on behalf of ProxyAdmin.
- Is 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.
- Is a Guardian.
- Can upgrade the implementation of L2OutputOracle, SystemConfig, L1ERC721Bridge, OptimismPortal, OptimismMintableERC20Factory (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 KarakMultisig.
Is a Proposer.
Is a Sequencer.
The system consists of the following smart contracts on the host chain (Ethereum):
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.
Upgrade delay: No delay
- Can be used to configure AddressManager - set and change address mappings.
- Can be used to upgrade implementation of L2OutputOracle, SystemConfig, L1ERC721Bridge, OptimismPortal, OptimismMintableERC20Factory.
- Can be used to upgrade implementation of L1StandardBridge - upgrading the bridge implementation can give access to all funds escrowed therein.
Used to bridge ERC-721 tokens from host chain to this chain.
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.
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.
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.
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.
Upgrade delay: No delay
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.
Upgrade delay: No delay
Main entry point for users depositing ETH.
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).
