Taiko
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About
Taiko is an Ethereum-equivalent Optimistic Rollup on the Ethereum network. In the future it aims to add zkVerifier making it a hybrid, optimistic-zk construction. Taiko combines based sequencing and a contestation mechanism with multi-proofs.
Badges
About
Taiko is an Ethereum-equivalent Optimistic Rollup on the Ethereum network. In the future it aims to add zkVerifier making it a hybrid, optimistic-zk construction. Taiko combines based sequencing and a contestation mechanism with multi-proofs.
Taiko Based Sequencing Upgrade
2024 Jun 6th
Proposing blocks on Taiko is now permissionless.
Sequencer failure
Self sequenceState validation
SGX proofsTaiko uses a multi-tier proof system to validate the state. However, current tier proofs include either SGX (secure-enclave) execution verification, or approval by a minimum number of Guardians. State validation through the Zk-proof tier is not yet active. Each proof goes through a cooldown window allowing for contestation. Contested blocks require proof from a higher level tier. If no contestation is made, or the block has been proven by the highest tier, the proof is considered valid. The system allows for an invalid state to be proven by either a compromised SGX instance or compromised Guardians (the highest tier). This can lead to a state being proven as valid when it is not.
Exit window
NoneThere is no window for users to exit in case of an unwanted upgrade since contracts are instantly upgradable.
Taiko is a Multi-tier proof system
Taiko uses a multi-tier proof system to validate the state. Currently there are three tiers, SGX tier, 1/8 Guardian tier and 6/8 Guardian tier (from lowest to highest). When proposing a block, the sequencer is assigned the designated prover role for that block. The prover is required to deposit a liveness bond (125.0 TAIKO) as a commitment to prove the block, which will be returned once the block is proven. The SGX tier has a proving window of 1h, during which only the designated prover can submit proof for the block. Once elapsed, proving is open to everyone able to submit SGX proofs. After the proof is submitted, anyone within the cooldown window - for SGX tier is 1d - can contest the block by submitting a bond. For the SGX Proof tier, the validity bond is currently set to 125.0 TAIKO, while 820.0 TAIKO is required to contest the proof. For the Minority guardian tier, validity and contest bonds are set to 250.0 TAIKO and 1640.0 TAIKO, respectively. It is not required to provide a proof for the block to submit a contestation. When someone contests, a higher level tier has to step in to prove the contested block. Decision of the highest tier (currently the 6/8 Guardian) is considered final. If no one challenges the original SGX proof, it finalizes after 1d (the cooldown window).
Funds can be stolen if a malicious block is proven by a compromised SGX instance or approved by Guardians.
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 blobs. This ensures that it will be available for enough time.
The system uses a based sequencing mechanism
The system uses a based (or L1-sequenced) sequencing mechanism. Anyone can sequence Taiko L2 blocks by proposing them directly on the TaikoL1 contract. The proposer of a block is assigned the designated prover role, and will be the only entity allowed to provide a proof for the block during the initial proving window. Currently, proving a block requires the block proposer to run an SGX instance. Proposing a block also requires depositing a liveness bond as a commitment to proving the block. Unless the block proposer proves the block within the proving window, it will forfeit its liveness bond to the TaikoL1 smart contract.
The system uses the following set of permissioned addresses:
This is a Gnosis Safe with 3 / 4 threshold. Currently also designated as the Security Council. Can upgrade proxies without delay, remove SGX attestation certificates, pause block proposals and block proving, among other permissions.
Those are the participants of the TaikoAdmin.
Guardians can prove blocks on the highest tier. Guardians are selected by the TaikoAdmin multisig. Acts as a 6/8 multisig.
Minority guardians can prove blocks on the second highest tier. Guardians are selected by the TaikoAdmin multisig. Acts as a 1/8 multisig.
The chain watchdog role can pause proving of blocks.
The system consists of the following smart contracts on the host chain (Ethereum):
Contract managing the multi-tier proof system.
Contract managing SGX attestation certificates.
Upgrade delay: No delay
Taiko’s native token. Used for block proposal rewards, proving bonds and rewards, and contesting bonds.
Upgrade delay: No delay
This contract provides functionalities for sequencing, proving, and verifying blocks.
Upgrade delay: No delay
This contract manages the rollup addresses list, allowing to set the address for a specific chainId-name pair.
Upgrade delay: No delay
Upgrade delay: No delay
Upgrade delay: No delay
Upgrade delay: No delay
A contract that holds TAIKO token and acts as a Taiko prover for Taiko Labs. This contract will simply relay proveBlock calls to TaikoL1 so msg.sender doesn’t need to hold any TAIKO. There are several instances of this contract operated by different entities.
Upgrade delay: No delay
The SignalService contract serves as cross-chain message passing system. It defines methods for sending and verifying signals with merkle proofs.
Upgrade delay: No delay
Shared bridge for Taiko chains for bridged ETH. This contract stores the following tokens: ETH.
Upgrade delay: No delay
Shared vault for Taiko chains for bridged ERC20 tokens. This contract can store any token.
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).