Taiko Alethia

Taiko uses a multi-tier proof system to validate state transitions. There are five tiers: The SGX tier, two ZK tiers with RISC0 and SP1 verifiers, the 1/8 Guardian tier and the 6/8 Guardian tier (from lowest to highest). Since the Guardian tiers are the highest, validity proofs can generally be overwritten by a single Guardian. Consequently, there is no way to force the RISC0 or SP1 tiers.

When proposing a batch (containing one or multiple L2 blocks), the proposer is assigned the designated prover role for that batch and is required to deposit a liveness bond (125.0 TAIKO) as a commitment to prove the batch, which will be returned once the batch is proven. The default (lowest) SGX tier has a proving window of 5h, during which only the designated prover can submit the proof for the batch. Once elapsed, proving is open to everyone able to submit SGX proofs and a validity bond. The two ZK tiers have a proving window of 7h.

After the proof is submitted and during its 4h cooldown window, anyone can dispute the batch by submitting a contest bond. Anyone can then prove this new dispute by submitting a validity bond as a commitment to win the respective higher-tier proof. A validity bond is TAIKO 100.0 for SGX vs 150.0 for ZK tiers, while a contest bond is TAIKO 656.25 for SGX vs. 984.375 for the two ZK tiers. For the Minority guardian tier, validity and contest bonds are set to 200.0 TAIKO and 1312.5 TAIKO, respectively. The highest Guardian tier does not require bonds.

It is not required to provide a proof for the batch to submit a contestation. When someone contests, a higher level tier has to step in to prove the contested batch. Decision of the highest tier (currently the 6/8 Guardian) is considered final. If no one challenges the original SGX proof, it finalizes after 4h (the cooldown window).