How do coprocessors achieve consensus?

[yuucyf]

Hello,

An event is emitted on L1 to trigger a computation. Then, multiple coprocessors independently perform the same FHE computation. Since FHE is deterministic, all honest nodes produce the same ciphertext. If a quorum of coprocessors agrees on the result, the ciphertext is accepted.

However, after checking the latest code, I haven’t found the relevant part for this mechanism.
Does anyone know where the logic for this part is implemented, or can provide a link for me to look into it?

[benoit]

Hello, yes, multiple copro compute the same thing since it’s completely deterministic. Then, there is a consensus. It’s documented in eg Gateway | Protocol or in Coprocessor | Protocol.

Typical lines where it happens are

• fhevm/gateway-contracts/contracts/InputVerification.sol at main · zama-ai/fhevm · GitHub for input verification
• fhevm/gateway-contracts/contracts/CiphertextCommits.sol at main · zama-ai/fhevm · GitHub when a ciphertext handle (and digest) is adedd to the gateway

Cheers

[yuucyf]

That’s exactly what I needed. Thank you!​