PBFT - Is malicious leader unsafe?

Hello everyone,

I’ve been studying Canton recently and I’m wondering how the PBFT used in the GS for the sequencers is safe when a chosen leader for an ordering is malicious. Transactions may be hidden, metadata aren’t and it seems like the leader can prevail consensus in a PBFT. And I believe you choose this leader in a deterministic manner, not randomly. So… How do you handle a malicious leader case in the GS?

Thank you in advance for your answers.

Probably better to look at the CometBFT documentation for answers here, since MainNet still relies on CometBFT for the underlying ordering. All leader-related topics start there.

If you’re specifically looking at CantonBFT, that new protocol, expected to go live on MainNet later this year, is based on Narwhal and ISS; the papers on those two protocols would be a good starting point.

Canton will also publish more details about the specific implementation of Narwhal and ISS used in Canton BFT.