I was looking into ex-post reorg presentations and documents by Caspar Schwarz.


I got something awkward. In ex-post reorg explanation, it seems like attesters doesn't consider attestations from the current slot for deciding current head block.

So Caspar says that when proposer boost is 0, for ex-post reorg, attackers need to have 2/3 votes in n+1 slot and n+2 slot for pulling out n+1 block.

In slot n+1, 1/3 honest attesters will vote for n+1 block, and 2/3 attackers will vote for n block.

The problem is in slot n+2. In slot n+2, Caspar says attackers need 2/3 of the committee because 1/3 honest attesters will vote for n+1 block (because n+1 block has 1/3 votes already, but n+2 block has nothing).

However, what if attackers broadcast their attestation for n+2 slot right after they broadcast the n+2 block?

Then honest attesters will include those attestations for head decision. Then it means attackers just need 1/3 of the committee for fighting with the 1/3 votes of honest attesters in n+1 slot.

Please let me know if this is wrong.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.