Alternate PBS: A PBS Proposal for Based Rollups

[CTra1n]

@jsky

However, it doesn’t resolve the ability and economic incentive for a L1 proposer to censor the L2 block, whether it is proposed by the trusted proposer or someone paying the backdoorFee.

There shouldn’t be much of an incentive for an L1 proposer to censor a block from the trusted L2 set if the value of the block is less than backdoorFee. In this case, as long as the L2 block pays a sufficient fee, the block should be included. Otherwise, the value of the L2 block is greater than the backdoorFee, in which case, censoring/stealing comes into play. Are you thinking of something more malicious from the L1 proposer? You mention economic incentive to censor, so maybe an example might help?

@jsky

if we’re introducing intermediary layers to tx submission for L2s, which seems inevitable given the need to buy fractions of blobs post 4844, we should also get fast confirmations.

Makes sense. As I mentioned in the first reply, I think backdoorFee() can be more expressive and allow for something like the preconfirmations mentioned here. Can the slots/blocks where preconfirmations are allowed also allow for MEV retention? This is a tricky question.

Things could get wacky and the right to be a preconfirmer could be auctioned in advance: “If you are the L1 proposer for block N and you pay preconfirm_backdoorFee(N,…), you can be designated as a preconfirmer for that block”.

@jsky

a high level Astria’s design looks quite similar to this in that the shared sequencer proposer set will initially be Proof of Governance and will run a PBS auction for block creation.

That’s always an option. I guess the parallel with our proposal would be “should the rollups themselves run their own value-capturing auction before entering the shared sequencer auction?”