Eventualities need to be binding not just to a plan, yet to the execution of
the plan (the outputs). Bitcoin's Eventuality definition short-cutted this
under a honest multisig assumption, causing the following issue:
If multisig n+1 is verifying multisig n's actions, as detailed in
multi-multisig's document on multisig rotation, it'll check no outstanding
eventualities exist. If we solely bind to the plan, a malicious multisig n
could steal outbound payments yet cause the plan to be marked as successfully
completed.
By modifying the eventuality to also include the expected outputs, this is no
longer possible. Binding to the expected input is preserved in order to remain
binding to the plan (allowing two plans with the same output-set to co-exist).
It was a piece of duplicated data used to achieve context-less
de)serialization. This new Vec code is a bit tricker to first read, yet overall
clean and removes a potential fault.
Saves 2 bytes from DkgShares messages.
See prior commit message for more info.
With the plan for the batch sign ID to be just 5 bytes (potentially 4), this
does incur a +5 bytes cost compared to the ExternalBlock system *even in the
standard case*. The simplicity remains preferred at this time.
The initial TODO was simply to use one ExternalBlock per all batches in the
block. This would require publishing ExternalBlock after the last batch,
requiring knowing the last batch. While we could add such a pipeline, it'd
require:
1) Initial preprocesses using a distinct message from BatchPreprocess
2) An additional message sent after all BatchPreprocess are sent
Unfortunately, both would require tweaks to the SubstrateSigner which aren't
worth the complexity compared to the solution here, at least, not at this time.
While this will cause, if a Tributary is signing a block whose total batch data
exceeds 25 kB, to use multiple transactions which could be optimized out by
'better' local data pipelining, that's an extreme edge case. Given the temporal
nature of each Tributary, it's also an acceptable edge.
This does no longer achieve synchrony over external blocks accordingly. While
signed batches have synchrony, as they embed their block hash, batches being
signed don't have cryptographic synchrony on their contents. This means
validators who are eclipsed may produce invalid shares, as they sign a
different batch. This will be introduced in a follow-up commit.
Updates Tributary values to allow 999ms for block processing (from 2s) and
1667ms for latency (up from 1s).
The intent is to resolve#365. I don't know if this will, but it increases the
chances of success and these values should be fine in prod since Tributary is a
post-execution chain (making block procesisng time minimal).
Does embed the dagger of N::block_time() panicking if the block time in ms
doesn't cleanly divide by 1000.
Fixes where ram_scanned is updated in processor. The prior version, while safe,
would redo massive amounts of work during periods of inactivity. It also hit an
undocumented invariant where get_eventuality_completions assumes new blocks,
yet redone work wouldn't have new blocks.
Modifies Monero's generate_blocks to return the hashes of the generated blocks.
We only expect processor messages when we have the relevant Tributary. We
queued Tributary creation, yet then kicked off processor messages. We need to
wait until the Tributary is actually created to kick off processor messages.
