Subject: Re: [bitcoin-dev] On a new community process to specify covenants

From: Antoine Riard <[email-masked]>
Date: Sat, 23 Jul 2022 17:41:55 +0100

Hi Michael,

> One cautionary word from someone who is probably still feeling the
effects of burn out from the activation drama earlier in the year. No
process can guarantee community > consensus at the end of it especially if
some of those who we consider experts in this area only tentatively
participate. The personal attacks and ignoring of views counter >to those
who were pushing an activation attempt really should not be repeated.
(Especially if this process is seeking to include those who we consider
experts in this area > and don't want their participation to be perceived
as tacit approval of whatever is attempted next.)

I'm thinking such a covenant effort would be more a technical process
aiming to advance the state of covenant & contracting knowledge, collect
and document the use-cases, exchange engineering learnings from the
prototype, share the problem space, etc. In the same fashion we have the
BOLT one or even more remote the IETF working groups about a bunch of
Internet technology [0]. I think that Taproot/Schnorr has set a high
standard in terms of safety-first and careful Bitcoin engineering effort,
aggregating 8 years of thinking around MAST and friends but also exploring
other signature schemes like BLS. And I hope with covenants we aim for
higher standards, as if there is one learning from Taproot we could have
spent more time working out use-cases prototypes (e.g joinpools) and
standard libraries to mature, it could have save actual headache around
x-pubkeys [1]

In my perspective, activation is more a matter of release engineering and
community communications, and failing to a game-theory situation where
miners incentives are computed is more a hint of a social layer failure.
When we start to consider the moves and incentives of categories of Bitcoin
players (miners, users, exchanges, ...), I would say we failed to keep the
community as one and increase the safety risks for everyone's coins.

Minding that, and to maximize the participation in such a covenant
specification process, similar to the usual Chatham House rules in
engineering meetings, I believe it could be good to have a "No Activation -
No Timeframe" rule in such a covenant process, and defer any activation
discussion to a future process of its own.

> As long as this is understood and agreed by participants I can only see
positives coming out of this. But please let's not repeat the activation
drama from earlier in the year > because a process with a subset of those
who we would consider experts in this area come to a view and then try to
ram that view down everyone's throats by attempting > activation at the end
of it. Maybe this will result in community consensus on covenant
proposal(s) going forward but also maybe it won't. Either outcome is fine.
At the very > least research will progress and work will be carried out
that moves us in a positive direction

During the last LN Summit in Oakland, there was chit-chat on how long it
would take to get a mature version of Lightning, and the answer from a
seasoned FOSS developer was 25 years. Considering the heavy LN
problem-space, I think this was a wise take and I believe with covenants we
would have to think in that 10/20 years perspective if we aim for a
satisfying and complete covenant toolchain. It doesn't mean we are not
going to be able to deploy piece by piece, however there is a strong
emphasis to be done on the archiving part itself. Some of the process
stakeholders might still not be active in their engineering careers when
the issues should be weighted for consensus activation and transmission of
knowledge across generations of stakeholders is going to be an issue (as we
already see it in Bitcoin Core with some critical subsystems). And if there
is never community consensus on covenant proposals, that's fine. To me the
research would have been interesting in itself and I hope it will be the
same for other participants.

[0] https://datatracker.ietf.org/wg/
[1]
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2022-July/020663.html

Le sam. 23 juil. 2022 à 15:25, Michael Folkson <
[email-masked]> a écrit :

> Hi Antoine
>
> This looks great and I can certainly see progress being made in a number
> of directions on this. I thought you did a great job with the L2 onchain
> support workshops and I'm sure you'll do a great job moving this forward.
>
> One cautionary word from someone who is probably still feeling the effects
> of burn out from the activation drama earlier in the year. No process can
> guarantee community consensus at the end of it especially if some of those
> who we consider experts in this area only tentatively participate. The
> personal attacks and ignoring of views counter to those who were pushing an
> activation attempt really should not be repeated. (Especially if this
> process is seeking to include those who we consider experts in this area
> and don't want their participation to be perceived as tacit approval of
> whatever is attempted next.)
>
> As long as this is understood and agreed by participants I can only see
> positives coming out of this. But please let's not repeat the activation
> drama from earlier in the year because a process with a subset of those who
> we would consider experts in this area come to a view and then try to ram
> that view down everyone's throats by attempting activation at the end of
> it. Maybe this will result in community consensus on covenant proposal(s)
> going forward but also maybe it won't. Either outcome is fine. At the very
> least research will progress and work will be carried out that moves us in
> a positive direction.
>
> Thanks
> Michael
>
> --
> Michael Folkson
> Email: michaelfolkson at protonmail.com
> Keybase: michaelfolkson
> PGP: 43ED C999 9F85 1D40 EAF4 9835 92D6 0159 214C FEE3
>
> ------- Original Message -------
> On Wednesday, July 20th, 2022 at 21:42, Antoine Riard via bitcoin-dev <
> [email-masked]> wrote:
>
> Hi,
>
> Discussions on covenants have been prolific and intense on this mailing
> list and within the wider Bitcoin technical circles, I believe however
> without succeeding to reach consensus on any new set of contracting
> primitives satisfying the requirements of known covenant-enabled use-cases.
> I think that's a fact to deplore as covenants would not only offer vast
> extensions of the capabilities of Bitcoin as a system, i.e enabling new
> types of multi-party contract protocols. But also empowering Bitcoin on its
> fundamental value propositions of store of value (e.g by making vaults more
> flexible) and payment system (e.g by making realistic channel
> factories/payment pools).
>
> If we retain as a covenant definition, a spending constraint restricting
> the transaction to which the spent UTXO can be spent, and enabling to
> program contracts/protocols at the transaction-level instead of the
> script-level, the list of Script primitives proposed during the last years
> has grown large : ANYPREVOUT [0], CHECKSIGFROMSTACK [1],
> CHECK_TEMPLATE_VERIFY [2], TAPROOT_LEAF_UPDATE_VERIFY [3], TXHASH [4],
> PUSHTXDATA [5], CAT [6], EVICT [7], Grafroot delegation [8], SIGHASH_GROUP
> [9], MERKLEBRANCHVERIFY [10] and more than I can't remember. Of course, all
> the listed primitives are at different states of formalization, some
> already fully fleshed-out in BIPs, other still ideas on whiteboard, yet
> they all extend the range of workable multi-party contract protocols.
>
> Indeed this range has grown wild. Without aiming to be exhaustive (I'm
> certainly missing some interesting proposals lost in the abyss of
> bitcointalk.org), we can mention the following use-cases: multi-party
> stateful contracts [11], congestion trees [12], payment pools [13], "eltoo"
> layered commitments [14], programmable vaults [15], multi-events contracts
> [16], blockchain-as-oracle bets [17], spacechains [18], trustless
> collateral lending [19], ...
>
> Minding all those facts, I would say the task of technical evaluation of
> any covenant proposal sounds at least two fold. There is first reasoning
> about the enabled protocols on a range of criterias such as scalability,
> efficiency, simplicity, extensibility, robustness, data confidentiality,
> etc. Asking questions like what are the interactions between layers, if any
> ? Or how robust is the protocol, not just interactivity failure between
> participant nodes but in the face of mempools spikes or internet disruption
> ? Or if the performance is still acceptable on shared resources like
> blockspace or routing tables if everyone is using this protocol ? Or if the
> protocol minimizes regulatory attack surface or centralization vectors ?
>
> Though once this step is achieved, there is still more reasoning work to
> evaluate how good a fit is a proposed Script primitive, the
> efficiency/simplicity/ease to use trade-offs, but also if there are no
> functionality overlap or hard constraints on the use-cases design
> themselves or evolvability w.rt future Script extensions or generalization
> of the opcode operations.
>
> Moreover, if you would like your evaluation of a covenant proposal to be
> complete, I don't believe you can squeeze the implications with the mempool
> rules and combination with any consistent fee-bumping strategy. To say
> things politely, those areas have been a quagmire of vulnerabilities,
> attacks and defects for second-layers Bitcoin protocols during the last
> years [20].
>
> Considering the abundant problem-space offered by covenants, I believe
> there is a reasonable groundwork to pursue in building the use-cases
> understanding (e.g prototype, pseudo-specification, documentation, ...) and
> building consensus on the framework of criterias on which to evaluate them
> [21]. It might raise a really high bar for any covenant proposal compared
> to previous softforks, however I think it would adequately reflect the
> growth in Bitcoin complexity and funds at stakes during the last years.
>
> Moving towards this outcome, I would like to propose a new covenant open
> specification process, in the same spirit as we have with the BOLTs or
> dlcspecs. We would have regular meetings (biweekly/monthly ?), an open
> agenda where topics of discussion can be pinned in advance and
> documentation artifacts would be built with time driven by consensus (e.g
> 1st phase could be to collect, pseudo-specify and find champion(s) for
> known use-cases ?) and no timeframe. Starting date could be September /
> October / November (later, 2023 ?), giving time for anyone interested in
> such a covenant process to allocate development and contribution bandwidth
> in function of their involvement interest.
>
> Learning from the good but specially from the bad with setting up the L2
> onchain support meetings last year, I think it would be better to keep the
> agenda open, loose and free as much we can in a "burn-the-roadmap" spirit,
> avoiding to create a sense of commitment or perceived signaling in the
> process participants towards any covenant solution. I would guess things to
> be experimental and evolutionary and folks to spend the first meetings
> actually to express what they would like the covenant process to be about
> (and yes that means if you're a domain expert and you find the pace of
> things too slow sometimes, you have to learn to handle your own
> frustration...).
>
> In a "decentralize-everything" fashion, I believe it would be good to have
> rotating meeting chairs and multiple covenant documentation archivists. I'm
> super happy to spend the time and energy bootstrapping well such covenant
> process effort, though as it's Bitcoin learn to decentralize yourself.
>
> I'm really curious what the outcome of such a covenant process would look
> like. We might end up concluding that complex covenants are too unsafe by
> enabling sophisticated MEV-attacks against LN [22]. Or even if there is an
> emergent technical consensus, it doesn't mean there is a real market
> interest for such covenant solutions. That said, I'm not sure if it's
> really a subject of concern when you're reasoning as a scientist/engineer
> and you value technical statements in terms of accuracy, systematic
> relevance and intrinsic interest.
>
> Overall, my motivation to kick-start such a process stays in the fact that
> covenants are required building blocks to enable scalable payments pools
> design like CoinPool. I believe payments pools are a) cool and b) a good
> shot at scaling Bitcoin as a payment system once we have reached
> scalability limits of Lightning, still under the same security model for
> users. However, as a community we might sense it's not the good timing for
> a covenant process. I'm really fine with that outcome as there are still
> holes to patch in LN to keep me busy enough for the coming years.
>
> Zooming out, I believe with any discussion about covenants or other soft
> forks, the hard part isn't about coming up with the best technical solution
> to a set of problems but in the iterative process where all voices are
> listened to reach (or not) consensus on what is actually meant by "best"
> and if the problems are accurate. The real physics of Bitcoin is the
> physics of people. It's a work of patience.
>
> Anyways, eager to collect feedbacks on what the ideal covenant
> specification process looks like. As usual, all opinions and mistakes are
> my own.
>
> Cheers,
> Antoine
>
> [0] https://github.com/bitcoin/bips/blob/master/bip-0118.mediawiki
> [1] https://bitcoinops.org/en/topics/op_checksigfromstack/
> [2] https://github.com/bitcoin/bips/blob/master/bip-0119.mediawiki
> [3]
> https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-September/019419.html
> [4]
> https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2022-January/019813.html
> [5] https://github.com/jl2012/bips/blob/vault/bip-0ZZZ.mediawiki
> [6] https://medium.com/blockstream/cat-and-schnorr-tricks-i-faf1b59bd298
> [7]
> https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2022-February/019926.html
> [8]
> https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-February/015700.html
> [9]
> https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-July/019243.html
> [10] https://github.com/bitcoin/bips/blob/master/bip-0116.mediawiki
> [11]
> https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2022-January/019808.html
> [12]
> https://github.com/bitcoin/bips/blob/master/bip-0119.mediawiki#Congestion_Controlled_Transactions
> [13]
> https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2020-June/017964.html
> [14]
> https://lists.linuxfoundation.org/pipermail/lightning-dev/2020-January/002448.html
> [15] http://fc17.ifca.ai/bitcoin/papers/bitcoin17-final28.pdf
> [16]
> https://github.com/ariard/talk-slides/blob/master/advanced-contracts.pdf
> [17] https://blog.bitmex.com/taproot-you-betcha/
> [18]
> https://gist.github.com/RubenSomsen/c9f0a92493e06b0e29acced61ca9f49a#spacechains
> [19] https://gist.github.com/RubenSomsen/bf08664b3d174551ab7361ffb835fcef
> [20] https://github.com/jamesob/mempool.work
> [21] https://github.com/bitcoinops/bitcoinops.github.io/pull/806
> [22] https://blog.bitmex.com/txwithhold-smart-contracts/
>
>
>