Return-Path: Received: from smtp2.osuosl.org (smtp2.osuosl.org [IPv6:2605:bc80:3010::133]) by lists.linuxfoundation.org (Postfix) with ESMTP id A9F74C002C for ; Thu, 21 Apr 2022 06:25:21 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id A5980402B1 for ; Thu, 21 Apr 2022 06:25:21 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org X-Spam-Flag: NO X-Spam-Score: -2.098 X-Spam-Level: X-Spam-Status: No, score=-2.098 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no Authentication-Results: smtp2.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Uufvr-BwqmPk for ; Thu, 21 Apr 2022 06:25:19 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.8.0 Received: from mail-lj1-x22a.google.com (mail-lj1-x22a.google.com [IPv6:2a00:1450:4864:20::22a]) by smtp2.osuosl.org (Postfix) with ESMTPS id 5787840241 for ; Thu, 21 Apr 2022 06:25:19 +0000 (UTC) Received: by mail-lj1-x22a.google.com with SMTP id q14so4504313ljc.12 for ; Wed, 20 Apr 2022 23:25:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Dud4KMy7tm5f8P6sqBrS7qsWJ/MgFZblZypoH8vBYa8=; b=AXq86tO9pCNb9R5qfbCAHa9Vf2vN8MfwOC2jZJu4PRThVeV5A0C+sXWzw45hit8p+T Cc9Ma5orEmVfjwYkqY+jDUxCpuZWkR+TpZoh88D0jYivpGIPJDoosMXEhRLFr6N5xDGJ BXHJP0QzoEzTn/rfK/eBTKsW+k3CJeASmyOiXmtFcUcLB9Nsm+pzbDDc2UPZ63458y8m ul5x8V3PwfgAEUiRQfNOkRX86squqMKMyMxQJqlARYIIjuiwxoMVkG/9AepZyE4iSqrE rEEDMLxStNh6DcYNcnbDW6T5KXjSq1DLihAHTbbAj4T114b+IgqTVCDER7FfrNmLmisi 3vYA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Dud4KMy7tm5f8P6sqBrS7qsWJ/MgFZblZypoH8vBYa8=; b=f4ToeEZJgmmSwuu/8lX/b6wiXBh4aRrAZw54gku2xDvG2MHlcxl9ftob06TSTSt8yH 3sJpFSafIizATTC7NuG9ruACzXzU7JPSSTAYbNoaQEt4VTyXlMBR05mXuAZc8Me9+bS0 YCPBEPGf12z/pKNqiqX50e3Toh9TELeit1pbVqJcFzTpffllNOtvKbYRBw/qfCcALQ+F aNCjp6IQeYPAHv5lWaLq+T/EiYo6lis5fy1RHN5wmvAzcq+l4qIczD6oicu3CmRHnKvJ ooqw0FyFviGchQgcpMCpGwVDfurvXfc1bACE0nT8+GhUY+Vv1zxpwKAm5nNny8KfkLfb 6gJw== X-Gm-Message-State: AOAM5324BuXIatssQl2kwb4XkJCmZZxjxoHle8w2LTGmlFftPU3KNTFo s01WQYxum7VsUyJe5IumEl56TYTxY+vXYNhViG+jeivwiJc= X-Google-Smtp-Source: ABdhPJxD+PWkKFEYd1B9Qge56Cqryjv/prlZIVT/aiHQoNni58Fsa2d01NqxeUCLtHEkEuDN1kmm6JP4vrdq7KTCbeE= X-Received: by 2002:a05:651c:12c1:b0:249:7e8c:d5fc with SMTP id 1-20020a05651c12c100b002497e8cd5fcmr15197686lje.33.1650522316652; Wed, 20 Apr 2022 23:25:16 -0700 (PDT) MIME-Version: 1.0 References: <20220421050351.GA5616@erisian.com.au> In-Reply-To: From: Jeremy Rubin Date: Thu, 21 Apr 2022 01:25:05 -0500 Message-ID: To: Anthony Towns , Bitcoin Protocol Discussion Content-Type: multipart/alternative; boundary="00000000000060c1ab05dd242cd8" Subject: Re: [bitcoin-dev] CTV Signet Parameters X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 21 Apr 2022 06:25:21 -0000 --00000000000060c1ab05dd242cd8 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Missed one for part 2: Shesek's social recovery wallet using CTV to enforce timelocks without expiry, using his Minsc toolchain: https://twitter.com/shesek/status/1511619296367153153 https://docs.google.com/presentation/d/1B59CdMIXW-wSW6CaLSgo7y4kvgrEwVgfY14= IW2XV_MA/edit#slide=3Did.g1235f9ffb79_0_81 https://github.com/shesek/plebfi2022-social-recovery -- @JeremyRubin On Thu, Apr 21, 2022 at 1:16 AM Jeremy Rubin wrote: > Probably merits a more thorough response, but, I wanted to respond on the > framework above: > > > 1a) can you make transactions using the new feature with bitcoin-cli, > eg createrawtransaction etc? (*YES)* > > since ~Feb 2020, this has existed: > https://github.com/JeremyRubin/bitcoin/tree/checktemplateverify-feb1-work= shop > > CTV hasn't changed so this code should work un-rebased. The transaction > outputs may need to be manually submitted to the network, but the covenan= t > is enforced. This covers congestion control and vaults. > > > 1b) can you make transactions using the new feature with some other > library? *(YES)* > Sapio, Test Framework, also https://min.sc/nextc/ produced independently > by Shesek > > 1c) can you make transactions using the new feature with most common > libraries? *(YES, kinda)* > > Yes, https://crates.io/crates/sapio-miniscript and > https://crates.io/crates/sapio-bitcoin have been maintained for about 1 > year, and are now taproot compatible. > > Sapio's use of these libraries has even helped find bugs in the release > process of Taproot for rust-bitcoin. > > kinda: It's not _most_ common libraries, it's _a_ common library. it's > also not upstreamed, because the patches would not be accepted were it to > be. > > 2) has anyone done a usable prototype of the major use cases of the new > feature?* (YES)* > > In addition to https://github.com/jamesob/simple-ctv-vault, there is also > https://github.com/kanzure/python-vaults, although it has an interesting > bug. > > There's also a myriad of uses shown in > https://github.com/sapio-lang/sapio/tree/master/sapio-contrib/src/contrac= ts > and in https://github.com/sapio-lang/sapio/tree/master/plugin-example. > While these aren't quite "usable" as an end-to-end application, e.g., > something you'd want to put real money on, they are a part of a *massive* > infrastructure investment in general purpose smart contract tooling for > covenant design with CTV. That CTV can be targeted with a compiler to > generate a wide variety of composable use cases *is* one of the use cases > for CTV, since it enables people to design many different types of thing > relatively easily. That is a feature of CTV! It's not just for one use ca= se. > > The suite of Sapio apps are less "production ready" than they could be fo= r > a few reasons: > > 1) I've been working hard at pushing the limits of what is possible & the > theory of it v.s. making it production ready > 2) I prioritized supporting Taproot v.s. legacy script, and much of the > taproot tooling isn't production ready > 3) Sapio is really ambitious undertaking, and it will take time to make i= t > production > > That said, https://rubin.io/bitcoin/2022/03/22/sapio-studio-btc-dev-mtg-6= / > tutorial was completed by people who weren't me, and at the > pleb.fi/miami2022 one of the projects was able to use sapio congestion > control transactions as well, so it does "work". As it matures, we'll get= a > number of implemented use cases people have been excited about like DLCs, > which are implemented here > https://github.com/sapio-lang/sapio/blob/master/sapio-contrib/src/contrac= ts/derivatives/dlc.rs. > You can see the test case shows how to construct one. > > Why did I not focus on production grade? Well, production grade can alway= s > happen later, and I don't think it takes as much imagination. But the mai= n > critique I'd heard of CTV was that no one could see it being used for > anything but one or two use cases. So I built Sapio, in part, to show how > CTV could be used for an incredibly wide and diverse set of applications, > as opposed to the polish on them. > > If I knew the bar to surpass was to be polish, I probably could have take= n > a less ambitious approach with Sapio and shown like 1-2 applications > working end-to-end. But because the main feedback I got was that CTV wasn= 't > powerful enough, I opted to build a very general framework for covenants > and demonstrate how CTV fits that. > > > > > > -- > @JeremyRubin > > On Thu, Apr 21, 2022 at 12:05 AM Anthony Towns via bitcoin-dev < > bitcoin-dev@lists.linuxfoundation.org> wrote: > >> On Wed, Apr 20, 2022 at 05:13:19PM +0000, Buck O Perley via bitcoin-dev >> wrote: >> > All merits (or lack thereof depending on your view) of CTV aside, I >> find this topic around decision making both interesting and important. >> While I think I sympathize with the high level concern about making sure >> there are use cases, interest, and sufficient testing of a particular >> proposal before soft forking it into consensus code, it does feel like t= he >> attempt to attribute hard numbers in this way is somewhat arbitrary. >> >> Sure. I included the numbers for falsifiability mostly -- so people >> could easily check if my analysis was way off the mark. >> >> > For example, I think it could be reasonable to paint the list of >> examples you provided where CTV has been used on signet in a positive >> light. 317 CTV spends =E2=80=9Cout in the wild=E2=80=9D before there=E2= =80=99s a known activation >> date is quite a lot >> >> Not really? Once you can make one transaction, it's trivial to make >> hundreds. It's more interesting to see if there's multiple wallets or >> similar that support it; or if one wallet has a particularly compelling >> use case. >> >> > (more than taproot had afaik). >> >> Yes; as I've said a few times now, I think we should have had more >> real life demos before locking taproot's activation in. I think that >> would have helped avoid bugs like Neutrino's [0] and made it easier for >> hardware wallets etc to have support for taproot as soon as it was activ= e, >> without having to rush around adding library support at the last minute. >> >> [0] >> https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-November/01= 9589.html >> >> Lightning's "two independent implementations" rule might be worth aspiri= ng >> too, eg. >> >> > If we don=E2=80=99t think it is enough, then what number of unique spe= nds and >> use cases should we expect to see of a new proposal before it=E2=80=99s = been >> sufficiently tested? >> >> I don't really think that's the metric. I'd go for something more like: >> >> 1a) can you make transactions using the new feature with bitcoin-cli, >> eg createrawtransaction etc? >> 1b) can you make transactions using the new feature with some other >> library? >> 1c) can you make transactions using the new feature with most common >> libraries? >> >> 2) has anyone done a usable prototype of the major use cases of the new >> feature? >> >> I think the answers for CTV are: >> >> 1a) no >> 1b) yes, core's python test suite, sapio >> 1c) no >> 2) no >> >> Though presumably jamesob's simple ctv vault is close to being an answer >> for (2)? >> >> For taproot, we had, >> >> 1a) yes, with difficulty [1] >> 1b) yes, core's python test suite; kalle's btcdeb sometimes worked too >> 1c) no >> 2) optech's python notebook [2] from it's taproot workshops had demos f= or >> musig and degrading multisig via multiple merkle paths, though I >> think they were out of date with the taproot spec for a while >> >> [1] >> https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-October/019= 543.html >> [2] https://github.com/bitcoinops/taproot-workshop/ >> >> To some extent those things are really proxies for: >> >> 3) how well do people actually understand the feature? >> >> 4) are we sure the tradeoffs being made in this implementation of the >> feature, vs other implementations or other features actually make >> sense? >> >> 5) how useful is the feature? >> >> I think we were pretty confident in the answers for those questions >> for taproot. At least personally, I'm still not super confident in >> the answers for CTV. In particular: >> >> - is there really any benefit to doing it as a NOP vs a taproot-only >> opcode like TXHASH? Theoretically, sure, that saves some bytes; but a= s >> was pointed out on #bitcoin-wizards the other day, you can't express >> those outputs as an address, which makes them not very interoperable, >> and if they're not interoperable between, say, an exchange and its >> users trying to do a withdraw, how useful is that really ever going >> to be? >> >> - the scriptSig commitments seems very kludgy; combining multiple >> inputs likewise seems kludgy >> >> The continual push to rush activation of it certainly doesn't increase m= y >> confidence either. Personally, I suspect it's counterproductive; better >> to spend the time answering questions and improving the proposal, rather >> than spending time going around in circles about activating something >> people aren't (essentially) unanimously confident about. >> >> > In absence of the above, the risk of a constantly moving bar >> >> I'd argue the bar *should* be constantly moving, in the sense that we >> should keep raising it. >> >> > To use your meme, miners know precisely what they=E2=80=99re mining fo= r and >> what a metric of success looks like which makes the risk/costs of >> attempting the PoW worth it >> >> The difference between mining and R&D is variance: if you're competing f= or >> 50k blocks a year, you can get your actual returns to closely match your >> expected return, especially if you pool with others so your probability >> of success isn't miniscule -- for consensus dev, you can reasonably only >> work on a couple of projects a year, so your median return is likely $0, >> rather than a close match to your average/expected return. >> >> > We also have new ideas that only started coming up after Taproot >> activation (TLUV and Taro for example), so there=E2=80=99s also the unkn= own of what >> we could have once it becomes clear that it=E2=80=99s worth devoting men= tal energy >> and financial resources towards research. >> >> TLUV was an offshoot of SCRIPTREPLACE which was public (though not >> really published) since 2019. >> >> > One last wrinkle with regards to using countable metrics to determine = a >> feature=E2=80=99s =E2=80=9Cworth=E2=80=9D is that not all features are t= he same. Many of the use >> cases that people are excited to use CTV for ([5], [6]) are very long te= rm >> in nature and targeted for long term store of value in contrast to mediu= m >> of exchange. >> >> I mean, if those use cases are so exciting, it really doesn't seem much >> to ask to see them demoed live on the CTV signet that already exists? >> >> > You can build a CTV vault in signet, but you=E2=80=99ll only really se= e a lot >> of people using it when it=E2=80=99s to store real value on a time scale= measured >> in decades not minutes or days >> >> On the other hand, if the value is really "very long term" and there's n= o >> rush to implement these features and demo them ASAP, then it doesn't see= m >> like there should be a rush to adapt consensus to these use cases either= . >> Why not wait until someone does have time to finish sketching out the >> use case so they can demo them in public? >> >> > To put another way and leave CTV out of it completely, what should an >> outside, unbiased observer that doesn=E2=80=99t spend much time on Twitt= er expect >> to be able to see to evaluate the readiness or acceptability of ANYPREVO= UT, >> TLUV, >> >> For ANYPREVOUT, I would like to see a toy implementation of eltoo using >> it, that can handle fees and layered transactions (or has a good argumen= t >> why layered transactions aren't necessary). It's going to take a while >> even to update LN to taproot and PTLCs though, so eltoo doesn't seem lik= e >> it's on the immediate horizon. Besides eltoo, I don't think ANYPREVOUT >> is an optimal design for covenants, so if that was the motivation and >> not eltoo, maybe some other approach would be better. >> >> TLUV's design parameters don't really seem optimal (the mess with x-only >> pubkeys, alternatives like OP_EVICT), so I think it's still on the >> whiteboard. >> >> Cheers, >> aj >> >> _______________________________________________ >> bitcoin-dev mailing list >> bitcoin-dev@lists.linuxfoundation.org >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >> > --00000000000060c1ab05dd242cd8 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Missed one for part 2:

Shesek's social recovery=C2=A0wallet using CTV to enforce timelocks= without expiry, using his Minsc toolchain:

https://twitter.com/shesek/status/= 1511619296367153153
https://docs.google.com/pre= sentation/d/1B59CdMIXW-wSW6CaLSgo7y4kvgrEwVgfY14IW2XV_MA/edit#slide=3Did.g1= 235f9ffb79_0_81
https://github.com/shes= ek/plebfi2022-social-recovery
--
<= a href=3D"https://twitter.com/JeremyRubin" target=3D"_blank">@JeremyRubin


On Thu, Apr 21, 2022 at 1:16 AM Jeremy Rubin = <jeremy.l.rubin@gmail.com> wrote:
Probably merits a more thorough response, but, I wanted to= respond on the framework above:
<= br>

=C2=A01a) can you make transactions using the new feature w= ith bitcoin-cli,
=C2=A0 =C2=A0 =C2=A0eg createrawtransaction etc? (Y= ES)


CTV hasn't changed so this code = should work un-rebased. The transaction outputs may need to be manually sub= mitted to the network, but the covenant is enforced. This covers congestion= control and vaults.


=C2=A01b) can you make transactions using the new feature with some oth= er
=C2=A0 =C2=A0 =C2=A0library? (YES)
Sapio, Test Framework, also=C2=A0https://min.sc/nextc/ produced independ= ently by Shesek

=C2=A01c) can you make transactions using the n= ew feature with most common
=C2=A0 =C2=A0 =C2=A0libraries? (YES, kin= da)

Yes,=C2=A0https://crates= .io/crates/sapio-miniscript and=C2=A0https://crates.io/crates/sapio-bitcoin have been maintained for about 1 year, and are now taproot compatible.

Sapio's use of these l= ibraries=C2=A0has even helped find bugs in the release process of Taproot f= or rust-bitcoin.

kinda: I= t's not _most_ common libraries, it's _a_ common library. it's = also not upstreamed, because the patches would not be accepted were it to b= e.

=C2=A02) has anyone do= ne a usable prototype of the major use cases of the new
=C2=A0 =C2=A0 f= eature? (YES)

In addition to=C2=A0https://github.com/jamesob/simple-c= tv-vault, there is also=C2=A0https://github.com/kanzure/python-vaults, = although it has an interesting bug.

There's also a myriad of uses shown in=C2=A0https://github.com/sapio-lang/sapio/tree/master/sapio-contri= b/src/contracts and in=C2=A0https://github.com/sapio-= lang/sapio/tree/master/plugin-example. While these aren't quite &qu= ot;usable" as an end-to-end application, e.g., something you'd wan= t to put real money on, they are a part of a *massive* infrastructure inves= tment in general purpose smart contract tooling for covenant design with CT= V. That CTV can be targeted with a compiler to generate a wide variety of c= omposable use cases *is* one of the use cases for CTV, since it enables peo= ple to design many different types of thing relatively easily. That is a fe= ature of CTV! It's not just for one use case.

The suite of Sapio apps are less "production = ready" than they could be for a few reasons:

1) I've been working hard at pushing the limit= s of what is possible & the theory of it v.s. making it production read= y
2) I prioriti= zed supporting Taproot v.s. legacy script, and much of the taproot tooling = isn't production ready
3) Sapio is really ambitious undertaking, and it will take time= to make it production

Th= at said,=C2=A0https://rubin.io/bitcoin/2022/03/22/sapio-= studio-btc-dev-mtg-6/ tutorial was completed by people who weren't = me, and at the pleb.= fi/miami2022 one of the projects was able to use sapio congestion contr= ol transactions as well, so it does "work". As it matures, we'= ;ll get a number of implemented use cases people have been excited about li= ke DLCs, which are implemented here https://github.com/sapio-lang/sapio/blob/master/sapio-contrib/s= rc/contracts/derivatives/dlc.rs. You can see the test case shows how to= construct one.

Why did I= not focus on production grade? Well, production grade can always happen la= ter,=C2=A0and I don't think it takes=C2=A0as much imagination. But the = main critique I'd heard of CTV was that no one could see it being used = for anything but one or two use cases. So I built Sapio, in part, to show h= ow CTV could be used for an incredibly wide and diverse set of applications= , as opposed to the polish on them.

If I knew the bar to surpass was to be polish, I probably could = have taken a less ambitious approach with Sapio and shown like 1-2 applicat= ions working end-to-end. But because the main feedback I got was that CTV w= asn't powerful enough, I opted to build a very general framework for co= venants and demonstrate how CTV fits that.






On Thu, Apr 21, 2022 at 12:05 AM Anthony Towns via bitcoin-dev <= ;bitcoin-dev@lists.linuxfoundation.org> wrote:
On Wed, Apr 20, 2022 at 05:13:19PM +0000, Buck O Perley via bitcoin-de= v wrote:
> All merits (or lack thereof depending on your view) of CTV aside, I fi= nd this topic around decision making both interesting and important. While = I think I sympathize with the high level concern about making sure there ar= e use cases, interest, and sufficient testing of a particular proposal befo= re soft forking it into consensus code, it does feel like the attempt to at= tribute hard numbers in this way is somewhat arbitrary.

Sure. I included the numbers for falsifiability mostly -- so people
could easily check if my analysis was way off the mark.

> For example, I think it could be reasonable to paint the list of examp= les you provided where CTV has been used on signet in a positive light. 317= CTV spends =E2=80=9Cout in the wild=E2=80=9D before there=E2=80=99s a know= n activation date is quite a lot

Not really? Once you can make one transaction, it's trivial to make
hundreds. It's more interesting to see if there's multiple wallets = or
similar that support it; or if one wallet has a particularly compelling
use case.

> (more than taproot had afaik).

Yes; as I've said a few times now, I think we should have had more
real life demos before locking taproot's activation in. I think that would have helped avoid bugs like Neutrino's [0] and made it easier for=
hardware wallets etc to have support for taproot as soon as it was active,<= br> without having to rush around adding library support at the last minute.
[0] https://lists.l= inuxfoundation.org/pipermail/bitcoin-dev/2021-November/019589.html

Lightning's "two independent implementations" rule might be w= orth aspiring
too, eg.

> If we don=E2=80=99t think it is enough, then what number of unique spe= nds and use cases should we expect to see of a new proposal before it=E2=80= =99s been sufficiently tested?

I don't really think that's the metric. I'd go for something mo= re like:

=C2=A01a) can you make transactions using the new feature with bitcoin-cli,=
=C2=A0 =C2=A0 =C2=A0eg createrawtransaction etc?
=C2=A01b) can you make transactions using the new feature with some other =C2=A0 =C2=A0 =C2=A0library?
=C2=A01c) can you make transactions using the new feature with most common<= br> =C2=A0 =C2=A0 =C2=A0libraries?

=C2=A02) has anyone done a usable prototype of the major use cases of the n= ew
=C2=A0 =C2=A0 feature?

I think the answers for CTV are:

=C2=A01a) no
=C2=A01b) yes, core's python test suite, sapio
=C2=A01c) no
=C2=A02) no

Though presumably jamesob's simple ctv vault is close to being an answe= r
for (2)?

For taproot, we had,

=C2=A01a) yes, with difficulty [1]
=C2=A01b) yes, core's python test suite; kalle's btcdeb sometimes w= orked too
=C2=A01c) no
=C2=A02) optech's python notebook [2] from it's taproot workshops h= ad demos for
=C2=A0 =C2=A0 musig and degrading multisig via multiple merkle paths, thoug= h I
=C2=A0 =C2=A0 think they were out of date with the taproot spec for a while=

[1] https://lists.li= nuxfoundation.org/pipermail/bitcoin-dev/2021-October/019543.html
[2] https://github.com/bitcoinops/taproot-workshop/

To some extent those things are really proxies for:

=C2=A03) how well do people actually understand the feature?

=C2=A04) are we sure the tradeoffs being made in this implementation of the=
=C2=A0 =C2=A0 feature, vs other implementations or other features actually = make
=C2=A0 =C2=A0 sense?

=C2=A05) how useful is the feature?

I think we were pretty confident in the answers for those questions
for taproot. At least personally, I'm still not super confident in
the answers for CTV. In particular:

=C2=A0- is there really any benefit to doing it as a NOP vs a taproot-only<= br> =C2=A0 =C2=A0opcode like TXHASH? Theoretically, sure, that saves some bytes= ; but as
=C2=A0 =C2=A0was pointed out on #bitcoin-wizards the other day, you can'= ;t express
=C2=A0 =C2=A0those outputs as an address, which makes them not very interop= erable,
=C2=A0 =C2=A0and if they're not interoperable between, say, an exchange= and its
=C2=A0 =C2=A0users trying to do a withdraw, how useful is that really ever = going
=C2=A0 =C2=A0to be?

=C2=A0- the scriptSig commitments seems very kludgy; combining multiple
=C2=A0 =C2=A0inputs likewise seems kludgy

The continual push to rush activation of it certainly doesn't increase = my
confidence either. Personally, I suspect it's counterproductive; better=
to spend the time answering questions and improving the proposal, rather than spending time going around in circles about activating something
people aren't (essentially) unanimously confident about.

> In absence of the above, the risk of a constantly moving bar

I'd argue the bar *should* be constantly moving, in the sense that we should keep raising it.

> To use your meme, miners know precisely what they=E2=80=99re mining fo= r and what a metric of success looks like which makes the risk/costs of att= empting the PoW worth it

The difference between mining and R&D is variance: if you're compet= ing for
50k blocks a year, you can get your actual returns to closely match your expected return, especially if you pool with others so your probability
of success isn't miniscule -- for consensus dev, you can reasonably onl= y
work on a couple of projects a year, so your median return is likely $0, rather than a close match to your average/expected return.

> We also have new ideas that only started coming up after Taproot activ= ation (TLUV and Taro for example), so there=E2=80=99s also the unknown of w= hat we could have once it becomes clear that it=E2=80=99s worth devoting me= ntal energy and financial resources towards research.

TLUV was an offshoot of SCRIPTREPLACE which was public (though not
really published) since 2019.

> One last wrinkle with regards to using countable metrics to determine = a feature=E2=80=99s =E2=80=9Cworth=E2=80=9D is that not all features are th= e same. Many of the use cases that people are excited to use CTV for ([5], = [6]) are very long term in nature and targeted for long term store of value= in contrast to medium of exchange.

I mean, if those use cases are so exciting, it really doesn't seem much=
to ask to see them demoed live on the CTV signet that already exists?

> You can build a CTV vault in signet, but you=E2=80=99ll only really se= e a lot of people using it when it=E2=80=99s to store real value on a time = scale measured in decades not minutes or days

On the other hand, if the value is really "very long term" and th= ere's no
rush to implement these features and demo them ASAP, then it doesn't se= em
like there should be a rush to adapt consensus to these use cases either. Why not wait until someone does have time to finish sketching out the
use case so they can demo them in public?

> To put another way and leave CTV out of it completely, what should an = outside, unbiased observer that doesn=E2=80=99t spend much time on Twitter = expect to be able to see to evaluate the readiness or acceptability of ANYP= REVOUT, TLUV,

For ANYPREVOUT, I would like to see a toy implementation of eltoo using
it, that can handle fees and layered transactions (or has a good argument why layered transactions aren't necessary). It's going to take a wh= ile
even to update LN to taproot and PTLCs though, so eltoo doesn't seem li= ke
it's on the immediate horizon. Besides eltoo, I don't think ANYPREV= OUT
is an optimal design for covenants, so if that was the motivation and
not eltoo, maybe some other approach would be better.

TLUV's design parameters don't really seem optimal (the mess with x= -only
pubkeys, alternatives like OP_EVICT), so I think it's still on the
whiteboard.

Cheers,
aj

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