Return-Path: Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 5A5EEC000B for ; Wed, 9 Feb 2022 08:53:28 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 3DC65606B0 for ; Wed, 9 Feb 2022 08:53:28 +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: smtp3.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id JD1zSZ3bQT7n for ; Wed, 9 Feb 2022 08:53:27 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.8.0 Received: from mail-lj1-x229.google.com (mail-lj1-x229.google.com [IPv6:2a00:1450:4864:20::229]) by smtp3.osuosl.org (Postfix) with ESMTPS id CFBFC60674 for ; Wed, 9 Feb 2022 08:53:26 +0000 (UTC) Received: by mail-lj1-x229.google.com with SMTP id bx31so2491546ljb.0 for ; Wed, 09 Feb 2022 00:53:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:from:date:message-id:subject:to; bh=NMhaFVFk8ciyyy/otkWIT9WGsBW3mJelcpxKs4Gc43Q=; b=UiPM8evIt3opXGwiYC6lfOATTm+WoW9vI1yipAsvZrUI/nfci1WsBSRMnyw6/TwtXG 8teExlEPu7h/ZzYwKMWEsMdbmlLPbCFLhgD8iHJruyLKb2eT3/TjjzGa+k66nOtKg8Sm IGxuSXOzP4WFCDQk1Dri9vOlWZhBlzSeJEszn0SCLy+7GP6q0MGSSkWvltNydPW6SfLq 74+P6U/72O70hGHdFo/a+rZ54F1x0UixU+3N6eMLrChtspvGCebDYYEt3fikLPp3Gvqi Vthl0OhnxM39Eo5WTJMFB/rO2h0N3QXwvIC/ZnAVTPxy2Sq3nOTDdHX8yuIrK5hd3NXi ydNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=NMhaFVFk8ciyyy/otkWIT9WGsBW3mJelcpxKs4Gc43Q=; b=kBWlshUXdhgMB6dzJT09pqaqGQBjGSYfV1ZkAAlXhL51ig7TpZZvk/XAgXRQEk/eEj N9d9z3AFBtm9X+QTZro31jl8H7ytJt6cCWQfEcAJwYFURpaFeuzlbh39kZmfHQzkhFS8 v0QMsr6nd0/NrLVBfJxc5lq6O4bi/D+uqoU/K8FFcRcTB2aCdcrE689ihzkg+QLisKvy mmuw6YgREbI53xQVcQi8OnJh3DaeHf+4EiXz9OeVQKffZb+z7rK7jegd0fbnbmyx+C5Y PqTHRWeenW95pbQqrSv1gEv55Ha/nA3YIBYYYlF4oqA6M1ixnzeScbYXU3k/3U+RsGmv mt3w== X-Gm-Message-State: AOAM531pRkMtAu4FPW3zuK9wpbUWvByNmniYWI9+zVQFG/UNia5YKZDl 0NpckwDnUDT2e3IsAZLx0RCRAjyg9MCbRHngqvlbyfwyHSK+Ug== X-Google-Smtp-Source: ABdhPJxUmG2BF39BsfS1AWeF2+LB1Bzvbudfd6Hehpy40hexSPU7/3/XynjRdybCaToRS3juoHzjkU/Z88Epj5qIE4s= X-Received: by 2002:a2e:834c:: with SMTP id l12mr872262ljh.81.1644396803728; Wed, 09 Feb 2022 00:53:23 -0800 (PST) MIME-Version: 1.0 From: Jeremy Rubin Date: Wed, 9 Feb 2022 00:53:12 -0800 Message-ID: To: Bitcoin development mailing list Content-Type: multipart/alternative; boundary="0000000000005b27cb05d791f730" Subject: [bitcoin-dev] CTV Meeting Notes #3 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: Wed, 09 Feb 2022 08:53:28 -0000 --0000000000005b27cb05d791f730 Content-Type: text/plain; charset="UTF-8" Bitcoin Developers, The Third CTV meeting was held earlier today (Tuesday February 8th, 2022). You can find the meeting log here: https://gnusha.org/ctv-bip-review/2022-02-08.log A best-effort summary: - Not much new to report on the Bounty - Non Interactive Lightning Channel Opens Non interactive lightning Channel opens seems to work! There are questions around being able operate a channel in a "unipolar" way for routing with the receiver's key offline, as HTLCs might require sync revocation. This is orthogonal to the opening of the channels. - DLCs w/ CTV DLCs built with CTV does seem to be a "key enabler" for DLCs. The non interactivity provides a dramatic speedup (30x - 300x depending on multi-oracle setup) Changes the client/server setup enable new use cases to explore, and simplify the spec substantially. Backfilling lets clients commit to the DLC faster and lazily backfill at cost of state storage. For M-N oracles, precompiling N choose M groups + musig'ing the attestation points can possibly save some witness space because log2(N)*32 + N*32 > log2(N*(N choose M))*32 for many values of N and M. - Pathcoin Not well understood yet concretely. Seems like the API of a "a coin that 1-of-N can spend" shared by N is new/unique and not something LN can do (which always requires N online to sign txns) Binary expansion of coins could allow arbitrary value transfer (binary expansion can live in a CTV tree too). Best way to think of Pathcoin at this point is an important theoretical result that should open up new exploration/improvement - TXHash Main concerns: more complexity, potential for recursion, script size overhead - Soft Forks, Generally Big question: Are the fork processes themselves (e.g., BIP9/8/ST activiations) riskier than the upgrades (CTV)? On the one hand, validation rules are something we have to live with forever so they should be riskier. Soft fork rules and coordination might be bad, but after activation they go away. On the other hand, we can "prove" a technical upgrade correct, but soft-fork signalling requires unprovable user behavior and coordination (e.g., actually upgrading). If you perceive the forking mechanism as high risk, it makes sense to make the upgrades have as much content as possible since you need to justify the high risk. If you perceive the forking mechanism as low risk, it is fine to make the upgrades smaller and easier to prove safe since there's not a high cost to forking. - Elements CTV Emulation Seems to be workable. Questionable if any of the use cases one might want CTV for (Lightning, DLCs, Vaults) would have much demand on Liquid today. Feel free to correct me where I've not represented perspectives decently, as always the logs are the only true summary. Best, Jeremy -- @JeremyRubin --0000000000005b27cb05d791f730 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Bitcoin Developers,
=

The Third CTV meeting was held earlier today (Tuesday February 8th, 2022).= =C2=A0 You can find the meeting log here:=C2=A0https://gnusha.org/ctv-bip-review/2022-02-= 08.log

A best-effort summary:

- Not much new to report on t= he Bounty
- Non Interactive Lightning= Channel Opens
=C2=A0 Non interactive= lightning Channel opens seems to work!
=C2=A0 There are questions around being able operate a channel in a &quo= t;unipolar" way for routing with the receiver's key offline, as HT= LCs might require sync revocation. This is orthogonal to the opening of the= channels.
- DLCs w/ CTV
=C2=A0 DLCs built with CTV does seem to be a &quo= t;key enabler" for DLCs.
=C2=A0 = The non interactivity=C2=A0provides a dramatic speedup (30x - 300x dependin= g on multi-oracle setup)
=C2=A0 Chang= es the client/server setup enable new use cases to explore, and simplify th= e spec substantially.
=C2=A0 Backfill= ing lets clients commit to the DLC faster and lazily backfill at cost of st= ate storage.
=C2=A0 For M-N oracles, = precompiling N choose M groups=C2=A0+ musig'ing the attestation points = can possibly save some witness space because log2(N)*32=C2=A0+ N*32 > lo= g2(N*(N choose M))*32 for many values of N and M.
- Pathcoin
=C2=A0 Not we= ll understood yet concretely.
=C2=A0 = Seems like the API of a "a coin that 1-of-N can spend" shared by = N is new/unique and not something LN can do (which always requires N online= to sign txns)
=C2=A0 Binary expansion of coins could allow arbitrary value transfe= r (binary expansion can live in a CTV tree too).
=C2=A0 Best way to think of Pathcoin at this point is an = important theoretical result that should open up new exploration/improvemen= t
- TXHash
=C2=A0 Main concerns: more complexity, potential for recursion,= script size overhead
- Soft Forks, G= enerally
=C2=A0 Big question: Are the= fork processes themselves (e.g., BIP9/8/ST activiations) riskier than the = upgrades (CTV)?
=C2=A0 On the one han= d, validation rules are something we have to live with forever so they shou= ld be riskier. Soft fork rules and coordination might be bad, but after act= ivation they go away.
=C2=A0 On the o= ther hand, we can "prove" a technical upgrade correct, but soft-f= ork signalling requires unprovable user behavior and coordination (e.g., ac= tually upgrading).
=C2=A0 If you perc= eive the forking mechanism as high risk, it makes sense to make the upgrade= s have as much content as possible since you need to justify the high risk.=
=C2=A0 If you perceive the forking m= echanism as low risk, it is fine to make the upgrades smaller and easier to= prove safe since there's not a high cost to forking.
- Elements CTV Emulation
=C2=A0 Seems to be workable.
=C2=A0 Questionable if any of the use cases one might want CTV for (Ligh= tning, DLCs, Vaults) would have much demand on Liquid today.

Feel fre= e to correct me where I've not represented perspectives decently, as al= ways the logs are the only true summary.

Best,

Jeremy

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