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[79.135.106.31]) by gmr-mx.google.com with ESMTPS id ffacd0b85a97d-3a5323f0a6bsi177376f8f.3.2025.06.09.11.55.21 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Jun 2025 11:55:21 -0700 (PDT) Received-SPF: pass (google.com: domain of darosior@protonmail.com designates 79.135.106.31 as permitted sender) client-ip=79.135.106.31; Date: Mon, 09 Jun 2025 18:55:15 +0000 To: James O'Beirne From: "'Antoine Poinsot' via Bitcoin Development Mailing List" Cc: Bitcoin Development Mailing List Subject: Re: [bitcoindev] CTV + CSFS: a letter Message-ID: In-Reply-To: References: Feedback-ID: 7060259:user:proton X-Pm-Message-ID: df7e2488c83d37d35276af506a88ae6b692b07d3 MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Original-Sender: darosior@protonmail.com X-Original-Authentication-Results: gmr-mx.google.com; dkim=pass header.i=@protonmail.com header.s=protonmail3 header.b=o8WrDvWd; spf=pass (google.com: domain of darosior@protonmail.com designates 79.135.106.31 as permitted sender) smtp.mailfrom=darosior@protonmail.com; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=protonmail.com X-Original-From: Antoine Poinsot Reply-To: Antoine Poinsot Precedence: list Mailing-list: list bitcoindev@googlegroups.com; contact bitcoindev+owners@googlegroups.com List-ID: X-Google-Group-Id: 786775582512 List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , X-Spam-Score: -1.0 (-) James, cosigners, I am sympathetic to the idea of a CTV+CSFS soft fork, mainly for its flagsh= ip use case: LN-Symmetry. However i think it is premature to call for a "final review and activation"= of these opcodes when there is still: - disagreement between Bitcoin protocol developers/researchers that it is t= he way to go for enabling more expressive scripting capabilities in Bitcoin[^0]; - disagreement between Bitcoin developers on how the functionality of at le= ast one of the proposed opcodes should be achieved[^1]; - no review after three months, from any of the champions or signers of thi= s letter, on the PR for integrating one of the two proposed opcodes to the test network[^2]. The flagship use case of the proposal has also not been properly demonstrat= ed. As a point of comparison Greg Sanders provided motivation for `ANYPREVOUT`, a soft fork t= hat no one even called to be "finally reviewed and activated", by publishing a detailed proof of c= oncept of LN-Symmetry (with full specification as a BOLT draft + an implementation in one of the = major Lightning clients). A comprehensive exploration gives confidence a use case is actually realist= ic in practice. Of course it's not necessary to go to such lengths just to demonstrate it to be *poss= ible*, but it is reasonable to expect a champion to have something to show if they are calli= ng for changing Bitcoin. Fortunately i hear some have taken upon themselves to further explore LN-Sy= mmetry and multiparty channels using CTV+CSFS, which could provide tangible motivation for the so= ft fork. Let's see what they come up with. Finally, it seems the post contains a built-in assumption that Bitcoin Core= contributors are detached from the research in more expressive scripting capabilities. It is= incorrect. A number of individuals have been involved both with Bitcoin Core development and Bitco= in protocol research, with substantial contributions in both areas. Therefore it seems the stalling state of the CTV+CSFS proposal is not due t= o apathy as this open letter would lead to believe, but controversy on the content of the proposa= l among Bitcoin protocol developers as well as a lack of involvement from the part of champions in r= eaching consensus. In these conditions calling for an impending change to Bitcoin's consensus = rules seems unadvisable, and the urgency with a six months deadline is nothing short of reckless. I remain confident we can make progress toward enabling more expressive scr= ipting capabilities in Bitcoin. The path forward is by building consensus on the basis of strong t= echnical arguments, and the politics of pushing for the premature activation of a consensus change = are working against it. Best, Antoine Poinsot [^0]: https://delvingbitcoin.org/t/ctv-csfs-can-we-reach-consensus-on-a-fir= st-step-towards-covenants/1509/14 https://gnusha.org/pi/bitcoindev/6f78b702-4bd0-4aa4-ac51-b881d8df9f01= @mattcorallo.com [^1]: https://delvingbitcoin.org/t/ctv-csfs-can-we-reach-consensus-on-a-fir= st-step-towards-covenants/1509/58 [^2]: https://github.com/bitcoin-inquisition/bitcoin/pull/72 [^3]: https://delvingbitcoin.org/t/ln-symmetry-project-recap/359 On Monday, June 9th, 2025 at 7:54 AM, James O'Beirne wrote: > Good morning, >=20 > A letter has been published advocating for the final review and > activation of OP_CHECKTEMPLATEVERIFY (BIP-119) and OP_CHECKSIGFROMSTACK > (BIP-348). >=20 > The full text of the letter can be found at https://ctv-csfs.com. It is > reproduced below. >=20 > --- >=20 > To the technical bitcoin community, >=20 > We believe that the best next step for bitcoin would be to activate > OP_CHECKTEMPLATEVERIFY (CTV, BIP-119) and OP_CHECKSIGFROMSTACK (CSFS, > BIP-348). These opcodes enable functionality for a broad set of uses > that will allow bitcoin to preserve and expand its role as a scarce, > censorship-resistant store of value. >=20 > While there are a few promising proposals to improve bitcoin at the > consensus layer which may someday be deployed, we believe that CTV and > CSFS are uniquely well reviewed, simple, and have been proven to be both > safe and widely demanded. >=20 > CTV was first formalized in BIP-119 over 5 years ago. Despite many > attempts at refinement or replacement, it has remained the most widely > preferred method for enforcing pregenerated transaction sequences using > consensus. It unlocks valuable functionality for scaling solutions, > vaults, congestion control, non-custodial mining, discreet log > contracts, and more. >=20 > CSFS is a primitive opcode that has been deployed to Blockstream=E2=80=99= s > Elements for at least 8 years. It represents no significant > computational burden over bitcoin=E2=80=99s most often used opcode, OP_CH= ECKSIG. > It can be combined with CTV to implement ln-symmetry, a longstanding > improvement to Lightning. It also unlocks a variety of other use cases. >=20 > We respectfully ask Bitcoin Core contributors to prioritize the review > and integration of CTV (PR #31989 or similar) and CSFS (PR #32247 or > similar) within the next six months. We believe this timeline allows for > rigorous final review and activation planning. >=20 > This request isn't meant to suggest that these contributors dictate the > consensus process, but rather it is an acknowledgement that before these > opcodes can be activated, they must be implemented in the most widely > used bitcoin client. >=20 > As application and protocol developers, we are convinced of the > significant benefits that these changes would bring to end users of > bitcoin =E2=80=93 even if only considering their use for layer 1 security= and > layer 2 scaling solutions. We are optimistic that given the limited size > and scope of these changes in both concept and implementation, they > represent a realistic next step in the continuing and important work of > preserving bitcoin's unique promise. >=20 > Signed, >=20 > Abdel (Starkware) > Andrew Poelstra (@apoelstra) > Ben Carman (@benthecarman) > Ben Kaufman (@ben-kaufman) > Brandon Black (@reardencode) > Brian Langel (for Five Bells) > Buck Perley (@puckberley) > Calle (Cashu) > Calvin Kim (@kcalvinalvin) > Chun Wang (f2pool) > Christian Decker (@cdecker) > Coinjoined Chris (Bitsurance.eu) > Evan Kaloudis (for Zeus) > fiatjaf (@fiatjaf) > Floppy (@1440000bytes) > Gary Krause (@average-gary) > Harsha Goli (@arshbot) > Hunter Beast (@cryptoquick) > Jad Mubaslat (@champbronc2) > James O=E2=80=99Beirne (@jamesob) > Jameson Lopp (@jlopp) > Johan Halseth (@halseth) > Luke Childs (@lukechilds) > Matt Black (for Atomic Finance) > Michael Tidwell (@miketwenty1) > Nick Hansen (for Luxor Mining) > Nitesh (@nitesh_btc) > nvk (@nvk) > Owen Kemeys (for Foundation) > Paul Sztorc (@psztorc) > Portland.HODL (for MARA Pool) > Rijndael (@rot13maxi) > Rob Hamilton (@rob1ham) > Robin Linus (@RobinLinus) > Sanket Kanjalkar (@sanket1729) > Sean Ryan (Anchorage) > Seth for Privacy (for Cake Wallet) > Simanta Gautam (Alpen Labs) > Steven Roose (@stevenroose) > stutxo (@stutxo) > Talip (@otaliptus) > mononaut (@mononautical) > vnprc (@vnprc) >=20 >=20 > -- > You received this message because you are subscribed to the Google Groups= "Bitcoin Development Mailing List" group. > To unsubscribe from this group and stop receiving emails from it, send an= email to bitcoindev+unsubscribe@googlegroups.com. > To view this discussion visit https://groups.google.com/d/msgid/bitcoinde= v/a86c2737-db79-4f54-9c1d-51beeb765163n%40googlegroups.com. --=20 You received this message because you are subscribed to the Google Groups "= Bitcoin Development Mailing List" group. 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