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[202.12.124.146]) by gmr-mx.google.com with ESMTPS id 586e51a60fabf-3f0dd03e80fsi264877fac.6.2025.11.30.06.39.22 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Nov 2025 06:39:22 -0800 (PST) Received-SPF: pass (google.com: domain of pete@petertodd.org designates 202.12.124.146 as permitted sender) client-ip=202.12.124.146; Received: from phl-compute-05.internal (phl-compute-05.internal [10.202.2.45]) by mailfout.stl.internal (Postfix) with ESMTP id EFF591D0013B; Sun, 30 Nov 2025 09:39:21 -0500 (EST) Received: from phl-mailfrontend-01 ([10.202.2.162]) by phl-compute-05.internal (MEProxy); Sun, 30 Nov 2025 09:39:22 -0500 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtdeggddvheehtdelucetufdoteggodetrf dotffvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfurfetoffkrfgpnffqhgenuceu rghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujf gurhepfffhvfevuffkfhggtggujgesghdtroertddtvdenucfhrhhomheprfgvthgvrhcu vfhougguuceophgvthgvsehpvghtvghrthhouggurdhorhhgqeenucggtffrrghtthgvrh hnpedutdffleekiedtfefgteefjefhffeiffevleegtdfhueeffeejveeljeekfefhieen ucffohhmrghinhepphgvthgvrhhtohguugdrohhrghenucevlhhushhtvghrufhiiigvpe dtnecurfgrrhgrmhepmhgrihhlfhhrohhmpehpvghtvgesphgvthgvrhhtohguugdrohhr ghdpnhgspghrtghpthhtohepvddpmhhouggvpehsmhhtphhouhhtpdhrtghpthhtohepvg hkrghgghgrthgrsehgmhgrihhlrdgtohhmpdhrtghpthhtohepsghithgtohhinhguvghv sehgohhoghhlvghgrhhouhhpshdrtghomh X-ME-Proxy: Feedback-ID: i525146e8:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Sun, 30 Nov 2025 09:39:21 -0500 (EST) Received: by localhost (Postfix, from userid 1000) id B5D549FD47; Sun, 30 Nov 2025 14:39:13 +0000 (UTC) Date: Sun, 30 Nov 2025 14:39:13 +0000 From: Peter Todd To: waxwing/ AdamISZ Cc: Bitcoin Development Mailing List Subject: Re: [bitcoindev] A safe way to remove objectionable content from the blockchain Message-ID: References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="kwfBOgwfTg9l5ChO" Content-Disposition: inline In-Reply-To: X-Original-Sender: pete@petertodd.org X-Original-Authentication-Results: gmr-mx.google.com; dkim=pass header.i=@messagingengine.com header.s=fm1 header.b=EUgyQSNE; spf=pass (google.com: domain of pete@petertodd.org designates 202.12.124.146 as permitted sender) smtp.mailfrom=pete@petertodd.org 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: -0.8 (/) --kwfBOgwfTg9l5ChO Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline On Sat, Nov 29, 2025 at 05:54:13AM -0800, waxwing/ AdamISZ wrote: > Hi Peter, list, > > Interesting! > > One thought that springs to mind: attempts to ameliorate IBD with ZKP > should not forget one thing: what we actually want here is succinctness, > and not so much ZK. Think SNARK instead of ZkSNARK. > Which is important; without the requirement for an actual ZK property for > the protocol, you can have it have attached witness that is not secret. The Zero-Knowledge part is important to the goal in this specific use-case: trying to prevent all arbitrary data publication. > Then a counter-thought strikes, that any version of these protocols that > requires more data/bandwidth probably loses out to versions that have less > data/bandwidth. Hmm. Ecash has even less data/bandwidth than Bitcoin. Yet people choose not to use weaker security assumptions in favor of stronger security assumptions. > I do think, long term that ZKP over history is correct, and that (see > typical rollup design) data carrying in state can do the job that you are > (correctly) insisting, must be done. > (And the corollary: "harmful data on the blockchain" is a wrong mental > model and should be abandoned, irrespective of architecture.) It's quite possible that ZKP's are, in the context of decentralized blockchains, an exploit that will prove to be impossible to patch. Similar to how merge mining is an economic exploit that may well be impossible to patch. Sometimes seemingly good ideas are ultimately killed by clever exploits. > Aside from your *main* concept here, I think the idea that HTLCs require > *proof* of publication is wrong. What they require is publication. A > wronged channel party needs to read the preimage, not have proof that it > can be read. That is not correct. If Alice offers a HTLC to Bob, Alice needs proof that in the event of a redemption, Bob is forced to publish the preimage in such a way that Alice can recover it. The *proof* aspect of this is critical to the security model. It's not enough that Bob merely promise to give the preimage to Alice: redemption must be atomic with publication. > Take as contrast the opentimestamps model, where having proof > that something was published, is the main functionality offered/required. Nope. OpenTimestamps does not use proof of publication at all. OpenTimestamps is a commitment operation: proof that if A was changed, B would have to change too. The vast majority of OTS timestamps are for private data that is never published in any way. OTS simply shows that data *existed*. > I > suppose there is another way to say it: the channel counterparty needs > "proof of future publication" in contract setup. That's fair enough but > it's a very different thing than getting a proof that something *was* > published. It is not a meaningfully different thing. An HTLC is proof that in the event of an uncooperative redemption, publication will happen. Slightly changing the time it takes is irrelevant to the general concept. Concretely: unless you can propose a technical innovation that somehow turns this pedantic nuance into a meaningfully different implementation, so what? -- https://petertodd.org 'peter'[:-1]@petertodd.org -- 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/bitcoindev/aSxXEZzEAlfxLYlY%40petertodd.org. --kwfBOgwfTg9l5ChO Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE0RcYcKRzsEwFZ3N5Lly11TVRLzcFAmksVwgACgkQLly11TVR Lze90g/+JXChc4Ahr7h0ay+7Oj2gDCslaCJkEY2sv6gHJrT0awvAfoMjHm+wLP6X L90xhFEtAlbMTmYf/R8p+70X7pj8D6T+cTr8TnzflakFIn97OGhmlrm6dE/OwpkR 8KkMboeaC2jljU39jB/2MgGT2QAvEM2seHN+L43WvfUQjgfAuscHudevLPu913an VlGMF+Z2yFTS0Dv9ggbfz7leT6ExPyuv60J8p+iXw8xSdxRLZpuiAesO0pcj48cO AJqFrGy5+/HbnZCp5N/hZhf/RTJGI1Go8y1L35vy7rkg/ZLGzw8KOfME3QwMPPZp mu37G/HoahUVIRC+GBEUkzCXivK04fGOkp1vM6VWd7AI5FnwIIqLRAtGN1CQ+Xrs UFlM6p+gs6FjpzmSzIH5V0kg5WrmvlFaQjPcBajMFvGDLWF6iAdu7u5zpjCwbmFF Z8LBgJUkrCkXRqTT+EUrr3cBYbS10eUrgybEwQkSJ79E60U0kMkUP3x/Coby+pgZ o+1z5EnEXzj01FkkXK/KJdGkicAyHtBS0ZswYeCiaWJoCshsA/C+mizO0pU9ZH0d nVd7qjR+3XOxSqYpLtEAqikZXbItV2+m4zhgufcFDrdVoq7Kb8DOzRGSY3n9zfla +lN2vImuEOW20cdrcGVJl7TPWXCXV5FoDeB1SMxui4hIxAcW95s= =5mBl -----END PGP SIGNATURE----- --kwfBOgwfTg9l5ChO--