<oembed><type>rich</type><version>1.0</version><title>darosior [ARCHIVE] wrote</title><author_name>darosior [ARCHIVE] (npub1pj…x22xp)</author_name><author_url>https://yabu.me/npub1pj9022f74rzq7d5x7gnxje6wpsgk4r5jgeck8y5awd423ydhan3q7x22xp</author_url><provider_name>njump</provider_name><provider_url>https://yabu.me</provider_url><html>📅 Original date posted:2022-04-25&#xA;📝 Original message:Just a correction to my previous mail. Sorry for the non-attribution, i didn&#39;t recall APO covenants had been discussed in the context of CTV.&#xA;&#xA;&gt; &gt; a write-up that explains how APO-AS w/out ANYONECANPAY approximates CTV?&#xA;&gt;&#xA;&gt; I&#39;m not aware of any specific to CTV. It&#39;s just that the fields covered in the CTV hash are very close to what&#xA;&#xA;The comparison was already done by Anthony Towns.&#xA;https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2019-June/017036.html&#xA;&#xA;Jeremy Rubin already pointed out that it missed committing to the nSequences hash and number of inputs (and optionally scriptSigs).&#xA;https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2019-June/017038.html&#xA;&#xA;&#xA;------- Original Message -------&#xA;Le lundi 25 avril 2022 à 3:35 PM, darosior via bitcoin-dev &lt;bitcoin-dev at lists.linuxfoundation.org&gt; a écrit :&#xA;&#xA;&#xA;&gt; Hi Richard,&#xA;&gt;&#xA;&gt; &gt; Sounds good to me. Although from an activation perspective it may not be either/or, both proposals do&#xA;&gt;&#xA;&gt; compete for scarce reviewer time&#xA;&gt;&#xA;&gt; Yes, of course. Let&#39;s say i was more interested in knowing if people who oppose CTV would oppose&#xA;&gt; SIGHASH_ANYPREVOUT too. I think talking about activation of anything at this point is premature.&#xA;&gt;&#xA;&gt; &gt; For someone not as versed in CTV, why is it necessary that ANYONECANPAY be optional to emulate CTV? Is there&#xA;&gt;&#xA;&gt; a write-up that explains how APO-AS w/out ANYONECANPAY approximates CTV?&#xA;&gt;&#xA;&gt; I&#39;m not aware of any specific to CTV. It&#39;s just that the fields covered in the CTV hash are very close to what&#xA;&gt; ANYPREVOUT_ANYSCRIPT&#39;s signature hash covers [0]. The two things that CTV commits to that APO_AS does not are&#xA;&gt; the number of inputs and the hash of the inputs&#39; sequences [1].&#xA;&gt; Not committing to the number of inputs and other inputs&#39; data is today&#39;s behaviour of ANYONECANPAY that can&#xA;&gt; be combined with other signature hash types [1]. Thus APO_AS makes ACP mandatory, and to emulate CTV&#xA;&gt; completely it should be optional.&#xA;&gt;&#xA;&gt;&#xA;&gt; Antoine&#xA;&gt;&#xA;&gt; [0] https://github.com/bitcoin/bips/blob/master/bip-0119.mediawiki#Detailed_Specification&#xA;&gt; [1] https://github.com/bitcoin/bips/blob/master/bip-0118.mediawiki#signature-message&#xA;&gt; [2] https://github.com/bitcoin/bitcoin/blob/10a626a1d6776447525f50d3e1a97b3c5bbad7d6/src/script/interpreter.cpp#L1327, https://github.com/bitcoin/bitcoin/blob/10a626a1d6776447525f50d3e1a97b3c5bbad7d6/src/script/interpreter.cpp#L1517-L1522&#xA;&gt;&#xA;&gt;&#xA;&gt; ------- Original Message -------&#xA;&gt; Le dimanche 24 avril 2022 à 10:41 PM, Richard Myers remyers at yakshaver.org a écrit :&#xA;&gt;&#xA;&gt;&#xA;&gt;&#xA;&gt; &gt; Hi darosior,&#xA;&gt; &gt;&#xA;&gt; &gt; Thanks for sharing your thoughts on this.&#xA;&gt; &gt;&#xA;&gt; &gt; &gt; I would like to know people&#39;s sentiment about doing (a very slightly tweaked version of) BIP118 in place of&#xA;&gt; &gt; &gt; (or before doing) BIP119.&#xA;&gt; &gt;&#xA;&gt; &gt; Sounds good to me. Although from an activation perspective it may not be either/or, both proposals do compete for scarce reviewer time so their ordering will necessarily be driven by reviewer&#39;s priorities. My priority is eltoo which is why I focus on BIP-118.&#xA;&gt; &gt;&#xA;&gt; &gt; &gt; SIGHASH_ANYPREVOUTANYSCRIPT, if its &#34;ANYONECANPAY&#34; behaviour is made optional [0], can emulate CTV just fine.&#xA;&gt; &gt;&#xA;&gt; &gt; For someone not as versed in CTV, why is it necessary that ANYONECANPAY be optional to emulate CTV? Is there a write-up that explains how APO-AS w/out ANYONECANPAY approximates CTV?&#xA;&gt; &gt;&#xA;&gt; &gt; In the case of eltoo commit txs, we use bring-your-own-fee (BYOF) to late-bind fees; that means ANYONECANPAY will always be paired with APO-AS for eltoo. Settlement txs in eltoo use just APO and do not necessarily need to be paired with ANYONECANPAY.&#xA;&gt; &gt;&#xA;&gt; &gt; I would guess making ANYONECANPAY the default for APO-AS was a way to squeeze in one more sighash flag. Perhaps there&#39;s another way to do it?&#xA;&gt; &gt;&#xA;&gt; &gt; Including SIGHASH_GROUP with APO for eltoo is also tempting. Specifically so the counter-party who commits a settlement tx can use for fees their settled to_self balance. How to rejigger the sighash flags to accommodate both APO and GROUP may be worth some discussion.&#xA;&gt; &gt;&#xA;&gt; &gt; The BIP-118 proposal will certainly benefit from having input from reviewers looking at other protocols than eltoo.&#xA;&gt; &gt;&#xA;&gt; &gt; -- Richard&#xA;&gt;&#xA;&gt; _______________________________________________&#xA;&gt; bitcoin-dev mailing list&#xA;&gt; bitcoin-dev at lists.linuxfoundation.org&#xA;&gt; https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev</html></oembed>