From laolu32 at gmail.com Mon Aug 7 19:25:48 2017 From: laolu32 at gmail.com (Olaoluwa Osuntokun) Date: Mon, 07 Aug 2017 19:25:48 +0000 Subject: [Lightning-dev] Minutes of Dev Meeting 2017-07-10 In-Reply-To: <871soyqye7.fsf@rustcorp.com.au> References: <874ltuqz1u.fsf@rustcorp.com.au> <871soyqye7.fsf@rustcorp.com.au> Message-ID: > I think it does already: Yep! An oversight on my part. > So, you're suggesting SIGHASH_SINGLE|SIGHASH_ANYONECANPAY? Precisely. The code modifications required to switch to this signing mode are trivial. > though it's a pretty obscure case where we want to close out many HTLCs at > once; this is more for fee bumping I think. Well it's for both. In the case of a commitment transaction broadcast (for what ever reason) each party is able to group together HTLC's expiring around the same height (in the case that the pre-image for a bunch was never revealed. This leads to less transactions on-chain, and lower fees cumulative for either side to sweep all funds back into their primary wallet. The fee bumping use case is also a bonus! On Sat, Jul 29, 2017 at 10:36 PM Rusty Russell wrote: > Rusty Russell writes: > > > > https://docs.google.com/document/d/1ng6FaOLGS7ZQEsv3kn6W-t2GzQShhD7eFPz-1yFQZm0/edit?usp=sharing > > Some feedback, since I missed what seems like a very productive > discussion! > > > HTLC floor created by second-level HTLC transactions > > Pierre points out that should choose HTLC min high enough that don?t run > into issues. > > Laolu points out this means that unable to send and claim small-ish > amounts chain. > > Laolu points out that would basically CREATE a dust output in the > process. > > LAOLU SUGGESTS THAT TRIM OUTPUT SPEC PORTION SHOULD ALSO SAY DON?T > CREATE DUST OUTPUT ON SECOND LEVEL TX > > I think it does already: > > For every offered HTLC, if the HTLC amount minus the HTLC-timeout fee > would be less than `dust_limit_satoshis` set by the transaction owner, > the commitment transaction MUST NOT contain that output > > (Similarly for received HTLCs) > > ie. don't create HTLC outputs which would need an HTLC tx with a dust > output. > > > Don?t use sighash-all on the second-level HTLC transactions > > Laolu points out that this would allow us to coalesce many HTLC > > transactions into a single one. Saves on-chain foot print, and also > > allows to add more fees. Basically like ?Lighthouse? (by hearn). > > So, you're suggesting SIGHASH_SINGLE|SIGHASH_ANYONECANPAY? > > I *think* this would work, though it's a pretty obscure case where we > want to close out many HTLCs at once; this is more for fee bumping I > think. > > There are two other cases where we don't rely on the TXID, and such an > approach would be possible: > > 1. Commitment tx with no HTLC outputs. > 2. The closing transaction. > > Cheers, > Rusty. > -------------- next part -------------- An HTML attachment was scrubbed... URL: