{"type":"rich","version":"1.0","title":"Anthony Towns [ARCHIVE] wrote","author_name":"Anthony Towns [ARCHIVE] (npub17r…x9l2h)","author_url":"https://yabu.me/npub17rld56k4365lfphyd8u8kwuejey5xcazdxptserx03wc4jc9g24stx9l2h","provider_name":"njump","provider_url":"https://yabu.me","html":"📅 Original date posted:2021-10-08\n📝 Original message:\nOn Sat, Oct 09, 2021 at 01:49:38AM +0000, ZmnSCPxj wrote:\n\u003e A transaction is required, but I believe it is not necessary to put it *onchain* (at the cost of implementation complexity in the drop-onchain case).\n\nThe trick with that is that if you don't put it on chain, you need\nto calculate the fees for it in advance so that they'll be sufficient\nwhen you do want to put it on chain, *and* you can't update it without\ngoing onchain, because there's no way to revoke old off-chain funding\ntransactions.\n\n\u003e This has the advantage of maintaining the historical longevity of the channel.\n\u003e Many pathfinding and autopilot heuristics use channel lifetime as a positive indicator of desirability,\n\nMaybe that's a good reason for routing nodes to do shadow channels as\na matter of course -- call the currently established channel between\nAlice and Bob \"C1\", and leave it as bolt#3 based, but establish a new\ntaproot based channel C2 also between Alice and Bob. Don't advertise C2\n(making it a shadow channel), just say that C1 now supports PTLCs, but\nsecretly commit to those PTLCs to C2 instead C1. Once the C2 funding tx\nis buried enough, start advertising C2 instead taking advantage of its\nnow sufficiently buried funding transaction, and convert C1 to a shadow\nchannel instead.\n\nIn particular, that setup allows you to splice funds into or out of the\nshadow channel while retaining the positive longevity heuristics of the\npublic channel.\n\nCheers,\naj"}