PolyD_'s avatar
PolyD_ 2 years ago
CTV and Cold Channels. Today in Bitcoin, to make a channel, you must first receive Bitcoin on-chain and then transfer it to a channel with your partner interactively. This is a minimum of two transactions just to open a channel and the channel opening cannot be batched. With CTV, channels can be hidden inside your pubKey so that when you're paid and the transaction is committed on-chain (can even be batched using only one UTXO), that on-chain commitment is sufficient to use your channel. No need to dump the channel details on-chain. https://image.nostr.build/9c5674ec45bb1c4b1a84c1c1b7223a6223391c8914639cebc09304e2c9f82616.jpg#m=image%2Fjpeg&dim=819x540&blurhash=r89tP%25yUD*M%7CNZV%5BM%7BxuRRGcnhr%3BoInhWBV%40kWWBHbICbrkURQoybYfRox%5EcW%3DNIW%3DS4oLWCjYayucyAVun%2Ct7V%5BahWAV%5B%7DmR.NKWXNIoeW%3BjFWB&x=860ed55345f9f855729c8bf1dfd19accc63cac0b31f90d19fef23c3a444d4263 https://image.nostr.build/f9fd33773a851e375ef91384b005fcddd297a7be2743da20548f69518991c37c.jpg#m=image%2Fjpeg&dim=825x540&blurhash=r67xBu.5RzRjVtRRIUt8xtpPjKRCaixca_V%5Dk8WBDSH%5DIBodx%40tPf%23WXayr%23bWR%24oxoxa%23k9WEf6tGyBtkogaQRQt7WARj%23xWANEk8k7j%5BbXaija&x=3329ea1a5da027f809f762a80c17fb860055934d498ac379894bcc18adbee1a3

Replies (15)

vnprc's avatar
vnprc vnprc@trianglebitdevs.org 2 years ago
Can you explain how CTV allows you to "hide channels inside your pubkey"? I understand CTV lets you precommit to the next transaction, so does this mean your CTV enabled on-chain address is set up to send to a 2-of-2 multisig using another lightning node's pubkey? How is this "inside the pubkey"? In my mental model it is more like you have an extra piece of metadata (the transaction you committed to in your template hash) that lives alongside your pubkey. If you receive two transactions to this address does it necessarily mean you need to open two channels to the same node? What happens if the other node goes offline? Can you spend from your CTV address to anywhere else? How does this work?
PolyD_'s avatar
PolyD_ 2 years ago
It should look like a relatively normal channel except you roll it up into ctv to hide it. It is "cold" since you partner isn't aware of its existence yet. You'll need to coordinate with them to close it efficiently, otherwise you'll have to deal with the time locks. https://image.nostr.build/b56d3ced750e49f4eb52c1b8593031894d6c144c5ad404556c5636b5381cf0a0.jpg#m=image%2Fjpeg&dim=960x540&blurhash=iIGR%7C-0N9b9bbb%251V%3FxZjE%7EVIWIVM%7CV%5Bocj%3Ft6oe00%3FYxp%25Lj%40NHt8WEj%5E01xZsls.jaRnt7bIbIxubHofayWBs%3BfiWBRj&x=49ba0becf3db3d0e8819a2955b8a554b8d9bee2d2bf00ed87012c8a40f161ce4 https://image.nostr.build/51dd64446cab2300f34e507e1856ab57c8b892b56a496b6f42eba3a0c8fc4516.jpg#m=image%2Fjpeg&dim=613x813&blurhash=_OPP_wayxuayxuj%5Bxur%3FfQaefQaefQae.SWBfkayfkaybH9tofoza%7Cozayof%7EqayWBj%5BR*j%5BWB_3WBaefQV%40j%5BWB%253aeV%40jZaej%5Bae%25MayayfQWBj%5BWB%24*aybbfkbHfQbb&x=6faeee704d9c5caaafc379aef0a006568dac29b00085fc8f87dd36b856f6d9b9
1 replies ↓
OT's avatar
OT 2 years ago
Cold channel or pending channel? Why would one do this BTW?
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