A Hash-Timelocked-Contract is a conditional payment on a LN channel with two possible outcomes: Either the recipient provides the pre-image corresponding to the Lightning invoice that is being paid and takes the funds, or after the lock times out, the sender takes back the funds.
Ah submarine swap is an on-chain payment that purchases a LN payment: The sender locks funds into a conditional script, where either the swap provider can spend the funds by providing a pre-image, thus proving to have paid the LN invoice, or sender can take it back themselves.
One of the exciting things is that submarine swaps can be created on most cryptocurrencies, even ones that are not compatible with LN directly. This way you can for example offer to pay some forkcoin to get a LN invoice on the Bitcoin LN paid by ANY swap provider trustlessly.
The talk by @alexbosworth at @SFBitcoinDevs yesterday was filmed, it'll appear on our Youtube channel when done: youtube.com/channel/UCREs0…
