Lightning transactions with v3 and ephemeral anchors

[morehouse]

@t-bast

@morehouse

Yeah, we’d need a new message to transmit HTLC signatures prior to the commitment signature.

My gut feeling is that we should wait for PTLCs to do this work, because we most likely need something similar for PTLC to exchange partial signatures (as detailed in my old writeup with the commitment_proposed message).

Cool! With the approach in your writeup, it looks like we can simply make the Claim-PTLC-Success transactions v3, with no other changes required.

Seems like a great way to kill two birds with one stone.