On Wed, Jul 14, 2021 at 04:44:24PM +0200, Christian Decker wrote: > Not quite sure if this issue is unique to eltoo tbh. While in LN-penalty > loss-of-state equates to loss-of-funds, in eltoo this is reduced to > impact only funds that are in a PTLC at the time of the loss-of-state.
Well, the idea (in my head at least) is it should be "safe" to restore an eltoo channel from a backup even if it's out of date, so the question is what "safe" can actually mean. LN-penalty definitely isn't safe in that scenario. > 2) Use the peer-storage idea, where we deposit an encrypted bundle with > our peers, and which we expect the peers to return. by hiding the fact > that we forgot some state, until the data has been exchanged we can > ensure that peers always return the latest snapshot of whatever we gave > them. I don't think you can reliably hide that you forgot some state? If you _did_ forget your state, you'll have forgotten their latest bundle too, and it seems like there's at least a 50/50 chance you'd have to send them their bundle before they sent you yours? Sharing with other peers has costs too -- if you can't commit to an updated state with peer A until you've sent the updated data to peers B and C as backup, then you've got a lot more latency on each channel, for example. And if you commit first, then you've got the problem of what happens if you crash before the update has made it to either B or C? But I guess what I'm saying is sure -- those are great ideas, but they only reduce the chance that you'll not have the latest state, they don't eliminate it. But it seems like it can probably be reduced enough that it's fine that you're risking the balances in live HTLCs (or perhaps HTLCs that have been initiated since your last state backup), as long as you're at least able to claim your channel balance from whatever more recent state your peers may have. Cheers, aj _______________________________________________ Lightning-dev mailing list Lightning-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/lightning-dev
