[Lightning-dev] Recovering a channel state

Rusty Russell rusty at rustcorp.com.au
Mon Oct 24 04:11:38 UTC 2016


Anton Kumaigorodskiy <anton.kumaigorodskiy at outlook.com> writes:
> Mobile devices often get lost/stolen/data erased/etc so possibility of
> channel recovering or at least having an ability to break it
> unilaterally on a new device has to be somehow accounted for.

Yes, this is a fun topic!  In particular it's one we deferred for 1.0,
but it's important to discuss.

Let's assume you still have your ID: if you lose that key, you're
screwed.

Tadge has done a lot of work on outsourcing vigilence: uploading
encrypted information to watchers.  This has almost enough information
for you to reconstruct the current state, sufficient to mutually close
the channel.

There's an interesting subset of this, which you could do with your
peers.  Each peer would keep some amount of (encrypted) data for you,
and *always* send it to you whenever you first connect (if you have
to ask for it, that's giving too much away).

As long as one peer is honest, you get enough state to at least cleanly
shutdown the other peers without getting robbed, or, indeed, them
knowing that you had data loss.

There's a lot more work to be done enumerating exactly how this works,
however.

Cheers,
Rusty.


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