[Lightning-dev] Payment and Refund Stuck

Joseph Poon joseph at lightning.network
Thu Sep 24 20:52:52 UTC 2015

Hi Mats,

Yes, I agree whole heartedly! See my related comment here:

Two hashes are necessary for this type of invalidation.

On Thu, Sep 24, 2015 at 03:26:30PM +0930, Rusty Russell wrote:
> Mats Jerratsch <matsjj at gmail.com> writes:
> > So far my impression was that an attacker that only stops one payment
> > is just a nuisance, as the system can self-correct. The payer and
> > payee can set a timeout. If the payment has not arrived after the
> > timeout the payee can issue a refund back to the payer. The refund
> > will pay to the same secret hash as the initial payment, and it will
> > pay an amount that is sufficient such that the payer will receive his
> > initial payment completely back. (That is, he might end up paying more
> > refund than actual payment)
> >
> > When the payer does receive the refund in his channel, he can be sure
> > that the payment got invalidated. The payee must not reveal the
> > secret, and even if he does, the funds will just circle back again.
> > (plus the payee will pay fees for both transactions as a disincentive)
> > This concept has been around already, at least I read it somewhere.
> Yes, I think it was Joseph Poon who suggested it.  I'm keeping it in
> reserve for the moment, in case this becomes common enough that we need
> to code up a solution.

Yes, seems like something to tack on later.

Joseph Poon

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