"Or a really high lock_time, but it would not make it invalid, just
delayed."

Ok, this was a bad idea, since nodes would have to keep it in memory.
Please disregard that idea...

Kalle

Den 27 apr 2015 14:35 skrev "Kalle Rosenbaum" <kalle@rosenbaum.se>:
>
> >
> > Some more use cases might be:
> > Waiting in comfort:
> >  - Send a payment ahead of time, then wander over and collect the goods
> > after X confirmations.
> >
> > Authorized pickup :
> >  - Hot wallet software used by related people could facilitate the use
> > of 1 of N multisig funds.  Any one of the N wallets could collect goods
> > and services purchased by any of the others.
>
> I like this one, because it shows the power of reusing the transaction
data structure.
>
> >
> > Non-monetary gifts:
> >  - Sender exports spent keys to a beneficiary, enabling PoP to work as a
> > gift claim
> >
> > Contingent services:
> >  - Without Bob's permission, a 3rd party conditions action on a payment
> > made from Alice to Bob.  For example, if you donated at least .02 BTC to
> > Dorian, you (or combining scenarios, any of your N authorized family
> > members), can come to my dinner party.
>
> This is an interesting one.
>
> >
> > I tried out your demo wallet and service and it worked as advertised.
> >
> > Could the same standard also be used to prove that a transaction COULD
> > BE created?  To generalize the concept beyond actual payments, you could
> > call it something like proof of payment potential.
>
> I guess it's possible, but we'd have to remove the txid from the output,
since there is none. This is a way of saying "I'm in control of these
addresses". The other party/parties can then verify the funds on the
blockchain and watch those addresses for changes. Maybe there are some
interesting use cases here. Ideas?
>
> >
> > Why not make these proofs permanently INVALID transactions, to remove
> > any possibility of their being mined and spending everything to fees
> > when used in this way, and also in cases involving reorganizations?
>
> Yes. Initially I thought it would be enough that the funds are already
spent, but I think you're right here. Reorgs could be a problem. Worse, you
also might want to prove 0-confirmation transactions, in which case it's a
huge security problem. Someone might intercept the PoP and publish it on
the bitcoin network, spending all the funds. But I still would like wallets
to be able to build/verify PoPs with little or no modifications. Could we
possibly change the version number on the PoP to something other than 1?
Maybe 2^4-1? Or a really high lock_time, but it would not make it invalid,
just delayed. Any suggestions here?
>
> >
> > I agree that PoP seems complementary to BIP70.
> >
> >
>
> Thank you very much for your comments!
>
> /Kalle