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From: Kalle Rosenbaum <kalle@rosenbaum.se>
To: Tom Harding <tomh@thinlink.com>
Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Proof of Payment
Date: Mon, 27 Apr 2015 14:35:27 +0200	[thread overview]
Message-ID: <CAPswA9xUfr1D6New3hm+1Z1OqSfkAZ8L+VnbFZayG+uJecgaeA@mail.gmail.com> (raw)
In-Reply-To: <553D87CE.5000005@thinlink.com>

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>
> 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

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  reply	other threads:[~2015-04-27 12:35 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-13 19:29 [Bitcoin-development] Proof of Payment Kalle Rosenbaum
2015-03-13 20:30 ` Natanael
2015-03-13 21:31 ` Mike Hearn
2015-03-13 21:47   ` Kalle Rosenbaum
2015-03-13 22:03     ` Mike Hearn
     [not found]       ` <CAPswA9y5bDs1urRCmh8Oxeho4As8pBt2rRVP6fjhjJA0cZrvfA@mail.gmail.com>
     [not found]         ` <CANEZrP35_h_-2c=A-1+M8umSpAC70DJ7sYhPPo_62dm2QKHCEg@mail.gmail.com>
2015-03-14  9:28           ` Kalle Rosenbaum
     [not found] ` <A2849710-1069-45A1-89C0-9D8E40C4A8D6@newcastle.ac.uk>
2015-03-14 18:16   ` Kalle Rosenbaum
2015-04-22 20:03     ` Kalle Rosenbaum
     [not found]       ` <55384AC9.80501@datamagi.no>
2015-04-23 14:39         ` Kalle Rosenbaum
2015-04-27  0:50       ` Tom Harding
2015-04-27 12:35         ` Kalle Rosenbaum [this message]
2015-04-27 12:41           ` Kalle Rosenbaum
2015-04-28  7:23             ` Jorge Timón
2015-04-28 12:41               ` Kalle Rosenbaum
2015-04-28 12:53                 ` Jorge Timón

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