From: Andreas Schildbach <andreas@schildbach•de>
To: bitcoin-development@lists•sourceforge.net
Subject: Re: [Bitcoin-development] Payment Protocol for Face-to-face Payments
Date: Mon, 27 Jan 2014 19:18:11 +0100 [thread overview]
Message-ID: <lc67sl$h3$1@ger.gmane.org> (raw)
In-Reply-To: <CANEZrP3POX5SACS18_rrQxx=mzmthrM418zmd8Z7-5CBNFSW4Q@mail.gmail.com>
On 01/27/2014 02:11 PM, Mike Hearn wrote:
> I would like to see Bluetooth continue to work for scan-to-pay even in
> the signed case. So for this reason the current approach with a BTMAC
> parameter in the Bitcoin URI seems to work universally across NFC tags
> and QR codes, and would allow download of a signed PaymentRequest even
> in the case where a QR code is used.
I'm not saying I'm against signed payment requests, but unfortunately
they are just too big for QR-codes. Then again, QR-codes *can* take up
to 2 KB. How big would a very basic trust chain plus signature be?
> Because a Bitcoin URI already contains a public key (hash), re-using
> that to establish an encrypted/authd connection on top of an insecure
> RFCOMM socket would seem to be relatively straightforward.
I was under the impression that addresses will go away. Can you
elaborate on the mechanism?
> Obviously such QR-encoded payment requests cannot grow in size as much
> as using other media. In particular, I expect PKI signed requests are
> out of question. However, in face to face payments the value of a sig
> based on PKI is highly questionable, and the fact the sig cannot be
> verified without TCP connectivity doesn't help.
>
> Just a correction here - the reason signed payment requests are "large"
> (about 4000 bytes) is exactly because they *can* be verified offline,
> i.e. by a Trezor. The signed payment request contains all the data
> needed to establish its authenticity, including certificates and the
> signature itself. No TCP connection is needed.
Ok, that's good news (to me). However, you are going to manage trust
stores (adding and revoking) without TCP?
> For face to face payments, I think signing is still useful. For one, we
> want to keep the distinction between "merchant" and "user" as blurry and
> indistinct as possible. A strong separation between merchants and
> consumers is one of the many bad things about the credit card system.
Ack.
> Whilst initially we'd expect the payment protocol to be used by online
> webshops, in future it could be used by little corner shops, children's
> lemonade stands and so on.
Well I'm thinking the other way round. Use Bitcoin where its already
used today -- face to face.
> you probably still would like a receipt if you buy
> something from a local market trader.
Yes, but where is the problem?
> Another use case - we heard a story about a restaurant owner who
> accepted Bitcoin. He printed a static bitcoin URI onto a QR code on the
> menu. A month or two later he discovered one of his waiters had
> re-printed the menus with his own QR code! The people thought they had
> been paying for the meal, and in fact it went right into the pocket of
> the waiter.
Sad story, but it's really a special case. Using a printed QR-code is
clearly the wrong tool for his task, for several reasons.
And again, how is he going to provide the payment request to the payer
without TCP?
> As to how it works, well, that's not hard. Comodo give away free email
> address certs with a few mouse clicks, it's no harder than signing up
> for a website.
We don't want to force people to sign up anywhere. Bitcoin is instant-on.
> - I chose to re-use the "bitcoin:" URL scheme
>
> Other wallets won't know what to do with it and would yield a strange
> error message.
Which is why I said we need some transition time.
> Rather than pack a file into a URL, if you don't want to
> use the current r= extension it's better for apps to just register to
> handle .bitcoinpaymentrequest files / the right MIME type. Downloading
> it and opening it would do the right thing automatically.
That's a good point. I'll implement this asap.
> Remember BIP 73 also! It says that with the apps built-in QR scanner, if
> you scan an HTTP[S] URI, you should try downloading it with a magic
> header. That way you can get a payment request file out of the server.
> Without the magic header (i.e. a normal generic barcode scanner app) it
> would open a web page containing a bitcoin URI clickable link.
Interesting, did not know about this BIP. However I don't understand the
usecase. Its not like my browsers always display QR-codes with URL of
the page being shown. And if the page in question bothers to show a QR
code, it could just as well also link to a payment request resource (as
suggested above).
next prev parent reply other threads:[~2014-01-27 18:18 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-27 11:59 Andreas Schildbach
2014-01-27 13:11 ` Mike Hearn
2014-01-27 18:18 ` Andreas Schildbach [this message]
2014-01-27 18:34 ` Mike Hearn
2014-01-27 20:53 ` [Bitcoin-development] Experiment with linking payment requests via href Andreas Schildbach
2014-01-27 21:47 ` Mike Hearn
2014-01-27 17:11 ` [Bitcoin-development] Payment Protocol for Face-to-face Payments Jeremy Spilman
2014-01-27 17:39 ` Andreas Schildbach
2014-01-27 18:18 ` Jeremy Spilman
2014-01-27 20:34 ` Roy Badami
2014-01-29 14:57 ` Christophe Biocca
2014-01-30 10:46 ` Andreas Schildbach
2014-01-30 10:50 ` Mike Hearn
2014-02-07 23:15 ` Andreas Schildbach
2014-03-02 9:47 ` Andreas Schildbach
2014-03-02 11:50 ` Mike Hearn
2014-03-20 2:22 ` Alex Kotenko
2014-03-20 3:31 ` Jeff Garzik
2014-03-20 8:09 ` Andreas Schildbach
2014-03-20 10:36 ` Mike Hearn
2014-03-20 12:12 ` Adam Back
2014-03-20 12:20 ` Mike Hearn
2014-03-20 17:31 ` Jeff Garzik
2014-03-20 17:42 ` Alex Kotenko
2014-03-20 18:01 ` Jeff Garzik
2014-03-21 10:28 ` Andreas Schildbach
2014-03-21 13:59 ` Alex Kotenko
2014-03-22 16:35 ` Jeff Garzik
2014-03-22 16:45 ` Mike Hearn
2014-03-22 16:55 ` Mark Friedenbach
2014-03-22 17:24 ` Jeff Garzik
2014-03-22 17:30 ` Mike Hearn
2014-03-23 3:47 ` Alex Kotenko
2014-03-21 10:25 ` Andreas Schildbach
2014-03-21 10:59 ` Adam Back
2014-03-21 11:08 ` Mike Hearn
2014-03-21 11:33 ` Mike Hearn
2014-03-21 12:25 ` Adam Back
2014-03-21 13:07 ` Mike Hearn
2014-03-20 18:20 ` Alex Kotenko
2014-03-20 18:31 ` Mike Hearn
2014-03-20 18:50 ` Alex Kotenko
2014-03-20 21:52 ` Roy Badami
2014-03-20 23:02 ` Mike Hearn
2014-03-26 22:48 ` Roy Badami
2014-03-26 22:56 ` Mike Hearn
2014-03-26 23:20 ` Andreas Schildbach
2014-03-27 10:08 ` Mike Hearn
2014-03-27 13:31 ` vv01f
2014-06-30 19:26 ` Alex Kotenko
2014-07-01 8:18 ` Mike Hearn
2014-07-01 9:48 ` Andreas Schildbach
2014-07-01 10:42 ` Michael Wozniak
2014-07-01 13:03 ` Alex Kotenko
2014-07-01 14:59 ` Andreas Schildbach
2014-07-01 15:07 ` Michael Wozniak
2014-07-01 15:39 ` Andreas Schildbach
2014-07-01 17:18 ` Alex Kotenko
2014-07-01 17:59 ` Mike Hearn
2014-07-02 8:49 ` Alex Kotenko
2014-03-21 10:43 ` Andreas Schildbach
2014-03-20 8:08 ` Andreas Schildbach
2014-03-20 16:14 ` Alex Kotenko
2014-03-21 9:47 ` Andreas Schildbach
2014-03-21 13:54 ` Alex Kotenko
2014-03-21 14:51 ` Andreas Schildbach
2014-03-21 15:38 ` Alex Kotenko
2014-03-21 15:20 ` Andreas Schildbach
2014-03-21 15:24 ` Mike Hearn
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='lc67sl$h3$1@ger.gmane.org' \
--to=andreas@schildbach$(echo .)de \
--cc=bitcoin-development@lists$(echo .)sourceforge.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox