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From: Andreas Schildbach <andreas@schildbach.de>
To: bitcoin-development@lists.sourceforge.net
Subject: Re: [Bitcoin-development] Payment Protocol for Face-to-face Payments
Date: Fri, 21 Mar 2014 10:47:03 +0100	[thread overview]
Message-ID: <lgh1q8$1dc$1@ger.gmane.org> (raw)
In-Reply-To: <CALDj+BZRsXnU5w=1B+01PDfMPY-7zqU3GP_52vr9wknEdTJ59Q@mail.gmail.com>

On 03/20/2014 05:14 PM, Alex Kotenko wrote:

> Hmm, if we're inventing an URI for bluetooth, I'd rather follow existing
> URI's patterns. BT is strictly point-to-point connection, so BT MAC
> should be considered as server address, and payment request ID can be
> considered as request path. Probably "bt:<bt-mac>/​
> <random_id_of_payment_request>" would be more usual and easily
> understandable.

Agreed. I used the dash because I feared a slash would need to be
escaped if used in an URL parameter.

> I wonder how complex it would be to implement HTTP-over-Bluetooth. Not
> like I'm willing to do that now, but HTTP is well known and proven to be
> quite good for tasks like this, so in theory it would be handy to have
> such capacities in here.

Thought of that as well. On the other hand, HTTP might be overkill and
we inherit its potential downsides as well.

>     Well, do we need to be compatible? If the dev community decides Base43
>     PR QR's (or whatever other self-contained format) is the way to go, we
>     just implement, roll it out and use it.
> 
> My PoS needs to be compatible with BIP21, as when I'm presenting QR code
> or sending NFC message - I have no way to tell what wallet/phone is ​​on
> the accepting side, so I have to be compatible to existing widely
> supported technologies.

Agreed. All I wanted to say support for QR is still small enough that we
might be able to switch to an incompatible standard. If we're determined
that is.

> ​Well, yes, it would be less efficient than base43. But did you
> calculate how much less? ​It's a compatible and already widely used way
> and loosing compatibility needs to have serious reasons, so would be
> great to know exact figures here.

Base 64 via binary QR:   64 chars / 256 chars
                         ==> 6 bit / 8 bit = 0.75

Base 43 via alphanum QR: 43 chars / 45 chars
                         ==> 5.43 bit / 5.49 bit = 0.99

That would be efficiency in terms of PR data size vs. amount space used
in a QR code. Of course, the visual QR encoding also plays a role, for
example its size is increased in discrete steps.





  reply	other threads:[~2014-03-21  9:47 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-27 11:59 [Bitcoin-development] Payment Protocol for Face-to-face Payments Andreas Schildbach
2014-01-27 13:11 ` Mike Hearn
2014-01-27 18:18   ` Andreas Schildbach
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 [this message]
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

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