From: Adam Back <adam@cypherspace•org>
To: Andreas Schildbach <andreas@schildbach•de>
Cc: bitcoin-development@lists•sourceforge.net
Subject: Re: [Bitcoin-development] Payment Protocol for Face-to-face Payments
Date: Fri, 21 Mar 2014 11:59:06 +0100 [thread overview]
Message-ID: <20140321105906.GA1725@netbook.cypherspace.org> (raw)
In-Reply-To: <lgh438$tnn$1@ger.gmane.org>
Maybe its time to explore raw ECDSA signed message based certs.
btw I dont think its quite 4kB. eg bitpay's looks to be about 1.5kB in der
format. And they contain a 2048-bit RSA server key, and 2048-bit RSA
signatures (256byte each right there = 512bytes). And even 2048 is weaker
than 256-bit ECDSA.
Adam
On Fri, Mar 21, 2014 at 11:25:59AM +0100, Andreas Schildbach wrote:
>On 03/20/2014 01:12 PM, Adam Back wrote:
>
>> Whats a sensible limit on practical/convenient QR code size?
>
>Technically 3 KB. In my experience codes above 1.5 KB become impossible
>to scan (ZXing scanner, 3 years ago). You will want to stay below 500
>bytes for convenient scanning. That said, I'm convinced there is a lot
>of room for scanning improvements.
>
>> How much of the payment protocol message size comes from use of x509?
>
>As said in the OP, a minimal PR uses 50 bytes. X.509 seems to put about
>4000 bytes on top of that.
>
>As you can see, we have quite some room for improvements to PR payload
>(PaymentDetails). X.509 certification will probably not be possible via
>QR, at least not until specialized CA's will issue space-efficient certs
>(using ECDSA?).
next prev parent reply other threads:[~2014-03-21 10:59 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
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 [this message]
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
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