From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1WQw2t-00073f-5f for bitcoin-development@lists.sourceforge.net; Fri, 21 Mar 2014 09:47:23 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of m.gmane.org designates 80.91.229.3 as permitted sender) client-ip=80.91.229.3; envelope-from=gcbd-bitcoin-development@m.gmane.org; helo=plane.gmane.org; Received: from plane.gmane.org ([80.91.229.3]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1WQw2r-00063t-C7 for bitcoin-development@lists.sourceforge.net; Fri, 21 Mar 2014 09:47:23 +0000 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1WQw2k-0000un-DM for bitcoin-development@lists.sourceforge.net; Fri, 21 Mar 2014 10:47:14 +0100 Received: from e179064016.adsl.alicedsl.de ([85.179.64.16]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 21 Mar 2014 10:47:14 +0100 Received: from andreas by e179064016.adsl.alicedsl.de with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 21 Mar 2014 10:47:14 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: bitcoin-development@lists.sourceforge.net From: Andreas Schildbach Date: Fri, 21 Mar 2014 10:47:03 +0100 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: e179064016.adsl.alicedsl.de User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 In-Reply-To: X-Enigmail-Version: 1.5.2 X-Spam-Score: -0.4 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [80.91.229.3 listed in list.dnswl.org] -0.0 SPF_HELO_PASS SPF: HELO matches SPF record 1.1 DKIM_ADSP_ALL No valid author signature, domain signs all mail -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -0.0 SPF_PASS SPF: sender matches SPF record X-Headers-End: 1WQw2r-00063t-C7 Subject: Re: [Bitcoin-development] Payment Protocol for Face-to-face Payments X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 21 Mar 2014 09:47:23 -0000 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:/​ > " 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.