Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1WN1pr-000700-Fe for bitcoin-development@lists.sourceforge.net; Mon, 10 Mar 2014 15:09:47 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.220.176 as permitted sender) client-ip=209.85.220.176; envelope-from=alexy.kot.all@gmail.com; helo=mail-vc0-f176.google.com; Received: from mail-vc0-f176.google.com ([209.85.220.176]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1WN1pp-0002ms-VA for bitcoin-development@lists.sourceforge.net; Mon, 10 Mar 2014 15:09:47 +0000 Received: by mail-vc0-f176.google.com with SMTP id lc6so6501541vcb.7 for ; Mon, 10 Mar 2014 08:09:40 -0700 (PDT) X-Received: by 10.220.95.139 with SMTP id d11mr5106648vcn.21.1394464180415; Mon, 10 Mar 2014 08:09:40 -0700 (PDT) MIME-Version: 1.0 Sender: alexy.kot.all@gmail.com Received: by 10.59.0.38 with HTTP; Mon, 10 Mar 2014 08:09:00 -0700 (PDT) In-Reply-To: <20140308085242.GA5727@odo.localdomain> References: <20140308085242.GA5727@odo.localdomain> From: Alex Kotenko Date: Mon, 10 Mar 2014 15:09:00 +0000 X-Google-Sender-Auth: ztkQznb82tNN-T7S7NZeVYZrzQ4 Message-ID: To: Jan Vornberger Content-Type: multipart/alternative; boundary=001a11c2ae7620350e04f441fe5c X-Spam-Score: -0.6 (/) 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 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (alexy.kot.all[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature X-Headers-End: 1WN1pp-0002ms-VA Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Instant / contactless 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: Mon, 10 Mar 2014 15:09:47 -0000 --001a11c2ae7620350e04f441fe5c Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 2014-03-08 8:52 GMT+00:00 Jan Vornberger : =E2=80=8B=E2=80=8B > On Thu, Mar 06, 2014 at 02:39:52PM +0000, Alex Kotenko wrote: > > Not sure if you've seen it, but here is how we do NFC right now > > http://www.youtube.com/watch?v=3DDGOMIG9JUY8 with XBTerminal. > > Very interesting, thanks for sharing! Are the two devices on the same > wifi network in the demo? In my experience transaction propagation > through the Bitcoin network takes a couple of seconds longer on average, > so I'm surprised it's that fast here. > No, devices on this video are not on the same network, and even if they would - I cannot control what =E2=80=8B=E2=80=8Bremote hosts my phone would= connect to, so transaction may anyway travel around the globe before coming to the POS even if they would be on one LAN. As for transaction times - I'd say it varies. =E2=80=8BFrom my extensive te= sting most of transactions usually come through within 2-5 seconds, but roughly one in ten transactions may take more time, sometimes much more time. You probably share this view, but I just wanted to repeat, that from my > experiments, I think that sending the transaction only over the Bitcoin > network should be a rarely-used fallback. It usually takes a little > longer than you would like for a POS solution and every so often you > don't get the transaction at all until the next block. And then what do > you do? Maybe you would need to ask the customer to pay again, to get > things done now, and put the previous transaction in some kind of refund > mode, where - when you finally get it - you send it back somewhere. But > it's really a problematic corner case - but yet it will happen > occasionally with network-only propagation. > =E2=80=8BYes, =E2=80=8BI'm certain about that we need to switch to BIP70 as= ap. As I said earlier - support among the wallets is the biggest problem here really. Only Andreas' Wallet supports it right now AFAIK, and even in there it's only as "LABS feature", so will be turned off for most of users. In the context of this discussion, I would also like to share a video of > a prototype system: > > https://www.youtube.com/watch?v=3DmguRpvf3aMc > > Here shown is the (currently no longer working) Bridgewalker client, but > it is also fully compatible with Andreas' wallet. The client picks up > the payment details via NFC (as a Bitcoin URI - could and should be > updated to use payment protocol) and transmits a copy of the transaction > via Bluetooth (using the simple convention first implemented by > Andreas). One optimization I did in the Bridgewalker client is, that it > already opens the Bluetooth connection when presenting the user with the > confirmation dialog. This results in a little additional speed-up, as > the connection is already "warmed up", when the user confirms. All code > of this prototype is open source, as is the Bridgewalker client. > Yes, I've seen this demonstration, I think it was on reddit about two month=E2=80=8B=E2=80=8B ago. Looks interesting, but by that time most of my= client software was already done, so I couldn't really use this. > >From my testing, I can say that NFC for getting the payment details + > Bluetooth for transmitting the transaction back works well. I'm a bit > skeptical about using NFC also for the back-channel, but maybe for cases > where there is no additional user confirmation it could work. =E2=80=8BNFC =E2=80=8Bas =E2=80=8B back channel =E2=80=8Bdefinitely =E2=80=8B will not work =E2=80=8B. Mike proposed something =E2=80=8Blike a threshold to define mini= mal amount available for spending without confirmation, but I don't see this thing becoming widely used any time soon, and before that we will need to have "confirm" button tap. One problem with Bluetooth I see is, that it seems to be mostly turned > off by users and many seem to perceive it as "insecure", to have it > active, as a result of earlier Bluetooth hacks. So I'm not sure if that > will turn out to be a problem for usability when rolled-out in practice. > Yes, this is a problem, I think bluetooth is offline on many devices, and keeping it on all the time will harm security (if not real security, then at least perceived by users) and also harm battery life, which will be seen as huge problem by the users. =E2=80=8BWould be great to be =E2=80=8Bable to control BT state automatical= ly from within the wallet app with user permission given once on installation time, but not sure if it's possible in Android. > > -------------------------------------------------------------------------= ----- > Subversion Kills Productivity. Get off Subversion & Make the Move to > Perforce. > With Perforce, you get hassle-free workflows. Merge that actually works. > Faster operations. Version large binaries. Built-in WAN optimization and > the > freedom to use Git, Perforce or both. Make the move to Perforce. > > http://pubads.g.doubleclick.net/gampad/clk?id=3D122218951&iu=3D/4140/ostg= .clktrk > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > --001a11c2ae7620350e04f441fe5c Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
2014-03-08 8:52 GMT+00:00 Jan Vornberger <jan@uos.de>:
=E2=80=8B=E2=80=8B
On Thu, Mar 06, 2014 at 02:39:52PM +0000, Alex Kotenko wrote:
> Not sure if you've seen it, but here is how we do NFC right now > http://www.youtube.com/watch?v=3DDGOMIG9JUY8 with XBTerminal.

Very interesting, thanks for sharing! Are the two devices on the same
wifi network in the demo? In my experience transaction propagation
through the Bitcoin network takes a couple of seconds longer on average, so I'm surprised it's that fast here.
No, devices on this video are not on the same network, and eve= n if they would - I cannot control what =E2=80=8B=E2=80=8Bremote hosts my p= hone would connect to, so transaction may anyway travel around the globe be= fore coming to the POS even if they would be on one LAN.
As for transaction times - I'd say it varies.= =E2=80=8BFrom my extensive testing most of transactions usually come throu= gh within 2-5 seconds, but roughly one in ten transactions may take more ti= me, sometimes much more time. =C2=A0


You probably share this view, but I just wanted to repeat, that from my
experiments, I think that sending the transaction only over the Bitcoin
network should be a rarely-used fallback. It usually takes a little
longer than you would like for a POS solution and every so often you
don't get the transaction at all until the next block. And then what do=
you do? Maybe you would need to ask the customer to pay again, to get
things done now, and put the previous transaction in some kind of refund mode, where - when you finally get it - you send it back somewhere. But
it's really a problematic corner case - but yet it will happen
occasionally with network-only propagation.
=E2=80=8BYes, =E2=80=8BI'm certain about that we need t= o switch to BIP70 asap. As I said earlier - support among the wallets is th= e biggest problem here really. Only Andreas' Wallet supports it right n= ow AFAIK, and even in there it's only as "LABS feature", so w= ill be turned off for most of users.


In the context of this discussion, I would also like to share a video of a prototype system:

=C2=A0 https://www.youtube.com/watch?v=3DmguRpvf3aMc

Here shown is the (currently no longer working) Bridgewalker client, but it is also fully compatible with Andreas' wallet. The client picks up the payment details via NFC (as a Bitcoin URI - could and should be
updated to use payment protocol) and transmits a copy of the transaction via Bluetooth (using the simple convention first implemented by
Andreas). One optimization I did in the Bridgewalker client is, that it
already opens the Bluetooth connection when presenting the user with the confirmation dialog. This results in a little additional speed-up, as
the connection is already "warmed up", when the user confirms. Al= l code
of this prototype is open source, as is the Bridgewalker client.
Yes, I've seen this demonstration, I th= ink it was on reddit about two month=E2=80=8B=E2=80=8B ago. Looks interesti= ng, but by that time most of my client software was already done, so I coul= dn't really use this.

=C2=A0
>From my testing, I can say that NFC for getting the payment details + Bluetooth for transmitting the transaction back works well. I'm a bit skeptical about using NFC also for the back-channel, but maybe for cases where there is no additional user confirmation it could work.
<= div>=E2=80=8BNFC
=E2=80=8Bas =E2=80=8B
back channel
=E2=80= =8Bdefinitely =E2=80=8B
will not work
=E2=80=8B. Mike pro= posed something =E2=80=8Blike a=C2=A0threshold=C2=A0to define minimal amoun= t available for spending without confirmation, but I don't see this thi= ng becoming widely used any time soon, and before that we will need to have= "confirm" button tap.


One problem with Bluetooth I see is, that it seems to be mostly turned
off by users and many seem to perceive it as "insecure", to have = it
active, as a result of earlier Bluetooth hacks. So I'm not sure if that=
will turn out to be a problem for usability when rolled-out in practice.
Yes, this is a problem, I thin= k bluetooth is offline on many devices, and keeping it on all the time will= harm security (if not real security, then at least perceived by users) and= also harm battery life, which will be seen as huge problem by the users.
=E2=80=8BWould be great to be =E2=80=8Bable to co= ntrol BT state automatically from within the wallet app with user permissio= n given once on installation time, but not sure if it's possible in And= roid.=C2=A0

=C2=A0
---------------------------------------------------------------------------= ---
Subversion Kills Productivity. Get off Subversion & Make the Move to Pe= rforce.
With Perforce, you get hassle-free workflows. Merge that actually works. Faster operations. Version large binaries. =C2=A0Built-in WAN optimization = and the
freedom to use Git, Perforce or both. Make the move to Perforce.
http://pubads.g.doubleclick.net/gam= pad/clk?id=3D122218951&iu=3D/4140/ostg.clktrk
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Bitcoin-development mailing list
Bitcoin-development@lists.sourceforge.net
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