Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1WDG8E-0001Ew-FG for bitcoin-development@lists.sourceforge.net; Tue, 11 Feb 2014 16:24:22 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.214.179 as permitted sender) client-ip=209.85.214.179; envelope-from=mh.in.england@gmail.com; helo=mail-ob0-f179.google.com; Received: from mail-ob0-f179.google.com ([209.85.214.179]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1WDG8C-0000U5-J5 for bitcoin-development@lists.sourceforge.net; Tue, 11 Feb 2014 16:24:22 +0000 Received: by mail-ob0-f179.google.com with SMTP id wo20so8993638obc.24 for ; Tue, 11 Feb 2014 08:24:15 -0800 (PST) MIME-Version: 1.0 X-Received: by 10.60.134.166 with SMTP id pl6mr10764455oeb.16.1392135855095; Tue, 11 Feb 2014 08:24:15 -0800 (PST) Sender: mh.in.england@gmail.com Received: by 10.76.71.231 with HTTP; Tue, 11 Feb 2014 08:24:12 -0800 (PST) Received: by 10.76.71.231 with HTTP; Tue, 11 Feb 2014 08:24:12 -0800 (PST) In-Reply-To: <0CC0BE1D-1DAA-4994-B034-EB7712F845CF@kill-bill.org> References: <0CC0BE1D-1DAA-4994-B034-EB7712F845CF@kill-bill.org> Date: Tue, 11 Feb 2014 17:24:12 +0100 X-Google-Sender-Auth: xD1ZqHN1o1pOgFrLTXhZf3XnvNE Message-ID: From: Mike Hearn To: Stephane Brossier Content-Type: multipart/alternative; boundary=047d7b41cc3e1f443004f223e31b X-Spam-Score: -0.5 (/) 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 (mh.in.england[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message 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: 1WDG8C-0000U5-J5 Cc: Bitcoin Dev , Pierre-Alexandre Meyer Subject: Re: [Bitcoin-development] Extension for BIP-0070 to support recurring 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: Tue, 11 Feb 2014 16:24:22 -0000 --047d7b41cc3e1f443004f223e31b Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hey guys, I'm on vacation now so won't be able to take a look until I'm back in a couple of weeks but the approach sounds reasonable based on your description. On 8 Feb 2014 08:28, "Stephane Brossier" wrote: > Mike and all, > > Pierre and I just committed a prototype implementation of the recurring > payment protocol using bitcoinj. You can find the diff on our fork: > > https://github.com/killbill/bitcoinj/commit/40c657c4191498f12539c60316116= aa68af368a7 > > We did not write the server (merchant side), but wanted to have some > feedback before going deeper (merchant implementation and tests). We did > our best to build it on top of the existing BIP-0070 protocol-- only a fe= w > additions in the messages, but no new calls and no new uri scheme. We > created a new package 'recurring' where most of the new code lives. > > At a high level: > > 1. Creation of the subscription: > > The initial handshake for creating the subscription is exactly similar to > the one for the payment protocol (PaymentRequest is used to provide the > contract) > > 2. Wallet can decide to poll the merchants for its active subscriptions. > > Here the flow is exactly similar to the payment protocol but the wallet > receives a callback to verify the payment matches the contract and should > go through. > > Please give us some feedback whenever you have the chance. In the meantim= e > we will start implementing the merchant side and test the code. > > Cheers! > > > > On Jan 31, 2014, at 10:13 AM, Mike Hearn wrote: > > That looks OK at a very high level. Things you probably want to think > about: > > - How to trigger it off the existing payment protocol (no new top > level messages or mime types or uri extensions please) > - Data structures to define the payment schedule > - Do you allow pre-submission of time locked transactions or not? > > I think as you prototype these things will become clearer. You could try > prototyping either in Bitcoin Core (C++) or bitcoinj (java, look at the > PaymentSession class). > > > > On Wed, Jan 29, 2014 at 3:47 AM, Stephane Brossier > wrote: > >> >> >> >> >> >> >> >> >> >> >> >> >> >> *From what I have seen so far, there seems to be an agreement that this >> is a nice feature to add. We are pretty new to that community and so we >> don't know exactly what the process is, and in particular how we reach >> consensus via email. I am certainly open to follow 'the way' if there is >> one, but one solution would be to follow Mike's suggestion on providing = a >> (prototype) implementation first and then defining/refining the BIP. Odi= nn >> also suggested a possible retribution for our time through crowd-sourcin= g >> which I am interested to pursue if that makes sense. We have quite some >> experience on the subscription side of things and while we are growing o= ur >> knowledge on the Bitcoin technology (and ecosystem at large) we would >> benefit from: * some feedbacks on the high level proposal * additional >> requirements we might have missed So, below is a high level description = of >> what we have in mind. If this sounds reasonable, we could start working = on >> an implementation. I. Abstract --------------- This describes a protocol= to >> enable recurring payments in bitcoins and can be seen as an extension of >> BIP-0070. The main goal here is to have the customer subscribe to a serv= ice >> of some kind (that is, agreeing on the terms of that subscription >> contract), and then have the wallet make recurring payments without any >> intervention from the customer as long as the payments match what the >> customer agreed on paying. An example of such service would be an online >> streaming website, to which a user pays a fixed recurring monthly fee to >> access videos (a.k.a. resources). Note that there is also usage based >> billing: for example, the user may need to purchase additional access fo= r >> premium videos (overage charges). This type of billing is more complicat= ed >> and there are many variations to it used in the industry (pre-paid, =E2= =80=A6). For >> the sake of discussion, we=E2=80=99ll focus on fixed recurring payments = only, but >> we will keep usage in mind to make sure the protocol will be able to >> support it as well. II. Motivation ------------------ Subscription based >> services have been growing in the past few years and so the intent it to >> make it possible for customers to pay in bitcoins. Bitcoin=E2=80=99s pus= h model >> presents new advantages for the customer compared to traditional payment >> methods: the user has control over the subscription (for example, there = is >> no need to call the merchant to explicitly cancel the credit card >> payments). It also opens the door to subscription management tools in >> wallets (e.g. Hive apps), which would give user an overview of what they >> are paying each month. III. Flow of >> Operations----------------------------------------* >> >> >> >> >> * Creation of the subscription: - - - - - - - - - - - - - - - - - - - - = - >> - 1. The customer clicks 'subscribe' -> A message is sent to the merchan= t. >> 2. The merchant sends back a message to the wallet with the details of t= he >> subscription such as the amount to be paid. In reality, there will be mo= re >> information but for the purpose of the prototype implementation this is >> sufficient. 3. The wallet prompts the customer for authorization. 4. The >> customer authorizes (or denies) it. 5. The wallet sends the confirmation= to >> the merchant. 6. The merchant confirms the subscription was created. >> Ongoing payments: * >> >> *- - - - - - - - - - - - - - - - * >> >> >> >> >> >> >> * From that time on and since Bitcoin is a 'push' model, the wallet is >> responsible to poll the merchant for due payments associated with that >> subscription. Note that the merchant could specify hints to the wallet o= n >> when to poll (specific dates) or not during the registration of the >> subscription. Note that we can't simply have the wallet push X bitcoins >> every month: the user account on the merchant side may have gotten credi= ts, >> invoice adjustments, etc. since the last invoice, so the amount to pay f= or >> a given billing period may be lower than the regular amount. It could ev= en >> be zero if the user decides to make a one-time payment to the merchant >> directly using a different wallet. Hence, the wallet needs to get the >> latest invoice balance to make sure how much it should pay. This also op= ens >> the door for the support of overage charges. Quick note on the >> implementation on the merchant side: an entitlement system is a piece of >> logic on the merchant side which grants the user access to certain >> resources depending on the account status (unpaid invoices, etc.). This >> goes often hand in hand with a dunning system, which progressively >> restricts access as the user's account is more and more overdue. Since >> wallets can be offline for an extended period of time, payments may be >> missed and lead to an overdue state (e.g. extra fees, service degraded).= It >> is the responsibility of the customer to ensure the wallet is up often >> enough for payments to happen. In that recurring phase where the wallet >> polls the merchant, the wallet is responsible to check that payments mat= ch >> the subscription contract; that is, the amount, frequency of payments, = =E2=80=A6 >> match what the customer agreed on. If so, the payment is made without >> asking for explicit approval from customer, and the flow is similar to >> BIP-0070: The message is sent to the merchant, and in parallel, a >> transaction is sent to the btcnet. The merchant sends an ACK to the wall= et >> and of course checks the states of the transactions on the btcnet to mar= k >> that payment as successful. Subscription change (optional): * >> >> *- - - - - - - - - - - - - - - - - - - - - - - - * >> >> >> * Optionally we could implement a change in the ongoing subscription to >> address the upgrade/downgrade scenarios. Of course, we could also simply >> support a cancellation followed by a creation of a new subscription, but >> having that as a one atomic message is probably better. The steps are ve= ry >> similar to the initial registration. 1. The customer clicks 'upgrade', >> 'downgrade', =E2=80=A6 -> A msg is sent to the merchant. 2. The merchant= sends back >> a msg to the wallet with the detail of the NEW subscription. 3. The wall= et >> prompts the customer for authorization. 4. The customer authorizes (or >> denies) it. 5. The wallet sends the confirmation to the merchant. 6. The >> merchant confirms the change in the subscription. Cancellation of the >> subscription: * >> >> *- - - - - - - - - - - - - - - - - - - - - - - - - * >> >> >> >> * The cancellation is initiated from the customer: 1. The customer click= s >> 'cancel' -> The wallet is informed that it should not accept any new >> payment associated to that subscription. 2. The wallet sends a message t= o >> the merchant to inform about the cancellation. 3. The merchant confirms = the >> subscription was cancelled. * >> > > > --047d7b41cc3e1f443004f223e31b Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

Hey guys,

I'm on vacation now so won't be able to take a look = until I'm back in a couple of weeks but the approach sounds reasonable = based on your description.

On 8 Feb 2014 08:28, "Stephane Brossier&quo= t; <stephane@kill-bill.org= > wrote:
Mike and all,

Pierre= and I just committed a prototype implementation of the recurring payment p= rotocol using bitcoinj. You can find the diff on our fork:=C2=A0

We did not write the server (merchant side), but wanted= to have some feedback before going deeper (merchant implementation and tes= ts). We did our best to build it on top of the existing BIP-0070 protocol--= only a few additions in the messages, but no new calls and no new uri sche= me. We created a new package 'recurring' where most of the new code= lives.

At a high level:

1. Creation o= f the subscription:

The initial handshake for crea= ting the subscription is exactly similar to the one for the payment protoco= l (PaymentRequest is used to provide the contract)

2. Wallet can decide to poll the merchants for its acti= ve subscriptions.

Here the flow is exactly similar= to the payment protocol but the wallet receives a callback to verify the p= ayment matches the contract and should go through.

Please give us some feedback whenever you have the chan= ce. In the meantime we will start implementing the merchant side and test t= he code.

Cheers!



On Jan 31, 2014, at 10:13 AM, Mike Hearn <mike@plan99.net> wro= te:

That looks OK at a = very high level. Things you probably want to think about:
  • How to trigger it off the existing payment protocol (no new top lev= el messages or mime types or uri extensions please)
  • Data structures to define the payment schedule
  • Do you allow pre= -submission of time locked transactions or not?
I think as yo= u prototype these things will become clearer. =C2=A0You could try prototypi= ng either in Bitcoin Core (C++) or bitcoinj (java, look at the PaymentSessi= on class).



On Wed, Jan 29, 2014 at 3:47 AM, Stephane Brossier <st= ephane@kill-bill.org> wrote:
From what I have seen so far, there seems to be an a= greement that this is a nice feature to add.
We are pretty new to that community a= nd so we don't know exactly what the process is, and in particular how = we reach consensus via email. I am certainly open to follow 'the way= 9; if there is one, but one solution would be to follow Mike's suggesti= on on providing a (prototype) implementation first and then defining/refini= ng the BIP. Odinn also suggested a possible retribution for our time throug= h crowd-sourcing which I am interested to pursue if that makes sense.


We have quite some experience on the = subscription side of things and while we are growing our knowledge on the B= itcoin technology (and ecosystem at large) we would benefit from:
* some feedbacks on the high level proposal
* additional requirements we might have missed<= /span>


I. Abstract
---------------

This describes a protocol to enable r= ecurring payments in bitcoins and can be seen as an extension of BIP-0070. = The main goal here is to have the customer subscribe to a service of some k= ind (that is, agreeing on the terms of that subscription contract), and the= n have the wallet make recurring payments without any intervention from the= customer as long as the payments match what the customer agreed on paying.=

II. Motivation
------------------

Subscription based services have been= growing in the past few years and so the intent it to make it possible for= customers to pay in bitcoins.


III. Flow of Operations
--------------------= --------------------


Creation of the subscription:
- - - - - - - - - - - - - - - - - - - - - -

1. The customer clicks 'subscribe= ' -> A message is sent to the merchant.
2. The merchant sends back a message = to the wallet with the details of the subscription such as the amount to be= paid. In reality, there will be more information but for the purpose of th= e prototype implementation this is sufficient.
3. The wallet prompts the customer for authoriz= ation.
4. The customer authorizes (or denies) it.
5. The wallet sends the confirmation to the mer= chant.
6. The merchant confirms the subscription was c= reated.

Ongoing payments:=
- - - - - - - - - - - - - - - -

From that time on and since Bitcoin i= s a 'push' model, the wallet is responsible to poll the merchant fo= r due payments associated with that subscription. Note that the merchant co= uld specify hints to the wallet on when to poll (specific dates) or not dur= ing the registration of the subscription.


Quick note on the implementation on t= he merchant side: an entitlement system is a piece of logic on the merchant= side which grants the user access to certain resources depending on the ac= count status (unpaid invoices, etc.). This goes often hand in hand with a d= unning system, which progressively restricts access as the user's accou= nt is more and more overdue. Since wallets can be offline for an extended p= eriod of time, payments may be missed and lead to an overdue state (e.g. ex= tra fees, service degraded). It is the responsibility of the customer to en= sure the wallet is up often enough for payments to happen.


In that recurring phase where the wal= let polls the merchant, the wallet is responsible to check that payments ma= tch the subscription contract; that is, the amount, frequency of payments, = =E2=80=A6 match what the customer agreed on. If so, the payment is made wit= hout asking for explicit approval from customer, and the flow is similar to= BIP-0070: The message is sent to the merchant, and in parallel, a transact= ion is sent to the btcnet. The merchant sends an ACK to the wallet and of c= ourse checks the states of the transactions on the btcnet to mark that paym= ent as successful.

Subscription chan= ge (optional):
- - - - - - - - - - - - - - - - - - - - - - - -

Optionally we could implement a chang= e in the ongoing subscription to address the upgrade/downgrade scenarios. O= f course, we could also simply support a cancellation followed by a creatio= n of a new subscription, but having that as a one atomic message is probabl= y better. The steps are very similar to the initial registration.
2. The merchant sends back a msg to the wallet = with the detail of the NEW subscription.
3. The wallet prompts the customer for authoriz= ation.
4. The customer authorizes (or denies) it.
5. The wallet sends the confirmation to the mer= chant.
6. The merchant confirms the change in the subs= cription.

Cancellation of t= he subscription:
- - - - - - - - - - - - - - - - - - - - - - - - -

The cancellation is initiated from th= e customer:

1. The customer clicks 'cancel= 9; -> The wallet is informed that it =C2=A0should not accept any new pay= ment associated to that subscription.
2. The wallet sends a message to the merchant t= o inform about the cancellation.
3. The merchant confirms the subscription was c= ancelled.




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