Re: The case for registration as a technical specification

On 13 July 2015 at 11:31, Brett Wilson <brettw@google.com> wrote:

> On Mon, Jul 13, 2015 at 4:25 AM, L. David Baron <dbaron@dbaron.org> wrote:
>
>> On Thursday 2015-07-09 17:34 +0200, Adrian Hope-Bailie wrote:
>> > Hi David,
>> >
>> > I agree and I think that the discussion re the charter to date suggests
>> > others do too.
>> >
>> > One thing I wanted to clarify is the role of the browser/UA in the
>> > currently proposed flow. This is my understanding and I'm happy for
>> anyone
>> > to chime in with a different perspective.
>> >
>> > As it stands, the proposal is to create a standard WebIDL API that
>> allows
>> > websites to initiate a payment by passing a standardised message to the
>> > browser and for that API to respond with a standardised message back to
>> the
>> > website. This process will be repeated for a completion request and
>> > response.
>> >
>> > When the browser receives this message it should do one of two things:
>> >
>> >    1. Pass it directly to a configured wallet, unmodified
>> >    2. Decline the API request as there is no wallet configured
>> >
>> > i.e. I'd like the browser's participation in the flow to simply be as a
>> > proxy of messages between the website and the user's wallet.
>> >
>> > We are proposing that there may be 3 types of wallet:
>> >
>> > 1. Cloud-based. In which case the browser passes the requests message
>> via
>> > HTTP (a REST API of sorts) to the wallet service and get's back a
>> response.
>> > (Details of how this would work, including hosting of the wallet UI in a
>> > frame or new window will be left to the WG to decide).
>> >
>> > 2. Native. Meaning the user installed some wallet software (or app in
>> the
>> > case of a smartphone) and there is a mechanism for the browser to
>> > communicate with that native wallet service. It will be for the browser
>> > vendors to propose how this is done or if it should be standardised.
>> > Perhaps it will be simplest to say that native wallets must host an HTTP
>> > endpoint service so that the interface matches cloud-based wallets, or
>> > maybe they will need to take the form of browser extensions.
>> >
>> > 3. Built-in to the browser or OS. In this case I think it's outside the
>> W3C
>> > WG's scope to define the delivery mechanism for messages between the UA
>> and
>> > the wallet service but the standard could still mandate that the
>> messages
>> > passed between the UA and wallet must follow the standard format.
>>
>> Saying that there can be three different types of wallet and not
>> defining how they really work seems dangerous to me.  It makes the
>> wallet concept like a black box, which means an essential part of
>> the system is not defined by the standard, and thus unlikely to be
>> sufficiently open.
>>
>
> Need a "wallet" by anything more than a list of payment instruments?
>

Yes.

As I said to David, wallets need to know how to use a payment instrument
according to the rules of the scheme for which the instrument is issued.


> I would expect the system to have a list of payment instruments provided
> via a system-specific API.
>

Why system specific? The standard is aiming to define a set of standard
messages that the wallet must process and a set of standard responses the
wallet must return. The actual delivery mechanism may differ but the
messages and flow will be standardized.



> Likewise, the browser might maintain some web payment instruments in its
> own database that it merges with system instruments to display to the user.
>

Why would the browser display the list of instruments to the user? The
intention is for the browser to simply be a proxy of messages between the
wallet and the calling application.

If the wallet is built into the browser then it may be the component that
prompts the user but if it is not then I'd expect the wallet service itself
to display this UI.

The "merging" you describe is what we have called an aggregation service
but I'd recommend that the browser doesn't attempt to do this but rather
allow user's to configure the browser with their preferred wallet.

Browser can take on this role if the user hasn't explicitly configured
another wallet and I'd recommend that the standard makes it mandatory to
allow users to pick a wallet other than the browser.


> How these are stored or retrieved in any particular situation isn't
> something that can or should be standardized.
>
>
Correct. Wallets are free to store and retrieve instruments and the
meta-data they require as they wish. Some schemes will define how this must
be done if the data is sensitive.

Alternatively the mechanism that is used may be a competitive
differentiator for a wallet. Example: a wallet that supports Bitcoin may
support a sophisticated multi-sig or hardware-based mechanism for executing
transaction.


>
>
>
I think the term "wallet" is confusing since it gives the impression that
> there's a thing people can point to that has specific properties. I would
> personally prefer if it was just replaced with "list of payment
> instruments" every time it appears.
>
>
The wallet is a thing that people WILL point their browser to that does
have specific properties. The most important will be that it supports the
APIs we are defining. It is NOT just a list of instruments. It maintains a
list of instruments that the user has registered but also has knowledge
about how to use those instruments.


> Brett
>