Opentabs PROTOCOL
==================

Opentabs follows the Web Credits Draft spec proposed at the W3C
Web Payments group.

http://webcredits.org/


User
====

Each user is a URI.  URIs link to other URIs using linked data
principles, including Webfinger discovery, and web Intents.


Authentication
==============

Opentabs does not specify the authentication method, but so far WebID,
Oauth2 (Gmail/Yahoo) and Facebook connect are supported.  We are keen
to support BrowserID, more can be added on request.


Linking a User to IOUs
=======================

This is to be defined so that a user can have one or more spaces for
storing IOUs.

<#me> opentabs:IOUs <target>

Currently for the alpha test we are storing <target> in a well known
location on the MIT data.fm server.  As things scale to beta and full
production distributing the storage will be a key consideration.  It
is a project goal to port the system to be usable with the unhosted
infrastructure.



IOU
===

We use the following template based on the payswarm Transfer type.

source      (aka payer)
destination (aka payee)
amount      (aka quantity)
currency
comment     (aka note / description)
created     (aka createddate)


Each IOU is a self describing data structure, general with global
namespaces to enable a scale free system.

In JSON:

{
   "@id": "#1234567890",
   "http://payswarm.com/vocabs/commerce#source": {
       "@id": "http://melvincarvalho.com#me"
   },
   "http://payswarm.com/vocabs/commerce#destination": {
       "@id": "http://webr3.org/nathan#me"
   },
   "http://payswarm.com/vocabs/commerce#amount": "5",
   "http://payswarm.com/vocabs/commerce#currency": "EUR",
   "http://www.w3.org/2000/01/rdf-schema#comment": "Just a test IOU",
   "http://purl.org/dc/terms/created": "2011-12-20T15:42:41.030Z",
   "http://www.w3.org/1999/02/22-rdf-syntax-ns#type": {
       "@id": "http://payswarm.com/vocabs/commerce#Transfer"
   }
}

In Turtle

<#1234567890>
  <http://payswarm.com/vocabs/commerce#amount> "5";
  <http://payswarm.com/vocabs/commerce#currency> "EUR";
  <http://payswarm.com/vocabs/commerce#destination>
<http://webr3.org/nathan#me>;
  <http://payswarm.com/vocabs/commerce#source> <http://melvincarvalho.com#me>;
  <http://purl.org/dc/terms/created> "2011-12-20T15:42:41.030Z";
  <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://payswarm.com/vocabs/commerce#Transfer>;
  <http://www.w3.org/2000/01/rdf-schema#comment> "Just a test IOU".

Experiment in the JSON playground

http://is.gd/Km1iOA

The abstract nature of this data structure makes it both extensible,
linkable and transformable to other formats.


Aggregation
===========

It is the job of the front end to aggregate, net and display IOUs to the user.


Friends
=======

For convenience we currently try and pull in a list of friends to
populate the payee dropdown.  New recipients can be added and are
cached.


Workflow
========

Currently we have only the most basic workflow for adding an IOU.
Without doubt there will be more added, but our aim is to decouple the
data layer with the application logic so that arbitrarily many
workflows are possible working with the same data stores.


A Basic Example
================

Alice wants to give bob 5 euros

Alice authenticates
The app discovers where alices wallet is
Alice takes 5 euro out of her wallet (by adding the JSON)
Alice gives 5 euros to bob (by giving him the JSON) 
Bob puts 5 euros in his wallet using a POST the JSON


Encryption
==========

Currently we have not included encryption and signature for the alpha,
but it is on the roadmap.