OpenID Attribute Exchange is an extension for OpenID service which allows the transfer of various user related details/information/attributes between the relying party and the identity provider. There are two primary operations that can be done using the Attribute Exchange:
a) Fetch/retrieve some required attribute about the user from the identity provider.
b) Store some additional attribute about the user on his identity provider.
The OpenID Attribute Exchange service extension provides a mechanism for moving identity information between sites with the following information model:
An attribute associated with a Subject Identifier, i.e, an URI.
An attribute having a type identifier( another URI, which is used for referring to property values) and a value(any kind of data)
The Relying Party module part will allow for discovery, fetch request message and store request message using the standard specifications as described in
Also the Identity Provider part of the module will allow for fetch response and store response in the apt formats as detailes by the standard specifications.
How does this module differ from openid_sreg module?
Simple Registration is designed to pass eight commonly requested pieces of information when an End User goes to register a new account with a web service.
No. of attributes in AX attributes specs drafts is much more.
S.Reg allows you only to fetch data from the OpenID OP.
Using AX, the RP can store the data with OP as well with due permission from the user.
Drupal wiki link::
Google SoC Abstract::