Method and system for discovering an identity provider

1. A method comprising:

registering an external service provider with a discovery service and storing a token for the external service provider in the discovery service, said discovery service associated with a primary service provider;

forming, at a user device, a common domain cookie comprising a list of identity location identifiers;

receiving a request for restricted content at an external service provider from the user device, comprising the common domain cookie, said request for restricted content comprising a location identifier for the restricted content;

forming, at the external service provider, a redirection request based on the request for restricted content, an external service provider identifier, and a return response location identifier;

communicating the redirection request from the external service provider to the discovery service with the common domain cookie;

determining, at the discovery service, whether the redirection request originates from the external service provider that is registered based on the token;

when the redirection request originates from the external service provider that is registered, parsing the redirection request at the discovery service to obtain a previously used identity provider location identifier from the list of identity location identifiers within the common domain cookie and the external service provider identifier;

generating a response at the discovery service with the previously used identity provider location identifier;

communicating the response to the external service provider based on the return response location identifier wherein the response comprises the identity provider location identifier;

generating an authentication request at the external service provider with the previously used identity provider location identifier;

communicating the authentication request to the identity provider based on the previously used identity provider location identifier;

authenticating the user device at the identity provider; and

allowing access to the restricted content based on authenticating.

2. A method as recited in claim 1 wherein receiving the request comprises receiving the request for restricted content at the external service provider from a mobile user device.

3. A method as recited in claim 1 wherein parsing the redirection request at the discovery service to obtain the identity provider location identifier comprises parsing the redirection request at the discovery service to obtain a previously used identity provider location identifier.

4. A method as recited in claim 1 wherein the previously used identity provider location comprises a last used identity provider identifier.

5. A method as recited in claim 1 further comprising forming a common domain cookie that includes a last used identity provider identifier at a user device.

6. A method as recited in claim 1 further comprising communicating a discovery service location to the external service provider.

7. A method as recited in claim 1 further comprising prior to receiving a request, registering the service provider identifier with the discovery service to form a registered service provider identifier.

8. A method as recited in claim 7 further comprising when the service provider identifier is a preregistered service provider identifier, performing the step of parsing.

9. A system comprising:

a discovery service registering an external service provider and storing a token for the external service provider;

a user device forming a common domain cookie comprising a list of identity location identifiers;

said external service provider receiving a request for restricted content from the user device, forming a redirection request based on the request for restricted content, an external service provider identifier and, a return response location identifier; and

said discovery service receiving the redirection request from the external service provider with the common domain cookie, when the redirection request originates from the external service provider that is registered, the discovery service parsing the redirection request to obtain a previously used identity provider location identifier from the list of identity location identifiers within the common domain cookie and the external service provider identifier, said discovery service generating a response based on the return response location identifier with the previously used identity provider location identifier;

said external service provider receiving the response, generating an authentication request with the previously used identity provider location identifier and communicating the authentication request to the identity provider based on the identity provider location identifier;

said identity provider authenticating the user device; and

said user device accessing the restricted content based on authenticating.

10. A system as recited in claim 9 wherein the user device comprises a mobile user device.

11. A system as recited in claim 9 wherein the common domain cookie comprises a last used identity provider identifier.

12. A system as recited in claim 9 wherein the discovery service parses the request when the external service provider is a preregistered service provider.