Method and system for authenticating service providers to communicate with a primary service provider

A method and system for authenticating a user device includes an identity provider reading service and an external service provider receiving a request to access content from a user device and communicating the request to access content from a service provider to the reading service. The request to access content includes cookie data. The external service requests an identity provider token from the cookie data from the reading service based on the request to access. The identity provider reading service communicates the identity provider token to the external service provider. An identity provider communicates with the service provider. The external service generates and communicates an authentication request to the identity provider having the identity provider token and a service provider identifier. The identity provider communicates an assertion signal to the service provider when the cookie data is resolved at the identity provider. The service provider grants access to content to the user device in response to the assertion signal.