Sun OpenSSO Enterprise 8.0 Technical Overview

Authentication Web Service

The Authentication Web Service is for provider-to-provider authentication. SOAP defines an XML-based messaging paradigm, but not security mechanisms for message protection; particularly, they do not describe user authentication. To secure SOAP messages, the Authentication Web Service was implemented based on the Liberty ID-WSF Authentication Service and Single Sign-On Service Specification. The specification defines a protocol that adds the Simple Authentication and Security Layer (SASL) authentication functionality. Upon successful authentication, the final Simple Authentication and Security Layer (SASL) response contains the resource offering for the Discovery Service.

Note –

The Authentication Web Service is configured using the XML service file amAuthnSvc.xml and can be managed using the OpenSSO Enterprise console or this XML file. Additional administration information can be found in the Sun OpenSSO Enterprise 8.0 Administration Guide.

The following sections contain more general information.

Authentication Web Service Process

The exchange of authentication information between a web service consumer (WSC) and web service provider (WSP) is accomplished using SOAP-bound messages. The messages are a series of client requests and server responses specific to the defined SASL mechanism (or mode of authentication). The authentication exchange can involve an arbitrary number of round trips, dictated by the particular SASL mechanism employed. The WSC might have knowledge of the supported SASL mechanisms, or it might send the server its own list of mechanisms and allow the server to choose one. (The list of supported mechanisms can be found at SASL Mechanisms.) After receiving a request for authentication (or any response from the WSC), the WSP may issue additional challenges or indicate authentication failure or success. The sequence between the WSC and the Authentication Web Service (a WSP) is as follows.

  1. The authentication exchange begins when a WSC sends a SASL authentication request to the Authentication Web Service on behalf of a principal. The request message contains an identifier for the principal and indicates one or more SASL mechanisms from which the service can choose.

  2. The Authentication Web Service responds by asserting the method to use and, if applicable, initiating a challenge.

    Note –

    If the Authentication Web Service does not support any of the cited methods, it responds by aborting the exchange.

  3. The WSC responds with the necessary credentials for the chosen method of authentication.

  4. The Authentication Web Service replies by approving or denying the authentication. If approved, the response includes the credentials the WSC needs to invoke other web services, such as the Discovery Service.

Authentication Web Service API

The Authentication Web Service includes the following Java programming packages:

Together, the packages are used to initiate the authentication process and communicate authentication credentials to the Authentication Web Service. For more information, see the Sun OpenSSO Enterprise 8.0 Java API Reference and the Sun OpenSSO Enterprise 8.0 Developer’s Guide.

Which Authentication Service to Use?

The Authentication Web Service is not to be confused with the proprietary OpenSSO Enterprise Authentication Service. Architecturally, the Authentication Web Service sits on top of the OpenSSO Enterprise Authentication Service and the Web Services Stack framework. You might use the Authentication Web Service if you are a service provider and want to use a standards-based mechanism to authenticate users. Following are two use cases where the Authentication Web Service is preferable to the proprietary OpenSSO Enterprise Authentication Service:

In addition to providing an authentication service to verify credentials (for example, user ID and password), the Authentication Web Service provides the WSC with bootstrap information that contains the endpoint and credentials needed to access the Discovery Service. The WSC can ignore the bootstrap or use it to access other web services, such as the authenticated user's personal profile or calendar.

Note –

An authenticated enterprise might also use the bootstrap information to access a partner in a business-to-business environment.

Following is a scenario that shows how the Authentication Web Service interacts with the OpenSSO Enterprise Authentication Service. The WSC delegates all authentication to the identity provider and prefers PLAIN authentication which accepts a user identifier and password.

  1. The user attempts access to a service provider (not necessarily hosted by OpenSSO Enterprise).

  2. When the service provider (acting as a WSC) finds that the user is not authenticated, it invokes the identity provider Authentication Web Service by sending a SOAP request.

    Note –

    It is assumed that the identity provider is hosted by OpenSSO Enterprise where the OpenSSO Enterprise Authentication Service is configured for Certificate and LDAP authentication and the Authentication Web Service has mapped LDAP to its own PLAIN authentication mechanism)

  3. After inspecting its configuration, the Authentication Web Service sends back a response indicating that it supports Certificate and PLAIN authentication.

  4. The service provider decides on PLAIN authentication and prompts the user for an identifier and password.

  5. The service provider receives the user identifier and password and sends it to the identity provider.

  6. The identity provider passes the credentials to the locally hosted LDAP Authentication module using the proprietary OpenSSO Enterprise Authentication Service Java API.

  7. The LDAP Authentication module verifies the credentials by accessing the user's personal profile (hosted by a third-party product).

  8. The Authentication Web Service is notified of the verification and sends a response to the service provider indicating successful authentication. If configured to do so, it also includes bootstrap information formatted using XML and containing the Discovery Service endpoint and a token to invoke it.

  9. The service provider parses the response, verifies that it is a successful authentication, and provides the service to the user.

At some point the service provider might need to access the user's personal profile. To do this, it will use the bootstrap information received during this process to contact the Discovery Service and find where the profile is stored. The Discovery Service returns a resource offering (containing a token and the location of an endpoint), and the service provider uses that to invoke the Liberty Personal Profile Service.