Single Sign-on
Microsoft Office SharePoint Server 2007 provides a default single sign-on (SSO) service for the storage and mapping of credentials for use in connecting with third-party or back-end systems. Many companies already have developed an in-house credential storage system or use a solution other than Microsoft Single Sign-On. Instead of maintaining credential mapping in two places, Office SharePoint Server 2007 provides a mechanism, pluggable SSO, to specify an alternate SSO Provider to the standard SSO Provider in Office SharePoint Server 2007.
Replacing the default SSO Provider, SpsSsoProvider, in Office SharePoint Server 2007 involves implementing the Microsoft.SharePoint.Portal.SingleSignOn.ISsoProvider, installing it into the global assembly cache, and registering the new SSO provider with Office SharePoint Server 2007.
At any time, you can only register a single SSO Provider for Office SharePoint Server 2007. Registering a new SSO Provider replaces SpsSsoProvider in Office SharePoint Server 2007.
Most providers will need to implement the GetCredentials and GetSsoProviderInfo methods of the ISsoProvider interface.