We'd need more information. SSO is usually provided via a plugin module to whatever security framework you are using. For example, the "CAS" SSO system has a Tomcat Realm plugin.
SSO is not generally coded into apps, since there are many reasons why it's preferable that security be an external matter - not least of which is that most developer-designed security systems are anything BUT secure. Instead, the security is applied externally. The Tomcat security Realm, for example, is an implementation of the Container-Managed Security component of J2EE and JEE.
"privilege" comes from the Latin words for "private" and "law" (legal) and dates to feudal times. To "claim privilege" meant that you were above the laws that applied to the common people.
You guys wanna see my fabulous new place? Or do you wanna look at this tiny ad?
Devious Experiments for a Truly Passive Greenhouse!