Defines the name identifier formats supported by the attribute query provider. Name identifiers are a way for providers to communicate with each other regarding a user. Single sign-on interactions support three types of identifiers:
An X509SubjectName defines the subject name of the X509 encryption type.
A persistent identifier is saved to a particular user's data store entry as the value of two attributes.
A transient identifier is temporary and no data will be written to the user's persistent data store.