An Identity descriptor is a wrapper for the identity type (Windows SID, Passport) along with a unique identifier such as the SID or PUID.
Optional
The unique identifier for this identity, not exceeding 256 chars, which will be persisted.
Type of descriptor (for example, Windows, Passport, etc.).
An Identity descriptor is a wrapper for the identity type (Windows SID, Passport) along with a unique identifier such as the SID or PUID.