Gets the security identifier (SID) for the user.
Assembly: mscorlib (in mscorlib.dll)
The SID uniquely identifies a user or group on all Windows NT implementations.
The WindowsIdentity object returned by the GetAnonymous method is not the same as the Windows anonymous user. This property gets null for an anonymous user represented by the WindowsIdentity object returned by the GetAnonymous method; it does not get the SID representing an anonymous Windows user.