Systems and methods for operating a computing system. The methods comprise: obtaining, by a first computing device, an original Security Identifier (“SID”); transforming, by the first computing device, the original SID into a composite SID by modifying the original SID to include at least (a) an SID format value indicating a structural format of an SID and (b) a pointer specifying a memory location at which non-SID authentication information is stored or a customer number indicating an entity to which a user is associated; and using the composite SID by the first computing device during SID based operation.