A Unique Identifier (UID) is a unique, multi- digit numeric or alphanumeric identifier for components, devices, software, people and documents. It is unique, manufacturer- and platform-independent, and can be assigned to individual entities in distributed systems. Entities can be addressed and included in communication via the unique identifier.
A Unique Identifier can be a serially incremented serial number, a random number or a central registration number. In addition to the applications mentioned above, the UID number is also used in the Electronic Product Code( EPC), among others.
Unique identifiers are used in many network areas, in information technology and on the Internet. For example, the Uniform Resource Identifier( URI) uniquely identifies all content, text, video, audio and image resources available on the global Web.
The Uniform Resource Locator( URL) stands for the Internet address that is provided to the user via the browser. In addition, there is also the Universal Unique Identifier( UUID), which uniquely identifies all objects on the Internet with its 128-bit identification. Another identifier is the Global Unique Identifier( GUID), whose identifier was implemented after UUID. Apple has identified certain devices with the 40-digit Unique Device Identifier( UDID), and WLANs are identified with the Service Set Identifier( SSID).