The QSW_UUID Framework is an Objective-C wrapper for the Core Foundation CFUUID.h header at /System/Library/Frameworks/CoreFoundation.framework, with additional features.

The framework provides methods that call CFUUID functions to generate universally unique identifiers, both as raw binary and string objects, and to convert any UUID between its binary and string representations. In addition, it provides methods to test individual UUIDs for valid representation formats, and to test pairs of UUIDs for equality and ordering, all in accordance with the UUID specification. Nil UUIDs are supported. Finally, it provides methods to obtain the version and variant of the specification under which a UUID was created.

A universally unique identifier (UUID) is an identifier that is unique across the space of all UUIDs generated using the same algorithm and unique across time. It can be used to reliably identify and distinguish persistent objects in many contexts, such as identifying remote procedure calls on the internet, identifying header files in software, and identifying individual records in multiple databases. The algorithm used here will generate unique UUIDs until approximately 3400 A.D.