With iOS 6 release, Apple introduced a new class to create universally unique identifiers (UUID) aka globally unique identifiers (GUID).
The class NSUUID implements RFC 4122 creating values that are 128 bits long and guaranteed to be unique across space and time by using a unique value on the device as well as a value representing the elapsed time since October 15, 1582 at 00:00:00.
Here is how to generate a UUID in iOS 6:
// Get UUID value NSUUID *uuid = [NSUUID UUID]; // Convert UUID to string and output result NSLog(@"UUID: %@", [uuid UUIDString]);
The output looks something like this: