iOS UUID library as alternative to the old good UDID and identifierForVendor.

This library provides the simplest API to obtain universally unique identifiers with different persistency levels.
All methods can be called as static methods or via the shared instance.

It's possible to retrieve the UUIDs created for all devices of the same user, in this way with a little bit of server-side help it's possible manage guest accounts across multiple devices easily.

##Requirements & dependencies

• iOS >= 5.0
• ARC enabled
• Key-value storage enabled (target / Capabilities / iCloud / Key-value storage)
• Security.framework
• UICKeyChainStore
• (optional) KeyChain sharing enabled if you need to share the same uuidForDevice / uuidsOfUserDevices values accross multiple apps.

##Installation

####CocoaPods: pod 'FCUUID'

####Manual install:

• Copy FCUUID.h and FCUUID.m to your project.
• Manual install UICKeyChainStore

##Usage setup

• Add an observer to the FCUUIDsOfUserDevicesDidChangeNotification to be notified about user devices changes.
• Call [FCUUID sharedInstance] or any other method in applicationDidFinishLaunchingWithOptions to start iCloud sync.

##API All the following methods (excluding the last one) return a different Universally Unique Identifier, each one with its own persistency level.

//changes each time (no persistent)
+(NSString *)uuid;

//changes each time the app gets launched (persistent to session)
+(NSString *)uuidForSession;

//changes each time the app gets installed (persistent to installation)
+(NSString *)uuidForInstallation;

//changes each time all the apps of the same vendor are uninstalled (this works exactly as identifierForVendor)
+(NSString *)uuidForVendor;

//changes only on system reset, this is the best replacement to the good old udid (persistent to device)
+(NSString *)uuidForDevice;

//returns the list of all uuidForDevice of the same user
//in this way it's possible manage guest accounts across multiple devices easily.
+(NSArray *)uuidsOfUserDevices;

Enjoy :)