UIDevice

UIDevice is a singleton class that provides access to some properties of the current device.

As a client to liblockdown

Many important properties can be accessed via liblockdown. This can be used to bypass higher-level spoofing hacks. One has to use the liblockdown functions in MobileSubstrate initializers because UIKit was not ready at that time.

UIDevice property	liblockdown key
model	kLockdownDeviceClassKey
localizedModel	kLockdownDeviceClassKey
uniqueIdentifier	kLockdownUniqueDeviceIDKey
buildVersion	kLockdownBuildVersionKey
systemVersion	kLockdownProductVersionKey
name	kLockdownDeviceNameKey
identifierForVendor	unknown
advertisingIdentifier	unknown

iPad mode (Wildcat)

Signature	@property(assign,nonatomic) BOOL isWildcat;
Available in	3.2 —

iPad (codenamed Wildcat) has a drastically different user interface than iPhone/iPod Touch, but all three share the same OS. In UIKit and SpringBoard, this property is heavily used to determine which behavior should be used.

It is recommended that you check against the public userInterfaceIdiom instead of using this property.

LaunchServices (LS) Identifiers

The identifiers are stored in the following file: /private/var/db/lsd/com.apple.lsdidentifiers.plist The launch services daemon (lsd) manages this file.

property	lsidentifiers key
advertisingIdentifier	LSAdvertiserIdentifier
identifierForVendor AppStore app	Vendor Name (e.g. Google, Inc.)
identifierForVendor Xcode deployed app	BundleID:[first parts of app's bundle ID] (e.g. com.malcolmhall)
identifierForVendor /Applications app or daemon	Path:[ExecutableName] (e.g. Path:pmpd)

Each lsidentifiers key (except advertising) contains a dictionary using following keys:

key	description
LSVendorIdentifier	a UUID (aka GUID)
LSApplications	In the case of Path: it is the list of paths e.g. /private/var/stash/Applications.zcoj2b/UDIDTest4.app/UDIDTest4. In the case of BundleID:[com.vendor] or VendorName it is a list of bundle IDs.

It appears that when you install your app to /Applications and execute uicache, LaunchServices fills in the "identifierForVendor Xcode deployed app". However when you actually run your app and access the identifier it then fills in the "identifierForVendor /Applications app" with a different ID and the app uses that one. This means you can't share the same ID for an app you are developing by both deploying from Xcode and also copying to \Applications.

These identifiers are backed up however they will change if the user restores their backup to a new device, according to the Apple docs but not fully verified. This stack overflow user has done some testing: http://stackoverflow.com/questions/16520231/under-what-conditions-is-apples-advertisingidentifier-reset

References

• Official reference: UIDevice
• Header: http://github.com/kennytm/iphone-private-frameworks/blob/master/UIKit/UIDevice2.h