Please find attached for the iOS SDK.
The SDK will make a Postback URL Call to CAKE once an app has been installed and opened.
Within the ReadMe file, you will see that you can choose which device fingerprint to pass along in the Postback URL call.
You can include multiple "Keys" on this call that could include the IDFA, Mac Address, UDID etc.
Attached are the two versions, one is for configuring the iOS app with Swift - ios-swift 2, and the other is for non-swift - ios-objc 2. To implement an SDK, the files can be added to the developers app.