Question about deviceUniqueIdentifier consistency?

I'm trying to set up an account recovery feature in my game based on the device's UDID. I'm having some issues with deviceUniqueIdentifier and was hoping for some clarification.

First, I noticed that on pre-iOS7 devices, the value returned by deviceUniqueIdentifier seems to always be consistent, so that's great.

On iOS7, I'm finding that the value returned by deviceUniqueIdentifier is different for each fresh install of the game. It seems to be consistently the same value for every run of the game, but if I uninstall the game and reinstall it with XCode to test account recovery, I find that deviceUniqueIdentifier is returning a different value.

Is this the expected behavior? I was imagining it would stay the same between installs. Is this an issue that only arises when building to device and not to the store? It seems that Unity's code is checking the VendorID before checking the AdvertisingID; would the AdvertisingID be more consistent?

 

Hey guys!

Actually deviceUniqueIdentifier is really confusing on iOS and even may lead to your app rejection by Apple.
As described in deviceUniqueIdentifier docs, at iOS7+ it tries to use VendorID first. As we can read out from identifierForVendor docs, it can be inconsistent for enterprise apps depending on iOS version (iOS 6 and iOS7 values may be not the same for same enterprise app).
Another inconsistency cause - ad-hoc apps installation.
And another one: "The value changes when the user deletes all of that vendor’s apps from the device and subsequently reinstalls one or more of them". It's not clear for me if vendor id should change on usual app update or not.

If deviceUniqueIdentifier can't read from identifierForVendor for some reason, it will try to read from advertisingIdentifier.
As we can read from advertisingIdentifier docs, it is more suitable for usage for security and fraud detection needs even if app is not advertisingTrackingEnabled. But, we can use this API "only for serving advertisements", thus your app will be rejected from App Store if you use deviceUniqueIdentifier, but have no any AD stuff in app. Example:
"We found your app uses the iOS Advertising Identifier but does not include ad functionality. This does not comply with the terms of the iOS Developer Program License Agreement, as required by the App Store Review Guidelines." (PLA 3.3.12).
advertisingIdentifier may change in some rare cases as well (in case of device reset, for example).

So, deviceUniqueIdentifier in iOS looks not so reliable and even dangerous to use at all. This is how it looks from my point of view, of course, I'd glad to know I'm wrong here.

For now, I can't figure out which Unity APIs can give us consistent device ID or something, what could replace it on iOS.
I'm looking to conjunction of:

SystemInfo.deviceModel
SystemInfo.graphicsDeviceID
SystemInfo.graphicsDeviceVendorID
SystemInfo.processorCount
SystemInfo.processorType
SystemInfo.supportsAccelerometer
SystemInfo.supportsGyroscope
SystemInfo.systemMemorySize

APIs to get semi-unique device ID (should be more reliable than deviceUniqueIdentifier in terms of consistency, will be same for same devices though).
I can't find any consistency info on all these APIs. I'd be really glad to hear from Unity Tech guys if these APIs are return consistent values for same device for all iOS starting from 6 version thus I can rely on them in terms device ID generation, at least for same devices.

 

Hi,

Pretty old thread, but I still don't understand something.
Can we use the advertisingIdentifier directly in order to identify the device id of our users?
When we use the deviceUniqueIdentifier , it sometimes reset itself on app updates - not even uninstall-install, just updates...
So we want to start using the advertisingIdentifier directly, since we understand it not suppose to change easily, but as we understand according to Apple we shouldn't suppose to use it?