Apple isn’t giving us many options in iOS to identify users. One we have is identifierForVendor.
I have an app where users can create passes for Apple Wallet. It seems there are some scammers who create fake tickets and sell them to people 🤬.
I was thinking about including identifierForVendor in the pass, so if someone gets scammed and is motivated enough, he can bring this to the police.
Is this identifier something Apple can use to track user? So will it help in case authorities ask Apple for related data?
I know chances of finding these scammers are low, but I want to do something to make their life harder,
The identifierForVendor you are referring to is best known as IDFV. This unique identifier can be used to identify a user across applications from a specific publisher. As can be seen in the documentation:
"The value of this property is the same for apps that come from the same vendor running on the same device."
Other than this identifier, which can link a specific user across multiple applications made by the same publisher, there isn't much else there. Furthermore, this identifier in itself, doesn't give out a great deal of information.
Also, it is important to be aware that:
The value in this property remains the same while the app (or another app from the same vendor) is installed on the iOS device. The value changes when the user deletes all of that vendor’s apps from the device and subsequently reinstalls one or more of them.
So I wouldn't count on this identifier for anything much, especially in your case where fraud is considered.
If you want to learn more about the different identifiers (iOS/Android), I wrote an article about them a while back.
To make scammers' lives a bit harder, you would probably have to be able to identify them from your application using a unique identifier (UUID) you create that is associated to a specific phone/account. But that is something that is worth to look deeper into to understand all the considerations.