It doesn't need to be perfect. Only hard enough that apps have to resort to more desperate techniques, so that they're detectable and Apple can ban them for trying.
Overall I don't like Apple's sandbox and total control over iOS, but it exists, and in this case at least they can use their power for something good.
The whack-a-mole1 aspect of Apple’s new privacy rules is that while Apple can restrict access to the API that provides access to the IDFA identifier, clever developers can find (perhaps infinite) other ways to combine things they do have access to into a unique, or even just “close enough to unique to be useful for tracking”, identifier. IP addresses, to name just one example, are a big factor that Apple can’t block would-be-trackers from using.The more access your app wants, the more randomness should be introduced.
IP addresses and battery levels are dynamic and screen resolution and time zones are shared by millions.
The real fingerprinting is in things like sensor calibration and these can be stopped by binning or randomizing values.
Apple has announced they will be blocking these prints one by one and they are.
Developers wouldn’t be screaming if they weren’t in trouble.
clever developers can find (perhaps infinite) other ways to combine things they do have access to into a unique, or even just “close enough to unique to be useful for tracking”, identifierUnless Apple decides to implement some form of VPN to obscure the IP there's not much to do about that, the phone can hide it only from the app, not the server. On a mobile network this seems less of a concern, and even in the home it wouldn't allow unique identification. So assuming the IP was the only thing that leaks and every other data point is "poisoned" by the OS, I'm sure it would make those companies tracking you deeply unhappy and unsatisfied.
Maybe some loopholes can't be closed, others may provide precise data but it's shared with millions of users making it as generic as it gets. Just raising the bar for successfully tracking the user to a very hard to reach level, and lowering the overall accuracy to the point it's no longer a practical concern could be good enough for all intents and purposes.
Again, Apple knows these fingerprinting parts exist, has acknowledged they exist, has stated they are going to block them and has blocked them. And no, they aren’t done, they might never be done. But also they have stated no intention of stopping.
Why would tracking companies be grasping for straws like boot up time if these other obvious things are so effective and impossible to block?
And by the way, there is absolutely nothing stopping Apple from reporting your app was installed on January 1st, 1970.
I doubt Apple would do that but I think you are very much missing the point. These one-off patches are not effective at scale, there are literally 100s if not 1000s of information leaks of this type that indeed are observable across multiple apps. App install date was just one that I pulled from thin air that required no thought. A dedicated engineer could easily solve this problem.
Yes. I've been wanting Apple to launch a VPN service for a long time.
A commercial VPN service can aid privacy by aggregating thousands of users behind a single IP address. The problem is that you have to trust the VPN provider. Commercial VPN providers are inherently shady -- after all, their entire business model is aiding and abetting copyright infringement or perhaps even worse activities. (No logging, wink wink!) I see no reason to trust them.
By contrast, Apple has a valuable brand (i.e., a reputation) and has made privacy a core part of their sales pitch. Unlike the inherently fly-by-night commercial VPN industry, Apple would have billions of reasons not to betray their customers by selling VPN usage data.
I think there's a market for an existing, known, reputable business to come in and offer a VPN service that explicitly does keep traffic flow logs for a short time, in the same way that ISPs retain dynamic IP assignment logs for a short time. By retaining logs, you avoid the shady elements that are otherwise attracted to no-logging VPN services.
If not Apple, I think one of the few remaining reputable independent ISPs would be a great fit. Sonic.net comes to mind. Sonic makes [clear, explicit claims](https://www.sonic.com/privacy-policy) that they do not sell usage data, but they do retain IP assignment logs for up to 14 days and will provide that data to law enforcement with an appropriate court order. That's exactly what I want: my adversary is P&G and their ilk, not law enforcement with a court order.
https://developer.apple.com/library/archive/documentation/De...
The idea of a “trustless” App Store is nice and roughly works in practice but is ultimately a fiction. Using a malicious app will always expose you to danger. New vulnerabilities are announced regularly. The situation is worse on the web: WebKit vulns are released nearly monthly and there is no app review there. Browsing the web with JavaScript enabled is a security nightmare. For example see the recent security notes for iOS 14.4.2 [1], every release you’ll likely see a fix for a new vulnerability.
I’m hesitant to say there will ever be a scalable and permanent solution to this problem. The best advice is simple: do not run apps you do not trust, do not visit websites you do not trust.
[1] https://support.apple.com/en-us/HT212256