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The reason why Apple requires you to press the physical side button to confirm a purchase with Apple Pay or in the App Store is because pressing the side

by kylec 9y ago

The reason why Apple requires you to press the physical side button to confirm a purchase with Apple Pay or in the App Store is because pressing the side button can’t be faked by an app. If it was an on-screen button, a nefarious app could present a fake Apple Pay button. With any normal app, clicking the side button once will always lock the screen, and double-clicking will put you in Apple Pay mode. Only Apple’s own software can override the side button like this. Double clicking the side button to confirm a purchase effectively guarantees that it was a legitimate payment experience. To what end? You don't enter a password or anything when using Apple Pay, so the only thing this "nefarious" app could do is trick you into thinking that you paid for something you didn't. And wouldn't this sort of thing get caught in app review and/or get the app yanked from the store when discovered? I honestly can't figure out what the downside would be to having a "pay with Apple Pay" button on the screen. As an aside, I don't like having to press the side button for Apple Pay on my iPhone X. I usually have to shift how I'm holding it to get the proper leverage to double-press the button. Double pressing the home button was way easier.

abalone 9y ago
Right, Gruber's theory is poorly supported. He should detail a "fake" software UI scenario that the side button protects against, because I'm not seeing a single one. A fake pay button couldn't do anything more with the Apple Pay system modal UI than present it. It can't trick you into completing it. The side button click adds nothing. The side button doesn't stop it from presenting a fake payment UI. And furthermore the App Store is a first party app so requiring the side button there can't possibly be to protect from nefarious apps. A better theory is they just want total UI consistency. Since they need to use the side button for in-store Apple Pay, that wins for the App Store and in-app purchases as well. But even that doesn't quite make sense either, because then why are they requiring it for installing free apps?
mehrdada 9y ago
The way Gruber phrased his post makes me feel like he has been told some facts about this and not merely speculating. It could be the case that the physical button is trapped directly by the secure enclave system and the goal is not to prevent an app from accidentally fooling you in the UI, but to prevent any iOS software to silently ask the secure enclave to authenticate something without a physical confirmation directly from the user.

by kylec 9y ago

abalone 9y ago

Right, Gruber's theory is poorly supported. He should detail a "fake" software UI scenario that the side button protects against, because I'm not seeing a single one. A fake pay button couldn't do anything more with the Apple Pay system modal UI than present it. It can't trick you into completing it. The side button click adds nothing. The side button doesn't stop it from presenting a fake payment UI. And furthermore the App Store is a first party app so requiring the side button there can't possibly be to protect from nefarious apps. A better theory is they just want total UI consistency. Since they need to use the side button for in-store Apple Pay, that wins for the App Store and in-app purchases as well. But even that doesn't quite make sense either, because then why are they requiring it for installing free apps?

mehrdada 9y ago

The way Gruber phrased his post makes me feel like he has been told some facts about this and not merely speculating. It could be the case that the physical button is trapped directly by the secure enclave system and the goal is not to prevent an app from accidentally fooling you in the UI, but to prevent any iOS software to silently ask the secure enclave to authenticate something without a physical confirmation directly from the user.