iOS does not have a general purpose "permissions" system. It does, however, ask for permission (via a modal popup with an explanation) before performing some th

iOS does not have a general purpose "permissions" system. It does, however, ask for permission (via a modal popup with an explanation) before performing some things that you might to deny, such as accessing your photo library or physical location. (However, most likely for legacy reasons, the Contacts isn't protected in the same way.) It's also enforced through the review process: in addition to checking for stability and compatibility, the iOS review process also checks for malware and some data theft. This is also helped by the fact that iOS apps cannot dynamically load code after the review process, so you can be pretty sure that Apple at least took a quick look at what you install. It's far from foolproof — I'm sure a dedicated attacker could sneak something through the review process and steal your contacts — but nothing has happened so far (at least as far as I know). (As a side note about the lack of a true "permissions" system: having the app request access when it makes sense (Twitter only asks for location when I tap the geotag button, for example) means that I know why the app is asking, rather than on Android where I've seen frantic messages in the description to explain why the app needs some theoretically-privacy-invading permission, even if it's only used for a minor feature, since just asking for that permission scared users away. Neither system is perfect, but a contextual system where you can allow or deny individual permissions (as on iOS) combined with full coverage of what permissions might be wanted to be controlled (as on Android) would work pretty well.)