In contrast with macOS, which is mainly developed for PC use cases, iOS is relatively new and was created to power mobile devices—and this fact affects the security model introduced there with it. Other newer operating systems, such as watchOS and tvOS, are extensively based on it, so we will focus mainly on iOS in this chapter.
Similar to macOS, the development can be done in the objective-C and Swift programming languages, and the API in this case is called Cocoa Touch, which also includes mobile-oriented features, such as gesture recognition. All iOS-powered devices use ARM-based processors.
Now, let's take a look at the different layers of protection implemented in iOS.