One of the more common methods in past years was for users to “jailbreak” their iOS devices, installing a modified version of the operating system that loosens many of the restrictions that Apple has placed in iOS, for better of for worse, including the need for apps to be signed. Sadly, there have been few ways to get around Apple’s restrictions and install apps from other sources. This requirement is built into the core operating system so that it can’t be easily bypassed. So even if a user is able to get some random app onto an iOS device, the device will refuse to run it if it doesn’t recognize a valid signature. Everything that Apple issues on the App Store bears this signature, as do apps distributed through developer beta programs like TestFlight.
The secret to Apple’s control is by requiring iOS to only accept and run apps that are cryptographically “signed” with a valid certificate that’s issued by Apple. While Apple has lowered its take for long-term subscriptions, this hasn’t stopped accusations of the App Store being a monopoly on more than one occasion.
Then there are the financial considerations, with Apple taking a cut of the revenue that developers make from their apps, both in terms of outright sales and in-app purchases and subscriptions.
