Amazon's $50 Fire tablet, which runs Fire OS 5. (credit: Mark Walton) In the wake of Apple's high-profile fight with the FBI, more users and journalists have been paying attention to encryption of local storage in phones and tablets. Apple began encrypting all devices by default in iOS 8. Google made encryption a requirement for all Google-approved Android phones that ship with Marshmallow (after a false start in Lollipop), and it has been available as an optional Android security feature for years. Amazon's Fire OS is a fork of Android, based on the Android Open Source Project (AOSP) code but without Google's apps and services or guaranteed compatibility with apps developed for Google-approved Android.