With each new Android release, Google adds more security features to harden Android. Two security features in Android 4.4 KitKat are particularly notable because they are Linux kernel developments. Security-enhanced Linux (SELinux) policies are fully enabled in KitKat, and dm-verity was added. Both features improve the integrity and trust of the Android operating system.
This builds on Google's earlier work to tighten Android’s defenses against attackers, such as full-disk encryption (dm-crypt) added to Android 3.x and Address Space Layout Randomization (ADLR) and Data Execution Protection (DEP) in Android 4.1."
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