Think about your home's security measures. You rely on structural features—secure locks, a solid foundation, strong windows and doors. You can also have an alarm or video camera, for an extra layer of security, with a support team behind these tools, making them more powerful, but all but invisible until you need them.
Android developers have a similar approach to how they roll out Android security improvements . As part of the Android foundation, they built security measures like app sandboxing, which restricts apps, minimizing their ability to harm other parts of your phone. But just like in your home, Google offers a built-in “service layer” (sort of like the phone of that alarm service for your home) to most Android users , which is constantly being enhanced, and it’s free. They’ve also added to that service layer, more robust measures for your Android phone or tablet.
More: https://officialandroid.blogspot.nl/2014/04/expanding-googles-security-services-for.html
