Mike Perry of @TorProject: "…the Copperhead project began producing hardened builds of Android. The hardening features make it more difficult to exploit Android vulnerabilities, and also provides WiFi MAC address randomization, so that it is no longer trivial to track devices using this information. Copperhead is also the only Android ROM that supports verified boot, which prevents exploits from modifying the boot, system, recovery, and vendor device partitions. Coppherhead has also extended this protection by preventing system applications from being overridden by Google Play Store apps, or from writing bytecode to writable partitions (where it could be modified and infected). This makes Copperhead an excellent choice for our base system."