setStorageDeviceProtected
Explicitly set the storage location used internally by this class to be device-protected storage.
On devices with direct boot, data stored in this location is encrypted with a key tied to the physical device, and it can be accessed immediately after the device has booted successfully, both before and after the user has authenticated with their credentials (such as a lock pattern or PIN).
Because device-protected data is available without user authentication, you should carefully limit the data you store using this Context. For example, storing sensitive authentication tokens or passwords in the device-protected area is strongly discouraged.
Prior to API 24 this method has no effect, since device-protected storage is not available.