docs: document biometric encryption and refine security model descrip… #2087

Job	Run time
Build (Unit-tests & Android-Lint)	2h 55m 20s
Android UI-tests on emulator (27, default)	9m 37s
Android UI-tests on emulator (28, default)	6h 0m 4s
Android UI-tests on emulator (25, default)	8m 50s
Android UI-tests on emulator (23, default)	12m 12s
Android UI-tests on emulator (26, default)	8m 50s
Android UI-tests on emulator (33, default)	11m 42s
Android UI-tests on emulator (24, default)	8m 37s
Android UI-tests on emulator (30, default)	8m 37s
Android UI-tests on emulator (29, default)	10m 13s
Android UI-tests on emulator (31, default)	12m 46s
Android UI-tests on emulator (36, default)	10m 22s
Android UI-tests on emulator (35, default)	12m 47s
Android UI-tests on emulator (32, default)	13m 4s
Android UI-tests on emulator (34, default)	10m 35s
Android UI-tests on emulator (37, default)	44s
	11h 14m 20s

Navigation Menu