Device encryption
Android
http://www.giga.de/apps/android/gallery/android-geraet-verschluesseln-so-funktioniert-s
Windows Phone
Users can set up individual encryption on Windows Phones that have at least version 10 of the Microsoft operating system. With version 8 and earlier, the only option is to create encryption using group guidelines, which unfortunately is not a workable solution for end users.
http://techmixx.de/windows-10-mobile-smartphone-verschluesseln
Blackberry
Because the Blackberry support websites are frequently revised, the links become quickly outdated. For this reason we have to ask that you research this topic on your own: Blackberry Support
You can streamline your search by knowing the exact model and operating system version. Help is available at: de.blackberry.com/support/identify.html