Note that the Samsung Galaxy S4 -- or, more correctly, a specially "hardened" version of it -- is the only device supported by DISA's DoD Mobility Classified Ca

Note that the Samsung Galaxy S4 -- or, more correctly, a specially "hardened" version of it -- is the only device supported by DISA's DoD Mobility Classified Capability-Secret (DMCC-S) program. An S4, protected by this "Knox" system, is the device that replaced President Obama's Blackberry 8830. In addition, Secretary of State John Kerry was reportedly an early beta tester of this "special version" of the S4.