Yep, you read that right. In a Late Night with Jimmy Fallon appearance a couple of days back, President Obama mentioned he no longer used his DISA/DOD-approved Blackberry, but a new Android smartphone instead. According to Ars Technica, that device is very likely a hardened Samsung Galaxy S4.
The S4 is currently the only device supported under DISA's DOD Mobility Classified Capability-Secret (DMCC-S) program. In 2014, a number of Samsung devices were the first to win approval from the National Security Agency under its National Information Assurance Partnership (NIAP) Commercial Solutions for Classified (CSfC) program—largely because of Samsung's KNOX security technology.