When former Secretary of State Hillary Clinton was pushing to get a waiver allowing her to use a BlackBerry like President Barack Obama back in 2009, the National Security Agency had a very short list of devices approved for classified communications. It was two devices built for the Secure Mobile Environment Portable Electronic Device (SME PED) program. In fact, those devices were the only thing anyone in government without an explicit security waiver (like the one the president got, along with his souped-up BlackBerry 8830) could use until as recently as last year to get mobile access to top secret encrypted calls and secure e-mail.
Despite $18 million in development contracts for each of the vendors selected to build the competing SME PED phones (or perhaps because of it), the resulting devices were far from user-friendly. The phones - General Dynamics' Sectéra Edge and L3 Communications' Guardian - were not technically "smart phones," but instead were handheld personal digital assistants with phone capability, derived from late 1990s and early 2000s technology that had been hardened for security purposes - specifically, Windows CE technology.
This is an absolutely fascinating piece of technological history here. Can you imagine using one of these monstrous things?