Apple's iPhones, iPads and other devices running iOS 6 or higher are officially cleared for use on the US government's secure networks, the Department of Defence announced on Friday. The final approval, which we first reported on in March, also grants Samsung Android devices that are running the Korean company's Knox security lockdown, as well as BlackBerry devices running BB10 the ability to be used on secure networks. The move is expected to further hurt BlackBerry, as it faces competition in the military space for the first time.