BlackBerry continues to shift its focus from selling mobile phones to securing them—as well as other portable devices, and increasingly connected items that are part of the Internet of things. “All of our investments and acquisitions go to one thing, to make the most secure mobile platform that the industry has to offer,” said John Chen, BlackBerry executive chairman and CEO, kicking off a morning of presentations at the company-sponsored BlackBerry Security Summit, held Thursday in New York.