"The attacks in Paris once again demonstrated the scale of the terrorist threat that we face and the need to have robust powers through our intelligence and security services and policing to keep our people safe," said Cameron in a speech at an event in Nottingham, England.
"The next government will have to legislate again (on counter-terrorism efforts) in 2016. What I can say is, if I am Prime Minster, I will make sure we do not allow terrorists safe space to communicate with each other."
Ernest Hilbert, the EMEA head of cyber practise at corporate investigations and risk consultancy Kroll, said it would be impractical for the U.K. government—or any other—to wholesale ban encrypted apps. However, he said the government could legislate for the right to break into those that provided no "back door" means for police or intelligence to garner data from them.
"There is no way that any government—be it U.K., U.S. or Russia—is going to accept that there are types of apps out there that they have no access to," Hilbert told CNBC Tuesday. "There is no encryption that cannot be broken with enough time, energy, effort and resources."
Apple was not immediately available for comment. It states on its website: "Apple has never worked with any government agency from any country to create a 'back door' in any of our products or services. We have also never allowed any government access to our servers. And we never will."
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