India, Aug. 30 -- By now, our smartphones know us better than most of the people in our lives ever will.

Which means, of course, there are secrets at stake in our phones, as well as information: passcodes, bank balances, location and spending histories; images and videos that could be morphed; voice notes that could be altered or played back in attempts at blackmail or fraud.

Enter the guardians of our galaxies. Phone protection systems are stepping into the future, with quantum encryption, behavioural analysis, machine-learning.

At the forefront of this fight are smartphone operating systems themselves.

Apple's iOS and Google's Android have evolved into watchful gatekeepers that track app behaviour and usage trends as part of an effo...