That is a job that requires well over a hundred decisions, an unmanageable number for the typical user, researchers from Carnegie Mellon University (CMU) in the US said.

The privacy assistant can learn the user's preferences and quickly recommend the most appropriate settings, such as with which app to share the user's location, or contact list.
In the field test, people accepted almost 80 per cent of the recommendations made by the privacy assistant and, at the end of the study, these people indicated they were more comfortable with their privacy settings than users who did not have a privacy assistant, researchers said.

"It is clear that people just cannot cope with the complexities of privacy settings associated with the apps they have on their smartphones," said Norman Sadeh from CMU.

"And its not just smartphone apps. The growing number of sensors and other smart devices that make up the so-called internet of things will impact privacy and make it even more challenging for users to retain control over their data and how it is being used," said Sadeh.

In the study, the app recommended settings for the users, which they could accept or reject. But eventually a privacy assistant may prove trustworthy enough to automatically make many of those decisions, researchers said.
"Previous studies have shown that most people are unaware of many of the privacy settings for their apps, or are not comfortable with the permissions they consented to at some earlier point," said Sadeh.
Sadeh's research has shown people's preferences can generally be organised in a small number of categories or "profiles" that differ based on people's willingness to grant different types of applications access to their information.

The privacy assistant can determine to which of these categories a person belongs. "Machine learning techniques enable the assistant to analyse a user's response to a small number of questions focusing on the particular apps they have on their phones," said Bin Liu from CMU.

In the study, 49 people used the privacy assistant and 23 did not. Those using the privacy assistant adopted almost 80 per cent of its privacy recommendations, researchers said.

Both groups were then sent daily "privacy nudges," messages alerting them to what may be surprising behaviour by apps. Such a nudge might note that a certain app or set of apps had shared their location with a third party multiple times.

Over the course of the study, participants changed only 5 per cent of the settings that had originally been recommended to them by the personal privacy assistant, researchers said.
"Our findings suggest that the personal privacy assistant does a good job of properly profiling each user and that its recommendations based on those profiles were useful," said Sadeh.