The time a person spends on different smartphone apps is enough to identify them from a larger group in more than one in three cases say researchers from Lancaster University, and warn of the implications for security and privacy. The researchers warn that software granted access to a smartphone’s standard activity logging could render a reasonable prediction about a user’s identity even when they were logged-out of their account. An identification is possible with no monitoring of conversations or behaviours within apps themselves. Therefore, it is important to acknowledge that app usage data alone, which is often collected by a smartphone automatically, can potentially reveal a person’s identity. While providing new opportunities for law enforcement, it also poses risks to privacy if this type of data is misused.