  Over the years, use of smartphones has come to dominate several areas,
improving our lives, offering us convenience, and reshaping our daily work
circumstances. Beyond traditional use for communication, they are used for many
peripheral tasks such as gaming, browsing, and shopping. A significant amount
of traffic over the Internet belongs to the applications running over mobile
devices. Applications encrypt their communication to ensure the privacy and
security of the user's data. However, it has been found that the amount and
nature of incoming and outgoing traffic to a mobile device could reveal a
significant amount of information that can be used to identify the activities
performed and to profile the user. To that end, researchers are trying to
develop techniques to classify encrypted mobile traffic at different levels of
granularity, with the objectives of performing mobile user profiling, network
performance optimization, $etc.$ This paper proposes a framework to categorize
the research works on analyzing encrypted network traffic related to mobile
devices. After that, we provide an extensive review of state of the art based
on the proposed framework.
