As users conveniently stream their favored online videos, video request
records will be automatically seized by video content providers, which may leak
users' privacy. Unfortunately, most existing privacy-enhancing approaches are
not applicable for protecting users' privacy in requests, which cannot be
easily altered or distorted by users and must be visible for content providers
to stream correct videos. To preserve request privacy in online video services,
it is possible to request additional videos irrelevant to users' interests so
that content providers cannot precisely infer users' interest information.
However, a naive redundant requesting approach will significantly degrade the
performance of edge caches and increase bandwidth overhead accordingly. In this
paper, we are among the first to propose a Cache-Friendly Redundant Video
Requesting (cRVR) algorithm for User Devices (UDs) and its corresponding
caching algorithm for the Edge Cache (EC), which can effectively mitigate the
problem of request privacy leakage with minimal impact on the EC's performance.
To solve the problem, we develop a Stackelberg game to analyze the dedicated
interaction between UDs and EC and obtain their optimal strategies to maximize
their respective utility. For UDs, the utility function is a combination of
both video playback utility and privacy protection utility. We theoretically
prove the existence and uniqueness of the equilibrium of the Stackelberg game.
In the end, extensive experiments are conducted with real traces to demonstrate
that cRVR can effectively protect video request privacy by reducing up to
57.96\% of privacy disclosure compared to baseline algorithms. Meanwhile, the
caching performance of ECs is only slightly affected