The number of people on social networks has grown exponentially. Users share
very large volumes of personal informations and content every days. This
content could be tagged with geo-spatial and temporal coordinates that may be
considered sensitive for some users. While there is clearly a demand for users
to share this information with each other, there is also substantial demand for
greater control over the conditions under which their information is shared.
Content published in a geo-aware social networks (GeoSN) often involves
multiple users and it is often accessible to multiple users, without the
publisher being aware of the privacy preferences of those users. This makes
difficult for GeoSN users to control which information about them is available
and to whom it is available. Thus, the lack of means to protect users privacy
scares people bothered about privacy issues. This paper addresses a particular
privacy threats that occur in GeoSNs: the Co-location privacy threat. It
concerns the availability of information about the presence of multiple users
in a same locations at given times, against their will. The challenge addressed
is that of supporting privacy while still enabling useful services.Comment: 10 pages, 5 figure