Secured histories for presence systems


As sensors become ever more prevalent, more and
more information will be collected about each of us. A longterm
research question is how best to support beneficial uses
while preserving individual privacy. Presence systems are an
emerging class of applications that support collaboration. These
systems leverage pervasive sensors to estimate end-user location,
activities, and available communication channels. Because such
presence data are sensitive, to achieve wide-spread adoption,
sharing models must reflect the privacy and sharing preferences
of the users. To reflect users’ collaborative relationships and
sharing desires, we introduce CollaPSE security in which an
individual has full access to her own data, a third party processes
the data without learning anything about the data values, and
users higher up in the hierarchy learn only statistical information
about the employees under them. We describe simple schemes
that efficiently realize CollaPSE security for time series data.
We implemented these protocols using readily available cryptographic
functions, and integrated the protocols with FXPAL’s
MyUnity presence system.