Databases Reference
In-Depth Information
the LM. The returned response from the LM to the ACE is assumed to be
a boolean value with associated a relevance value
R
Eval
that characterizes
the accuracy.
R
Priv
by considering the obfuscated
area generated by the LM and the LBAC predicate. The meaning of
R
Eval
is derived from
R
Eval
is the reliability of the predicate evaluation, which depends on the accuracy
R
Priv
of the obfuscated location information. The LM calculates
R
Eval
as follows:
Area
Priv∩LBAC
Area
Priv
R
Eval
=
·R
Priv
(7)
Area
Priv
∩
LBAC
where the scalar factor
Area
Priv
depends on the degree of overlap-
ping between the areas resulting by the application of the obfuscation tech-
niques to the location measurement of the user and the area specified by
the LBAC predicate (i.e.,
Area
Priv∩LBAC
). Again,
R
LBAC
≤R
Eval
must
hold.
Both solutions are viable, although well-suited for different sets of require-
ments. On the one side, the ACE Evaluation provides a clear separation be-
tween business-oriented components (i.e., ACE and Business Application) and
location services (i.e., LM and LP). In addition, ACE Evaluation assures that
the LM never deals with application-dependent predicates and the ACE never
releases information about its access control policies. On the other side, LM
Evaluation avoids releasing location information to the ACE. In this setting,
location information is always managed by LM that becomes the only trusted
component of the architecture with regard to location privacy.
6 Conclusions
Information regarding physical locations of users is rapidly becoming easily
available for processing by online and mobile location-based services. Com-
bined with novel application opportunities, however, threats to personal pri-
vacy are gaining special prominence, as witnessed by recent security incidents
targeting privacy of individuals. This chapter has presented the main tech-
niques aimed at protecting location privacy. The chapter has also described
a privacy-aware LBAC architecture that integrates users privacy preferences,
obfuscation techniques for location privacy protection, and privacy-enhanced
location-based access control.
Acknowledgments
This work was partially supported by the European Union within the PRIME
Project in the FP6/IST Programme under contract IST-2002-507591, by the
Italian Ministry of Research Fund for Basic Research (FIRB) under project
RBNE05FKZ2 and by the Italian MIUR under project MAPS.
