Recently, several techniques have been proposed to protect
the user location
privacy for location-based services in the Euclidean space
. Applying these techniques
directly to the road network environment would lead to priva
cy leakage and inefficient
query processing. In this paper, we propose a new location an
onymization algorithm
that is designed specifically for the road network environme
nt. Our algorithm relies
on the commonly used concept of spatial cloaking, where a use
r location is cloaked
into a set of connected road segments of a minimum total lengt
h
L
including at least
K
users. Our algorithm is “query-aware” as it takes into accou
nt the query execution
cost at a database server and the query quality, i.e., the num
ber of objects returned to
users by the database server, during the location anonymiza
tion process. In particular,
we develop a new cost function that balances between the quer
y execution cost and
the query quality. Then, we introduce two versions of our alg
orithm, namely,
pure
greedy
and
randomized greedy
, that aim to minimize the developed cost function and
satisfy the user specified privacy requirements. To accommo
date intervals with a high
workload, we introduce a
shared execution paradigm
that boosts the scalability of our
location anonymization algorithm and the database server t
o support large numbers
of queries received in a short time period. Extensive experi
mental results show tha