Database Reference
In-Depth Information
Figure 2.7 A cloaked region for 10-anonymity.
is, the cloaked region is likely larger. Moreover, the position accuracy varies in
time and space based on the distribution of people in space, that is, if individuals
are sparse then the cloaked regions are larger.
Location Privacy
Unlike identity privacy, location privacy aims at protecting the position informa-
tion. The protection strategy is to transmit a position that is somewhat different
in the content or in the form from the actual position. In particular, the disclosed
position can be fake, cloaked, or transmitted using some cryptographic protocol.
A
fake
position is a position deliberately represented with a wrong value.
Privacy is achieved from the fact that the reported position is false. The
accuracy and the amount of privacy mainly depend on how far the reported
location is from the exact location. For example, the client requesting a
service, for example, “where is the closest restaurant?” can transmit to the
service provider a fake position in proximity of the actual position and then
properly filter out candidate answers.
Location & query
Location & query
Location-based
data server
Answer
Candidate answers
Client
Location anonymizer
Privacy-aware query processor
Figure 2.8 The Casper architecture.
