The growing popularity of location-based systems, allowing unknown/untrusted
servers to easily collect huge amounts of information regarding users'
location, has recently started raising serious privacy concerns. In this paper
we study geo-indistinguishability, a formal notion of privacy for
location-based systems that protects the user's exact location, while allowing
approximate information - typically needed to obtain a certain desired service
- to be released. Our privacy definition formalizes the intuitive notion of
protecting the user's location within a radius r with a level of privacy that
depends on r, and corresponds to a generalized version of the well-known
concept of differential privacy. Furthermore, we present a perturbation
technique for achieving geo-indistinguishability by adding controlled random
noise to the user's location. We demonstrate the applicability of our technique
on a LBS application. Finally, we compare our mechanism with other ones in the
literature. It turns our that our mechanism offers the best privacy guarantees,
for the same utility, among all those which do not depend on the prior.

本文介绍了基于位置系统中用户隐私问题，提出了一种新的保障用户位置隐私的定义，并通过在用户位置中添加控制随机噪声的扰动技术来实现此目的，并与其他文献中的保护机制进行比较，结果表明我们的机制在不依赖于先验知识的情况下，为用户提供了最好的隐私保障。