Location Privacy Protection Through Obfuscation

Introduction. Technical improvements of detection and transmission of location information, together with the widespread adoption of mobile communication devices and location-based services for business, social or informational purposes, are increasing the privacy concerns. Better, more elaborated solutions are necessary to provide users (Rule Makers, as they are called in geopriv) the possibility to express privacy policies and technical means to implement them. This is easier said than done. Some important scenarios can be dealt with, in a satisfactory way using Pseudonymor Anonymity-based techniques, because the real identity of the individual is irrelevant for the service. If necessary, the individual and the recipient of the location information can run a “pseudonym-agreement protocol”, similar to some unauthenticated key agreements. But there is a large class of situations in which the identity of the individual to be located is to be explicitly disclosed (or known) to the recipient. Let us suppose a user wants to make his position available via a presence service or within an online social forum to his contacts. Then, he will prefer to disclose his location with a high precision to close friends and with a low ones to others. In some cases, he may wish to disclose his location within 10 or within 100 km. Further, let us assume, he does not want to lie about his location, and the algorithm should not force him to do so.