Date Added: Mar 2010
Storing and sharing databases in the cloud of computers raise serious concern of individual privacy. The authors consider two kinds of privacy risk: presence leakage, by which the attackers can explicitly identify individuals in or not in the database, and association leakage, by which the attackers can unambiguously associate individuals with sensitive information. However, the existing privacy-preserving data sharing techniques either fail to protect the presence privacy or incur considerable amounts of information loss. This paper proposes a novel technique, Ambiguity, to protect both presence privacy and association privacy with low information loss. The authors formally define the privacy model and quantify the privacy guarantee of Ambiguity against both presence leakage and association leakage.