An efficient hash-based algorithm for minimal k-anonymity

Abstract

A number of organizations publish microdata for pur- poses such as public health and demographic research. Although attributes of microdata that clearly iden- tify individuals, such as name and medical care card number, are generally removed, these databases can sometimes be joined with other public databases on attributes such as Zip code, Gender and Age to re- identify individuals who were supposed to remain anonymous. "Linking" attacks are made easier by the availability of other complementary databases over the Internet. k-anonymity is a technique that prevents "link- ing" attacks by generalizing and/or suppressing por- tions of the released microdata so that no individual can be uniquely distinguished from a group of size k. In this paper, we investigate a practical model of k- anonymity, called full-domain generalization. We ex- amine the issue of computing minimal k-anonymous table based on the definition of minimality described by Samarati. We introduce the hash-based technique previously used in mining associate rules and present an efficient hash-based algorithm to find the minimal k-anonymous table, which improves the previous bi- nary search algorithm first proposed by Samarati.