k-ANONYMITY: A MODEL FOR PROTECTING PRIVACY
Abstract
Consider a data holder, such as a hospital or a bank, that has a privately held collection of person-specific, field structured data. Suppose the data holder wants to share a version of the data with researchers. How can a data holder release a version of its private data with scientific guarantees that the individuals who are the subjects of the data cannot be re-identified while the data remain practically useful? The solution provided in this paper includes a formal protection model named k-anonymity and a set of accompanying policies for deployment. A release provides k-anonymity protection if the information for each person contained in the release cannot be distinguished from at least k-1 individuals whose information also appears in the release. This paper also examines re-identification attacks that can be realized on releases that adhere to k-anonymity unless accompanying policies are respected. The k-anonymity protection model is important because it forms the basis on which the real-world systems known as Datafly, μ-Argus and k-Similar provide guarantees of privacy protection.
This paper significantly amends and substantially expands the earlier paper "Protecting privacy when disclosing information: k-anonymity and its enforcement through generalization and suppression" (with Samarati) submitted to IEEE Security and Privacy 1998, and extends parts of my Ph.D. thesis "Computational Disclosure Control: A primer on data privacy protection" at the Massachusetts Institute Technology 2001.
