On Anonymization of Multi-graphs

The problem of privacy-preserving data mining has attracted considerable attention in recent years because of increasing concerns about the privacy of the underlying data. In recent years, an important data domain which has emerged is that of graphs and structured data. Many data sets such as XML data, transportation networks, traffic in IP networks, social networks and hierarchically structured data are naturally represented as graphs. Existing work on graph privacy has focussed on the problem of anonymizing nodes or edges of a single graph, in which the identity is assumed to be associated with individual nodes. In this paper, we examine the more complex case, where we have a collection of graphs, and the identity is associated with individual graphs rather than nodes or edges. In such cases, the problem of identity anonymization is extremely difficult, since we need to not only anonymize the labels on the nodes, but also the underlying global structural information. In such cases, both the global and local structural information can be a challenge to the anonymization process, since any combination of such information can be used in order to de-identify the underlying graphs. In order to achieve this goal, we will create synthesized representations of the underlying graphs based on aggregate structural analytics of the collection of graphs. The synthesized graphs retain the properties of the original data while satisfying the k-anonymity requirement. Our experimental results show that the synthesized graphs maintain a high level of structural information and compatible classification accuracies with the original data.