Showing papers by "Carlo Blundo published in 2012"

EsPRESSo: Efficient Privacy-Preserving Evaluation of Sample Set Similarity.

Abstract: Electronic information is increasingly often shared among entities without complete mutual trust. To address related security and privacy issues, a few cryptographic techniques have emerged that support privacy-preserving information sharing and retrieval. One interesting open problem in this context involves two parties that need to assess the similarity of their datasets, but are reluctant to disclose their actual content. This paper presents an efficient and provably-secure construction supporting the privacy-preserving evaluation of sample set similarity, where similarity is measured as the Jaccard index. We present two protocols: the first securely computes the Jaccard similarity of two sets, and the second approximates it, using MinHash techniques, with lower complexities. We show that our novel protocols are attractive in many compelling applications, including document/multimedia similarity, biometric authentication and genetic tests. In the process, we demonstrate that our constructions are appreciably more efficient than prior work.

Constrained Role Mining

Abstract: Role Based Access Control (RBAC) is a very popular access control model, for long time investigated and widely deployed in the security architecture of different enterprises. To implement RBAC, roles have to be firstly identified within the considered organization. Usually the process of (automatically) defining the roles in a bottom up way, starting from the permissions assigned to each user, is called {\it role mining}. In literature, the role mining problem has been formally analyzed and several techniques have been proposed in order to obtain a set of valid roles. Recently, the problem of defining different kind of constraints on the number and the size of the roles included in the resulting role set has been addressed. In this paper we provide a formal definition of the role mining problem under the cardinality constraint, i.e. restricting the maximum number of permissions that can be included in a role. We discuss formally the computational complexity of the problem and propose a novel heuristic. Furthermore we present experimental results obtained after the application of the proposed heuristic on both real and synthetic datasets, and compare the resulting performance to previous proposals

Constrained Role Mining

Abstract: Role Based Access Control (RBAC) is a very popular access control model, for a long time investigated and widely deployed in the security architecture of different enterprises. To implement RBAC, roles have to be firstly identified within the considered organization. Usually the process of (automatically) defining the roles in a bottom up way, starting from the permissions assigned to each user, is called role mining. In literature, the role mining problem has been formally analyzed and several techniques have been proposed in order to obtain a set of valid roles.