Catálogo de publicaciones - libros

A choreography specifies the interactions between the resources of multiple collaborating parties at design time. The runtime management of authorization policies in order to support such a specification is however tedious for administrators to manually handle. By compiling the choreography into enhanced authorization policies, we are able to automatically derive the minimal authorizations required for collaboration, as well as enable and disable the authorizations in a just-in-time manner that matches the control flow described in the choreography. We have evaluated the advantage of this utility in a collaborative engineering scenario.

Privacy protection has become one of the most important issues in the information era. Consequently, many protocols have been developed to achieve the goal of accomplishing a computational task cooperatively without revealing the participants’ private data. Practical protocols, however, do not guarantee perfect privacy protection, as some degree of privacy leakage is allowed so that resources can be used efficiently, e.g., the number of random bits required and the computation time. A metric for measuring the degree of information leakage based on an information theoretical framework was proposed in [2]. Based on that formal framework, we present a lower bound of the scalar product problem in this paper, and show that to solve the problem without the help of a third party, approximately half the private information must be revealed. To better capture our intuition about the secrecy of various protocols, we propose two more measurements: and . The first measures how evenly the information leakage is distributed among the participants’ private inputs. The second measures the size of the smallest set an adversary could use to obtain the same ratio of leaked information that could be derived in the worst case scenario.