Search

In this paper, a novel threshold multi-group-secret sharing scheme is proposed based on Chan et al.'s scheme. Multiple groups of secrets are packed into a group of large secrets by using the Chinese Remain Theorem, and then shared by constructing a secret polynomial such that its coefficients are those large secrets. In the proposed scheme, the secret distribution procedure is needed only once to share multiple groups of secrets, which reduces the amount of computation largely. Moreover, each group of secrets has a different threshold access structure and includes a distinct number of secrets. Analysis results show that the proposed scheme needs fewer public values and is higher in efficiency and easier in implementation than existing schemes, especially for sharing many groups of secrets, which makes it more practical in practice. [ABSTRACT FROM AUTHOR]

Untraceability and unreuseability are essential security properties for electronic cash protocols. Many protocols have been proposed to meet these two properties. However, most of them have not been formally proved to be untraceable and unreuseable. In this paper we propose to use the applied pi calculus as a framework for describing and analyzing electronic cash protocols, and we analyze Ferguson's electronic cash protocol as a case study. We believe that this approach is suitable for many different electronic cash protocols. [ABSTRACT FROM AUTHOR]

A new secret sharing scheme with general access structures was proposed, which is based on Shamir's secret sharing scheme and the discrete logarithm problem. In this scheme, the dealer need not send any secret information to participants. And the shared secret, the participant set and the access structure can be changed dynamically without updating any participant's secret shadow. The degree of the used Lagrange interpolation polynomial is only one, which makes the computational complexity of the proposed scheme very low. The proposed scheme has advantages over the existing schemes and thus provides great capabilities for many applications. [ABSTRACT FROM AUTHOR]

We address the problem of model checking hybrid systems which exhibit nontrivial discrete behavior and thus cannot be treated by considering the discrete states one by one, as most currently available verification tools do. Our procedure relies on a deep integration of several techniques and tools. An extension of AND-Inverter-Graphs (AIGs) with first-order constraints serves as a compact representation format for sets of configurations which are composed of continuous regions and discrete states. Boolean reasoning on the AIGs is complemented by first-order reasoning in various forms and on various levels. These include implication checks for simple constraints, test vector generation for fast inequality checks of boolean combinations of constraints, and an exact subsumption check for representations of two configurations. These techniques are integrated within a model checker for universal CTL. Technically, it deals with discrete-time hybrid systems with linear differentials. The paper presents the approach, its prototype implementation, and first experimental data. [ABSTRACT FROM AUTHOR]

We show that timed branching bisimilarity as defined by van der Zwaag [14] and Baeten & Middelburg [2] is not an equivalence relation, in case of a dense time domain. We propose an adaptation based on van der Zwaag's definition, and prove that the resulting timed branching bisimilarity is an equivalence indeed. Furthermore, we prove that in case of a discrete time domain, van der Zwaag's definition and our adaptation coincide. [ABSTRACT FROM AUTHOR]