Remarks on Periods and Colorings in Graphs

Connectivity of an undirected graph is revisited by means of its reduced graphs and related to its orientations. Sufficient conditions for chromatic numbers are obtained from periods of strong orientations

Sorting Out Signature Schemes

. Digital signature schemes are a fundamental tool for secure distributed systems. A formal definition of digital signature schemes is important, so that there is a clear interface between designers and users of such schemes. A definition that seemed final was given by Goldwasser, Micali, and Rivest in 1988. Recently, however, several signature schemes with new security properties have been presented. Most of them exist in several variants, and some of them pay for the new properties with restrictions in other respects. These new properties need definitions and some classification. Unfortunately, however, none of the new schemes is covered by the definition mentioned above. Hence the new properties cannot be defined as additions, but each new type of scheme needs a new definition from scratch. This is unsatisfactory. This paper presents a general definition of digital signature schemes that covers all known schemes, and hopefully all that might be invented in future. Additional propert..

Specification of Systems: Theory in Search for Practice - Summary of a Workshop

ion for developing Reactive Systems : : : : : : : : : : : : : : : : : : : : : : : 18 Steven Klusener, CWI: Verification of an Audio protocol : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 19 Hans Hook, SICS About Integration of Formal Description Techniques and Systems Development Processes : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 20 List of participants : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 21 iv Foreword Specification and design of distributed computer systems is a complex and error-prone affair, and large efforts are therefore made on development of appropriate design methods. But there is a gap between theory and practice: the benefits of theoretical support are not being realized in practice, and conversely the theoretic developments do..