Researchers and practitioners of cryptography and information security are constantly challenged to respond to new attacks and threats to information systems. Authentication Codes and Combinatorial Designs presents new findings and original work on perfect authentication codes characterized in terms of combinatorial designs, namely strong partially balanced designs (SPBD). Beginning with examples illustrating the concepts of authentication schemes and combinatorial designs, the book considers the probability of successful deceptions followed by schemes involving three and four participants, respectively. From this point, the author constructs the perfect authentication schemes and explores encoding rules for such schemes in some special cases. Using rational normal curves in projective spaces over finite fields, the author constructs a new family of SPBD. He then presents some established combinatorial designs that can be used to construct perfect schemes, such as t-designs, orthogonal arrays of index unity, and designs constructed by finite geometry. The book concludes by studying definitions of perfect secrecy, properties of perfectly secure schemes, and constructions of perfect secrecy schemes with and without authentication. Supplying an appendix of construction schemes for authentication and secrecy schemes, Authentication Codes and Combinatorial Designs points to new applications of combinatorial designs in cryptography.

Chinese Remainder Theorem, CRT, is one of the jewels of mathematics. It is a perfect combination of beauty and utility or, in the words of Horace, omne tulit punctum qui miscuit utile dulci. Known already for ages, CRT continues to present itself in new contexts and open vistas for new types of applications. So far, its usefulness has been obvious within the realm of "three C's". Computing was its original field of application, and continues to be important as regards various aspects of algorithmics and modular computations. Theory of codes and cryptography are two more recent fields of application.This book tells about CRT, its background and philosophy, history, generalizations and, most importantly, its applications. The book is self-contained. This means that no factual knowledge is assumed on the part of the reader. We even provide brief tutorials on relevant subjects, algebra and information theory. However, some mathematical maturity is surely a prerequisite, as our presentation is at an advanced undergraduate or beginning graduate level. We have tried to make the exposition innovative, many of the individual results being new. We will return to this matter, as well as to the interdependence of the various parts of the book, at the end of the Introduction.A special course about CRT can be based on the book. The individual chapters are largely independent and, consequently, the book can be used as supplementary material for courses in algorithmics, coding theory, cryptography or theory of computing. Of course, the book is also a reference for matters dealing with CRT.

ASIACRYPT'98, the international conference covering all aspects of theory and application of cryptology and information security, is being held at Beijing Friendship Hotel from October 18 to 22. This is the fourth of the Asiacrypt conferences. ASIACRYPT'98 is sponsored by the State Key Laboratory of Information Security (SKLOIS), University of Science and Technology of China (USTC), and the Asiacrypt Steering Committee (ASC), in cooperation with the International Association for Cryptology Research (IACR). The 16-member Program Committee organized the scientific program and considered 118 submissions. Of these, 32 were accepted for presentation. The authors' affiliations of the 118 submissions and the 32 accepted papers range over 18 and 13 countries or regions, respectively. The submitted version of each paper was sent to all members of the Program Committee and was extensively examined by at least three committee members and/or outside experts. The review process was rigorously blinded and the anonymity of each submission are maintained until the selection was completed. We followed the traditional policy that each member of the Program Committee could be an author of at most one accepted paper. These proceedings contain the revised versions of the 32 contributed talks as well as a short note written by one invited speaker. Comments from the Program Committee were taken into account in the revisions. However, the authors (not the committee) bear full responsibility for the contents of their papers.

The Third SKLOIS Conference on Information Security and Cryptology (- scrypt2007)wasorganizedbytheStateKeyLaboratoryofInformationSecurity of the Chinese Academy of Sciences in cooperation with Qinhai University for Nationalities. This international conference was held in Xining, Qinhai Province of China, and was sponsored by the Institute of Software, the Chinese Academy of Sciences, the Graduate University of the Chinese Academy of Sciences and the National Natural Science Foundations of China. By now, Inscrypt (the International SKLOIS Conference on Information - curity and Cryptology) has become a tradition, and it is, in fact, a leading event in this area, which takes place annually in China. We are pleased with the continuous support by authors, committee members, reviewers, sponsors and organizers. Indeed, the research areas covered by Inscrypt are important, since modern computing (including communication infrastructures and applications) requires increased security, trust, safety and reliability. This need has motivated the research community worldwide to produce important fundamental, exp- imental and applied work in the wide areas of cryptography and information securityresearchin recent years.Accordingly, the programof Inscrypt 2007c- ered numerous ?elds of research within these general areas