C. Ding – författare

This book is almost entirely concerned with stream ciphers, concentrating on a particular mathematical model for such ciphers which are called additive natural stream ciphers. These ciphers use a natural sequence generator to produce a periodic keystream. Full definitions of these concepts are given in Chapter 2.This book focuses on keystream sequences which can be analysed using number theory. It turns out that a great deal of information can be deducted about the cryptographic properties of many classes of sequences by applying the terminology and theorems of number theory. These connections can be explicitly made by describing three kinds of bridges between stream ciphering problems and number theory problems. A detailed summary of these ideas is given in the introductory Chapter 1.Many results in the book are new, and over seventy percent of these results described in this book are based on recent research results.

This volume contains the refereed proceedings of the International Conference on Sequences and Their Applications which was held at the River View Ho- tel in Singapore during December 14-17, 1998. The program of this conference was arranged by a committee consisting of Claude Carlet (University of Caen) , Agnes Chan (Northeastern University), Cunsheng Ding (National University of Singapore, co-chair), Dieter Gollmann (Microsoft Research), Tor Helleseth (Uni- versity of Bergen, co-chair), Kyoki Imamura (Kyushu Institute of Technology), Andrew Klapper (University of Kentucky), Vijay Kumar (University of Southern California), Siu Lun Ma (National University of Singapore), Harald Niederreiter (A ustrian Academy of Sciences, co-chair), Dilip Sarwate (University of Illinois at Urbana-Champaign), Hans Schotten (Aachen University of Technology), Jeffrey Shallit (University of Waterloo), Neil Sloane (AT&T Shannon Lab), and Aimo Tietiivajnen (University of Turku). The local organization was in the hands of Cunsheng Ding, Kwok Van Lam (chair), Sjauntele Lau, and Sew Kiok Toh, all of the National University of Singapore.The idea for the conference grew out of the recognition that sequences in discrete structures like the ring of integers, residue class rings of the integers, and finite fields have found many important applications in modern information and communication technologies. Among these applications we mention cryp- tographic schemes, ranging systems, spread spectrum communication systems, multi-terminal system identification, code-division mUltiple-access communica- tion systems, global positioning systems, software testing, circuit testing, and computer simulation. There are also connections between sequences in discrete structures and error-correcting codes.