This book constitutes the refereed proceedings of the 6th International Conference on Cryptography and Coding held at the Institute of Mathematics and its Applications (IMA) in Cirencester, UK, in December 1997. The 35 revised full papers presented emphasize the links and commonality between the underlying mathematical bases and algorithmic foundations of cryptography, error control coding and digital signal processing devices available today. Besides classical crypto topics, other issues concerning information transmission and processing are addressed, such as multiple-access coding, image processing, synchronization and sequence design.