Cryptography and Coding

The IMA conferences onCryptographyandCoding arenotonly a blend of these two aspects of information theory, but a blend of mathematics and engineering and of theoretical results and applications. The papers in this book show that the1999conferencewasnoexception. Indeed,weagainsawthemathematics- derlyingcryptographyanderrorcorrectingcodingbeing appliedto otheraspects ofcommunications,andwe alsosawclassicalmathematicalconcepts nding new applications in communications theory. As usual the conference was held at the Royal Agricultural College, Cirencester, shortly before Christmas - this time 20-22 December 1999. The papers appear in this book in the order in which they were presented, grouped into sessions,eachsessionbeginning with an invited paper. Theseinvited papers were intended to re?ect the invitees¿ views on the future of their subject - or more accurately where they intended to take it. Indeed the focus of the conf- encewas thefutureofcryptographyandcoding as seenthroughtheeyes ofyoung researchers. The r st group of papers is concerned with mathematical bounds, concepts, and constructions that form a common thread running through error corre- ing coding theory, cryptography, and codes for multiple access schemes. This is followed by a group of papers from a conference session concerned with app- cations. The papers range over various topics from arithmetic coding for data compression and encryption, through image coding, biometrics for authenti- tion, and access to broadcast channels, to photographic signatures for secure identi cation. The third set of papers deals with theoretical aspects of error c- recting coding, including graph and trellis decoding, turbo codes, convolution codes and low complexity soft decision decoding of Reed Solomon codes.