Fred Piper has been a Professor of Mathematics at the University of London since 1975 and has worked in security since 1979. In 1985 he formed a company, Codes and Ciphers Ltd., which offers consultancy advice in all aspects of information security.He has lectured worldwide on a wide range of topics in information security, both academically and comercially. Sean Murphy is currently a Reader in the Information Security Group. His research interests centre on cryptology, especially encryption algorithms. He published some of the early papers on differential cryptanalysis, and has written papers on a variety of cryptographic algorithms such as DES, FEAL, IDEA, SAFER and Twofish.