The ninth in the series of IMA Conferences on Cryptography and Coding was held (as ever) at the Royal Agricultural College, Cirencester, from 16–18 Dec- ber 2003. The conference’s varied programme of 4 invited and 25 contributed papers is represented in this volume. The contributed papers were selected from the 49 submissions using a - reful refereeing process. The contributed and invited papers are grouped into 5 topics: coding and applications; applications of coding in cryptography; cryp- graphy; cryptanalysis; and network security and protocols. These topic headings represent the breadth of activity in the areas of coding, cryptography and c- munications, and the rich interplay between these areas. Assemblingtheconferenceprogrammeandthisproceedingsrequiredthehelp of many individuals. I would like to record my appreciation of them here. Firstly, I would like to thank the programme committee who aided me - mensely by evaluating the submissions, providing detailed written feedback for the authors of many of the papers, and advising me at many critical points - ring the process. Their help and cooperation was essential, especially in view of the short amount of time available to conduct the reviewing task. The c- mittee this year consisted of Mike Darnell, Mick Ganley, Bahram Honary, Chris Mitchell, Matthew Parker, Nigel Smart and Mike Walker.

Table of Contents:
Coding and Applications.- Recent Developments in Array Error-Control Codes.- High Rate Convolutional Codes with Optimal Cycle Weights.- A Multifunctional Turbo-Based Receiver Using Partial Unit Memory Codes.- Commitment Capacity of Discrete Memoryless Channels.- Separating and Intersecting Properties of BCH and Kasami Codes.- Applications of Coding in Cryptography.- Analysis and Design of Modern Stream Ciphers.- Improved Fast Correlation Attack Using Low Rate Codes.- On the Covering Radius of Second Order Binary Reed-Muller Code in the Set of Resilient Boolean Functions.- Degree Optimized Resilient Boolean Functions from Maiorana-McFarland Class.- Differential Uniformity for Arrays.- Cryptography.- Uses and Abuses of Cryptography.- A Designer’s Guide to KEMs.- A General Construction of IND-CCA2 Secure Public Key Encryption.- Efficient Key Updating Signature Schemes Based on IBS.- Periodic Sequences with Maximal Linear Complexity and Almost Maximal k-Error Linear Complexity.- Cryptanalysis.- Estimates for Discrete Logarithm Computations in Finite Fields of Small Characteristic.- Resolving Large Prime(s) Variants for Discrete Logarithm Computation.- Computing the M = UU t Integer Matrix Decomposition.- Cryptanalysis of the Public Key Cryptosystem Based on the Word Problem on the Grigorchuk Groups.- More Detail for a Combined Timing and Power Attack against Implementations of RSA.- Predicting the Inversive Generator.- A Stochastical Model and Its Analysis for a Physical Random Number Generator Presented At CHES 2002.- Analysis of Double Block Length Hash Functions.- Network Security and Protocols.- Cryptography in Wireless Standards.- On the Correctness of Security Proofs for the 3GPP Confidentiality and Integrity Algorithms.- A General Attack Model on Hash-BasedClient Puzzles.- Tripartite Authenticated Key Agreement Protocols from Pairings.- Remote User Authentication Using Public Information.- Mental Poker Revisited.