The10thintheseriesofIMAConferencesonCryptographyandCodingwasheld at the RoyalAgricultural College, Cirencester, during 19-21 December 2005. As usual, the venue provided a relaxed and informal atmosphere for attendees to discuss work and listen to the collection of talks. The program consisted of four invited talks and 26 contributed talks. The invitedtalkswheregivenbyTuviEtzion,UeliMaurer,AlfredMenezesandAmin Shokrollahi, and three of these invited talks appear as papers in this volume. Special thanks must go to these four speakers as they helped to set the tone, by coveringall the areasthe meeting aimed to cover,from cryptographythrough to coding. In addition the best speakers are often the hardest to persuade to come to a meeting, as they are usually the most busy. We therefore feel privileged to have had a meeting with four such distinguished speakers. The contributed talks were selected from 94 submissions. This is nearly twice thenumberofsubmissionsforthepreviousmeetingin2003.Thisisanindication of the strength of the subject and the interest in the IMA series of meetings as a venue to present new work. The contributed talks ranged over a wide number of areas, including information theory, coding theory, number theory and as- metric and symmetric cryptography. Subtopics included a number of current "hot topics," such as algebraic cryptanalysis and cryptographic systems based on bilinear pairings. Assembling the conference program and these proceedings required the help of a large number of individuals. I would like to thank them all here.