The 4th International Conference on Cryptology and Network Security (CANS 2005) was held in Xiamen, Fujian Province, China, December 14-16, 2005. The conference was sponsored by the Fujian Normal University and Fujian Digital Certi?cate Authority Co. Ltd and was organized in cooperation with the Int- national Association for Cryptologic Research (IACR). The ?rst International Workshop on Cryptology and Network Security was in Taipei, Taiwan, 2001. The second one was in San Francisco, California, USA, September 26-28, 2002, and the third in Miami, Florida, USA, September 24-26, 2003. CANS 2005 was the ?rst CANS with proceedings published in the Lecture Notes in Computer Science series by Springer. The Program Committee received 118 submissions, and accepted 28 papers from which 1 withdrew and thus 27 papers were included in the proceedings. The reviewing process took eight weeks, each paper was carefully evaluated by at least three members from the Program Committee. We appreciate the hard work of the members of the ProgramCommittee and external referees who gave manyhoursoftheir valuabletime.Thanksto CarlEllison,GoceJakimoski,Bart Preneel, Yongge Wang, Christopher Wolf and Shouhuai Xu, who acted as the shepherds of 6 papers included in the proceedings. In addition to the contributed papers, there were two invited talks: Wenbo Mao spoke on "Research Issues in Network Security" - a practical viewpoint; and Matt Franklin on "Research Issues in Network Security" - a foundations viewpoint.

The CRYPTO '94 conference is sponsored by the International Association for Cryptologic Research (IACR), in co-operation with the IEEE Computer Society Technical Committee on Security and Privacy. It has taken place at the Univ- sity of California, Santa Barbara, from August 21-25,1994. This is the fourteenth annual CRYPTO conference, all of which have been held at UCSB. This is the first time that proceedings are available at the conference. The General Chair, Jimmy R. Upton has been responsible for local organization, registration, etc. There were 114 submitted papers which were considered by the Program Committee. Of these, 1 was withdrawn and 38 were selected for the proce- ings. There are also 3 invited talks. Two of these are on aspects of cryptog- phy in the commercial world. The one on hardware aspects will be presented by David Maher (AT&T), the one on software aspects by Joseph Pato (Hewlett- Packard). There will also be a panel discussion on "Securing an Electronic World: Are We Ready?" The panel members will be: Ross Anderson, Bob Blakley, Matt Blaze, George Davida, Yvo Desmedt (moderator), Whitfield Diffie, Joan Feig- baum, Blake Greenlee, Martin Hellman, David Maher, Miles Smid. The topic of the panel will be introduced by the invited talk of Whitfield Diffie on "Securing the Information Highway. " These proceedings contain revised versions of the 38 contributed talks. Each i paper was sent to at least 3 members of the program committee for comments.