This book constitutes the refereed proceedings of the Third International Information Security Practice and Experience Conference, ISPEC 2007, held in Hong Kong, China in May 2007.

The 24 revised full papers presented together with 2 invited papers were carefully reviewed and selected from 135 submissions. The papers are organized in topical sections on cryptanalysis, signatures, network security and security management, privacy and applications, cryptographic algorithms and implementations, authentication and key management, as well as cryptosystems.

TheseventhinternationalconferenceonCryptologyandNetworkSecurity(CANS 2008)washeld at HKU Town Center, Hong Kong, China, during December 2-4, 2008. The conference was organized by the Department of Computer Science, theUniversityofHongKong, andwasfullysupportedbytheCenterforInfor- tion Security and Cryptography at the University of Hong Kong, the Cyberport Institute of Hong Kong at the University of Hong Kong and the Department of Computer Science at the City University of Hong Kong. The goal of CANS is to promote research on all aspects of network security, as well as to build a bridge between research on cryptography and network security. Previous CANS conferences have been held in Taipei, Taiwan (2001), SanFrancisco, USA (2002), Miami, USA (2003), Xiamen, China (2005), Suzhou, China (2006), and Singapore (2007). The conference proceedings of recent years were published by Springer in the Lecture Notes in Computer Science series. The Program Committee received 73 submissions, and accepted 27 papers for presentation. The ?nal versions of the accepted papers, which the authors ?nalized on the basis of comments from the reviewers, were included in the proceedings. The reviewing process took nine weeks; each paper was carefully evaluated by at least three members from the Program Committee. The in- vidual reviewing phase was followed by a Web-based discussion. Based on the comments and scores given by reviewers, the ?nal decisions on acceptance were made. We appreciate the hard work of the members of the Program Committee and the external referees who gave many hours of their valuabl