The 1st International Conference on "Applied Cryptography and Network Se- rity" (ACNS 2003) was sponsored and organized by ICISA (International C- munications and Information Security Association), in cooperation with MiAn Pte. Ltd. and the Kunming government. It was held in Kunming, China in - tober 2003. The conference proceedings was published as Volume 2846 of the Lecture Notes in Computer Science (LNCS) series of Springer-Verlag. The conference received 191 submissions, from 24 countries and regions; 32 of these papers were accepted, representing 15 countries and regions (acceptance rate of 16.75%). In this volume you will ?nd the revised versions of the - cepted papers that were presented at the conference. In addition to the main track of presentations of accepted papers, an additional track was held in the conference where presentations of an industrial and technical nature were given. These presentations were also carefully selected from a large set of presentation proposals. This new international conference series is the result of the vision of Dr. Yongfei Han.The conference concentrates on current developments that advance the - eas of applied cryptography and its application to systems and network security. The goal is to represent both academic research works and developments in - dustrial and technical frontiers. We thank Dr. Han for initiating this conference and for serving as its General Chair.