These are the proceedings of EUROCRYPT 2003, the 22nd annual EURO- CRYPT conference. The conference was sponsored by the IACR, the Internat- nal Association for Cryptologic Research,www.iacr.org, this year in coope- tion with the Institute of Mathematics and Cryptology, Faculty of Cybernetics, Military University of Technology, Warsaw, Poland. The General Chair, Jerzy Gawinecki, was responsible for the local organization, and the conference re- stration was handled by the IACR secretariat at the University of California, Santa Barbara, USA. A total of 37 papers were accepted for presentation at the conference, out of 156 papers submitted (of which one was withdrawn by the authors shortly after the submission deadline). These proceedings contain revised versions of the accepted papers. In addition two invited talks were given: the ?rst was given by Kris Gaj and Arkadiusz Orlowski, entitled "Facts and Myths of Enigma: Breaking Stereotypes." The second invited talk was given by Jacques Stern - titled "Why Provable Security Matters?" The conference program also included arumpsession,chairedbyStanis lawJarecki,whichfeaturedshortinformaltalks on recent results.