CRYPTO 2007, the 27th Annual International Cryptology Conference, was sponsored by the International Association for Cryptologic Research (IACR) in cooperation with the IEEE Computer Society Technical Committee on Security and Privacy, and the Computer Science Department of the University of California at Santa Barbara. The conference was held in Santa Barbara, California, August 19-23 2007. CRYPTO 2007 was chaired by Markus Jakobsson, and I had the privilege of serving as the Program Chair.

The conference received 186 submissions. Each paper was assigned at least 3 reviewers, while submissions co-authored by program committee members were reviewed by at least 5 people. After 11 weeks of discussion and deliberation, the Program Committee, aided by reports from over 148 external reviewers, selected 33 papers for presentation. The authors of accepted papers had four weeks to prepare final versions for these proceedings. These revised papers were not subject to editorial review and the authors bear full responsibility for their contents.

The committee identified the following three papers as the best papers: "Cryptography with constant input locality" by Benny Applebaum, Yuval Ishai and Eyal Kushilevitz; "Practical cryptanalysis of SFLASH" by Vivien Dubois, Pierre-Alain Fouque, Adi Shamir and Jacques Stern; and "Finding small roots of bivariate integer polynomial equations: A direct approach" by Jean-Sébastien Coron. The authors of these papers received invitations to submit full versions to the Journal of Cryptology. After a close vote, the committee selected Benny Applebaum, Yuval Ishai and Eyal Kushilevitz, the authors of the first paper, as recipients of the Best Paper Award.

The conference featured invited lectures by Ross Anderson and Paul Kocher. Ross Anderson's paper "Information security economics -- and beyond" has been included in these proceedings.

There are many people who contributed to the success of CRYPTO 2007. I would like the thank the many authors from around the world for submitting their papers. I am deeply grateful to the program committee for their hard work, enthusiasm, and conscientious efforts to ensure that each paper received a thorough and fair review. Thanks also to the external reviewers, listed on the following pages, for contributing their time and expertise. It was a pleasure working with Markus Jakobsson and the staff at Springer. I am grateful to Andy Clark, Cynthia Dwork, Arjen Lenstra and Bart Preneel for their advice. Finally, I would like to thank Dan Bernstein for organizing a lively Rump Session, and Shai Halevi for developing and maintaining his most useful Web Submission and Review Software.