TCC 2007, the Fourth Theory of Cryptography Conference, was held in Amsterdam, the Netherlands, from February 21 to 24, 2007, at Trippenhuis, the headquarters of the Royal Dutch Academy of Arts and Sciences (KNAW). TCC 2007 was sponsored by the International Association for Cryptologic Research (IACR) and was organized in cooperation with the Cryptology and Information Security Group at CWI, Amsterdam; the Mathematical Institute, Leiden University; and DIAMANT, the Dutch national mathematics cluster for discrete interactive and algorithmic algebra and number theory. The general chair of the conference was Ronald Cramer.
The conference received 118 submissions, of which the Program Committee selected 31 for presentation at the conference. These proceedings consist of revised versions of those 31 papers. The revisions were not reviewed, and the authors bear full responsibility for the contents of their papers. The Best Student Paper Award was given to Saurabh Panjwani for his paper "Tackling Adaptive Corruptions in Multicast Encryption Protocols."
The conference program also included a tutorial on "Quantum Cryptography," given by Renato Renner, and a special event on the "The Assumptions for Cryptography," consisting of a few short talks and a panel discussion. In addition, the Program Committee decided to augment the traditional rump session to include short informal presentations of not only new results, but also open problems and future research directions.
One of the things that has made my job as program chair a pleasure is the wonderful dedication our community has to success of TCC. I am grateful to the many people who have contributed to the organization and content of the conference. First and foremost, this includes the authors of all submitted papers, whose research efforts are the raison d'etre for TCC. I am also indebted to my extremely dedicated Program Committee. They were faced with a larger than expected workload due to a jump in the number of submissions, yet they carried out the review process with extraordinary thoroughness and care for the high standards and integrity of TCC. I also thank the many external reviewers who assisted the Program Committee in its work.
I thank the Steering Committee of TCC for entrusting me with this responsibility, and its chair, Oded Goldreich, for being available as a source of wisdom throughout the process. I also benefited from the experience and advice of the past TCC chairs, Moni Naor, Joe Kilian, Tal Rabin, and Shai Halevi. I am especially indebted to Shai, who wrote a wonderful software package that I used for handling the submissions, the PC discussions, and these proceedings and provided rapid-response customization and technical support throughout.
I am very grateful to Ronald Cramer, TCC 2007 General Chair; his Co-chairs Serge Fehr, Dennis Hofheinz, and Eike Kiltz; and Wilmy van Ojik, the CWI Conference Organizer, for all the work they have put into hosting the conference and managing its logistics. Thanks also to Microsoft for a generous donation that supported the conference in various ways, including stipends to help students attend. I appreciate the assistance provided by the Springer LNCS editorial staff, including Alfred Hofmann, Frank Holzwarth, Anna Kramer, and Erika Siebert-Cole, in assembling these proceedings. Finally, I thank Carol Harlow for the administrative help she provided here at Harvard.
TCC 2007 would not have been possible without the efforts of all the people I have mentioned here, as well as the many that I have surely forgotten (to whom I apologize).