I thank Sha? Goldwasser for chairing this conference and making all the necessaryarrangementsatMIT.Sha?inturnistremendouslygratefultoJoanne Talbot who coordinated the conference facilities, hotels, Web page, budgets, and the conference chair relentlessly and without a single complaint. Thank you Joanne. I thank Mihir Bellare for chairing the Steering Committee of TCC and the members of the committee (see the list in the pages that follow) for helping out with many issues concerning the conference, including the proceedings and the TCC Web-site. Finally a big thanks is due to Oded Goldreich who initiated this endeavor and pushed hard for it.Rehovot, Israel Moni Naor December 2003 Program Chair TCC 2004 VII External Referees Masayuki Abe Daniel Gottesman Jesper Buus Nielsen Luis van Ahn Jens Groth Adriana Palacio Michael Backes Shai Halevi Erez Petrank Boaz Barak Danny Harnik Benny Pinkas Amos Beimel Alejandro Hevia Tal Rabin Mihir Bellare Thomas Jakobsen Oded Regev Alexandra Boldyreva Markus Jakobsson Amit Sahai Harry Buhrman Ari Juels Jean-Pierre Seifert Christian Cachin Jonathan Katz Adam Smith Jan Camenisch Hugo Krawczyk Martijn Stam Claude Cr' epeau Eyal Kushilevitz Yael Tauman Kalai Anand Desai Yehuda Lindell Michael Waidner Yan Zong Ding Anna Lysyanskaya John Watrous Yevgeniy Dodis Tal Malkin Douglas Wikstr. om Marc Fischlin David Meyer Bogdan Warinschi Juan Garay Ashwin Nayak Stephanie Wehner Rosario Gennaro Gregory Neven Ke Yang TCC Steering Committee Mihir Bellare (Chair) UCSD, USA ? Ivan Damg? ard Arhus University, Denmark Oded Goldreich Weizmann Institute, Israel and Radcli?e Institute, USA Sha? Goldwasser MIT, USA and Weizmann Institute, Israel

This book constitutes the refereed proceedings of the 26th Annual International Conference on the Theory and Applications of Cryptographic Techniques, EUROCRYPT 2007, held in Barcelona, Spain in May 2007. The 33 revised full papers address all current foundational, theoretical and research aspects of cryptology, cryptography, and cryptanalysis as well as advanced applications.

I thank Sha? Goldwasser for chairing this conference and making all the necessaryarrangementsatMIT.Sha?inturnistremendouslygratefultoJoanne Talbot who coordinated the conference facilities, hotels, Web page, budgets, and the conference chair relentlessly and without a single complaint. Thank you Joanne. I thank Mihir Bellare for chairing the Steering Committee of TCC and the members of the committee (see the list in the pages that follow) for helping out with many issues concerning the conference, including the proceedings and the TCC Web-site. Finally a big thanks is due to Oded Goldreich who initiated this endeavor and pushed hard for it.Rehovot, Israel Moni Naor December 2003 Program Chair TCC 2004 VII External Referees Masayuki Abe Daniel Gottesman Jesper Buus Nielsen Luis van Ahn Jens Groth Adriana Palacio Michael Backes Shai Halevi Erez Petrank Boaz Barak Danny Harnik Benny Pinkas Amos Beimel Alejandro Hevia Tal Rabin Mihir Bellare Thomas Jakobsen Oded Regev Alexandra Boldyreva Markus Jakobsson Amit Sahai Harry Buhrman Ari Juels Jean-Pierre Seifert Christian Cachin Jonathan Katz Adam Smith Jan Camenisch Hugo Krawczyk Martijn Stam Claude Cr' epeau Eyal Kushilevitz Yael Tauman Kalai Anand Desai Yehuda Lindell Michael Waidner Yan Zong Ding Anna Lysyanskaya John Watrous Yevgeniy Dodis Tal Malkin Douglas Wikstr. om Marc Fischlin David Meyer Bogdan Warinschi Juan Garay Ashwin Nayak Stephanie Wehner Rosario Gennaro Gregory Neven Ke Yang TCC Steering Committee Mihir Bellare (Chair) UCSD, USA ? Ivan Damg? ard Arhus University, Denmark Oded Goldreich Weizmann Institute, Israel and Radcli?e Institute, USA Sha? Goldwasser MIT, USA and Weizmann Institute, Israel

This book constitutes the refereed proceedings of the 26th Annual International Conference on the Theory and Applications of Cryptographic Techniques, EUROCRYPT 2007, held in Barcelona, Spain in May 2007. The 33 revised full papers address all current foundational, theoretical and research aspects of cryptology, cryptography, and cryptanalysis as well as advanced applications.