The EUROCRYPT ’96 conference was sponsored by the International Asso- ation for Cryptologic Research (IACR)l, in cooperation with the University of Saragossa. It took place at the Palacio de Congresos in Saragossa, Spain, during May 12-16, 1996. This was the fifteenth annual EUROCRYPT conference (this name has been used since the third conference held in 1984), each of which has been held in a different city in Europe. For the second time, proceedings were available at the conference. JosC Pastor Franco, the General Chair, was resp- sible for local organization and registration. His contribution to the snccess of the conference is gratefully acknowledged. The Program Committee considered 126 submitted papers and selected 34 for presentation. Each paper was sent to all members of the Program Committee and was assigned to at least three of them for careful evaluation. There were also two invited talks. James L. Massey, this year’s IACR Distinguished Ltcturer, gave a lecture entitled “The difficulty with difficulty”. Massey is the third to receive this honor, the first two being Gustavus Simmons and Adi Shamir. Shafi Goldwasser gave an invited talk entitled “Multi party secure prools: past and present”. These proceedings contain revised versions of the 34 contributed talks. While the papers were carefully selected, they have not been refereed like submissions to a refereed journal. The authors bear full responsibility for the contents of their papers. Some authors may write final versions of their papers for publication in a refereed journal.