This volume contains the proceedings of the Eurocrypt '89 conference, a workshop on theory and applications of cryptographic techniques. The International Association for Cryptologic Research (IACR) organizes two conferences each year, one in Europe and one in the United States. Eurocrypt '89 was the seventh European conference. The volume includes revised versions of nearly all the contributions presented at the conference, including shortened versions of the talks given at the special rump session for recent results. Recent outbreaks of viruses, worms and computer fraud together with progress in telecommunications, computer networks and automated banking have considerably increased the interest in data security techniques, where cryptography is generaly considered to be the most important tool. In this area of data security, where high stakes are at risk, up-to-date information is crucial. This book is organized into sections on public-key cryptosystems, theory, zero-knowledge protocols, applications, signature and untraceability, cryptanalysis, sharing and authentication schemes, sequences, algorithms, old problems, and impromptu talks.