This volume gives the proceedings of Crypto '90, held at the University of California at Santa Barbara, August 11-15, 1990. The conference attracted 227 participants from twenty countries, with attendees from academia, industry, and government. The program provided a balance between the theoretical and the practical aspects of cryptography to meet the needs and diversified interests of the various groups. The selected papers are organized into sections on cryptanalysis, protocols, algebra and number theory, signatures and authentication, secret sharing, key distribution,hash functions, zero-knowledge, randomness, applications, design and analysis, and impromptu talks.