The papers in this volume were presented at the CRYPTO '88 conference on theory and applications of cryptography, held in Santa Barbara, California, August 21-25, 1988. The papers were chosen for their perceived originality and often represent preliminary reports on continuing research. The main sections deal with the following topics: Zero-Knowledge, Number Theory, Pseudorandomness, Signatures, Complexity, Protocols, Security, Cryptoanalysis. As such, they will give the committed reader a unique insight into the very latest developments in the field.