This book constitutes the refereed proceedings of the 18th Annual International Cryptology Conference, CRYPTO'98, held in Santa Barbara, California, USA, in August 1998. The book presents 33 revised full papers selected from a total of 144 submissions received. Also included are two invited presentations. The papers are organized in topical sections on chosen ciphertext security, cryptanalysis of hash functions and block ciphers, distributed cryptography, zero knowledge, and implementation.