this book constitutes the refereed proceedings of the 20th annual international cryptology conference, crypto 2000, held in santa barbara, ca, usa in august 2000. the 32 revised full papers presented together with one invited contribution were carefully reviewed and selected from 120 submissions. the papers are organized in topical sections on xtr and ntru, privacy for databases, secure distributed computation, algebraic cryptosystems, message authentication, digital signatures, cryptanalysis, traitor tracing and broadcast encryption, symmetric encryption, to commit or not to commit, protocols, and stream ciphers and boolean functions.