This book constitutes the refereed proceedings of the International Exhibition and Congress on Network Security, CQRE'99, held in Düsseldorf, Germany, in November/December 1999. The 15 revised full papers presented together with two invited papers and five workshop papers were carefully reviewed and selected from 46 submissions. The papers are organized in sections on risk management, security design, electronic payment, smartcards, applications, PKI experiences, mobile security, cryptography, network security, key recovery, intrusion detection, interoperability, and biometrics.