Computer Security ESORICS 98 : 5th European Symposium on Research in Computer Security Louvain la Neuve Belgium September 16 18 1998 Proceedings This book constitutes the refereed proceedings of the 5th European Symposium on Research in Computer Security ESORICS 98 held in Louvain la Neuve Belgium in September 1998.The 24 revised full papers presented were carefully reviewed and selected from a total of 57 submissions. The papers provide current results from research and development in design and specification of security policies access control modelling and protocol analysis mobile systems and anonymity Java and mobile code watermarking intrusion detection and prevention and specific threads