PDCS 2004 International Workshop on Security in Parallel and Distributed Systems (in conjunction with the 17th International Conference on Parallel and Distributed Computing Systems), San Francisco, CA, USA, September 15-17, 2004. (submissions due May 31, 2004) In recent years, interest has increased in the field of security of parallel and distributed systems, which include the control mechanisms, mobile code security, denial-of-service attacks, trust management, modeling of information flow and its application to confidentiality policies, system composition, and covert channel analysis. We will focus our program on issues related to important properties of system security, such as measurability, sustainability, affordability, and usability in parallel and distributed systems. Topics of interest include: . Distributed Access Control and Trust Management . Key Management and Authentication . Privacy and Anonymity . Benchmark and Security Analysis . Security for Peer to Peer systems and Grid Computing Systems . Secure Multicast and Broadcast . Secure multiparty and two-party computations . Computer and Network Forensics . Denial-of-service Attacks and Countermeasures . Secure E-Commerce/E-Business . Security Verification . Distributed Database Security . Digital Rights Management . Secure Mobile Agents and Mobile Code . Intrusion detection . Security in ad-hoc and sensor networks . World Wide Web Security More information can be found at the conference web site at http://securityworkshop.ece.iastate.edu