A DISTRIBUTED SERVICE REGISTRY FOR RESOURCE SHARING AMONG AD-HOC DYNAMIC COALITIONS Ravi Mukkamala,^ Vijayalakshmi Atluri*,^ and Janice Warner^ Department of Computer Science Old Dominion University Norfolk, VA 23529 mukka@cs.odu.edu '^MSIS Department and CIMIC Rutgers University Newark, NJ 07012 {janice.atluri} @clmic.rutgers.edu Abstract In a dynamic coalition environment, it is essential to allow automatic sharing of resources among coalition members. The challenge is to facilitate such sharing while adhering to the security policies of each coalition. To accomplish this, a dynamic coalition-based access control (DCBAC) has been proposed earlier, where security policies enforced by each coalition member are published in a centralized coalition service registry (GSR). In this paper, we propose a dis- tributed coalition service registry (DCSR) system. In the DCSR system, several service registry agents cooperate to provide controlled access to resources. Dis- tribution of the registries results in improved availability, higher concurrency, better response times to user queries, and enhanced flexibility. We employ se- cure group multicasting to communicate among the DCSR agents. The paper outlines the DCSR system, the supported functionalities and its underlying in- frastructure. 1. Introduction It is often necessary for organizations to come together to share resources without prior planning to accomphsh a certain task at hand. This is driven by a number of applications including emergency and disaster management, peace keeping, humanitarian operations, or simply virtual enterprises. As an *The work of Atluri and Warner is supported in part by the National Science Foundation under grant IIS- 0306838.