Hiding role assignment in mission‐critical collaborative systems

SUMMARY In a mission critical collaboration system, a group of roles are assigned to computer nodes connected by a communication network. Role assignment is mission-critical information and needs to be protected. In this paper, we develop methods to effectively and efficiently protect the information of role assignment from traffic analysis, a passive attack. To measure the system security, we introduce a metric of detection probability, defined as the probability that a role assignment can be discovered. A heuristic greedy algorithm is given to minimize the resource consumption while guaranteeing a low detection-probability level. Our performance evaluation shows that the algorithm proposed in this paper performs well in terms of execution time and resource usage compared to an exhaustive search algorithm. We also propose to use additional means (e.g. additional nodes) to further increase the security level of a system at the cost of a mild resource consumption increase. Copyright  2002 John Wiley & Sons, Ltd.