Grant: Discovery Grants Program - Individual

The wide acceptance of Internet-based technologies, the pervasiveness of transaction-based techniques in a multitude of systems (such as telecommunication ones), as well as the emergence of Grid systems, all strongly emphasize the paramount importance of distributed algorithms in today's computing world. Also, the use of mobile agents is becoming increasingly popular when computing in networked environments. But the presence of security threats greatly complicates solutions for all but non-trivial tasks. That is, in systems supporting mobile agents, security is the most pressing concern, and possibly the most difficult to address. The overall objective of this research consists in developing efficient and testable distributed algorithms that use mobile agents to solve non-trivial tasks in unsafe networks, that is, in the presence of security threats. The proposed research is organized into three broad goals: Goal 1: Investigate distributed algorithms in the presence of harmful hosts;Goal 2: Investigate distributed algorithms in an unsafe network using the mobile faults model.;Goal 3: Develop a testable model for the validation of distributed algorithms in an unsafe network. Goal 1 specifically focuses on networks with harmful hosts. We are particularly interested in solutions that constrain as much as possible the requirements imposed on agents and network (in order to maximize the feasibility of the realization of such solutions on actual networks supporting agents). More specifically, we aim for algorithms that are as efficient as possible while not requiring loosely constrained (possibly unrealistic) mechanisms. All work pertaining to Goal 1 is rooted in the use of the processor failure model, that is, a model in which faults are localized in nodes of the network. In contrast, Goal 2 adopts the more general mobile faults model. Goal 2 is two-fold: a) investigate how to adapt distributed algorithms that use the processor failure model in an unsafe network to instead use the mobile faults model and b) develop new efficient distributed algorithms in unsafe networks that adopt the mobile faults model. Finally, Goal 3 addresses the testing of distributed algorithms in unsafe networks.