Hamilton E. Link

Agent-Based Control of Distributed Infrastructure Resources

Managing distributed infrastructure resources is usually accomplished by telephone calls among the managers and operators. This works reasonably well under ordinary circumstances but breaks down—often catastrophically—under stress. Individual motivation, long response times, and poor situation awareness interfere with operation and can even cause breakdowns. Broadly distributed operations would more robust and fail more gracefully than centralized systems, but remain unlikely given the difficulty in operating large infrastructures even with modern Supervisory Control And Data Acquisition (SCADA) systems. The solution is management by distributed software that maintains normal operation, enforces operational and security policy, deals with contingencies, and protects against malicious indsiders, errors, and outright attacks. We specify a distributed agent coalition able to accomplish this for distributed electric power and describe a prototype implementation based on Sandia-developed technology.

Clarifying obfuscation: improving the security of white-box DES

To ensure the security of software executing on malicious hosts, as in digital rights management (DRM) applications, it is desirable to encrypt or decrypt content using white-box-encoded cryptographic algorithms in the manner of Chow et al. (2002). Such encoded algorithms must run on an adversarys machine without revealing the private key information used, despite the adversarys ability to observe and manipulate the running algorithm. We have implemented obfuscated (white-box) DES and triple-DES algorithms along the lines of Chow et al., with alterations that improve the security of the key. Our system is secure against two previously published attacks on Chow et al.s system, and our own adaptation of a statistical bucketing attack on their system.

The Role of Conversation Policy in Carrying Out Agent Conversations

Structured conversation diagrams, or conversation specifications, allow agents to have predictable interactions and achieve predefined information-based goals, but they lack the flexibility needed to function robustly in an unpredictable environment. We propose a mechanism that dynamically combines conversation structures with separately established policies to generate conversations. Policies establish limitations, constraints, and requirements external to specific planned interaction and can be applied to broad sets of activity. Combining a separate policy with a conversation specification simplifies the specification of conversations and allows contextual issues to be dealt with more straightforwardly during agent communication. By following the conversation specification when possible and deferring to the policy in exceptional circumstances, an agent can function predictably under normal situations and still act rationally in abnormal situations. Different conversation policies applied to a given conversation specification can change the nature of the interaction without changing the specification.

Agent-Based Mediation and Cooperative Information Systems

This report describes the results of research and development in the area of communication among disparate species of software agents. The two primary elements of the work are the formation of ontologies for use by software agents and the means by which software agents are instructed to carry out complex tasks that require interaction with other agents. This work was grounded in the areas of commercial transport and cybersecurity.