D’Agents: Security in a Multiple-Language, Mobile-Agent System
Reference: Robert S. Gray, David Kotz, George Cybenko, Daniela Rus (1998). Mobile Agents and Security (G. Vigna, ed.), Springer LNCS. Source file: gray-security-book.pdf. URL
Summary
This chapter describes the security architecture of D’Agents (formerly Agent Tcl), a mobile-agent system whose agents can be written in Tcl, Java, or Scheme. The authors frame mobile-agent security as four interrelated problems: protecting the host machine from malicious agents, protecting agents from each other, protecting an agent from a malicious machine, and limiting aggregate resource consumption across groups of machines.
For machine and inter-agent protection, D’Agents relies on PGP-based cryptographic authentication of owners, identity-based resource managers that enforce access-control policies, and secure execution environments (Safe Tcl, Java security managers, Scheme 48 modules) separated cleanly from policy. For group-of-machine protection they plan an electronic-cash market approach; for agent-from-host attacks they survey partial techniques (detection via audit trails, encrypted computation, trusted reference machines) since full prevention requires hardware support they do not assume.
Key Ideas
- Four interrelated mobile-agent security problems.
- Separation of enforcement mechanism from policy.
- Multi-language support with a uniform C/C++ server library.
- Cryptographic authentication + per-identity resource managers.
- Open problem: protecting agents from malicious hosts without trusted hardware.
Connections
Conceptual Contribution
- Claim: Mobile-agent security comprises four distinct but interrelated problems (protecting machine, protecting other agents, protecting agent from host, protecting group of machines); solving them requires layered mechanisms that cleanly separate enforcement from policy and span multiple execution languages.
- Mechanism: Architectural description of D’Agents’ four-level stack (transport, server, interpreter, agents); PGP-based owner authentication; language-specific enforcement modules (Safe Tcl, Java security manager, Scheme 48) routed through a language-independent resource manager; planned e-cash market approach for aggregate-resource protection; survey of partial techniques (audit trails, encrypted computation) for the agent-from-host problem.
- Concepts introduced/used: Mobile Agent, Four Security Problems, Mechanism vs Policy, Safe Tcl, Resource Manager Agent, PGP Authentication, Audit Trail, Encrypted Computation
- Stance: engineering / survey
- Relates to: Extends the earlier Agent Tcl Flexible Secure Mobile Agents with a mature security story; shares threat concerns with AI Agents Under Threat and Distributed Security; policy/mechanism separation echoes the sandboxing principles of Extensible Distributed Coordination and Agents Secure Interaction in Data Driven Languages.
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