Agent Registry and Discovery Security

An agent registry is a service that tracks which agents exist, what capabilities they have, and how to reach them. Discovery is the process by which agents find each other through the registry. Compromising the registry gives an attacker control over the topology of the entire multi-agent system.

Registry as a Critical Service

The registry is the phone book of the agent system. If an attacker can modify registry entries, they can redirect traffic from a legitimate agent to a malicious one. If they can add entries, they can introduce rogue agents. If they can delete entries, they can cause denial of service by making agents unreachable.

Authentication and Authorization

Every registry operation should require authentication. Use separate permissions for read, write, and delete operations. Most agents only need read access to discover other agents. Only administrative principals should have write or delete access.

registry_policy:
  - principal_role: "agent"
    operations: ["read"]
    effect: "allow"
  - principal_role: "admin"
    operations: ["read", "write", "delete"]
    effect: "allow"

Integrity Verification

Sign registry entries with the registering authority's key. When an agent discovers another agent through the registry, it verifies the entry's signature before trusting the endpoint or public key listed in the entry. Unsigned or invalidly signed entries are rejected.

Change Auditing

Log every registry modification with timestamp, principal, and previous value. This audit log enables detection of unauthorized changes and supports incident investigation. Authensor's receipt chain can capture registry events alongside action events for unified auditing.

Stale Entry Detection

Implement heartbeat or health check mechanisms. Agents that stop responding should be automatically flagged in the registry. Stale entries that point to terminated agents can be exploited if the terminated agent's endpoint is later occupied by an attacker.

The registry is infrastructure. Treat its security with the same rigor you would apply to a certificate authority or DNS server.