Trusted AI Agent Transactions, Part 2: PingFederate Token Exchange

In the second part of the article on Trusted AI Agent Transactions, the focus is on PingFederate's role as a Transaction Token Service (TTS). A TTS uses the RFC 8693 token exchange protocol to generate a Txn-Token. PingFederate assumes this role in the Tokenetes architecture.

The agent sends two tokens: its subject_token (the user's access token) and actor_token (the agent workload's JWT-SVID). Neither token can replace the other. The TTS profile relies on authenticated TTS clients, but it also includes explicit actor evidence to bind a logical AI agent to its runtime workload.

The subject token is the user's OAuth access token, while the actor token is a JWT-SVID issued by SPIRE. The agent submits both tokens to PingFederate in a form-encoded RFC 8693 request, using TLS over a protected request body. PingFederate validates the subject token using its subject token processor and the JWT-SVID signature, issuer, audience, time, key ID, and algorithm using its SPIRE processor.

After validating both tokens independently, PingFederate issues a short-lived, signed JWT conforming to the Transaction Tokens profile. This Txn-Token includes immutable transaction context such as the target, tool, logical AgentID, and workload details. Unlike OAuth tokens, the Txn-Token is not sent in the OAuth Authorization header between internal workloads.