@techreport{hartman-credential-broker-4-agents-00, number = {draft-hartman-credential-broker-4-agents-00}, type = {Internet-Draft}, institution = {Internet Engineering Task Force}, publisher = {Internet Engineering Task Force}, note = {Work in Progress}, url = {https://datatracker.ietf.org/doc/draft-hartman-credential-broker-4-agents/00/}, author = {Kenneth G. Hartman}, title = {{Credential Broker for Agents (CB4A)}}, pagetotal = 30, year = 2026, month = mar, day = 29, abstract = {This document specifies a Credential Broker for Agents (CB4A). a credential vaulting and brokering architecture that mediates AI agent access to API credentials. Agents never hold real long-lived credentials. Instead, they receive short-lived, narrowly scoped, auditable proxy credentials issued by a broker that separates policy decisions from credential delivery. The architecture addresses the "credential sprawl" risk inherent in agentic AI, where agents aggregating access across many services become high-value compromise targets. CB4A builds on SPIFFE/SPIRE for workload identity, uses a Policy Decision Point / Credential Delivery Point separation inspired by NIST SP 800-207, and employs DPoP (RFC 9449) for sender-constrained token binding. The specification defines three credential proxy models, a tiered approval framework, and a comprehensive threat model with ten identified threats and their mitigations.}, }