Network Working Group Y. Ni Internet-Draft C. P. Liu Intended status: Informational Q. Gao Expires: 24 April 2027 Huawei Z. Li Y. Xu CESI 21 October 2026 Security Requirements for AI Agents draft-ni-a2a-ai-agent-security-requirements-02 Abstract This document discusses security requirements for AI agents, covering different stages of security interactions. These include provisioning, registration, discovery, cross-domain interconnection, and access control. About This Document This note is to be removed before publishing as an RFC. The latest revision of this draft can be found at https://liuchunchi.github.io/draft-ni-a2a-ai-agent-security- requirements/draft-ni-a2a-ai-agent-security-requirements.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-ni-a2a-ai-agent-security- requirements/. Discussion of this document takes place on the WG Working Group mailing list (mailto:WG@example.com), which is archived at https://example.com/WG. Source for this draft and an issue tracker can be found at https://github.com/liuchunchi/draft-ni-a2a-ai-agent-security- requirements. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Ni, et al. Expires 24 April 2027 [Page 1] Internet-Draft Agent Security Requirements October 2026 Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 24 April 2027. Copyright Notice Copyright (c) 2026 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Architecture . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Provisioning, Registration, and Discovery . . . . . . . . . . 5 3.1. Identity Provisioning and Management . . . . . . . . . . 6 3.2. Secret Management . . . . . . . . . . . . . . . . . . . . 7 3.3. Agent Registration . . . . . . . . . . . . . . . . . . . 7 3.4. Agent Onboarding . . . . . . . . . . . . . . . . . . . . 8 3.5. Agent Discovery . . . . . . . . . . . . . . . . . . . . . 8 4. Cross-Domain Interconnection . . . . . . . . . . . . . . . . 9 4.1. Cross-Domain Identifier Interoperability . . . . . . . . 9 4.2. Secure Cross-Domain Transmission . . . . . . . . . . . . 9 4.3. Authenticating External Calls . . . . . . . . . . . . . . 9 4.4. IAM Integration . . . . . . . . . . . . . . . . . . . . . 10 5. Access Control . . . . . . . . . . . . . . . . . . . . . . . 10 5.1. Authorization Handling . . . . . . . . . . . . . . . . . 10 5.2. Authorization Models . . . . . . . . . . . . . . . . . . 10 5.3. Authorization Chaining Across Domains . . . . . . . . . . 11 5.4. Converting to Internal Workflow . . . . . . . . . . . . . 11 5.5. Interoperability for Heterogeneous Systems . . . . . . . 12 5.6. Zero Trust Analysis . . . . . . . . . . . . . . . . . . . 12 Ni, et al. Expires 24 April 2027 [Page 2] Internet-Draft Agent Security Requirements October 2026 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 7.1. Normative References . . . . . . . . . . . . . . . . . . 13 7.2. Informative References . . . . . . . . . . . . . . . . . 14 Revision History . . . . . . . . . . . . . . . . . . . . . . . . 14 Changes from -00 to -01 . . . . . . . . . . . . . . . . . . . . 15 Changes from -01 to -02 . . . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 1. Introduction With the widespread application of agentic AI technology across various business scenarios, its security issues have become increasingly prominent. This document aims to provide an architecture addressing security requirements across different stages of interactions in agentic AI use cases. These include provisioning, registration, discovery, cross-domain interconnection, and access control. This document establishes a starting point to guide discussions on agentic AI security design, development, and implementation. The target audience of this document is IETF security experts who wish to understand AI agents' behavioral patterns and evaluate whether the proposed security requirements are worthy of further security designs. 2. Architecture The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. Ni, et al. Expires 24 April 2027 [Page 3] Internet-Draft Agent Security Requirements October 2026 +----------------+ | Master Agent | +-^--------------+ +-+--------------+ | | Firewall | +-+--------------+ | -------------- (2) | Inter-domain-------------- | +------------------+---------------------------------+ | +-+--------------+ Intra-domain | | | | Firewall | | | +-+--------------+ | | +-v--------------+ | | +-------+ Master Agent | | | (3) | +----------------+ | | | (1) | | +----v-----+ +----------+ +----------+ | | | Agent +----> Agent +----> Agent | | | +----+-----+ +----------+ +----+-----+ | | | | | | +--v---------+ +---------v---+ | | | DB | | API | | | +------------+ +-------------+ | +----------------------------------------------------+ _Figure 1. Architecture of Agent Security Control and Management_ The architecture of agent security control and management is illustrated in Figure 1. There are three types of security interactions, in sequential order: 1. Provisioning, Registration, and Discovery: Creating agent identities, establishing initial trust, provisioning agent secrets and credentials, and onboarding agents to enable discovery. 2. Cross-Domain Interconnection: Enabling secure, authenticated communication between agents across different trust domains. 3. Access Control: The Master Agent validates both intra-domain and inter-domain access tokens, creates internal workflows, and manages different credentials for heterogeneous systems. Therefore, the architecture includes four components: Ni, et al. Expires 24 April 2027 [Page 4] Internet-Draft Agent Security Requirements October 2026 1. Firewall: A network security device designed to monitor, filter, and control incoming and outgoing network traffic based on predetermined security rules. 2. Master Agent: The central orchestrating entity that manages multi-agent operations, including cross-domain communication, workflow coordination, credential management, and security policy management. 3. Agents: Autonomous software entities deployed in various domains to perform specific tasks. 4. Heterogeneous Systems: API endpoints, microservices, tools, and databases. The above architecture is presented from the perspective of a service flow. From the identity management perspective, we recommend reusing existing IETF work such as WIMSE. The draft [I-D.ni-wimse-ai-agent-identity] discusses the applicability of WIMSE to agentic AI. 3. Provisioning, Registration, and Discovery Figure 2 shows the diagram of provisioning and registration, which includes Agent Credential Authority (ACA) and Agent Registry Service (ARS): 1. ACA (Agent Credential Authority): A trusted third party that issues and manages credentials for agents. Credential formats include, but are not limited to, X.509 certificates and identity tokens. 2. ARS (Agent Registry Service): A system responsible for agent identity registration and discovery. Ni, et al. Expires 24 April 2027 [Page 5] Internet-Draft Agent Security Requirements October 2026 +-------------------------------------------+ | | | +-----------------+ +------------------+ | | |Agent Credential | | Agent Registry | | | |Authority (ACA) | | Service (ARS) | | | +--------^--------+ +---------^--------+ | | | | | | ++---------------------++ | | || +----------+ || | | |+-----> Agent +----+| | | | +----------+ | | | | | | | | device/container | | | +-----------------------+ | | | +-------------------------------------------+ _Figure 2. Diagram for Provisioning and Registration_ 3.1. Identity Provisioning and Management Identity provisioning and management involve creating and assigning a verifiable digital identity to an agent. * Initial Trust Establishment: Initial trust can be established through one or more of the following trust anchors, including, but not limited to: a manufacturer-embedded immutable credential like an IDevID certificate; a hardware root of trust like a Trusted Platform Module (TPM) or Hardware Security Module (HSM); identity documents like an AWS Instance Identity Document or an Azure Managed Service Identity token. This step verifies the agent's execution environment (device, container, etc.) as trustworthy, allows the device or container to join the network, thereby enabling secure operations for all subsequent steps. * Credential Request: During a credential request, the agent must provide multiple proofs of its legitimacy, could include, for example, but not limited to: - Proof of Possession (PoP): A Certificate Signing Request (CSR) or other PoP forms signed with the agent's private key, demonstrating that the agent holds the private key corresponding to the requested identity. Ni, et al. Expires 24 April 2027 [Page 6] Internet-Draft Agent Security Requirements October 2026 - Remote Attestation Evidence or Result: A set of security- relevant claims about the Target Environment submitted to a RATS Verifier (which could be the ACA), providing information about operational status, health, configuration, or construction. - AI Bill of Materials (AIBOM): A comprehensive inventory that details the agent's supply chain, including models, datasets, configurations, dependencies, and related infrastructure. This prevents the use of vulnerable AI components. - Provider Endorsement: A digital signature or credential from the Agent Provider, ensuring the agent originated from a trusted source. - Identity Binding: A cryptographic binding to a specific human user or an organizational role to specify on whose behalf the agent operates and its authorized scope. * Credential Issuance: The ACA validates proofs and requests from the above two steps, if passed, it issues an agent-specific credential that may include its owner or requester identity, capabilities, locator, acceptable validation methods for the ARS. * Credential Lifecycle Management: The ACA not only issues credentials but also defines and enforces revocation policies. These policies are triggered by specific events, such as a detected security compromise, the agent's scheduled decommissioning, or key rotation. 3.2. Secret Management AI agents SHOULD NOT have direct access to secrets due to new threats like Prompt Injection. AI Agents SHOULD reuse secret management modules on the platform it operates on, for example, cloud secret managers or TEE/keystore/keychains on smart devices. Best practices like secret/credential generation, rotation and revocation apply. Agents SHOULD only obtain temporary access tokens or signed messages via a secure API or other kind of trusted intermediary. Guardrails also apply for general secret information exfiltration prevention. 3.3. Agent Registration After receiving a credential from the ACA, the agent then sends it to the ARS to authenticate itself and start the registration process. Ni, et al. Expires 24 April 2027 [Page 7] Internet-Draft Agent Security Requirements October 2026 * Authentication: The ARS must verify the legitimacy of the credential submitted by the agent. It must be signed or otherwise endorsed by the ACA. * Registration: The ARS then checks if the information signed by the ACA, such as the agent's capabilities, exactly matches the registration request sent by the agent. Upon successful validation, the ARS assigns the agent a unique identifier and establishes an agent record that links the identifier to its attributes. * Record Management: The ARS removes expired credentials and synchronizes with the ACA to ensure timely revocation of credentials, preventing the use of invalid or compromised credentials. 3.4. Agent Onboarding Agent onboarding differs between campus and cloud environments. On campus, agents use protocols like EAP-TLS for network access. In the cloud, the process involves injected sidecars, which register agents to the central service mesh registry automatically to enable communication and management. 3.5. Agent Discovery After agent onboarding, the discovery process enables entities (e.g., a human user, an agent, etc.) to find and connect with registered agents. * Authentication: The ARS must authenticate the entity initiating the discovery request. The requester is required to present a valid identity credential. * Capability Filtering and Matching: The ARS performs dynamic filtering based on the requester’s identity and query and returns only agent records relevant to the query, enforcing the principle of least privilege at the discovery layer. * Cross-Domain Agent Discovery: The ARS should support the discovery of trust bundles for verifying agent identities across administrative domains. [I-D.yao-dawn-agent-discovery-architect] proposes a DNS-like discovery architecture in which Agent Registries manage domain-level trust bundles, enabling agent identities registered in one administrative domain to be verified across domains. Ni, et al. Expires 24 April 2027 [Page 8] Internet-Draft Agent Security Requirements October 2026 4. Cross-Domain Interconnection 4.1. Cross-Domain Identifier Interoperability Different domains may use distinct identifier schemas. Possible methods include: * Pre-configured schema translation * Cross-domain identifier synchronization * A universal parsing framework or system 4.2. Secure Cross-Domain Transmission A mutual TLS (mTLS) connection is established between the external requesting agent and the master agent. The master agent terminates the mTLS connection and parses application-layer requests. In this case, the master agent functions as an OAuth resource server and manages internal task orchestration. 4.3. Authenticating External Calls The master agent then verifies the identity of the requesting agent, and whether or not it has permission to the requested service or agent. Different authentication methods might be possible: * API keys * Username-password * Pre-shared secrets * Assertions (for example, JWT Authorization Grants as discussed in [I-D.ietf-oauth-identity-chaining]) These methods may also be combined using AND/OR logic. During this process, the master agent might be able to identify the caller endpoint type: * Human user via browser or app * Human user via API * AI agents * Hardware or equipment via an IoT API Ni, et al. Expires 24 April 2027 [Page 9] Internet-Draft Agent Security Requirements October 2026 4.4. IAM Integration Since the agent may inherit its access rights from its owner or user, when authenticating requests, the validation might require integration of IAM systems for redirected verification. 5. Access Control 5.1. Authorization Handling The master agent acts as the OAuth 2.1 resource server and a Policy Enforcement Point (PEP). Its responsibilities are as follows: * Token Validation: The master agent must validate access tokens as described in OAuth 2.1 Section 5.2. If validation fails, it must respond according to OAuth 2.1 Section 5.3 error handling requirements. * Fine-Grained Policy Enforcement: The master agent serves as a PEP that queries a PDP (Policy Decision Point), such as Open Policy Agent (OPA), to evaluate the requester’s access request. The PDP functions by taking the master agent's query, pre-configured policies (supporting RBAC, ABAC, ReBAC models, etc.), and data as inputs to decide whether the requester is authorized for its intended action. The PDP then returns the final decision to the master agent for enforcement. 5.2. Authorization Models In enterprise environments, Role-based Access Control (RBAC) Attribute-based Access Control (ABAC) or Adaptive Access Control (AdBAC) are different access control models used in practice. Regarding access control models, there are 2 ways forward: * whatever the authorization model used in the enterprise itself applies to AI Agents. This leaves 2 cases possible: - The agent carries the identity and inherit access rights from its owner (a human or a department). Carrying such human identity will help security control points make decisions with sufficient context, and to the discretion of its internal security policy plus access control model. - The agent does not carry the identity from its owner. It carries independent security contexts rich enough for access control. * AI Agents require a new authorization model completely. Ni, et al. Expires 24 April 2027 [Page 10] Internet-Draft Agent Security Requirements October 2026 This section would require more discussion for best current practices. 5.3. Authorization Chaining Across Domains In an agentic AI use case, a request may traverse multiple master agents in multiple trust domains before completing. It is common that the requesting agent from domain A needs to access the master agent of domain B. During this process, the following information should be preserved: * Original requesting agent identity * Authorization context - Scope - Resource - Audience - Grant type - Assertion * Agent-to-Agent Context The Identity Chaining specification [I-D.ietf-oauth-identity-chaining] supports the propagation of identity and authorization information across domains. Building on this, the Cross-Domain Transaction Tokens draft [I-D.liu-oauth-cross-domain-txn-token] explores how workflow context can be securely transferred across domains to support the issuance of Transaction Tokens for downstream workflows. 5.4. Converting to Internal Workflow Complex tasks often require multi-agent collaboration. The master agent receives, parses, and extracts the original job request from the external requesting agent, then creates sequential workflows or parallel calls. This requires the master agent to have information about all callable internal API assets, agent capabilities, etc. * Batch Authorization Delegation: Parallel execution by multiple downstream agents may require different permissions for each subtask. The Batch Authorization Delegation draft [I-D.ni-oauth-batch-authorization-delegation] proposes requesting multiple fine-grained permissions in a single authorization Ni, et al. Expires 24 April 2027 [Page 11] Internet-Draft Agent Security Requirements October 2026 request, specifying the designated agent for each permission, and enabling each agent to obtain an appropriately scoped access token through token exchange. * Downscoping: If the master agent intends to use a workflow, it extracts the original caller's identity and authorization context, and initiates a new internal workflow. It should follow the principle of least privilege through Transaction Token downscoping, as specified in [I-D.ietf-oauth-transaction-tokens]. The access rights to each downstream workload decrease. * Agent-to-Agent Context: The agent-to-agent context and intent of the original requester must be preserved and propagated throughout the workflow to avoid authorization drift and context poisoning. 5.5. Interoperability for Heterogeneous Systems Within a domain, there might exist different types of heterogeneous systems or legacy systems that require different authentication methods. They could be API endpoints, microservices, tools or databases. The exact authentication methods are determined by the service itself, for example: * Identity tokens * API keys * Pre-shared secrets * Username-password * X.509 certificates As a result, the master agent also works as an intermediary credential manager that converts the formats, scopes, identity of the credential, bridging the gap between heterogeneous systems and platforms. Examples include: * Static secrets (API keys) to be exchanged to short-lived, on demand credentials (identity tokens) 5.6. Zero Trust Analysis The above information can be used as rich context that allows zero trust access control. There are three additional aspects that can be implemented to enhance the zero trust framework: Ni, et al. Expires 24 April 2027 [Page 12] Internet-Draft Agent Security Requirements October 2026 * Remote Attestation Results: For the PEP at the master agent or the internal resource server, Remote attestation results could also be part of the inputs, which could include the following information: - Roots of Trust (RoT) and trust anchors - Identifiers - Affiliations - Posture assessment results - Capabilities * Continuous Observability: The system should utilize OpenTelemetry (OTel) to track each call across agents, sending OTel’s telemetry, which records call frequency, error rates, and behavioral anomalies, etc. to the PDP for real-time assessment. * Microsegmentation: Based on the telemetry data, PDP can issue software-defined security policies to PEP at the perimeter of each segment to enforce microsegmentation, in order to prevent lateral movement of security risks. Possible granularity of microsegmentation includes: - per IP segment/subnet - per workload - per tags and attributes (of workload), etc. 6. IANA Considerations This document has no IANA actions. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . Ni, et al. Expires 24 April 2027 [Page 13] Internet-Draft Agent Security Requirements October 2026 7.2. Informative References [I-D.ietf-oauth-identity-chaining] Schwenkschuster, A., Kasselman, P., Burgin, K., Jenkins, M. J., Campbell, B., and A. Parecki, "OAuth Identity and Authorization Chaining Across Domains", Work in Progress, Internet-Draft, draft-ietf-oauth-identity-chaining-17, 19 July 2026, . [I-D.ietf-oauth-transaction-tokens] Tulshibagwale, A., Fletcher, G., and P. Kasselman, "Transaction Tokens", Work in Progress, Internet-Draft, draft-ietf-oauth-transaction-tokens-11, 30 July 2026, . [I-D.liu-oauth-cross-domain-txn-token] Liu, P. C. and N. Yuan, "Cross-domain Transaction Tokens", Work in Progress, Internet-Draft, draft-liu-oauth-cross- domain-txn-token-00, 3 July 2026, . [I-D.ni-oauth-batch-authorization-delegation] Yuan, N. and P. C. Liu, "Batch Authorization Delegation", Work in Progress, Internet-Draft, draft-ni-oauth-batch- authorization-delegation-00, 3 July 2026, . [I-D.ni-wimse-ai-agent-identity] Yuan, N., Liu, P. C., and M. Richardson, "WIMSE Applicability for AI Agents", Work in Progress, Internet- Draft, draft-ni-wimse-ai-agent-identity-03, 30 September 2026, . [I-D.yao-dawn-agent-discovery-architect] Yao, J., Liu, P. C., Geng, G., Chen, M., and H. Li, "DNS- like Agent Discovery Architecture", Work in Progress, Internet-Draft, draft-yao-dawn-agent-discovery-architect- 01, 17 September 2026, . Revision History Ni, et al. Expires 24 April 2027 [Page 14] Internet-Draft Agent Security Requirements October 2026 Changes from -00 to -01 * Expanded the security architecture to include agent discovery. * Added requirements for secret management and agent discovery. * Refined authorization models, cross-domain authorization, and internal workflow handling. * Expanded zero trust considerations, including microsegmentation. Changes from -01 to -02 * Add cross-domain agent discovery and trust bundle considerations. * Add cross-domain workflow context propagation. * Add batch authorization delegation for parallel multi-agent workflows. * Update references and fix editorial issues. Authors' Addresses Yuan Ni Huawei Email: niyuan1@huawei.com Chunchi Peter Liu Huawei Email: liuchunchi@huawei.com Qiangzhou Gao Huawei Email: gaoqiangzhou@huawei.com Zhenbin Li Email: robinli314@163.com Yuna Xu CESI Email: xuyuna@cesi.cn Ni, et al. Expires 24 April 2027 [Page 15]