]> Sandelman Software Works

mcr+ietf@sandelman.ca

Fraunhofer SIT

henk.birkholz@ietf.contact

Arm

yogesh.deshpande@arm.com

Linaro

thomas.fossati@linaro.org

Internet RATS Working Group Internet-Draft This document was attempting to clarifys and extends the meaning of Composite Attester from RFC9334. It has since been moved into the RATS wiki, and this I-D serves as a tombstone. A system of annotated diagram components is defined as a small language to explain the different ways that components can interact to form composites. These diagram components are then used to define a few popular classes of composites. About This Document Status information for this document may be found at . Discussion of this document takes place on the rats Working Group mailing list (), which is archived at . Subscribe at . Source for this draft and an issue tracker can be found at .

Introduction This document was attempting to clarify and extend the meaning of Composite Attester from . This work has been moved into the RATS wiki at: https://wiki.ietf.org/group/rats/atomic-composites

IANA Considerations There are none.

Acknowledgements Jun Zhang contributed the terms "Le Petit" and "Le Grand" to qualify Verifier, the original thought for Class 5 Composite Atteser and the description of the Nonce architecture.

Changelog

References Normative References RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. In network protocol exchanges, it is often useful for one end of a communication to know whether the other end is in an intended operating state. This document provides an architectural overview of the entities involved that make such tests possible through the process of generating, conveying, and evaluating evidentiary Claims. It provides a model that is neutral toward processor architectures, the content of Claims, and protocols. Fraunhofer SIT Independent Linaro University of Applied Sciences Bonn-Rhein-Sieg Google LLC The Conceptual Messages introduced by the RATS architecture (RFC 9334) are protocol-agnostic data units that are conveyed between RATS roles during remote attestation procedures. Conceptual Messages describe the meaning and function of such data units within RATS data flows without specifying a wire format, encoding, transport mechanism, or processing details. The initial set of Conceptual Messages is defined in Section 8 of RFC 9334 and includes Evidence, Attestation Results, Endorsements, Reference Values, and Appraisal Policies. This document introduces the Conceptual Message Wrapper (CMW) that provides a common structure to encapsulate these messages. It defines a dedicated CBOR tag, corresponding JSON Web Token (JWT) and CBOR Web Token (CWT) claims, and an X.509 extension. This allows CMWs to be used in CBOR-based protocols, web APIs using JWTs and CWTs, and PKIX artifacts like X.509 certificates. Additionally, the draft defines a media type and a CoAP content format to transport CMWs over protocols like HTTP, MIME, and CoAP. The goal is to improve the interoperability and flexibility of remote attestation protocols. Introducing a shared message format such as CMW enables consistent support for different attestation message types, evolving message serialization formats without breaking compatibility, and avoiding the need to redefine how messages are handled within each protocol. Informative References Trusted Computing Group Arm Limited Linaro Mediatek Inc The Arm Confidential Compute Architecture (CCA) is series of hardware and software innovations that enhance Arm’s support for Confidential Computing for large, compute-intensive workloads. Devices that implement CCA can produce attestation tokens as described in this memo, which are the basis for trustworthiness assessment of the Confidential Compute environment. This document specifies the CCA attestation token structure and semantics. The CCA attestation token is a profile of the Entity Attestation Token (EAT). This specification describes what claims are used in an attestation token generated by CCA compliant systems, how these claims get serialized to the wire, and how they are cryptographically protected. This informational document is published as an independent submission to improve interoperability with Arm's architecture. It is not a standard nor a product of the IETF.