draft-ietf-rats-reference-interaction-models-02.txt		draft-ietf-rats-reference-interaction-models-03.txt
	RATS Working Group H. Birkholz		RATS Working Group H. Birkholz
	Internet-Draft M. Eckel		Internet-Draft M. Eckel
	Intended status: Informational Fraunhofer SIT		Intended status: Informational Fraunhofer SIT
	Expires: 28 October 2021 W. Pan		Expires: 14 January 2022 W. Pan
	Huawei Technologies		Huawei Technologies
	E. Voit		E. Voit
	Cisco		Cisco
	26 April 2021		13 July 2021
	Reference Interaction Models for Remote Attestation Procedures		Reference Interaction Models for Remote Attestation Procedures
	draft-ietf-rats-reference-interaction-models-02		draft-ietf-rats-reference-interaction-models-03
	Abstract		Abstract
	This document describes interaction models for remote attestation		This document describes interaction models for remote attestation
	procedures (RATS). Three conveying mechanisms -- Challenge/Response,		procedures (RATS). Three conveying mechanisms -- Challenge/Response,
	Uni-Directional, and Streaming Remote Attestation -- are illustrated		Uni-Directional, and Streaming Remote Attestation -- are illustrated
	and defined. Analogously, a general overview about the information		and defined. Analogously, a general overview about the information
	elements typically used by corresponding conveyance protocols are		elements typically used by corresponding conveyance protocols are
	highlighted.		highlighted.
	skipping to change at page 1, line 39 ¶		skipping to change at page 1, line 39 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on 28 October 2021.		This Internet-Draft will expire on 14 January 2022.
	Copyright Notice		Copyright Notice
	Copyright (c) 2021 IETF Trust and the persons identified as the		Copyright (c) 2021 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents (https://trustee.ietf.org/		Provisions Relating to IETF Documents (https://trustee.ietf.org/
	license-info) in effect on the date of publication of this document.		license-info) in effect on the date of publication of this document.
	Please review these documents carefully, as they describe your rights		Please review these documents carefully, as they describe your rights
	skipping to change at page 6, line 11 ¶		skipping to change at page 6, line 11 ¶
	Attester itself. The corresponding trustable statements are called		Attester itself. The corresponding trustable statements are called
	Endorsements and originate from external, trustable entities that		Endorsements and originate from external, trustable entities that
	take on the role of an Endorser (e.g., supply chain entities).		take on the role of an Endorser (e.g., supply chain entities).
	5. Normative Prerequisites		5. Normative Prerequisites
	In order to ensure an appropriate conveyance of Evidence via		In order to ensure an appropriate conveyance of Evidence via
	interaction models in general, the following set of prerequisites		interaction models in general, the following set of prerequisites
	MUST be in place to support the implementation of interaction models:		MUST be in place to support the implementation of interaction models:
			Authentication Secret: An Authentication Secret MUST be available
			exclusively to an Attesting Environment of an Attester.
			The Attester MUST protect Claims with that Authentication Secret,
			thereby proving the authenticity of the Claims included in
			Evidence. The Authentication Secret MUST be established before
			RATS can take place.
	Attester Identity: A statement about a distinguishable Attester made		Attester Identity: A statement about a distinguishable Attester made
	by an Endorser without accompanying evidence about its validity,		by an Endorser.
	used as proof of identity.
	The provenance of Evidence with respect to a distinguishable		The provenance of Evidence with respect to a distinguishable
	Attesting Environment MUST be correct and unambiguous.		Attesting Environment MUST be correct and unambiguous.
	An Attester Identity MAY be a unique identity, MAY be included in		An Attester Identity MAY be an Authentication Secret which is
	a zero-knowledge proof (ZKP), MAY be part of a group signature, or		available exclusively to one of the Attesting Environments of an
	it MAY be a randomized DAA credential [DAA].		Attester. It MAY be a unique identity, MAY be included in a zero-
			knowledge proof (ZKP), MAY be part of a group signature, or it MAY
			be a randomized DAA credential [DAA].
	Attestation Evidence Authenticity: Attestation Evidence MUST be		Attestation Evidence Authenticity: Attestation Evidence MUST be
	authentic.		authentic.
	In order to provide proofs of authenticity, Attestation Evidence		In order to provide proofs of authenticity, Attestation Evidence
	SHOULD be cryptographically associated with an identity document		SHOULD be cryptographically associated with an identity document
	(e.g. an PKIX certificate or trusted key material, or a randomized		(e.g., a PKIX certificate or trusted key material, or a randomized
	DAA credential [DAA]), or SHOULD include a correct and unambiguous		DAA credential [DAA]), or SHOULD include a correct, unambiguous
	and stable reference to an accessible identity document.		and stable reference to an accessible identity document.
	Authentication Secret: An Authentication Secret MUST be available
	exclusively to an Attester's Attesting Environment.
	The Attester MUST protect Claims with that Authentication Secret,
	thereby proving the authenticity of the Claims included in
	Evidence. The Authentication Secret MUST be established before
	RATS can take place.
	Evidence Freshness: Evidence MUST include an indicator about its		Evidence Freshness: Evidence MUST include an indicator about its
	freshness that can be understood by a Verifier. Analogously,		freshness that can be understood by a Verifier. Analogously,
	interaction models MUST support the conveyance of proofs of		interaction models MUST support the conveyance of proofs of
	freshness in a way that is useful to Verifiers and their appraisal		freshness in a way that is useful to Verifiers and their appraisal
	procedures.		procedures.
	Evidence Protection: Evidence MUST be a set of well-formatted and		Evidence Protection: Evidence MUST be a set of well-formatted and
	well-protected Claims that an Attester can create and convey to a		well-protected Claims that an Attester can create and convey to a
	Verifier in a tamper-evident manner.		Verifier in a tamper-evident manner.
	skipping to change at page 7, line 16 ¶		skipping to change at page 7, line 16 ¶
	This section defines the information elements that are vital to all		This section defines the information elements that are vital to all
	kinds interaction models. Varying from solution to solution, generic		kinds interaction models. Varying from solution to solution, generic
	information elements can be either included in the scope of protocol		information elements can be either included in the scope of protocol
	messages (instantiating Conceptual Messages) or can be included in		messages (instantiating Conceptual Messages) or can be included in
	additional protocol parameters or payload. Ultimately, the following		additional protocol parameters or payload. Ultimately, the following
	information elements are required by any kind of scalable remote		information elements are required by any kind of scalable remote
	attestation procedure using one or more of the interaction models		attestation procedure using one or more of the interaction models
	provided.		provided.
	Attester Identity ('attesterIdentity'): _mandatory_
	A statement about a distinguishable Attester made by an Endorser
	without accompanying evidence about its validity - used as proof
	of identity.
	Authentication Secret IDs ('authSecIDs'): _mandatory_		Authentication Secret IDs ('authSecIDs'): _mandatory_
	A statement representing an identifier list that MUST be		A statement representing an identifier list that MUST be
	associated with corresponding Authentication Secrets used to		associated with corresponding Authentication Secrets used to
	protect Claims included in Evidence.		protect Claims included in Evidence.
	Each Authentication Secret is uniquely associated with a		Each Authentication Secret is uniquely associated with a
	distinguishable Attesting Environment. Consequently, an		distinguishable Attesting Environment. Consequently, an
	Authentication Secret ID also identifies an Attesting Environment.		Authentication Secret ID also identifies an Attesting Environment.
	skipping to change at page 11, line 26 ¶		skipping to change at page 11, line 6 ¶
	With the Handle, the Authentication Secret IDs, and the collected		With the Handle, the Authentication Secret IDs, and the collected
	Claims, the Attester produces signed Evidence. That is, it digitally		Claims, the Attester produces signed Evidence. That is, it digitally
	signs the Handle and the collected Claims with a cryptographic secret		signs the Handle and the collected Claims with a cryptographic secret
	identified by the Authentication Secret ID. This is done once per		identified by the Authentication Secret ID. This is done once per
	Attesting Environment which is identified by the particular		Attesting Environment which is identified by the particular
	Authentication Secret ID. The Attester communicates the signed		Authentication Secret ID. The Attester communicates the signed
	Evidence as well as all accompanying Event Logs back to the Verifier.		Evidence as well as all accompanying Event Logs back to the Verifier.
	While it is crucial that Claims, the Handle, and the Attester		While it is crucial that Claims, the Handle, and the Attester
	Identity information MUST be cryptographically bound to the signature		Identity information (i.e., the Authentication Secret) MUST be
	of Evidence, they MAY be presented obfuscated, encrypted, or		cryptographically bound to the signature of Evidence, they MAY be
	cryptographically blinded. For further reference see section		presented obfuscated, encrypted, or cryptographically blinded. For
	Section 10.		further reference see section Section 10.
	As soon as the Verifier receives the signed Evidence and Event Logs,		As soon as the Verifier receives the Evidence and the Event Logs, it
	it appraises the Evidence. For this purpose, it validates the		appraises the Evidence. For this purpose, it validates the
	signature, the Attester Identity, and the Handle, and then appraises		signature, the Attester Identity, and the Handle, and then appraises
	the Claims. Appraisal procedures are application-specific and can be		the Claims. Appraisal procedures are application-specific and can be
	conducted via comparison of the Claims with corresponding Reference		conducted via comparison of the Claims with corresponding Reference
	Values, such as Reference Integrity Measurements. The final output		Values, such as Reference Integrity Measurements. The final output
	of the Verifier are Attestation Results. Attestation Results		of the Verifier are Attestation Results. Attestation Results
	constitute new Claim Sets about the properties and characteristics of		constitute new Claim Sets about the properties and characteristics of
	an Attester, which enables Relying Parties, for example, to assess an		an Attester, which enables Relying Parties, for example, to assess an
	Attester's trustworthiness.		Attester's trustworthiness.
	7.2. Uni-Directional Remote Attestation		7.2. Uni-Directional Remote Attestation
	skipping to change at page 18, line 50 ¶		skipping to change at page 18, line 50 ¶
	12.2. Informative References		12.2. Informative References
	[DAA] Brickell, E., Camenisch, J., and L. Chen, "Direct		[DAA] Brickell, E., Camenisch, J., and L. Chen, "Direct
	Anonymous Attestation", page 132-145, ACM Proceedings of		Anonymous Attestation", page 132-145, ACM Proceedings of
	the 11rd ACM conference on Computer and Communications		the 11rd ACM conference on Computer and Communications
	Security, 2004.		Security, 2004.
	[I-D.birkholz-rats-tuda]		[I-D.birkholz-rats-tuda]
	Fuchs, A., Birkholz, H., McDonald, I. E., and C. Bormann,		Fuchs, A., Birkholz, H., McDonald, I. E., and C. Bormann,
	"Time-Based Uni-Directional Attestation", Work in		"Time-Based Uni-Directional Attestation", Work in
	Progress, Internet-Draft, draft-birkholz-rats-tuda-04, 13		Progress, Internet-Draft, draft-birkholz-rats-tuda-05, 12
	January 2021, <https://www.ietf.org/archive/id/draft-		July 2021, <https://www.ietf.org/archive/id/draft-
	birkholz-rats-tuda-04.txt>.		birkholz-rats-tuda-05.txt>.
	[I-D.ietf-rats-architecture]		[I-D.ietf-rats-architecture]
	Birkholz, H., Thaler, D., Richardson, M., Smith, N., and		Birkholz, H., Thaler, D., Richardson, M., Smith, N., and
	W. Pan, "Remote Attestation Procedures Architecture", Work		W. Pan, "Remote Attestation Procedures Architecture", Work
	in Progress, Internet-Draft, draft-ietf-rats-architecture-		in Progress, Internet-Draft, draft-ietf-rats-architecture-
	12, 23 April 2021, <https://www.ietf.org/archive/id/draft-		12, 23 April 2021, <https://www.ietf.org/archive/id/draft-
	ietf-rats-architecture-12.txt>.		ietf-rats-architecture-12.txt>.
	[I-D.ietf-rats-tpm-based-network-device-attest]		[I-D.ietf-rats-tpm-based-network-device-attest]
	Fedorkow, G., Voit, E., and J. Fitzgerald-McKay, "TPM-		Fedorkow, G., Voit, E., and J. Fitzgerald-McKay, "TPM-
	based Network Device Remote Integrity Verification", Work		based Network Device Remote Integrity Verification", Work
	in Progress, Internet-Draft, draft-ietf-rats-tpm-based-		in Progress, Internet-Draft, draft-ietf-rats-tpm-based-
	network-device-attest-06, 7 December 2020,		network-device-attest-07, 10 June 2021,
	<https://www.ietf.org/archive/id/draft-ietf-rats-tpm-		<https://www.ietf.org/archive/id/draft-ietf-rats-tpm-
	based-network-device-attest-06.txt>.		based-network-device-attest-07.txt>.
	[turtles] Rudnicki, R., "Turtles All the Way Down: Foundation,		[turtles] Rudnicki, R., "Turtles All the Way Down: Foundation,
	Edifice, and Ruin in Faulkner and McCarthy",		Edifice, and Ruin in Faulkner and McCarthy",
	DOI 10.1353/fau.2010.0002, The Faulkner Journal 25.2,		DOI 10.1353/fau.2010.0002, The Faulkner Journal 25.2,
	2010, <https://doi.org/10.1353/fau.2010.0002>.		2010, <https://doi.org/10.1353/fau.2010.0002>.
	Appendix A. CDDL Specification for a simple CoAP Challenge/Response		Appendix A. CDDL Specification for a simple CoAP Challenge/Response
	Interaction		Interaction
	The following CDDL specification is an exemplary proof-of-concept to		The following CDDL specification is an exemplary proof-of-concept to
End of changes. 15 change blocks.
	36 lines changed or deleted		31 lines changed or added
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