< draft-ietf-cose-countersign-00.txt		draft-ietf-cose-countersign-01.txt >
	COSE Working Group J. Schaad		COSE Working Group J. Schaad
	Internet-Draft August Cellars		Internet-Draft August Cellars
	Intended status: Standards Track September 4, 2020		Intended status: Standards Track R. Housley, Ed.
	Expires: March 8, 2021		Expires: 10 April 2021 Vigil Security
			7 October 2020
	CBOR Object Signing and Encryption (COSE): Countersignatures		CBOR Object Signing and Encryption (COSE): Countersignatures
	draft-ietf-cose-countersign-00		draft-ietf-cose-countersign-01
	Abstract		Abstract
	Concise Binary Object Representation (CBOR) is a data format designed		Concise Binary Object Representation (CBOR) is a data format designed
	for small code size and small message size. CBOR Object Signing and		for small code size and small message size. CBOR Object Signing and
	Encryption (COSE) defines a set of security services for CBOR. This		Encryption (COSE) defines a set of security services for CBOR. This
	document defines a countersignature algorithm along with the needed		document defines a countersignature algorithm along with the needed
	header parameters and CBOR tags for COSE.		header parameters and CBOR tags for COSE.
	Contributing to this document		Contributing to this document
	This note is to be removed before publishing as an RFC.		This note is to be removed before publishing as an RFC.
	The source for this draft is being maintained in GitHub. Suggested		The source for this draft is being maintained in GitHub. Suggested
	changes should be submitted as pull requests at https://github.com/		changes should be submitted as pull requests at https://github.com/
	cose-wg/cose-rfc8152bis. Instructions are on that page as well.		cose-wg/countersign. Instructions are on that page as well.
	Editorial changes can be managed in GitHub, but any substantial		Editorial changes can be managed in GitHub, but any substantial
	issues need to be discussed on the COSE mailing list.		issues need to be discussed on the COSE mailing list.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	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 March 8, 2021.		This Internet-Draft will expire on 10 April 2021.
	Copyright Notice		Copyright Notice
	Copyright (c) 2020 IETF Trust and the persons identified as the		Copyright (c) 2020 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
	and restrictions with respect to this document. Code Components		and restrictions with respect to this document. Code Components
	extracted from this document must include Simplified BSD License text		extracted from this document must include Simplified BSD License text
	as described in Section 4.e of the Trust Legal Provisions and are		as described in Section 4.e of the Trust Legal Provisions and are
	provided without warranty as described in the Simplified BSD License.		provided without warranty as described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1. Requirements Terminology . . . . . . . . . . . . . . . . 4		1.1. Requirements Terminology . . . . . . . . . . . . . . . . 3
	1.2. CBOR Grammar . . . . . . . . . . . . . . . . . . . . . . 4		1.2. CBOR Grammar . . . . . . . . . . . . . . . . . . . . . . 4
	1.3. Document Terminology . . . . . . . . . . . . . . . . . . 4		1.3. Document Terminology . . . . . . . . . . . . . . . . . . 4
	2. Countersignature Header Parameters . . . . . . . . . . . . . 5		2. Countersignature Header Parameters . . . . . . . . . . . . . 5
	3. Version 2 Countersignatures . . . . . . . . . . . . . . . . . 6		3. Version 2 Countersignatures . . . . . . . . . . . . . . . . . 6
	3.1. Full Countersignatures . . . . . . . . . . . . . . . . . 7		3.1. Full Countersignatures . . . . . . . . . . . . . . . . . 7
	3.2. Abbreviated Countersignatures . . . . . . . . . . . . . . 8		3.2. Abbreviated Countersignatures . . . . . . . . . . . . . . 8
	3.3. Signing and Verification Process . . . . . . . . . . . . 8		3.3. Signing and Verification Process . . . . . . . . . . . . 8
	4. CBOR Encoding Restrictions . . . . . . . . . . . . . . . . . 10		4. CBOR Encoding Restrictions . . . . . . . . . . . . . . . . . 10
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
	5.1. CBOR Tag Assignment . . . . . . . . . . . . . . . . . . . 10		5.1. CBOR Tag Assignment . . . . . . . . . . . . . . . . . . . 10
	skipping to change at page 2, line 45 ¶		skipping to change at page 2, line 50 ¶
	8.2. Informative References . . . . . . . . . . . . . . . . . 15		8.2. Informative References . . . . . . . . . . . . . . . . . 15
	Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 16		Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 16
	A.1. Examples of Signed Messages . . . . . . . . . . . . . . . 17		A.1. Examples of Signed Messages . . . . . . . . . . . . . . . 17
	A.1.1. Countersignature . . . . . . . . . . . . . . . . . . 17		A.1.1. Countersignature . . . . . . . . . . . . . . . . . . 17
	A.2. Examples of Enveloped Messages . . . . . . . . . . . . . 18		A.2. Examples of Enveloped Messages . . . . . . . . . . . . . 18
	A.2.1. Countersignature on Encrypted Content . . . . . . . . 18		A.2.1. Countersignature on Encrypted Content . . . . . . . . 18
	A.3. Examples of Encrypted Messages . . . . . . . . . . . . . 19		A.3. Examples of Encrypted Messages . . . . . . . . . . . . . 19
	A.4. Examples of MACed Messages . . . . . . . . . . . . . . . 19		A.4. Examples of MACed Messages . . . . . . . . . . . . . . . 19
	A.5. Examples of MAC0 Messages . . . . . . . . . . . . . . . . 20		A.5. Examples of MAC0 Messages . . . . . . . . . . . . . . . . 20
	Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 20		Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 20
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 20		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
	1. Introduction		1. Introduction
	There has been an increased focus on small, constrained devices that		There has been an increased focus on small, constrained devices that
	make up the Internet of Things (IoT). One of the standards that has		make up the Internet of Things (IoT). One of the standards that has
	come out of this process is "Concise Binary Object Representation		come out of this process is "Concise Binary Object Representation
	(CBOR)" [I-D.ietf-cbor-7049bis]. CBOR extended the data model of the		(CBOR)" [I-D.ietf-cbor-7049bis]. CBOR extended the data model of the
	JavaScript Object Notation (JSON) [STD90] by allowing for binary		JavaScript Object Notation (JSON) [STD90] by allowing for binary
	data, among other changes. CBOR has been adopted by several of the		data, among other changes. CBOR has been adopted by several of the
	IETF working groups dealing with the IoT world as their encoding of		IETF working groups dealing with the IoT world as their encoding of
	skipping to change at page 3, line 46 ¶		skipping to change at page 3, line 46 ¶
	countersignature computation so that the cryptographic computed		countersignature computation so that the cryptographic computed
	values is included. The exception to this is the COSE_Signature		values is included. The exception to this is the COSE_Signature
	structure where there is no cryptographic computed value.		structure where there is no cryptographic computed value.
	The new algorithm is designed to produce the same countersignature		The new algorithm is designed to produce the same countersignature
	value in those cases where the cryptographic computed value was		value in those cases where the cryptographic computed value was
	already included. This means that for those structures the only		already included. This means that for those structures the only
	thing that would need to be done is to change the value of the header		thing that would need to be done is to change the value of the header
	parameter.		parameter.
	This document deprecates the existing pair of header parameters to
	hold a countersignature value. This document defines two new header
	parameters to hold countersignature values computed with the new
	algorithm. This document defines a new countersignature computation
	algorithm which always includes cryptographic computed values if they
	exist.
	1.1. Requirements Terminology		1.1. Requirements Terminology
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and		"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	"OPTIONAL" in this document are to be interpreted as described in BCP		"OPTIONAL" in this document are to be interpreted as described in BCP
	14 [RFC2119] [RFC8174] when, and only when, they appear in all		14 [RFC2119] [RFC8174] when, and only when, they appear in all
	capitals, as shown here.		capitals, as shown here.
	1.2. CBOR Grammar		1.2. CBOR Grammar
	skipping to change at page 5, line 30 ¶		skipping to change at page 5, line 23 ¶
	V2 countersignature: This header parameter holds one or more		V2 countersignature: This header parameter holds one or more
	countersignature values. Countersignatures provide a method of		countersignature values. Countersignatures provide a method of
	having a second party sign some data. The countersignature header		having a second party sign some data. The countersignature header
	parameter can occur as an unprotected attribute in any of the		parameter can occur as an unprotected attribute in any of the
	following structures: COSE_Sign1, COSE_Signature, COSE_Encrypt,		following structures: COSE_Sign1, COSE_Signature, COSE_Encrypt,
	COSE_recipient, COSE_Encrypt0, COSE_Mac, and COSE_Mac0. Details		COSE_recipient, COSE_Encrypt0, COSE_Mac, and COSE_Mac0. Details
	on version 2 countersignatures are found in Section 3.		on version 2 countersignatures are found in Section 3.
	+===========+=====+========================+==========+=============+		+===========+=====+========================+==========+=============+
	| Name |Label| Value Type | Value | Description |		|Name |Label|Value Type | Value | Description |
	| | | | Registry | |		| | | | Registry | |
	+===========+=====+========================+==========+=============+		+===========+=====+========================+==========+=============+
	| counter |TBD10|COSE_Countersignature / | | V2 counter |		|counter |TBD10|COSE_Countersignature / | | V2 counter |
	| signature | |[+ COSE_Countersignature| | signature |		|signature | |[+ COSE_Countersignature| | signature |
	| version 2 | | ] | | attribute |		|version 2 | |] | | attribute |
	+-----------+-----+------------------------+----------+-------------+		+-----------+-----+------------------------+----------+-------------+
	| counter |TBD11| COSE_Countersignature0 | | Abbreviated |		|counter |TBD11|COSE_Countersignature0 | | Abbreviated |
	|signature 0| | | | Counter |		|signature 0| | | | Counter |
	| version 2 | | | | signature |		|version 2 | | | | signature |
	| | | | | vesion 2 |		| | | | | vesion 2 |
	+-----------+-----+------------------------+----------+-------------+		+-----------+-----+------------------------+----------+-------------+
	Table 1: Common Header Parameters		Table 1: Common Header Parameters
	The CDDL fragment that represents the set of header parameters		The CDDL fragment that represents the set of header parameters
	defined in this section is given below. Each of the header		defined in this section is given below. Each of the header
	parameters is tagged as optional because they do not need to be in		parameters is tagged as optional because they do not need to be in
	every map; header parameters required in specific maps are discussed		every map; header parameters required in specific maps are discussed
	above.		above.
	skipping to change at page 11, line 14 ¶		skipping to change at page 11, line 14 ¶
	5.2. COSE Header Parameters Registry		5.2. COSE Header Parameters Registry
	IANA created a registry titled "COSE Header Parameters" as part of		IANA created a registry titled "COSE Header Parameters" as part of
	processing [RFC8152].		processing [RFC8152].
	IANA is requested to register the following new items in the		IANA is requested to register the following new items in the
	registry.		registry.
	+=================+=====+======================+========+================+		+=================+=====+======================+========+================+
	| Name |Label| Value Type | Value | Description |		|Name |Label|Value Type |Value |Description |
	| | | |Registry| |		| | | |Registry| |
	+=================+=====+======================+========+================+		+=================+=====+======================+========+================+
	|counter signature|TBD10|COSE_Countersignature | | V2 |		|counter signature|TBD10|COSE_Countersignature | |V2 |
	| version 2 | | / [+ | |countersignature|		|version 2 | |/ [+ | |countersignature|
	| | |COSE_Countersignature | | attribute |		| | |COSE_Countersignature | |attribute |
	| | | ] | | |		| | |] | | |
	+-----------------+-----+----------------------+--------+----------------+		+-----------------+-----+----------------------+--------+----------------+
	|Countersignature0|TBD11|COSE_Countersignature0| | Abbreviated |		|Countersignature0|TBD11|COSE_Countersignature0| |Abbreviated |
	| version 2 | | | | Counter |		|version 2 | | | |Counter |
	| | | | |signature vesion|		| | | | |signature vesion|
	| | | | | 2 |		| | | | |2 |
	+-----------------+-----+----------------------+--------+----------------+		+-----------------+-----+----------------------+--------+----------------+
	Table 2: New Common Header Parameters		Table 2: New Common Header Parameters
	IANA is requested to modify the Description field for "counter		IANA is requested to modify the Description field for "counter
	signature" and "CounterSignature0" to include the words "(Deprecated		signature" and "CounterSignature0" to include the words "(Deprecated
	by [[This Document]]".		by [[This Document]]".
	6. Security Considerations		6. Security Considerations
	skipping to change at page 15, line 19 ¶		skipping to change at page 15, line 19 ¶
	8.1. Normative References		8.1. Normative References
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	[I-D.ietf-cbor-7049bis]		[I-D.ietf-cbor-7049bis]
	Bormann, C. and P. Hoffman, "Concise Binary Object		Bormann, C. and P. Hoffman, "Concise Binary Object
	Representation (CBOR)", Work in Progress, Internet-Draft,		Representation (CBOR)", Work in Progress, Internet-Draft,
	draft-ietf-cbor-7049bis-14, June 16, 2020,		draft-ietf-cbor-7049bis-16, 30 September 2020,
	<https://tools.ietf.org/html/draft-ietf-cbor-7049bis-14>.		<https://tools.ietf.org/html/draft-ietf-cbor-7049bis-16>.
	[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC		[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
	2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,		2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
	May 2017, <https://www.rfc-editor.org/info/rfc8174>.		May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	[I-D.ietf-cose-rfc8152bis-algs]		[I-D.ietf-cose-rfc8152bis-algs]
	Schaad, J., "CBOR Object Signing and Encryption (COSE):		Schaad, J., "CBOR Object Signing and Encryption (COSE):
	Initial Algorithms", Work in Progress, Internet-Draft,		Initial Algorithms", Work in Progress, Internet-Draft,
	draft-ietf-cose-rfc8152bis-algs-11, July 1, 2020,		draft-ietf-cose-rfc8152bis-algs-12, 24 September 2020,
	<https://tools.ietf.org/html/draft-ietf-cose-rfc8152bis-		<https://tools.ietf.org/html/draft-ietf-cose-rfc8152bis-
	algs-11>.		algs-12>.
	8.2. Informative References		8.2. Informative References
	[RFC8610] Birkholz, H., Vigano, C., and C. Bormann, "Concise Data		[RFC8610] Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
	Definition Language (CDDL): A Notational Convention to		Definition Language (CDDL): A Notational Convention to
	Express Concise Binary Object Representation (CBOR) and		Express Concise Binary Object Representation (CBOR) and
	JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,		JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
	June 2019, <https://www.rfc-editor.org/info/rfc8610>.		June 2019, <https://www.rfc-editor.org/info/rfc8610>.
	[RFC8152] Schaad, J., "CBOR Object Signing and Encryption (COSE)",		[RFC8152] Schaad, J., "CBOR Object Signing and Encryption (COSE)",
	skipping to change at page 16, line 23 ¶		skipping to change at page 16, line 23 ¶
	<https://www.rfc-editor.org/info/rfc7942>.		<https://www.rfc-editor.org/info/rfc7942>.
	[RFC4998] Gondrom, T., Brandner, R., and U. Pordesch, "Evidence		[RFC4998] Gondrom, T., Brandner, R., and U. Pordesch, "Evidence
	Record Syntax (ERS)", RFC 4998, DOI 10.17487/RFC4998,		Record Syntax (ERS)", RFC 4998, DOI 10.17487/RFC4998,
	August 2007, <https://www.rfc-editor.org/info/rfc4998>.		August 2007, <https://www.rfc-editor.org/info/rfc4998>.
	[I-D.ietf-core-groupcomm-bis]		[I-D.ietf-core-groupcomm-bis]
	Dijk, E., Wang, C., and M. Tiloca, "Group Communication		Dijk, E., Wang, C., and M. Tiloca, "Group Communication
	for the Constrained Application Protocol (CoAP)", Work in		for the Constrained Application Protocol (CoAP)", Work in
	Progress, Internet-Draft, draft-ietf-core-groupcomm-bis-		Progress, Internet-Draft, draft-ietf-core-groupcomm-bis-
	01, July 13, 2020, <https://tools.ietf.org/html/draft-		01, 13 July 2020, <https://tools.ietf.org/html/draft-ietf-
	ietf-core-groupcomm-bis-01>.		core-groupcomm-bis-01>.
	[I-D.ietf-cose-rfc8152bis-struct]		[I-D.ietf-cose-rfc8152bis-struct]
	Schaad, J., "CBOR Object Signing and Encryption (COSE):		Schaad, J., "CBOR Object Signing and Encryption (COSE):
	Structures and Process", Work in Progress, Internet-Draft,		Structures and Process", Work in Progress, Internet-Draft,
	draft-ietf-cose-rfc8152bis-struct-12, August 24, 2020,		draft-ietf-cose-rfc8152bis-struct-13, 4 September 2020,
	<https://tools.ietf.org/html/draft-ietf-cose-rfc8152bis-		<https://tools.ietf.org/html/draft-ietf-cose-rfc8152bis-
	struct-12>.		struct-13>.
	[RFC8613] Selander, G., Mattsson, J., Palombini, F., and L. Seitz,		[RFC8613] Selander, G., Mattsson, J., Palombini, F., and L. Seitz,
	"Object Security for Constrained RESTful Environments		"Object Security for Constrained RESTful Environments
	(OSCORE)", RFC 8613, DOI 10.17487/RFC8613, July 2019,		(OSCORE)", RFC 8613, DOI 10.17487/RFC8613, July 2019,
	<https://www.rfc-editor.org/info/rfc8613>.		<https://www.rfc-editor.org/info/rfc8613>.
	Appendix A. Examples		Appendix A. Examples
	This appendix includes a set of examples that show the different		This appendix includes a set of examples that show the different
	features and message types that have been defined in this document.		features and message types that have been defined in this document.
	skipping to change at page 20, line 13 ¶		skipping to change at page 20, line 13 ¶
	A.4. Examples of MACed Messages		A.4. Examples of MACed Messages
	A.5. Examples of MAC0 Messages		A.5. Examples of MAC0 Messages
	Acknowledgments		Acknowledgments
	This document is a product of the COSE working group of the IETF.		This document is a product of the COSE working group of the IETF.
	The initial version of the specification was based to some degree on		The initial version of the specification was based to some degree on
	the outputs of the JOSE and S/MIME working groups.		the outputs of the JOSE and S/MIME working groups.
	Author's Address		Jim Schaad passed on 3 October 2020. This document is primarily his
			work. Russ Housley served as the document editor after Jim's
			untimely death, mostly helping with the approval and publication
			processes. Jim deserves all credit for the technical content.
			{{{ RFC EDITOR: Please remove Russ Housley as an author of this
			document at publication. Jim Schaad should be listed as the sole
			author. }}}
			Authors' Addresses
	Jim Schaad		Jim Schaad
	August Cellars		August Cellars
	Email: ietf@augustcellars.com		Email: ietf@augustcellars.com
			Russ Housley (editor)
			Vigil Security, LLC
			Email: housley@vigilsec.com
End of changes. 23 change blocks.
	37 lines changed or deleted		40 lines changed or added
This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/