draft-ietf-cose-hash-algs-02.txt		draft-ietf-cose-hash-algs-03.txt
	Network Working Group J. Schaad		Network Working Group J. Schaad
	Internet-Draft August Cellars		Internet-Draft August Cellars
	Intended status: Informational 4 November 2019		Intended status: Informational 9 March 2020
	Expires: 7 May 2020		Expires: 10 September 2020
	CBOR Object Signing and Encryption (COSE): Hash Algorithms		CBOR Object Signing and Encryption (COSE): Hash Algorithms
	draft-ietf-cose-hash-algs-02		draft-ietf-cose-hash-algs-03
	Abstract		Abstract
	The CBOR Object Signing and Encryption (COSE) syntax		The CBOR Object Signing and Encryption (COSE) syntax
	[I-D.ietf-cose-rfc8152bis-struct] does not define any direct methods		[I-D.ietf-cose-rfc8152bis-struct] does not define any direct methods
	for using hash algorithms. There are however circumstances where		for using hash algorithms. There are however circumstances where
	hash algorithms are used: Indirect signatures where the hash of one		hash algorithms are used: Indirect signatures where the hash of one
	or more contents are signed. X.509 certificate or other object		or more contents are signed. X.509 certificate or other object
	identification by the use of a thumbprint. This document defines a		identification by the use of a fingerprint. This document defines a
	set of hash algorithms that are identified by COSE Algorithm		set of hash algorithms that are identified by COSE Algorithm
	Identifiers.		Identifiers.
	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/X509 Editorial changes can be managed in GitHub, but any		cose-wg/X509 Editorial changes can be managed in GitHub, but any
	skipping to change at page 1, line 46 ¶		skipping to change at page 1, line 46 ¶
	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 7 May 2020.		This Internet-Draft will expire on 10 September 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 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 . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	1.1. Requirements Terminology . . . . . . . . . . . . . . . . 3		1.1. Requirements Terminology . . . . . . . . . . . . . . . . 3
	1.2. Open Issues . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Hash Algorithm Usage . . . . . . . . . . . . . . . . . . . . 3		2. Hash Algorithm Usage . . . . . . . . . . . . . . . . . . . . 3
	2.1. Example CBOR hash structure . . . . . . . . . . . . . . . 4		2.1. Example CBOR hash structure . . . . . . . . . . . . . . . 4
	3. Hash Algorithm Identifiers . . . . . . . . . . . . . . . . . 5		3. Hash Algorithm Identifiers . . . . . . . . . . . . . . . . . 5
	3.1. SHA-1 Hash Algorithm . . . . . . . . . . . . . . . . . . 5		3.1. SHA-1 Hash Algorithm . . . . . . . . . . . . . . . . . . 5
	3.2. SHA-2 Hash Algorithms . . . . . . . . . . . . . . . . . . 6		3.2. SHA-2 Hash Algorithms . . . . . . . . . . . . . . . . . . 6
	3.3. SHAKE Algorithms . . . . . . . . . . . . . . . . . . . . 7		3.3. SHAKE Algorithms . . . . . . . . . . . . . . . . . . . . 7
	4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8		4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
	4.1. COSE Algorithm Registry . . . . . . . . . . . . . . . . . 8		4.1. COSE Algorithm Registry . . . . . . . . . . . . . . . . . 8
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 8		5. Security Considerations . . . . . . . . . . . . . . . . . . . 8
	6. Normative References . . . . . . . . . . . . . . . . . . . . 9		6. Normative References . . . . . . . . . . . . . . . . . . . . 9
	7. Informative References . . . . . . . . . . . . . . . . . . . 9		7. Informative References . . . . . . . . . . . . . . . . . . . 10
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10		Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10
	1. Introduction		1. Introduction
	The CBOR Object Signing and Encryption (COSE) syntax does not define		The CBOR Object Signing and Encryption (COSE) syntax does not define
	any direct methods for the use of hash algorithms. It also does not		any direct methods for the use of hash algorithms. It also does not
	define a structure syntax that is used to encode a digested object		define a structure syntax that is used to encode a digested object
	structure along the lines of the DigestedData ASN.1 structure in		structure along the lines of the DigestedData ASN.1 structure in
	[CMS]. This omission was intentional as a structure consisting of		[CMS]. This omission was intentional as a structure consisting of
	just a digest identifier, the content, and a digest value does not by		just a digest identifier, the content, and a digest value does not by
	skipping to change at page 3, line 34 ¶		skipping to change at page 3, line 32 ¶
	[I-D.ietf-cose-x509].		[I-D.ietf-cose-x509].
	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. Open Issues
	This section is to be removed before publishing as an RFC.
	* No Open Issues
	2. Hash Algorithm Usage		2. Hash Algorithm Usage
	As noted in the previous section, hash functions can be used for a		As noted in the previous section, hash functions can be used for a
	variety of purposes. Some of these purposes require that a hash		variety of purposes. Some of these purposes require that a hash
	function be cryptographically strong, these include direct and		function be cryptographically strong, these include direct and
	indirect signatures. That is, using the hash as part of the		indirect signatures. That is, using the hash as part of the
	signature or using the hash as part of the body to be signed. Other		signature or using the hash as part of the body to be signed. Other
	uses of hash functions do not require the same level of strength.		uses of hash functions do not require the same level of strength.
	This document contains some hash functions that are not designed to		This document contains some hash functions that are not designed to
	skipping to change at page 4, line 27 ¶		skipping to change at page 4, line 18 ¶
	used is when there is absolutely no other choice (e.g. a Hardware		used is when there is absolutely no other choice (e.g. a Hardware
	Security Module (HSM) that cannot be replaced), and only after		Security Module (HSM) that cannot be replaced), and only after
	looking at the possible security issues. Cryptographic purposes		looking at the possible security issues. Cryptographic purposes
	would include the creation of signatures or the use of hashes for		would include the creation of signatures or the use of hashes for
	indirect signatures. These functions may still be usable for non-		indirect signatures. These functions may still be usable for non-
	cryptographic purposes.		cryptographic purposes.
	An example of a non-cryptographic use of a hash is for filtering from		An example of a non-cryptographic use of a hash is for filtering from
	a collection of values to find possible candidates that can later be		a collection of values to find possible candidates that can later be
	checked to see if they are the correct one. A simple example of this		checked to see if they are the correct one. A simple example of this
	is the classic thumbprint of a certificate. If the thumbprint is		is the classic fingerprint of a certificate. If the fingerprint is
	used to verify that it is the correct certificate, then that usage is		used to verify that it is the correct certificate, then that usage is
	subject to a collision attack as above. If however, the thumbprint		subject to a collision attack as above. If however, the fingerprint
	is used to sort through a collection of certificates to find those		is used to sort through a collection of certificates to find those
	that might be used for the purpose of verifying a signature, a simple		that might be used for the purpose of verifying a signature, a simple
	filter capability is sufficient. In this case, one still needs to		filter capability is sufficient. In this case, one still needs to
	validate that the public key validates the signature (and the		validate that the public key validates the signature (and the
	certificate is trusted), and all certificates that don't contain a		certificate is trusted), and all certificates that don't contain a
	key that validates the signature can be discarded as false positives.		key that validates the signature can be discarded as false positives.
	To distinguish between these two cases, a new value in the		To distinguish between these two cases, a new value in the
	recommended column of the COSE Algorithms registry is to be added.		recommended column of the COSE Algorithms registry is to be added.
	"Filter Only" indicates that the only purpose of a hash function		"Filter Only" indicates that the only purpose of a hash function
	skipping to change at page 5, line 13 ¶		skipping to change at page 5, line 6 ¶
	* The hash algorithm identifier.		* The hash algorithm identifier.
	* The hash value.		* The hash value.
	* A pointer to the value that was hashed, this could be a pointer to		* A pointer to the value that was hashed, this could be a pointer to
	a file, an object that can be obtained from the network, or a		a file, an object that can be obtained from the network, or a
	pointer to someplace in the message, or something very application		pointer to someplace in the message, or something very application
	specific.		specific.
	* Additional data, this can be something as simple as a random value		* Additional data, this can be something as simple as a random value
	to make finding hash collisions slightly harder as the value		to make finding hash collisions slightly harder (as the value
	handed to the application cannot have been selected to have a		handed to the application cannot have been selected to have a
	collision, or as complicated as a set of processing instructions		collision), or as complicated as a set of processing instructions
	that are used with the object that is pointed to. The additional		that are used with the object that is pointed to. The additional
	data can be dealt with in a number of ways, prepending or		data can be dealt with in a number of ways, prepending or
	appending to the content, but it is strongly suggested to it		appending to the content, but it is strongly suggested to it
	either be a fixed known size, or the lengths of the pieces being		either be a fixed known size, or the lengths of the pieces being
	hashed be included. (Encoding as a CBOR array accomplished this		hashed be included. (Encoding as a CBOR array accomplished this
	requirement.)		requirement.)
	An example of a structure which permits all of the above fields to		An example of a structure which permits all of the above fields to
	exist would look like the following.		exist would look like the following.
	COSE_Hash_V = ( 1 : int / tstr, # Algorithm identifier 2 : bstr, # Hash value 3 : tstr ?, # Location of object hashed 4 : any ? # object containing other details and things )		COSE_Hash_V = (
			1 : int / tstr, # Algorithm identifier
			2 : bstr, # Hash value
			3 : tstr ?, # Location of object hashed
			4 : any ? # object containing other details and things
			)
	An alternate structure that could be used for situations where one is		An alternate structure that could be used for situations where one is
	searching a group of objects for a match. In this case, the location		searching a group of objects for a match. In this case, the location
	would not be needed and adding extra data to the hash would be		would not be needed and adding extra data to the hash would be
	counterproductive. This results in a structure that looks like this:		counterproductive. This results in a structure that looks like this:
	COSE_Hash_Find = [ hashAlg : int / tstr, hashValue : bstr ]		COSE_Hash_Find = [
			hashAlg : int / tstr,
			hashValue : bstr
			]
	3. Hash Algorithm Identifiers		3. Hash Algorithm Identifiers
	3.1. SHA-1 Hash Algorithm		3.1. SHA-1 Hash Algorithm
	The SHA-1 hash algorithm [RFC3174] was designed by the United States		The SHA-1 hash algorithm [RFC3174] was designed by the United States
	National Security Agency and published in 1995. Since that time a		National Security Agency and published in 1995. Since that time a
	large amount of cryptographic analysis has been applied to this		large amount of cryptographic analysis has been applied to this
	algorithm and a successful collision attack has been created		algorithm and a successful collision attack has been created
	([SHA-1-collision]). The IETF formally started discouraging the use		([SHA-1-collision]). The IETF formally started discouraging the use
	skipping to change at page 6, line 9 ¶		skipping to change at page 6, line 9 ¶
	and therefore it makes sense to assign a point for the use of this		and therefore it makes sense to assign a point for the use of this
	hash algorithm. Some of these situations are with historic HSMs		hash algorithm. Some of these situations are with historic HSMs
	where only SHA-1 is implemented or where the SHA-1 value is used for		where only SHA-1 is implemented or where the SHA-1 value is used for
	the purpose of filtering and thus the collision resistance property		the purpose of filtering and thus the collision resistance property
	is not needed.		is not needed.
	Because of the known issues for SHA-1 and the fact that is should no		Because of the known issues for SHA-1 and the fact that is should no
	longer be used, the algorithm will be registered with the		longer be used, the algorithm will be registered with the
	recommendation of "Filter Only".		recommendation of "Filter Only".
	+-------+-------+-------------+-----------------+-------------+		The COSE capabilities for this algorithm is an empty array.
	| Name | Value | Description | Reference | Recommended |
	+=======+=======+=============+=================+=============+		+-----+------+-------------+--------------+-----------+-------------+
	| SHA-1 | TBD6 | SHA-1 Hash | [This Document] | Filter Only |		|Name |Value | Description | Capabilities | Reference | Recommended |
	+-------+-------+-------------+-----------------+-------------+		+=====+======+=============+==============+===========+=============+
			|SHA-1| TBD6 | SHA-1 Hash | [] | [This | Filter Only |
			| | | | | Document] | |
			+-----+------+-------------+--------------+-----------+-------------+
	Table 1: SHA-1 Hash Algorithm		Table 1: SHA-1 Hash Algorithm
	3.2. SHA-2 Hash Algorithms		3.2. SHA-2 Hash Algorithms
	The family of SHA-2 hash algorithms [FIPS-180-4] was designed by the		The family of SHA-2 hash algorithms [FIPS-180-4] was designed by the
	United States National Security Agency and published in 2001. Since		United States National Security Agency and published in 2001. Since
	that time some additional algorithms have been added to the original		that time some additional algorithms have been added to the original
	set to deal with length extension attacks and some performance		set to deal with length extension attacks and some performance
	issues. While the SHA-3 hash algorithms have been published since		issues. While the SHA-3 hash algorithms have been published since
	skipping to change at page 7, line 5 ¶		skipping to change at page 7, line 9 ¶
	currently. SHA-256 is an efficient hash algorithm for 32-bit		currently. SHA-256 is an efficient hash algorithm for 32-bit
	hardware.		hardware.
	* *SHA-384* and *SHA-512* hash functions are efficient for 64-bit		* *SHA-384* and *SHA-512* hash functions are efficient for 64-bit
	hardware.		hardware.
	* *SHA-512/256* provides a hash function that runs more efficiently		* *SHA-512/256* provides a hash function that runs more efficiently
	on 64-bit hardware, but offers the same security levels as SHA-		on 64-bit hardware, but offers the same security levels as SHA-
	256.		256.
	+-------------+-------+----------------+-----------+-------------+		The COSE capabilities for these algorithms is an empty array.
	| Name | Value | Description | Reference | Recommended |
	+=============+=======+================+===========+=============+
	| SHA-256/64 | TBD1 | SHA-2 256-bit | [This | Filter Only |
	| | | Hash truncated | Document] | |
	| | | to 64-bits | | |
	+-------------+-------+----------------+-----------+-------------+
	| SHA-256 | TBD2 | SHA-2 256-bit | [This | Yes |
	| | | Hash | Document] | |
	+-------------+-------+----------------+-----------+-------------+
	| SHA-384 | TBD3 | SHA-2 384-bit | [This | Yes |
	| | | Hash | Document] | |
	+-------------+-------+----------------+-----------+-------------+
	| SHA-512 | TBD4 | SHA-2 512-bit | [This | Yes |
	| | | Hash | Document] | |
	+-------------+-------+----------------+-----------+-------------+
	| SHA-512/256 | TBD5 | SHA-2 512-bit | [This | Yes |
	| | | Hash truncated | Document] | |
	| | | to 256-bits | | |
	+-------------+-------+----------------+-----------+-------------+
	Table 2: SHA-2 Hash Algorithms		+-----------+-----+-----------+--------------+---------+------------+
			| Name |Value|Description| Capabilities |Reference|Recommended |
			+===========+=====+===========+==============+=========+============+
			|SHA-256/64 |TBD1 | SHA-2 | [] | [This |Filter Only |
			| | | 256-bit | |Document]| |
			| | | Hash | | | |
			| | | truncated | | | |
			| | |to 64-bits | | | |
			+-----------+-----+-----------+--------------+---------+------------+
			| SHA-256 |TBD2 | SHA-2 | [] | [This | Yes |
			| | | 256-bit | |Document]| |
			| | | Hash | | | |
			+-----------+-----+-----------+--------------+---------+------------+
			| SHA-384 |TBD3 | SHA-2 | [] | [This | Yes |
			| | | 384-bit | |Document]| |
			| | | Hash | | | |
			+-----------+-----+-----------+--------------+---------+------------+
			| SHA-512 |TBD4 | SHA-2 | [] | [This | Yes |
			| | | 512-bit | |Document]| |
			| | | Hash | | | |
			+-----------+-----+-----------+--------------+---------+------------+
			|SHA-512/256|TBD5 | SHA-2 | [] | [This | Yes |
			| | | 512-bit | |Document]| |
			| | | Hash | | | |
			| | | truncated | | | |
			| | |to 256-bits| | | |
			+-----------+-----+-----------+--------------+---------+------------+
			Table 2: SHA-2 Hash Algorithms
	3.3. SHAKE Algorithms		3.3. SHAKE Algorithms
	The family SHA-3 hash algorithms [FIPS-202] was the result of a		The family SHA-3 hash algorithms [FIPS-202] was the result of a
	competition run by NIST. The pair of algorithms known as SHAKE-128		competition run by NIST. The pair of algorithms known as SHAKE-128
	and SHAKE-256 are the instances of SHA-3 that are currently being		and SHAKE-256 are the instances of SHA-3 that are currently being
	standardized in the IETF.		standardized in the IETF.
	The SHA-3 hash algorithms have a significantly different structure		The SHA-3 hash algorithms have a significantly different structure
	than the SHA-2 hash algorithms. One of the benefits of this		than the SHA-2 hash algorithms. One of the benefits of this
	differences is that when computing a shorter SHAKE hash value, the		differences is that when computing a shorter SHAKE hash value, the
	value is not a prefix of the result of computing the longer hash.		value is not a prefix of the result of computing the longer hash.
	Unlike the SHA-2 hash functions, no algorithm identifier is created		Unlike the SHA-2 hash functions, no algorithm identifier is created
	for shorter lengths. Applications can specify a minimum length for		for shorter lengths. Applications can specify a minimum length for
	any hash function. A validator can infer the actual length from the		any hash function. A validator can infer the actual length from the
	hash value in these cases.		hash value in these cases.
	+----------+-------+---------------+-----------------+-------------+		The COSE capabilities for these algorithms is an empty array.
	| Name | Value | Description | Reference | Recommended |
	+==========+=======+===============+=================+=============+
	| SHAKE128 | TBD10 | 128-bit SHAKE | [This Document] | Yes |
	+----------+-------+---------------+-----------------+-------------+
	| SHAKE256 | TBD11 | 256-bit SHAKE | [This Document] | Yes |
	+----------+-------+---------------+-----------------+-------------+
	Table 3: SHAKE Hash Functions		+--------+-----+-------------+--------------+---------+-------------+
			| Name |Value| Description | Capabilities |Reference| Recommended |
			+========+=====+=============+==============+=========+=============+
			|SHAKE128|TBD10|128-bit SHAKE| [] | [This | Yes |
			| | | | |Document]| |
			+--------+-----+-------------+--------------+---------+-------------+
			|SHAKE256|TBD11|256-bit SHAKE| [] | [This | Yes |
			| | | | |Document]| |
			+--------+-----+-------------+--------------+---------+-------------+
			Table 3: SHAKE Hash Functions
	4. IANA Considerations		4. IANA Considerations
	4.1. COSE Algorithm Registry		4.1. COSE Algorithm Registry
	IANA is requested to register the following algorithms in the "COSE		IANA is requested to register the following algorithms in the "COSE
	Algorithms" registry.		Algorithms" registry.
	* The SHA-1 hash function found in Table 1.		* The SHA-1 hash function found in Table 1.
	skipping to change at page 9, line 28 ¶		skipping to change at page 9, line 39 ¶
	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>.
	[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-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-06, 11 September 2019,		draft-ietf-cose-rfc8152bis-struct-07, 17 November 2019,
	<https://tools.ietf.org/html/draft-ietf-cose-rfc8152bis-		<https://tools.ietf.org/html/draft-ietf-cose-rfc8152bis-
	struct-06>.		struct-07>.
	[FIPS-180-4]		[FIPS-180-4]
	National Institute of Standards and Technology, "Secure		National Institute of Standards and Technology, "Secure
	Hash Standard", FIPS PUB 180-4, August 2015.		Hash Standard", FIPS PUB 180-4, August 2015.
	[FIPS-202] National Institute of Standards and Technology, "SHA-3		[FIPS-202] National Institute of Standards and Technology, "SHA-3
	Standard: Permutation-Based Hash and Extendable-Output		Standard: Permutation-Based Hash and Extendable-Output
	Functions", FIPS PUB 202, August 2015.		Functions", FIPS PUB 202, August 2015.
	[COSE] Schaad, J., "CBOR Object Signing and Encryption (COSE)",		[COSE] Schaad, J., "CBOR Object Signing and Encryption (COSE)",
	skipping to change at page 10, line 10 ¶		skipping to change at page 10, line 20 ¶
	RFC 5652, DOI 10.17487/RFC5652, September 2009,		RFC 5652, DOI 10.17487/RFC5652, September 2009,
	<https://www.rfc-editor.org/info/rfc5652>.		<https://www.rfc-editor.org/info/rfc5652>.
	[ESS] Hoffman, P., Ed., "Enhanced Security Services for S/MIME",		[ESS] Hoffman, P., Ed., "Enhanced Security Services for S/MIME",
	RFC 2634, DOI 10.17487/RFC2634, June 1999,		RFC 2634, DOI 10.17487/RFC2634, June 1999,
	<https://www.rfc-editor.org/info/rfc2634>.		<https://www.rfc-editor.org/info/rfc2634>.
	[I-D.ietf-cose-x509]		[I-D.ietf-cose-x509]
	Schaad, J., "CBOR Object Signing and Encryption (COSE):		Schaad, J., "CBOR Object Signing and Encryption (COSE):
	Headers for carrying and referencing X.509 certificates",		Headers for carrying and referencing X.509 certificates",
	Work in Progress, Internet-Draft, draft-ietf-cose-x509-04,		Work in Progress, Internet-Draft, draft-ietf-cose-x509-05,
	12 September 2019,		4 November 2019,
	<https://tools.ietf.org/html/draft-ietf-cose-x509-04>.		<https://tools.ietf.org/html/draft-ietf-cose-x509-05>.
	[RFC3174] Eastlake 3rd, D. and P. Jones, "US Secure Hash Algorithm 1		[RFC3174] Eastlake 3rd, D. and P. Jones, "US Secure Hash Algorithm 1
	(SHA1)", RFC 3174, DOI 10.17487/RFC3174, September 2001,		(SHA1)", RFC 3174, DOI 10.17487/RFC3174, September 2001,
	<https://www.rfc-editor.org/info/rfc3174>.		<https://www.rfc-editor.org/info/rfc3174>.
	[RFC6194] Polk, T., Chen, L., Turner, S., and P. Hoffman, "Security		[RFC6194] Polk, T., Chen, L., Turner, S., and P. Hoffman, "Security
	Considerations for the SHA-0 and SHA-1 Message-Digest		Considerations for the SHA-0 and SHA-1 Message-Digest
	Algorithms", RFC 6194, DOI 10.17487/RFC6194, March 2011,		Algorithms", RFC 6194, DOI 10.17487/RFC6194, March 2011,
	<https://www.rfc-editor.org/info/rfc6194>.		<https://www.rfc-editor.org/info/rfc6194>.
End of changes. 22 change blocks.
	59 lines changed or deleted		76 lines changed or added
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