draft-ietf-lamps-cms-update-alg-id-protect-04.txt		draft-ietf-lamps-cms-update-alg-id-protect-05.txt
	Network Working Group R. Housley		Network Working Group R. Housley
	Internet-Draft Vigil Security		Internet-Draft Vigil Security
	Updates: 5652 (if approved) August 27, 2020		Updates: 5652 (if approved) August 27, 2020
	Intended status: Standards Track		Intended status: Standards Track
	Expires: February 28, 2021		Expires: February 28, 2021
	Update to the Cryptographic Message Syntax (CMS) for Algorithm		Update to the Cryptographic Message Syntax (CMS) for Algorithm
	Identifier Protection		Identifier Protection
	draft-ietf-lamps-cms-update-alg-id-protect-04		draft-ietf-lamps-cms-update-alg-id-protect-05
	Abstract		Abstract
	This document updates the Cryptographic Message Syntax (CMS)		This document updates the Cryptographic Message Syntax (CMS)
	specified in RFC 5652 to ensure that algorithm identifiers in signed-		specified in RFC 5652 to ensure that algorithm identifiers in signed-
	data and authenticated-data content types are adequately protected.		data and authenticated-data content types are adequately protected.
	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
	skipping to change at page 2, line 15 ¶		skipping to change at page 2, line 15 ¶
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
	3. Required use the same hash algorithm . . . . . . . . . . . . 3		3. Required use the same hash algorithm . . . . . . . . . . . . 3
	3.1. RFC 5652, Section 5.3 . . . . . . . . . . . . . . . . . . 3		3.1. RFC 5652, Section 5.3 . . . . . . . . . . . . . . . . . . 3
	3.2. RFC 5652, Section 5.4 . . . . . . . . . . . . . . . . . . 4		3.2. RFC 5652, Section 5.4 . . . . . . . . . . . . . . . . . . 4
	3.3. RFC 5652, Section 5.6 . . . . . . . . . . . . . . . . . . 4		3.3. RFC 5652, Section 5.6 . . . . . . . . . . . . . . . . . . 4
	3.4. Backward Compatibility Considerations . . . . . . . . . . 5		3.4. Backward Compatibility Considerations . . . . . . . . . . 5
	3.5. Timestamp Compatibility Considerations . . . . . . . . . 5		3.5. Timestamp Compatibility Considerations . . . . . . . . . 5
	4. Recommended inclusion of the CMSAlgorithmProtection attribute 6		4. Recommended inclusion of the CMSAlgorithmProtection attribute 5
	4.1. RFC 5652, Section 14 . . . . . . . . . . . . . . . . . . 6		4.1. RFC 5652, Section 14 . . . . . . . . . . . . . . . . . . 6
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
	6. Security Considerations . . . . . . . . . . . . . . . . . . . 6		6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
	7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7		7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7		8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
	8.1. Normative References . . . . . . . . . . . . . . . . . . 7		8.1. Normative References . . . . . . . . . . . . . . . . . . 7
	8.2. Informative References . . . . . . . . . . . . . . . . . 8		8.2. Informative References . . . . . . . . . . . . . . . . . 8
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 9		Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
	1. Introduction		1. Introduction
	This document updates the Cryptographic Message Syntax (CMS)		This document updates the Cryptographic Message Syntax (CMS)
	[RFC5652] to ensure that algorithm identifiers in signed-data and		[RFC5652] to ensure that algorithm identifiers in signed-data and
	authenticated-data content types are adequately protected.		authenticated-data content types are adequately protected.
	The CMS signed-data Content Type [RFC5652], unlike X.509 certificates		The CMS signed-data Content Type [RFC5652], unlike X.509 certificates
	[RFC5280], can be vulnerable to algorithm substitution attacks. In		[RFC5280], can be vulnerable to algorithm substitution attacks. In
	an algorithm substitution attack, the attacker changes either the		an algorithm substitution attack, the attacker changes either the
	skipping to change at page 4, line 38 ¶		skipping to change at page 4, line 38 ¶
	Add the following paragraph as the second paragraph in Section 5.4:		Add the following paragraph as the second paragraph in Section 5.4:
	ADD:		ADD:
	When the signedAttrs field is present, the same digest algorithm		When the signedAttrs field is present, the same digest algorithm
	MUST be used to compute the digest of the encapContentInfo		MUST be used to compute the digest of the encapContentInfo
	eContent OCTET STRING, which is carried in the message-digest		eContent OCTET STRING, which is carried in the message-digest
	attribute, and the digest of the collection of attributes that are		attribute, and the digest of the collection of attributes that are
	signed.		signed.
	nit: there may be a grammar nit here, relating to the parallelism of
	"compute the digest of" - I think "the collection of attributes that
	are signed" should also have an "of" or "digest of" prefix.
	3.3. RFC 5652, Section 5.6		3.3. RFC 5652, Section 5.6
	Change the paragraph discussing the signed attributes as follows:		Change the paragraph discussing the signed attributes as follows:
	OLD:		OLD:
	The recipient MUST NOT rely on any message digest values computed		The recipient MUST NOT rely on any message digest values computed
	by the originator. If the SignedData signerInfo includes		by the originator. If the SignedData signerInfo includes
	signedAttributes, then the content message digest MUST be		signedAttributes, then the content message digest MUST be
	calculated as described in Section 5.4. For the signature to be		calculated as described in Section 5.4. For the signature to be
End of changes. 4 change blocks.
	7 lines changed or deleted		3 lines changed or added
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