draft-ietf-curdle-rsa-sha2-12.txt		rfc8332.txt
	Internet-Draft D. Bider		Internet Engineering Task Force (IETF) D. Bider
	Updates: 4252, 4253 (if approved) Bitvise Limited		Request for Comments: 8332 Bitvise Limited
	Intended status: Standards Track October 12, 2017		Updates: 4252, 4253 March 2018
	Expires: April 12, 2018		Category: Standards Track
			ISSN: 2070-1721
	Use of RSA Keys with SHA-256 and SHA-512 in Secure Shell (SSH)		Use of RSA Keys with SHA-256 and SHA-512
	draft-ietf-curdle-rsa-sha2-12.txt		in the Secure Shell (SSH) Protocol
	Abstract		Abstract
	This memo updates RFC 4252 and RFC 4253 to define new public key		This memo updates RFCs 4252 and 4253 to define new public key
	algorithms for use of RSA keys with SHA-256 and SHA-512 for server and		algorithms for use of RSA keys with SHA-256 and SHA-512 for server
	client authentication in SSH connections.		and client authentication in SSH connections.
	Status		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This is an Internet Standards Track document.
	provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering Task		This document is a product of the Internet Engineering Task Force
	Force (IETF), its areas, and its working groups. Note that other		(IETF). It represents the consensus of the IETF community. It has
	groups may also distribute working documents as Internet-Drafts.		received public review and has been approved for publication by the
			Internet Engineering Steering Group (IESG). Further information on
			Internet Standards is available in Section 2 of RFC 7841.
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	time. It is inappropriate to use Internet-Drafts as reference material		https://www.rfc-editor.org/info/rfc8332.
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	Copyright (c) 2017 IETF Trust and the persons identified as the		This document may contain material from IETF Documents or IETF
	document authors. All rights reserved.		Contributions published or made publicly available before November
			10, 2008. The person(s) controlling the copyright in some of this
			material may not have granted the IETF Trust the right to allow
			modifications of such material outside the IETF Standards Process.
			Without obtaining an adequate license from the person(s) controlling
			the copyright in such materials, this document may not be modified
			outside the IETF Standards Process, and derivative works of it may
			not be created outside the IETF Standards Process, except to format
			it for publication as an RFC or to translate it into languages other
			than English.
	This document is subject to BCP 78 and the IETF Trust's Legal		Table of Contents
	Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents
	carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.
	This document may contain material from IETF Documents or IETF		1. Overview and Rationale . . . . . . . . . . . . . . . . . . . 3
	Contributions published or made publicly available before November 10,		1.1. Requirements Terminology . . . . . . . . . . . . . . . . 3
	2008. The person(s) controlling the copyright in some of this material		1.2. Wire Encoding Terminology . . . . . . . . . . . . . . . . 3
	may not have granted the IETF Trust the right to allow modifications		2. Public Key Format vs. Public Key Algorithm . . . . . . . . . 3
	of such material outside the IETF Standards Process. Without obtaining		3. New RSA Public Key Algorithms . . . . . . . . . . . . . . . . 4
	an adequate license from the person(s) controlling the copyright in		3.1. Use for Server Authentication . . . . . . . . . . . . . . 5
	such materials, this document may not be modified outside the IETF		3.2. Use for Client Authentication . . . . . . . . . . . . . . 5
	Standards Process, and derivative works of it may not be created		3.3. Discovery of Public Key Algorithms Supported by Servers . 6
	outside the IETF Standards Process, except to format it for		4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
	publication as an RFC or to translate it into languages other than		5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
	English.		5.1. Key Size and Signature Hash . . . . . . . . . . . . . . . 7
			5.2. Transition . . . . . . . . . . . . . . . . . . . . . . . 7
			5.3. PKCS #1 v1.5 Padding and Signature Verification . . . . . 7
			6. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
			6.1. Normative References . . . . . . . . . . . . . . . . . . 8
			6.2. Informative References . . . . . . . . . . . . . . . . . 8
			Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 9
			Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 9
	1. Overview and Rationale		1. Overview and Rationale
	Secure Shell (SSH) is a common protocol for secure communication on		Secure Shell (SSH) is a common protocol for secure communication on
	the Internet. In [RFC4253], SSH originally defined the public key		the Internet. In [RFC4253], SSH originally defined the public key
	algorithms "ssh-rsa" for server and client authentication using RSA		algorithms "ssh-rsa" for server and client authentication using RSA
	with SHA-1, and "ssh-dss" using 1024-bit DSA and SHA-1. These		with SHA-1, and "ssh-dss" using 1024-bit DSA and SHA-1. These
	algorithms are now considered deficient. For US government use, NIST		algorithms are now considered deficient. For US government use, NIST
	has disallowed 1024-bit RSA and DSA, and use of SHA-1 for signing		has disallowed 1024-bit RSA and DSA, and use of SHA-1 for signing
	[800-131A].		[NIST.800-131A].
	This memo updates RFC 4252 and RFC 4253 to define new public key		This memo updates RFCs 4252 and 4253 to define new public key
	algorithms allowing for interoperable use of existing and new RSA keys		algorithms allowing for interoperable use of existing and new RSA
	with SHA-256 and SHA-512.		keys with SHA-256 and SHA-512.
	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", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	document are to be interpreted as described in [RFC2119].		"OPTIONAL" in this document are to be interpreted as described in
			BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
			capitals, as shown here.
	1.2. Wire Encoding Terminology		1.2. Wire Encoding Terminology
	The wire encoding types in this document - "boolean", "byte",		The wire encoding types in this document -- "boolean", "byte",
	"string", "mpint" - have meanings as described in [RFC4251].		"string", "mpint" -- have meanings as described in [RFC4251].
	2. Public Key Format vs. Public Key Algorithm		2. Public Key Format vs. Public Key Algorithm
	In [RFC4252], the concept "public key algorithm" is used to establish		In [RFC4252], the concept "public key algorithm" is used to establish
	a relationship between one algorithm name, and:		a relationship between one algorithm name, and:
	A. Procedures used to generate and validate a private/public keypair.		A. procedures used to generate and validate a private/public
	B. A format used to encode a public key.		keypair;
	C. Procedures used to calculate, encode, and verify a signature.		B. a format used to encode a public key; and
			C. procedures used to calculate, encode, and verify a signature.
	This document uses the term "public key format" to identify only A and		This document uses the term "public key format" to identify only A
	B in isolation. The term "public key algorithm" continues to identify		and B in isolation. The term "public key algorithm" continues to
	all three aspects A, B, and C.		identify all three aspects -- A, B, and C.
	3. New RSA Public Key Algorithms		3. New RSA Public Key Algorithms
	This memo adopts the style and conventions of [RFC4253] in specifying		This memo adopts the style and conventions of [RFC4253] in specifying
	how use of a public key algorithm is indicated in SSH.		how use of a public key algorithm is indicated in SSH.
	The following new public key algorithms are defined:		The following new public key algorithms are defined:
	rsa-sha2-256 RECOMMENDED sign Raw RSA key		rsa-sha2-256 RECOMMENDED sign Raw RSA key
	rsa-sha2-512 OPTIONAL sign Raw RSA key		rsa-sha2-512 OPTIONAL sign Raw RSA key
	These algorithms are suitable for use both in the SSH transport layer		These algorithms are suitable for use both in the SSH transport layer
	[RFC4253] for server authentication, and in the authentication layer		[RFC4253] for server authentication and in the authentication layer
	[RFC4252] for client authentication.		[RFC4252] for client authentication.
	Since RSA keys are not dependent on the choice of hash function, the		Since RSA keys are not dependent on the choice of hash function, the
	new public key algorithms reuse the "ssh-rsa" public key format as		new public key algorithms reuse the "ssh-rsa" public key format as
	defined in [RFC4253]:		defined in [RFC4253]:
	string "ssh-rsa"		string "ssh-rsa"
	mpint e		mpint e
	mpint n		mpint n
	All aspects of the "ssh-rsa" format are kept, including the encoded		All aspects of the "ssh-rsa" format are kept, including the encoded
	string "ssh-rsa". This allows existing RSA keys to be used with the		string "ssh-rsa". This allows existing RSA keys to be used with the
	new public key algorithms, without requiring re-encoding, or affecting		new public key algorithms, without requiring re-encoding or affecting
	already trusted key fingerprints.		already trusted key fingerprints.
	Signing and verifying using these algorithms is performed according to		Signing and verifying using these algorithms is performed according
	the RSASSA-PKCS1-v1_5 scheme in [RFC8017] using SHA-2 [SHS] as hash.		to the RSASSA-PKCS1-v1_5 scheme in [RFC8017] using SHA-2 [SHS] as
			hash.
	For the algorithm "rsa-sha2-256", the hash used is SHA-256.		For the algorithm "rsa-sha2-256", the hash used is SHA-256.
	For the algorithm "rsa-sha2-512", the hash used is SHA-512.		For the algorithm "rsa-sha2-512", the hash used is SHA-512.
	The resulting signature is encoded as follows:		The resulting signature is encoded as follows:
	string "rsa-sha2-256" / "rsa-sha2-512"		string "rsa-sha2-256" / "rsa-sha2-512"
	string rsa_signature_blob		string rsa_signature_blob
	The value for 'rsa_signature_blob' is encoded as a string containing		The value for 'rsa_signature_blob' is encoded as a string that
	S - an octet string which is the output of RSASSA-PKCS1-v1_5, of		contains an octet string S (which is the output of RSASSA-PKCS1-v1_5)
	length equal to the length in octets of the RSA modulus.		and that has the same length (in octets) as the RSA modulus. When S
			contains leading zeros, there exist signers that will send a shorter
			encoding of S that omits them. A verifier MAY accept shorter
			encodings of S with one or more leading zeros omitted.
	3.1. Use for server authentication		3.1. Use for Server Authentication
	To express support and preference for one or both of these algorithms		To express support and preference for one or both of these algorithms
	for server authentication, the SSH client or server includes one or		for server authentication, the SSH client or server includes one or
	both algorithm names, "rsa-sha2-256" and/or "rsa-sha2-512", in the		both algorithm names, "rsa-sha2-256" and/or "rsa-sha2-512", in the
	name-list field "server_host_key_algorithms" in the SSH_MSG_KEXINIT		name-list field "server_host_key_algorithms" in the SSH_MSG_KEXINIT
	packet [RFC4253]. If one of the two host key algorithms is negotiated,		packet [RFC4253]. If one of the two host key algorithms is
	the server sends an "ssh-rsa" public key as part of the negotiated key		negotiated, the server sends an "ssh-rsa" public key as part of the
	exchange method (e.g. in SSH_MSG_KEXDH_REPLY), and encodes a signature		negotiated key exchange method (e.g., in SSH_MSG_KEXDH_REPLY) and
	with the appropriate signature algorithm name - either "rsa-sha2-256",		encodes a signature with the appropriate signature algorithm name --
	or "rsa-sha2-512".		either "rsa-sha2-256" or "rsa-sha2-512".
	3.2. Use for client authentication		3.2. Use for Client Authentication
	To use this algorithm for client authentication, the SSH client sends		To use this algorithm for client authentication, the SSH client sends
	an SSH_MSG_USERAUTH_REQUEST message [RFC4252] encoding the "publickey"		an SSH_MSG_USERAUTH_REQUEST message [RFC4252] encoding the
	method, and encoding the string field "public key algorithm name" with		"publickey" method and encoding the string field "public key
	the value "rsa-sha2-256" or "rsa-sha2-512". The "public key blob"		algorithm name" with the value "rsa-sha2-256" or "rsa-sha2-512". The
	field encodes the RSA public key using the "ssh-rsa" public key		"public key blob" field encodes the RSA public key using the
	format.		"ssh-rsa" public key format.
	For example, as defined in [RFC4252] and [RFC4253], an SSH "publickey"		For example, as defined in [RFC4252] and [RFC4253], an SSH
	authentication request using an "rsa-sha2-512" signature would be		"publickey" authentication request using an "rsa-sha2-512" signature
	properly encoded as follows:		would be properly encoded as follows:
	byte SSH_MSG_USERAUTH_REQUEST		byte SSH_MSG_USERAUTH_REQUEST
	string user name		string user name
	string service name		string service name
	string "publickey"		string "publickey"
	boolean TRUE		boolean TRUE
	string "rsa-sha2-512"		string "rsa-sha2-512"
	string public key blob:		string public key blob:
	string "ssh-rsa"		string "ssh-rsa"
	mpint e		mpint e
	mpint n		mpint n
	string signature:		string signature:
	string "rsa-sha2-512"		string "rsa-sha2-512"
	string rsa_signature_blob		string rsa_signature_blob
	If the client includes the signature field, the client MUST encode the		If the client includes the signature field, the client MUST encode
	same algorithm name in the signature as in SSH_MSG_USERAUTH_REQUEST -		the same algorithm name in the signature as in
	either "rsa-sha2-256", or "rsa-sha2-512". If a server receives a		SSH_MSG_USERAUTH_REQUEST -- either "rsa-sha2-256" or "rsa-sha2-512".
	mismatching request, it MAY apply arbitrary authentication penalties,		If a server receives a mismatching request, it MAY apply arbitrary
	including but not limited to authentication failure or disconnect.		authentication penalties, including but not limited to authentication
			failure or disconnect.
	OpenSSH 7.2 (but not 7.2p2) incorrectly encodes the algorithm in the		OpenSSH 7.2 (but not 7.2p2) incorrectly encodes the algorithm in the
	signature as "ssh-rsa" when the algorithm in SSH_MSG_USERAUTH_REQUEST		signature as "ssh-rsa" when the algorithm in SSH_MSG_USERAUTH_REQUEST
	is "rsa-sha2-256" or "rsa-sha2-512". In this case, the signature does		is "rsa-sha2-256" or "rsa-sha2-512". In this case, the signature
	actually use either SHA-256 or SHA-512. A server MAY, but is not		does actually use either SHA-256 or SHA-512. A server MAY, but is
	required to, accept this variant, or another variant that corresponds		not required to, accept this variant or another variant that
	to a good-faith implementation, and is decided to be safe to accept.		corresponds to a good-faith implementation and is considered safe to
			accept.
	3.3. Discovery of public key algorithms supported by servers		3.3. Discovery of Public Key Algorithms Supported by Servers
	Implementation experience has shown that there are servers which apply		Implementation experience has shown that there are servers that apply
	authentication penalties to clients attempting public key algorithms		authentication penalties to clients attempting public key algorithms
	which the SSH server does not support.		that the SSH server does not support.
	Servers that accept rsa-sha2-* signatures for client authentication		Servers that accept rsa-sha2-* signatures for client authentication
	SHOULD implement the extension negotiation mechanism defined in		SHOULD implement the extension negotiation mechanism defined in
	[EXT-INFO], including especially the "server-sig-algs" extension.		[RFC8308], including especially the "server-sig-algs" extension.
	When authenticating with an RSA key against a server that does not		When authenticating with an RSA key against a server that does not
	implement the "server-sig-algs" extension, clients MAY default to an		implement the "server-sig-algs" extension, clients MAY default to an
	"ssh-rsa" signature to avoid authentication penalties. When the new		"ssh-rsa" signature to avoid authentication penalties. When the new
	rsa-sha2-* algorithms have been sufficiently widely adopted to warrant		rsa-sha2-* algorithms have been sufficiently widely adopted to
	disabling "ssh-rsa", clients MAY default to one of the new algorithms.		warrant disabling "ssh-rsa", clients MAY default to one of the new
			algorithms.
	4. IANA Considerations		4. IANA Considerations
	IANA is requested to update the "Secure Shell (SSH) Protocol		IANA has updated the "Secure Shell (SSH) Protocol Parameters"
	Parameters" registry established with [RFC4250], to extend the table		registry, established with [RFC4250], to extend the table "Public Key
	Public Key Algorithm Names [IANA-PKA]:		Algorithm Names" [IANA-PKA] as follows.
	- To the immediate right of the column Public Key Algorithm Name,		- To the immediate right of the column "Public Key Algorithm Name",
	a new column is to be added, titled Public Key Format. For existing		a new column has been added, titled "Public Key Format". For
	entries, the column Public Key Format should be assigned the same		existing entries, the column "Public Key Format" has been assigned
	value found under Public Key Algorithm Name.		the same value as under "Public Key Algorithm Name".
	- Immediately following the existing entry for "ssh-rsa", two sibling		- Immediately following the existing entry for "ssh-rsa", two
	entries are to be added:		sibling entries have been added:
	P. K. Alg. Name P. K. Format Reference Note		P. K. Alg. Name P. K. Format Reference Note
	rsa-sha2-256 ssh-rsa [this document] Section 3		rsa-sha2-256 ssh-rsa RFC 8332 Section 3
	rsa-sha2-512 ssh-rsa [this document] Section 3		rsa-sha2-512 ssh-rsa RFC 8332 Section 3
	5. Security Considerations		5. Security Considerations
	The security considerations of [RFC4251] apply to this document.		The security considerations of [RFC4251] apply to this document.
	5.1. Key Size and Signature Hash		5.1. Key Size and Signature Hash
	The National Institute of Standards and Technology (NIST) Special		The National Institute of Standards and Technology (NIST) Special
	Publication 800-131A, Revision 1 [800-131A], disallows the use of RSA		Publication 800-131A, Revision 1 [NIST.800-131A] disallows RSA and
	and DSA keys shorter than 2048 bits for US government use. The same		DSA keys shorter than 2048 bits for US government use. The same
	document disallows the SHA-1 hash function for digital signature		document disallows the SHA-1 hash function for digital signature
	generation, except under NIST's protocol-specific guidance.		generation, except under NIST's protocol-specific guidance.
	It is prudent to follow this advice also outside of US government use.		It is prudent to follow this advice also outside of US government
			use.
	5.2. Transition		5.2. Transition
	This document is based on the premise that RSA is used in environments		This document is based on the premise that RSA is used in
	where a gradual, compatible transition to improved algorithms will be		environments where a gradual, compatible transition to improved
	better received than one that is abrupt and incompatible. It advises		algorithms will be better received than one that is abrupt and
	that SSH implementations add support for new RSA public key algorithms		incompatible. It advises that SSH implementations add support for
	along with SSH_MSG_EXT_INFO and the "server-sig-algs" extension to		new RSA public key algorithms along with SSH_MSG_EXT_INFO and the
	allow coexistence of new deployments with older versions that support		"server-sig-algs" extension to allow coexistence of new deployments
	only "ssh-rsa". Nevertheless, implementations SHOULD start to disable		with older versions that support only "ssh-rsa". Nevertheless,
	"ssh-rsa" in their default configurations as soon as they have reason		implementations SHOULD start to disable "ssh-rsa" in their default
	to believe that new RSA signature algorithms have been widely adopted.		configurations as soon as the implementers believe that new RSA
			signature algorithms have been widely adopted.
	5.3. PKCS#1 v1.5 Padding and Signature Verification		5.3. PKCS #1 v1.5 Padding and Signature Verification
	This document prescribes RSASSA-PKCS1-v1_5 signature padding because:		This document prescribes RSASSA-PKCS1-v1_5 signature padding because:
	(1) RSASSA-PSS is not universally available to all implementations;		(1) RSASSA-PSS is not universally available to all implementations;
	(2) PKCS#1 v1.5 is widely supported in existing SSH implementations;		(2) PKCS #1 v1.5 is widely supported in existing SSH
	(3) PKCS#1 v1.5 is not known to be insecure for use in this scheme.		implementations;
			(3) PKCS #1 v1.5 is not known to be insecure for use in this scheme.
	Implementers are advised that a signature with PKCS#1 v1.5 padding		Implementers are advised that a signature with RSASSA-PKCS1-v1_5
	MUST NOT be verified by applying the RSA key to the signature, and		padding MUST NOT be verified by applying the RSA key to the
	then parsing the output to extract the hash. This may give an attacker		signature, and then parsing the output to extract the hash. This may
	opportunities to exploit flaws in the parsing and vary the encoding.		give an attacker opportunities to exploit flaws in the parsing and
	Verifiers MUST instead apply PKCS#1 v1.5 padding to the expected hash,		vary the encoding. Verifiers MUST instead apply RSASSA-PKCS1-v1_5
	then compare the encoded bytes with the output of the RSA operation.		padding to the expected hash, then compare the encoded bytes with the
			output of the RSA operation.
	6. References		6. References
	6.1. Normative References		6.1. Normative References
	[SHS] National Institute of Standards and Technology (NIST),		[SHS] NIST, "Secure Hash Standard (SHS)", FIPS Publication
	United States of America, "Secure Hash Standard (SHS)",		180-4, August 2015,
	FIPS Publication 180-4, August 2015,
	<http://dx.doi.org/10.6028/NIST.FIPS.180-4>.		<http://dx.doi.org/10.6028/NIST.FIPS.180-4>.
	[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, March 1997.		Requirement Levels", BCP 14, RFC 2119,
			DOI 10.17487/RFC2119, March 1997,
			<https://www.rfc-editor.org/info/rfc2119>.
	[RFC4251] Lehtinen, S. and C. Lonvick, Ed., "The Secure Shell (SSH)		[RFC4251] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
	Protocol Architecture", RFC 4251, January 2006.		Protocol Architecture", RFC 4251, DOI 10.17487/RFC4251,
			January 2006, <https://www.rfc-editor.org/info/rfc4251>.
	[RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)		[RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
	Authentication Protocol", RFC 4252, January 2006.		Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252,
			January 2006, <https://www.rfc-editor.org/info/rfc4252>.
	[RFC4253] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)		[RFC4253] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
	Transport Layer Protocol", RFC 4253, January 2006.		Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253,
			January 2006, <https://www.rfc-editor.org/info/rfc4253>.
	[EXT-INFO] Bider, D., "Extension Negotiation in Secure Shell (SSH)",		[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
	draft-ietf-curdle-ssh-ext-info-15.txt, September 2017,		2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
	<https://tools.ietf.org/html/		May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	draft-ietf-curdle-ssh-ext-info-15>.
			[RFC8308] Bider, D., "Extension Negotiation in the Secure Shell
			(SSH) Protocol", RFC 8308, DOI 10.17487/RFC8308, March
			2018, <https://www.rfc-editor.org/info/rfc8308>.
	6.2. Informative References		6.2. Informative References
	[800-131A] National Institute of Standards and Technology (NIST),		[NIST.800-131A]
	"Transitions: Recommendation for Transitioning the Use of		NIST, "Transitions: Recommendation for Transitioning the
	Cryptographic Algorithms and Key Lengths", NIST Special		Use of Cryptographic Algorithms and Key Lengths", NIST
	Publication 800-131A, Revision 1, November 2015,		Special Publication 800-131A, Revision 1,
			DOI 10.6028/NIST.SP.800-131Ar1, November 2015,
	<http://nvlpubs.nist.gov/nistpubs/SpecialPublications/		<http://nvlpubs.nist.gov/nistpubs/SpecialPublications/
	NIST.SP.800-131Ar1.pdf>.		NIST.SP.800-131Ar1.pdf>.
	[RFC4250] Lehtinen, S. and C. Lonvick, Ed., "The Secure Shell (SSH)		[RFC4250] Lehtinen, S. and C. Lonvick, Ed., "The Secure Shell (SSH)
	Protocol Assigned Numbers", RFC 4250, January 2006.		Protocol Assigned Numbers", RFC 4250,
			DOI 10.17487/RFC4250, January 2006,
			<https://www.rfc-editor.org/info/rfc4250>.
	[RFC8017] Moriarty, K., Kaliski, B., Jonsson, J. and Rusch, A.,		[RFC8017] Moriarty, K., Ed., Kaliski, B., Jonsson, J., and A. Rusch,
	"PKCS #1: RSA Cryptography Specifications Version 2.2",		"PKCS #1: RSA Cryptography Specifications Version 2.2",
	RFC 8017, November 2016.		RFC 8017, DOI 10.17487/RFC8017, November 2016,
			<https://www.rfc-editor.org/info/rfc8017>.
	[IANA-PKA] "Secure Shell (SSH) Protocol Parameters",		[IANA-PKA]
	<https://www.iana.org/assignments/ssh-parameters/		IANA, "Secure Shell (SSH) Protocol Parameters",
	ssh-parameters.xhtml#ssh-parameters-19>.		<https://www.iana.org/assignments/ssh-parameters/>.
	Author's Address		Acknowledgments
	Denis Bider		Thanks to Jon Bright, Niels Moeller, Stephen Farrell, Mark D.
	Bitvise Limited		Baushke, Jeffrey Hutzelman, Hanno Boeck, Peter Gutmann, Damien
	4105 Lombardy Court		Miller, Mat Berchtold, Roumen Petrov, Daniel Migault, Eric Rescorla,
	Colleyville, Texas 76034		Russ Housley, Alissa Cooper, Adam Roach, and Ben Campbell for
	United States of America		reviews, comments, and suggestions.
	Email: ietf-ssh3@denisbider.com		Author's Address
	URI: https://www.bitvise.com/
	Acknowledgments		Denis Bider
			Bitvise Limited
			4105 Lombardy Court
			Colleyville, Texas 76034
			United States of America
	Thanks to Jon Bright, Niels Moeller, Stephen Farrell, Mark D. Baushke,		Email: ietf-ssh3@denisbider.com
	Jeffrey Hutzelman, Hanno Boeck, Peter Gutmann, Damien Miller, Mat		URI: https://www.bitvise.com/
	Berchtold, Roumen Petrov, Daniel Migault, Eric Rescorla, Russ Housley,
	Alissa Cooper, Adam Roach, and Ben Campbell for reviews, comments, and
	suggestions.
End of changes. 72 change blocks.
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