Independent Submission L. Corcoran
Request for Comments: 9206 M. Jenkins
Category: Informational NSA
ISSN: 2070-1721 February 2022
Commercial National Security Algorithm (CNSA) Suite Cryptography for
Internet Protocol Security (IPsec)
Abstract
The United States Government has published the National Security
Agency's Commercial National Security Algorithm (CNSA) Suite, which
defines cryptographic algorithm policy for national security
applications. This document specifies the conventions for using the
United States National Security Agency's CNSA Suite algorithms in
Internet Protocol Security (IPsec). It applies to the capabilities,
configuration, and operation of all components of US National
Security Systems (described in NIST Special Publication 800-59) that
employ IPsec. This document is also appropriate for all other US
Government systems that process high-value information. It is made
publicly available for use by developers and operators of these and
any other system deployments.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This is a contribution to the RFC Series, independently of any other
RFC stream. The RFC Editor has chosen to publish this document at
its discretion and makes no statement about its value for
implementation or deployment. Documents approved for publication by
the RFC Editor are not candidates for any level of Internet Standard;
see Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9206.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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to this document.
Table of Contents
1. Introduction
2. Terminology
3. The Commercial National Security Algorithm Suite
4. CNSA-Compliant IPsec Overview
5. IPsec User Interface Suites
5.1. Suite CNSA-GCM-256-ECDH-384
5.2. Suite CNSA-GCM-256-DH-3072
5.3. Suite CNSA-GCM-256-DH-4096
6. IKEv2 Authentication
7. Certificates
8. IKEv2 Security Associations (SAs)
9. The Key Exchange Payload in the IKE_SA_INIT Exchange
10. Generating Key Material for the IKE SA
11. Additional Requirements
12. Guidance for Applications with Long Data-Protection
Requirements
13. Security Considerations
14. IANA Considerations
15. References
15.1. Normative References
15.2. Informative References
Authors' Addresses
1. Introduction
This document specifies the conventions for using the United States
National Security Agency's (NSA's) Commercial National Security
Algorithm (CNSA) Suite algorithms [CNSA] in Internet Protocol
Security (IPsec). It defines CNSA-based User Interface suites ("UI
suites") describing sets of security configurations for Internet Key
Exchange Protocol Version 2 (IKEv2) and IP Encapsulating Security
Payload (ESP) protocol use, and specifies certain other constraints
with respect to algorithm selection and configuration. It applies to
the capabilities, configuration, and operation of all components of
US National Security Systems (described in NIST Special Publication
800-59 [SP80059]) that employ IPsec. This document is also
appropriate for all other US Government systems that process high-
value information. It is made publicly available for use by
developers and operators of these and any other system deployments.
The reader is assumed to have familiarity with the following:
* "IP Encapsulating Security Payload (ESP)" [RFC4303]
* "Internet X.509 Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile" [RFC5280]
* "Internet Key Exchange Protocol Version 2 (IKEv2)" [RFC7296]
* "Cryptographic Algorithm Implementation Requirements and Usage
Guidance for Encapsulating Security Payload (ESP) and
Authentication Header (AH)" [RFC8221]
* "Commercial National Security Algorithm (CNSA) Suite Certificate
and Certificate Revocation List (CRL) Profile" [RFC8603]
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"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.
AES refers to the Advanced Encryption Standard. ECDSA and ECDH refer
to the use of the Elliptic Curve Digital Signature Algorithm (ECDSA)
and Elliptic Curve Diffie-Hellman (ECDH), respectively. DH refers to
Diffie-Hellman key establishment. RSA refers to an RSA signature.
3. The Commercial National Security Algorithm Suite
The NSA profiles commercial cryptographic algorithms and protocols as
part of its mission to support secure, interoperable communications
for US Government National Security Systems. To this end, it
publishes guidance to both (1) assist with the US Government
transition to new algorithms and (2) provide vendors -- and the
Internet community in general -- with information concerning their
proper use and configuration.
Recently, cryptographic transition plans have become overshadowed by
the prospect of the development of a cryptographically relevant
quantum computer. The NSA has established the Commercial National
Security Algorithm (CNSA) Suite to provide vendors and IT users near-
term flexibility in meeting their information assurance
interoperability requirements. The purpose behind this flexibility
is to avoid vendors and customers making two major transitions in a
relatively short timeframe, as we anticipate a need to shift to
quantum-resistant cryptography in the near future.
The NSA is authoring a set of RFCs, including this one, to provide
updated guidance concerning the use of certain commonly available
commercial algorithms in IETF protocols. These RFCs can be used in
conjunction with other RFCs and cryptographic guidance (e.g., NIST
Special Publications) to properly protect Internet traffic and data-
at-rest for US Government National Security Systems.
4. CNSA-Compliant IPsec Overview
CNSA-compliant implementations for IPsec MUST use IKEv2 [RFC7296].
Implementing a CNSA-compliant IPsec system requires cryptographic
algorithm selection for both the IKEv2 and ESP protocols. The
following CNSA requirements apply to IPsec:
Encryption:
AES [FIPS197] (with key size 256 bits)
Digital Signature:
ECDSA [FIPS186] (using the NIST P-384 elliptic curve)
RSA [FIPS186] (with a modulus of 3072 bits or larger)
Key Establishment:
ECDH [SP80056A] (using the NIST P-384 elliptic curve)
DH [RFC3526] (with a prime modulus of 3072 or larger)
To facilitate selection of appropriate combinations of compliant
algorithms, this document provides CNSA-compliant User Interface
suites (UI suites) [RFC4308] to implement IPsec on National Security
Systems.
The approved CNSA hash function for all purposes is SHA-384, as
defined in [FIPS180]. However, PRF_HMAC_SHA_512 is specified for the
IKEv2 Pseudorandom Function (PRF) instead of PRF_HMAC_SHA_384, due to
availability. See Section 8 below.
For CNSA Suite applications, public key certificates MUST be
compliant with the CNSA Suite Certificate and CRL Profile specified
in [RFC8603].
Under certain conditions, such as applications having long-lived
data-protection requirements, systems that do not comply with the
requirements of this document are acceptable; see Section 12.
5. IPsec User Interface Suites
User Interface (UI) suites [RFC4308] are named suites that cover some
typical security policy options for IPsec. Use of UI suites does not
change the IPsec protocol in any way. The following UI suites
provide cryptographic algorithm choices for ESP [RFC4303] and for
IKEv2 [RFC7296]. The selection of a UI suite will depend on the key
exchange algorithm. The suite names indicate the Advanced Encryption
Standard [FIPS197] mode, AES key length specified for encryption, and
the key exchange algorithm.
Although RSA is also a CNSA-approved key establishment algorithm,
only DH or and ECDH are specified for key exchange in IKEv2 [RFC7296].
RSA in IPsec is used only for digital signatures. See Section 6.
ESP requires negotiation of both a confidentiality algorithm and an
integrity algorithm. However, algorithms for Authenticated
Encryption with Associated Data (AEAD) [RFC5116] do not require a
separate integrity algorithm to be negotiated. In particular, since
AES-GCM is an AEAD algorithm, ESP implementing AES-GCM MUST either
offer no integrity algorithm or indicate the single integrity
algorithm NONE (see Section 3.3 of [RFC7296]).
To be CNSA compliant, IPsec implementations that use the following UI
suites MUST use the suite names listed below. IPsec implementations
SHOULD NOT use names different than those listed here for the suites
that are described and MUST NOT use the names listed here for suites
that do not match these values. These requirements are necessary for
interoperability.
Transform names are as listed in the IANA "Internet Key Exchange
Version 2 (IKEv2) Parameters" registry. Definitions of the
transforms are contained in the references specified in that
registry.
Other UI suites may be acceptable for CNSA compliance. See Section 8
for details.
5.1. Suite CNSA-GCM-256-ECDH-384
ESP SA:
Encryption: ENCR_AES_GCM_16 (with key size 256 bits)
Integrity: NONE
IKEv2 SA:
Encryption: ENCR_AES_GCM_16 (with key size 256 bits)
PRF: PRF_HMAC_SHA2_512
Integrity: NONE
Diffie-Hellman group: 384-bit random ECP group
5.2. Suite CNSA-GCM-256-DH-3072
ESP SA:
Encryption: ENCR_AES_GCM_16 (with key size 256 bits)
Integrity: NONE
IKEv2 SA:
Encryption: ENCR_AES_GCM_16 (with key size 256 bits)
PRF: PRF_HMAC_SHA2_512
Integrity: NONE
Diffie-Hellman group: 3072-bit MODP group
5.3. Suite CNSA-GCM-256-DH-4096
ESP SA:
Encryption: ENCR_AES_GCM_16 (with key size 256 bits)
Integrity: NONE
IKEv2 SA:
Encryption: ENCR_AES_GCM_16 (with key size 256 bits)
PRF: PRF_HMAC_SHA2_512
Integrity: NONE
Diffie-Hellman group: 4096-bit MODP group
6. IKEv2 Authentication
Authentication of the IKEv2 Security Association (SA) requires
computation of a digital signature. To be CNSA compliant, digital
signatures MUST be generated with SHA-384 as defined in [RFC8017]
together with either ECDSA-384 as defined in [RFC4754] or RSA with
3072-bit or greater modulus. (For applications with long data-
protection requirements, somewhat different rules apply; see
Section 12.)
Initiators and responders MUST be able to verify ECDSA-384 signatures
and MUST be able to verify RSA with 3072-bit or 4096-bit modulus and
SHA-384 signatures.
For CNSA-compliant systems, authentication methods other than
ECDSA-384 or RSA MUST NOT be accepted for IKEv2 authentication. A
3072-bit modulus or larger MUST be used for RSA. If the relying
party receives a message signed with any authentication method other
than an ECDSA-384 or RSA signature, it MUST return an
AUTHENTICATION_FAILED notification and stop processing the message.
If the relying party receives a message signed with RSA using less
than a 3072-bit modulus, it MUST return an AUTHENTICATION_FAILED
notification and stop processing the message.
7. Certificates
To be CNSA compliant, the initiator and responder MUST use X.509
certificates that comply with [RFC8603]. Peer authentication
decisions must be based on the Subject or Subject Alternative Name
from the certificate that contains the key used to validate the
signature in the Authentication Payload as defined in Section 3.8 of
[RFC7296], rather than the Identification Data from the
Identification Payload that is used to look up policy.
8. IKEv2 Security Associations (SAs)
Section 5 specifies three UI suites for ESP and IKEv2 Security
Associations. All three use AES-GCM for encryption but differ in the
key exchange algorithm. Galois/Counter Mode (GCM) [RFC4106] combines
counter (CTR) mode with a secure, parallelizable, and efficient
authentication mechanism. Since AES-GCM is an AEAD algorithm, ESP
implements AES-GCM with no additional integrity algorithm (see
Section 3.3 of [RFC7296]).
An initiator proposal SHOULD be constructed from one or more of the
following suites:
* CNSA-GCM-256-ECDH-384
* CNSA-GCM-256-DH-3072
* CNSA-GCM-256-DH-4096
A responder SHOULD accept proposals constructed from at least one of
the three named suites. Other UI suites may result in acceptable
proposals (such as those based on PRF_HMAC_SHA2_384); however, these
are provided to promote interoperability.
Nonce construction for AES-GCM using a misuse-resistant technique
[RFC8452] conforms with the requirements of this document and MAY be
used if a Federal Information Processing Standard (FIPS) validated
implementation is available.
The named UI suites specify PRF_HMAC_SHA2_512 for the IKEv2 SA PRF
transform, as PRF_HMAC_SHA2_384 is not listed among required PRF
transforms in [RFC8247]; therefore, implementation of the latter is
likely to be scarce. The security level of PRF_HMAC_SHA2_512 is
comparable, and the difference in performance is negligible.
However, SHA-384 is the official CNSA algorithm for computing a
condensed representation of information. Therefore, the
PRF_HMAC_SHA2_384 transform is CNSA compliant if it is available to
the initiator and responder. Any PRF transform other than
PRF_HMAC_SHA2_384 or PRF_HMAC_SHA2_512 MUST NOT be used.
If none of the proposals offered by the initiator consist solely of
transforms based on CNSA algorithms (such as those in the UI suites
defined in Section 5), the responder MUST return a Notify payload
with the error NO_PROPOSAL_CHOSEN when operating in CNSA-compliant
mode.
9. The Key Exchange Payload in the IKE_SA_INIT Exchange
The key exchange payload is used to exchange Diffie-Hellman public
numbers as part of a Diffie-Hellman key exchange. The CNSA-compliant
initiator and responder MUST each generate an ephemeral key pair to
be used in the key exchange.
If the Elliptic Curve Diffie-Hellman (ECDH) key exchange is selected
for the SA, the initiator and responder both MUST generate an
elliptic curve (EC) key pair using the P-384 elliptic curve. The
ephemeral public keys MUST be stored in the key exchange payload as
described in [RFC5903].
If the Diffie-Hellman (DH) key exchange is selected for the SA, the
initiator and responder both MUST generate a key pair using the
appropriately sized MODP group as described in [RFC3526]. The size
of the MODP group will be determined by the selection of either a
3072-bit or greater modulus for the SA.
10. Generating Key Material for the IKE SA
As noted in Section 7 of [RFC5903], the shared secret result of an
ECDH key exchange is the 384-bit x value of the ECDH common value.
The shared secret result of a DH key exchange is the number of octets
needed to accommodate the prime (e.g., 384 octets for 3072-bit MODP
group) with leading zeros as necessary, as described in Section 2.1.2
of [RFC2631].
IKEv2 allows for the reuse of Diffie-Hellman private keys; see
Section 2.12 of [RFC7296]. However, there are security concerns
related to this practice. Section 5.6.3.3 of [SP80056A] states that
an ephemeral private key MUST be used in exactly one key
establishment transaction and MUST be destroyed (zeroized) as soon as
possible. Section 5.8 of [SP80056A] states that any shared secret
derived from key establishment MUST be destroyed (zeroized)
immediately after its use. CNSA-compliant IPsec systems MUST follow
the mandates in [SP80056A].
11. Additional Requirements
The IPsec protocol AH MUST NOT be used in CNSA-compliant
implementations.
A Diffie-Hellman group MAY be negotiated for a Child SA as described
in Section 1.3 of [RFC7296], allowing peers to employ Diffie-Hellman
in the CREATE_CHILD_SA exchange. If a transform of type 4 is
specified for an SA for ESP, the value of that transform MUST match
the value of the transform used by the IKEv2 SA.
Per [RFC7296], if a CREATE_CHILD_SA exchange includes a KEi payload,
at least one of the SA offers MUST include the Diffie-Hellman group
of the KEi. For CNSA-compliant IPsec implementations, the Diffie-
Hellman group of the KEi MUST use the same group used in the
IKE_INIT_SA.
For IKEv2, rekeying of the CREATE_CHILD_SA MUST be supported by both
parties. The initiator of this exchange MAY include a new Diffie-
Hellman key; if it is included, it MUST use the same group used in
the IKE_INIT_SA. If the initiator of the exchange includes a Diffie-
Hellman key, the responder MUST include a Diffie-Hellman key, and it
MUST use the same group.
For CNSA-compliant systems, the IKEv2 authentication method MUST use
an end-entity certificate provided by the authenticating party.
Identification Payloads (IDi and IDr) in the IKE_AUTH exchanges MUST
NOT be used for the IKEv2 authentication method but may be used for
policy lookup.
The administrative User Interface (UI) for a system that conforms to
this profile MUST allow the operator to specify a single suite. If
only one suite is specified in the administrative UI, the IKEv2
implementation MUST only offer algorithms for that one suite.
The administrative UI MAY allow the operator to specify more than one
suite; if it allows this, it MUST allow the operator to specify a
preferred order for the suites that are to be offered or accepted.
If more than one suite is specified in the administrative UI, the
IKEv2 implementation MUST only offer algorithms of those suites.
(Note that although this document does not define a UI suite
specifying PRF_HMAC_SHA2_384, a proposal containing such a transform
is CNSA compliant.)
12. Guidance for Applications with Long Data-Protection Requirements
The CNSA mandate is to continue to use current algorithms with
increased security parameters, then transition to approved post-
quantum resilient algorithms when they are identified. However, some
applications have data-in-transit-protection requirements that are
long enough that post-quantum resilient protection must be provided
now. Lacking approved asymmetric post-quantum resilient
confidentiality algorithms, that means approved symmetric techniques
must be used as described in this section until approved post-quantum
resilient asymmetric algorithms are identified.
For new applications, confidentiality and integrity requirements from
the sections above MUST be followed, with the addition of a Pre-
Shared Key (PSK) mixed in as defined in [RFC8784].
Installations currently using IKEv1 with PSKs MUST (1) use AES in
cipher block chaining mode (AES-CBC) in conjunction with a CNSA-
compliant integrity algorithm (e.g., AUTH_HMAC_SHA2_384_192) and (2)
transition to IKEv2 with PSKs [RFC8784] as soon as implementations
become available.
Specific guidance for systems not compliant with the requirements of
this document, including non-GCM modes and PSK length, and PSK
randomness, will be defined in solution-specific requirements
appropriate to the application. Details of those requirements will
depend on the program under which the commercial National Security
Systems solution is developed (e.g., an NSA Commercial Solutions for
Classified Capability Package).
13. Security Considerations
This document inherits all of the security considerations of the
IPsec and IKEv2 documents, including [RFC7296], [RFC4303], [RFC4754],
and [RFC8221].
The security of a system that uses cryptography depends on both the
strength of the cryptographic algorithms chosen and the strength of
the keys used with those algorithms. The security also depends on
the engineering and administration of the protocol used by the system
to ensure that there are no non-cryptographic ways to bypass the
security of the overall system.
When selecting a mode for the AES encryption [RFC5116], be aware that
nonce reuse can result in a loss of confidentiality. Nonce reuse is
catastrophic for GCM, since it also results in a loss of integrity.
14. IANA Considerations
IANA has added the UI suites defined in this document to the
"Cryptographic Suites for IKEv1, IKEv2, and IPsec" registry located
at <https://www.iana.org/assignments/crypto-suites>:
+=======================+===========+
| Identifier | Reference |
+=======================+===========+
| CNSA-GCM-256-ECDH-384 | RFC 9206 |
+-----------------------+-----------+
| CNSA-GCM-256-DH-3072 | RFC 9206 |
+-----------------------+-----------+
| CNSA-GCM-256-DH-4096 | RFC 9206 |
+-----------------------+-----------+
Table 1
15. References
15.1. Normative References
[CNSA] Committee for National Security Systems, "Use of Public
Standards for Secure Information Sharing", CNSSP 15,
October 2016,
<https://www.cnss.gov/CNSS/Issuances/Policies.htm>.
[FIPS180] National Institute of Standards and Technology, "Secure
Hash Standard (SHS)", Federal Information Processing
Standard 180-4, DOI 10.6028/NIST.FIPS.180-4, August 2015,
<https://csrc.nist.gov/publications/detail/fips/180/4/
final>.
[FIPS186] National Institute of Standards and Technology, "Digital
Signature Standard (DSS)", NIST Federal Information
Processing Standard 186-4, DOI 10.6028/NIST.FIPS.186-4,
July 2013,
<https://csrc.nist.gov/publications/detail/fips/186/4/
final>.
[FIPS197] National Institute of Standards and Technology, "Advanced
Encryption Standard (AES)", Federal Information Processing
Standard 197, DOI 10.6028/NIST.FIPS.197, November 2001,
<https://csrc.nist.gov/publications/detail/fips/197/
final>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2631] Rescorla, E., "Diffie-Hellman Key Agreement Method",
RFC 2631, DOI 10.17487/RFC2631, June 1999,
<https://www.rfc-editor.org/info/rfc2631>.
[RFC3526] Kivinen, T. and M. Kojo, "More Modular Exponential (MODP)
Diffie-Hellman groups for Internet Key Exchange (IKE)",
RFC 3526, DOI 10.17487/RFC3526, May 2003,
<https://www.rfc-editor.org/info/rfc3526>.
[RFC4106] Viega, J. and D. McGrew, "The Use of Galois/Counter Mode
(GCM) in IPsec Encapsulating Security Payload (ESP)",
RFC 4106, DOI 10.17487/RFC4106, June 2005,
<https://www.rfc-editor.org/info/rfc4106>.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)",
RFC 4303, DOI 10.17487/RFC4303, December 2005,
<https://www.rfc-editor.org/info/rfc4303>.
[RFC4308] Hoffman, P., "Cryptographic Suites for IPsec", RFC 4308,
DOI 10.17487/RFC4308, December 2005,
<https://www.rfc-editor.org/info/rfc4308>.
[RFC4754] Fu, D. and J. Solinas, "IKE and IKEv2 Authentication Using
the Elliptic Curve Digital Signature Algorithm (ECDSA)",
RFC 4754, DOI 10.17487/RFC4754, January 2007,
<https://www.rfc-editor.org/info/rfc4754>.
[RFC5116] McGrew, D., "An Interface and Algorithms for Authenticated
Encryption", RFC 5116, DOI 10.17487/RFC5116, January 2008,
<https://www.rfc-editor.org/info/rfc5116>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>.
[RFC5903] Fu, D. and J. Solinas, "Elliptic Curve Groups modulo a
Prime (ECP Groups) for IKE and IKEv2", RFC 5903,
DOI 10.17487/RFC5903, June 2010,
<https://www.rfc-editor.org/info/rfc5903>.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <https://www.rfc-editor.org/info/rfc7296>.
[RFC8017] Moriarty, K., Ed., Kaliski, B., Jonsson, J., and A. Rusch,
"PKCS #1: RSA Cryptography Specifications Version 2.2",
RFC 8017, DOI 10.17487/RFC8017, November 2016,
<https://www.rfc-editor.org/info/rfc8017>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8221] Wouters, P., Migault, D., Mattsson, J., Nir, Y., and T.
Kivinen, "Cryptographic Algorithm Implementation
Requirements and Usage Guidance for Encapsulating Security
Payload (ESP) and Authentication Header (AH)", RFC 8221,
DOI 10.17487/RFC8221, October 2017,
<https://www.rfc-editor.org/info/rfc8221>.
[RFC8247] Nir, Y., Kivinen, T., Wouters, P., and D. Migault,
"Algorithm Implementation Requirements and Usage Guidance
for the Internet Key Exchange Protocol Version 2 (IKEv2)",
RFC 8247, DOI 10.17487/RFC8247, September 2017,
<https://www.rfc-editor.org/info/rfc8247>.
[RFC8603] Jenkins, M. and L. Zieglar, "Commercial National Security
Algorithm (CNSA) Suite Certificate and Certificate
Revocation List (CRL) Profile", RFC 8603,
DOI 10.17487/RFC8603, May 2019,
<https://www.rfc-editor.org/info/rfc8603>.
[RFC8784] Fluhrer, S., Kampanakis, P., McGrew, D., and V. Smyslov,
"Mixing Preshared Keys in the Internet Key Exchange
Protocol Version 2 (IKEv2) for Post-quantum Security",
RFC 8784, DOI 10.17487/RFC8784, June 2020,
<https://www.rfc-editor.org/info/rfc8784>.
[SP80056A] National Institute of Standards and Technology,
"Recommendation for Pair-Wise Key Establishment Schemes
Using Discrete Logarithm Cryptography", NIST Special
Publication 800-56A, Revision 3,
DOI 10.6028/NIST.SP.800-56Ar3, April 2018,
<https://csrc.nist.gov/publications/detail/sp/800-56a/rev-
3/final>.
15.2. Informative References
[RFC8452] Gueron, S., Langley, A., and Y. Lindell, "AES-GCM-SIV:
Nonce Misuse-Resistant Authenticated Encryption",
RFC 8452, DOI 10.17487/RFC8452, April 2019,
<https://www.rfc-editor.org/info/rfc8452>.
[SP80059] National Institute of Standards and Technology, "Guideline
for Identifying an Information System as a National
Security System", Special Publication 800-59,
DOI 10.6028/NIST.SP.800-59, August 2003,
<https://csrc.nist.gov/publications/detail/sp/800-59/
final>.
Authors' Addresses
Laura Corcoran
National Security Agency
Email: lscorco@nsa.gov
Michael Jenkins
National Security Agency - Center for Cybersecurity Standards
Email: mjjenki@cyber.nsa.gov