Internet DRAFT - draft-cooley-cnsa-dtls-tls-profile

draft-cooley-cnsa-dtls-tls-profile







Network Working Group                                          D. Cooley
Internet-Draft                                                       NSA
Intended status: Informational                           August 14, 2019
Expires: February 15, 2020


Commercial National Security Algorithm (CNSA) Suite Profile for TLS and
                            DTLS 1.2 and 1.3
                 draft-cooley-cnsa-dtls-tls-profile-00

Abstract

   This document defines a base profile for TLS protocol versions 1.2
   and 1.3, as well as DTLS protocol versions 1.2 and 1.3 for use with
   the United States Commercial National Security Algorithm (CNSA)
   Suite.

   The profile applies to the capabilities, configuration, and operation
   of all components of US National Security Systems that use TLS or
   DTLS.  It is also appropriate for all other US Government systems
   that process high-value information.

   The profile is made publicly available here for use by developers and
   operators of these and any other system deployments.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 15, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.





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   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
   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  The Commercial National Security Algorithm Suite  . . . . . .   3
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  CNSA Suite  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  CNSA (D)TLS Key Establishment Algorithms  . . . . . . . .   5
     4.2.  CNSA TLS Authentication . . . . . . . . . . . . . . . . .   5
   5.  CNSA Compliance and Interoperability Requirements . . . . . .   6
     5.1.  Acceptable ECC Curves . . . . . . . . . . . . . . . . . .   6
     5.2.  Acceptable RSA Schemes, Parameters and Checks . . . . . .   6
     5.3.  Acceptable Finite Field Groups  . . . . . . . . . . . . .   6
     5.4.  Certificates  . . . . . . . . . . . . . . . . . . . . . .   7
   6.  (D)TLS 1.2 Requirements . . . . . . . . . . . . . . . . . . .   7
     6.1.  The signature_algorithms Extension  . . . . . . . . . . .   7
     6.2.  The CertificateRequest Message  . . . . . . . . . . . . .   8
     6.3.  The CertificateVerify Message . . . . . . . . . . . . . .   8
     6.4.  The Signature in the ServerKeyExchange Message  . . . . .   8
     6.5.  Certificate Status  . . . . . . . . . . . . . . . . . . .   8
   7.  (D)TLS 1.3  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     7.1.  The "signature_algorithms" and
           "signature_algorithms_cert" Extensions  . . . . . . . . .   9
     7.2.  The "early_data" Extension  . . . . . . . . . . . . . . .   9
     7.3.  Resumption  . . . . . . . . . . . . . . . . . . . . . . .   9
     7.4.  Certificate Status  . . . . . . . . . . . . . . . . . . .  10
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  10
     10.2.  Informative References . . . . . . . . . . . . . . . . .  13
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   This document specifies a profile of TLS version 1.2 [RFC5246] and
   TLS version 1.3 [RFC8446], as well as DTLS version 1.2 [RFC6347] and
   DTLS version 1.3 [ID.dtls13] for use by applications that support the
   National Security Agency's (NSA) Commercial National Security



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   Algorithm (CNSA) Suite [CNSA].  The profile applies to the
   capabilities, configuration, and operation of all components of US
   National Security Systems [SP80059].  It 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.

   This document does not define any new cipher suites; instead, it
   defines a CNSA compliant profile of TLS and DTLS, and the cipher
   suites defined in [RFC5288] and [RFC5289].  This profile uses only
   algorithms in the CNSA Suite.

   The reader is assumed to have familiarity with the TLS 1.2 and 1.3 as
   well as the DTLS 1.2 and 1.3 protocol specifications: [RFC5246],
   [RFC6347], [RFC8446], and [ID.dtls13].  All MUST-level requirements
   from the protocol documents apply throughout this profile; they are
   generally not repeated.  This profile contains changes that elevate
   some SHOULD-level options to MUST-level; this profile also contains
   changes that elevate some MAY-level options to SHOULD-level or MUST-
   level.  All options that are not mentioned in this profile remain at
   their original requirement level.

2.  The Commercial National Security Algorithm Suite

   The National Security Agency (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 both to assist with the
   US Government transition to new algorithms, and to 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.  NSA has established the CNSA Suite to provide
   vendors and IT users near-term flexibility in meeting their
   Information Assurance (IA) interoperability requirements.  The
   purpose behind this flexibility is to avoid having vendors and
   customers make two major transitions in a relatively short timeframe,
   as we anticipate a need to shift to quantum-resistant cryptography in
   the near future.

   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.



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3.  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.

   "ECDSA" and "ECDH" refer to the use of the Elliptic Curve Digital
   Signature Algorithm (ECDSA) and Elliptic Curve Diffie Hellman (ECDH),
   respectively.  ECDSA and ECDH are used with the NIST P-384 curve
   (which is based on a 384-bit prime modulus) and the SHA-384 hash
   function.  Similarly, "RSA" and "DH" refer to Rivest-Shamir-Adleman
   (RSA) and Finite Field Diffie-Hellman (DH), respectively.  RSA and DH
   are used with a 3072-bit or 4096-bit modulus.  When RSA is used for
   digital signature, it is used with the SHA-384 hash function.

   Henceforth, this document refers to TLS versions 1.2 and 1.3 and DTLS
   versions 1.2 and 1.3 collectively as (D)TLS.

4.  CNSA Suite

   [CNSA] approves the use of both finite field and elliptic curve
   versions of the DH key agreement algorithm, as well as RSA-based key
   establishment.  [CNSA] also approves certain versions of the RSA and
   elliptic curve digital signature algorithms.  The approved encryption
   techniques include the Advanced Encryption Standard (AES) used with a
   256-bit key in an Authenticated Encryption with Associated Data
   (AEAD) mode.

   In particular, CNSA includes the following:

      Encryption:

         AES [AES] (with key size 256 bits), operating in Galois/Counter
         Mode (GCM) [GCM]

      Digital Signature:

         ECDSA [DSS] (using the NIST P-384 elliptic curve)

         RSA [DSS] (with a modulus of 3072 bits or 4096 bits)

      Key Establishment (includes key agreement and key transport):

         ECDH [PWKE-A] (using the NIST P-384 elliptic curve)

         DH [PWKE-A] (with a prime modulus of 3072 or 4096 bits)



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         RSA [PWKE-B] (with a modulus of 3072 or 4096 bits)

   [CNSA] also approves the use of SHA-384 [SHS] for the hash algorithm
   for mask generation, signature generation, Pseudo Random Function
   (PRF) in TLS 1.2 and HMAC-based key derivation function (HKDF) in TLS
   1.3.

4.1.  CNSA (D)TLS Key Establishment Algorithms

   The following combination of algorithms and key sizes are used in
   CNSA (D)TLS:

      AES with 256-bit key, operating in GCM mode

      ECDH [PWKE-A] using the Ephemeral Unified Model Scheme with
      cofactor set to 1 (see Section 6.1.2.2 in [PWKE-A])

      TLS PRF/HKDF with SHA-384 [SHS]

   Or

      AES with 256-bit key, operating in GCM mode

      RSA key transport using 3072-bit or 4096-bit modulus
      [PWKE-B][RFC8017]

      TLS PRF/HKDF with SHA-384 [SHS]

   Or

      AES with 256-bit key, operating in GCM mode

      DH using dhEphem with domain parameters specified below (see
      Section 6.1.2.1 in [PWKE-A])

      TLS PRF/HKDF with SHA-384 [SHS]

   The specific CNSA compliant cipher suites are listed in Section 5.

4.2.  CNSA TLS Authentication

   For server and/or client authentication, CNSA (D)TLS MUST generate
   and verify either ECDSA signatures or RSA signatures.

   In all cases, the client MUST authenticate the server.  The server
   MAY also authenticate the client, as needed by the specific
   application.




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5.  CNSA Compliance and Interoperability Requirements

   CNSA (D)TLS MUST NOT use TLS versions prior to (D)TLS 1.2 in a CNSA
   compliant system.  CNSA (D)TLS servers and clients MUST implement and
   use either (D)TLS version 1.2 [RFC5246][RFC6347] or (D)TLS version
   1.3 [RFC8446][ID.dtls13].

5.1.  Acceptable ECC Curves

   The elliptic curves used in the CNSA Suite appear in the literature
   under two different names [DSS] [SECG].  For the sake of clarity,
   both names are listed below:

         Curve    NIST name   SECG name
         --------------------------------
         P-384    nistp384    secp384r1

   [RFC8422] defines a variety of elliptic curves.  CNSA (D)TLS
   connections MUST use secp384r1(24) (also called nistp384) and the
   uncompressed(0) form MUST be supported, as required by [RFC8422] and
   [RFC8446].

   Key pairs MUST be generated following Section 5.6.1.2 of [PWKE-A].

5.2.  Acceptable RSA Schemes, Parameters and Checks

   [CNSA] specifies a minimum modulus size of 3072 bits; however, only
   two modulus sizes (3072 bits and 4096 bits) are supported by this
   profile.

   For authentication, RSASSA-PKCS1-v1.5 [RFC8017] MUST be supported,
   and RSASSA-PSS [DSS] SHOULD be supported.

   For key transport, RSAES-PKCS1-v1.5 [RFC8017] MUST be supported.

   RSA exponent e MUST satisfy 2^16<e<2^256 and be odd per [DSS].

   If RSASSA-PSS is supported, then the implementation MUST assert
   rsaEncryption as the public key algorithm, the hash algorithm (used
   for both mask generation and signature generation) MUST be SHA-384,
   the mask generation function 1 (MGF1) from [RFC8017] MUST be used,
   and the salt length MUST be 48 octets.

5.3.  Acceptable Finite Field Groups

   [CNSA] specifies a minimum modulus size of 3072 bits; however, only
   two modulus sizes (3072 bits and 4096 bits) are supported by this
   profile.



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   Ephemeral key pairs MUST be generated following Section 5.6.1.1.1 of
   [PWKE-A] using the approved safe prime groups specified in [RFC7919]
   for DH ephemeral key agreement.  The named groups are:

      ffdhe3072 (ID=257)

      ffdhe4096 (ID=258)

5.4.  Certificates

   Certificates used to establish a CNSA (D)TLS connection MUST be
   signed with ECDSA or RSA and MUST be compliant with the "CNSA
   Certificate and Certificate Revocation List (CRL) Profile" [RFC8603].

6.  (D)TLS 1.2 Requirements

   The CNSA (D)TLS 1.2 client MUST offer at least one of these
   ciphersuites:

      TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 [RFC5289]

      TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 [RFC5289]

      TLS_RSA_WITH_AES_256_GCM_SHA384 [RFC5288]

      TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 [RFC5288]

   The CNSA cipher suites listed above MUST be the first (most
   preferred) cipher suites in the ClientHello message.

   A CNSA (D)TLS client that offers interoperability with servers that
   are not CNSA compliant MAY offer additional cipher suites, but any
   additional cipher suites MUST appear after the CNSA cipher suites in
   the ClientHello message.

   A CNSA (D)TLS server MUST accept one of the CNSA suites above if they
   are offered in the ClientHello message.

6.1.  The signature_algorithms Extension

   A CNSA (D)TLS client MUST include the "signature_algorithms"
   extension.  A CNSA (D)TLS client MUST offer a "signature_algorithms"
   extension with either signature=ecdsa and hash=SHA384 or
   signature=rsa and hash=sha384.

   Following the guidance in [RFC8603], CNSA (D)TLS servers MUST only
   accept ECDSA or RSA for certification path validation.




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   Other offerings MAY be included to indicate the acceptable signature
   algorithms in cipher suites that are offered for interoperability
   with servers not compliant with CNSA and to indicate the signature
   algorithms that are acceptable for certification path validation in
   non-compliant CNSA (D)TLS connections.

6.2.  The CertificateRequest Message

   A CNSA (D)TLS server MUST include ECDSA and SHA-384 and/or RSA and
   SHA-384 in the supported_signature_algorithms field.

6.3.  The CertificateVerify Message

   A CNSA (D)TLS server MUST use ECDSA or RSA in the CertificateVerify
   message.  A CNSA (D)TLS client MUST use ECDSA or RSA.

6.4.  The Signature in the ServerKeyExchange Message

   A CNSA (D)TLS server MUST sign the ServerKeyExchange message using
   ECDSA or RSA.

6.5.  Certificate Status

   The client SHOULD request and the server SHOULD provide OSCP
   responses in the "CertificateEntry".

7.  (D)TLS 1.3

   The CNSA (D)TLS client MUST offer the following CipherSuite in the
   ClientHello:

      TLS_AES_256_GCM_SHA384

   The CNSA (D)TLS client MUST offer at least one of the following
   values in the "signature_algorithms" and "signature_algorithms_cert"
   (optional) extensions:

      ecdsa_secp384r1_sha384

      rsa_pkcs1_sha384

   And, if supported, SHOULD offer:

      rsa_pss_pss_sha384

   The CNSA (D)TLS client MUST include at least one of the following
   values in "supported_groups":




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      ECDHE: secp384r1

      DHE: ffdhe3072

      DHE: ffdhe4096

   The CNSA cipher suite MUST be the first (most preferred) cipher
   suites in the ClientHello message and in the extensions.

   A CNSA (D)TLS client that offers interoperability with servers that
   are not CNSA compliant MAY offer additional cipher suites, but any
   additional cipher suites MUST appear after the CNSA compliant cipher
   suites in the ClientHello message.

   A CNSA (D)TLS server MUST accept one of the CNSA algorithms listed
   above if they are offered in the ClientHello message.

7.1.  The "signature_algorithms" and "signature_algorithms_cert"
      Extensions

   A CNSA (D)TLS client MUST include the "signature_algorithms"
   extension.  A CNSA (D)TLS client MAY include the
   "signature_algorithms_cert" extension.  A CNSA (D)TLS client MUST
   offer ECDSA with SHA-384 and/or RSA with SHA-384 in the
   "signature_algorithms" and "signature_algorithm_cert" extensions.

   Following the guidance in [RFC8603], CNSA (D)TLS servers MUST only
   accept ECDSA or RSA for signature path validation.

   Other offerings MAY be included to indicate the acceptable signature
   algorithms in cipher suites that are offered for interoperability
   with servers not compliant with CNSA and to indicate the signature
   algorithms that are acceptable for certification path validation in
   non-compliant CNSA (D)TLS connections.

7.2.  The "early_data" Extension

   A CNSA (D)TLS client or server MUST NOT include the "early_data"
   extension.  See Section 2.3 [RFC8446] for security concerns.

7.3.  Resumption

   A CNSA (D)TLS server MAY send a CNSA (D)TLS client a NewSessionTicket
   extension to enable resumption.  A CNSA (D)TLS client MUST request
   "psk_dhe_ke" via the psk_key_exchange_modes ClientHello extension to
   resume a session.  A CNSA (D)TLS client MUST offer ECDHE with SHA-
   384, RSA with SHA-384 and/or DHE with SHA-384 in the
   "psk_key_exchange_modes" extension.



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7.4.  Certificate Status

   The client SHOULD request and the server SHOULD provide OCSP
   responses in the "CertificateEntry".

8.  Security Considerations

   Most of the security considerations for this document are described
   in [RFC5246], [RFC8446], [RFC6347], and [ID.dtls13].  In addition,
   the security consideration for ECC related to TLS are described in
   [RFC8422], [RFC5288] and [RFC5289].  Readers should consult those
   documents.

   In order to meet the goal of a consistent security level for the
   entire cipher suite, CNSA (D)TLS implementations MUST only use the
   Elliptic Curves, RSA schemes and Finite Fields defined in
   Section 5.1, Section 5.2, and Section 5.3.  Otherwise, it is possible
   to have a set of symmetric algorithms with much weaker security
   properties than the asymmetric algorithms.

   As noted in TLS version 1.3 [RFC8446], TLS does not provide inherent
   replay protections for early data.  For this reason, this profile
   forbids the use of early data.

9.  IANA Considerations

   This document has no IANA actions.

10.  References

10.1.  Normative References

   [AES]      National Institute of Standards and Technology,
              "Specification for the Advanced Encryption Standard
              (AES)", FIPS 197, November 2001,
              <https://nvlpubs.nist.gov/nistpubs/fips/
              NIST.FIPS.197.pdf>.

   [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.cfm>.

   [DSS]      National Institute of Standards and Technology, "Digital
              Signature Standard (DSS)", NIST Federal Information
              Processing Standard 186-4, July 2013,
              <http://nvlpubs.nist.gov/nistpubs/FIPS/
              NIST.FIPS.186-4.pdf>.



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   [GCM]      National Institute of Standards and Technology,
              "Recommendation for Block Cipher Modes of Operation:
              Galois/Counter Mode (GCM) and GMAC", NIST Special
              Publication 800-38D, November 2007,
              <https://nvlpubs.nist.gov/nistpubs/Legacy/SP/
              nistspecialpublication800-38d.pdf>.

   [ID.dtls13]
              Rescorla, E., Tschofenig, H., and N. Modadugu, "The
              Datagram Transport Layer Security (DTLS) Protocol Version
              1.3", March 2019,
              <https://datatracker.ietf.org/doc/draft-ietf-tls-dtls13/>.

              Work in progress.

   [PWKE-A]   National Institute of Standards and Technology,
              "Recommendation for Pair-Wise Key Establishment Schemes
              Using Discrete Logarithm Cryptography", NIST Special
              Publication 800-56A, Revision 3, April 2018,
              <https://nvlpubs.nist.gov/nistpubs/SpecialPublications/
              NIST.SP.800-56Ar3.pdf>.

   [PWKE-B]   National Institute of Standards and Technology,
              "Recommendation for Pair-Wise Key Establishment Schemes
              Using Integer Factorization Cryptography", NIST Special
              Publication 800-56B, Revision 2, March 2019,
              <https://nvlpubs.nist.gov/nistpubs/SpecialPublications/
              NIST.SP.800-56Br2.pdf>.

   [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>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/info/rfc5246>.

   [RFC5288]  Salowey, J., Choudhury, A., and D. McGrew, "AES Galois
              Counter Mode (GCM) Cipher Suites for TLS", RFC 5288,
              DOI 10.17487/RFC5288, August 2008,
              <https://www.rfc-editor.org/info/rfc5288>.

   [RFC5289]  Rescorla, E., "TLS Elliptic Curve Cipher Suites with SHA-
              256/384 and AES Galois Counter Mode (GCM)", RFC 5289,
              DOI 10.17487/RFC5289, August 2008,
              <https://www.rfc-editor.org/info/rfc5289>.



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   [RFC6066]  Eastlake 3rd, D., "Transport Layer Security (TLS)
              Extensions: Extension Definitions", RFC 6066,
              DOI 10.17487/RFC6066, January 2011,
              <https://www.rfc-editor.org/info/rfc6066>.

   [RFC6347]  Rescorla, E. and N. Modadugu, "Datagram Transport Layer
              Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
              January 2012, <https://www.rfc-editor.org/info/rfc6347>.

   [RFC6961]  Pettersen, Y., "The Transport Layer Security (TLS)
              Multiple Certificate Status Request Extension", RFC 6961,
              DOI 10.17487/RFC6961, June 2013,
              <https://www.rfc-editor.org/info/rfc6961>.

   [RFC7919]  Gillmor, D., "Negotiated Finite Field Diffie-Hellman
              Ephemeral Parameters for Transport Layer Security (TLS)",
              RFC 7919, DOI 10.17487/RFC7919, August 2016,
              <https://www.rfc-editor.org/info/rfc7919>.

   [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>.

   [RFC8422]  Nir, Y., Josefsson, S., and M. Pegourie-Gonnard, "Elliptic
              Curve Cryptography (ECC) Cipher Suites for Transport Layer
              Security (TLS) Versions 1.2 and Earlier", RFC 8422,
              DOI 10.17487/RFC8422, August 2018,
              <https://www.rfc-editor.org/info/rfc8422>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [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>.








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   [SHS]      National Institute of Standards and Technology, "Secure
              Hash Standard (SHS)", NIST Federal Information Processing
              Standard 180-4, August 2015,
              <https://nvlpubs.nist.gov/nistpubs/FIPS/
              NIST.FIPS.180-4.pdf>.

10.2.  Informative References

   [SECG]     Brown, D., "SEC 2: Recommended Elliptic Curve Domain
              Parameters", February 2010,
              <http://www.secg.org/download/aid-784/sec2-v2.pdf>.

   [SP80059]  National Institute of Standards and Technology, "Guideline
              for Identifying an Information System as a National
              Security System", Special Publication 800 59, August 2003,
              <https://nvlpubs.nist.gov/nistpubs/Legacy/SP/
              nistspecialpublication800-59.pdf>.

Author's Address

   Dorothy Cooley
   National Security Agency

   Email: decoole@nsa.gov



























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