JOSE-COSE HPKE Cookbook
draft-steele-jose-cose-hpke-cookbook-00

Javascript Object Signing and Encryption                       O. Steele
Internet-Draft                                                 Transmute
Intended status: Informational                              2 March 2024
Expires: 3 September 2024

                        JOSE-COSE HPKE Cookbook
                draft-steele-jose-cose-hpke-cookbook-00

Abstract

   This document contains a set of examples using JSON Object Signing
   and Encryption (JOSE), CBOR Object Signing and Encryption (COSE) and
   Hybrid Public Key Encryption (HPKE) to protect data.  These examples
   are meant to coverage the edge cases of both JOSE and COSE, including
   different structures for single and multiple recipients, external
   additional authenticated data, and key derivation function (KDF)
   context binding.

About This Document

   This note is to be removed before publishing as an RFC.

   The latest revision of this draft can be found at
   https://OR13.github.io/draft-steele-jose-cose-hpke-cookbook/draft-
   steele-jose-cose-hpke-cookbook.html.  Status information for this
   document may be found at https://datatracker.ietf.org/doc/draft-
   steele-jose-cose-hpke-cookbook/.

   Discussion of this document takes place on the Javascript Object
   Signing and Encryption Working Group mailing list
   (mailto:jose@ietf.org), which is archived at
   https://mailarchive.ietf.org/arch/browse/jose/.  Subscribe at
   https://www.ietf.org/mailman/listinfo/jose/.

   Source for this draft and an issue tracker can be found at
   https://github.com/OR13/draft-steele-jose-cose-hpke-cookbook.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

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   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   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 3 September 2024.

Copyright Notice

   Copyright (c) 2024 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 carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Private Key . . . . . . . . . . . . . . . . . . . . . . .   3
       3.1.1.  application/jwk+json  . . . . . . . . . . . . . . . .   4
       3.1.2.  application/cose-key  . . . . . . . . . . . . . . . .   4
     3.2.  Direct Encryption . . . . . . . . . . . . . . . . . . . .   5
       3.2.1.  application/jose+json . . . . . . . . . . . . . . . .   5
       3.2.2.  application/cose  . . . . . . . . . . . . . . . . . .   6
     3.3.  Key Encryption  . . . . . . . . . . . . . . . . . . . . .   7
       3.3.1.  application/jose+json . . . . . . . . . . . . . . . .   7
       3.3.2.  application/cose  . . . . . . . . . . . . . . . . . .   8
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  11
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   This document is inspired by Examples of Protecting Content Using
   JSON Object Signing and Encryption (JOSE) [RFC7520].

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   JOSE support for HPKE is described in
   [I-D.draft-rha-jose-hpke-encrypt].

   COSE support for HPKE is described in [I-D.draft-ietf-cose-hpke].

   Both drafts are still work in progress.

   The current set of examples are incomplete.

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.

   The term "JSON Web Key (JWK)" is defined in [RFC7517].

   The term "COSE Key" is defined in [RFC9052].

   The terms "JSON Web Encryption (JWE)", "Direct Key Agreement", "Key
   Agreement with Key Wrapping", "JWE Compact Serialization" and
   "General JWE JSON Serialization" are defined in [RFC7516].

   The terms "Direct Encryption", and "Key Agreement with Key Wrap" are
   defined in [RFC9052].

   The term "encapsulated key" is defined in [RFC9180].

   This document does not define any new terms for JOSE or COSE.

3.  Overview

   Note that JSON (JavaScript Object Notation) and EDN (Extended
   Diagnostic Notation) may not exactly match the bytes provided for
   each example.

   The hexadecimal encoded binary messages are the source of truth, the
   JSON and EDN examples are for readability.

   NOTE: '' line wrapping per [RFC8792] in HTTP examples.

3.1.  Private Key

   This section provides private key representations that are used
   throught the following sections.

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   Public key representations for these keys are left as an excercise
   for the reader.

   The keys in this section are restricted to a single algorithm in both
   JOSE and COSE: HPKE-Base-P256-SHA256-AES128GCM.

   Additional algorithms and their private key representations may be
   provided in future versions of this draft.

3.1.1.  application/jwk+json

   This section provides a JSON Web Key for HPKE-Base-
   P256-SHA256-AES128GCM.

 7b0a2020226b6964223a202275726e3a696574663a706172616d733a6f617574683a6a\
 776b2d7468756d627072696e743a7368612d3235363a374a76784b756a755770596c4b\
 49455f75726479543749457165345030635a33476d3163364554526c5130222c0a2020\
 22616c67223a202248504b452d426173652d503235362d5348413235362d4145533132\
 3847434d222c0a2020226b7479223a20224543222c0a202022637276223a2022502d32\
 3536222c0a20202278223a2022646f37595f507a6f6c355f47326650686f50676f4f6f\
 306b6b34632d386745386952345958715449596d34222c0a20202279223a2022616b6a\
 4d396b56327a317057364b544c657148426b6d6d355332496d5f4f794f37526a527267\
 6d66316455222c0a20202264223a20224b583649304a7554664430467231703243646c\
 5239636f6e324851737759344673716a33437a533261704d220a7d

                      Figure 1: JSON Web Key Bytes

   {
     "kid": "urn:ietf:params:oauth:jwk-thumbprint:sha-256:7JvxKujuWpYlKIE_urdyT7IEqe4P0cZ3Gm1c6ETRlQ0",
     "alg": "HPKE-Base-P256-SHA256-AES128GCM",
     "kty": "EC",
     "crv": "P-256",
     "x": "do7Y_Pzol5_G2fPhoPgoOo0kk4c-8gE8iR4YXqTIYm4",
     "y": "akjM9kV2z1pW6KTLeqHBkmm5S2Im_OyO7RjRrgmf1dU",
     "d": "KX6I0JuTfD0Fr1p2CdlR9con2HQswY4Fsqj3CzS2apM"
   }

                           Figure 2: JSON Web Key

3.1.2.  application/cose-key

   This section provides a COSE Key for HPKE-Base-P256-SHA256-AES128GCM.

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  a702784d75726e3a696574663a706172616d733a6f617574683a636b743a7368612d3\
  235363a4b565f3339384668506158773761514d55595f4e5a497a7364416a7341544b\
  7a73765a6f333058424e514d03182301022001215820768ed8fcfce8979fc6d9f3e1a\
  0f8283a8d2493873ef2013c891e185ea4c8626e2258206a48ccf64576cf5a56e8a4cb\
  7aa1c19269b94b6226fcec8eed18d1ae099fd5d5235820297e88d09b937c3d05af5a7\
  609d951f5ca27d8742cc18e05b2a8f70b34b66a93

                         Figure 3: COSE Key Bytes

   {
     / kid / 2: "urn:ietf:params:oauth:ckt:sha-256:KV_398FhPaXw7aQMUY_NZIzsdAjsATKzsvZo30XBNQM",
     / alg: ES256 /  3: 35,
     / kty: EC2   /  1: 2,
     / crv: P-256 / -1: 1,
     / x / -2: h'768ed8fcfce8979fc6d9f3e1a0f8283a8d2493873ef2013c891e185ea4c8626e',
     / y / -3: h'6a48ccf64576cf5a56e8a4cb7aa1c19269b94b6226fcec8eed18d1ae099fd5d5',
     / d / -4: h'297e88d09b937c3d05af5a7609d951f5ca27d8742cc18e05b2a8f70b34b66a93'
   }

                       Figure 4: COSE Key Diagnostic

3.2.  Direct Encryption

   JOSE and COSE HPKE both support a "Direct Encryption Mode", where
   HPKE encrypt a plaintext message and optional additional
   authenticated data directly to a recipient public key.

   Note that HPKE Direct Encryption is not exactly the same as "Direct
   Encryption" as described in [RFC7516] and [RFC9052].

   In this section we provide direct encryption examples to the private
   keys in the previous section.

   ⌛ My lungs taste the air of Time Blown past falling sands ⌛

                    Figure 5: Direct Encryption Message

   ✨ It’s a dangerous business, Frodo, going out your door. ✨

                      Figure 6: Direct Encryption AAD

3.2.1.  application/jose+json

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 7b0a20202270726f746563746564223a202265794a68624763694f694a6b615849694c\
 434a6c626d4d694f694a49554574464c554a6863325574554449314e69315453454579\
 4e545974515556544d54493452304e4e496977695a584272496a7037496d7430655349\
 36496b564c496977695a5773694f694a43526d466a593073795546687859586c615130\
 3078526b68366245307a4d6a46584e3268334d6a56485557677751544974616e426163\
 553479516e564654575253595746464d7a5a7856306b315a5446766346687161474e4f\
 56575234643164435a334e5a596b4e7056456f7a65453579537a5169665830222c0a20\
 2022616164223a20223470796f49456c30346f435a6379426849475268626d646c636d\
 39316379426964584e70626d567a63797767526e4a765a473873494764766157356e49\
 47393164434235623356794947527662334975494f4b637141222c0a20202263697068\
 657274657874223a20226449326b4b2d6634787634446d45647848706e4f474130732d\
 695f4338735059444d3674664a456f6a6c6b5351355865586f41755151566d587a6479\
 754c6255476a69416a6967744e3455414a556b556f2d55673430695771435632544662\
 326e586579566436456167220a7d

                 Figure 7: JOSE Direct Encryption Bytes

   {
     "protected": "eyJhbGciOiJkaXIiLCJlbmMiOiJIUEtFLUJhc2UtUDI1Ni1TSEEyNTYtQUVTMTI4R0NNIiwiZXBrIjp7Imt0eSI6IkVLIiwiZWsiOiJCRmFjY0syUFhxYXlaQ00xRkh6bE0zMjFXN2h3MjVHUWgwQTItanBacU4yQnVFTWRSYWFFMzZxV0k1ZTFvcFhqaGNOVWR4d1dCZ3NZYkNpVEozeE5ySzQifX0",
     "aad": "4pyoIEl04oCZcyBhIGRhbmdlcm91cyBidXNpbmVzcywgRnJvZG8sIGdvaW5nIG91dCB5b3VyIGRvb3IuIOKcqA",
     "ciphertext": "dI2kK-f4xv4DmEdxHpnOGA0s-i_C8sPYDM6tfJEojlkSQ5XeXoAuQQVmXzdyuLbUGjiAjigtN4UAJUkUo-Ug40iWqCV2TFb2nXeyVd6Eag"
   }

                      Figure 8: JOSE Direct Encryption

   {
     "alg": "dir",
     "enc": "HPKE-Base-P256-SHA256-AES128GCM",
     "epk": {
       "kty": "EK",
       "ek": "BFaccK2PXqayZCM1FHzlM321W7hw25GQh0A2-jpZqN2BuEMdRaaE36qWI5e1opXjhcNUdxwWBgsYbCiTJ3xNrK4"
     }
   }

         Figure 9: JOSE Direct Encryption Decoded Protected Header

3.2.2.  application/cose

  d08344a1011823a204784d75726e3a696574663a706172616d733a6f617574683a636\
  b743a7368612d3235363a4b565f3339384668506158773761514d55595f4e5a497a73\
  64416a7341544b7a73765a6f333058424e514d235841048024424acb8a77edfbc461b\
  c4947e5d3ac3e5d31bc5f8a9fe71d0e4ef79f4b27943418a3817a14f6de06b43b98ce\
  ac551d4cf47e888293a271a9117db7abf19a584f693181d2479aca080d3e71ce37624\
  10665415cab2b831cac4fef97105cdec3b3a71de61019ceb0431d1637de54bab7f855\
  fe8bae7bd9ba5cc12a20d458baf08f4cf861da4a831964745eceb97f3bbf

                 Figure 10: COSE Direct Encryption Bytes

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   16([ / Single Recipient Encryption /
     h'a1011823', / Protected Header
     { / Unprotected Header /
       / kid / 4: "urn:ietf:params:oauth:ckt:sha-256:KV_398FhPaXw7aQMUY_NZIzsdAjsATKzsvZo30XBNQM",
       / ek / -4: h'048024424acb8a77edfbc461bc4947e5d3ac3e5d31bc5f8a9fe71d0e4ef79f4b27943418a3817a14f6de06b43b98ceac551d4cf47e888293a271a9117db7abf19a'
     },
     h'693181d2479aca080d3e71ce3762410665415cab2b831cac4fef97105cdec3b3a71de61019ceb0431d1637de54bab7f855fe8bae7bd9ba5cc12a20d458baf08f4cf861da4a831964745eceb97f3bbf'
   ])

                Figure 11: COSE Direct Encryption Diagnostic

   Note that JOSE and COSE transport the encapsulated key "ek"
   differently.

3.3.  Key Encryption

   JOSE and COSE HPKE both support a "Key Encryption Mode", where HPKE
   encrypt a content encryption key to a recipient public key, and a
   plaintext message and optional additional authenticated with the
   content encryption key.

   Note that HPKE Key Encryption Mode is not exactly the same as "Key
   Agreement with Key Wrap" as described in [RFC7516] and [RFC9052].

   In this section we provide direct encryption examples to the private
   keys in the previous section.

   ⌛ My lungs taste the air of Time Blown past falling sands ⌛

                     Figure 12: Key Encryption Message

   ✨ It’s a dangerous business, Frodo, going out your door. ✨

                       Figure 13: Key Encryption AAD

3.3.1.  application/jose+json

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  7b0a20202270726f746563746564223a202265794a6c626d4d694f694a424d5449345\
  2304e4e496977695a584272496a7037496d743065534936496b564c496977695a5773\
  694f694a43526b524862456f77533045774e3364305a454668543270445644557a564\
  5314c546e4266595578504f4467794d30525954314d32533370525557396e63555256\
  576a6832515768335355396e513035345a574d78545735575345563361556c4d4d6e7\
  07963334a50526d786b5255746865453069665830222c0a202022656e637279707465\
  645f6b6579223a202274774d563367697a4c7a5f74674455425831564b2d505a6a6b2\
  d503737415845745442445a44444c423973222c0a2020226976223a20223178716256\
  53586e6654524253675947222c0a20202263697068657274657874223a20225a5f546\
  6517a684643355a2d394a2d4f6b41676632784535364d75584b5f6b69793569594935\
  4a444e6c76474e794338534856754a7956346e5a6e7867396e624953525a7561477a7\
  8594971355a745469614434222c0a202022746167223a202259696844336762695a69\
  47624458662d5851434d7241222c0a202022616164223a20223470796f49456c30346\
  f435a6379426849475268626d646c636d39316379426964584e70626d567a63797767\
  526e4a765a473873494764766157356e4947393164434235623356794947527662334\
  975494f4b637141220a7d

                   Figure 14: JOSE Key Encryption Bytes

   {
     "protected": "eyJlbmMiOiJBMTI4R0NNIiwiZXBrIjp7Imt0eSI6IkVLIiwiZWsiOiJCRkRHbEowS0EwN3d0ZEFhT2pDVDUzVE1LTnBfYUxPODgyM0RYT1M2S3pRUW9ncURVWjh2QWh3SU9nQ054ZWMxTW5WSEV3aUlMMnpyc3JPRmxkRUtheE0ifX0",
     "encrypted_key": "twMV3gizLz_tgDUBX1VK-PZjk-P77AXEtTBDZDDLB9s",
     "iv": "1xqbVSXnfTRBSgYG",
     "ciphertext": "Z_TfQzhFC5Z-9J-OkAgf2xE56MuXK_kiy5iYI5JDNlvGNyC8SHVuJyV4nZnxg9nbISRZuaGzxYIq5ZtTiaD4",
     "tag": "YihD3gbiZiGbDXf-XQCMrA",
     "aad": "4pyoIEl04oCZcyBhIGRhbmdlcm91cyBidXNpbmVzcywgRnJvZG8sIGdvaW5nIG91dCB5b3VyIGRvb3IuIOKcqA"
   }

                    Figure 15: JOSE Key Encryption JSON

   {
     "enc": "A128GCM",
     "epk": {
       "kty": "EK",
       "ek": "BFDGlJ0KA07wtdAaOjCT53TMKNp_aLO8823DXOS6KzQQogqDUZ8vAhwIOgCNxec1MnVHEwiIL2zrsrOFldEKaxM"
     }
   }

          Figure 16: JOSE Key Encryption Decoded Protected Header

   Note that the ephemeral public key (epk) is present in the protected
   header due to there only being a single recipient for this message.

3.3.2.  application/cose

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  d8608443a10101a10550335552a987fd47dc85016ccc760bb541584fa0d7678a14400\
  1cc48d1ff514545df9e0da6b696a8ed3bceb529b78ba86c26bef93767d07b0111a48e\
  38dd79bfe9c351d6508ec2805b30ea16f6b46156e3ba9cffc11a39c311554970c7bda\
  a40d4c1818344a1011823a204784d75726e3a696574663a706172616d733a6f617574\
  683a636b743a7368612d3235363a4b565f3339384668506158773761514d55595f4e5\
  a497a7364416a7341544b7a73765a6f333058424e514d235841044e733517b62d8cf9\
  00d3d84606f8907bea0e3481c123359197782f0869b36c0efe13e76ae4740bcaf2f7a\
  f1e03523efe1b98dc4b81a94d45d9dfea583ef14e0f582000871c2c5f6a8b73aab9cf\
  df26953dc026036f00a08b61d903dd4a72e9c01229

                   Figure 17: COSE Key Encryption Bytes

   96([ / Multiple Recipient Encrypted Message /
     h'a10101',  / Protected Header /
     {
       / IV / 5: h'335552a987fd47dc85016ccc760bb541'
     },
     / Ciphertext / h'a0d7678a144001cc48d1ff514545df9e0da6b696a8ed3bceb529b78ba86c26bef93767d07b0111a48e38dd79bfe9c351d6508ec2805b30ea16f6b46156e3ba9cffc11a39c311554970c7bdaa40d4c1',
     [ / Recipients /
       [ / Recipient 0 /
         h'a1011823',  / Recipient Protected Header /
         { / Recipient Unprotected Header /
           / kid /  4: "urn:ietf:params:oauth:ckt:sha-256:KV_398FhPaXw7aQMUY_NZIzsdAjsATKzsvZo30XBNQM",
           / ek  / -4: h'044e733517b62d8cf900d3d84606f8907bea0e3481c123359197782f0869b36c0efe13e76ae4740bcaf2f7af1e03523efe1b98dc4b81a94d45d9dfea583ef14e0f'
         },
         / encrypted key / h'00871c2c5f6a8b73aab9cfdf26953dc026036f00a08b61d903dd4a72e9c01229'
       ]
     ]
   ])

                 Figure 18: COSE Key Encryption Diagnostic

4.  Security Considerations

   TODO Security

5.  IANA Considerations

   This document has no IANA actions.

6.  References

6.1.  Normative References

   [I-D.draft-ietf-cose-hpke]
              Tschofenig, H., Steele, O., Daisuke, A., and L. Lundblade,
              "Use of Hybrid Public-Key Encryption (HPKE) with CBOR
              Object Signing and Encryption (COSE)", Work in Progress,

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              Internet-Draft, draft-ietf-cose-hpke-07, 22 October 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-cose-
              hpke-07>.

   [I-D.draft-rha-jose-hpke-encrypt]
              Reddy.K, T., Tschofenig, H., Banerjee, A., Steele, O., and
              M. B. Jones, "Use of Hybrid Public-Key Encryption (HPKE)
              with Javascript Object Signing and Encryption (JOSE)",
              Work in Progress, Internet-Draft, draft-rha-jose-hpke-
              encrypt-05, 2 March 2024,
              <https://datatracker.ietf.org/doc/html/draft-rha-jose-
              hpke-encrypt-05>.

   [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/rfc/rfc2119>.

   [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/rfc/rfc8174>.

6.2.  Informative References

   [RFC7516]  Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)",
              RFC 7516, DOI 10.17487/RFC7516, May 2015,
              <https://www.rfc-editor.org/rfc/rfc7516>.

   [RFC7517]  Jones, M., "JSON Web Key (JWK)", RFC 7517,
              DOI 10.17487/RFC7517, May 2015,
              <https://www.rfc-editor.org/rfc/rfc7517>.

   [RFC7520]  Miller, M., "Examples of Protecting Content Using JSON
              Object Signing and Encryption (JOSE)", RFC 7520,
              DOI 10.17487/RFC7520, May 2015,
              <https://www.rfc-editor.org/rfc/rfc7520>.

   [RFC8792]  Watsen, K., Auerswald, E., Farrel, A., and Q. Wu,
              "Handling Long Lines in Content of Internet-Drafts and
              RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020,
              <https://www.rfc-editor.org/rfc/rfc8792>.

   [RFC9052]  Schaad, J., "CBOR Object Signing and Encryption (COSE):
              Structures and Process", STD 96, RFC 9052,
              DOI 10.17487/RFC9052, August 2022,
              <https://www.rfc-editor.org/rfc/rfc9052>.

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Internet-Draft           JOSE-COSE HPKE Cookbook              March 2024

   [RFC9180]  Barnes, R., Bhargavan, K., Lipp, B., and C. Wood, "Hybrid
              Public Key Encryption", RFC 9180, DOI 10.17487/RFC9180,
              February 2022, <https://www.rfc-editor.org/rfc/rfc9180>.

Acknowledgments

   TODO acknowledge.

Author's Address

   Orie Steele
   Transmute
   Email: orie@transmute.industries

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