Clarification of RFC7030 CSR Attributes definition
draft-ietf-lamps-rfc7030-csrattrs-09

LAMPS Working Group                                   M. Richardson, Ed.
Internet-Draft                                  Sandelman Software Works
Updates: 7030 (if approved)                                     O. Friel
Intended status: Standards Track                                   Cisco
Expires: 6 October 2024                                    D. von Oheimb
                                                                 Siemens
                                                              D. Harkins
                                                   The Industrial Lounge
                                                            4 April 2024

           Clarification of RFC7030 CSR Attributes definition
                  draft-ietf-lamps-rfc7030-csrattrs-09

Abstract

   The Enrollment over Secure Transport (EST, RFC7030) is ambiguous in
   its specification of the CSR Attributes Response.  This has resulted
   in implementation challenges and implementor confusion.

   This document updates RFC7030 (EST) and clarifies how the CSR
   Attributes Response can be used by an EST server to specify both CSR
   attribute OIDs and also CSR attribute values, in particular X.509
   extension values, that the server expects the client to include in
   subsequent CSR request.

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/.

   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 6 October 2024.

Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Richardson, et al.       Expires 6 October 2024                 [Page 1]
Internet-Draft                  CSRAttrs                      April 2024

   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  CSR Attributes Handling . . . . . . . . . . . . . . . . . . .   3
     3.1.  Extensions to RFC 7030 section 2.6. . . . . . . . . . . .   3
     3.2.  Extensions to RFC 7030 section 4.5.2. . . . . . . . . . .   4
     3.3.  Alternative: Use of CSR templates . . . . . . . . . . . .   5
   4.  Co-existence with existing implementations  . . . . . . . . .   6
   5.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     5.1.  RFC8994/ACP subjectAltName with specific otherName  . . .   6
       5.1.1.  Base64 encoded example  . . . . . . . . . . . . . . .   7
       5.1.2.  ASN.1 DUMP output . . . . . . . . . . . . . . . . . .   7
     5.2.  RFC7030 original example  . . . . . . . . . . . . . . . .   8
       5.2.1.  Base64 encoded example  . . . . . . . . . . . . . . .   8
       5.2.2.  ASN.1 DUMP output . . . . . . . . . . . . . . . . . .   8
     5.3.  EST server requires a specific subjectAltName
           extension . . . . . . . . . . . . . . . . . . . . . . . .   9
       5.3.1.  Base64 encoded example  . . . . . . . . . . . . . . .   9
       5.3.2.  ASN.1 DUMP output . . . . . . . . . . . . . . . . . .  10
     5.4.  Require a public key of a specific size . . . . . . . . .  12
       5.4.1.  Base64 encoded example  . . . . . . . . . . . . . . .  12
       5.4.2.  ASN.1 DUMP output . . . . . . . . . . . . . . . . . .  12
     5.5.  Require a public key of a specific curve  . . . . . . . .  12
       5.5.1.  Base64 encoded example  . . . . . . . . . . . . . . .  12
       5.5.2.  ASN.1 DUMP output . . . . . . . . . . . . . . . . . .  13
     5.6.  Require a specific extension  . . . . . . . . . . . . . .  13
       5.6.1.  Base64 encoded example  . . . . . . . . . . . . . . .  13
       5.6.2.  ASN.1 DUMP output . . . . . . . . . . . . . . . . . .  14
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  15
     6.1.  Identity and Privacy Considerations . . . . . . . . . . .  15
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  15
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  15
   9.  Changelog . . . . . . . . . . . . . . . . . . . . . . . . . .  15
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  15
     10.2.  Informative References . . . . . . . . . . . . . . . . .  17
   Appendix A.  ASN.1 Module . . . . . . . . . . . . . . . . . . . .  17
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  18

Richardson, et al.       Expires 6 October 2024                 [Page 2]
Internet-Draft                  CSRAttrs                      April 2024

1.  Introduction

   Enrollment over Secure Transport [RFC7030] (EST) has been used in a
   wide variety of applications.  In particular, [RFC8994] and [RFC8995]
   describe a way to use it in order to build out an autonomic control
   plane (ACP) [RFC8368].

   The ACP requires that each node be given a very specific
   subjectAltName.  In the ACP specification, the solution was for the
   EST server to use section 2.6 of [RFC7030] to convey to the EST
   client the actual subjectAltName that will end up in its certificate.

   As a result of some implementation challenges, it came to light that
   this particular way of using the CSR attributes was not universally
   agreed upon, and it was suggested that it went contrary to section
   2.6.

   Section 2.6 says that the CSR attributes "can provide additional
   descriptive information that the EST server cannot access itself".
   This is extended to describe how the EST server can provide values
   that it demands to use.

   After significant discussion, it has been determined that Section 4.5
   of [RFC7030] specification is sufficiently difficult to read and
   ambiguous to interpret that clarification is needed.

   This document motivates the different use cases, and provides
   additional worked out examples.

   Also, section 4.5.2 is extended to clarify the use of the existing
   ASN.1 syntax [X.680][X.690].  This covers all uses and is fully
   backward compatible with existing use.

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.

3.  CSR Attributes Handling

3.1.  Extensions to RFC 7030 section 2.6.

   Replace the second paragraph with the following text:

Richardson, et al.       Expires 6 October 2024                 [Page 3]
Internet-Draft                  CSRAttrs                      April 2024

   These attributes can provide additional descriptive information that
   the EST server cannot access itself, such as the Media Access Control
   (MAC) address of an interface of the EST client. The EST server can
   also provide concrete values that it tells the client to include in
   the CSR, such as a specific X.509 Subject Alternative Name extension.
   Moreover, these attributes can indicate the type of the included
   public key or which crypto algorithms to use for the self-signature,
   such as a specific elliptic curve or a specific hash function that
   the client is expected to use when generating the CSR.

3.2.  Extensions to RFC 7030 section 4.5.2.

   The ASN.1 syntax for CSR Attributes as defined in EST section 4.5.2
   is as follows:

      CsrAttrs ::= SEQUENCE SIZE (0..MAX) OF AttrOrOID

      AttrOrOID ::= CHOICE (oid OBJECT IDENTIFIER, attribute Attribute }

      Attribute { ATTRIBUTE:IOSet } ::= SEQUENCE {
           type   ATTRIBUTE.&id({IOSet}),
           values SET SIZE(1..MAX) OF ATTRIBUTE.&Type({IOSet}{@type}) }

   This remains unchanged, such that bits-on-the-wire compatibility is
   maintained.

   Key parts that were unclear were which OID to use in the 'type' field
   and that the 'values' field can contain an entire sequence of X.509
   extensions.

   The OID to use for such attributes in the 'type' field MUST be
   extensionRequest, which has the numerical value
   1.2.840.113549.1.9.14.  There MUST be only one such Attribute.

   The 'values' field of this attribute MUST contain a set with exactly
   one element, and this element MUST be of type Extensions, as per
   Section 4.1 of [RFC5280]:

      Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension

      Extension  ::=  SEQUENCE  {
           extnID      OBJECT IDENTIFIER,
           critical    BOOLEAN DEFAULT FALSE,
           extnValue   OCTET STRING
                       -- contains the DER encoding of an ASN.1 value
                       -- corresponding to the extension type identified
                       -- by extnID
           }

Richardson, et al.       Expires 6 October 2024                 [Page 4]
Internet-Draft                  CSRAttrs                      April 2024

   An Extension comprises the OID of the specific X.509 extension
   (extnID), optionally the 'critical' bit, and the extension value
   (extnValue).

   An Extensions structure, which is a sequence of elements of type
   Extension, MUST NOT include more than one element with a particiular
   extnID.

   With this understanding, the needs of [RFC8994] and [RFC8995] are
   satisfied with no change to the bits on the wire.

3.3.  Alternative: Use of CSR templates

   [RFC8295], Appendix B suggests an alternative that avoids the
   piecemeal inclusion of attributes that [RFC7030] documented.
   Instead, an entire CSR object is returned with various fields filled
   out, and other fields waiting to be filled in, in a pKCS7PDU
   attribute.  In the suggested approach, the pKCS7PDU attribute
   includes a Full PKI Data content type [RFC5272] and that in turn
   includes a CSR or CRMF formatted request; see [RFC6268] Sections 5
   and 9, respectively.

   The drawback to this approach, particularly for the CSR, is that some
   required fields are "faked"; specifically, the signature field on the
   CSR is faked with an empty bit string.  To avoid this drawback, this
   specification defines the Certificate Request Information Template
   attribute for CsrAttrs, see Section 3.2, that is request minus the
   useless signature wrapper as follows:

     aa-certificationRequestInfoTemplate ATTRIBUTE ::=
       { TYPE CertificationRequestInfoTemplate IDENTIFIED BY
         id-aa-certificationRequestInfoTemplate }

     id-aa-certificationRequestInfoTemplate OBJECT IDENTIFIER ::=
       { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
         smime(16) aa(2) csrinfo(TBD2) }

     CertificateRequestInfoTemplate ::= CertificationRequestInfo

   The CertificationRequestInfoTemplate uses the
   CertificationRequestInfo from [RFC5912], Section 5 and is included
   here for convenience:

Richardson, et al.       Expires 6 October 2024                 [Page 5]
Internet-Draft                  CSRAttrs                      April 2024

     CertificationRequestInfo ::= SEQUENCE {
       version       INTEGER { v1(0) } (v1,...),
       subject       Name,
       subjectPKInfo SubjectPublicKeyInfo{{ PKInfoAlgorithms }},
       attributes    [0] Attributes{{ CRIAttributes }}
     }

   Note: This method has also been defined in CMP Updates [RFC9480] and
   the Lightweight CMP profile [RFC9483], Section 4.3.3, using a CSR
   template as defined for CRMF [RFC4211].

   Legacy servers MAY continue to use the [RFC7030] style piecemeal
   attribute/value pairs, and MAY also include the template style
   described here.  Clients which understand both MUST use the template
   only, and ignore all other CSRattrs elements.  Older clients will
   ignore this new element.

   The version code is always v1 (0).  As shown in the example below,
   any empty values in the subject DN, and in any included X509v3
   extensions are expected to be filled in by the client.

   The SubjectPublicKeyInfo field MUST be present, but it MUST have an
   empty bit string for the key, as the server does not know what key
   will be used.  The server MAY specify (in the OID), the type of the
   key to use, but otherwise the OID type MUST be NULL.

   Each of the attributes has a single attribute value instance in the
   values set.  Even though the syntax is defined as a set, there MUST
   be exactly one instance of AttributeValue present.

4.  Co-existence with existing implementations

5.  Examples

   Each example has a high-level (English) explanation of what is
   expected.  Some mapping back to the Attribute and Extension
   definitions above are included.  The base64 DER encoding is then
   shown.  The output of "dumpasn1" is then provided to detail what the
   contents are.

5.1.  RFC8994/ACP subjectAltName with specific otherName

   A single subjectAltName extension is specified in a single Extension
   attribute.  This is what might be created by an [RFC8995] Registrar
   that is asking for [RFC8994] AcpNodeName format otherNames.

Richardson, et al.       Expires 6 October 2024                 [Page 6]
Internet-Draft                  CSRAttrs                      April 2024

5.1.1.  Base64 encoded example

   The Base64:

   MGQwYgYJKoZIhvcNAQkOMVUwUwYDVR0RAQH/BEmgRzBFBggr
   BgEFBQcICgw5cmZjODk5NCtmZDczOWZjMjNjMzQ0MDExMjIz
   MzQ0NTUwMDAwMDAwMCtAYWNwLmV4YW1wbGUuY29t

5.1.2.  ASN.1 DUMP output

   There is a single subjectAltName Extension with an Attribute with
   Extension type.

     <30 64>
   0 100: SEQUENCE {
     <30 62>
   2  98:   SEQUENCE {
     <06 09>
   4   9:     OBJECT IDENTIFIER extensionRequest (1 2 840 113549 1 9 14)
        :       (PKCS #9 via CRMF)
     <31 55>
  15  85:     SET {
     <30 53>
  17  83:       SEQUENCE {
     <06 03>
  19   3:         OBJECT IDENTIFIER subjectAltName (2 5 29 17)
        :           (X.509 extension)
     <01 01>
  24   1:         BOOLEAN TRUE
     <04 49>
  27  73:         OCTET STRING
        :           A0 47 30 45 06 08 2B 06    .G0E..+.
        :           01 05 05 07 08 0A 0C 39    .......9
        :           72 66 63 38 39 39 34 2B    rfc8994+
        :           66 64 37 33 39 66 63 32    fd739fc2
        :           33 63 33 34 34 30 31 31    3c344011
        :           32 32 33 33 34 34 35 35    22334455
        :           30 30 30 30 30 30 30 30    00000000
        :           2B 40 61 63 70 2E 65 78    +@acp.ex
        :           61 6D 70 6C 65 2E 63 6F    ample.co
        :           6D                         m
        :         }
        :       }
        :     }
        :   }

Richardson, et al.       Expires 6 October 2024                 [Page 7]
Internet-Draft                  CSRAttrs                      April 2024

5.2.  RFC7030 original example

   In this example, taken from [RFC7030], a few different attributes are
   included.

5.2.1.  Base64 encoded example

   The Base64:

   MEEGCSqGSIb3DQEJBzASBgcqhkjOPQIBMQcGBSuBBAAiMBYG
   CSqGSIb3DQEJDjEJBgcrBgEBAQEWBggqhkjOPQQDAw==

5.2.2.  ASN.1 DUMP output

   1.  The challengePassword attribute is included to indicate that the
       CSR should include this value.

   2.  An ecPublicKey attribute is provided with the value secp384r1 to
       indicate what kind of key should be submitted.

   3.  An extensionRequest container with an OID 1.3.6.1.1.1.1.22
       (macAddress), but without a value, to indicate that the CSR
       should include an X.509v3 extension with this value.

   4.  The ecdsaWithSHA384 OID is included to indicate what kind of hash
       is expected to be used for the self-signature of the PCKS#10 CSR
       structure.

Richardson, et al.       Expires 6 October 2024                 [Page 8]
Internet-Draft                  CSRAttrs                      April 2024

     <30 41>
   0  65: SEQUENCE {
     <06 09>
   2   9:   OBJECT IDENTIFIER challengePassword (1 2 840 113549 1 9 7)
        :     (PKCS #9)
     <30 12>
  13  18:   SEQUENCE {
     <06 07>
  15   7:     OBJECT IDENTIFIER ecPublicKey (1 2 840 10045 2 1)
        :       (ANSI X9.62 public key type)
     <31 07>
  24   7:     SET {
     <06 05>
  26   5:       OBJECT IDENTIFIER secp384r1 (1 3 132 0 34)
        :         (SECG (Certicom) named elliptic curve)
        :       }
        :     }
     <30 16>
  33  22:   SEQUENCE {
     <06 09>
  35   9:     OBJECT IDENTIFIER extensionRequest (1 2 840 113549 1 9 14)
        :       (PKCS #9 via CRMF)
     <31 09>
  46   9:     SET {
     <06 07>
  48   7:       OBJECT IDENTIFIER '1 3 6 1 1 1 1 22'
        :       }
        :     }
     <06 08>
  57   8:   OBJECT IDENTIFIER ecdsaWithSHA384 (1 2 840 10045 4 3 3)
        :     (ANSI X9.62 ECDSA algorithm with SHA384)
        :   }

5.3.  EST server requires a specific subjectAltName extension

   This example is the same as the previous one except that instead of
   the OID for a macAddress, a subjectAltName is specified as the only
   Extension element.

5.3.1.  Base64 encoded example

   The Base64:

   MGYGCSqGSIb3DQEJBzASBgcqhkjOPQIBMQcGBSuBBAAiMDsG
   CSqGSIb3DQEJDjEuMCwGA1UdEQEB/wQioCAwHgYIKwYBBQUH
   CAoMEnBvdGF0b0BleGFtcGxlLmNvbQYIKoZIzj0EAwM=

Richardson, et al.       Expires 6 October 2024                 [Page 9]
Internet-Draft                  CSRAttrs                      April 2024

5.3.2.  ASN.1 DUMP output

   1.  The challengePassword attribute is included to indicate that the
       CSR should include this value.

   2.  An ecPublicKey attribute is provided with the value secp384r1 to
       indicate what kind of key should be submitted.

   3.  An extensionRequest container with a subjectAltName value
       containing the name potato@example.com

   4.  The ecdsaWithSHA384 OID is included to indicate what kind of hash
       is expected to be used for the self-signature of the PCKS#10 CSR
       structure.

Richardson, et al.       Expires 6 October 2024                [Page 10]
Internet-Draft                  CSRAttrs                      April 2024

     <30 66>
   0 102: SEQUENCE {
     <06 09>
   2   9:   OBJECT IDENTIFIER challengePassword (1 2 840 113549 1 9 7)
        :     (PKCS #9)
     <30 12>
  13  18:   SEQUENCE {
     <06 07>
  15   7:     OBJECT IDENTIFIER ecPublicKey (1 2 840 10045 2 1)
        :       (ANSI X9.62 public key type)
     <31 07>
  24   7:     SET {
     <06 05>
  26   5:       OBJECT IDENTIFIER secp384r1 (1 3 132 0 34)
        :         (SECG (Certicom) named elliptic curve)
        :       }
        :     }
     <30 3B>
  33  59:   SEQUENCE {
     <06 09>
  35   9:     OBJECT IDENTIFIER extensionRequest (1 2 840 113549 1 9 14)
        :       (PKCS #9 via CRMF)
     <31 2E>
  46  46:     SET {
     <30 2C>
  48  44:       SEQUENCE {
     <06 03>
  50   3:         OBJECT IDENTIFIER subjectAltName (2 5 29 17)
        :           (X.509 extension)
     <01 01>
  55   1:         BOOLEAN TRUE
     <04 22>
  58  34:         OCTET STRING
        :           A0 20 30 1E 06 08 2B 06    . 0...+.
        :           01 05 05 07 08 0A 0C 12    ........
        :           70 6F 74 61 74 6F 40 65    potato@e
        :           78 61 6D 70 6C 65 2E 63    xample.c
        :           6F 6D                      om
        :         }
        :       }
        :     }
     <06 08>
  94   8:   OBJECT IDENTIFIER ecdsaWithSHA384 (1 2 840 10045 4 3 3)
        :     (ANSI X9.62 ECDSA algorithm with SHA384)
        :   }

Richardson, et al.       Expires 6 October 2024                [Page 11]
Internet-Draft                  CSRAttrs                      April 2024

5.4.  Require a public key of a specific size

   The CSR requires a public key of a specific size

5.4.1.  Base64 encoded example

   The Base64:

   MCkGCSqGSIb3DQEJBzARBgkqhkiG9w0BAQExBAICEAAGCSqG
   SIb3DQEBCw==

5.4.2.  ASN.1 DUMP output

   1.  Provide a CSR with an RSA key that's 4096 bits and sign it with
       sha256

       <30 29>
     0  41: SEQUENCE {
       <06 09>
     2   9:   OBJECT IDENTIFIER challengePassword (1 2 840 113549 1 9 7)
          :     (PKCS #9)
       <30 11>
    13  17:   SEQUENCE {
       <06 09>
    15   9:     OBJECT IDENTIFIER rsaEncryption (1 2 840 113549 1 1 1)
          :       (PKCS #1)
       <31 04>
    26   4:     SET {
       <02 02>
    28   2:       INTEGER 4096
          :       }
          :     }
       <06 09>
    32   9:   OBJECT IDENTIFIER sha256WithRSAEncryption
                                (1 2 840 113549 1 1 11)
          :     (PKCS #1)
          :   }

5.5.  Require a public key of a specific curve

   The CSR requires a public key with a specific curve

5.5.1.  Base64 encoded example

   The Base64:

   MD0GCSqGSIb3DQEJBzASBgcqhkjOPQIBMQcGBSuBBAAiMBIGCSqGSIb3DQEJDjEF
   BgNVBAUGCCqGSM49BAMD

Richardson, et al.       Expires 6 October 2024                [Page 12]
Internet-Draft                  CSRAttrs                      April 2024

5.5.2.  ASN.1 DUMP output

   Provide a CSR with an ECC key from p384, include your serial number,
   and sign it with sha384.

     <30 3D>
   0  61: SEQUENCE {
     <06 09>
   2   9:   OBJECT IDENTIFIER challengePassword (1 2 840 113549 1 9 7)
        :     (PKCS #9)
     <30 12>
  13  18:   SEQUENCE {
     <06 07>
  15   7:     OBJECT IDENTIFIER ecPublicKey (1 2 840 10045 2 1)
        :       (ANSI X9.62 public key type)
     <31 07>
  24   7:     SET {
     <06 05>
  26   5:       OBJECT IDENTIFIER secp384r1 (1 3 132 0 34)
        :         (SECG (Certicom) named elliptic curve)
        :       }
        :     }
     <30 12>
  33  18:   SEQUENCE {
     <06 09>
  35   9:     OBJECT IDENTIFIER extensionRequest (1 2 840 113549 1 9 14)
        :       (PKCS #9 via CRMF)
     <31 05>
  46   5:     SET {
     <06 03>
  48   3:       OBJECT IDENTIFIER serialNumber (2 5 4 5)
        :         (X.520 DN component)
        :       }
        :     }
     <06 08>
  53   8:   OBJECT IDENTIFIER ecdsaWithSHA384 (1 2 840 10045 4 3 3)
        :     (ANSI X9.62 ECDSA algorithm with SHA384)
        :   }

5.6.  Require a specific extension

   The CSR is required to have an EC key, to include a serial number, a
   friendly name, favorite drink, and be signed with SHA512.

5.6.1.  Base64 encoded example

   The Base64:

Richardson, et al.       Expires 6 October 2024                [Page 13]
Internet-Draft                  CSRAttrs                      April 2024

   MFQGCSqGSIb3DQEJBzASBgcqhkjOPQIBMQcGBSuBBAAjMCkG
   CSqGSIb3DQEJDjEcBgNVBAUGCSqGSIb3DQEJFAYKCZImiZPy
   LGQBBQYIKoZIzj0EAwQ=

5.6.2.  ASN.1 DUMP output

   Provide a CSR with an EC key from sha521, include your serial number,
   friendly name, and favorite drink, and sign it with sha512

     <30 54>
   0  84: SEQUENCE {
     <06 09>
   2   9:   OBJECT IDENTIFIER challengePassword (1 2 840 113549 1 9 7)
        :     (PKCS #9)
     <30 12>
  13  18:   SEQUENCE {
     <06 07>
  15   7:     OBJECT IDENTIFIER ecPublicKey (1 2 840 10045 2 1)
        :       (ANSI X9.62 public key type)
     <31 07>
  24   7:     SET {
     <06 05>
  26   5:       OBJECT IDENTIFIER secp521r1 (1 3 132 0 35)
        :         (SECG (Certicom) named elliptic curve)
        :       }
        :     }
     <30 29>
  33  41:   SEQUENCE {
     <06 09>
  35   9:     OBJECT IDENTIFIER extensionRequest (1 2 840 113549 1 9 14)
        :       (PKCS #9 via CRMF)
     <31 1C>
  46  28:     SET {
     <06 03>
  48   3:       OBJECT IDENTIFIER serialNumber (2 5 4 5)
        :         (X.520 DN component)
     <06 09>
  53   9:       OBJECT IDENTIFIER
        :         friendlyName (for PKCS #12) (1 2 840 113549 1 9 20)
        :         (PKCS #9 via PKCS #12)
     <06 0A>
  64  10:       OBJECT IDENTIFIER '0 9 2342 19200300 100 1 5'
        :       }
        :     }
     <06 08>
  76   8:   OBJECT IDENTIFIER ecdsaWithSHA512 (1 2 840 10045 4 3 4)
        :     (ANSI X9.62 ECDSA algorithm with SHA512)
        :   }

Richardson, et al.       Expires 6 October 2024                [Page 14]
Internet-Draft                  CSRAttrs                      April 2024

6.  Security Considerations

   The security considerations from EST [RFC7030] section 6 are
   unchanged.

6.1.  Identity and Privacy Considerations

   An EST server may use this mechanism to instruct the EST client about
   the identities it should include in the CSR it sends as part of
   enrollment.  The client may only be aware of its IDevID Subject,
   which includes a manufacturer serial number.  The EST server can use
   this mechanism to tell the client to include a specific fully
   qualified domain name in the CSR in order to complete domain
   ownership proofs required by the CA.  Additionally, the EST server
   may deem the manufacturer serial number in an IDevID as personally
   identifiable information, and may want to specify a new random opaque
   identifier that the pledge should use in its CSR.  This may be
   desirable if the CA and EST server have different operators.

7.  IANA Considerations

   IANA is asked to allocate two new Object Identifiers:

   *  One (TBD1) from the SMI Security for S/MIME Module Identifier
      (1.2.840.113549.1.9.16.0) registry for the ASN.1 module: id-mod-
      critemplate; see Appendix A, and

   *  One (TBD2) from the SMI Security for S/MIME Attributes
      (1.2.840.113549.1.9.16.2) registry for the Certification Request
      Information Template (csrinfo) attribute; see Section 3.3 and
      Appendix A.

8.  Acknowledgements

   Corey Bonnell crafted example02 using a different tool, and this
   helped debug other running code.

9.  Changelog

10.  References

10.1.  Normative References

   [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>.

Richardson, et al.       Expires 6 October 2024                [Page 15]
Internet-Draft                  CSRAttrs                      April 2024

   [RFC5272]  Schaad, J. and M. Myers, "Certificate Management over CMS
              (CMC)", RFC 5272, DOI 10.17487/RFC5272, June 2008,
              <https://www.rfc-editor.org/rfc/rfc5272>.

   [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/rfc/rfc5280>.

   [RFC5652]  Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
              RFC 5652, DOI 10.17487/RFC5652, September 2009,
              <https://www.rfc-editor.org/rfc/rfc5652>.

   [RFC5911]  Hoffman, P. and J. Schaad, "New ASN.1 Modules for
              Cryptographic Message Syntax (CMS) and S/MIME", RFC 5911,
              DOI 10.17487/RFC5911, June 2010,
              <https://www.rfc-editor.org/rfc/rfc5911>.

   [RFC5912]  Hoffman, P. and J. Schaad, "New ASN.1 Modules for the
              Public Key Infrastructure Using X.509 (PKIX)", RFC 5912,
              DOI 10.17487/RFC5912, June 2010,
              <https://www.rfc-editor.org/rfc/rfc5912>.

   [RFC6268]  Schaad, J. and S. Turner, "Additional New ASN.1 Modules
              for the Cryptographic Message Syntax (CMS) and the Public
              Key Infrastructure Using X.509 (PKIX)", RFC 6268,
              DOI 10.17487/RFC6268, July 2011,
              <https://www.rfc-editor.org/rfc/rfc6268>.

   [RFC7030]  Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
              "Enrollment over Secure Transport", RFC 7030,
              DOI 10.17487/RFC7030, October 2013,
              <https://www.rfc-editor.org/rfc/rfc7030>.

   [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>.

   [RFC8994]  Eckert, T., Ed., Behringer, M., Ed., and S. Bjarnason, "An
              Autonomic Control Plane (ACP)", RFC 8994,
              DOI 10.17487/RFC8994, May 2021,
              <https://www.rfc-editor.org/rfc/rfc8994>.

   [RFC8995]  Pritikin, M., Richardson, M., Eckert, T., Behringer, M.,
              and K. Watsen, "Bootstrapping Remote Secure Key
              Infrastructure (BRSKI)", RFC 8995, DOI 10.17487/RFC8995,
              May 2021, <https://www.rfc-editor.org/rfc/rfc8995>.

Richardson, et al.       Expires 6 October 2024                [Page 16]
Internet-Draft                  CSRAttrs                      April 2024

   [X.680]    ITU-T, "Information technology -- Abstract Syntax Notation
              One (ASN.1): Specification of basic notation", ITU-T
              Recommendation X.680, ISO/IEC 8824-1:2021, February 2021,
              <https://www.itu.int/rec/T-REC-X.680>.

   [X.690]    ITU-T, "Information technology -- ASN.1 encoding rules:
              Specification of Basic Encoding Rules (BER), Canonical
              Encoding Rules (CER) and Distinguished Encoding Rules
              (DER)", ITU-T Recommendation X.690, ISO/IEC 8825-1:2021,
              February 2021, <https://www.itu.int/rec/T-REC-X.680>.

10.2.  Informative References

   [RFC4211]  Schaad, J., "Internet X.509 Public Key Infrastructure
              Certificate Request Message Format (CRMF)", RFC 4211,
              DOI 10.17487/RFC4211, September 2005,
              <https://www.rfc-editor.org/rfc/rfc4211>.

   [RFC8295]  Turner, S., "EST (Enrollment over Secure Transport)
              Extensions", RFC 8295, DOI 10.17487/RFC8295, January 2018,
              <https://www.rfc-editor.org/rfc/rfc8295>.

   [RFC8368]  Eckert, T., Ed. and M. Behringer, "Using an Autonomic
              Control Plane for Stable Connectivity of Network
              Operations, Administration, and Maintenance (OAM)",
              RFC 8368, DOI 10.17487/RFC8368, May 2018,
              <https://www.rfc-editor.org/rfc/rfc8368>.

   [RFC9480]  Brockhaus, H., von Oheimb, D., and J. Gray, "Certificate
              Management Protocol (CMP) Updates", RFC 9480,
              DOI 10.17487/RFC9480, November 2023,
              <https://www.rfc-editor.org/rfc/rfc9480>.

   [RFC9483]  Brockhaus, H., von Oheimb, D., and S. Fries, "Lightweight
              Certificate Management Protocol (CMP) Profile", RFC 9483,
              DOI 10.17487/RFC9483, November 2023,
              <https://www.rfc-editor.org/rfc/rfc9483>.

Appendix A.  ASN.1 Module

      |  RFC EDITOR: Please replace TBD1 and TBD2 with the value
      |  assigned by IANA during the publication of [I-D.ietf-lamps-
      |  rfc7030-csrattrs].

   This appendix provides an ASN.1 module [X.680] for the Certification
   Request Information Template attribute, and it follows the
   conventions established in [RFC5911], [RFC5912], and [RFC6268].

Richardson, et al.       Expires 6 October 2024                [Page 17]
Internet-Draft                  CSRAttrs                      April 2024

   CRITemplateModule
     { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
       pkcs-9(9) smime(16) modules(0) id-mod-critemplate(TBD1) }

   DEFINITIONS IMPLICIT TAGS ::=

   BEGIN

   IMPORTS

   ATTRIBUTE -- [RFC5911]
    FROM PKIX-CommonTypes-2009
      { iso(1) identified-organization(3) dod(6) internet(1)
        security(5) mechanisms(5) pkix(7)
        id-mod(0) id-mod-pkixCommon-02(57) }

   CertificationRequestInfo -- [RFC5912]
     FROM PKCS-10
       { iso(1) identified-organization(3) dod(6) internet(1)
         security(5) mechanisms(5) pkix(7)
         id-mod(0) id-mod-pkcs10-2009(69) }

   ;

   aa-certificationRequestInfoTemplate ATTRIBUTE ::=
     { TYPE CertificationRequestInfoTemplate IDENTIFIED BY
       id-aa-certificationRequestInfoTemplate }

   id-aa-certificationRequestInfoTemplate OBJECT IDENTIFIER ::=
     { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
       smime(16) aa(2) csrinfo(TBD2) }

   CertificationRequestInfoTemplate ::= CertificationRequestInfo

   END

Authors' Addresses

   Michael Richardson (editor)
   Sandelman Software Works
   Email: mcr+ietf@sandelman.ca

   Owen Friel
   Cisco
   Email: ofriel@cisco.com

Richardson, et al.       Expires 6 October 2024                [Page 18]
Internet-Draft                  CSRAttrs                      April 2024

   Dr. David von Oheimb
   Siemens
   Email: dev@ddvo.net

   Dan Harkins
   The Industrial Lounge
   Email: dharkins@lounge.org

Richardson, et al.       Expires 6 October 2024                [Page 19]