CMP Updates
draft-ietf-lamps-cmp-updates-01

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Last updated 2020-03-04
Replaces draft-brockhaus-lamps-cmp-updates
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LAMPS Working Group                                         H. Brockhaus
Internet-Draft                                                   Siemens
Updates: 4210 (if approved)                                March 4, 2020
Intended status: Standards Track
Expires: September 5, 2020

                              CMP Updates
                    draft-ietf-lamps-cmp-updates-01

Abstract

   This document contains a set of updates to the base syntax of
   Certificate Management Protocol (CMP) version 2.  This document
   updates RFC 4210.

   Specifically, the CMP services updated in this document comprise the
   enabling of using EnvelopedData instead of EncryptedValue and the
   definition of extended key usages to identify certificates of CMP
   endpoints on certification and registration authorities.

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 September 5, 2020.

Copyright Notice

   Copyright (c) 2020 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

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   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.  History of changes  . . . . . . . . . . . . . . . . . . . . .   2
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Convention and Terminology  . . . . . . . . . . . . . . .   3
   3.  Updates to RFC 4210 - Certificate Management Protocol (CMP) .   4
     3.1.  New Section 1.1. - Changes since RFC 4210 . . . . . . . .   4
     3.2.  New Section 4.5 - Extended Key Usage  . . . . . . . . . .   5
     3.3.  Replace Section 5.1.3.4 - Multiple Protection . . . . . .   7
     3.4.  Replace Section 5.2.2. - Encrypted Values . . . . . . . .   8
     3.5.  Update Section 5.3.4. - Certification Response  . . . . .   9
     3.6.  Replace Section 5.3.19.9. - Revocation Passphrase . . . .  10
     3.7.  Update Section 5.3.22 - Polling Request and Response  . .  10
     3.8.  Update Appendix B - The Use of Revocation Passphrase  . .  11
     3.9.  Update Appendix C - Request Message Behavioral
           Clarifications  . . . . . . . . . . . . . . . . . . . . .  12
     3.10. Update Appendix D.4. - Initial Registration/Certification
           (Basic Authenticated Scheme)  . . . . . . . . . . . . . .  13
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  13
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  14
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  15
   Appendix A.  ASN.1 Modules  . . . . . . . . . . . . . . . . . . .  15
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  16

1.  History of changes

   From version 00 -> 01:

   o  Minor changes in wording

   From draft-brockhaus-lamps-cmp-updates-03 -> draft-ietf-lamps-cmp-
   updates-00:

   o  Changes required to reflect WG adoption

   From version 02 -> 03:

   o  Added some clarification in Section 3.1

   From version 01 -> 02:

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   o  Added clarification to section on multiple protection

   o  Added clarification on new EKUs after some exchange with Tomas
      Gustavsson

   o  Reused OIDs from RFC 6402 [RFC6402] as suggested by Sean Turner at
      IETF 106

   o  Added clarification on the field containing the key identifier for
      a revocation passphrase

   o  Minor changes in wording

   From version 00 -> 01:

   o  Added a section describing the new extended key usages

   o  Completed the section on changes to the specification of encrypted
      values

   o  Added a section on clarification to Appendix D.4

   o  Minor generalization in RFC 4210 [RFC4210] Sections 5.1.3.4 and
      5.3.22

   o  Minor changes in wording

2.  Introduction

   While using CMP [RFC4210] in industrial and IoT environments and
   developing the Lightweight CMP Profile
   [I-D.ietf-lamps-lightweight-cmp-profile] some limitations were
   identified in the original CMP specification.  This document updates
   RFC 4210 [RFC4210] to overcome these limitations.

   In general, this document aims to improve the crypto agility of CMP
   to be flexible to react on future advances in cryptography.

   This document also introduces new extended key usages to identify CMP
   endpoints on registration and certification authorities.

2.1.  Convention and Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

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   In this document, these words will appear with that interpretation
   only when in ALL CAPS.  Lower case uses of these words are not to be
   interpreted as carrying significance described in RFC 2119.

   Technical terminology is used in conformance with RFC 4210 [RFC4210],
   RFC 4211 [RFC4211], and RFC 5280 [RFC5280].  The following key words
   are used:

   CA:  Certification authority, which issues certificates.

   RA:  Registration authority, an optional system component to which a
        CA delegates certificate management functions such as
        authorization checks.

   KGA: Key generation authority, which generates key pairs on behalf of
        an EE.  The KGA could be co-located with an RA or a CA.

   EE:  End entity, a user, device, or service that holds a PKI
        certificate.  An identifier for the EE is given as its subject
        of the certificate.

3.  Updates to RFC 4210 - Certificate Management Protocol (CMP)

3.1.  New Section 1.1. - Changes since RFC 4210

   The following subsection describes feature updates to RFC 4210
   [RFC4210].  They are always related to the base specification.  Hence
   references to the original sections in RFC 4210 [RFC4210] are used
   whenever possible.

   Insert this section at the end of the current Section 1.

   1.1 Changes since RFC 4210

   The following updates are made in draft-ietf-lamps-cmp-updates:

   o  Add new extended key usages for different CMP server types, e.g.
      registration authority and certification authority, to express the
      authorization of the entity identified in the certificate
      containing the respective extended key usage extension to act as
      the indicated PKI management entity.

   o  Extend the description of multiple protection to cover additional
      use cases, e.g., batch processing of messages.

   o  Offering EnvelopedData as the prefered choice next to
      EncryptedValue to extend crypto agility in CMP.  Note that
      according to RFC 4211 [RFC4211] section 2.1.9 the use of the

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      EncryptedValue structure has been deprecated in favor of the
      EnvelopedData structure.  RFC 4211 [RFC4211] offers the
      EncryptedKey structure, a choice of EncryptedValue and
      EnvelopedData for migration to EnvelopedData.  For reasons of
      completeness and consistency the exchange of EncryptedValue is
      performed for all usages in RFC 4210 [RFC4210].  This includes the
      protection of centrally generated private keys, encryption of
      certificates, and revocation passphrases.

   o  Extend the usage of polling also to p10cr messages.

3.2.  New Section 4.5 - Extended Key Usage

   The following subsection describes new extended key usages for
   different CMP server typesspecitied in RFC 4210 [RFC4210].

   Insert this section at the end of the current Section 4.

   4.5 Extended Key Usage

   The Extended Key Usage (EKU) extension indicates the purposes for
   which the certified public key may be used.  It therefore restricts
   the use of a certificate to specific applications.

   A CA may want to delegate parts of their duties to other PKI
   management entities.  The mechanism to prove this delegation
   explained in this section offers zero-touch means to check the
   authorization of such delegation.  Such delegation could also be
   expressed by other means, e.g., explicit configuration.

   To offer automatic validation means for the delegation of a role by a
   CA, the certificates used by PKI management entities for CMP message
   protection or signed data for central key generation MUST be issued
   by the delegating CA and MUST contain the respective EKUs.  This
   proves the authorization of this entity by the delegating CA to act
   as the PKI management entity as described below.

   The ASN.1 to define these EKUs is:

   id-kp-cmpCA OBJECT IDENTIFIER ::= { id-kp 27 }
   id-kp-cmpRA OBJECT IDENTIFIER ::= { id-kp 28 }
   id-kp-cmpKGA OBJECT IDENTIFIER ::= { id-kp ... }

   < TBD: id-kp-cmpKGA to be defined. >

   Note: RFC 6402 section 2.10 [RFC6402] specifies OIDs for a CMC CA and
   a CMC RA.  As the functionality of a CA and RA is not specific to

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   whether use CMC or CMP as certificate management protocol, the same
   OIDs SHALL be used for a cmpCA and a cmpRA.

   < TBD: It needs to be clarified, if the Name and Description of the
   OIDs can be adapted or extended to avoid confusion as they currently
   only refer to CMC endpoints. >

   The description of the PKI management entity for each of the EKUs is
   as follows:

   cmpCA:  CMP Certification Authorities are CMP endpoints on CA
           equipment as described in section 3.1.1.2.  The key used in
           the context of CMP management operations, especially CMP
           message protection, need not be the same key that signs the
           certificates.  It is necessary, however, to ensure that the
           entity acting as cmpCA is authorized to do so.  Therefore,
           the cmpCA MUST do one of the following,

           *  use the CA private key on the CMP endpoint, or

           *  explicitly designate this authority to another entity.

           For automatic validation of such delegation it MUST be
           indicated by the id-kp-cmpCA extended key usage.  This
           extended key usage MUST be placed into the certificate used
           on the CA equipment and the CA that delegates this role MUST
           issue the cmpCA certificate.

           Note: Using a separate key pair for protecting CMP management
           operations at the CA decreases the number of operations of
           the private key used to sign certificates.

   cmpRA:  CMP Registration Authorities are CMP endpoints on RA
           equipment as described in Section 3.1.1.3.  A cmpRA is
           identified by the id-kp-cmpRA extended key usage.  This
           extended key usage is placed into RA certificates.  The CA
           that delegated this role is identified by the CA that issued
           the cmpRA certificate.

   cmpKGA: CMP Key Generation Authorities are identified by the id-kp-
           cmpKGA extended key usage.  Though the cmpKGA knows the
           private key it generated on behalf of the end entity.  This
           is a very sensible service and needs specific authorization.
           This authorization is either with the CA certificate itself,
           or indicated by placing the id-kp-cmpKGA extended key usage
           into the cmpRA or cmpCA certificate used to authenticate the
           origin of the private key, and to express the authorization
           to offer this service.

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   Note: In device PKIs, especially those issuing IDevID certificates,
   CA may have very long validity (including the GeneralizedTime value
   99991231235959Z to indicate a not well-defined expiration date as
   specified in IEEE 802.1AR Section 8.5 [IEEE802.1AR] and RFC 5280
   Section 4.1.2.5 [RFC5280]).  Such validity periods SHOULD NOT be used
   for protection of CMP messages.  Certificates for delegated CMP
   message protection (cmpCA, cmpRA, cmpKGA) MUST NOT use indefinite
   expiration date.

3.3.  Replace Section 5.1.3.4 - Multiple Protection

   Section 5.1.3.4 of RFC 4210 [RFC4210] describes the nested message.
   This document opens the usage of nested messages also for batch
   transport of PKI messages between different PKI management entities.

   Replace the text of the section with the following text.

   In cases where an end entity sends a protected PKI message to an RA,
   the RA MAY forward that message to a CA, adding its own protection
   (which MAY be a MAC or a signature, depending on the information and
   certificates shared between the RA and the CA).  There are different
   use cases for such multi protected messages.

   o  The RA confirms the validation and authorization of a message and
      forwards the original message unchanged.

   o  The RA collects several messages and forwards them in a batch.
      This can for instance be used to bridge an off-line connection
      between two PKI management entities.  In communication to the CA
      request messages and in communication from the CA response or
      announcement messages will be collected in such batch.

   o  The RA modifies the message(s) in some way (e.g., add or modify
      particular field values or add new extensions) before forwarding
      them, then it MAY create its own desired PKIBody.  In case the
      changes made by the RA to PKIMessage breaks the POP, the RA MUST
      either set the POP RAVerified or include the original PKIMessage
      from the EE in the generalInfo field of PKIHeader of the nested
      message (to force the CA to check POP on the original message).
      The infoType to be used in this situation is {id-it 15} (see
      Section 5.3.19 for the value of id-it) and the infoValue is
      PKIMessages (contents MUST be in the same order as the requests in
      PKIBody).  For simplicity reasons, if batching is used in
      combination with inclusion of the original PKIMessage in the
      generalInfo field, all messages in the batch MUST be of the same
      type (e.g., ir).

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   These use cases are accomplished by nesting the messages sent by the
   PKI entity within a new PKI message.  The structure used is as
   follows.

   NestedMessageContent ::= PKIMessages

   (The use of PKIMessages, a SEQUENCE OF PKIMessage, lets the RA batch
   the requests of several EEs in a single new message.)

3.4.  Replace Section 5.2.2. - Encrypted Values

   Section 5.2.2 of RFC 4210 [RFC4210] describes the usage of
   EncryptedValue to transport encrypted data.  This document extends
   the encryption of data to preferably use EnvelopedData.

   Replace the text of the section with the following text.

   Where encrypted data (restricted, in this specification, to be either
   private keys, certificates, or passwords) are sent in PKI messages,
   the EncryptedKey data structure is used.

   EncryptedKey ::= CHOICE {
      encryptedValue        EncryptedValue, -- deprecated
      envelopedData     [0] EnvelopedData }

   See CRMF [RFC4211] for EncryptedKey and EncryptedValue syntax and for
   EnvelopedData syntax see CMS [RFC5652].  Using the EncryptedKey data
   structure, the choice to either use EncryptedValue (for backward
   compatibility only) or EnvelopedData is offered.  The use of the
   EncryptedValue structure has been deprecated in favor of the
   EnvelopedData structure.  Therefore, it is recommended to use
   EnvelopedData.

   The EncryptedKey data structure is used in CMP to either transport a
   private key, certificate or revocation passphrase in encrypted form.

   EnvelopedData is used as follows:

   o  Contains only one recepientInfo structure because the content is
      encrypted only for one recipient.

   o  Contains a private key in a SignedData structure as specified in
      CMS section 5 [RFC5652] signed by the Key Generation Authority.

   o  Contains a certificate or revocation passphrase directly in the
      encryptedContent field.

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   Note: When transferring a centrally generated private key in a
   certificate response message to the EE, the algorithm identifier and
   the associated public key will anyhow be transported in this response
   message.  Therefore, the private key will not be delivered in a key
   package structure as specified in [RFC5958] and [RFC6032].  But the
   wrapping of the private key in a SignedData structure that is wrapped
   in the EnvelopedData structure as specified in [RFC6032] is applied.

   The content of the EnvelopedData structure, as specified in CMS
   section 3 [RFC5652], MUST be encrypted using a newly generated
   symmetric content-encryption key.  This content-encryption key MUST
   be securely provided to the recipient using one of three key
   management techniques.

   The choice of the key management technique to be used by the sender
   depends on the credential available for the recipient:

   o  Jointly shared secret: The content-encryption key will be
      protected using the symmetric key-encryption key management
      technique, as specified in CMS section 5.2.3 [RFC5652].

   o  Recipient's certificate that contains a key usage extension
      asserting keyAgreement: The content-encryption key will be
      protected using the key agreement key management technique, as
      specified in CMS section 5.2.2 [RFC5652].

   o  Recipient's certificate that contains a key usage extension
      asserting keyEncipherment: The content-encryption key will be
      protected using the key transport key management technique, as
      specified in CMS section 5.2.1 [RFC5652].

3.5.  Update Section 5.3.4. - Certification Response

   Section 5.3.4 of RFC 4210 [RFC4210] describes the Certification
   Response.  This document updates the syntax by using the parent
   structure EncryptedKey instead of EncryptedValue as described in
   Section 3.1 above.

   Replace the ASN.1 syntax of CertifiedKeyPair and CertOrEncCert with
   the following text.

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   CertifiedKeyPair ::= SEQUENCE {
       certOrEncCert       CertOrEncCert,
       privateKey      [0] EncryptedKey        OPTIONAL,
       -- see [CRMF] for comment on encoding
       publicationInfo [1] PKIPublicationInfo  OPTIONAL
   }

   CertOrEncCert ::= CHOICE {
       certificate     [0] Certificate,
       encryptedCert   [1] EncryptedKey
   }

   Add the following paragraphs to the end of the section.

   The use of EncryptedKey is described in section 5.2.2.

3.6.  Replace Section 5.3.19.9. - Revocation Passphrase

   Section 5.3.19.9 of RFC 4210 [RFC4210] describes the provisioning of
   a revocation passphrase for authenticating a later revocation
   request.  This document updates the handling by using the parent
   structure EncryptedKey instead of EncryptedValue to transport this
   information as described in Section 3.1 above.

   Replace the text of the section with the following text.

   This MAY be used by the EE to send a passphrase to a CA/RA for the
   purpose of authenticating a later revocation request (in the case
   that the appropriate signing private key is no longer available to
   authenticate the request).  See Appendix B for further details on the
   use of this mechanism.

   GenMsg:    {id-it 12}, EncryptedKey
   GenRep:    {id-it 12}, < absent >

   The use of EncryptedKey is described in section 5.2.2.

3.7.  Update Section 5.3.22 - Polling Request and Response

   Section 5.3.22 of RFC 4210 [RFC4210] describes when and how polling
   messages are used.  This document adds the polling mechanism also to
   outstanding p10cr transactions.

   Replace all paragraphs in front of the state machine diagram with the
   following text.

   This pair of messages is intended to handle scenarios in which the
   client needs to poll the server in order to determine the status of

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   an outstanding ir, cr, p10cr, or kur transaction (i.e., when the
   "waiting" PKIStatus has been received).

   PollReqContent ::= SEQUENCE OF SEQUENCE {
       certReqId    INTEGER }

   PollRepContent ::= SEQUENCE OF SEQUENCE {
       certReqId    INTEGER,
       checkAfter   INTEGER,  -- time in seconds
       reason       PKIFreeText OPTIONAL }

   The following clauses describe when polling messages are used, and
   how they are used.  It is assumed that multiple certConf messages can
   be sent during transactions.  There will be one sent in response to
   each ip, cp, or kup that contains a CertStatus for an issued
   certificate.

   1  In response to an ip, cp, or kup message, an EE will send a
      certConf for all issued certificates and, following the ack, a
      pollReq for all pending certificates.

   2  In response to a pollReq, a CA/RA will return an ip, cp, or kup if
      one or more of the pending certificates is ready; otherwise, it
      will return a pollRep.

   3  If the EE receives a pollRep, it will wait for at least as long as
      the checkAfter value before sending another pollReq.

   4  If an ip, cp, or kup is received in response to a pollReq, then it
      will be treated in the same way as the initial response.

   Note: A p10cr message contains exactly one CertificationRequestInfo
   data structure as specified in PKCS#10 [RFC2986] but no certificate
   request number.  Therefore, the certReqId MUST be set to 0 in all
   following messages of this transaction.

3.8.  Update Appendix B - The Use of Revocation Passphrase

   Appendix B of RFC 4210 [RFC4210] describes the usage of the
   revocation passphrase.  As this document updates RFC 4210 [RFC4210]
   to utilize the parent structure EncryptedKey instead of
   EncryptedValue as described in Section 3.1 above, the description is
   updated accordingly.

   Replace the first bullet point of this section with the following
   text.

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   o  The OID and value specified in Section 5.3.19.9 of RFC 4210
      [RFC4210] MAY be sent in a GenMsg message at any time, or MAY be
      sent in the generalInfo field of the PKIHeader of any PKIMessage
      at any time.  (In particular, the EncryptedKey as described in
      section 5.2.2 may be sent in the header of the certConf message
      that confirms acceptance of certificates requested in an
      initialization request or certificate request message.)  This
      conveys a revocation passphrase chosen by the entity (i.e., for
      use of EnvelopedData this is in the decrypted bytes of
      encryptedContent field and for use of EncryptedValue this is in
      the decrypted bytes of the encValue field) to the relevant CA/RA;
      furthermore, the transfer is accomplished with appropriate
      confidentiality characteristics.

   Replace the third bullet point of this section with the following
   text.

   o  When using EnvelopedData the unprotectedAttrs and when using
      EncryptedValue the valueHint field MAY contain a key identifier
      (chosen by the entity, along with the passphrase itself) to assist
      in later retrieval of the correct passphrase (e.g., when the
      revocation request is constructed by the entity and received by
      the CA/RA).

   < TBD: The attribute structure containing the key identifier in the
   unprotectedAttr field could either be pkcs-9-at-friendlyName or pkcs-
   9-at-localKeyId as specified in RFC 2985 section 5.5 [RFC2985].  Are
   there preferences for either one? >

3.9.  Update Appendix C - Request Message Behavioral Clarifications

   Appendix C of RFC 4210 [RFC4210] provides clarifications to the
   request message behavior.  As this document updates RFC 4210
   [RFC4210] to utilize the parent structure EncryptedKey instead of
   EncryptedValue as described in Section 3.1 above, the description is
   updated accordingly.

   Replace the note coming after the ASN.1 syntax of POPOPrivKey of this
   section with the following text.

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   -- **********
   -- *  the type of "thisMessage" is given as BIT STRING in RFC 4211
   -- *  [RFC4211]; it should be "EncryptedKey" (in accordance with
   -- *  Section 5.2.2 of this specification). Therefore, this document
   -- *  makes the behavioral clarification of specifying that the
   -- *  contents of "thisMessage" MUST be encoded either as
   -- *  "EnvelopedData" or "EncryptedValue" (only for backward
   -- *  compatibility) and then wrapped in a BIT STRING.  This allows
   -- *  the necessary conveyance and protection of the private key
   -- *  while maintaining bits-on-the-wire compatibility with RFC 4211
   -- *  [RFC4211].
   -- **********

3.10.  Update Appendix D.4. - Initial Registration/Certification (Basic
       Authenticated Scheme)

   Appendix D.4 of RFC 4210 [RFC4210] provides the initial registration/
   certification scheme.  This scheme shall continue to use
   EncryptedValue for backward compatibility reasons.

   Replace the comment after the privateKey field of
   crc[1].certifiedKeyPair in the syntax of the Initialization Response
   message with the following text.

   -- see Appendix C, Request Message Behavioral Clarifications
   -- for backward compatibility reasons, use EncryptedValue

4.  IANA Considerations

   < TBD: Add any IANA considerations >

5.  Security Considerations

   No changes are made to the existing security considerations of
   RFC 4210 [RFC4210].

6.  Acknowledgements

   Special thank goes to Jim Schaad for his guidance and the inspiration
   on structuring and writing this document I got from [RFC6402] that
   updates CMC.

   I also like to thank all reviewers of this document for their
   valuable feedback.

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7.  References

7.1.  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/info/rfc2119>.

   [RFC2985]  Nystrom, M. and B. Kaliski, "PKCS #9: Selected Object
              Classes and Attribute Types Version 2.0", RFC 2985,
              DOI 10.17487/RFC2985, November 2000,
              <https://www.rfc-editor.org/info/rfc2985>.

   [RFC2986]  Nystrom, M. and B. Kaliski, "PKCS #10: Certification
              Request Syntax Specification Version 1.7", RFC 2986,
              DOI 10.17487/RFC2986, November 2000,
              <https://www.rfc-editor.org/info/rfc2986>.

   [RFC4210]  Adams, C., Farrell, S., Kause, T., and T. Mononen,
              "Internet X.509 Public Key Infrastructure Certificate
              Management Protocol (CMP)", RFC 4210,
              DOI 10.17487/RFC4210, September 2005,
              <https://www.rfc-editor.org/info/rfc4210>.

   [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/info/rfc4211>.

   [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>.

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

   [RFC6402]  Schaad, J., "Certificate Management over CMS (CMC)
              Updates", RFC 6402, DOI 10.17487/RFC6402, November 2011,
              <https://www.rfc-editor.org/info/rfc6402>.

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7.2.  Informative References

   [I-D.ietf-lamps-lightweight-cmp-profile]
              Brockhaus, H., Fries, S., and D. Oheimb, "Lightweight CMP
              Profile", draft-ietf-lamps-lightweight-cmp-profile-00
              (work in progress), February 2020.

   [RFC5958]  Turner, S., "Asymmetric Key Packages", RFC 5958,
              DOI 10.17487/RFC5958, August 2010,
              <https://www.rfc-editor.org/info/rfc5958>.

   [RFC6032]  Turner, S. and R. Housley, "Cryptographic Message Syntax
              (CMS) Encrypted Key Package Content Type", RFC 6032,
              DOI 10.17487/RFC6032, December 2010,
              <https://www.rfc-editor.org/info/rfc6032>.

Appendix A.  ASN.1 Modules

   Changes to the following parts are needed

   o  Import from PKCS-9

   friendlyName, localKeyId
       FROM PKCS-9 {iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
                    pkcs-9(9) modules(0) pkcs-9(1)}

   < TBD: Either friendlyName or localKeyId need to be imported here. >

   o  Import from PKIKXCRMF-2005

   CertTemplate, PKIPublicationInfo, EncryptedKey, CertId,
   CertReqMessages
       FROM PKIXCRMF-2005 {iso(1) identified-organization(3)
       dod(6) internet(1) security(5) mechanisms(5) pkix(7)
       id-mod(0) id-mod-crmf2005(36)}

   o  In CertifiedKeyPair, CertOrEncCert and id-it-revPassphrase

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   CertifiedKeyPair ::= SEQUENCE {
       certOrEncCert       CertOrEncCert,
       privateKey      [0] EncryptedKey        OPTIONAL,
       -- see [CRMF] for comment on encoding
       publicationInfo [1] PKIPublicationInfo  OPTIONAL
   }

   CertOrEncCert ::= CHOICE {
       certificate     [0] CMPCertificate,
       encryptedCert   [1] EncryptedKey
   }

   --   id-it-revPassphrase    OBJECT IDENTIFIER ::= {id-it 12}
   --      RevPassphraseValue      ::= EncryptedKey

   --
   -- Extended Key Usage extension for PKI entities used in
   -- CMP operations
   --

   id-kp-cmpCA OBJECT IDENTIFIER ::= { id-kp 27 }
   id-kp-cmpRA OBJECT IDENTIFIER ::= { id-kp 28 }
   id-kp-cmpKGA OBJECT IDENTIFIER ::= { id-kp ... }

   < TBD: id-kp-cmpKGA to be defined. >

   < TBD: If needed the complete ASN.1 Module from RFC 4210 section
   needs to be copied here. >

Author's Address

   Hendrik Brockhaus
   Siemens AG
   Otto-Hahn-Ring 6
   Munich  81739
   Germany

   Email: hendrik.brockhaus@siemens.com
   URI:   http://www.siemens.com/

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