X.509 Certificate Extended Key Usage (EKU) for Automation
draft-ietf-lamps-automation-keyusages-06

LAMPS Working Group                                         H. Brockhaus
Internet-Draft                                                   Siemens
Intended status: Standards Track                            D. Goltzsche
Expires: 28 September 2025                              Siemens Mobility
                                                           27 March 2025

       X.509 Certificate Extended Key Usage (EKU) for Automation
                draft-ietf-lamps-automation-keyusages-06

Abstract

   RFC 5280 defines the Extended Key Usage (EKU) extension and several
   extended key purposes (KeyPurposeIds) for use with that extension in
   X.509 certificates.  This document defines KeyPurposeIds for general-
   purpose and trust anchor configuration files, for software and
   firmware update packages, and for safety-critical communication to be
   included in the EKU extension of X.509 v3 public key certificates.

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 28 September 2025.

Copyright Notice

   Copyright (c) 2025 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Brockhaus & Goltzsche   Expires 28 September 2025               [Page 1]
Internet-Draft             EKU for Automation                 March 2025

   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
     1.1.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Conventions and Definitions . . . . . . . . . . . . . . . . .   5
   3.  Extended Key Purpose for Automation . . . . . . . . . . . . .   5
   4.  Including the Extended Key Purpose in Certificates  . . . . .   6
   5.  Implications for a Certification Authority  . . . . . . . . .   7
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   7.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .   8
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   9
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   9
     10.2.  Informative References . . . . . . . . . . . . . . . . .  10
   Appendix A.  ASN.1 Module . . . . . . . . . . . . . . . . . . . .  12
   Appendix B.  History of Changes . . . . . . . . . . . . . . . . .  12
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   KeyPurposeIds added to the certificate's extended key usage extension
   as defined in [RFC5280] are meant to express intent as to the purpose
   of the named usage, for humans and for complying libraries.  In
   addition, the IANA registry "SMI Security for PKIX Extended Key
   Purpose" [RFC7299] contains additional KeyPurposeIds.  The use of the
   anyExtendedKeyUsage KeyPurposeId, as defined in Section 4.2.1.12 of
   [RFC5280], is generally considered a poor practice.

   This document defines KeyPurposeIds for certificates that are used
   for the following purposes, among others:

   *  Validating signatures of general-purpose software configuration
      files.

   *  Validating signatures of trust anchor configuration files.

   *  Validating signatures of software and firmware update packages.

Brockhaus & Goltzsche   Expires 28 September 2025               [Page 2]
Internet-Draft             EKU for Automation                 March 2025

   *  Authenticating communication endpoints authorized for safety-
      critical communication.

   If the purpose of the issued certificates is not restricted, i.e.,
   the type of operations for which a public key contained in the
   certificate can be used in unintended ways, increasing the risk of
   cross-application attacks.  Failure to ensure proper segregation of
   duties means that an application or system that generates the public/
   private keys and applies for a certificate to the operator
   certification authority could obtain a certificate that can be
   misused for tasks that this application or system is not entitled to
   perform.  For example, management of trust anchors is a particularly
   critical task.  A device could potentially accept a trust anchor
   configuration file signed by a service that uses a certificate with
   no EKU or with the KeyPurposeId id-kp-codeSigning (Section 4.2.1.12
   of [RFC5280]) or id-kp-documentSigning [RFC9336].  A device should
   only accept trust anchor configuration files if the file is verified
   with a certificate that has been explicitly issued for this purpose.

   The KeyPurposeId id-kp-serverAuth (Section 4.2.1.12 of [RFC5280]) can
   be used to identify that the certificate is for a TLS WWW server, and
   the KeyPurposeId id-kp-clientAuth (Section 4.2.1.12 of [RFC5280]) can
   be used to identify that the certificate is for a TLS WWW client.
   However, there are currently no KeyPurposeIds for usage with X.509
   certificates for safety-critical communication.

   This document addresses the above problems by defining keyPurposeIds
   for the EKU extension of X.509 public key certificates.  These
   certificates are either used for signing files (general-purpose
   configuration and trust anchor configuration files, software and
   firmware update packages) or are used for safety-critical
   communication.

   Vendor-defined KeyPurposeIds used within a PKI governed by the vendor
   or a group of vendors typically do not pose interoperability
   concerns, as non-critical extensions can be safely ignored if
   unrecognized.  However, using KeyPurposeIds outside of their intended
   vendor-controlled environment or in ExtendedKeyUsage extensions that
   have been marked critical can lead to interoperability issues.
   Therefore, it is advisable not to rely on vendor-defined
   KeyPurposeIds.  Instead, this specification defines standard
   KeyPurposeIds to ensure interoperability across various vendors and
   industries.

Brockhaus & Goltzsche   Expires 28 September 2025               [Page 3]
Internet-Draft             EKU for Automation                 March 2025

   This specification focuses on use in industrial automation and rail
   automation.  The definitions are intentionally broad to also allow
   use of the KeyPurposeIds in other deployments.  The context in which
   the KeyPurposeIds defined in this document are used is out of scope
   for this document.  The details for each deployment needs to be
   described in technical standards and certificate policies.

1.1.  Use Cases

   Automation hardware and software products will become more safe and
   secure by fulfilling mandatory, generic system requirements related
   to cyber security driven by federal offices like the European Union
   Cyber Resilience Act [EU-CRA] governed by the European Commission and
   the High Representative of the Union for Foreign Affairs and Security
   Policy.  Automation products connected to the Internet would bear the
   so called CE marking [CE-marking] to indicate they comply.  Such
   regulation was announced in the 2020 EU Cybersecurity Strategy
   [EU-STRATEGY], and complements other legislation in this area,
   specifically the NIS2 Framework, Directive on measures for a high
   common level of cybersecurity across the Union [NIS2]. 2020 EU
   Cybersecurity Strategy suggests to implement and extend international
   standards such as the Security for industrial automation and control
   systems - Part 4-2: Technical security requirements for IACS
   components [IEC.62443-4-2] (IACS refers to industrial automation and
   control system) and the Industrial communication networks - Network
   and system security - Part 3-3: System security requirements and
   security levels [IEC.62443-3-3].  Automation hardware and software
   products of diverse vendors that are connected on automation networks
   and the Internet can be used to build common automation solutions.
   Standardized attributes would allow transparency of security
   properties and interoperability for vendors in context of software
   and firmware updates, general-purpose configuration, trust anchor
   configuration, and safety communication.

   A concrete example for Automation is a Rail Automation system.  The
   Europe's Rail Joint Undertaking System Pillar [ERJU] deliver a
   unified operational concept and a functional, safe, and secure system
   architecture with system requirements for Rail Automation.  The
   deliverables include due consideration of cyber security aspects
   based on the IEC 62443 series of standards, focused on the European
   railway network to which Directive 2016/797 - Interoperability of the
   rail system within the EU [Directive-2016_797] applies.

Brockhaus & Goltzsche   Expires 28 September 2025               [Page 4]
Internet-Draft             EKU for Automation                 March 2025

2.  Conventions and Definitions

   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.

   This document uses terms defined in [RFC5280].  X.509 certificate
   extensions are defined using ASN.1 [X.680] and [X.690].

   The term 'safety-critical communication' refers to communication that
   could, under certain conditions, lead to a state in which human life,
   health, property, or the environment is endangered.  For the
   definition of 'safety' see [NIST_Glossary] and [ISO.IEC.IEEE_12207].

3.  Extended Key Purpose for Automation

   This specification defines the KeyPurposeIds id-kp-configSigning, id-
   kp-trustAnchorConfigSigning, id-kp-updatePackageSigning, and id-kp-
   safetyCommunication and uses these, respectively, for: signing
   general-purpose configuration files or trust anchor configuration
   files, signing software or firmware update packages, or
   authenticating communication peers for safety-critical communication.
   As described in Section 4.2.1.12 of [RFC5280], "[i]f the [extended
   key usage] extension is present, then the certificate MUST only be
   used for one of the purposes indicated" and "[i]f multiple [key]
   purposes are indicated the application need not recognize all
   purposes indicated, as long as the intended purpose is present".

   None of the KeyPurposeIds specified in this document are
   intrinsically mutually exclusive.  Instead, the acceptable
   combinations of those KeyPurposeIds with others specified in this
   document and with other KeyPurposeIds specified elsewhere are left to
   the technical standards of the respective application and the
   certificate policy of the respective PKI.  For example, a technical
   standard may specify: 'Different keys and certificates MUST be used
   for safety communication and for trust anchor updates, and a relying
   party MUST ignore the KeyPurposeId id-kp-trustAnchorConfigSigning if
   id-kp-safetyCommunication is one of the specified key purposes in a
   certificate.'  The certificate policy for example may specify: 'The
   id-kp-safetyCommunication KeyPuposeId SHOULD NOT be included in an
   issued certificate together with the KeyPurposeId id-kp-
   trustAnchorConfigSigning.'  Technical standards and certificate
   policies of different applications may specify other rules.  Further
   considerations on prohibiting combinations of KeyPurposeIds is
   described in the Security Considerations section of this document.

Brockhaus & Goltzsche   Expires 28 September 2025               [Page 5]
Internet-Draft             EKU for Automation                 March 2025

   Systems or applications that verify the signature of a general-
   purpose configuration file or trust anchor configuration file, the
   signature of a software or firmware update package, or the
   authentication of a communication peer for safety-critical
   communication SHOULD require that corresponding KeyPurposeIds be
   specified by the EKU extension.  If the certificate requester knows
   the certificate users are mandated to use these KeyPurposeIds, it
   MUST enforce their inclusion.  Additionally, such a certificate
   requester MUST ensure that the KeyUsage extension be set to
   digitalSignature for signature verification, to keyEncipherment for
   public key encryption, and keyAgreement for key agreement.

4.  Including the Extended Key Purpose in Certificates

   [RFC5280] specifies the EKU X.509 certificate extension for use on
   end entity certificates.  The extension indicates one or more
   purposes for which the certified public key is valid.  The EKU
   extension can be used in conjunction with the Key Usage (KU)
   extension, which indicates the set of basic cryptographic operations
   for which the certified key may be used.  The EKU extension syntax is
   repeated here for convenience:

      ExtKeyUsageSyntax  ::=  SEQUENCE SIZE (1..MAX) OF KeyPurposeId

      KeyPurposeId  ::=  OBJECT IDENTIFIER

   As described in [RFC5280], the EKU extension may, at the option of
   the certificate issuer, be either critical or non-critical.  The
   inclusion of KeyPurposeIds id-kp-configSigning, id-kp-
   trustAnchorConfigSigning, id-kp-updatePackageSigning, and id-kp-
   safetyCommunication in a certificate indicates that the public key
   encoded in the certificate has been certified for the following
   usages:

   *  id-kp-configSigning

      A public key contained in a certificate containing the
      KeyPurposeId id-kp-configSigning may be used for verifying
      signatures of general-purpose configuration files of various
      formats (for example XML, YAML, or JSON).  Configuration files are
      used to configure hardware or software.

   *  id-kp-trustAnchorConfigSigning

Brockhaus & Goltzsche   Expires 28 September 2025               [Page 6]
Internet-Draft             EKU for Automation                 March 2025

      A public key contained in a certificate containing the
      KeyPurposeId id-kp-trustAnchorConfigSigning may be used for
      verifying signatures of trust anchor configuration files of
      various formats (for example XML, YAML, or JSON).  Trust anchor
      configuration files are used to add or remove trust anchors to the
      trust store of a device.

   *  id-kp-updatePackageSigning

      A public key contained in a certificate containing the
      KeyPurposeId id-kp-updatePackageSigning may be used for verifying
      signatures of software or firmware update packages.  Update
      packages are used to install software (including bootloader,
      firmware, safety-related applications, and others) on systems.

   *  id-kp-safetyCommunication

      A public key contained in a certificate containing the
      KeyPurposeId id-kp-safetyCommunication may be used to authenticate
      a communication peer for safety-critical communication based on
      TLS or other protocols.

      id-kp  OBJECT IDENTIFIER  ::=
          { iso(1) identified-organization(3) dod(6) internet(1)
            security(5) mechanisms(5) pkix(7) 3 }

      id-kp-configSigning             OBJECT IDENTIFIER ::= { id-kp 41 }
      id-kp-trustAnchorConfigSigning  OBJECT IDENTIFIER ::= { id-kp 42 }
      id-kp-updatePackageSigning      OBJECT IDENTIFIER ::= { id-kp 43 }
      id-kp-safetyCommunication       OBJECT IDENTIFIER ::= { id-kp 44 }

5.  Implications for a Certification Authority

   The procedures and practices employed by a certification authority
   MUST ensure that the correct values for the EKU extension as well as
   the KU extension are inserted in each certificate that is issued.
   The inclusion of the id-kp-configSigning, id-kp-
   trustAnchorConfigSigning, id-kp-updatePackageSigning, and id-kp-
   safetyCommunication KeyPurposeIds does not preclude the inclusion of
   other KeyPurposeIds.

Brockhaus & Goltzsche   Expires 28 September 2025               [Page 7]
Internet-Draft             EKU for Automation                 March 2025

6.  Security Considerations

   The Security Considerations of [RFC5280] are applicable to this
   document.  These extended key usage key purposes do not introduce new
   security risks but instead reduce existing security risks by
   providing the means to identify if the certificate is generated to
   verify the signature of a general-purpose or trust anchor
   configuration file, the signature of a software or firmware update
   package, or the authentication of a communication peer for safety-
   critical communication.

   To reduce the risk of specific cross-protocol attacks, the relying
   party may additionally prohibit use of specific combinations of
   KeyPurposeIds.  The procedure for allowing or disallowing
   combinations of KeyPurposeIds using excluded KeyPurposeId and
   permitted KeyPurposeId, as carried out by a relying party, is defined
   in Section 4 of [RFC9336].  The technical standards and certificate
   policies of the application should explicitly enumerate requirements
   for excluded or permitted KeyPurposeIds or their combinations.  An
   example of excluded KeyPurposeIds can be the presence of the
   anyExtendedKeyUsage KeyPurposeId.  Examples of allowed KeyPurposeIds
   combinations can be the presence of id-kp-safetyCommunication
   together with id-kp-clinetAuth or id-kp-serverAuth.

7.  Privacy Considerations

   In some security protocols, such as TLS 1.2 [RFC5246], certificates
   are exchanged in the clear.  In other security protocols, such as TLS
   1.3 [RFC8446], the certificates are encrypted.  The inclusion of the
   EKU extension can help an observer determine the purpose of the
   certificate.  In addition, if the certificate is issued by a public
   certification authority, the inclusion of an EKU extension can help
   an attacker to monitor the Certificate Transparency logs [RFC9162] to
   identify the purpose of the certificate which may reveal private
   information of the certificate subject.

8.  IANA Considerations

   IANA is requested to register the following ASN.1 [X.680] module OID
   in the "SMI Security for PKIX Module Identifier" registry
   (1.3.6.1.5.5.7.0).  This OID is defined in Appendix A.

Brockhaus & Goltzsche   Expires 28 September 2025               [Page 8]
Internet-Draft             EKU for Automation                 March 2025

             +=========+=======================+============+
             | Decimal | Description           | References |
             +=========+=======================+============+
             | TBD1    | id-mod-automation-eku | This-RFC   |
             +---------+-----------------------+------------+

                                 Table 1

   IANA is also requested to register the following OIDs in the "SMI
   Security for PKIX Extended Key Purpose" registry (1.3.6.1.5.5.7.3).
   These OIDs are defined in Section 4.

         +=========+================================+============+
         | Decimal | Description                    | References |
         +=========+================================+============+
         | 41      | id-kp-configSigning            | This-RFC   |
         +---------+--------------------------------+------------+
         | 42      | id-kp-trustAnchorConfigSigning | This-RFC   |
         +---------+--------------------------------+------------+
         | 43      | id-kp-updatePackageSigning     | This-RFC   |
         +---------+--------------------------------+------------+
         | 44      | id-kp-safetyCommunication      | This-RFC   |
         +---------+--------------------------------+------------+

                                  Table 2

9.  Acknowledgments

   We would like to thank the authors of [RFC9336] and [RFC9509] for
   their excellent template.

   We also thank all reviewers of this document for their valuable
   feedback.

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>.

   [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>.

Brockhaus & Goltzsche   Expires 28 September 2025               [Page 9]
Internet-Draft             EKU for Automation                 March 2025

   [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>.

   [X.680]    ITU-T, "Information Technology - Abstract Syntax Notation
              One (ASN.1): Specification of basic notation", ITU-T
              Recommendation X.680 , 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 , February 2021,
              <https://www.itu.int/rec/T-REC.X.690>.

10.2.  Informative References

   [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/rfc/rfc5246>.

   [RFC7299]  Housley, R., "Object Identifier Registry for the PKIX
              Working Group", RFC 7299, DOI 10.17487/RFC7299, July 2014,
              <https://www.rfc-editor.org/rfc/rfc7299>.

   [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/rfc/rfc8446>.

   [RFC9162]  Laurie, B., Messeri, E., and R. Stradling, "Certificate
              Transparency Version 2.0", RFC 9162, DOI 10.17487/RFC9162,
              December 2021, <https://www.rfc-editor.org/rfc/rfc9162>.

   [RFC9336]  Ito, T., Okubo, T., and S. Turner, "X.509 Certificate
              General-Purpose Extended Key Usage (EKU) for Document
              Signing", RFC 9336, DOI 10.17487/RFC9336, December 2022,
              <https://www.rfc-editor.org/rfc/rfc9336>.

   [RFC9509]  Reddy.K, T., Ekman, J., and D. Migault, "X.509 Certificate
              Extended Key Usage (EKU) for 5G Network Functions",
              RFC 9509, DOI 10.17487/RFC9509, March 2024,
              <https://www.rfc-editor.org/rfc/rfc9509>.

Brockhaus & Goltzsche   Expires 28 September 2025              [Page 10]
Internet-Draft             EKU for Automation                 March 2025

   [Directive-2016_797]
              European Parliament, Council of the European Union,
              "Directive 2016/797 - Interoperability of the rail system
              within the EU", May 2020,
              <https://eur-lex.europa.eu/eli/dir/2016/797/2020-05-28>.

   [ERJU]     Europe's Rail Joint Undertaking, "SP-Cybersecurity-
              SharedCybersecurityServices - Review 3 Final Draft Specs
              (V0.90)", September 2024, <https://rail-
              research.europa.eu/wp-content/uploads/2023/10/
              ERJU_SP_CyberSecurity_Review3_Files.zip>.

   [EU-CRA]   European Commission, "Proposal for a REGULATION OF THE
              EUROPEAN PARLIAMENT AND OF THE COUCIL on horizontal
              cybersecurity requirements for products with digital
              elements and amending Regulation (EU) 2019/1020",
              September 2022, <https://digital-
              strategy.ec.europa.eu/en/library/cyber-resilience-act>.

   [EU-STRATEGY]
              European Commission, "The EU's Cybersecurity Strategy for
              the Digital Decade", December 2020, <https://digital-
              strategy.ec.europa.eu/en/library/eus-cybersecurity-
              strategy-digital-decade-0>.

   [NIST_Glossary]
              NIST CSRC, "Directive (EU) 2022/2555 of the European
              Parliament and of the Council", n.d.,
              <https://csrc.nist.gov/glossary/term/safety>.

   [ISO.IEC.IEEE_12207]
              ISO/IEC/IEEE, "Systems and software engineering – Software
              life cycle processes", December 2024,
              <https://www.iso.org/standard/63712.html>.

   [NIS2]     European Commission, "Directive (EU) 2022/2555 of the
              European Parliament and of the Council", December 2024,
              <https://digital-strategy.ec.europa.eu/en/policies/
              nis2-directive>.

   [IEC.62443-4-2]
              IEC, "Security for industrial automation and control
              systems - Part 4-2: Technical security requirements for
              IACS components", IEC 62443-4-2:2019 , February 2019,
              <https://webstore.iec.ch/publication/34421>.

Brockhaus & Goltzsche   Expires 28 September 2025              [Page 11]
Internet-Draft             EKU for Automation                 March 2025

   [IEC.62443-3-3]
              IEC, "Industrial communication networks - Network and
              system security - Part 3-3: System security requirements
              and security levels", IEC 62443-3-3:2013 , August 2013,
              <https://webstore.iec.ch/publication/7033>.

   [CE-marking]
              European Commission, "CE marking", n.d., <https://single-
              market-economy.ec.europa.eu/single-market/ce-marking_en>.

Appendix A.  ASN.1 Module

   The following module adheres to ASN.1 specifications [X.680] and
   [X.690].

   <CODE BEGINS>

   Automation-EKU
     { iso(1) identified-organization(3) dod(6) internet(1)
       security(5) mechanisms(5) pkix(7) id-mod(0)
       id-mod-automation-eku (TBD1) }

   DEFINITIONS IMPLICIT TAGS ::=
   BEGIN

   -- OID Arc

   id-kp OBJECT IDENTIFIER ::=
     { iso(1) identified-organization(3) dod(6) internet(1)
       security(5) mechanisms(5) pkix(7) kp(3) }

   -- Extended Key Usage Values

   id-kp-configSigning            OBJECT IDENTIFIER ::= { id-kp 41 }
   id-kp-trustAnchorConfigSigning OBJECT IDENTIFIER ::= { id-kp 42 }
   id-kp-updatePackageSigning     OBJECT IDENTIFIER ::= { id-kp 43 }
   id-kp-safetyCommunication      OBJECT IDENTIFIER ::= { id-kp 44 }

   END

   <CODE ENDS>

Appendix B.  History of Changes

   [RFC Editor: Please remove this appendix in the release version of
   the document.]

Brockhaus & Goltzsche   Expires 28 September 2025              [Page 12]
Internet-Draft             EKU for Automation                 March 2025

   Changes from 05 -> 06:

   *  Addressed AD review comments from Mike Bishop, Gorry Fairhurst,
      Andy Newton, Mohamed Boucadair, Erik Kline, and Eric Vyncke

   Changes from 04 -> 05:

   *  Addressed SECDIR review comments from Carl Wallace

   Changes from 03 -> 04:

   *  Addressed Deb's AD review comments (see "AD Comments on draft-
      ietf-lamps-automation-keyusages")

   *  Added early allocated OIDs

   Changes from 02 -> 03:

   *  Rename id-kp-trustanchorSigning to id-kp-trustAnchorConfigSigning

   *  Rename id-kp-updateSigning to id-kp-updatePackageSigning

   *  Fixed some nits

   Changes from 01 -> 02:

   *  Updates Sections 3 and 6 addressing last call comments (see "WG
      Last Call for draft-ietf-lamps-automation-keyusages-01")

   Changes from 01 -> 02:

   *  Implemented the changes requested during WGLC

   Changes from 00 -> 01:

   *  Fixed some minor nids and wording issues

   draft-ietf-lamps-automation-keyusages version 00:

   *  Updated document and filename after WG adoption

   Changes from 00 -> 01:

   *  Updated last paragraph of Section 1 addressing WG adoption
      comments by Rich and Russ

   *  Updated name and OID of ASN.1 module

Brockhaus & Goltzsche   Expires 28 September 2025              [Page 13]
Internet-Draft             EKU for Automation                 March 2025

   draft-brockhaus-lamps-automation-keyusages version 00:

   *  Broadened the scope to general automation use case and use ERJU as
      an example.

   *  Fixed some nits reported.

   draft-brockhaus-lamps-eu-rail-keyusages version 00:

   *  Initial version of the document following best practices from RFC
      9336 and RFC 9509

Contributors

   Szofia Fazekas-Zisch
   Siemens AG Digital Industries Factory Automation
   Breslauer Str. 5
   90766 Fuerth
   Germany
   Email: szofia.fazekas-zisch@siemens.com
   URI:   https://www.siemens.com

   Baptiste Fouques
   Alstom
   Email: baptiste.fouques@alstomgroup.com

   Daniel Gutierrez Orta
   CAF Signalling
   Email: daniel.gutierrez@cafsignalling.com

   Martin Weller
   Hitachi Rail
   Email: martin.weller@urbanandmainlines.com

   Nicolas Poyet
   SNCF
   Email: nicolas.poyet@sncf.fr

Authors' Addresses

Brockhaus & Goltzsche   Expires 28 September 2025              [Page 14]
Internet-Draft             EKU for Automation                 March 2025

   Hendrik Brockhaus
   Siemens
   Werner-von-Siemens-Strasse 1
   80333 Munich
   Germany
   Email: hendrik.brockhaus@siemens.com
   URI:   https://www.siemens.com

   David Goltzsche
   Siemens Mobility
   Ackerstrasse 22
   38126 Braunschweig
   Germany
   Email: david.goltzsche@siemens.com
   URI:   https://www.mobility.siemens.com

Brockhaus & Goltzsche   Expires 28 September 2025              [Page 15]