Online Certificate Status Protocol (OCSP) Nonce Extension
draft-hsharma-lamps-ocsp-nonce-05

Internet Engineering Task Force                           H. Sharma, Ed.
Internet-Draft                                              Netskope Inc
Updates: 8954 (if approved)                              8 November 2023
Intended status: Informational                                          
Expires: 11 May 2024

       Online Certificate Status Protocol (OCSP) Nonce Extension
                   draft-hsharma-lamps-ocsp-nonce-05

Abstract

   This document updates the Nonce extension section of RFC-8954.  Nonce
   extension is a optional extension for Online Certificate Status
   Protocol (OCSP) request and response messages.  OCSP is used for
   checking the status of a certificate, and the Nonce extension is used
   to cryptographically bind an OCSP response message to a particular
   OCSP request message.  This document updates RFC 8954.

Status of This Memo

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   This Internet-Draft will expire on 11 May 2024.

Copyright Notice

   Copyright (c) 2023 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   This document is subject to BCP 78 and the IETF Trust's Legal
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   Please review these documents carefully, as they describe your rights
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  OCSP Extensions . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Nonce Extension . . . . . . . . . . . . . . . . . . . . .   3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   This document updates the usage of the Nonce extension in OCSP
   request and response messages.  This extension was previously defined
   in Section 4.4.1 of [RFC6960] and updated in [RFC8954].  [RFC6960]
   defines OCSP extensions as optional extension, and defines condition
   for different extension options.  [RFC6960] Nonce extension is
   defined as an optional extension and that provides the freedom to
   OCSP responders to ignore the Nonce extension regardless of its
   existence or value in OCSP request, whereas [RFC8954] language
   directs the OCSP responders to MUST take action based on Nonce value
   in OCSP requests.  For example it directs OCSP responder to MUST
   respond with the malformedRequest OCSPResponseStatus in case of zero
   or longer Nonce values.

   OCSP responder SHOULD be able to ignore the Nonce values (valid or
   invalid) as it is an optional extension.  Ignoring the longer Nonce
   value helps OCSP responder to achieve the better backward
   compatibility as it wont impact the existing OCSP client that has
   already been sending longer Nonce values.  This document updates the
   Nonce extension section of [RFC8954] by removing the instruction to
   OCSP responder to reject the OCSP response that violates the Nonce
   length requirment, provides an example of Nonce value and reinstate
   the backward compatibility while clearly differentiating the OCSP
   client and responder expectations.

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1.1.  Requirements Language

   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.

2.  OCSP Extensions

   The message formats for OCSP requests and responses are defined in
   [RFC6960] and Nonce extension was updated in [RFC8954].  [RFC6960]
   also defines the standard extensions for OCSP messages based on the
   extension model employed in X.509 version 3 certificates (see
   [RFC5280]).  [RFC8954] replaces this section to enforce minimum and
   maximum length for Nonce value.  This document updates the Nonce
   extension section of [RFC8954] with clearly define the behavior of
   OCSP responder and client under precondition of support of Nonce
   extension while ignoring the OCSP request with longer Nonce length of
   32 octets.  This document doesn't change the length requirement for
   Nonce value and does not change the specifications of any of the
   other standard extensions defined in [RFC6960] or [RFC8954].

2.1.  Nonce Extension

   This section updates the Section 2.1 of [RFC8954], which describes
   the OCSP Nonce extension.

   The Nonce cryptographically binds a request and a response to prevent
   replay attacks.The Nonce is included as one of the requestExtensions
   in requests; in responses, it would be included as one of the
   responseExtensions.In both the request and the response, the Nonce
   will be identified by the object identifier id-pkix-ocsp-Nonce, while
   the extnValue is the value of the Nonce.  If the Nonce extension is
   present, then the length of the Nonce MUST be at least 1 octet and
   can be up to 32 octets.

   OCSP client that supports Nonce extension MUST use the length of 32
   octets.  OCSP responder that supports the Nonce extension MUST
   support the Nonce value with minimum length of 16 octets to maximum
   length of 32 octets.  OCSP responder MAY choose to ignore Nonces that
   are less than 16 octets or violates Nonce length defined in
   [RFC8954], and MUST leave out the Nonce extension in the response.

   The value of the Nonce MUST be generated using a cryptographically
   strong pseudorandom number generator (see [RFC4086]).  The minimum
   Nonce length of 1 octet is defined to provide backward compatibility
   with older clients that follow [RFC6960].

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       id-pkix-ocsp           OBJECT IDENTIFIER ::= { id-ad-ocsp }
       id-pkix-ocsp-Nonce     OBJECT IDENTIFIER ::= { id-pkix-ocsp 2 }

   Nonce ::= OCTET STRING(SIZE(1..32))

   Raw Nonce Example:
   1FA16041C0E2D739898EC69972A4B967DFD3488148E6DA61CF3AF2DC32383383

   OCSP Nonce Octet String:
   04201FA16041C0E2D739898EC69972A4B967DFD3488148E6DA61CF3AF2DC32383383

3.  IANA Considerations

   This memo includes no request to IANA.

4.  Security Considerations

   This document should not affect the security of the Internet.

5.  References

5.1.  Normative References

   [RFC6960]  Santesson, S., Myers, M., Ankney, R., Malpani, A.,
              Galperin, S., and C. Adams, "X.509 Internet Public Key
              Infrastructure Online Certificate Status Protocol - OCSP",
              RFC 6960, DOI 10.17487/RFC6960, June 2013,
              <https://www.rfc-editor.org/info/rfc6960>.

   [RFC8954]  Sahni, M., Ed., "Online Certificate Status Protocol (OCSP)
              Nonce Extension", RFC 8954, DOI 10.17487/RFC8954, November
              2020, <https://www.rfc-editor.org/info/rfc8954>.

   [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>.

   [RFC4086]  Eastlake 3rd, D., Schiller, J., and S. Crocker,
              "Randomness Requirements for Security", BCP 106, RFC 4086,
              DOI 10.17487/RFC4086, June 2005,
              <https://www.rfc-editor.org/info/rfc4086>.

   [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>.

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   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

Author's Address

   Himanshu Sharma (editor)
   Netskope Inc
   2445 Augustine Dr 3rd floor
   Santa Clara, California 95054
   United States of America
   Email: himanshu@netskope.com
   URI:   www.netskope.com

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