RFC 5967 INFORMATIONAL MEDIA TYPES · CERTIFICATES

The application/pkcs10 Media Type

The media type label for sending a PKCS #10 certificate request, carried over from an old S/MIME RFC.

On rfc-editor.org ↗
PUBLISHED
August 2010
AUTHORS
S. Turner
STREAM
IETF
BUILDS ON
RFC 2986 — PKCS #10
MEDIA TYPE
application/pkcs10
FILE EXTENSION
.p10
ENCODING
binary (DER preferred, base64 for 7-bit transports)
DOI
10.17487/RFC5967

RFC text

Contents
Original text · RFC Editor View on rfc-editor.org ↗
Internet Engineering Task Force (IETF)                         S. Turner
Request for Comments: 5967                                          IECA
Updates: 2986                                                August 2010
Category: Informational
ISSN: 2070-1721


                   The application/pkcs10 Media Type

Abstract

   This document specifies a media type used to carry PKCS #10
   certification requests as defined in RFC 2986.  It carries over the
   original specification from RFC 2311, which recently has been moved
   to Historic status, and properly links it to RFC 2986.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc5967.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
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   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

1.  Introduction

   [RFC2311] first defined the application/pkcs10 media type.  When
   [RFC2633] was published, the application/pkcs10 section was dropped,
   but for some reason the text was not incorporated into the PKCS #10
   document [RFC2986].  [RFC2311] was moved to Historic status by
   [RFC5751].  To ensure the IANA media type registration points to a
   non-Historic document, this document updates [RFC2986] with the
   definition of the application/pkcs10 media type and an IANA
   registration based on [RFC4288].

   The text for Section 2 is adapted from Section 3.7 of [RFC2311].

1.1.  Requirements 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 [RFC2119].

2.  Creating a Certification Request

   A typical application that allows a user to generate cryptographic
   information has to submit that information to a Certification
   Authority (CA), who transforms it into a certificate.  PKCS #10
   [RFC2986] describes a syntax for certification requests.

   The details of certification requests and the process of obtaining a
   certificate are beyond the scope of this memo.  Instead, only the
   format of data used in application/pkcs10 is defined.

2.1.  Format of the application/pkcs10 Body

   PKCS #10 defines the ASN.1 type CertificationRequest for use in
   submitting a certification request.  For transfer to a CA, this
   abstract syntax needs to be encoded and identified in a unique
   manner.  When the media type application/pkcs10 is used, the body
   MUST be a CertificationRequest.

   A robust application SHOULD output Distinguished Encoding Rules
   (DER), but allow Basic Encoding Rules (BER) or DER on input.

   Data produced by BER or DER is 8-bit, but some transports are limited
   to 7-bit data.  In such cases, a suitable 7-bit transfer encoding
   MUST be applied; in MIME-compatible transports, the base64 encoding
   [RFC4648] SHOULD be used with application/pkcs10, although any 7-bit
   transfer encoding may work.

2.2.  Sending and Receiving an application/pkcs10 Body Part

   For sending a certificate-signing request, the application/pkcs10
   message format MUST be used to convey a PKCS #10 certificate-signing
   request.  Note that for sending certificates and Certificate
   Revocation Lists (CRLs) without any signed content, the
   application/pkcs7-mime message format MUST be used to convey a
   degenerate PKCS #7 signedData "certs-only" message [RFC5751].

   To send an application/pkcs10 body, the application generates the
   cryptographic information for the user.  The details of the
   cryptographic information are beyond the scope of this memo.

   Step 1. The cryptographic information is placed within a PKCS #10
           CertificationRequest.

   Step 2. The CertificationRequest is encoded according to BER or DER
           (preferred, DER).

   Step 3. As a typical step, the encoded CertificationRequest is also
           base64 encoded so that it is 7-bit data suitable for transfer
           in ESMTP.  This then becomes the body of an
           application/pkcs10 body part.

   The result might look like this:

      Content-Type: application/pkcs10; name=smime.p10
      Content-Transfer-Encoding: base64
      Content-Disposition: attachment; filename=smime.p10

      rfvbnj756tbBghyHhHUujhJhjH77n8HHGT9HG4VQpfyF467GhIGfHfYT6
      7n8HHGghyHhHUujhJh4VQpfyF467GhIGfHfYGTrfvbnjT6jH7756tbB9H
      f8HHGTrfvhJhjH776tbB9HG4VQbnj7567GhIGfHfYT6ghyHhHUujpfyF4
      0GhIGfHfQbnj756YT64V
   A typical application only needs to send a certification request.  It
   is a Certification Authority that has to receive and process the
   request.  The steps for recovering the CertificationRequest from the
   message are straightforward but are not presented here.  The
   procedures for processing the certification request are beyond the
   scope of this document.

3.  IANA Considerations

   IANA has updated the registration for the application/pkcs10 media
   subtype in the Application Media Types registry using the filled-in
   template from BCP 13 [RFC4288] given below.

3.1.  Registration of Media Subtype application/pkcs10

   The media subtype for a PKCS #10 certification request is
   application/pkcs10.

      Type name: application

      Subtype name: pkcs10

      Required parameters: None

      Optional parameters: None

      Encoding considerations: binary; see Section 2.

      Security considerations:

         Clients use a certification request to request that a
         Certification Authority certify a public key.  The
         certification request is digitally signed.  Also, see
         Section 6.

      Interoperability considerations: See Section 2.

      Published specification: This specification.

      Applications which use this media type:

         Applications that support PKCS #10 certification requests
         [RFC2986].

      Additional information:

         Magic number(s): None
         File extension(s): .p10
         Macintosh File Type Code(s):

      Person & email address to contact for further information:
        Sean Turner <turners@ieca.com>

      Restrictions on usage: none

      Author: Sean Turner <turners@ieca.com>

      Intended usage: COMMON

      Change controller: The IESG

4.  Security Considerations

   The security considerations of [RFC2986] and [RFC5751] apply; no new
   security considerations are introduced by this document.

5.  Acknowledgements

   I wish to thank the authors of RFC 2311, Steve Dusse, Paul Hoffman,
   Blake Ramsdell, Laurence Lundblade, and Lisa Repka.

   I would also like to thank Bjoern Hoehrmann for his review of the
   media subtype application.

6.  References

6.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2986]  Nystrom, M. and B. Kaliski, "PKCS #10: Certification
              Request Syntax Specification Version 1.7", RFC 2986,
              November 2000.

   [RFC4288]  Freed, N. and J. Klensin, "Media Type Specifications and
              Registration Procedures", BCP 13, RFC 4288, December 2005.

   [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
              Encodings", RFC 4648, October 2006.

   [RFC5751]  Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet
              Mail Extensions (S/MIME) Version 3.2 Message
              Specification", RFC 5751, January 2010.

   [X.690]    ITU-T Recommendation X.690 (2002) | ISO/IEC 8825-1:2002.
              Information Technology - ASN.1 encoding rules:
              Specification of Basic Encoding Rules (BER), Canonical
              Encoding Rules (CER) and Distinguished Encoding Rules
              (DER).

6.2.  Informative References

   [RFC2311]  Dusse, S., Hoffman, P., Ramsdell, B., Lundblade, L., and
              L. Repka, "S/MIME Version 2 Message Specification", RFC
              2311, March 1998.

   [RFC2633]  Ramsdell, B., Ed., "S/MIME Version 3 Message
              Specification", RFC 2633, June 1999.

Author's Address

   Sean Turner
   IECA, Inc.
   3057 Nutley Street, Suite 106
   Fairfax, VA 22031
   USA

   EMail: turners@ieca.com

AI ELI5

On this page
PROBLEMThe application/pkcs10 media type was defined in RFC 2311, which was moved to Historic, so the IANA registration pointed at a Historic document and the PKCS #10 specification did not describe the type.
MECHANISMRFC 5967 carries the definition over: the body MUST be a PKCS #10 CertificationRequest, preferably DER-encoded and base64-encoded for 7-bit transports, and it redoes the IANA registration.
WHY IT MATTERSThe registration now points to a non-Historic document, and RFC 5967 formally updates RFC 2986.

§1Why This Document Exists

RFC 2311 first defined the application/pkcs10 media type. When RFC 2633 was published, that section was dropped, but the text was not added to the PKCS #10 document, RFC 2986. Later, RFC 5751 moved RFC 2311 to Historic status.

To make sure the IANA media type registration points at a non-Historic document, RFC 5967 updates RFC 2986 with the definition of the type and a new IANA registration based on RFC 4288. The text of its Section 2 is adapted from Section 3.7 of RFC 2311.

An old rulebook that described the label got retired, and the new rulebook forgot to copy it. This document puts the label description back where it belongs.

§2.1The Body Format

PKCS #10 defines the ASN.1 type CertificationRequest, used to ask a Certification Authority (CA) for a certificate. When the media type application/pkcs10 is used, the body MUST be a CertificationRequest.

A robust application SHOULD output Distinguished Encoding Rules (DER) but accept Basic Encoding Rules (BER) or DER on input. BER and DER produce 8-bit data, so where a transport is limited to 7-bit data a suitable 7-bit transfer encoding MUST be applied. In MIME-compatible transports, base64 SHOULD be used.

The envelope must hold a properly filled-in request form. Write it in the tidy, standard way, and if the post office only handles plain letters, turn it into plain letters first.

§2.2Sending a Request

To send a certificate-signing request, the application/pkcs10 message format MUST be used. Certificates and CRLs without signed content are different: they use application/pkcs7-mime instead.

The sender places the cryptographic information in a CertificationRequest, encodes it as BER or DER (DER preferred), and typically base64-encodes it so it is 7-bit data suitable for ESMTP. The result becomes the body of an application/pkcs10 body part. Recovering and processing the request on the CA side is left out of scope.

You fill in the form, fold it the standard way, turn it into plain letters, and put it in an envelope marked with the right label.

EXAMPLE FROM RFC 5967 SECTION 2.2
An application/pkcs10 body part
Content-Type: application/pkcs10; name=smime.p10
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename=smime.p10

rfvbnj756tbBghyHhHUujhJhjH77n8HHGT9HG4VQpfyF467GhIGfHfYT6
7n8HHGghyHhHUujhJh4VQpfyF467GhIGfHfYGTrfvbnjT6jH7756tbB9H
f8HHGTrfvhJhjH776tbB9HG4VQbnj7567GhIGfHfYT6ghyHhHUujpfyF4
0GhIGfHfQbnj756YT64V

§3The IANA Registration

IANA updated the registration of the pkcs10 subtype in the Application Media Types registry, using the template from BCP 13. The type name is application, there are no required or optional parameters, and the encoding is binary.

The registration lists .p10 as the file extension, no magic number, an intended usage of COMMON, and the IESG as change controller.

The official list of envelope labels now has this label filled in properly, with the file ending .p10.

§4Security Considerations

The security considerations of RFC 2986 and RFC 5751 apply. RFC 5967 introduces no new ones. The registration notes that clients use a certification request to ask a CA to certify a public key, and that the request is digitally signed.

Nothing new to worry about: the request is signed, and the older rules still apply.

§6References