Using a DNS SRV Record to Locate an X.509 Certificate Store
draft-bhjl-x509-srv-03

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Last updated 2017-01-16
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Network Working Group                                        B. Haberman
Internet-Draft                                                   JHU APL
Intended status: Standards Track                               J. Levine
Expires: July 20, 2017                              Taughannock Networks
                                                        January 16, 2017

      Using a DNS SRV Record to Locate an X.509 Certificate Store
                         draft-bhjl-x509-srv-03

Abstract

   This document describes a method to allow parties to locate X.509
   certificate stores with Domain Name System Service records in order
   to retrieve certificates and certificate revocation lists.  The
   primary purpose of such retrievals is to facilitate the association
   of X.509 and PGP public keys with e-mail addresses to allow for
   encrypted e-mail exchanges.

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   This Internet-Draft will expire on July 20, 2017.

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   Copyright (c) 2017 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
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Haberman & Levine         Expires July 20, 2017                 [Page 1]
Internet-Draft            Cert Store SRV Record             January 2017

   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Service Record Format . . . . . . . . . . . . . . . . . . . .   2
   3.  Certificate Store Queries . . . . . . . . . . . . . . . . . .   3
   4.  Name Matching . . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Certificate Validation  . . . . . . . . . . . . . . . . . . .   4
   6.  Certificate use and cacheing  . . . . . . . . . . . . . . . .   5
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
     8.1.  Certificates service  . . . . . . . . . . . . . . . . . .   6
     8.2.  Smimeca service . . . . . . . . . . . . . . . . . . . . .   6
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   10. Normative References  . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   X.509 and PGP public keys can be used to encrypt or sign e-mail
   messages.  In order to verify a sender's signature or encrypt an
   e-mail, the e-mail client needs to locate the appropriate public key.
   The X.509-based Public Key Infrastructure (PKI) [RFC5280] provides
   the necessary services to allow for the retrieval of certificates and
   certificate revocation lists, but lacks the discovery mechanism
   needed to associate e-mail domains with specific PKI servers.

   This document specifies an approach that uses a Domain Name System
   (DNS) Service Record (SRV) that allows mail service providers to
   advertise the X.509 or PGP certificate store [RFC4387] that contains
   certificates and certificate revocation lists for their e-mail users.
   Additionally, this document specifies the appropriate query strings
   to use when accessing the certificate store.

   The capitalized 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.  Service Record Format

   The general format of a DNS SRV record is documented in [RFC2782] as:

        _Service._Proto.Name TTL Class SRV Priority Weight Port Target
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