Extensions to Automatic Certificate Management Environment for end-user S/MIME certificates
draft-ietf-acme-email-smime-14

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 00
• 01
• 02
• 03
• 04
• 05
• 06
• 07
• 08
• 09
• 10
• 11
• 12
• 13
• 14

Network Working Group                                        A. Melnikov
Internet-Draft                                                 Isode Ltd
Intended status: Informational                         February 15, 2021
Expires: August 19, 2021

Extensions to Automatic Certificate Management Environment for end-user
                          S/MIME certificates
                     draft-ietf-acme-email-smime-14

Abstract

   This document specifies identifiers and challenges required to enable
   the Automated Certificate Management Environment (ACME) to issue
   certificates for use by email users that want to use S/MIME.

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 August 19, 2021.

Copyright Notice

   Copyright (c) 2021 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
   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.

Melnikov                 Expires August 19, 2021                [Page 1]
Internet-Draft               ACME for S/MIME               February 2021

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   3
   3.  Use of ACME for issuing end-user S/MIME certificates  . . . .   3
     3.1.  ACME challenge email  . . . . . . . . . . . . . . . . . .   5
     3.2.  ACME response email . . . . . . . . . . . . . . . . . . .   7
     3.3.  Generating encryption only or signing only S/MIME
           certificates  . . . . . . . . . . . . . . . . . . . . . .   9
   4.  Internationalization Considerations . . . . . . . . . . . . .   9
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
     5.1.  ACME Identifier Type  . . . . . . . . . . . . . . . . . .  10
     5.2.  ACME Challenge Type . . . . . . . . . . . . . . . . . . .  10
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  12
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  14
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .  15
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   ACME [RFC8555] is a mechanism for automating certificate management
   on the Internet.  It enables administrative entities to prove
   effective control over resources like domain names, and automates the
   process of generating and issuing certificates.

   This document describes an extension to ACME for use by S/MIME.
   Section 3 defines extensions for issuing end-user S/MIME [RFC8550]
   certificates.

   This document aims to support both:

   1.  A Mail User Agent (MUA) which has built-in ACME client which is
       aware of the extension described in this document.  (We will call
       such MUAs "ACME-email-aware".)  Such MUA can present nice User
       Interface to the user and automate certificate issuance.

   2.  A MUA which is not ACME aware, with a separate ACME client
       implemented in a command line tool or as a part of a website.
       While S/MIME certificate issuance is not going to be as painless
       as in the case of the ACME-email-aware MUA, the extra burden on a
       user is going to be minimal.

Melnikov                 Expires August 19, 2021                [Page 2]
Internet-Draft               ACME for S/MIME               February 2021

2.  Conventions Used in This Document

   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].

3.  Use of ACME for issuing end-user S/MIME certificates

   ACME [RFC8555] defines a "dns" Identifier Type that is used to verify