Extensions to Automatic Certificate Management Environment for end user S/MIME certificates
draft-ietf-acme-email-smime-07

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Network Working Group                                        A. Melnikov
Internet-Draft                                                 Isode Ltd
Intended status: Informational                               May 2, 2020
Expires: November 3, 2020

Extensions to Automatic Certificate Management Environment for end user
                          S/MIME certificates
                     draft-ietf-acme-email-smime-07

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

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   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on November 3, 2020.

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   Copyright (c) 2020 IETF Trust and the persons identified as the
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   2
   3.  Use of ACME for issuing end user S/MIME certificates  . . . .   2
     3.1.  ACME challenge email  . . . . . . . . . . . . . . . . . .   3
     3.2.  ACME response email . . . . . . . . . . . . . . . . . . .   5
   4.  Open Issues . . . . . . . . . . . . . . . . . . . . . . . . .   6
   5.  Internationalization Considerations . . . . . . . . . . . . .   6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   7
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .  10
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  10

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.

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 "dns" Identifier Type that is used to verify
   that a particular entity has control over a domain or specific
   service associated with the domain.  In order to be able to issue
   end-user S/MIME certificates, ACME needs a new Identifier Type that
   proves ownership of an email address.

   This document defines a new Identifier Type "email" which corresponds
   to an (all ASCII) email address [RFC5321] or Internationalized Email
   addresses [RFC6531].  (When Internationalized Email addresses are
   used, both U-labels and A-labels [RFC5890] are allowed in the domain
   part.)  This can be used with S/MIME or other similar service that
   requires posession of a certificate tied to an email address.

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   Any identifier of type "email" in a newOrder request MUST NOT have a
   wildcard ("*") character in its value.

   A new challenge type "email-reply-00" is used with "email" Identifier
   Type, which provides proof that an ACME client has control over an
   email address: