Network Working Group A. Melnikov Internet-Draft Isode Ltd Intended status: Standards Track October 14, 2013 Expires: April 17, 2014 MSA-to-MDA S/MIME signing & encryption draft-melnikov-smime-msa-to-mda-00 Abstract This document specifies how S/MIME signing and encryption can be applied between a Message Submission Agent (MSA) and a Message Delivery Agent (MDA) or between 2 Message Transfer Agents (MTA). 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 http://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 April 17, 2014. Copyright Notice Copyright (c) 2013 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 (http://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 April 17, 2014 [Page 1] Internet-Draft MSA-to-MDA S/MIME October 2013 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions Used in This Document . . . . . . . . . . . . . . 2 3. MSA-to-MDA S/MIME signing & encryption . . . . . . . . . . . 2 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 2 5. Security Considerations . . . . . . . . . . . . . . . . . . . 3 6. Normative References . . . . . . . . . . . . . . . . . . . . 3 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 3 1. Introduction [RFC3183] specifies Domain Security Services using S/MIME. The motivation provided there remains largely the same. This document specifies a simplified variant of Domain Security Services to be used between an MSA/MTA and an MTA/MDA. 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. MSA-to-MDA S/MIME signing & encryption An MSA/MTA wishing to sign or encrypt an email message on bahalf of a domain ("originating S/MIME MSA" or "originating S/MIME MTA") follows rules specified in [RFC3183], except as specified in this document. Originating S/MIME MSA/MTA uses a domain signature as specified in [RFC3183]. However the rules below replace naming rules specified in Sections 3.1.1 and 4.1 of that document. The subject name of the Originating S/MIME MSA/MTA's X.509 certificate is not restricted as specified in RFC 3183. In order for a verifier to recognize a signing/encrypting certificate as the Originating S/MIME MSA/MTA's certificate, it MUST contain uniformResourceIdentifier GeneralName of the format "smtp://" in its SubjectAltName. (Here is the domain that is being served by the signing/encrypting MSA/MTA.) An rfc822Name GeneralName as specified in RFC 3183 MAY optionally be included in the SubjectAltName. [[Do we need to distinguish signing versa encryption in certificate's SubjectAltName?]] 4. IANA Considerations Melnikov Expires April 17, 2014 [Page 2] Internet-Draft MSA-to-MDA S/MIME October 2013 This document doesn't require any action from IANA. 5. Security Considerations TBD 6. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3183] Dean, T. and W. Ottaway, "Domain Security Services using S /MIME", RFC 3183, October 2001. [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, May 2008. [RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322, October 2008. [RFC5751] Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.2 Message Specification", RFC 5751, January 2010. Appendix A. Acknowledgements TBD Author's Address Alexey Melnikov Isode Ltd 5 Castle Business Village 36 Station Road Hampton, Middlesex TW12 2BX UK EMail: Alexey.Melnikov@isode.com Melnikov Expires April 17, 2014 [Page 3]