Using Secure DNS to Associate Certificates with Domain Names for S/MIME
RFC 8162
Document | Type |
RFC - Experimental
(May 2017; No errata)
Was draft-ietf-dane-smime (dane WG)
|
|
---|---|---|---|
Authors | Paul Hoffman , Jakob Schlyter | ||
Last updated | 2017-05-31 | ||
Replaces | draft-hoffman-dane-smime | ||
Stream | Internent Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Ólafur Guðmundsson | ||
Shepherd write-up | Show (last changed 2017-02-05) | ||
IESG | IESG state | RFC 8162 (Experimental) | |
Action Holders |
(None)
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||
Consensus Boilerplate | Yes | ||
Telechat date | |||
Responsible AD | Stephen Farrell | ||
Send notices to | (None) | ||
IANA | IANA review state | Version Changed - Review Needed | |
IANA action state | RFC-Ed-Ack |
Internet Engineering Task Force (IETF) P. Hoffman Request for Comments: 8162 ICANN Category: Experimental J. Schlyter ISSN: 2070-1721 Kirei AB May 2017 Using Secure DNS to Associate Certificates with Domain Names for S/MIME Abstract This document describes how to use secure DNS to associate an S/MIME user's certificate with the intended domain name, similar to the way that DNS-Based Authentication of Named Entities (DANE), RFC 6698, does for TLS. Status of This Memo This document is not an Internet Standards Track specification; it is published for examination, experimental implementation, and evaluation. This document defines an Experimental Protocol for the Internet community. 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 7841. 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/rfc8162. Copyright Notice 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 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. Hoffman & Schlyter Experimental [Page 1] RFC 8162 DNS-Based Authentication for S/MIME May 2017 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.2. Experiment Goal . . . . . . . . . . . . . . . . . . . . . 3 2. The SMIMEA Resource Record . . . . . . . . . . . . . . . . . 4 3. Location of the SMIMEA Record . . . . . . . . . . . . . . . . 4 4. Email Address Variants and Internationalization Considerations . . . . . . . . . . . . . . . . . . . . . . . 5 5. Mandatory-to-Implement Features . . . . . . . . . . . . . . . 6 6. Application Use of S/MIME Certificate Associations . . . . . 6 7. Certificate Size and DNS . . . . . . . . . . . . . . . . . . 7 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 9. Security Considerations . . . . . . . . . . . . . . . . . . . 7 9.1. Response Size . . . . . . . . . . . . . . . . . . . . . . 8 9.2. Email Address Information Leak . . . . . . . . . . . . . 8 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 10.1. Normative References . . . . . . . . . . . . . . . . . . 9 10.2. Informative References . . . . . . . . . . . . . . . . . 10 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 1. Introduction S/MIME [RFC5751] messages often contain a certificate (some messages contain more than one certificate). These certificates assist in authenticating the sender of the message and can be used for encrypting messages that will be sent in reply. In order for the S/MIME receiver to authenticate that a message is from the sender identified in the message, the receiver's Mail User Agent (MUA) must validate that this certificate is associated with the purported sender. Currently, the MUA must trust a trust anchor upon which the sender's certificate is rooted and must successfully validate the certificate. There are other requirements on the MUA, such as associating the identity in the certificate with that of the message, that are out of scope for this document. Some people want to authenticate the association of the sender's certificate with the sender without trusting a configured trust anchor. Others to want mitigate the difficulty of finding certificates from outside the enterprise. Given that the DNS administrator for a domain name is authorized to give identifying information about the zone, it makes sense to allow that administrator to also make an authoritative binding between emailShow full document text