Internet DRAFT - draft-melnikov-spasm-eai-addresses
draft-melnikov-spasm-eai-addresses
Network Working Group A. Melnikov, Ed.
Internet-Draft Isode Ltd
Intended status: Standards Track W. Chuang, Ed.
Expires: November 27, 2016 Google, Inc.
May 26, 2016
Internationalized Email Addresses in X.509 certificates
draft-melnikov-spasm-eai-addresses-01
Abstract
This document defines a new name form for inclusion in the otherName
field of an X.509 Subject Alternative Name extension that allows a
certificate subject to be associated with an Internationalized Email
Address.
Status of This Memo
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This Internet-Draft will expire on November 27, 2016.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 2
3. Name Definitions . . . . . . . . . . . . . . . . . . . . . . 2
4. Matching of Internationalized Email Addresses in X.509
certificates . . . . . . . . . . . . . . . . . . . . . . . . 3
5. Name constraints in path validation . . . . . . . . . . . . . 3
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. Security Considerations . . . . . . . . . . . . . . . . . . . 4
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
8.1. Normative References . . . . . . . . . . . . . . . . . . 4
8.2. Informative References . . . . . . . . . . . . . . . . . 4
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
[RFC5280] defines rfc822Name subjectAltName choice for representing
[RFC5322] email addresses. This form is restricted to a subset of
US-ASCII characters and thus can't be used to represent
Internationalized Email addresses [RFC6531].
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].
The formal syntax use the Augmented Backus-Naur Form (ABNF) [RFC5234]
notation.
3. Name Definitions
This section defines the eaiName name as a form of otherName from the
GeneralName structure in SubjectAltName defined in [RFC5280].
id-on-eaiAddr OBJECT IDENTIFIER ::= { id-on XXX }
eaiName ::= UTF8String (SIZE (1..MAX))
When the subjectAltName extension contains an Internationalized Email
address, the address MUST be stored in the eaiName name form of
otherName. The format of eaiName is a eaiMailbox, and this is a
modified version of the internationalized Mailbox which is defined in
Section 3.3 of [RFC6531] which is itself derived from SMTP Mailbox
from Section 4.1.2 of [RFC5321]. [RFC6531] defines the following
ABNF rules for Mailbox whose parts are modified for
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internationalization: <Local-part>, <Dot-string>, <Quoted-string>,
<QcontentSMTP>, <Domain>, and <Atom>. In particular <Local-part> is
updated to also support UTF8-non-ascii. UTF8-non-ascii is described
by Section 3.1 of [RFC6532].
This document refines [RFC6531] Mailbox ABNF rules for eaiMailbox.
In eaiMailbox, Domain is restricted to a single format, the ASCII
Compatible Encoding (ACE) format (as defined in [RFC5280]), which
makes comparison simpler. With eaiMailbox comparison there is no
need to check for an alternate IDNA Domain form, nor convert from
IDNA to ACE format. Note that a eaiMailbox has no phrase (such as a
common name) before it, has no comment (text surrounded in
parentheses) after it, and is not surrounded by "<" and ">".
4. Matching of Internationalized Email Addresses in X.509 certificates
Comparison of two eaiName is straightforward. No setup work is
needed and it can be an octet for octet comparison. Comparison of
other email address forms such as Internationalized email address or
rfc822Name may require additional setup to normalize the format for
comparison. The <Local-part> part of an Internationalized email
address is in UTF-8, and the rfc822Name local-part MUST be converted
to UTF-8. The <Domain> for either International email address or
rfc822Name can contain either IDNA domain or an ASCII Compatible
Encoding (ACE) format. When comparing against eaiName, the <Domain>s
MUST be converted to the ACE form as described in section 7.2 of
[RFC5280] in UTF-8.
5. Name constraints in path validation
This section defines use of eaiName name for name constraints. The
format for eaiName in name constraints is identical to the use in
subjectAltName as specified in Section 3.
Constraint comparisons specified with eaiName name are only done on
the subjectAltName eaiName name, and says nothing more about
constaints on other email address forms. Constraint comparison on
complete email address with eaiName name uses the matching procedure
defined by Section 4. As with rfc822Name name constraints as
specified in Section 4.2.1.10 of [RFC5280], eaiName name can specify
a particular mailbox, all addresses at a host, or all mailboxes in a
domain by specifying the complete email address, a host name, or a
domain.
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6. IANA Considerations
[[CREF1: Just need a new OID.]]
7. Security Considerations
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
2003, <http://www.rfc-editor.org/info/rfc3629>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<http://www.rfc-editor.org/info/rfc5234>.
[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, DOI 10.17487/RFC5280, May 2008,
<http://www.rfc-editor.org/info/rfc5280>.
[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
DOI 10.17487/RFC5321, October 2008,
<http://www.rfc-editor.org/info/rfc5321>.
[RFC6531] Yao, J. and W. Mao, "SMTP Extension for Internationalized
Email", RFC 6531, DOI 10.17487/RFC6531, February 2012,
<http://www.rfc-editor.org/info/rfc6531>.
8.2. Informative References
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
DOI 10.17487/RFC5322, October 2008,
<http://www.rfc-editor.org/info/rfc5322>.
[RFC6532] Yang, A., Steele, S., and N. Freed, "Internationalized
Email Headers", RFC 6532, DOI 10.17487/RFC6532, February
2012, <http://www.rfc-editor.org/info/rfc6532>.
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Appendix A. Acknowledgements
Thank you to Magnus Nystrom for motivating this document. Thanks to
Nicolas Lidzborski, Laetitia Baudoin, and Ryan Sleevi for their early
feedback.
Authors' Addresses
Alexey Melnikov (editor)
Isode Ltd
14 Castle Mews
Hampton, Middlesex TW12 2NP
UK
Email: Alexey.Melnikov@isode.com
Weihaw Chuang (editor)
Google, Inc.
1600 Amphitheatre Parkway
Mountain View, CA 94043
US
Email: weihaw@google.com
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