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Network Working Group                                        A. Melnikov
Internet-Draft                                                 Isode Ltd
Intended status: Informational                                   G. Lunt
Expires: December 21, 2013                                       A. Ross
                                                                SMHS Ltd
                                                           June 19, 2013


           Military Message Handling System (MMHS) over SMTP
                     draft-melnikov-mmhs-profile-04

Abstract

   A Military Message Handling System (MMHS) processes formal messages
   ensuring release, distribution, security, and timely delivery across
   national and international strategic and tactical networks.  The MMHS
   Elements of Service are defined as a set of extensions to the ITU-T
   X.400 (1992) international standards and are specified in STANAG 4406
   Edition 2 or ACP 123.  This document specifies how a comparable
   messaging service can be provided using SMTP and its extensions.

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
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

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   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 December 21, 2013.

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



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   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   4
   3.  Elements of Service . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Introduction  . . . . . . . . . . . . . . . . . . . . . .   5
     3.2.  Profile Support . . . . . . . . . . . . . . . . . . . . .   5
     3.3.  Basic Elements of Service . . . . . . . . . . . . . . . .  15
       3.3.1.  Access Management . . . . . . . . . . . . . . . . . .  15
       3.3.2.  Content Type Indication . . . . . . . . . . . . . . .  15
       3.3.3.  Converted Indication  . . . . . . . . . . . . . . . .  16
       3.3.4.  Delivery Time Stamp Indication  . . . . . . . . . . .  16
       3.3.5.  MM Identification . . . . . . . . . . . . . . . . . .  16
       3.3.6.  Message Identification  . . . . . . . . . . . . . . .  16
       3.3.7.  Non-delivery Notification . . . . . . . . . . . . . .  16
       3.3.8.  Original Encoded Information Types  . . . . . . . . .  17
       3.3.9.  Submission Time Stamp Indication  . . . . . . . . . .  17
       3.3.10. Typed Body  . . . . . . . . . . . . . . . . . . . . .  17
       3.3.11. User/UA Capabilities Registration . . . . . . . . . .  17
     3.4.  Optional Elements of Service  . . . . . . . . . . . . . .  17
       3.4.1.  Alternate Recipient Allowed . . . . . . . . . . . . .  17
       3.4.2.  Alternate Recipient Assignment  . . . . . . . . . . .  18
       3.4.3.  Authorizing Users Indication  . . . . . . . . . . . .  18
       3.4.4.  Auto-forwarded Indication . . . . . . . . . . . . . .  18
       3.4.5.  Blind Copy Recipient Indication . . . . . . . . . . .  19
       3.4.6.  Body Part Encryption Indication . . . . . . . . . . .  19
       3.4.7.  Conversion Prohibited . . . . . . . . . . . . . . . .  19
       3.4.8.  Conversion Prohibition in Case of Loss of Information  20
       3.4.9.  Cross Referencing Indication  . . . . . . . . . . . .  20
       3.4.10. Deferred Delivery . . . . . . . . . . . . . . . . . .  20
       3.4.11. Deferred Delivery Cancellation  . . . . . . . . . . .  20
       3.4.12. Delivery Notification . . . . . . . . . . . . . . . .  20
       3.4.13. Designation of Recipient by Directory Name  . . . . .  21
       3.4.14. Disclosure of Other Recipients  . . . . . . . . . . .  21
       3.4.15. DL Expansion History Indication . . . . . . . . . . .  21
       3.4.16. DL Expansion Prohibited . . . . . . . . . . . . . . .  22
       3.4.17. Expiry Date Indication  . . . . . . . . . . . . . . .  22
       3.4.18. Explicit Conversion . . . . . . . . . . . . . . . . .  22
       3.4.19. Forwarded MM Indication . . . . . . . . . . . . . . .  22
       3.4.20. Grade of Delivery Selection . . . . . . . . . . . . .  23
       3.4.21. Hold for Delivery . . . . . . . . . . . . . . . . . .  23
       3.4.22. Incomplete Copy Indication  . . . . . . . . . . . . .  23
       3.4.23. Language Indication . . . . . . . . . . . . . . . . .  23



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       3.4.24. Latest Delivery Designation . . . . . . . . . . . . .  24
       3.4.25. Multi-destination Delivery  . . . . . . . . . . . . .  24
       3.4.26. Multi-part Body . . . . . . . . . . . . . . . . . . .  24
       3.4.27. Non-receipt Notification Request Indication . . . . .  24
       3.4.28. Obsoleting Indication . . . . . . . . . . . . . . . .  24
       3.4.29. Originator Indication . . . . . . . . . . . . . . . .  25
       3.4.30. Originator Requested Alternate Recipient  . . . . . .  25
       3.4.31. Prevention of Non-delivery Notification . . . . . . .  25
       3.4.32. Primary and Copy Recipients Indication  . . . . . . .  25
       3.4.33. Receipt Notification Request Indication . . . . . . .  26
       3.4.34. Redirection Disallowed by Originator  . . . . . . . .  26
       3.4.35. Redirection of Incoming Messages  . . . . . . . . . .  27
       3.4.36. Reply Request Indication  . . . . . . . . . . . . . .  27
       3.4.37. Replying MM Indication  . . . . . . . . . . . . . . .  27
       3.4.38. Requested Preferred Delivery Method . . . . . . . . .  28
       3.4.39. Subject Indication  . . . . . . . . . . . . . . . . .  28
       3.4.40. Use of Distribution List  . . . . . . . . . . . . . .  28
     3.5.  Military Elements of Service  . . . . . . . . . . . . . .  28
       3.5.1.  Primary Precedence  . . . . . . . . . . . . . . . . .  28
       3.5.2.  Copy Precedence . . . . . . . . . . . . . . . . . . .  28
       3.5.3.  Message Type  . . . . . . . . . . . . . . . . . . . .  28
       3.5.4.  Exempted Addresses  . . . . . . . . . . . . . . . . .  28
       3.5.5.  Extended Authorization Info . . . . . . . . . . . . .  28
       3.5.6.  Distribution Code . . . . . . . . . . . . . . . . . .  29
       3.5.7.  Message Instructions  . . . . . . . . . . . . . . . .  29
       3.5.8.  Clear Service . . . . . . . . . . . . . . . . . . . .  29
       3.5.9.  Other Recipient Indicator . . . . . . . . . . . . . .  29
       3.5.10. Originator Reference  . . . . . . . . . . . . . . . .  29
       3.5.11. Use of Address List . . . . . . . . . . . . . . . . .  29
     3.6.  Transition Elements of Service  . . . . . . . . . . . . .  29
       3.6.1.  Handling Instructions . . . . . . . . . . . . . . . .  29
       3.6.2.  Pilot Forwarded . . . . . . . . . . . . . . . . . . .  29
       3.6.3.  Corrections . . . . . . . . . . . . . . . . . . . . .  30
       3.6.4.  ACP 127 Message Identifier  . . . . . . . . . . . . .  30
       3.6.5.  Originator PLAD . . . . . . . . . . . . . . . . . . .  30
       3.6.6.  Codress Message Indicator . . . . . . . . . . . . . .  30
       3.6.7.  ACP 127 Notification Request  . . . . . . . . . . . .  30
       3.6.8.  ACP 127 Notification Response . . . . . . . . . . . .  30
   4.  Security Services . . . . . . . . . . . . . . . . . . . . . .  30
     4.1.  Elements of Service . . . . . . . . . . . . . . . . . . .  31
       4.1.1.  Access Control  . . . . . . . . . . . . . . . . . . .  31
       4.1.2.  Authentication of Origin  . . . . . . . . . . . . . .  31
       4.1.3.  Non-repudiation of Origin . . . . . . . . . . . . . .  32
       4.1.4.  Message Integrity . . . . . . . . . . . . . . . . . .  32
       4.1.5.  Message Data Separation . . . . . . . . . . . . . . .  33
       4.1.6.  Security Labels . . . . . . . . . . . . . . . . . . .  33
       4.1.7.  Non-repudiation of Receipt  . . . . . . . . . . . . .  33
       4.1.8.  Secure Mailing Lists  . . . . . . . . . . . . . . . .  33



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       4.1.9.  Message Counter Signature . . . . . . . . . . . . . .  34
       4.1.10. Certificate Binding . . . . . . . . . . . . . . . . .  34
       4.1.11. Compressed Data . . . . . . . . . . . . . . . . . . .  34
     4.2.  Security Profile  . . . . . . . . . . . . . . . . . . . .  35
       4.2.1.  S/MIME Cryptographic Message Syntax Content Types . .  35
       4.2.2.  S/MIME Triple Wrapping  . . . . . . . . . . . . . . .  38
       4.2.3.  DKIM Digital Signatures . . . . . . . . . . . . . . .  38
       4.2.4.  Security Labels . . . . . . . . . . . . . . . . . . .  40
       4.2.5.  Message Header Fields . . . . . . . . . . . . . . . .  40
   5.  Requirements on Mail User Agents  . . . . . . . . . . . . . .  41
     5.1.  Standards Compliance  . . . . . . . . . . . . . . . . . .  41
     5.2.  Audit Trail and Logging . . . . . . . . . . . . . . . . .  42
   6.  Requirements on Mail Submission Agents  . . . . . . . . . . .  42
     6.1.  Standards Compliance  . . . . . . . . . . . . . . . . . .  42
     6.2.  Audit Trail and Logging . . . . . . . . . . . . . . . . .  42
   7.  Requirements on Mail Transfer Agents  . . . . . . . . . . . .  43
     7.1.  Standards Compliance  . . . . . . . . . . . . . . . . . .  43
     7.2.  Audit Trail and Logging . . . . . . . . . . . . . . . . .  43
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  43
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  43
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  44
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  44
     10.2.  Informative References . . . . . . . . . . . . . . . . .  47
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .  47

1.  Introduction

   A Military Message Handling System (MMHS) processes formal messages
   ensuring release, distribution, security, and timely delivery across
   national and international strategic and tactical networks.  The MMHS
   Elements of Service are defined as a set of extensions to the ITU-T
   X.400 (1992) international standards and are specified in STANAG 4406
   Edition 2 or ACP 123.  This document specifies how a comparable
   messaging service can be provided using Email Message Format
   [RFC5322], SMTP [RFC5321] and their extensions.

   [[TODO: Discuss MUA, MSA, MS and MTA.  Are we going to cite IMAP/POP
   standards?]]

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.  Elements of Service





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3.1.  Introduction

   The military messaging elements of service are adopted from [ACP123].

   Many of these elements of service are derived from the X.400
   standards upon which [ACP123] is based.

   Note that some of the X.400 elements of service do not have an
   equivalent in a SMTP messaging system.  It is not the intention of
   this profile to define additional SMTP functionality and consequently
   a number of the military messaging elements of service are not
   supported by this profile.

   Specifically, the physical delivery, conversion (implicit or
   explicit) and alternate recipient elements of service are not
   supported by this profile.

   This profile adopts, where appropriate, header fields that are
   defined in [RFC2156] to support X.400 elements of service that
   support military messaging elements of service.  [RFC2156] has
   already addressed the issue of conveying many of the X.400 elements
   of service within an SMTP messaging system.

3.2.  Profile Support

   +-------------+---------+-------+--------+--------------------------+
   | Element of  | ACP123  | Suppo | IETF S | Header Field/Parameter   |
   | Service     | Referen | rt    | tandar |                          |
   |             | ce      |       | d      |                          |
   +-------------+---------+-------+--------+--------------------------+
   | Access      | 205a    | MUST  | N/A    | N/A                      |
   | Management  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.3.1)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Content     | 205b    | MUST  | [RFC64 | MMHS-Extended-           |
   | Type        |         |       | 77],   | Authorization-Info       |
   | Indication  |         |       | 3.2    |                          |
   | (Section    |         |       |        |                          |
   | 3.3.2)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Converted   | 205c    | N/A   | N/A    | N/A                      |
   | Indication  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.3.3)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Delivery    | 205d    | MUST  | [RFC53 | Received                 |
   | Time Stamp  |         |       | 22],   |                          |



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   | Indication  |         |       | 3.6.7  |                          |
   | (Section    |         |       |        |                          |
   | 3.3.4)      |         |       |        |                          |
   |             |         |       |        |                          |
   | MM Identifi | 205e    | MUST  | [RFC53 | Message-ID               |
   | cation      |         |       | 22],   |                          |
   | (Section    |         |       | 3.6.4  |                          |
   | 3.3.5)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Message Ide | 205f    | MUST  | [RFC34 | ENVID                    |
   | ntification |         |       | 61],   |                          |
   | (Section    |         |       | 4.4    |                          |
   | 3.3.6)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Non-        | 205g    | MUST  | [RFC34 | NOTIFY=FAILURE           |
   | delivery No |         |       | 61],   |                          |
   | tification  |         |       | 4.1    |                          |
   | (Section    |         |       |        |                          |
   | 3.3.7)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Original    | 205h    | MAY   | [RFC21 | Original-Encoded-        |
   | Encoded     |         |       | 56], 2 | Information-Types        |
   | Information |         |       | .3.1.1 |                          |
   | Types       |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.3.8)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Submission  | 205i    | MUST  | [RFC53 | Received                 |
   | Time Stamp  |         |       | 22],   |                          |
   | Indication  |         |       | 3.6.7  |                          |
   | (Section    |         |       |        |                          |
   | 3.3.9)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Typed Body  | 205j    | MUST  | [RFC20 | Content-Type             |
   | (Section    |         |       | 45], 5 |                          |
   | 3.3.10)     |         |       |        |                          |
   |             |         |       |        |                          |
   | User/UA Cap | 205k    | N/A   | N/A    | N/A                      |
   | abilities R |         |       |        |                          |
   | egistration |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.3.11)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Alternate   | 206a    | N/A   | N/A    | N/A                      |
   | Recipient   |         |       |        |                          |
   | Allowed     |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.1)      |         |       |        |                          |



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   |             |         |       |        |                          |
   | Alternate   | 206b    | N/A   | N/A    | N/A                      |
   | Recipient   |         |       |        |                          |
   | Assignment  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.2)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Authorizing | 206c    | MUST  | [RFC53 | From                     |
   | Users       |         |       | 22],   |                          |
   | Indication  |         |       | 3.6.2  |                          |
   | (Section    |         |       |        |                          |
   | 3.4.3)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Auto-       | 206d    | MAY   | [RFC21 | Auto-forwarded           |
   | forwarded   |         |       | 56], 2 |                          |
   | Indication  |         |       | .3.1.2 |                          |
   | (Section    |         |       |        |                          |
   | 3.4.4)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Blind Copy  | 206e    | MUST  | [RFC53 | Bcc                      |
   | Recipient   |         |       | 22],   |                          |
   | Indication  |         |       | 3.6.3  |                          |
   | (Section    |         |       |        |                          |
   | 3.4.5)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Body Part   | 206f    | N/A   | N/A    | N/A                      |
   | Encryption  |         |       |        |                          |
   | Indication  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.6)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Conversion  | 206g    | MAY   | [RFC21 | Conversion               |
   | Prohibited  |         |       | 56],   |                          |
   | (Section    |         |       | 5.3.6  |                          |
   | 3.4.7)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Conversion  | 206h    | MAY   | [RFC21 | Conversion-With-Loss     |
   | Prohibition |         |       | 56],   |                          |
   | in Case of  |         |       | 5.3.6  |                          |
   | Loss of     |         |       |        |                          |
   | Information |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.8)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Cross       | 206i    | MAY   | [RFC53 | References               |
   | Referencing |         |       | 22],   |                          |
   | Indication  |         |       | 3.6.4  |                          |
   | (Section    |         |       |        |                          |



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   | 3.4.9)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Deferred    | 206j    | MAY   | [RFC48 | HOLDUNTIL                |
   | Delivery    |         |       | 65],   |                          |
   | (Section    |         |       | 3.6.4  |                          |
   | 3.4.10)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Deferred    | 206k    | N/A   | N/A    | N/A                      |
   | Delivery Ca |         |       |        |                          |
   | ncellation  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.11)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Delivery No | 206l    | MUST  | [RFC34 | NOTIFY=SUCCESS           |
   | tification  |         |       | 61],   |                          |
   | (Section    |         |       | 4.1    |                          |
   | 3.4.12)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Designation | 206m    | N/A   | N/A    | N/A                      |
   | of          |         |       |        |                          |
   | Recipient   |         |       |        |                          |
   | by          |         |       |        |                          |
   | Directory   |         |       |        |                          |
   | Name        |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.13)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Disclosure  | 206n    | N/A   | N/A    | N/A                      |
   | of Other    |         |       |        |                          |
   | Recipients  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.14)     |         |       |        |                          |
   |             |         |       |        |                          |
   | DL          | 206o    | N/A   | N/A    | N/A                      |
   | Expansion   |         |       |        |                          |
   | History     |         |       |        |                          |
   | Indication  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.15)     |         |       |        |                          |
   |             |         |       |        |                          |
   | DL          | 206p    | N/A   | N/A    | N/A                      |
   | Expansion   |         |       |        |                          |
   | Prohibited  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.16)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Expiry Date | 206q    | MUST  | [RFC21 | Expires                  |
   | Indication  |         |       | 56], 2 |                          |



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   | (Section    |         |       | .3.1.2 |                          |
   | 3.4.17)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Explicit    | 206r    | N/A   | N/A    | N/A                      |
   | Conversion  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.18)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Forwarded   | 206s    | MUST  | [RFC20 | Content-Type:            |
   | MM          |         |       | 46],   | message/rfc822           |
   | Indication  |         |       | 5.2    |                          |
   | (Section    |         |       |        |                          |
   | 3.4.19)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Grade of    | 206t    | MUST  | [RFC67 | MT-Priority              |
   | Delivery    |         |       | 58]    |                          |
   | Selection   |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.20)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Hold for    | 206u    | N/A   | N/A    | N/A                      |
   | Delivery    |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.21)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Incomplete  | 206v    | MAY   | [RFC21 | Incomplete-Copy          |
   | Copy        |         |       | 56], 2 |                          |
   | Indication  |         |       | .3.1.2 |                          |
   | (Section    |         |       |        |                          |
   | 3.4.22)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Language    | 206w    | MAY   | [RFC32 | Content-Language         |
   | Indication  |         |       | 82], 2 |                          |
   | (Section    |         |       |        |                          |
   | 3.4.23)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Latest      | 206x    | MUST  | [RFC28 | BY                       |
   | Delivery    |         |       | 52], 4 |                          |
   | Designation |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.24)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Multi-      | 206y    | MUST  | [RFC53 | RCPT TO                  |
   | destination |         |       | 21],   |                          |
   | Delivery    |         |       | 2.1    |                          |
   | (Section    |         |       |        |                          |
   | 3.4.25)     |         |       |        |                          |
   |             |         |       |        |                          |



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   | Multi-part  | 206z    | MUST  | [RFC20 | Content-Type:            |
   | Body        |         |       | 46],   | multipart/mixed          |
   | (Section    |         |       | 25.1.3 |                          |
   | 3.4.26)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Non-receipt | 206aa   | MUST  | [RFC37 | Disposition-             |
   | Notificatio |         |       | 98],   | Notification-To          |
   | n Request   |         |       | 2.1    |                          |
   | Indication  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.27)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Obsoleting  | 206ab   | MAY   | [RFC21 | Supersedes               |
   | Indication  |         |       | 56], 2 |                          |
   | (Section    |         |       | .3.1.2 |                          |
   | 3.4.28)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Originator  | 206ac   | MUST  | [RFC53 | Sender                   |
   | Indication  |         |       | 22],   |                          |
   | (Section    |         |       | 3.6.2  |                          |
   | 3.4.29)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Originator  | 206ad   | N/A   | N/A    | N/A                      |
   | Requested   |         |       |        |                          |
   | Alternate   |         |       |        |                          |
   | Recipient   |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.30)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Prevent of  | 206ae   | MAY   | [RFC34 | NOTIFY=NEVER             |
   | Non-        |         |       | 61],   |                          |
   | delivery No |         |       | 4.1    |                          |
   | tification  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.31)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Primary and | 206af   | MAY   | [RFC53 | To, Cc                   |
   | Copy        |         |       | 22],   |                          |
   | Recipients  |         |       | 3.6.3  |                          |
   | Indication  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.32)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Receipt Not | 206ag   | MUST  | [RFC37 | Disposition-             |
   | ification   |         |       | 98],   | Notification-To          |
   | Request     |         |       | 2.1    |                          |
   | Indication  |         |       |        |                          |
   | (Section    |         |       |        |                          |



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   | 3.4.33)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Redirection | 206ah   | N/A   | N/A    | N/A                      |
   | Disallowed  |         |       |        |                          |
   | By          |         |       |        |                          |
   | Originator  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.34)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Redirection | 206ai   | N/A   | [RFC52 | N/A                      |
   | of Incoming |         |       | 28],   |                          |
   | Messages    |         |       | 4.2?   |                          |
   | (Section    |         |       | Maybe? |                          |
   | 3.4.35)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Reply       | 206ab   | N/A   | [RFC53 | N/A                      |
   | Request     |         |       | 22] -  |                          |
   | Indication  |         |       | no req |                          |
   | (Section    |         |       | uestin |                          |
   | 3.4.36)     |         |       | g mech |                          |
   |             |         |       | anism  |                          |
   |             |         |       |        |                          |
   | Replying MM | 206ak   | MUST  | [RFC21 | In-Reply-To              |
   | Indication  |         |       | 56],   |                          |
   | (Section    |         |       | 3.6.4  |                          |
   | 3.4.37)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Requested   | 206al   | N/A   | N/A    | N/A                      |
   | Preferred   |         |       |        |                          |
   | Delivery    |         |       |        |                          |
   | Method      |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.38)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Subject     | 206am   | MAY   | [RFC21 | Subject                  |
   | Indication  |         |       | 56],   |                          |
   | (Section    |         |       | 3.6.5  |                          |
   | 3.4.39)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Use of Dist | 206an   | N/A   | N/A    | N/A                      |
   | ribution    |         |       |        |                          |
   | List        |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.4.40)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Primary     | 212a    | MUST  | [RFC64 | MMHS-Primary-Precedence  |
   | Precedence  |         |       | 77],   |                          |
   | (Section    |         |       | 3.8    |                          |



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   | 3.5.1)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Copy        | 212b    | MUST  | [RFC64 | MMHS-Copy-Precedence     |
   | Precedence  |         |       | 77],   |                          |
   | (Section    |         |       | 3.9    |                          |
   | 3.5.2)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Message     | 212c    | MUST  | [RFC64 | MMHS-Message-Type        |
   | Type        |         |       | 77],   |                          |
   | (Section    |         |       | 3.10   |                          |
   | 3.5.3)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Exempted    | 212d    | MAY   | [RFC64 | MMHS-Exempted-Address    |
   | Addresses   |         |       | 77],   |                          |
   | (Section    |         |       | 3.1    |                          |
   | 3.5.4)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Extended Au | 212e    | MAY   | [RFC64 | MMHS-Extended-           |
   | thorization |         |       | 77],   | Authorisation-Info       |
   | Info        |         |       | 3.2    |                          |
   | (Section    |         |       |        |                          |
   | 3.5.5)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Distributio | 212f    | MAY   | [RFC64 | MMHS-Subject-Indicator-  |
   | n Code      |         |       | 77],   | Codes                    |
   | (Section    |         |       | 3.3    |                          |
   | 3.5.6)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Message Ins | 212g    | MAY   | [RFC64 | MMHS-Message-            |
   | tructions   |         |       | 77],   | Instructions             |
   | (Section    |         |       | 3.5    |                          |
   | 3.5.7)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Clear       | 212h    | MAY   | [RFC26 | eSSSecurityLabel, SIO-   |
   | Service     |         |       | 34], 3 | Label                    |
   | (Section    |         |       |        |                          |
   | 3.5.8)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Other       | 212i    | MAY   | [RFC64 | MMHS-Other-Recipient-    |
   | Recipient   |         |       | 77],   | Indicator-To, MMHS-      |
   | Indicator   |         |       | 3.11   | Other-Recipients-        |
   | (Section    |         |       | 3.12   | Indicator-CC             |
   | 3.5.9)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Originator  | 212j    | MAY   | [RFC64 | MMHS-Originator-Address  |
   | Reference   |         |       | 77],   |                          |
   | (Section    |         |       | 3.7    |                          |
   | 3.5.10)     |         |       |        |                          |



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   |             |         |       |        |                          |
   | Use of      | 212k    | TBD   | TBD    | TBD                      |
   | Address     |         |       |        |                          |
   | List        |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.5.11)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Handling In | 213a    | MAY   | [RFC64 | MMHS-Handling-           |
   | structions  |         |       | 77],   | Instructions             |
   | (Section    |         |       | 3.4    |                          |
   | 3.6.1)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Pilot       | 213b    | N/A   | N/A    | N/A                      |
   | Forwarded   |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.6.2)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Corrections | 213c    | TBD   | appror | TBD                      |
   | (Section    |         |       | iate   |                          |
   | 3.6.3)      |         |       | MIME   |                          |
   |             |         |       | type?  |                          |
   |             |         |       |        |                          |
   | ACP 127     | 213d    | MAY   | [RFC64 | MMHS-Acp127-Message-     |
   | Message     |         |       | 77],   | Identifier               |
   | Identifier  |         |       | 3.13   |                          |
   | (Section    |         |       |        |                          |
   | 3.6.4)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Originator  | 213e    | MAY   | [RFC64 | MMHS-Originator-PLAD     |
   | PLAD        |         |       | 77],   |                          |
   | (Section    |         |       | 3.14   |                          |
   | 3.6.5)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Codress     | 213f    | MAY   | [RFC64 | MMHS-Codress-Message-    |
   | Message     |         |       | 77],   | Indicator                |
   | Indicator   |         |       | 3.6    |                          |
   | (Section    |         |       |        |                          |
   | 3.6.6)      |         |       |        |                          |
   |             |         |       |        |                          |
   | ACP 127 Not | 213g    | N/A   | N/A    | N/A                      |
   | ification   |         |       |        |                          |
   | Request     |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 3.6.7)      |         |       |        |                          |
   |             |         |       |        |                          |
   | ACP 127 Not | 213h    | N/A   | N/A    | N/A                      |
   | ification   |         |       |        |                          |
   | Response    |         |       |        |                          |



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   | (Section    |         |       |        |                          |
   | 3.6.8)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Access      | Annex   | MAY   | TBD    | TBD                      |
   | Control     | B, 7.1  |       |        |                          |
   | (Section    |         |       |        |                          |
   | 4.1.1)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Authenticat | Annex   | MAY   | [RFC56 | SignedData               |
   | ion of      | B, 7.2  |       | 52], 5 |                          |
   | Origin      |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 4.1.2)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Non-        | Annex   | MAY   | [RFC56 | SignedData               |
   | repudiation | B, 7.3  |       | 52], 5 |                          |
   | of Origin   |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 4.1.3)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Message     | Annex   | MUST  | [RFC56 | SignedData               |
   | Integrity   | B, 7.4  |       | 52], 5 |                          |
   | (Section    |         |       |        |                          |
   | 4.1.4)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Message     | Annex   | MAY   | [RFC56 | EnvelopedData            |
   | Data        | B, 7.5  |       | 52], 6 |                          |
   | Separation  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 4.1.5)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Security    | Annex   | MUST  | [RFC26 | ESSSecurityLabel         |
   | Labels      | B, 7.6  |       | 34], 3 |                          |
   | (Section    |         |       |        |                          |
   | 4.1.6)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Non-        | Annex   | MAY   | [RFC26 | ReceiptRequest           |
   | repudiation | B, 7.7  |       | 34], 2 |                          |
   | of Receipt  |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 4.1.7)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Secure      | Annex   | MAY   | [RFC26 | MLExpansionHistory       |
   | Mailing     | B, 7.8  |       | 34], 4 |                          |
   | Lists       |         |       |        |                          |
   | (Section    |         |       |        |                          |
   | 4.1.8)      |         |       |        |                          |
   |             |         |       |        |                          |



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   | Message     | Annex   | MAY   | [RFC56 | counterSignature         |
   | Counter     | B, 7.9  |       | 52],   |                          |
   | Signature   |         |       | 11.4   |                          |
   | (Section    |         |       |        |                          |
   | 4.1.9)      |         |       |        |                          |
   |             |         |       |        |                          |
   | Certificate | Annex   | MAY   | [RFC26 | SigningCertificate       |
   | Binding     | B, 7.10 |       | 34],   |                          |
   | (Section    |         |       |        |                          |
   | 4.1.10)     |         |       |        |                          |
   |             |         |       |        |                          |
   | Compressed  | Annex   | MAY   | [RFC32 | CompressedData           |
   | Data        | B, 7.11 |       | 74]    |                          |
   | (Section    |         |       |        |                          |
   | 4.1.11)     |         |       |        |                          |
   +-------------+---------+-------+--------+--------------------------+


3.3.  Basic Elements of Service

3.3.1.  Access Management

   This element of service enables an Mail User Agent and an Mail
   Transfer Agent to establish access and manage information associated
   with access establishment.  This includes the ability to identify and
   validate the identity of the other.

   Strong authentication in the bind operation is mandatory.  Strong
   authentication MUST be supported using SMTP Extension for
   Authentication [RFC4954] and SMTP Extension for Secure SMTP over TLS
   [RFC3207].

   [[Q: Do we need to identify the SASL mechanisms to use here?]]

3.3.2.  Content Type Indication

   This element of service enables an originating Mail User Agent to
   indicate the type of each submitted message.  In most cases, the
   content type will be obvious from the header fields that are present.

   A Military Message MUST be indicated using the MMHS-Extended-
   Authorization-Info header field defined in [RFC6477].









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3.3.3.  Converted Indication

   [[TBD]]

3.3.4.  Delivery Time Stamp Indication

   This element of service indicates to each recipient Mail User Agent
   (i.e., on a per-recipient basis), the date and time at which the Mail
   Transfer Agent delivered a message.

   The delivery time stamp MUST be determined from the first Received
   header field, defined in [RFC5322], present in the message.

3.3.5.  MM Identification

   This element of service enables cooperating Mail User Agents to
   convey a globally unique identifier for each Military Message sent or
   received.  This identifier is used in subsequent messages to identify
   the original Military Message.

   A Military Message MUST be uniquely identified using the Message-ID
   header field defined in [RFC5322].

3.3.6.  Message Identification

   This element of service is used by Mail User Agents and the Mail
   Transfer Agents to refer to a previously submitted message in
   connection with other elements of service such as delivery and non-
   delivery notification.

   Message Identification MUST be specified by the Mail User Agent using
   the ENVID parameter, as defined in [RFC3461].  The Mail Transfer
   Agent MUST return the message identification in the Original-
   Envelope-Id field of a message/delivery status as defined in
   [RFC3461].

3.3.7.  Non-delivery Notification

   This element of service allows a Mail User Agent to ask for the MTS
   to notify the originator if a submitted message was not delivered to
   the specified recipient Mail User Agent.  The MMHS must, with a high
   degree of certainty, deliver a message to the intended recipient(s).
   If the system cannot deliver a message within a determined period of
   time , a non-delivery report will be returned to the originating Mail
   User Agent by the MMHS.  The non-delivery report contains information
   to enable it to be mapped to the appropriate message (i.e., the
   message identification), recipient information, as well as
   information about why the message could not be delivered.



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   Non-Delivery notifications MUST be generated in accordance with
   [RFC3461].

   Note that non-delivery notifications are requested on a per message
   basis in this profile, and not on a per recipient basis as defined in
   [ACP123].

3.3.8.  Original Encoded Information Types

   This element of service enables the originating Mail User Agent to
   indicate the various formats of the bodyparts of a message.

   The Original Encoded Information Types, if present, MUST use the
   Original-Encoded-Information-Types header field as defined in
   [RFC2156].

3.3.9.  Submission Time Stamp Indication

   This element of service enables the Message Transfer Agent to
   indicate to the originating Mail User Agent and each recipient Mail
   User Agent the date and time at which is which was submitted to the
   Message Transfer Agent.

   The Submission Time Stamp Indication MUST use the determined from the
   last Received header field, as defined in [RFC5322], present in the
   message.  Note that this is distinct from the Date header field,
   defined in [RFC5322], which is more likely to be displayed by a
   receiving Mail User Agent but which indicates the date and time at
   which the originator of the message indicated that the message was
   complete and ready to submitted.

3.3.10.  Typed Body

   This element of service allows the nature of attributes of the body
   of the message to be conveyed along with the body.

3.3.11.  User/UA Capabilities Registration

   [[TBD: do we want to talk about IMAP?]]

3.4.  Optional Elements of Service

3.4.1.  Alternate Recipient Allowed








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   This element of service enables an originating Mail User Agent to
   specify that the message being submiited can be redirected to an
   alternate recipient.  Unless an originator specifically request that
   an alternate recipient be disallowed, all Military Messages will
   indicate that an alternate recipient is allowed.

   There is no current SMTP service that supports allows the originator
   to disallow the redirection of a message to an alternate recipient.
   Therefore this profile does not support the Alternate Recipient
   Allowed element of service.  [[ We could refer to MIXER field to
   allow control within X.400 domains, even though not supported within
   SMTP domains?]]

3.4.2.  Alternate Recipient Assignment

   This element of service enables a receiving Mail User Agent to be
   given the capability to have certain messages delivered to it for
   which there is not an exact match between the recipient address
   specified in the message and the valid addresses within the recipient
   domain.  This service allows a message that would otherwise be
   undeliverable to be delivered to a "default mailbox" within the
   recipient domain.

   There is no current SMTP service that supports allows the Alternate
   Recipient Assignment element of service.  Therefore this profile does
   not support the Alternate Recipient Assignment element of service.
   Note that some Mail Transfer Agent products may provide propriertary
   mechanisms that support the element of service.

3.4.3.  Authorizing Users Indication

   This element of service allows the originator to indicate to the
   recipient the names or one or more persons who authorized the sending
   of the messages.

   The Authorizing Users Indication MUST use the From header field, as
   defined in [RFC5322], present in the message and in addition the
   Sender header field (carrying the Originator Indication) MUST also be
   present in accordance with [RFC2156].

3.4.4.  Auto-forwarded Indication

   This element of service allows a recipient to determine that the body
   of an incoming Military Message contains a Military Message that has
   been auto-forwarded by an autonomous Mail Submission Agent.  This is
   used to distinguish the incoming Military Message that contains a
   Military Message that was manually forwarded by the original
   recipient.  If automatic forwarding of Military Messages is supported



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   by a Mail Submission Agent, then the Auto-forwarded Indication MUST
   be supported on origination.

   The Auto-forwared Indication MUST use the Autoforwarded header field,
   as defined in [RFC2156].

3.4.5.  Blind Copy Recipient Indication

   This element of service enable the originator to provide the address
   of one or more additional intended recipients of the message being
   sent.  These names are not disclosed to the primary, copy or other
   blind copy recipients.  This service can be used to keep some
   recipient names and addressed hidden from other recipients.  This
   service can be used to send a courtesy copy to drafters or reviewers
   of a message, when internal information, such as who drafted or
   reviewed the message, is not to be disclosed to the recipient(s).
   Separate copies of the mesage MUST be submitted to the Mail Transfer
   Agent for the open recipients (primary and copy recipients) and for
   each blind copy recipient.  The messages sent to each of blind copy
   recipients MUST contain same MM Identification as the message sent to
   the open recipients.

   The Blind Copy Recipient Indication MUST use the Bcc header field, as
   defined in [RFC5322].

3.4.6.  Body Part Encryption Indication

   This element of service allows the originator to indicate to the
   recipient that a particular body of the message has been sent
   encrypted.

   There is no current SMTP service that supports allows the Body Part
   Encryption Indication element of service.  Therefore this profile
   does not support the Body Part Encryption Indication element of
   service.  [[Refer to whole message encryption options]].

3.4.7.  Conversion Prohibited

   This element of service enables an originating Mail User Agent to
   instruct the Mail Transfer Agent that the implicit conversion of the
   military message should not be performed.

   This element of service is not supported by an SMTP Mail Transfer
   Agent.  A Mail User Agent MAY use the Conversion header field, as
   defined in [RFC2156] to control the conversion to an X.400 message at
   a MIXER gateway and further within the X.400 domain at X.400 Mail
   Transfer Agents.




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3.4.8.  Conversion Prohibition in Case of Loss of Information

   This element of service enables and originating Mail User Agent to
   instruct the Mail Transfer Agent that the implicit conversion of the
   military message should not be performed, if such conversion would
   result in the loss of information.

   This element of service is not supported by an SMTP Mail Transfer
   Agent.  A Mail User Agent MAY use the Conversion-With-Loss header
   field, as defined in [RFC2156] to control the conversion to an X.400
   message at a MIXER gateway and further within the X.400 domain at
   X.400 Mail Transfer Agents.

3.4.9.  Cross Referencing Indication

   This element of service allows the originator to associate the
   globally unique identifiers of one or more other messages with the
   message being sent.  This enables the recipient's Mail User Agent,
   for example, to retrieve a copy of the referenced messages.

   The Cross Referencing Indication MUST use the References header
   field, as defined in [RFC5322].

3.4.10.  Deferred Delivery

   This element of service enables an originating Mail User Agent to
   instruct the Mail Transfer Agent that a military message being
   submitted shall be delivered no sooner than a specified date and
   time.  When this service is requested, it MUST be logged for audit
   and tracing purposes.

   Deferred Delivery MUST be specified in accordance with [RFC4865]

3.4.11.  Deferred Delivery Cancellation

   This element of service enables an orginating MUA to instruct the MTA
   to cancel a previously submitted military message that contained a
   Deferred Delivery date and time.

   Deferred Delivery Cancellation is not supported by this profile.

3.4.12.  Delivery Notification

   This element of service enables the originating MUA to request that
   the originating MUA be explicitly notified when a submitted military
   message has been successfully delivered to a recipient MUA.  This
   notification is convered by a delivery report.  The delivery report
   is related to the submitted mesages by means of a message identifier



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   and includes the date and time of delivery.  Receipt of a delivery
   report at the originating MUA results in the the generation of a
   delivery notification to the originator.  In the case of multi-
   destination military messages, this service shall be selectable on a
   per recipient basis.

   This element of service MUST be supported using the NOTIFY parameter
   of the ESMTP RCPT command with as value of SUCCESS, as defined in
   [RFC3461].

   Note that while this element of service is selectable on a per
   recipient basis, an MUA MAY only allow it to be selected on a per
   message basis.

3.4.13.  Designation of Recipient by Directory Name

   This element of service enables an originating UA to use, on a per-
   recipient basis, a directory name in place of an individual
   recipient's address.  This implies the support of a directory
   service.  The directory name must be translated to an email address
   for delivery to take place.  However, the directory lookup may take
   place at the MTA rather than at the MUA.

   Designation of Recipient by Directory Name is not suppoted by this
   profile.

   However the designation of a recipient by a directory name MAY be
   supported by a MUA that can retrieve an address from a directory
   service.

3.4.14.  Disclosure of Other Recipients

   This element of service enables the originating MTA to instruct the
   MTS to disclose the address of all other recipient of a multi-
   recipient military message to each recipient MUA, upon delivery of
   the message.  The addresses disclosed are as supplied by the
   originating MUA or the results of address list expansion.

   Disclosure of Other Recipients is not supported by this profile.

3.4.15.  DL Expansion History Indication

   This element of service provides information to a recipient about the
   DL(s) that resulted in the message being delivered to this recipient.
   This element of service also provides a mechanism to protect against
   potential nested DL looping.

   [[What are we going to do here?]]



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   The DL-Expansion-History header defined in [RFC2156] SHALL NOT be
   used.  DL-Expansion-History header MAY be present in messages
   gatewayed from X.400.

3.4.16.  DL Expansion Prohibited

   This element of service allows an originating user to specify that if
   any of the recipient names can directly, or be reassignment, refer to
   a distribution, then no expansion of the distribution shall occur.
   Instead, a non-delivery notification shall be returned to the
   originating Mail User Agent.

   [[What are we going to do here?]]

3.4.17.  Expiry Date Indication

   This element of service allows the originator to indicate to the
   recipient the date and time after which the message is considered
   invalid.  The intent of this element of service is to state the
   originator's assessment of the current applicability of a message.
   If the Expiry Date Indication is present, it shall be displayed to
   the recipients(s) to indicate the time after which this message
   should be longer be acted upon.  It is left to the discretion of the
   recipient as to whether or not the message is discarded.

   The Expiry Date Indication element of service, if supported by the
   MMHS, SHALL use the Expires header field, as defined in [RFC2156]

3.4.18.  Explicit Conversion

   This element of service enables an originating MUA to request, on a
   per-recipient basis, that the MTA perform a specified Encoded
   Information Type conversion.

   Explicit Conversion is not supported by this profile.

3.4.19.  Forwarded MM Indication

   This element of service allows an message, plus its delivery
   information to be sent as a body part inside another message.  In a
   multi-part body the forwarded message may be one of serveral body
   parts of various types.

   The Forwarded MM Indication element of service, if supported by the
   MMHS, SHALL use the Content Type header field, as defined in
   [RFC2045] with the value "message/rfc822" and use the Content Type
   Indication, as defined in Section 3.3.2, within the headers of the
   embedded message.



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3.4.20.  Grade of Delivery Selection

3.4.21.  Hold for Delivery

   This element of service enables a recipient MUA to request that the
   MTA hold its MMHS messages and returning notifications for delivery
   until a later time.  The MUA can indicate to the MTA when it is
   unavailable to take delivery of messages and notifications, and also,
   when it is again ready to accept delivery of messages and
   notifications from the MTA.  The MTA can indicate to the MUA that
   messages are waiting due to the criteria the MUA established for
   holding messages.  The MMHS message will be held until the maximum
   delivery time for that MMHS message expires, unless the recipient
   releases the hold prior to its expiry.

   There is no current SMTP service that supports the Hold for Delivery
   element of service.  Therefore this profile does not support this
   element of service.

   However, this element of service MAY be partially supported by MTA
   products that provide proprietary mechanisms to schedule delivery
   times based on MMHS message size and MMHS message priority.

3.4.22.  Incomplete Copy Indication

   This element of service allows an originator to indicate that this
   MMHS message is an incomplete copy of a MMHS message with the same
   Message-ID header field in that one or more body parts or header
   fields of the original MMHS message are absent.

   The Incomplete Copy Indication element of service MAY be supported by
   the MMHS, using the Incomplete-Copy header field, as defined in
   [RFC2156].

3.4.23.  Language Indication

   This element of service enables an originating MUA to indicate the
   language type(s) of a submitted message.

   The Language Indication element of service MAY be supported by the
   MMHS, using the Content-Language header field, as defined in
   [RFC3282].









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3.4.24.  Latest Delivery Designation

   This element of service enables an originating MUA to specify the
   latest time by which the MMHS message is to be delivered.  If the MTA
   cannot deliver by the time specified, the MMHS message is canceled
   and a non-delivery report returned to the originating MUA.

   The Latest Delivery Designation element of service MUST be supported
   by the MMHS as defined in the Deliver By SMTP extension [RFC2852].

3.4.25.  Multi-destination Delivery

3.4.26.  Multi-part Body

3.4.27.  Non-receipt Notification Request Indication

   This element of service allows the originator to ask, on a per-
   recipient basis, for notification if the MMHS message is deemed
   unreceivable by any of the recipients.

   The Non-Receipt Notification Request Indication MUST be supported by
   the MMHS, using the Disposition-Notification-To header field as
   defined in [RFC3798].

   In the case where the Non-Receipt Notification Request Indication
   element of service is required for a subset of the recipients the MSA
   MUST: submit a MMHS message to those recipients that a non-receipt
   notification is requested with a Disposition-Notification-To header
   field; and, submit a MMHS message(s) to those recipients that a non-
   receipt notification is not requested without a Disposition-
   Notification-To header field.

   Note that while this element of service is selectable on a per
   recipient basis, an MUA MAY only allow it to be selected on a per
   message basis.

   Note that this element of service will be supported in conjunction
   with the Receipt Notification Request Indication as profiled in
   Section 3.4.33.

3.4.28.  Obsoleting Indication

   This element of service allows the originator to indicate to the
   recipient that one or more previously sent MMHS messages are
   obsolete.  The intention of this element of service is for the MUA to
   display to the user reading the original MMHS message that the
   original MMHS message is obsolete.  It is the responsibility of the
   user for discarding the original MMHS message.



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   The Obsoleting Indication element of service MAY be supported by the
   MMHS, using the Supersedes header field, as defined in [RFC2156].

3.4.29.  Originator Indication

   The Originator Indication MUST use the From header field, as defined
   in [RFC5322], when the Authorizing Users Indication is present in the
   message, and the Sender header field, as defined in [RFC5322], when
   the Authorsing Users Indication is not present in the message.  This
   conditional use of different header fields is required to support
   interoperability with [ACP123] and [STANAG-4406] X.400 systems that
   utilise a MIXER compliant gateway, [RFC2156].

3.4.30.  Originator Requested Alternate Recipient

   This element of service enables the originating MUA to specify, for
   each intended recipient, one alternate recipient to whom the MTA can
   deliver the message, if delivery to the intended recipient is not
   possible.  This service allows a MMHS message that would otherwise be
   delayed or non-delivered to be delivered to an alternative message
   recipient.

   There is no current SMTP service that supports the Originator
   Requested Alternate Recipient element of service.  Therefore this
   profile does not support this element of service.  Note that some
   MTAs may provide propriertary mechanisms that support this element of
   service.

3.4.31.  Prevention of Non-delivery Notification

   This element of service enables an originating MUA to instruct a MTA
   not to return a non-delivery report to the originating MUA in the
   event that the message being submitted is judged undeliverable.

   This element of service MUST be supported by the MMHS, using the
   NOTIFY parameter of the ESMTP RCPT command with as value of NEVER, as
   defined in [RFC3461].

   Note that while this element of service is selectable on a per
   recipient basis, an MUA MAY only allow it to be selected on a per
   message basis.

3.4.32.  Primary and Copy Recipients Indication








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   Primary and Copy recipients, within the MMHS, are known as action and
   information addressees, respectively.  A primary recipient has a
   responsibility to act upon a delivered MMHS message, whereas a Copy
   recipient has been sent the MMHS message for information purposes
   only.

   The Primary and Copy Recipients Indication element of service MUST be
   supported by the MMHS, using the To and Cc header fields,
   respectively, as defined in [RFC5322].

3.4.33.  Receipt Notification Request Indication

   This element of service allows the originator of a MMHS message to
   request, on a per-recipient basis, for notification when a particular
   MMHS message is received.  The recipient MUA MUST prominently display
   the request for this element of service and permit the recipient to
   honour the request or reject the request.

   The Receipt Notification Request Indication MUST be supported by the
   MMHS, using the Disposition-Notification-To header field as defined
   in [RFC3798].

   In the case where the Receipt Notification Request Indication element
   of service is required for a subset of the recipients the MSA MUST:
   submit a MMHS message to those recipients that a receipt notification
   is requested with a Disposition-Notification-To header field; and,
   submit a MMHS message(s) to those recipients that a receipt
   notification is not requested without a Disposition-Notification-To
   header field.

   Note that while this element of service is selectable on a per
   recipient basis, an MUA MAY only allow it to be selected on a per
   message basis.

   Note that this element of service will be supported in conjunction
   with the Receipt Notification Request Indication as profiled in
   Section 3.4.27.

   In the case where the MMHS supports S/MIME security services profiled
   in Section 4 the originating MUA MAY use the Non-repudiation of
   Receipt element of service as specified in Section 4.1.7.

3.4.34.  Redirection Disallowed by Originator

   This element of service enables an originating MUA to instruct the
   MTA that redirection should not be applied to a particular submitted
   MMHS message.




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   There is currently no SMTP service that supports this element of
   service.  Therefore, the Redirection Disallowed by Originator element
   of service is not supported by this profile.

3.4.35.  Redirection of Incoming Messages

   This element of service enables a MUA to instruct the MTA to redirect
   incoming MMHS messages addressed to it, to another MUA or to an
   Address List (AL), for a specified period of time, or until revoked.

   There is currently no SMTP service that supports this element of
   service.  Therefore the Redirection of Incoming Messages element of
   service is not supported by this profile.  However, note that some
   MTA/MDA products MAY be able to enforce a local security policy
   supporting this element of service with proprietary mechanisms.

3.4.36.  Reply Request Indication

   This element of service allows the originator to request, on a per-
   recipient basis, that a recipient send a message in reply to the MMHS
   message that carries the request.  The originator can also optionally
   specify the date by which any reply should be sent and the names of
   one or more users and ALs who the originator requests be included
   among the preferred recipients of any reply.

   The Reply Request Indication element of service is not supported by
   this profile.

   This element of service MAY be procedurally defined by a MMHS.  Hence
   the Reply Request Indication MAY be supported by including the
   request within the body of the MMHS message.

   Blind Copy recipients of the MMHS message, that includes support for
   this element of service within the message body, SHOULD be careful to
   consider the recipients of the reply MMHS message honoring the Blind
   Copy Recipient Indication element of service profiled in
   Section 3.4.5.

3.4.37.  Replying MM Indication

   This element of service allows the originator of a MMHS message to
   indicate to the recipients that the message is being sent in reply to
   another MMHS message.

   The Replying MM Indication element of service MAY be supported by the
   MMHS, using the In-Reply-To header field as defined in [RFC5322].





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3.4.38.  Requested Preferred Delivery Method

   This element of service allows an originator to request, on a per-
   recipient basis, the preference of method or methods of delivery.

   Requested Preferred Delivery Method is not supported by this profile.

3.4.39.  Subject Indication

   This element of service allows the originator to indicate to the
   recipient(s) a user specified short description of the message.

   The Subject Indication element of service MUST be supported by the
   MMHS, using the Subject header field as defined in [RFC5322].

3.4.40.  Use of Distribution List

3.5.  Military Elements of Service

   This section profiles the MMHS Header Fields for use in the MMHS as
   specified in [RFC6477].

3.5.1.  Primary Precedence

   The MMHS-Primary-Precedence header field defined in [RFC6477] MUST be
   supported by the MMHS if the military message contains "To:"
   ("action") addresses.

3.5.2.  Copy Precedence

   The MMHS-Copy-Precedence header field defined in [RFC6477] MUST be
   supported by the MMHS if the military message contains "Cc:" or
   "Bcc:" ("information") addresses.

3.5.3.  Message Type

   The MMHS-Message-Type header field defined in [RFC6477] MUST be
   supported by the MMHS.

3.5.4.  Exempted Addresses

   The MMHS-Exempted-Address header field defined in [RFC6477] MAY be
   supported by the MMHS.

3.5.5.  Extended Authorization Info

   The MMHS-Extended-Authorisation-Info header field defined in
   [RFC6477] MUST be supported by the MMHS.



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3.5.6.  Distribution Code

   The MMHS-Subject-Indicator-Codes header field defined in [RFC6477]
   MUST be supported by the MMHS.

3.5.7.  Message Instructions

   The MMHS-Message-Instructions header field defined in [RFC6477] MAY
   be supported by the MMHS.

3.5.8.  Clear Service

   This element of service indicates to the recipient that the military
   message containing classified information has been transmitted over
   non-secure communications links.  This element of service, if
   permitted by the security policy, MAY be supported by using the
   printable string "CLEAR" in the privacy mark component of the
   security label (see Section 4.1.6) along with an appropriate security
   policy identifier.  If this element of service is supported by the
   MMHS, the MUA MUST prominently display to the user that the military
   message has been transmitted over non-secure communication links.

3.5.9.  Other Recipient Indicator

   The MMHS-Other-Recipients-Indicator-To and MMHS-Other-Recipients-
   Indicator-CC header fields defined in [RFC6477] MAY be supported by
   the MMHS.

3.5.10.  Originator Reference

   The MMHS-Originator-Reference header field defined in [RFC6477] MAY
   be supported by the MMHS.

3.5.11.  Use of Address List

   The Address List Indication element of service is not supported by
   this profile.

3.6.  Transition Elements of Service

3.6.1.  Handling Instructions

   The MMHS-Handling-Instructions header field defined in [RFC6477] MAY
   be supported by the MMHS only to support interoperability with ACP
   127 systems.

3.6.2.  Pilot Forwarded




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   The Pilot Forwarded element of service is not supported by this
   profile.

3.6.3.  Corrections

   The Corrections element of service MAY be supported by this profile.
   [[Define new MIME type?]]

3.6.4.  ACP 127 Message Identifier

   The MMHS-Acp127-Message-Identifier header field defined in [RFC6477]
   MAY be supported by the MMHS only to support interoperability with
   ACP 127 systems.

3.6.5.  Originator PLAD

   The MMHS-Originator-PLAD header field defined in [RFC6477] MAY be
   supported by the MMHS only to support interoperability with ACP 127
   systems.

3.6.6.  Codress Message Indicator

   The MMHS-Codress-Message-Indicator header field defined in [RFC6477]
   MAY be supported by the MMHS only to support interoperability with
   ACP 127 systems.

3.6.7.  ACP 127 Notification Request

   The ACP 127 Notification Request element of service is not supported
   by this profile.

3.6.8.  ACP 127 Notification Response

   The ACP 127 Notification Response element of service is not supported
   by this profile.

4.  Security Services

   An MMHS MAY support security services.  The security services
   specified in this profile are based on the Secure Multipurpose
   Internet Mail Extensions (S/MIME) protocols and DomainKeys Identified
   Mail (DKIM) Signatures specified in [RFC6376].  The S/MIME protocols
   Message Specification [RFC5751], Cryptographic Message Syntax
   [RFC5652] and Enhanced Security Services for S/MIME [RFC2634] specify
   a consistent way to securely send and receive MIME messages providing
   end to end integrity, authentication, non-repudiation and
   confidentiality.  DKIM's primary purpose is to define an
   organization-level digital signature authentication framework for



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   Internet email, using public key cryptography and using the domain
   name service as its key server technology.  However, it is possible
   to administer DKIM to support user-level signature granularity.  This
   section describes the elements of service and profiles the use of
   [RFC5751], [RFC5652], [RFC2634] and [RFC6376].

4.1.  Elements of Service

   The security services and the implementation requirements to ensure
   interoperability of the security solution for the MMHS are detailed
   below.

4.1.1.  Access Control

   This element of service provides a means of enforcing the
   authorization of users to originate and receive messages.  Access
   controls are performed in each MMHS domain in accordance with the
   security policy in force.  MMHS systems MAY enforce their own native
   security policies, plus any other security policies that have been
   bilaterally agreed.

   An MMHS providing the access control element of service MUST perform
   access control decisions based on comparing the sensitivity
   information conveyed in a security label with a user's
   authorizations.

4.1.2.  Authentication of Origin

   This element of service provides assurance that the message was
   originated by the user indicated as the sender by digitally signing
   the message.  However, it must be noted that the implementation of
   the MMHS security services is dependent upon the security and
   assurance requirements that are to be met by those MMHS security
   services.  As such, the identity of the signer of the MMHS message
   may be the user, the role the user is performing or the organization
   the user belongs to.

   If the MMHS provides security services it MUST support the
   Authentication of Origin element of service.

   The MMHS SHOULD implement this element of service on origination
   supporting the SignedData content type (profiled in Section 4.2.1.2)
   to apply a digital signature to a MMHS message or, in a degenerate
   case where there is no signature information, to convey certificates.

   Alternatively the MMHS MAY implement this element of service on
   origination supporting DKIM (profiled in Section 4.2.3) to apply a
   digital signature to a MMHS message.



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   On reception the MMHS MUST support S/MIME and DKIM digital
   signatures.

4.1.3.  Non-repudiation of Origin

   This element of service provides the recipient with evidence that
   demonstrates, to a third-party, who originated the message, and will
   protect against any attempt by the message originator to falsely deny
   having sent the message.  However, it must be noted that the
   implementation of the MMHS security services is dependent upon the
   security and assurance requirements that are to be met by those MMHS
   security services.  As such, the identity of the signer of the MMHS
   message may be the user, the role the user is performing or the
   organization the user belongs to.

   If the MMHS provides security services it MUST support the Non-
   repudiation of Origin element of service.

   The MMHS SHOULD implement this element of service on origination as
   profiled in Section 4.2.1.2.

   Alternatively the MMHS MAY implement this element of service on
   origination supporting DKIM (profiled in Section 4.2.3) to apply a
   digital signature to a MMHS message.

   On reception the MMHS MUST support S/MIME and DKIM digital
   signatures.

4.1.4.  Message Integrity

   This element of service provides a method of ensuring the content
   that was received by the recipient(s) is the same as that which was
   sent by the originator.  However, it must be noted that the
   implementation of the MMHS security services is dependent upon the
   security and assurance requirements that are to be met by those MMHS
   security services.  As such, the identity of the signer of the MMHS
   message may be the user, the role the user is performing or the
   organization the user belongs to.

   If the MMHS provides security services it MUST support the Message
   Integrity element of service.

   The MMHS SHOULD implement this element of service on origination as
   profiled in Section 4.2.1.2.

   Alternatively the MMHS MAY implement this element of service on
   origination supporting DKIM (profiled in Section 4.2.3) to apply a
   digital signature to a MMHS message.



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   On reception the MMHS MUST support S/MIME and DKIM digital
   signatures.

4.1.5.  Message Data Separation

   This element of service protects against unauthorized disclosure of
   the message, and separates data contained in one message from that
   contained in another message.  This element of service can help to
   enforce need to know restrictions, or enables multiple different user
   communities to share the same secure network.  The service is
   independent of the network and systems transporting the message.

   The MMHS MAY implement this element of service supporting the
   EnvelopedData content type (profiled in Section 4.2.1.3) to apply
   privacy protection to a message.  A sender needs to have access to a
   public key for each intended message recipient to use this service.
   This content type does not provide authentication.

4.1.6.  Security Labels

   This element of service provides a method for associating security
   labels with objects in the MMHS.  This then allows a security policy
   to define what entities can handle messages containing associated
   security labels.  The security label associated with a message MUST
   indicate the security policy to be followed along with the
   sensitivity, compartments, and other handling caveats associated with
   the message.  This element of service can be used for purposes such
   as access control or a source of routing information.

   If the MMHS supports security services then the MMHS MUST implement
   this element of service as profiled in Section 4.2.4.

4.1.7.  Non-repudiation of Receipt

   This element of service provides the originator with evidence that
   demonstrates, to a third-party, who received the message, and will
   protect against any attempt by the message recipient to falsely deny
   having received the message.  This evidence is the signed receipt,
   which includes a digital signature and the certificates necessary to
   verify it.

   The MMHS MAY implement this element of service supporting the
   ReceiptRequest attribute as specified in [RFC2634] Section 2.

4.1.8.  Secure Mailing Lists

   This element of service allows a Mail List Agent (MLA) to take a
   single message, perform recipient-specific security processing, and



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   then redistributes the message to each member of the Address List
   (AL) or Mail List (ML).

   The MMHS MAY implement this element of service supporting the
   mlExpansionHistory attribute as specified in [RFC2634] Section 4.

4.1.9.  Message Counter Signature

   This element of service allows multiple signatures to be applied to
   the original signature value in a sequential manner.  Thus, the
   Message Counter-signature service allows supervising users or release
   authorities to countersign for an originator without invalidating the
   original signature.

   The MMHS MAY implement this element of service supporting the
   countersignature attribute as specified in [RFC5652] Section 11.4.

4.1.10.  Certificate Binding

   This element of service allows for a certificate, which is sent with
   the message to be cryptographically bound to the message.

   The MMHS MAY implement this element of service supporting the
   SigningCertificate attribute as specified in [RFC2634] Section 5.
   The SigningCertificate attribute SHOULD only contain the leaf end-
   user certificate except where some prior agreement (possibly
   bilateral) exists to ensure that path validation is not adversely
   affected.  Differing treatment in [RFC2634] Section 5.3, paragraph 3
   avoids impact to path validation if only the leaf certificate is
   included.

4.1.11.  Compressed Data

   This element of service reduces message size, which helps to protect
   MMHS availability and may provide an element of robustness in the
   event of denial of service attacks.

   If the MMHS provides security services it MUST support the Compressed
   Data element of service.

   The MMHS SHOULD include support for the Compressed Data content type
   on origination as profiled in Section 4.2.1.4.

   Alternatively the MMHS MAY support the application/zlib and
   application/gzip MIME media types on origination as defined in
   [RFC6713].





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   On reception the MMHS MUST support the Compressed Data content type,
   application/zlib media type and application/gzip media type.

4.2.  Security Profile

   This section profiles the use of the S/MIME protocols [RFC5751],
   [RFC5652] and [RFC2634] and DKIM protocol [RFC6376] for adding
   cryptographic services to the MMHS.  The relevant sections of
   [RFC5751], [RFC5652], [RFC2634] and [RFC6376] are listed with further
   clarifications and amendments specific to the implementation of an
   MMHS conformant with this security profile.

   This security profile is aligned with the "Profile for the Use of the
   Cryptographic Message Syntax FO(CMS) and Enhanced Security Services
   (ESS) for S/MIME", [STANAG-4631].

4.2.1.  S/MIME Cryptographic Message Syntax Content Types

   If the MMHS supports the S/MIME protocols for implementing the
   security elements of services then the MMHS MUST support the Data,
   SignedData, EnvelopedData, and CompressedData content types as
   specified in [RFC5751].

   In accordance with [RFC5652] ContentInfo MUST be supported to
   encapsulate the outer most SignedData or EnvelopedData content type.
   Conventions for inner wrappers MUST comply with [RFC5751].

   The clarifications and refinements are as follows:

   o  The ContentInfo contentType field MUST be supported.

   o  The ContentInfo content field MUST be supported.

4.2.1.1.  Data Content Type

   The MMHS MUST use the id-data content type identifier to identify the
   "inner" MIME message content as specified in [RFC5751].

4.2.1.2.  Signed-data Content Type

   The signedData content type is specified in [RFC5652] Section 5,
   consisting of MIME content (identified by the id-data content type)
   and zero or more signature values.

4.2.1.2.1.  SignedData Type

   The MMHS MUST support the SignedData type as specified in [RFC5652]
   Section 5.1.  The clarifications and refinements are as follows:



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   o  The MMHS MUST support the EncapsulatedContentInfo type
      eContentType attribute.  The value of the eContentType MUST be id-
      data unless the content is compressed according to
      Section 4.2.1.4.

   o  The MMHS MUST support the EncapsulatedContentInfo type eContent
      attribute.  The value of the eContent MUST contain the content to
      be signed.  If the content is compressed using the compressed-data
      content type as defined in Section 4.2.1.4, the
      CompressedData.encapContentInfo.eContentType MUST be set to the
      id-data content type identifier of the compressed MIME content and
      the CompressedData.encapContentInfo.eContent MUST contain the MIME
      content to be compressed and protected by S/MIME.

   o  The MMHS MUST support X.509 version 3 certificates.  An MMHS with
      high throughput MUST include certificates within the message.  An
      MMHS with impoverished communications SHOULD NOT send certificates
      with the message.

   o  The MMHS MUST support the certificate profile and CRL profile
      specified in [RFC5280] [RFC6818].

   o  The MMHS MUST support X.509 version 3 certificate processing
      specified in [RFC5750].

4.2.1.2.2.  SignerInfo Type

   The SignerInfo type is specified in [RFC5652] Section 5.3 allowing
   the inclusion of unsigned and signed attributes along with a
   signature.  The clarifications and refinements are as follows:

   o  The MMHS MUST support signed attributes.  As a minimum the MMHS
      MUST support processing and handling of the following signed
      attributes: contentType ([RFC5751] Section 2.5.1);
      eSSSecurityLabel ([RFC2634] Section 3.2; messageDigest ([RFC5652]
      Section 11.2); signingTime ([RFC5751] Section 2.5.1);
      sMIMECapabilities ([RFC5751] Section 2.5.2); and,
      sMIMEEncryptionKeyPreference ([RFC5751] Section 2.5.3).

   o  The MMHS MUST support the conventions for using the Secure Hash
      Algorithm (SHA) message digest algorithms and signature algorithms
      as specified in [RFC5754] and [RFC5751].

   o  The MMHS MUST support both the SignerIdentifier type attributes
      issuerAndSerialNumber and subjectKeyIdentifier.

4.2.1.3.  Enveloped-data Content Type




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   The envelopedData content type is specified in [RFC5652] Section 6,
   consisting of an encrypted MIME content (identified by the id-data
   content type) and encrypted content-encryption keys for one or more
   recipients.

4.2.1.3.1.  EnvelopedData Type

   The MMHS MUST support the EnvelopedData type as specified in
   [RFC5652] Section 6.1.  The clarifications and refinements are as
   follows:

   o  The MMHS MUST support the EncryptedContentInfo type eContentType
      attribute.  The value of the eContentType MUST be id-data unless
      the content is compressed according to Section 4.2.1.4.

   o  The MMHS MUST support the EncryptedContentInfo type eContent
      attribute.  The value of the eContent MUST contain the content to
      be encrypted.  If the content is compressed using the compressed-
      data content type as defined in Section 4.2.1.4, the
      CompressedData.encapContentInfo.eContentType MUST be set to the
      id-data content type identifier of the compressed MIME content and
      the CompressedData.encapContentInfo.eContent MUST contain the MIME
      content to be compressed and protected by S/MIME.

   o  The MMHS MUST support the originatorInfo attribute if required by
      the key-management algorithm (refer to Section 4.2.1.3.1.1).

   o  The MMHS MUST support X.509 version 3 certificates.  An MMHS with
      high throughput MUST include certificates within the message.  An
      MMHS with impoverished communications SHOULD NOT send certificates
      with the message.

   o  The MMHS MUST support the certificate profile and CRL profile
      specified in [RFC5280] [RFC6818].

   o  The MMHS MUST support X.509 version 3 certificate processing
      specified in [RFC5750].

4.2.1.3.1.1.  RecipientInfo Type

   The RecipientInfo type is specified in [RFC5652] Section 6.2.  The
   clarifications and refinements are as follows:

   o  The MMHS MAY support KeyTransRecipientInfo.

   o  The MMHS MUST support KeyAgreeRecipientInfo.  The originatorKey
      attribute MUST be supported as the choice for the originator to
      specify the sender's key agreement public key.



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   o  The MMHS MAY support KEKRecipientInfo.

   o  The MMHS MAY support PasswordRecipientinfo.

   o  The MMHS MAY support OtherRecipientInfo.

4.2.1.4.  Compressed-Data Content Type

   The MMHS MUST support the compressedData content type as specified in
   [RFC3274].

4.2.1.4.1.  CompressedData Type

   In the cases where the MMHS uses compressedData, it MUST only be used
   once for every message and MUST only be used around the content of
   the innermost security wrapper.

4.2.2.  S/MIME Triple Wrapping

   If the MMHS supports S/MIME protocols for providing the security
   elements of services (defined in this profile) the MMHS MUST support
   military messages that are triple wrapped or signed only.  A triple
   wrapped message is one that has been signed, then encrypted, then
   signed again.  The signers of the inner and outer signatures may be
   different entities or the same entity.  If a military message is
   triple wrapped, the SignedData and EnvelopedData wrappers MUST follow
   the specifications described in Section 4.2.1.2 and Section 4.2.1.3
   of this profile, respectively.

4.2.3.  DKIM Digital Signatures

   DKIM defines an organization-level digital signature authentication
   framework for Internet email, using public key cryptography and using
   the domain name service as its key server technology.  However, it is
   possible to administer DKIM to support user-level signature
   granularity.  This profile specifies the use of DKIM defined in
   [RFC6376] for providing an alternative security mechanism to S/MIME
   to deliver the mandatory security elements of service to the MMHS.
   However, the implementation of DKIM is dependent upon the security
   and assurance requirements that are to be met by the MMHS security
   services.  As such, an MMHS MUST implement DKIM (to apply digital
   signatures for the MMHS message header fields and message body) to
   meet those security and assurance requirements based on one of the
   following profiles:

   1.  Share the organization signing identity (identified by the
       Signing Domain Identifier (SDID)) private key for signing the
       MMHS message header fields.  The MMHS message header fields are



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       digitally signed by the organization MSA component.  This profile
       does not provide end to end security services.  This profile
       supports organization to organization message integrity,
       authentication and non-repudiation security services.

   2.  Share the organization signing identity private key for signing
       the MMHS message header fields.  The email address of the MMHS
       message originator can be specified as the Agent or User
       Identifier (AUID).  The semantics for performing per-user
       identity differentiation with this approach MUST be agreed out-
       of-band and is outside the scope of this profile.  The MMHS
       message header fields are digitally signed by the organization
       MSA component.  This profile does not provide end to end security
       services.  This profile supports organization to organization
       message integrity, authentication and non-repudiation security
       services.

   3.  Generate per-user public/private key pairs where the public key
       is published to distinct subdomains (of the organization domain).
       The MMHS message is signed with the user's private key and the
       signing identity is identifiable by the user's subdomain value in
       the SDID.  The MMHS message header fields are digitally signed by
       the MUA.  This profile supports end to end originator
       authentication, message integrity, and non-repudiation security
       services.

   4.  Generate per-user public/private key pairs where the public key
       is published to a unique resource record under the organization
       domain.  The MMHS message is signed with the user's private key
       and the signing identity is identifiable by the domain value in
       the SDID and the unique resource record identified by the
       selector value.  The MMHS message header fields are digitally
       signed by the MUA.  This profile supports end to end originator
       authentication, message integrity, and non-repudiation security
       services.

   To provide organization to organization security services: the
   recipient MUA SHOULD support DKIM digital signature verification or
   the MUA MUST support the Authentication-Results header field as
   specified in [RFC5451] according to the security policy; and the
   organization border MTA or MDA MUST support DKIM digital signature
   verfication and output the verification results (according to the
   security policy) to the Authentication-Results header field compliant
   with [RFC5451].

   To provide end to end security services the recipient MUA MUST
   support DKIM digital signature verification specified in [RFC6376].




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   DKIM does not provide confidentiality security services.

4.2.4.  Security Labels

   If the MMHS supports S/MIME protocols for implementing security
   services then the MMHS MUST support on origination the
   ESSSecurityLabel specified in Section 3 of [RFC2634].  The MMHS MUST
   support the security-policy-identifier, security-classification,
   privacy-mark and security-categories attributes of the
   ESSSecurityLabel.  The MMHS MAY support the Equivalent Security
   Labels EquivalentLabels as specified in [RFC2634] Section 3.4.

   An MMHS MAY on origination support the SIO-Label header field as
   specified in [[i-d ref]].

   On reception the MMHS MUST support the ESSSecurityLabel and SIO-
   Label.  In the case where a military message contains a SIO-Label and
   an ESSSecurityLabel the MMHS MUST assert that the policy conveyed in
   both are the same and that the sensitivity, compartments, and other
   handling caveats that can be conveyed in both are the same.

4.2.5.  Message Header Fields

   By default, [RFC5751] secures MIME message body parts, excluding the
   message header fields.  If the MMHS implements S/MIME security
   services then the MMHS MUST provide a mechanism for securing the
   message header fields.  [RFC5751] includes a mechanism for protecting
   the header fields where the whole message is wrapped in a message/
   rfc822 MIME media type.  However, this approach can be problematic
   for non-S/MIME aware MUAs and does not provide a mechanism for
   signing a subset of message header fields.

   If the MMHS provides security services this profile requires that the
   MMHS MUST support DomainKeys Identified Mail (DKIM) Signatures
   profiled in Section 4.2.3 for digitally signing the MMHS message
   header fields.

   The MMHS MUST include at least the following header fields to be
   signed:

   o  From

   o  Reply-To

   o  Subject

   o  Date




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   o  To, Cc, Bcc (if present)

   o  Expires

   o  Message-ID

   o  SIO-Label (if present)

   o  MMHS-Primary-Precedence (if present), MMHS-Copy-Precedence (if
      present), MMHS-Message-Type, MMHS-Extended-Authorisation-Info

   DKIM does not provide confidentiality security services.

5.  Requirements on Mail User Agents

5.1.  Standards Compliance

   A Mail User Agent (MUA) compliant with this specification MUST
   support

   1.  Internet Message Format [RFC5322].

   2.  Multipurpose Internet Mail Extensions (MIME) [RFC2045] [RFC2046]
       [RFC2047] [RFC2049].  [[Maybe be a bit more specific about what
       is required?]]

   3.  Parsing, processing and having the ability to generate MMHS
       header fields [RFC6477].

   4.  The ability to insert MT-Priority header field [RFC6758].

   5.  Parsing and processing of Multipart/Report Content Type for the
       Reporting of Mail System Administrative Messages [RFC6522]
       containing message/delivery-status [RFC3464] and Message
       Disposition Notification (MDN) [RFC3798].

   6.  The ability to request an MDN and the ability to generate an MDN
       in response to a request [RFC3798].

   7.  The ability to send and receive signed and encrypted S/MIME
       messages [RFC5652] [RFC5751].

   8.  The ability to send and receive ESS Security Labels [RFC2634].

   MUA can also take advantage of SMTP extensions advertised by MSAs
   (see Section 6).





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5.2.  Audit Trail and Logging

6.  Requirements on Mail Submission Agents

6.1.  Standards Compliance

   In addition to the list of requirements specified in [RFC6409], an
   Mail Submission Agent (MSA) compliant with this specification MUST
   support:

   1.   SMTP Extension for Authentication [RFC4954].

   2.   SMTP Extension for Secure SMTP over TLS [RFC3207].

   3.   SMTP Service Extension for Returning Enhanced Error Codes
        [RFC2034].

   4.   Deliver By SMTP Service Extension [RFC2852].

   5.   SMTP extension for Message Transfer Priorities.  [RFC6710]
        "STANAG4406" Priority Assignment Policy MUST be advertised in
        the EHLO response.  The MSA MUST be able to handle the MT-
        Priority header field as specified in [RFC6758].

   6.   SMTP extension for for Delivery Status Notifications [RFC3461].

   7.   SMTP Extension for 8-bit MIME transport [RFC6152].

   8.   SMTP Extension for Message Size Declaration [RFC1870].

   9.   SMTP Extension for Command Pipelining [RFC2920].

   10.  SMTP Extensions for Transmission of Large and Binary MIME
        Messages [RFC3030].

   The following SMTP extensions are OPTIONAL to support in MSAs
   compliant with this specification:

   1.  SMTP Submission Service Extension for Future Message Release
       [RFC4865].

6.2.  Audit Trail and Logging









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7.  Requirements on Mail Transfer Agents

7.1.  Standards Compliance

   A Mail Transfer Agent (MTA) compliant with this specification MUST
   support

   1.  SMTP Service Extension for Returning Enhanced Error Codes
       [RFC2034].

   2.  Deliver By SMTP Service Extension [RFC2852].

   3.  SMTP extension for Message Transfer Priorities [RFC6710].
       "STANAG4406" Priority Assignment Policy MUST be advertised in the
       EHLO response.  The MTA MUST be able to handle the MT-Priority
       header field as specified in [RFC6758].

   4.  SMTP extension for for Delivery Status Notifications [RFC3461].

   5.  SMTP Extension for 8-bit MIME transport [RFC6152].

   6.  SMTP Extension for Message Size Declaration [RFC1870].

   7.  SMTP Extension for Command Pipelining [RFC2920].

   8.  SMTP Extensions for Transmission of Large and Binary MIME
       Messages [RFC3030].

   The following SMTP extensions SHOULD be supported in MTAs compliant
   with this specification:

   1.  SMTP Extension for Secure SMTP over TLS [RFC3207].

7.2.  Audit Trail and Logging

8.  IANA Considerations

   This document doesn't ask for any action from IANA.

9.  Security Considerations

   TBD









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10.  References

10.1.  Normative References

   [RFC2033]  Myers, J., "Local Mail Transfer Protocol", RFC 2033,
              October 1996.

   [RFC2034]  Freed, N., "SMTP Service Extension for Returning Enhanced
              Error Codes", RFC 2034, October 1996.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3461]  Moore, K., "Simple Mail Transfer Protocol (SMTP) Service
              Extension for Delivery Status Notifications (DSNs)", RFC
              3461, January 2003.

   [RFC5321]  Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
              October 2008.

   [RFC5322]  Resnick, P., Ed., "Internet Message Format", RFC 5322,
              October 2008.

   [RFC6409]  Gellens, R. and J. Klensin, "Message Submission for Mail",
              STD 72, RFC 6409, November 2011.

   [RFC1870]  Klensin, J., Freed, N., and K. Moore, "SMTP Service
              Extension for Message Size Declaration", STD 10, RFC 1870,
              November 1995.

   [RFC2852]  Newman, D., "Deliver By SMTP Service Extension", RFC 2852,
              June 2000.

   [RFC2920]  Freed, N., "SMTP Service Extension for Command
              Pipelining", STD 60, RFC 2920, September 2000.

   [RFC3030]  Vaudreuil, G., "SMTP Service Extensions for Transmission
              of Large and Binary MIME Messages", RFC 3030, December
              2000.

   [RFC4865]  White, G. and G. Vaudreuil, "SMTP Submission Service
              Extension for Future Message Release", RFC 4865, May 2007.

   [RFC6152]  Klensin, J., Freed, N., Rose, M., and D. Crocker, "SMTP
              Service Extension for 8-bit MIME Transport", STD 71, RFC
              6152, March 2011.





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   [RFC4954]  Siemborski, R. and A. Melnikov, "SMTP Service Extension
              for Authentication", RFC 4954, July 2007.

   [RFC3207]  Hoffman, P., "SMTP Service Extension for Secure SMTP over
              Transport Layer Security", RFC 3207, February 2002.

   [RFC6477]  Melnikov, A. and G. Lunt, "Registration of Military
              Message Handling System (MMHS) Header Fields for Use in
              Internet Mail", RFC 6477, January 2012.

   [RFC6710]  Melnikov, A. and K. Carlberg, "Simple Mail Transfer
              Protocol Extension for Message Transfer Priorities", RFC
              6710, August 2012.

   [RFC6758]  Melnikov, A. and K. Carlberg, "Tunneling of SMTP Message
              Transfer Priorities", RFC 6758, October 2012.

   [RFC2045]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part One: Format of Internet Message
              Bodies", RFC 2045, November 1996.

   [RFC2046]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part Two: Media Types", RFC 2046,
              November 1996.

   [RFC2047]  Moore, K., "MIME (Multipurpose Internet Mail Extensions)
              Part Three: Message Header Extensions for Non-ASCII Text",
              RFC 2047, November 1996.

   [RFC2049]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part Five: Conformance Criteria and
              Examples", RFC 2049, November 1996.

   [RFC6713]  Levine, J., "The 'application/zlib' and 'application/gzip'
              Media Types", RFC 6713, August 2012.

   [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.

   [RFC6818]  Yee, P., "Updates to the Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 6818, January 2013.

   [RFC2634]  Hoffman, P., "Enhanced Security Services for S/MIME", RFC
              2634, June 1999.




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   [RFC5652]  Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
              RFC 5652, September 2009.

   [RFC5751]  Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet
              Mail Extensions (S/MIME) Version 3.2 Message
              Specification", RFC 5751, January 2010.

   [RFC5754]  Turner, S., "Using SHA2 Algorithms with Cryptographic
              Message Syntax", RFC 5754, January 2010.

   [RFC5750]  Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet
              Mail Extensions (S/MIME) Version 3.2 Certificate
              Handling", RFC 5750, January 2010.

   [RFC3274]  Gutmann, P., "Compressed Data Content Type for
              Cryptographic Message Syntax (CMS)", RFC 3274, June 2002.

   [RFC3464]  Moore, K. and G. Vaudreuil, "An Extensible Message Format
              for Delivery Status Notifications", RFC 3464, January
              2003.

   [RFC6522]  Kucherawy, M., "The Multipart/Report Media Type for the
              Reporting of Mail System Administrative Messages", STD 73,
              RFC 6522, January 2012.

   [RFC3798]  Hansen, T. and G. Vaudreuil, "Message Disposition
              Notification", RFC 3798, May 2004.

   [RFC3282]  Alvestrand, H., "Content Language Headers", RFC 3282, May
              2002.

   [RFC5228]  Guenther, P. and T. Showalter, "Sieve: An Email Filtering
              Language", RFC 5228, January 2008.

   [RFC5451]  Kucherawy, M., "Message Header Field for Indicating
              Message Authentication Status", RFC 5451, April 2009.

   [RFC2156]  Kille, S., "MIXER (Mime Internet X.400 Enhanced Relay):
              Mapping between X.400 and RFC 822/MIME", RFC 2156, January
              1998.

   [RFC6376]  Crocker, D., Hansen, T., and M. Kucherawy, "DomainKeys
              Identified Mail (DKIM) Signatures", RFC 6376, September
              2011.

   [ACP123]   CCEB, ., "Common Messaging Strategy and Procedures", ACP
              123, May 2009.




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10.2.  Informative References

   [RFC5598]  Crocker, D., "Internet Mail Architecture", RFC 5598, July
              2009.

   [STANAG-4406]
              NATO, ., "STANAG 4406 Edition 2: Military Message Handling
              System", STANAG 4406, March 2005.

   [STANAG-4631]
              NATO, ., "STANAG 4631 Edition 1: Profile for the Use of
              the Cryptographic Message Syntax FO(CMS) and Enhanced
              Security Services (ESS) for S/MIME", STANAG 4631, June
              2008.

Appendix A.  Acknowledgements

   Many thanks for input provided by Steve Kille and David Wilson.

Authors' Addresses

   Alexey Melnikov
   Isode Ltd
   5 Castle Business Village
   36 Station Road
   Hampton, Middlesex  TW12 2BX
   UK

   EMail: Alexey.Melnikov@isode.com


   Graeme Lunt
   SMHS Ltd
   Bescar Moss Farm
   Bescar Lane
   Ormskirk  L40 9QN
   UK

   EMail: graeme.lunt@smhs.co.uk












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   Alan Ross
   SMHS Ltd
   Bescar Moss Farm
   Bescar Lane
   Ormskirk  L40 9QN
   UK

   EMail: alan.ross@smhs.co.uk











































Melnikov, et al.        Expires December 21, 2013              [Page 48]


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