pretty Easy privacy (pEp): Progressive Header Disclosure
draft-luck-lamps-pep-header-protection-03

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Last updated 2019-07-05
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Network Working Group                                            C. Luck
Internet-Draft                                            pEp Foundation
Intended status: Informational                             July 05, 2019
Expires: January 6, 2020

        pretty Easy privacy (pEp): Progressive Header Disclosure
               draft-luck-lamps-pep-header-protection-03

Abstract

   Issues with email header protection in S/MIME have been recently
   raised in the IETF LAMPS Working Group.  The need for amendments to
   the existing specification regarding header protection was expressed.

   The pretty Easy privacy (pEp) implementations currently use a
   mechanism quite similar to the currently standardized message
   wrapping for S/MIME.  The main difference is that pEp is using PGP/
   MIME instead, and adds space for carrying public keys next to the
   protected message.

   In LAMPS, it has been expressed that whatever mechanism will be
   chosen, it should not be limited to S/MIME, but also applicable to
   PGP/MIME.

   This document aims to contribute to this discussion and share the pEp
   implementation experience with email header protection.

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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   Internet-Drafts are draft documents valid for a maximum of six months
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on January 6, 2020.

Luck                     Expires January 6, 2020                [Page 1]
Internet-Draft        Progressive Header Disclosure            July 2019

Copyright Notice

   Copyright (c) 2019 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
   (https://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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   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   4
     1.2.  Terms . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Message Format for Progressive Header Disclosure  . . . . . .   4
     2.1.  Compatibility . . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  Inner Message . . . . . . . . . . . . . . . . . . . . . .   5
     2.3.  Content-Type Parameter "forwarded"  . . . . . . . . . . .   5
     2.4.  Outer Message . . . . . . . . . . . . . . . . . . . . . .   5
     2.5.  Transport Message . . . . . . . . . . . . . . . . . . . .   8
     2.6.  S/MIME Compatibility  . . . . . . . . . . . . . . . . . .   9
   3.  Candidate Header Fields for Header Protection . . . . . . . .   9
   4.  Stub Outside Headers  . . . . . . . . . . . . . . . . . . . .   9
   5.  Processing Incoming Email under Progressive Header Disclosure  10
     5.1.  Processing of Signed-only Email . . . . . . . . . . . . .  10
     5.2.  Incoming Filter Processing  . . . . . . . . . . . . . . .  10
       5.2.1.  Staged Filtering of Inbound Messages  . . . . . . . .  11
     5.3.  Outgoing Filter Processing  . . . . . . . . . . . . . . .  11
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   7.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .  12
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   9.  Implementation Status . . . . . . . . . . . . . . . . . . . .  12
     9.1.  Introduction  . . . . . . . . . . . . . . . . . . . . . .  12
     9.2.  Current software implementing pEp . . . . . . . . . . . .  12
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  13
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  13
     11.2.  Informative References . . . . . . . . . . . . . . . . .  14
   Appendix A.  About pEp Design Principles  . . . . . . . . . . . .  15
   Appendix B.  Document Changelog . . . . . . . . . . . . . . . . .  16
   Appendix C.  Open Issues  . . . . . . . . . . . . . . . . . . . .  17
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  17
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