OpenPGP Message Format
draft-ietf-openpgp-rfc4880bis-04

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Network Working Group                                            W. Koch
Internet-Draft
Updates: 4880 (if approved)                             January 25, 2018
Intended status: Standards Track
Expires: July 29, 2018

                         OpenPGP Message Format
                    draft-ietf-openpgp-rfc4880bis-04

Abstract

   { Work in progress to update the OpenPGP specification from RFC4880 }

   This document is maintained in order to publish all necessary
   information needed to develop interoperable applications based on the
   OpenPGP format.  It is not a step-by-step cookbook for writing an
   application.  It describes only the format and methods needed to
   read, check, generate, and write conforming packets crossing any
   network.  It does not deal with storage and implementation questions.
   It does, however, discuss implementation issues necessary to avoid
   security flaws.

   OpenPGP software uses a combination of strong public-key and
   symmetric cryptography to provide security services for electronic
   communications and data storage.  These services include
   confidentiality, key management, authentication, and digital
   signatures.  This document specifies the message formats used in
   OpenPGP.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on July 29, 2018.

Koch                      Expires July 29, 2018                 [Page 1]
Internet-Draft           OpenPGP Message Format             January 2018

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  {1} Introduction  . . . . . . . . . . . . . . . . . . . . . .   5
     1.1.  {1.1} Terms . . . . . . . . . . . . . . . . . . . . . . .   5
   2.  {2} General functions . . . . . . . . . . . . . . . . . . . .   6
     2.1.  {2.1} Confidentiality via Encryption  . . . . . . . . . .   6
     2.2.  {2.2} Authentication via Digital Signature  . . . . . . .   7
     2.3.  {2.3} Compression . . . . . . . . . . . . . . . . . . . .   8
     2.4.  {2.4} Conversion to Radix-64  . . . . . . . . . . . . . .   8
     2.5.  {2.5} Signature-Only Applications . . . . . . . . . . . .   8
   3.  {3} Data Element Formats  . . . . . . . . . . . . . . . . . .   9
     3.1.  {3.1} Scalar Numbers  . . . . . . . . . . . . . . . . . .   9
     3.2.  {3.2} Multiprecision Integers . . . . . . . . . . . . . .   9
     3.3.  {3.3} Key IDs . . . . . . . . . . . . . . . . . . . . . .  10
     3.4.  {3.4} Text  . . . . . . . . . . . . . . . . . . . . . . .  10
     3.5.  {3.5} Time Fields . . . . . . . . . . . . . . . . . . . .  10
     3.6.  {3.6} Keyrings  . . . . . . . . . . . . . . . . . . . . .  10
     3.7.  {3.7} String-to-Key (S2K) Specifiers  . . . . . . . . . .  10
       3.7.1.  {3.7.1} String-to-Key (S2K) Specifier Types . . . . .  10
       3.7.2.  {3.7.2} String-to-Key Usage . . . . . . . . . . . . .  12
   4.  {4} Packet Syntax . . . . . . . . . . . . . . . . . . . . . .  13
     4.1.  {4.1} Overview  . . . . . . . . . . . . . . . . . . . . .  13
     4.2.  {4.2} Packet Headers  . . . . . . . . . . . . . . . . . .  14
       4.2.1.  {4.2.1} Old Format Packet Lengths . . . . . . . . . .  14
       4.2.2.  {4.2.2} New Format Packet Lengths . . . . . . . . . .  15
       4.2.3.  {4.2.3} Packet Length Examples  . . . . . . . . . . .  16
     4.3.  {4.3} Packet Tags . . . . . . . . . . . . . . . . . . . .  17
   5.  {5} Packet Types  . . . . . . . . . . . . . . . . . . . . . .  17
     5.1.  {5.1} Public-Key Encrypted Session Key Packets (Tag 1)  .  18
     5.2.  {5.2} Signature Packet (Tag 2)  . . . . . . . . . . . . .  19
       5.2.1.  {5.2.1} Signature Types . . . . . . . . . . . . . . .  19
       5.2.2.  {5.2.2} Version 3 Signature Packet Format . . . . . .  22