OpenPGP Message Format
draft-ietf-openpgp-rfc4880bis-08

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Network Working Group                                            W. Koch
Internet-Draft                                                GnuPG e.V.
Obsoletes: 4880, 5581, 6637 (if                               B. Carlson
           approved)
Intended status: Standards Track                                  R. Tse
Expires: March 9, 2020                                            Ribose
                                                               D. Atkins

                                                              D. Gillmor

                                                       September 6, 2019

                         OpenPGP Message Format
                    draft-ietf-openpgp-rfc4880bis-08

Abstract

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

   This document specifies the message formats used in OpenPGP.  OpenPGP
   provides encryption with public-key or symmetric cryptographic
   algorithms, digital signatures, compression and key management.

   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.

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."

Koch, et al.              Expires March 9, 2020                 [Page 1]
Internet-Draft           OpenPGP Message Format           September 2019

   This Internet-Draft will expire on March 9, 2020.

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