OpenPGP Message Format

The information below is for an old version of the document that is already published as an RFC
Document Type RFC Internet-Draft (openpgp WG)
Authors Hal Finney  , Lutz Donnerhacke  , Jon Callas  , Rodney Thayer  , David Shaw 
Last updated 2020-01-21 (latest revision 2007-04-25)
Stream Internet Engineering Task Force (IETF)
Formats pdf htmlized (tools) htmlized bibtex
Stream WG state (None)
Document shepherd No shepherd assigned
IESG IESG state RFC 4880 (Proposed Standard)
Consensus Boilerplate Unknown
Telechat date
Responsible AD Sam Hartman
Send notices to <>
Network Working Group                                        Jon Callas
Internet-Draft                                          PGP Corporation
Intended status: Standards Track
Expires October 2007                                   Lutz Donnerhacke
Apr 2007

Obsoletes: 1991, 2440                                        Hal Finney
                                                         PGP Corporation

                                                              David Shaw

                                                           Rodney Thayer

                          OpenPGP Message Format

Status of this Memo

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    have been or will be disclosed, and any of which he or she becomes
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Copyright Notice

    Copyright (C) The IETF Trust (2007).


    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.

Callas, et al.          Expires Oct 24, 2007                   [Page 1]

INTERNET-DRAFT          OpenPGP Message Format             Apr 24, 2007

    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

Callas, et al.          Expires Oct 24, 2007                   [Page 2]

INTERNET-DRAFT          OpenPGP Message Format             Apr 24, 2007

Table of Contents

             Status of this Memo                                       1
             Copyright Notice                                          1
             Abstract                                                  1
             Table of Contents                                         3
    1.       Introduction                                              7
    1.1.     Terms                                                     7
    2.       General functions                                         7
    2.1.     Confidentiality via Encryption                            8
    2.2.     Authentication via Digital signature                      9
    2.3.     Compression                                               9
    2.4.     Conversion to Radix-64                                    9
    2.5.     Signature-Only Applications                              10
    3.       Data Element Formats                                     10
    3.1.     Scalar numbers                                           10
    3.2.     Multiprecision Integers                                  10
    3.3.     Key IDs                                                  11
    3.4.     Text                                                     11
    3.5.     Time fields                                              11
    3.6.     Keyrings                                                 11
    3.7.     String-to-key (S2K) specifiers                           11
    3.7.1.   String-to-key (S2K) specifier types                      11 Simple S2K                                               12 Salted S2K                                               12 Iterated and Salted S2K                                  12
    3.7.2.   String-to-key usage                                      13 Secret key encryption                                    13 Symmetric-key message encryption                         14
    4.       Packet Syntax                                            14
    4.1.     Overview                                                 14
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