RFC 1991 (rfc1991) - Page 1 of 21


PGP Message Exchange Formats



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Network Working Group                                          D. Atkins
Request for Comments: 1991                                           MIT
Category: Informational                                     W. Stallings
                                                    Comp-Comm Consulting
                                                           P. Zimmermann
                                            Boulder Software Engineering
                                                             August 1996


                      PGP Message Exchange Formats

Status of This Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Table of Contents

   1.    Introduction............................................2
   2.    PGP Services............................................2
   2.1   Digital signature.......................................3
   2.2   Confidentiality.........................................3
   2.3   Compression.............................................4
   2.4   Radix-64 conversion.....................................4
   2.4.1 ASCII Armor Formats.....................................5
   3.    Data Element Formats....................................6
   3.1   Byte strings............................................6
   3.2   Whole number fields.....................................7
   3.3   Multiprecision fields...................................7
   3.4   String fields...........................................8
   3.5   Time fields.............................................8
   4.    Common Fields...........................................8
   4.1   Packet structure fields.................................8
   4.2   Number ID fields.......................................10
   4.3   Version fields.........................................10
   5.    Packets................................................10
   5.1   Overview...............................................10
   5.2   General Packet Structure...............................11
   5.2.1 Message component......................................11
   5.2.2 Signature component....................................11
   5.2.3 Session key component..................................11
   6.    PGP Packet Types.......................................12
   6.1   Literal data packets...................................12
   6.2   Signature packets......................................13
   6.2.1 Message-digest-related fields..........................14
   6.2.2 Public-key-related fields..............................15
   6.2.3 RSA signatures.........................................16



Atkins, et. al.              Informational