RFC 1991 (rfc1991) - Page 1 of 21
PGP Message Exchange Formats
Alternative Format: Original Text Document
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
