Pretty Good Privacy version 2.3a - READ ME FIRST Notes by Perry Metzger Edited for 2.3a by Colin Plumb You are looking at the README file for PGP release 2.3a. PGP, short for Pretty Good Privacy, is a public key encryption package; with it, you can secure messages you transmit against unauthorized reading and digitally sign them so that people receiving them can be sure they come from you. The files pgpdoc1.txt and pgpdoc2.txt contain documentation for the system. Before using PGP, PLEASE READ THE DOCUMENTATION. This tends to get neglected with most computer software, but cryptography software is easy to misuse, and if you don't use it properly much of the security you could gain by using it will be lost! Security is only as strong as the weakest link, and while the algorithms in PGP are some of the strongest known in the civilian world, there are things outside the program's control which can weaken your security as assuredly as forgetting to lock a vault door. Even if you are already familiar with public key cryptography, it is important that you understand the various security issues associated with using PGP. PGP 2.3a, released July 2, 1993 fixes some glitches which made their way into PGP 2.3, released June 15, 1993. It will likely be followed by more updated versions in the months to come, so check around for more recent updates, especially if you received PGP 2.3a substantially after the release date. If there is a more recent release, please acquire it, and please get the place from which you got PGP 2.3a or an earlier version to update their release, too. There are four archives in the PGP 2.3a release. You will usually only need one of them. They are: - pgp23A.zip This is the MS-DOS executable release, which includes the executable, support files, and basic documentation. - pgp23srcA.zip This is a source code release, which includes all the source code needed to compile PGP and examples of usage. This contains everything in pgp23A.zip except that the manual is not paginated and it does not contain an executable nor an associated signature. - pgp23A.tar.Z This contains exactly the same files as pgp23srcA.zip, except that they use Unix rather than MS-DOS line end conventions. - pgp23docA.zip This is the documentation for PGP only. This can be freely exported and is useful to tell people what PGP does. While we welcome ports to other platforms, if you make your own archive for distribution, PLEASE INCLUDE THE MANUAL. It covers important security and legal issues which a new user must know. Assuming you have a code (non-documentation) release, the file SETUP.DOC contains information on how to install PGP on your system; this document is broken up into several sections, each dealing with a different operating system: PGP is known to run on MS-DOS, UNIX, VMS and OS/2. Part of the information in SETUP.DOC might make more sense if you have already read the manuals. PGP is distributed under the terms of the GNU General Public Licence, a copy of which is included. In brief, this states that PGP is freely distributable, subject only to the condition that if you make a modified version and choose to distribute it, you must make it freely distributable as well. See the file COPYING for details. This PGP 2.3 release has several bug fixes over PGP 2.2, and a few new (although somewhat esoteric) features. See doc\newfor23.doc for details. The most important fix is to compression on MS-DOS. an invlaid pointer was bring freed, causing unpredictable behaviour. Sometimes, no harm would reault. Sometimes. the machine would crash. MANIFEST for PGP 2.3a MSDOS executable release --------------------------------------------- Here is a list of files included in the PGP 2.3a MSDOS executable release file PGP23A.ZIP... README.DOC - This file you are reading BINFILES - The master list of files, used to generate the archive PGP.EXE - PGP executable program CONFIG.TXT - User configuration parameter file for PGP LANGUAGE.TXT - Sample language file for French and Spanish PGP.HLP - Online help file for PGP ES.HLP - Online help file in Spanish FR.HLP - Online help file in French KEYS.ASC - Sample public keys you should add to your keyring PGPSIG.ASC - Detached signature of PGP.EXE, to detect viruses DOC\SETUP.DOC - Installation guide DOC\PGPDOC1.DOC - PGP User's Guide, Vol I: Essential Topics DOC\PGPDOC2.DOC - PGP User's Guide, Vol II: Special Topics DOC\COPYING - GNU General Public Licence DOC\BLURB.TXT - Brief description of PGP, for BBS indexes DOC\POLITIC.DOC - Computer-related political groups For Clinical Paranoia Sufferers Only ------------------------------------ It is always possible that the PGP you have received has been tampered with in some way. This is a risk because PGP is used as a system to assure security, so those wishing to breach your security could likely do it by making sure that your copy of PGP has been tampered with. Of course, if you receive PGP in a binary distribution, it makes sense to check it for viruses, and if you receive PGP as source code, looking for signs of obvious tampering might be a good idea. However, it is very difficult to actually determine if the code has no subtle bugs that have been introduced and that the executable you are using has not been tampered with in any way. If you have a previous version of PGP which you already trust, the cryptographic signature on the executable will assure you that it has not been tampered with (with the possible exception of a "stealth virus" already existing on your system). If you are a really paranoid person, try getting a cryptographically signed copy of the software from someone you trust to have a good copy. It would also likely be good for you to pay special attention to the sections of the manual on "Vulnerabilities." You are going to read the manual, aren't you?