Revised 12th of January 1998
Disclaimer: some of this information may be outdated or otherwise inaccurate. Use it at your own risk.
The master copy of this FAQ is at http://www.cryptography.org/getpgp.htm (and at http://www.cryptography.org/getpgp.txt for the text-only version) .
The official (much more complete) PGP FAQ is available at: http://www.pgp.net/pgpnet/pgp-faq/
If you are in the USA or Canada, try one of these URLs:
MANY BBS carry PGP. The following carry recent versions of PGP and allow free downloads of PGP.
If you have access to email, but not to ftp, send a message saying "help" to ftpmail@decwrl.dec.com or mailserv@nic.funet.fi
Yes. You can get the official PGP documentation in several languages at http://www.pgpi.com. German documentation is at http://www.geocities.com/Athens/1802/ Thanks to Florian Helmberg <helmberg@via.at> for making it available.
PGP 5.0 introduces some new algorithms for both public key and conventional encryption. These changes are good from both technical (security & efficiency) and political (patent) standpoints. With the death of the Diffie-Hellman key exchange patent, the freeware PGP new algorithms are 100% free of patent problems, and free of legalese such as come with the RSAREF toolkit. The Diffie-Hellman key exchange key size limit is also larger than the old RSA limit, so PGP encryption is actually more secure, now. The new SHA1 hash function is better than MD5, so signatures are more secure, now, too. The conventional encryption used is all sound, and definitely not the weak link in the chain. This much is good news.
The bad news, of course, is that there will be some interoperability problems, since no earlier versions of PGP can handle these algorithms. How this affects you depends on the PGP version that you have.
There are really 3 versions of PGP called PGP 5.0. The freeware edition can only generate and use the new (faster, more secure, patent-problem-free) algorithms. There is a really cheap (cheaper than one S/MIME key certificate) upgrade to PGP 5.0 for Eu dora users that will let you use the old RSA keys as well. Then, of course, the full commercial version of PGP 5.0 can handle both old and new algorithms and message formats equally well. If you want to handle both, you need to either keep both an old and new freeware PGP around, upgrade to one of the versions of PGP 5.0 that can handle the old keys.
Pretty Good Privacy is legal if you follow these rules:
Don't export PGP from the USA except to Canada, or from Canada except to the USA, without a license (except that printed books containing source code are OK to export).
If you are in the USA, use either the commercial PGP (licensed for commercial use) or MIT PGP using RSAREF (limited to personal, noncommercial use), or use one of the versions of PGP that doesn't support RSA encryption and digital signatures and use th e Diffie-Hellman and DSA algorithms (that aren't patented).
Outside of the USA, where RSA is not patented, you may prefer to use a version of PGP (2.6.3i) that doesn't use RSAREF to avoid the restrictions of that license.
If you are in a country where the IDEA cipher patent holds in software (including the USA and some countries in Europe), make sure you are licensed to use the IDEA cipher commercially before using PGP commercially. (No separate license is required to u se the freeware PGP for personal, noncommercial use). For direct IDEA licensing, contact Ascom Systec:
Erhard Widmer, Ascom Systec AG, Dep't. CMVV Phone +41 64 56 59 83 Peter Hartmann, Ascom Systec AG, Dep't. CMN Phone +41 64 56 59 45 Fax: +41 64 56 59 90 e-mail: IDEA@ascom.ch Mail address: Gewerbepark, CH-5506 Maegenwil (Switzerland)
PGP, Inc., has an exclusive marketing agreement for commercial distribution of Philip Zimmermann's copyrighted code. (Selling shareware/freeware disks or connect time is OK). This restriction does not apply to PGP 3.0, since it is a complete rewrite by Colin Plumb.
If you modify PGP (other than porting it to another platform, fixing a bug, or adapting it to another compiler), don't call it PGP (TM) or Pretty Good Privacy (TM) without Philip Zimmermann's permission.
Philip Zimmermann was under investigation for alleged violation of export regulations, with a grand jury hearing evidence for about 28 months, ending 11 January 1996. The Federal Government chose not to comment on why it decided to not prosecute, nor i s it likely to. The Commerce Secretary stated that he would seek relaxed export controls for cryptographic products, since studies show that U. S. industry is being harmed by current regulations. Philip endured some serious threats to his livelihood and f reedom, as well as some very real legal expenses, for the sake of your right to electronic privacy.
The battle is won, but the war is not over. The regulations that caused him so much grief and which continue to dampen cryptographic development, harm U. S. industry, and do violence to the U. S. National Security by eroding the First Amendment of the U. S. Constitution and encouraging migration of cryptographic industry outside of the U. S. A. are still on the books.
If you are a U. S. Citizen, please write to your U. S. Senators, Congressional Representative, President, and Vice President pleading for a more sane and fair cryptographic policy. Several legislative efforts will, if successful, relax the export contr ols of cryptographic software from the U.S.
See:
Within the U.S. there is no legal obstacle for use of strong encryption.
In an ideal world everyone would have the right to use encryption. Unfortunately, your right to use encryption may be restricted or does not exist.
In France, the government prohibits the use of encryption without prior permission, that you won't get if you are a private citizen.
Germany is said to consider banning the use and distribution of strong cryptographic software in the name of "national security."
United Kingdom may adopt a key escrow system.
For a recent update on the legal situation see The Crypto Law Survey http://cwis.kub.nl/~frw/people/koops/lawsurvy.htm
See:
PGP can do conventional encryption only of a file (-c) option, but you might want to investigate some of the other alternatives if you do this a lot.
Alternatives include Quicrypt and Atbash2 for DOS, DLOCK for DOS & UNIX, Curve Encrypt (for the Mac), HPACK (many platforms), and a few others.
Quicrypt is interesting in that it comes in two flavors: shareware exportable and registered secure. Atbash2 is interesting in that it generates ciphertext that can be read over the telephone or sent by Morse code. DLOCK is a no-frills strong encryption program with complete source code. Curve Encrypt has certain user-friendliness advantages. HPACK is an archiver (like ZIP or ARC), but with strong encryption. A couple of starting points for your search are:
If you have the Norton Utilities, Norton WipeInfo is pretty good. I use DELETE.EXE in del110.zip, which is really good at deleting existing files, but doesn't wipe "unused" space.
PGPfone is for private telephone calls over a modem or the Internet.
Bill Dorsey, Pat Mullarky, and Paul Rubin have come out with a program called Nautilus that enables you to engage in secure voice conversations between people with multimedia PCs and modems capable of at least 7200 bps (but 14.4 kbps is better). See:
Secure File System (SFS) is a DOS device driver that encrypts an entire partition on the fly using SHA in feedback mode.
Secure Drive also encrypts an entire DOS partition, using IDEA, which is patented.
Secure Device is a DOS device driver that encrypts a virtual, file-hosted volume with IDEA.
Cryptographic File System (CFS) is a Unix device driver that uses DES. CryptDisk is a ShareWare package for Macintosh that uses strong IDEA encryption like PGP. http://www.cs.auckland.ac.nz/~pgut0 1/sfs.html ftp://ftp.informatik.uni-hamburg.de/pub/virus/crypt/disk/ ftp://ftp.nic.surfnet.nl/surfnet/net- security/encryption/disk/ ftp://sable.ox.ac.uk/pub/crypto/misc/ ftp://menja.ifi.uio.no/pub/pgp/mac/ ftp://basement.replay.com/pub/replay/pub/disk/ http://www.cryptography.org ftp://miyako.dorm.duke.edu/mpj/crypto/disk/
S/MIME is gaining a foothold on the secure email market, but my experience with it has been rather negative. Current implementations of S/MIME (1) don't allow secure key lengths to be used except in "U. S. Only" versions, (2) require payment of an annu al fee to a key certification authority who verifies only that you got email to your key certificate's address at least once, (3) have much more limited key management facilities than PGP, and (4) the first time I tried to make S/MIME work, it flat out fa iled to perform as advertised. On the positive side, S/MIME is integrated into email packages almost as well as PGP is integrated into Eudora, and once the kinks are taken out, the secure version of S/MIME (1024-bit RSA keys and 128-bit RC-2 keys) will be good enough for most people. The "export" edition (512-bit RSA keys and 40-bit RC-2 keys) is a very bad idea, because it gives a false sense of security.
RIPEM is the third most popular freeware email encryption package. I like PGP better for lots of reasons, but if for some reason you want to check or generate a PEM signature, RIPEM is available at ripem.msu.edu. There is also an exportable RIPEM/SIG.
U.S. and Canada: ftp://ripem.msu.edu/pub/GETTING_ACCESS International: ftp://idea.sec.dsi.unimi.it/pub/crypt/code/
The latest PGP version will interact with key servers automatically if you are connected to the Internet and if you configure them to. For manual key publication, send mail to one of these addresses with the single word "help" in the subject line to find out how to use them. These servers synchronize keys with each other. There are other key servers, too.
http://www.pgp.net/pgpnet/www-key.html
You can have your key officially certified and published in a "clean" key database that is much less susceptible to denial-of-service attacks than the other key servers. Send mail to info-pgp@Four11.com for information, or look at http://www.Four11.com/
Of course, you can always send your public key directly to the parties you wish to correspond with.
Yes. Please only do so in appropriate forums, and provide pointers to the home location of this FAQ.
William Knowles erehwon@dis.org
Last updated 3.07.98