Perhaps you have noticed the strange extra text in computer code that comes with many of my e-mails. These are digital signatures. You can use any program compatible with the PGP ("pretty good privacy") standard to verify that messages came from me, not from an impostor. I recommend the programs Mutt and GnuPG (see below).
Why is this necessary? E-mail was designed in the days when Internet users numbered in the hundreds, rather than in the millions as today. It has no provision for security. It is trivially easy for almost anyone to send an e-mail message that seems to come from me, you, or one of your associates.
This situation is not acceptable for anyone who uses e-mail to conduct business. But worse yet, anyone with access to the computers through which an e-mail travels can read or even alter its contents. For this reason I recommend that anyone who uses e-mail for business purposes or sensitive private communication use a cryptography system.
For further background information in PGP, see Wikipedia's PGP article.
In these days of the PATRIOT Act and routine invasions of our privacy by a government bent on turning USA into a police state, it is more important than ever to encrypt your e-mail. According to privacy watchdog groups, the US govenment's Carnivore program is quite possibly reading your e-mail right now. I am a law-abiding citizen who objects to such spying without cause.
Encrypting as many of my private e-mails as possible is my protest. I urge you to consider doing the same. If you live in the USA, I also urge you to write your senators and congress representative (information available from ACLU) to let them know that you do not want our civil rights thrown away in a misguided attempt at national security.
If you are still not convinced that this is a good idea, I recommend reading the article Why do you need PGP?.
You may obtain my public key here: hajhouse.asc. I encourage you to send me PGP-encrypted messages.
The specific PGP program that I use to encrypt and sign e-mail is GnuPG (GNU Privacy Guard). It is compatible with the original PGP program (Pretty Good Privacy). GnuPG software and documentation may be downloaded from here: gnupg.org.
I use the program Mutt on Linux to read and compose my e-mail. Mutt has integrated PGP support that is very easy and convenient---highly recommended. As far as I know, these programs are only available for Linux and Unix.}If you are a Mac or Windows user, then I recommend the site International PGP. Look under "Documentation" for guides that show you how to use PGP and "Download" to get the software (there is no cost).
Sorry, I am too busy to help you with PGP problems. There are excellent mailing lists that offer help linked from the aformentioned web sites. For Linux users, I recommend also the Linux Users' Group of Davis (look under "Mailing lists").
Assuming you use procmail, this may be rectified by adding the following recipe to the beginning of your .procmailrc:
# convert traditional-format PGP messages to MIME
:0
* !^Content-Type: message/
* !^Content-Type: multipart/
* !^Content-Type: application/pgp
{
:0 fBw
* ^-----BEGIN PGP MESSAGE-----
* ^-----END PGP MESSAGE-----
| formail -i "Content-Type: application/pgp; format=text; x-action=encrypt" -A "X-Procmail:
converted traditional format PGP encryption"
:0 fBw
* ^-----BEGIN PGP SIGNED MESSAGE-----
* ^-----BEGIN PGP SIGNATURE-----
* ^-----END PGP SIGNATURE-----
| formail -i "Content-Type: application/pgp; format=text; x-action=sign" -A "X-Procmail:
corrected traditional-format PGP signature"
}