*  I installed it on Win2000 but it should work on Win 95,98,ME,and XP.

There are a number of different options available to you if you want to ensure the privacy of your email. These include certificates, pgp and gnupg. Can't really say much about certificates as I haven't used them and it looks like you need to use commercial companies such as verisign to get them and you have an annual yearly fee to deal with. Refer to http://www.seifried.org/security/cryptography/crypto-book/chapter-08.html for more information on certificates.

PGP or Pretty Good Privacy was one of the original programs that made good email encryption available to the masses. It was written by Philip Zimmermann a cryptographic expert working at MIT who released the program in 1991 as freeware and was subsequently dragged through the courts by the US government for 3 years. I really recommend visiting Phils home page and reading up on the history of pgp and the reasons why Phil wrote the software see http://web.mit.edu/prz/. PGP contains a patented algorithm however and is now owned by a private company which Phil is no longer associated with.

GnuPG is compatible with PGP and does not use the patented IDEA algorithm and so can be used without restriction. GnuPG is free software both in the terms of dollars and that the source code is freely available so you can see just what has been written into the program. See www.gnupg.org for more information. I chose to use GnuPG because I didn't have any trouble getting it working in linux and I trust the GNU foundation and support its ethos of sharing software and community focussed development. To understand in detail how GnuPG and encryption works refer to the GNU Privacy Handbook at http://www.gnupg.org/gph/en/manual.html

I went about getting outlook express to work by installing 3 programs, gnupg, WinPT (Windows Privacy Tray) and the Outlook Express plugin for gnupg GPGOE. Be aware that the programs are still being developed and while gnupg is a mature app the other 2 are in early stages of development and so may not yet be able to utilise all the features of gnupg. I strongly recommend that you read the information about the various programs at their websites to be aware of just what is available and also read the GNU Privacy Handbook to understand how to use GnuPG. That said the given my small amount of testing the applications were quite useable and enabled me to send signed and encrypted messages and verify and unencrypt them.

Setting up gpg.The easiest way I found to get encryption with gnupg working in outlook express was to:

1. Go to www.gnupg.org
2. Click on Frontends in the navigation bar (www.gnupg.org/frontends.html)
3. Scroll down the list of applications to WinPT and click on it (www.winpt.org)
4. Click on the Download link at the top of the page.
5. Under the Stable heading click on the WinPT graphical installer package and download it to your computer.
6. When it has been downloaded to your computer click on the application to run the installer. Just follow the wizard which is pretty straight forward. You will be asked to enter a name an email address and a pass phrase (CHOOSE A HARD TO GUESS PASSWORD SO THAT IF SOMEONE DOES GET HOLD OF YOUR PRIVATE KEY IT WOULD NOT BE EASY FOR THEM TO GUESS YOUR PASSWORD) and then the program will generate a public and a private key and ask you to save a backup of these keys when it has finished.
7. Once the installation and key generation has finished go to Start -> Programs -> WinPT and click on Windows Privacy Tray. You should then have a key icon appear in the right hand side of your panel near the clock.
8. Double click on this icon and the key manager window will open. Note -- right click on the icon to see some of the other options that are available. The file manager for example lets you encrypt documents to store on your harddisk or to send as attachments.
9. In the keymanager window you should see the user id that you entered when you generated the key. Right click on that entry and from the window of options that will appear select "Set as default key". That is the basics for setting up gpg and the WinPT frontend to it. Read the GNU Privacy handbook in order to understand just what it is that GnuPG does and to be aware of what you have to do in order to use it effectively. That includes how you distribute your public key, the importance of protecting your private key and how you can build a web of trust.

Getting GPG to work in Outlook ExpressNow that we have got GnuPG working we have to be able to use it to sign and encrypt mail in outlook express unless you want to install another mail client like mutt or use mozillas mail client, in order to do your email. Due to other security issues that might well be a good idea (see http://online.securityfocus.com/infocus/1579 for a good discussion on how to secure your email client program to protect your privacy and a comparison of some of the main clients available), but for the ease of simplicity we will use Outlook Express. To get it working we need to go to www.gnupg.org/frontends.html and

1. Click on "GPGOE" which is a plugin for Outlook Express (http://www.winpt.org/gpgoe.html).
2. Select the latest binary version and click on it to download it to your computer.
3. Unzip the file to your computer and read the Readme file.
4. Make sure that you have the GPGOE.dll and GPGOEInit.exe files in the same directory which will be the case if you have simply unpacked all the files to the same directory.
5. Then simply click on the GPGOEInit.exe to run the application and a pad lock icon should appear in the right hand side of the panel.
6. Right click on this icon and make sure that "Use default key" is selected.

Now when you open a compose message window in outlook express you will have 2 buttons "Sign" and "Encrypt" appearing in the tool bar. Click on "Sign" if you want to sign a message that you send click on encrypt to encrypt the message or both buttons to both sign and encrypt your message. Be aware that the person you are sending the message too must have a copy of your public key in order to be able to verify your signature or decrypt your message. You can practice sending messages to yourself to see how it works. Also note that selecting "Encrypt" or "Digitally sign" from Tools in the menu bar at the top of the Compose Message Window tries to use MS certificates not GnuPG to encrypt and sign the mail.