There are two (interoperable) standards for encrypting email,
OpenPGP and
S/MIME. In what follows, I will walk through the process for OpenPGP.
Step 1. Install OpenPGP software tools.
Although many implementations exist, one good option is using the
Gnu Privacy Guard (or GnuPG) implementation. This software will allow you to create credentials, manage their distribution, and encrypt documents. Binaries are provided for Windows and Mac OS X. Binaries for various Linux flavors are typically provided through the associated distribution.
Step 2. Create credentials.
Users participating in encrypted email identify themselves via their public key. The public key is encoded into a "certificate". The tools installed in step 1 can be used to create these credentials. For example, if you are using GnuPG on Windows (that is,
Gpg4win), you can:
a. launch the Kleopatra tool
b. go to File -> New Certificate
c. select "Create an personal OpenPGP key pair"
d. enter your full name and email address associated with this certificate
e. enter a
strong passphrase
A few notes on this process. You should create one and only one public key for each email address you will be using for secure communication. The process will create both a private and a public key. The private key should be kept in a secure location. It does need to reside on the machine that will be used to encrypt or read secure email, but otherwise should not be copied unnecessarily to other machines. It should however be backed up in a secure location, for example a USB flash drive or equivalent.
Step 3. Publish public key to public key server.
Your public key should be posted to a public PGP key server. See for example the open director project for a
list of key servers. For example, I have uploaded my key to the
MIT PGP Key Server. You can find my various keys by
searching for "hotes".
Step 4. Install a plugin for your email client.
OK, this can be trickier. Here are a few options:
-
Outlook Privacy Plugin (Outlook 2010, free, on Google Code)
-
GpgOL GnuPG Outlook Extension (Outlook 2003+, free)
- Symantec
PGP Desktop Home (Outlook 2003+, $99 for 1 yr. license)
-
The EnigMail Project (Thunderbird, free)
Also see this
list of plugins.
If you are using web-based email (like Hotmail or GMail), OpenPGP extensions have been made for Firefox and Chrome, but I don't know how well they have been supported. For example, the once popular FireGPG Firefox extension providing PGP support for GMail is
now defunct. Your best option here is to use POP/IMAP and a native email client.