For kmail() and mutt(), you will need to install the packages gnupg, libgpgme, and cryptoplug. Add the following statement to ~/.xinitrc

“$(gpg-agent –daemon)”

The gpg-agent() holds your private key in non-swapable memory, very similar to ssh-agent() and makes it available to the kmail plugin.

Now, add the following to ~/.gnupg/gpg-agent.conf

pinentry-program /usr/bin/pinentry-qt
no-grab
default-cache-ttl 1800

These statements define the popup window to be used by gpg-agent.

Finally, within kmail:/Settings/Configure Kmail||Security/Cryptoplugins: select /usr/bin/crytoplug/gpgme-openpgp.so. Activate the plugin.

Send yourself a signed email to see if kmail colors it in pale green.

Mozilla and Mozilla Thunderbird are considerably easier to enable in PGP. Simply install the Enigmail plugin from within Tbird: /Tools/Options/Extensions|Get New Extensions.

Restart Tbird and configure under the “Enigmail” menu.

Again, send yourself a signed email and see if the Enigmail plugin will color the header bar correctly.

If in either case, the client shows your test message as anything other than green, it’s probably due to your “trust” settings in gpg() . Try:

gpg –update-trustdb

Tell it that you “ultimately” trust your own key.

Using GnuPG to digitally sign emails.

GNU Privacy Guard (GnuPG) is an open source version of the commercial Pretty Good Privacy (PGP) software for creating digital signatures. Next paragraphs will cover the creation of a key, exporting your key to a public keyserver, and finally adding your digital signature to email.

a) Installing GnuPG and creating your directory

emerge gnupg
mkdir $HOME/.gnupg

b) Creating a new key

gpg –gen-key

you should select ‘DSA and ElGamal’, ’1024′ as keysize, no expiration date for your key (be careful with this) and your personal data (name, email) and finally your passphrase.

Now that your key has been made, it needs to be exported to a public keyserver. While this is not required, it’s the easiest way for others to get your public key information and verify your information. To send your key, you’ll first need to know your Key ID.

c) Find your key ID

gpg –list-keys

/home/johndoe/.gnupg/pubring.gpg
——————————-
pub 1024D/XXXXXXXX 2003-12-12 John Doe john.doe@example.com
sub 1024g/ZZZZZZZZ 2003-12-12

Note that XXXXXXXX and ZZZZZZZZ and the rest of data are fictitious.

d) Now you can export your key to a public server

gpg –send-keys –keyserver wwwkeys.pgp.net XXXXXXXX

Now that your key has been created and published, you can start using it to sign emails. You’ll need to remember your Key ID for this step. If you don’t remember it, see the above code listing, step c).

Use the following steps to set up encryption in Evolution:

1. Click on Tools->Settings.
2. Select “Mail Accounts” button and the account that will be using the key.
3. Click Edit and then the Security tab. Enter your Key ID in the field entitled PGP/GPG Key ID.
4. Click OK.

Now when you compose a message, select Security->PGP Sign to add your digital signature to your email.