KMail/gpg

You can use kmail and gpg to send encrypted or digitally signed mail. To do this, there are the buttons "sign" and "encrypt" in the kmail compose window. It appears if you click on "File|New|New message".

First make sure your gpg is properly set up:

gpg --list-keys

Check that

gpg --update-trustdb

does not deliver

gpg: no ultimately trusted keys found

If you have a keyring saved to your disk, reload ("import") it like this:

cat secring.skr | gpg --import

Then call kgpg and set your trust on this key to ultimate.