KMail/gpg

From KDE UserBase Wiki

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".

Overview: GPG

A web of trust are a lot of persons who trust each other. To show their trust, they have signed each other's keys. gpg allows you to do this.

The web of trust is extended in key signing parties that go like this:

gpg --gen-key

Your private key is stored in secring.gpg, your public one is stored in pubring.gpg. You keep your private key and are free to distribute your public key.

  • you find out your key's name
gpg --list-keys
/home/me/.gnupg/pubring.gpg
----------------------------------
pub   1024D/45E377BB 2008-02-03
[...]
  • you upload your public key to your key server
gpg --send-key
  • John downloads your key from the key server
gpg --search-key me@home
  • John controls your passport and signs your key
gpg --sign-key 45E377BB
  • John uploads your key again
gpg --send-key 45E377BB
  • You are now part of the web of trust and your public key is on the key server.

How to...

Import a saved keyring

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 your private key to ultimate.

TroubleShooting

Whatever problems arise, first make sure your gpg is properly set up:

  • List your keys
gpg --list-keys
Has to deliver something like a sensible list of keys.
  • Check the output of
gpg --update-trustdb
In case of a problem look at the below.

no ultimately trusted keys found

If

gpg --update-trustdb

delivers

gpg: no ultimately trusted keys found

Call kgpg and set the trust of your private key to ultimate.