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.

    Tip

    The PGP_MIME page will talk you through setting up and using GnuPG


    Overview: GPG

    A web of trust comprises a group 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:

    • you ([email protected]) meet John Foo ([email protected]) who is already a member of the web of trust
    • you install gpg
    • you have a private/public key pair or generate one with
      gpg --gen-key

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

    • you find out your key's fingerprint (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 checks 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

    Note

    yours may be called 'secring.pub'

    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'"

    "Gpg does not seem to be running..."

    You get an error message like this whenever you start up? You need scripts to make it start and stop cleanly. You can get scripts here:

    Copy them into your ~/.kde/env and ~/.kde/shutdown folders, check permissions, and make sure they are executable.

    Still not working?

    Check which pinentry packages you have installed. You may find you are missing pinentry-qt4.

    Other Key Considerations

    From time to time you need to do some maintenance work on your keys. KGpg was written to make this easier. There you will be able to extend the life of your keys, refresh them if they have already expired, change your passphrase, or revoke a compromised key.