Email encryption with Thunderbird

Set up

Thunderbird 3.0.3 OpenPGP (Enigmail 1.0.1).

Create keys

1. OpenPGP -> Key Management.
2. Select ‘Display All Keys By Default’.
3. Generate -> New Key Pair.
4. Select account.
5. Tick ‘No passphrase’.
6. Remove comment (as it’ll be available to those whom you send your public key).
7. Generate key.
8. Generate a revocation certificate when you get a popup asking whether you’d like to.
9. Close the Key Management window.

Distribute your public key

1. Create an email.
2. OpenPGP -> Attach My Public Key.
3. Send to whoever you’ll send signed emails or from which you’ll receive encrypted emails.

Receive a public key

If you receive someone’s public key as an attachment, right click it and select ‘Import OpenPGP Key’.

Send signed mail

The receiver will need your public key in order to verify the signature.

1. Create an email.
2. Click the OpenPGP button and select ‘Sign Message’.
3. Send.

Send encrypted mail

You will need the receiver’s public key for this.

1. Create an email.
2. Click the OpenPGP button and select ‘Encrypt Message’.
3. Send.

Gotchas

Can’t save draft messages

If you get the following error when trying to save a draft message…

Encrypt draft messages on saving

The email address or key ID ‘0x2ABBGC01’ cannot be matched to a valid, not expired OpenPGP key. Please ensure that you have a valid OpenPGP key, and that your account settings point to that key.

…then it could be that Enigmail is configured to use that invalid key.

To fix, do the following (with Enigmail 1.8.2 at least!):

1. Go to Preferences -> Account Settings.
2. Select the ‘OpenPGP Security’ section of your email account.
3. Check that the ‘Use specific OpenPGP key ID’ option is not set to the invalid key.
4. Alternatively, to prevent Enigmail encrypting draft messages, deselect ‘Encrypt draft messages on saving’.

Reference: Problem with Enigmail on Tbird/Mac

Last modified: 29/04/2015 Tags: thunderbird, openpgp, enigmail