OpenPGP Signing and Encryption



Enigmail is a Postbox Labs project that allows you to encrypt and digitally sign emails using the OpenPGP standard for increased security and privacy. Enigmail is free and released under an open-source license.

Here are simplified instructions to help you get started with Enigmail. These instructions assume that you have installed Postbox but have not previously installed Enigmail or OpenPGP.

Installing Enigmail

  1. Download Enigmail for Postbox.
  2. In Postbox, navigate to the Tools menu and select Labs.
  3. Click the preferences icon in the upper right, then select Install Labs Project From File... from the contextual menu.
  4. Navigate to the Enigmail file that you downloaded to your computer and install it. When finished, close the Labs tab.
  5. In Postbox, open a Compose window, then from the Enigmail menu, select Preferences > Setup Wizard.
  6. When asked to set up GnuPG, click the Install GnuPG... button.

    IMPORTANT: on macOS, you must install the GnuPG OSX version (with 'OSX' in the name).

    Install OpenPGP in Email
  7. When the GnuPG install process is complete, you will see the following confirmation:

    "Enigmail is now properly configured and ready for use."

Configure Postbox

  1. In Preferences | Options, navigate to Accounts > [your email account] > OpenPGP Security.
  2. Select the Enable OpenPGP support (Enigmail) for this identity checkbox.

Share Your Public Key

To communicate securely with another individual, they must have your public key, and you must have theirs. The first step is to share your public key with the recipient.

  1. Open the Compose Window.
  2. From the Enigmail menu, select Attach Public Key..., then in the next panel, select the key you wish to attach to the message. 
  3. Remember to ask the recipient to send to you their public key, then send the message with your key.

Receiving a Public Key

When you receive a public key, you must add it to Postbox. In the message that contains the shared key, right-click the attachment, then select Import OpenPGP Key.

Import OpenPGP Key

Sending an Encrypted and Signed Message

Now, you're ready to send an encrypted and signed message. 

  1. Open the Compose window, and address and compose your message normally.
  2. In the Toolbar, click the Lock button to encrypt the message and the Pencil button to sign the message.
  3. Send the message.

Receiving Encrypted and Signed Messages

When you receive an encrypted and/or signed message, Postbox will display confirmation icons in the message header. A signing icon with an orange question mark indicates that you have not yet certified the sender. 

View an Encrypted Message in Postbox

To certify the sender:

  1. Click the signing icon to bring up the Enigmail Security Info Panel, then click the Open Key Properties button.
  2. Under the Basic tab > Validity, click the Certify button.
  3. Select a certification level. If you fully trust the entity that signed the message, select I have checked very carefully. Close the Enigmail panels.
  4. Restart Postbox for these changes to take effect. 

Once you've certified the sender, the signing icon will display with a green check icon.

View an Encrypted Message

Your email messages now have a higher level of security and privacy!

Help and Additional Resources

Enigmail is developed and supported by a team of 3rd-party developers. For additional documentation and support, please visit the Enigmail website.


This documentation contains contributions originally posted by the Enigmail team on the Enigmail websites, forums, newsgroups, and mailing lists.

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