You can add an OpenPGP public key to your Facebook profile to receive encrypted email notifications from Facebook.
To retrieve the public key associated with your Hushmail account:
1. Go to http://www.hushtools.com
2. Select Key Management from the menu at the top
3. Type your email address
4. Click on Retrieve key
To add your public key to your Facebook profile:
1. Go to: https://www.facebook.com/me/about?section=contact-info (or open your Facebook profile and click About > Contact and Basic Info).
2. Under the contact information heading you should see an option that says "+ Add a public key". Click that option and a large text box appears.
3. Copy and paste your complete public key into that box—from the first line with the dashes to the last line with the dashes.
4. To encrypt your email alerts from Facebook, check the box below the text entry area that says "Use this public key to encrypt emails that Facebook sends to you?"
Facebook will send you an encrypted email that will include a link to confirm your choice. Once confirmed, you are ready to receive encrypted Facebook notifications: