Email Self Defense by the Free Software Foundation (FSF)

FSF Email Self Defense - Full Guide

https://emailselfdefense.fsf.org/

FSF Email Self Defense - Infographic

https://emailselfdefense.fsf.org/static/img/en/full-infographic.png

FSF Email Self Defense - Teachable Guide

https://emailselfdefense.fsf.org/en/workshops.html

The Intercept - PASSPHRASES THAT YOU CAN MEMORIZE BUT THAT EVEN THE NSA CAN’T GUESS

https://theintercept.com/2015/03/26/passphrases-can-memorize-attackers-cant-guess/

Wired Magazine - These Are the Emails Snowden Sent to First Introduce His Epic NSA Leaks

http://www.wired.com/2014/10/snowdens-first-emails-to-poitras/