
We've known for decades how difficult it is to encrypt email. We've developed E3, a client-side system that encrypts email at rest on mail servers to mitigate the most common cases of attacks today. E3 also demonstrates techniques for making key management simple enough for most users, including those who use email on multiple devices.
Email privacy is of crucial importance. Although email accounts and servers contain troves of valuable private information dating back years, they are easy to compromise. This makes them attractive targets for adversaries. Attackers often use methods such as spear-phishing, password recovery and reset, and social engineering attacks to obtain a victim's email credentials. With login details in hand, attackers then simply authenticate to the appropriate mail service like a normal user and siphon off all of the victim's emails.