Email encryption - why is it a thing? Simply put, it is a way to ensure that only the receiver of your email will be able to see your missive. Nonencrypted email can easily be snooped on, which can lead to either embarassing or dangerous consequences.
Ladar Levison used to run an email service that was all about security, but rather than comply with orders from the US government to hand over user emails, Levison shut the service down. Now he's working on changing the very nature of email itself.
Privacy is paramount
Opposers of widespread encryption say that encrypted emails allow for criminals to mask their communications. Privacy proponents insist that it doesn't make sense to abuse the privacy of innocent people.
How Dark Mail works is to ensure privacy along the route, with the destination email server being able to identify the target of the email but not the sender. No way along the chain will the actual content of the email be vieweable by anyone but the receiver. Someone snooping on the transmission might, at most, be able to detect the size of an email but not what's in it.
All this is done via encryption keys, but as of now, the protocol is not yet workable or deployable. Currently the specifications are available online and the people behind Dark Mail are open to collaboration with other interested parties.
It will be interesting to see if Dark Mail can reach a stage where sending encrypted email will be a task easily taught to and used by laymen.