Ladar Levison is probably most well-known to Ars readers as the founder of the secure e-mail service Lavabit, which he shut down in mid-2013 in an effort to avoid being forced to comply with a US government demand to turn over users’ e-mails. But his latest project is a lot grander in scope than a single hosted e-mail service: Levison is attempting, with the aid of some fellow crypto-minded developers, to change e-mail at large and build encryption into its fundamental nature.
As one of the members of the Darkmail Technical Alliance, Levison—along with Jon Callas, Mike Janke, and PGP designer Phil Zimmermann—is working on a project collectively referred to as DIME, the Dark Internet Mail Environment. DIME will eventually take the form of a drop-in replacement for existing e-mail servers that will be able to use DMTP (the Dark Mail Transfer Protocol) and DMAP (Dark Mail Access Protocol) to encrypt e-mails by default.
Conceptually, DIME applies multiple layers of encryption to an e-mail to make sure that the actors at each stage of the e-mail’s journey from sender to receiver can only see the information about the e-mail that they need to see. The e-mail’s author and recipient both know who sent the message and where it was bound, but the author’s e-mail server doesn’t—it can only decrypt the part of the message containing the recipient’s e-mail server. The recipient e-mail server knows the destination server and the recipient, but it doesn’t know the sender. So if you arrange the four steps in a line from left to right—author, origin server, destination server, and recipient—each step in the line is only aware of the identity of the entity directly to its left or right.