Of course a system such as this will not provide you with foolproof protection against any adversary ever. If that is what you need, email is not what you're lo

Of course a system such as this will not provide you with foolproof protection against any adversary ever. If that is what you need, email is not what you're looking for, period. But there is in fact an enormous difference between the proposed system and traditional email hosting. With traditional email hosting, all it takes is one FISA rubber stamp, one hacker gaining access to the mailserver or any of its backups, one rogue or compromised employee to access the entire history of every email you have ever received or sent. In the proposed system, assuming it is properly implemented, the only way to snoop on your emails is tapping the line between the local and remote SMTP server, easily prevented if both parties use SSL. The system could even, based on the user preferences, warn about this ("Warning: this email was not delivered via SSL, it could thus have been intercepted while on the wire") or block incoming/outgoing SMTP entirely if the remote party doesn't support SSL. It's not a solution against (government) snooping per se, especially not a solution against a party such as the US government specifically targetting you. But it is a defense against half of the world population's email history indefinitely being stored in your friendly neighborhood NSA facility.