public-key: the wrong model for email?

[Ed Gerck]

Adam Shostack wrote:

> On Thu, Sep 16, 2004 at 12:05:57PM -0700, Ed Gerck wrote:
> | >Adam Shostack wrote:
> | >
> | >I think the consensus from debate back last year on
> | >this group when Voltage first surfaced was that it
> | >didn't do anything that couldn't be done with PGP,
> | >and added more risks to boot.
> | 
> | Voltage actually does. It allows secure communication
> | without pre-registering the recipient.
> 
> Generate a key for "unknown-recipient at foocorp.com" encrypt mail to
> Bob to that key.  When Bob shows up, decrypt and send over ssl.

How do you know when the right Bob shows up? And...why encrypt? The
email never left your station. Your method is equivalent to: send
anything to Bob at "unknown-recipient at foocorp.com". When Bob shows
up pray he is the right one and send email over ssl. You also have to
run an ssl server (or trust Bob's server key).

With Voltage, you encrypt the email to "unknown-recipient at foocorp.com"
and send it. The sender's work is done[*]. Yes, the other problems still
exist with Voltage.

Cheers,
Ed Gerck

[*] The recipient can decrypt the Voltage email only IF both the sender
and  recipient can refer to the same key generation parameters for the
recipient. This is a problem that I have not seen Voltage discuss. Users
in different or competing administration boundaries will not be able
to communicate with each other in general.

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