At 10:50 AM 5/7/96 -0700, Hal wrote:
Unfortunately we are left with a choice between three not very good possibilities: accept transitive trust and hierarchical key CA structures; use very flat hierarchies where one signer validates huge numbers of keys; or accept that only a small number of keys can be validated by key signatures. I think all these are troublesome and in fact it makes me question the whole notion of key signatures.
Some of the solution to this problem may come from the answer to the question, "What am I trusting the receiver with?" I can see a number of possibilities: (1) I just want an envelope so casual eavesdroppers can't read the mail. Given the people Rich Graves has been dealing with, I see this as a powerful reason to encrypt all private email, just as you might send all private postal mail in envelopes rather than on postcards. In this case, I don't need a lot of confidence. Yes, a man-in-the-middle (MIM) can read the mail, just as the post office can open the envelope. However, the rest of the world won't see it unless the MIM wants to get caught. End-to-end, out of band acknowledgements can ensure that the message gets thru. (If the people I'm going to the mountains with don't pick me up, and I got in-band acknowledgements, I WILL suspect a MIM.) (2) I am sending someone else's secrets to a perfect stranger. An example might be sending company confidential information to a researcher another company R&D center half way around the world. In this case, I want to get the key from a location approved by the owner of the secret, making the problem the companies and not mine. (3) I am sending information which, if released, might cause significant harm to me or someone close to me. I can't see sending information of this nature to someone I don't know really well. In this case, out-of-band key fingerprint exchanges will work well. Regards - Bill ------------------------------------------------------------------------ Bill Frantz | The CDA means | Periwinkle -- Computer Consulting (408)356-8506 | lost jobs and | 16345 Englewood Ave. frantz@netcom.com | dead teenagers | Los Gatos, CA 95032, USA