public-key: the wrong model for email?

[Eugen Leitl]

On Fri, Sep 17, 2004 at 07:35:09PM +0100, Ian Grigg wrote:

> Oh, that's really easy.  Each mailer (MUA) should (on
> install) generate a self-signed cert.  Stick the fingerprint

apt-get install postfix-tls

Allright, this still doesn't generate the certs, nor reference them in the
main.cf.

> in the headers of every mail going out.  An MUA that sees
> the fingerpring in an incoming mail can send a request email
> to acquire the full key.  Or stick the entire cert in there,
> it's not as if anyone would care.

I would cache the cert fingerprints, and log when those change.
 
> Then each MUA can start encrypting to that key opportunistically.

Start/TLS does encrypt my mail far more often the PGP/GPG.
 
> Lots of variations.  But the key thing is that the MUA
> should simply generate the key, sign it, and send it out
> on demand, or more freuqently.  There's really no reason
> why this can't all be automated.  After all, the existing
> email system is automated, and trusted well enough to
> deliver email, so why can't it deliver self-signed certs?

Talk to Exim/Postfix maintainers. They should ship self-signed cert Start/TLS
config out of the box. Even without cert caching, that'd require a MITM.
Not exactly cheap, and prone to detection, if practiced on a nonnegligible
scale (fingerprint checking).

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a>
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Eugen* Leitl <a href="http://leitl.org">leitl</a>
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