Re: PGP, Inc.

From:	IN%"raph@cs.berkeley.edu"  "Raph Levien"  5-MAY-1996 13:47:16.83

>   "Observers say SMIME's capabilities will let it replace software
>   based on the PGP code, which is widely used. Unlike SMIME, which uses
>   a structured certificate heirarchy, PGP relies on pre-certification
>   of clients and servers for authentication, a limitation SMIME doesn't
>   face."

	Can one use a web-of-trust for S/MIME, for the cases when a structured
hierarchy is exactly the _wrong_ thing to use? I'd think so, but I don't know
anything about it.

>   Thus, it's a reasonable guess that almost all S/MIME messages that
>pass through the wires will offer "virtually no protection," to quote a
>phrase from a paper co-authored by the principal designer of S/MIME's
>encryption algorithms
>(http://www.bsa.org/policy/encryption/cryptographers.html).

	A public breaking of some S/MIME messages would work to discourage
this unsafe mechanism. One wonders if PGP Inc. could sponsor some variety of
contest?
	-Allen

E. ALLEN SMITH wrote:
> 
>         Can one use a web-of-trust for S/MIME, for the cases when a structured
> hierarchy is exactly the _wrong_ thing to use? I'd think so, but I don't know
> anything about it.

   The S/MIME spec indicates the use of X.509v3 certificates, which, in
turn, are explicitly allowed to contain trust roots originating in the
client's local configuration. In other words, yes, the spec allows for a
Web of trust.
   The big question, of course, is how easy the key management will be
in such a case. Everything I've seen points to key management being
super-easy if you use VeriSign certs, and probably just as bad as PGP
otherwise. Unlike PGP, most e-mail clients will probably not come
configured with the capablity to sign other keys - in the X.500 world,
e-mail clients and "certification authorities" are two separate
applications.
   But it's too early to tell. There's a lot of ferment happening here.

Raph