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
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