John Gardiner Myers wrote:
Ian Grigg wrote:

David Ross wrote:

Clearly (at least to me), the answer is:  The primary and most
important use of a CA certificate is to provide the Mozilla user
with assurance that (1) a critical Web site is indeed what it
purports to be


(This is not clear at all.  I think it rests on
a number of false assumptions, but those are
quite hard to describe in a quick email, so
I'll skip that here.)


As (1) is the definition of a certificate (modulo the fact that applicability goes beyond just web sites), it is as clear to me as any derivation from definitions. That you state it is not clear, omitting any argument, is in no way convincing.


Sorry, yes, I should have left that bit out.
The underlying fact here is that a CA certificate
carries a signature from a third party (CA)
on a key for a second party (website).

That's a cryptographic fact, in general, and
other claims are assumptions that may or may
not be founded.

It's by no means definitional whether that
signature delivers anything like "providing
assurance that a critical web site is indeed
what it purports to be."  The question is
whether we can move from a cryptographic
statement (this key signs that key) to a
business statement (this site is who they
say they are) with any degree of confidence.

The answer to that seems to be no.  Not with
any confidence.

Just as an example of one only amongst a
long list of difficulties, the present issue
is that, as no browser goes to any trouble to
to separate out *which* CA made the claim,
the confidence is reduced to the lowest
common denominator.  (There are many more
issues, but that one is apropos.)


iang



PS: C.f, branding discussion started by Tim Dierks. AFAIK, Peter Gutmann first made the observation about "one size" security policy resulting in no security.

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