Re: Questions about MD5+CA

[Jon Oberheide <jon () oberheide org>]

On Sat, 2009-01-03 at 02:47 +0100, wishi wrote:
> Dave Aitel schrieb:
> > Totally. This was a good opportunity for Mozilla or the IE team to be
> > thought leaders in security, and neither stepped up. The right thing
> > to do would have been to announce an update that disabled the root CA
> > in 10 days. That gives everyone ten days to get a new certificate from
> > somewhere else. Security is about hard choices. Currently, we're all
> > about sticking our heads in the sand - which devalues SSL as a
> > security protocol entirely.
[snip]
> > > If they don't revoke the root, the security of the PKI system from
> > > now until 2020 (when the RapidSSL cert expires) will rely on the
> > > assumption that our team did not make a second CA cert that nobody
> > > knows about and that nobody else did either. We didn't, but how can
> > > we possibly prove that? How can any CA that used MD5 prove beyond
> > > doubt that they have not signed a colliding key in the past?
[snip]
> Security is about choices. For sure. About the choice to maximize profit
>  at all costs, or not. That brings me back to "Perspectives" - the
> firefox add on. I personally don't trust CAs, or huge PKIs. Latter
> always get weaker, the larger they grow. And CAs are an economy of
> strangely named companies that no one transparently monitors.
>
> It's interesting: in theory PKIs work very well, as long as there's no
> money. ;)

On the other hand, I'd argue that PKIs are more effective when there
_is_ money involved.

While CAs will of course attempt to maximize profits, any commericial
root CA included in popular browsers has a significant economic
incentive to maintain its trust and reputation.  Without revocation of
the offending root CAs by browser vendors, it is sending a message that
poor security practices will not be punished.

Responsible (and justified, in this case) revocation is the only way to
ensure that economic incentives continue to exist (eg. "Revocation costs
us X dollars so we need to invest Y dollars to ensure our compliance")
to improve the security practices of these CAs.

Regards,
Jon Oberheide

-- 
Jon Oberheide <jon () oberheide org>
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