[cabfpub] [cabfman] Improving the security of EV Certificates

Ryan Sleevi sleevi at google.com
Thu Dec 19 00:27:48 UTC 2013

On Wed, Dec 18, 2013 at 4:08 PM, Eddy Nigg (StartCom Ltd.) <
eddy_nigg at startcom.org> wrote:

> On 12/19/2013 01:29 AM, From Ryan Sleevi:
> On Wed, Dec 18, 2013 at 3:23 PM, Eddy Nigg (StartCom Ltd.) <
> eddy_nigg at startcom.org> wrote:
>>  But this is exactly how Diginotar was detected however - basically a few
>> emails back I suggested that browser vendors nail the most important sites
>> in their browser as "pins" and allow users to pin additional certificates
>> to the respective sites. It's a very simple and efficient way to get some
>> protection and allows detection for the most important sites.
>  So your idea is that every end-user is capable of evaluating the
> security policy of the site, without input of the site operator?
> No, as not every user is capable or has the necessary
> interest/knowledge/integrity to monitor and review a log containing all
> issued certificates and to know what to do with this data. And I made the
> other arguments already at the managements list I think.

This continued refrain demonstrates such a complete misrepresentation of
the CT goals that I do not know how to further engage constructively or to
explain how misguided this is.

It has been repeatedly explained to you, by multiple parties, that it is
not the end users (that is, to use CA terms, "Relying Parties"), but
instead the site operators, who will be monitoring the CT log.

>   And who do these users yell at when pins break?
> There is most likely a reason if that happens, this way or the other. A
> knowledgeable users will know the difference and the others will not pin
> any certificates to start with.

So protection for nobody. Got it.

>   The suggesting that pinning is between user+browser, rather than
> site+browser, is certainly a far worse model, utterly incomprehensible and
> providing no value to end users.
> I certainly works for me - it even worked for Google as far as I
> understood.

As has been repeatedly explained, you don't understand.

At this point, I feel the only useful discussion or advice I can give you
is to read the drafts, because your understanding is so far misplaced that
it's impossible to engage in a constructive dialog without at least some
effort on your part.

>   Also, the idea that we should somehow balkanize the Internet, and only
> the "very important ones" get security, at the discretion of browsers, is a
> terrible one.
> It's where the attacks probably happen first with the most value.
>   CT provides protection for every single user and site operator on the
> Internet - surely you can agree that has value?
> That's a very worthy goal and I believe the vast majority get reasonable
> protection in any case already today. Otherwise we can stop using SSL if
> there is no value in the work CAs perform. Or change the rules, but don't
> basically double the work with another layer.
>   Regardless of the views of pinning, however, the continued failures of
> the WebTrust and ETSI audit schemes to "prevent" mis-issuance has
> demonstrated to root store operators that it is no longer acceptable for
> continued trust in CA operations.
> Well, that's a very bleak interpretation - of course there were a bunch of
> failures (making me real angry too), but nothing is 100% ever. Not even CT
> will that be, trust me.
>   By requiring audits be transparent - which CT does - it provides a much
> better trust signal to root stores and their users that the participating
> CAs are deserving of trust.
> I have no problem with some transparency - I'd be willing to hand over a
> list of all issued certificates to an agreed upon consortium (how about
> Google, Netcraft, EFF and Qualsys) for review if that would increase your
> trust of my work. However I'm not really interested to carry the costs your
> proposal implies (at least as far as I see it, with no real numbers yet)
> and our subscribers will be probably very upset because they'll have to pay
> for it in the end.
>   A simple audit letter from an AICPA accountant or a qualified auditor
> is no longer sufficient, as the continued events demonstrate.
> Can we skip auditing then if there is no value in that? Than everybody can
> become a CA as long as the certs are in the CT log?

Like so many of your replies, I feel you have intentionally chosen to
misinterpret my reply in order to further a goal that can only be seen as
willfully obstructionist.

That something is no longer sufficient does not at all suggest that it is
not necessary, nor that there is no value.

Eddy, I have tremendous respect for you and your efforts, but I feel at
this time, we've reached an impasse at being able to fruitfully and
productively discuss CT, its merits, and its risks. Without a good faith
effort on your part to actually understand what is being proposed, both in
terms of CT and pinning, and to explain your counter proposal, I feel there
is nothing further of value to be added to the discussion here.

As has been previously discussed (
https://cabforum.org/pipermail/public/2013-September/002233.html ), Google
Chrome intends to require Certificate Transparency for all EV certificates
issued after a future date. This is, as has been previously stated, an
additional requirement that Google Chrome is imposing on certificates that
it grants the EV badge to - in addition to, not in replacement of, the
existing auditing requirements according to the CA/Browser Forum's EV
Certificate Guidelines, and as documented at

We appreciate your continued feedback in these plans, but at present,
nothing has been shared that would cause us to re-evaluate these plans. CAs
that are unable to meet these requirements will naturally find that
certificates they issue will no longer appear as EV within Chrome, because
Chrome cannot be assured that the certificates are truly worthy of the
heightened trust communicated to end users. This may, and likely will,
extend to all certificates at a future point, at which point CAs that are
unable or unwilling to provide a publicly auditable log of their
certificates will find these certificates marked as no longer trustworthy
and operating in the public trust.

I do not say this to suggest we are inflexible, but merely to highlight the
importance that CA's should make good faith efforts to understand what
Certificate Transparency is and the problems it attempts to address and
solve, in order that they might provide constructive feedback that can be
used to inform and alter these plans, if necessary.

The point of CT is to provide a technical solution for what is and will be
very much a program requirement for CAs that are treated as trusted by
Chrome - namely, that all certificates be able to be audited, by any
interested party, and at any time, in conforming to both the stated CP/CPS
of the CA and to the program requirements of Chrome.

If there are alternative technical solutions that can meet that goal, we're
happy to discuss them, but pinning - both the solution you've described and
the solution that the rest of us have been using and implemented for the
past several years - is not and will never be that, so it's not worth
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