[liberationtech] verifying SSL certs (was Re: In defense of client-side encryption)

[Guido Witmond]

On 08/14/13 15:18, Ben Laurie wrote:
> On 14 August 2013 08:54, Guido Witmond <guido at witmond.nl
> <mailto:guido at witmond.nl>> wrote:
> 
>     On 08/13/13 19:42, Andy Isaacson wrote:
>     > On Mon, Aug 12, 2013 at 11:10:39AM +0200, Guido Witmond wrote:
>     >> There is another problem. You rely on HTTPS. Here is the 64000
>     >> dollar question:
>     >>
>     >> Q._"What is the CA-certificate for your banks' website?"_
>     >>> 

[snip]

>     I too have given up on expecting security from the global CA's. That's
>     why I want to see DNSSEC succeed.
> 
> 
> DNSSEC merely transfers the problem to registries and registrars, who
> are no more reliable than CAs. You need to solve the problem of having
> to trust third parties before DNSSEC will work (which is the same
> problem you need to solve for CAs),

Yes, there is trust involved, but there is a difference.

With CA's anyone can sign a certificate for any site. It's a race to the
bottom with no winners. Not even the CA's as they can't differentiate
between themselves. The consequence is that no one trusts any of them.
And who likes to do business with a party he doesn't trust but needs anyway?

With DNSSEC, I have the choice of registrar. If there is a bad apple, I
choose another who I find better worth my money.


> And, sorry to bang on about it, but
> the answer is Certificate Transparency. BTW, my team is about to start
> looking at DNSSEC Transparency, too.

Don't bang to hard: DNSSEC and CT solve the same problem.

The problem is that there is no registry that specifies which of the
Global Certificate authorities is the one you should trust to validate a
server-certificate. The mess we have right now is that each of the
Global CA's can sign a server certificate. Hence my 64000 dollar question.

Both DNSSEC and CT solve the problem. Albeit in different ways with
different pros and cons.

With DNSSEC and DANE, the site operator specifies *a priori* which CA he
uses to sign the server certificates. It can be a self signed certificate.

With CT, you register which CA has signed a certificate for a web site
*after the fact*.

We need them both! To keep the CA's and registrars honest. I really
appreciate your work on CT.

Guido.