Re: DNSCurve vs. DNSSEC - FIGHT! (was OpenDNS today announced it has adopted DNSCurve to secure DNS)

[Shumon Huque <[e-mail]>]

On Tue, Mar 02, 2010 at 06:13:28AM +0900, Masataka Ohta wrote:
> Phillip Hallam-Baker wrote:
> 
> > Moving to DNSSEC, regardless of the technical model does not eliminate
> > the need for certificates or CAs. The purpose of EV certificates is to
> > re-establish the principle of accountability.
> 
> I don't know what EV means, but anything human, including CA, is not
> infallible, which is why PKI is insecure.

"EV" = Extended Validation certificates.

Re-establishing (Establishing?) the concept of accountability, I think, 
requires more than introduction of EV certificates. Assuming that there 
is even agreement that they have a more accountable CPS, it also requires
removal of the allegedly non-accountable CAs from trust anchor lists.
This hasn't happened.

There is also the question of the actual effectiveness of EV
certificates. Do they really work? Can their indicators be spoofed?
And can normal users use their visual cues to actually make informed 
security decisions? There appears to be a growing body of empirical
work that shows that the typical user is unable to make effective 
security decisions based on certificates and their complex set of 
indicators (whether they are EV branded or not).

Here are a few pointers, which I'm sure many folks on this list are
well aware of ..

* An Evaluation of Extended Validation and Picture-in-Picture Phishing Attacks
  ISSN    0302-9743 (Print) 1611-3349 (Online)
  Financial Cryptography and Data Security, 2007
  http://www.adambarth.com/papers/2007/jackson-simon-tan-barth.pdf

* Why Phishing Works
  http://people.seas.harvard.edu/~rachna/papers/why_phishing_works.pdf
  2006

* The Emperor's New Security Indicators: An evaluation of website
  authentication and the effect of role playing on usability studies.
  http://www.usablesecurity.org/emperor/
  May 2007

* Crying Wolf: An Empirical Study of SSL Warning Effectiveness
  http://www.usenix.org/events/sec09/tech/full_papers/sunshine.pdf
  July 2009

And the paper I know of that supports the effectiveness of EV:

* Extended Validation SSL: Green Address Bar Consumer Research
  Verisign/Thawte/Tec-Ed study:
  http://www.verisign.com.sg/guide/ssl-ev/EV-SSL-GreenBarResearch.pdf

There have been extensive discussions on this topic on various other
lists (cryptography, w3c, etc), and I'm not sure I look forward to
seeing all of it rehashed on the IETF list. But I would be interested
in pointers to other credible studies on this topic.

--Shumon.