[cryptography] Let's go back to the beginning on this

Seth David Schoen schoen at eff.org
Tue Sep 13 19:44:06 EDT 2011

Ralph Holz writes:

> Yes, with the second operation offline and validating against the NSS
> root store. I don't have a MS one at the moment, it would be interesting
> (how do you extract that from Win? The EFF guys should know)

You might look at https://www.eff.org/files/ssl-observatory-code-r1.tar_.bz2
in the microsoft_CAs directory.

You can also look at


which used to provide a PDF, but apparently now links to


instead (not updated to reflect DigiNotar's removal).

One issue is that Microsoft has a protocol for MSIE to ask Microsoft
interactively whether to trust a new CA.  That means that the list of
trusted CAs is not actually stored on an MSIE end-user's machine and
can't be displayed in full inside of MSIE.  Instead, when a new CA is
encountered, MSIE will query Microsoft and ask whether that CA should
be trusted.  Personally, I find this indeterminism and delegation
concerning (since there's no way for users to review CAs ahead of
time, or see whether a particular CA will or won't be trusted ahead
of time).  On the other hand, a similar phenomenon occurs in other
browsers with regard to intermediate CAs, because there's no way to
get a list of intermediate CAs before they are encountered in the wild,
and definitely no way to get an exhaustive list of all of the
intermediate CAs that would be trusted.  In fact, in some sense no
one in the entire world is in possession of that list. :-(

Peter Eckersley has produced a list of intermediates which you can
see visualized in


but of course that list derives from a scan from a particular point
in time (and not using SNI); there is no guarantee that there aren't
other intermediate CAs which simply weren't encountered that way
(or even intermediate CAs whose existence is kept a secret and
that are only used in a limited way by particular attackers under
particular circumstances).

Seth Schoen  <schoen at eff.org>
Senior Staff Technologist                       https://www.eff.org/
Electronic Frontier Foundation                  https://www.eff.org/join
454 Shotwell Street, San Francisco, CA  94110   +1 415 436 9333 x107

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