[Cryptography] NSA and cryptanalysis

Perry E. Metzger perry at piermont.com
Mon Sep 2 18:55:44 EDT 2013

On Mon, 2 Sep 2013 17:44:57 -0400 Jerry Leichter <leichter at lrw.com>
> > ...Clearly, as things like bad vendor drivers updates have been
> > sent out using stolen keys in the past, and clearly vendors might
> > simply make mistakes in the future....
> Except that that's not what happened in this case.
> Someone took an old, valid Microsoft license - which should never

Yes, certainly, but the end effect was that an untrustworthy piece of
code was then executing on the victim's machine. That can be happen
by many means, however, both intentional and accidental -- trojan
horses, vendor mistakes, bugs, rogue employees at a vendor, a vendor's
credentials being stolen, cryptographic breaks like this, etc.

Now, I do indeed find it interesting and exotic that someone involved
knows how to create MD5 collisions by a different method than we know
of in the open literature, and that tickles my fancy as a
person who loves cryptography, and probably tells us something about
who wrote that particular exploit.

What it does not do, however, is tell me much about how to
make systems robust against the wide variety of reasons why
untrustworthy software might appear on a machine.

As a security person, it is this latter problem that is vital
to me, since doubtless that will show up again in the future. Even
ignoring malice, bugs often happen in device drivers and other code
running in security critical environments like kernels.

I will again mumble things like: "typed assembly language, proof
carrying code, microkernels, hardware assists, formal verification..."
in the hopes that the mumbling might set some minds thinking.

Perry E. Metzger		perry at piermont.com

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