[cryptography] Which encryption chips are compromised?

Marcus Brinkmann marcus.brinkmann at ruhr-uni-bochum.de
Thu Dec 12 05:54:44 EST 2013

On 12/12/2013 08:41 AM, coderman wrote:
> On Wed, Dec 11, 2013 at 9:15 PM, Andy Isaacson <adi at hexapodia.org> wrote:
>> ...  Since the source document appears to be the same
>> for both, an enterprising DTP jockey could use -clean-1.pdf to tune the
>> document settings precisely, and then use -project.pdf to search for
>> better unredaction matches.
> i remember seeing software to do this, but for the life of me cannot
> find it.  anyone?

I only remember this news item from Eurocrypt 2004:


Eurocrypt 2004 rump Session,
David Naccache and Claire Whelan,
9/11: Who alerted the CIA? (And Other Secret Secrets)

The basic technique is simple enough, although writing a toolbox that 
can accomodate the various fonts, languages etc is probably plenty of work.

> my favorite redaction technique is still the Adobe white text on white
> background in PDF trick; combine with a filter for CONFIDENTIAL /
> PROPRIETARY and you've got a fire hose of informative flotsam...[0]

Yes, for example 
https://www.schneier.com/blog/archives/2005/05/pdf_radacting_f.html (the 
internet sources cited by Schneier start to detoriate, though).

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