DRM Shoots Itself in the Foot, episode... oh, many

Lets say you've been tasked with implementing a DRM system. 
So you go to the
Digital Content Protection LLC site and download the HDCP
spec, which contains
all the test vectors, sample keys, and whatnot, that you
need for HDCP.

However, since it's from Digital Content Protection LLC, the
docs are DRM'd
(PDF-protected from copying).  So you can eyeball the key
tables and test
vectors that you need to implement the DRM, you just can't
use them.

DRM, helping prevent... DRM.

Peter.

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There are pdf viewers and pdf image and text extraction
tools for
various platforms that allow you to extract content despite
the
document Security Methods specification of Document
Restrictions. 
Failing that you could always do screen grabs and Optical
Character
Recognition.

DRM failing because they let people actually see their
super-Sekrets.

Saw a fun one recently, watermarks whose text becomes opaque
after
printing once.  Gee, you make the file ugo-w, or should you
start
looking out for signs of a root kit?

D.



--- Peter Gutmann <pgut001cs.auckland.ac.nz>
wrote:

> Lets say you've been tasked with implementing a DRM
system.  So you
> go to the
> Digital Content Protection LLC site and download the
HDCP spec, which
> contains
> all the test vectors, sample keys, and whatnot, that
you need for
> HDCP.
> 
> However, since it's from Digital Content Protection
LLC, the docs are
> DRM'd
> (PDF-protected from copying).  So you can eyeball the
key tables and
> test
> vectors that you need to implement the DRM, you just
can't use them.
> 
> DRM, helping prevent... DRM.
> 
> Peter.
> 
>
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> The Cryptography Mailing List
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> majordomometzdowd.com
> 

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