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Re: Research on better-than-brute-force attacks on PDF cryptography
From: Dhiru Kholia <dhiru.kholia () gmail com>
Date: Sun, 22 Sep 2013 22:53:02 +0530
On 09/17/13 at 08:26pm, Florian Weimer wrote:
I've looked at a PDF implementation, compared it against the specification
(including Adobe's supplement covering AES-256), and unless I'm missing
something, there are a few odd things there.
Does anyone know if there's published research into this topic? I could
only find indications that the specification does not adequately defend
against brute-force password guessing. Which is probably true, but not
exactly my concern.
http://tinyurl.com/pdf-fmt-plug-c might help you in your research.
For unknown reasons, Adobe weakened their "KDF" in the "R5" scheme, a
mistake which they have fixed in their current "R6" scheme.