[liberationtech] Removing watermarks from pdfs (pdfparanoia)

Ted Smith tedks at riseup.net
Wed Feb 6 06:53:58 PST 2013

On Wed, 2013-02-06 at 08:48 +0100, Eugen Leitl wrote:
> I get PDFs watermarked to me by their placement of sections in
> relation
> to one another, their word choice in opening sentences of paragraphs,
> and figure/image locations within the PDF. The idea being that the
> content is the watermark, not some silly overlay watermark which is
> fairly easily stripped out in most free operating systems.


Permuting word choice in opening sentences seems like a way more
resource intensive way of doing things than most journal publishers
could do -- especially since the source materials are a mix of Word and

I wonder if this is because Andrew gets PDFs from government agency-type
places, as a Tor Project staff member.

This is scary from a leaker's perspective -- you'd have to get two (or
more) different copies of any given watermarked document and merge them
in some way to obfuscate the original source.

Sent from Ubuntu

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