391
Screen Watermarking for
Data Theft Investigation
and Attribution
Abstract: Organizations not only need to defend their IT systems against external
cyber attackers, but also from malicious insiders, that is, agents who have inltrated
an organization or malicious members stealing information for their own prot. In
particular, malicious insiders can leak a document by simply opening it and taking
pictures of the document displayed on the computer screen with a digital camera.
Using a digital camera allows a perpetrator to easily avoid a log trail that results from
using traditional communication channels, such as sending the document via email.
This makes it difcult to identify and prove the identity of the perpetrator. Even a
policy prohibiting the use of any device containing a camera cannot eliminate this
threat since tiny cameras can be hidden almost everywhere.
To address this leakage vector, we propose a novel screen watermarking technique
that embeds hidden information on computer screens displaying text documents. The
watermark is imperceptible during regular use, but can be extracted from pictures
of documents shown on the screen, which allows an organization to reconstruct the
David Gugelmann
1
ETH Zurich
Zurich, Switzerland
david.gugelmann@alumni.ethz.ch
Vincent Lenders
armasuisse
Thun, Switzerland
vincent.lenders@armasuisse.ch
Laurent Vanbever
ETH Zurich
Zurich, Switzerland
lvanbever@ethz.ch
David Sommer
1
ETH Zurich
Zurich, Switzerland
Markus Happe
ETH Zurich
Zurich, Switzerland
markus.happe@alumni.ethz.ch
2018 10th International Conference on Cyber Conict
CyCon X: Maximising Eects
T. Minárik, R. Jakschis, L. Lindström (Eds.)
2018 © NATO CCD COE Publications, Tallinn
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use within NATO and for personal or educational use when for non-prot or
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requires prior written permission by NATO CCD COE.
1
equally contributing authors
