Visible to the public Screen watermarking for data theft investigation and attribution

TitleScreen watermarking for data theft investigation and attribution
Publication TypeConference Paper
Year of Publication2018
AuthorsGugelmann, D., Sommer, D., Lenders, V., Happe, M., Vanbever, L.
Conference Name2018 10th International Conference on Cyber Conflict (CyCon)
Date Publishedmay
Keywordsattribution, Cameras, composability, Computer crime, computer security, cropped compressed pictures, data compression, data encapsulation, data leakage, data mining, data theft, data theft attribution, data theft investigation, digital camera, digital cameras, external cyber attackers, Human Behavior, human eye, human-in-the-loop security center paradigm, Image coding, Image color analysis, image watermarking, infiltration, investigation, malicious insiders, malicious members, Metrics, Organizations, pubcrawl, recovered leaked pictures, screen watermarking, screen watermarks, symbol shape, text documents, Watermarking
AbstractOrganizations not only need to defend their IT systems against external cyber attackers, but also from malicious insiders, that is, agents who have infiltrated an organization or malicious members stealing information for their own profit. 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 difficult 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 place and time of the data leak from recovered leaked pictures. Our approach takes advantage of the fact that the human eye is less sensitive to small luminance changes than digital cameras. We devise a symbol shape that is invisible to the human eye, but still robust to the image artifacts introduced when taking pictures. We complement this symbol shape with an error correction coding scheme that can handle very high bit error rates and retrieve watermarks from cropped and compressed pictures. We show in an experimental user study that our screen watermarks are not perceivable by humans and analyze the robustness of our watermarks against image modifications.
Citation Keygugelmann_screen_2018