| Popis: |
Protection of intellectual property is a well re- searched area of computer science. There are many methods that allow securing information that should not be available to unauthorized parties. Many of these techniques provide protection on a relatively low level such as file encryption or filtering of network traffic. However, many of the mechanisms fail as soon as someone attempts to save the content of the screen that is displaying the sensitive data. Such a malicious insider can cause serious harm to an organization's reputation and finances. It is important in case of such incidents to be able to track the source of the leak. In this paper a method for watermarking the screen image, that can be used in forensic investigations, is presented. The imperceptible digital watermark is placed on the overlay layer over the whole computer screen. Our method leverages the Human Visual System (HVS) properties and allows to generate dynamically adaptable watermarks that respond to the currently displayed content by using the FAST feature detection algorithm. We use QR Codes that provide spatial non-uniformity and error correction capabilities. The evaluation shows that our scheme works well in the selected use-case scenarios. We show that the watermark is robust against modifications typical for office processing, such as cropping and quality preserving JPEG compression. Keywords -real-time digital watermarking, overlaying layer, screenshot protection, malicious insider, digital forensic. |
