Digital watermarking is a promising solution to video game piracy. In this paper, based on the analysis of special challenges and requirements in terms of watermarking textures in video games, a novel watermarking scheme for DDS textures in video games is proposed. To meet the performance requirements in video game applications, the proposed algorithm embeds the watermark message directly in the compressed stream in DDS files and can be straightforwardly applied in watermark container technique for real-time embedding. Furthermore, the embedding approach achieves high watermark payload to handle collusion secure fingerprinting codes with extreme length. Hence, the scheme is resistant to collusion attacks, which is indispensable in video game applications. The proposed scheme is evaluated in aspects of transparency, robustness, security and performance. Especially, in addition to classical objective evaluation, the visual quality and playing experience of watermarked games is assessed subjectively in game playing.
The publishers of video games suffer from illegal piracy and information leakage caused by end-consumers, "release groups" or insiders shortly after or even before the official release of a new video game. Mechanisms to prevent or at least postpone this illegal redistribution are DRM or copy protection mechanisms. However, these mechanisms are very unpopular, because they restrict the customers in playing the game and demand a high administration effort from the developers and/or distributors. Even worse, most copy protection mechanisms have proven to be insecure as "patches" for circumvention usually are available quickly and easy to get. To satisfy the challenges of security and usability, this work introduces the idea of using digital watermarking to protect all available and suitable media types and software binaries contained in a video game. A three-layered watermarking deployment approach along the production chain is proposed to detect leakage in the release phase as well as during the development process of a boxed video game. The proposed approach features both copyright watermarking and collusion secure fingerprints embedded as transaction watermark messages in components of video games. We discuss the corresponding new challenges and opportunities. In addition, a prototype watermarking algorithm is presented to demonstrate the adaption necessity of classical image watermarking when applied to video games to satisfy the requirements for transparency, security as well as performance. The watermark capacity is significantly increased while inter-media and inter-file embedding is enabled and the associated synchronization challenge is solved by robust hashes.
Forensic analysis of image sets today is most often done with the help of cryptographic hashes due to their efficiency,
their integration in forensic tools and their excellent reliability in the domain of false detection alarms. A drawback of
these hash methods is their fragility to any image processing operation. Even a simple re-compression with JPEG results
in an image not detectable. A different approach is to apply image identification methods, allowing identifying illegal
images by e.g. semantic models or facing detection algorithms. Their common drawback is a high computational
complexity and significant false alarm rates. Robust hashing is a well-known approach sharing characteristics of both
cryptographic hashes and image identification methods. It is fast, robust to common image processing and features low
false alarm rates. To verify its usability in forensic evaluation, in this work we discuss and evaluate the behavior of an
optimized block-based hash.
Robustness against distortions caused by common image processing is one of the essential properties for image
watermarking to be applicable in real-world applications. Typical distortions include lossy JPEG compression, filtering,
cropping, scaling, rotation, and so on, among which geometric distortion is more challenging. Even slight geometric
distortion can totally fail the watermark detection through de-synchronization. Another important property is the
watermark payload. Although one-bit watermark is widely used in research work for algorithm testing and evaluation,
only checking whether a specific watermark exists does not meet the requirement of many practical applications. This
paper presents a practical robust image watermarking algorithm which combines template embedding and patchwork
watermarking in Fourier domain. The embedded template enables the necessary robustness against geometric distortions
and the patchwork approach provides a reasonable watermark payload which can meet the requirement of most
applications. A spatial perceptual mask is used to reshape the embedded energy after it is inverted to the spatial domain,
which significantly improves the image quality and enhances the robustness of both template and watermark.
Implementation issues and solutions, e.g. fine-tuning of embedding energy of individual pixels, are also discussed.
Experimental results demonstrate the effectiveness and practicability of the proposed algorithm.
We present two approaches to robust image obfuscation based on permutation of image regions and channel
intensity modulation. The proposed concept of robust image obfuscation is a step towards end-to-end security in
Web 2.0 applications. It helps to protect the privacy of the users against threats caused by internet bots and web
applications that extract biometric and other features from images for data-linkage purposes. The approaches
described in this paper consider that images uploaded to Web 2.0 applications pass several transformations, such
as scaling and JPEG compression, until the receiver downloads them. In contrast to existing approaches, our
focus is on usability, therefore the primary goal is not a maximum of security but an acceptable trade-off between
security and resulting image quality.
Multimedia forensics deals with the analysis of multimedia data to gather information on its origin and authenticity. One
therefore needs to distinguish classical criminal forensics (which today also uses multimedia data as evidence) and
multimedia forensics where the actual case is based on a media file. One example for the latter is camera forensics where
pixel error patters are used as fingerprints identifying a camera as the source of an image. Of course multimedia forensics
can become a tool for criminal forensics when evidence used in a criminal investigation is likely to be manipulated. At
this point an important question arises: How reliable are these algorithms? Can a judge trust their results? How easy are
they to manipulate? In this work we show how camera forensics can be attacked and introduce a potential
countermeasure against these attacks.
Changing the distribution channel of movies from analogue to digital provides new perspectives and possibilities for
applying digital watermarking as security mechanisms. Digital watermarking provides its best security options when
used for individual marking of copies to trace back distribution leaks. For analogue copies, protecting movies with
individual watermarks was only cost-effective for small sets of copies as in promotional copies as duplication is done in
an automated photo-optical way. Modifications of the analogue copies only provide relatively crude approaches of
individual marking. Digital copies on the other hand can easily be modified before, during or even after distribution to
cinemas. It is also possible to embed watermarks at all of these stages to secure the complete distribution chain from
studio to cinema. In our paper we discuss two watermarking strategies suitable for different applications in the digital
cinema domain, video and still image watermarking. We provide technical background and also discuss the interference
of applying both algorithms at the same time.
In our paper we discuss and compare the possibilities and shortcomings of both content-fragile watermarking and
digital forensics and analyze if the combination of both techniques allows the identification of more than the sum
of all manipulations identified by both techniques on their own due to synergetic effects. The first part of the
paper discusses the theoretical possibilities offered by a combined approach, in which forensics and watermarking
are considered as complementary tools for data authentication or deeply combined together, in order to reduce
their error rate and to enhance the detection efficiency. After this conceptual discussion the paper proposes
some concrete examples in which the joint approach is applied to video authentication. Some specific forensics
techniques are analyzed and expanded to handle efficiently video data. The examples show possible extensions
of passive-blind image forgery detection to video data, where the motion and time related characteristics of video
are efficiently exploited.
MPEG-4 is an international object-based standard that provides technological basis for digital television, interactive graphics and multimedia applications. These objects can be natural or synthetic e.g. textures, 3D objects, videos or sounds. In this paper we suggest an integrity approach to protect the content of MPEG-4 data. The essential part of this approach is to embed a robust watermark into each visual, audio and 3D object. The content fragile watermark verifying the integrity of a scene is the sum of all information retrieved from the robust watermarks extracted from the objects of the scene. The information of the fragile watermark will be distributed redundantly to all robust watermarks of the scene. Another essential part of our approach is to embed a part of the scene description or object descriptors as a watermark message into the video or audio streams. The amount of embedded information depends on the payload of the watermarking algorithms. We also analyze the possibility of embedding equivalent information into 3D models, depending on the application.
In this paper, a wavelet domain robust watermarking technique for still images is presented. Watermark message encoding is accomplished based on iterative error correction codes with reasonable decoder complexity, followed by the codeword spreading over the whole image. Unlike the traditional technique, the proposed method utilizes the statistical property of a certain local area of an image in DWT domain for the watermark embedding and extraction. To minimize the perceptual degradation of the watermarked image, we propose an image compensation strategy (ICS) to make the watermark perceptually invisible. Experimental results demonstrate the robustness of the algorithm to many attacks, such as A/D and D/A processing, rescaling, and lossy compression.