Independent component analysis for domain independent watermarking

A new principled domain independent watermarking framework is presented. The new approach is based on embedding the message in statistically independent sources of the covertext to mimimise covertext distortion, maximise the information embedding rate and improve the method's robustness against various attacks. Experiments comparing the performance of the new approach, on several standard attacks show the current proposed approach to be competitive with other state of the art domain-specific methods

Extraction of green absolute from thyme using ultrasound and sunflower oil

Absolute is the plant aroma isolate mostly used in the food and fragrance sectors. The use of organic solvents constitutes the most commonly used method for obtaining this aroma. However, this technique may leave trace amounts of solvents which are considered undesirable for these industries. In this work, a new green extraction approach was implemented using ultrasound (US) with sunflower oil (SO) as a natural solvent to produce green absolute from thyme (Thymus vulgaris). US optimal conditions for absolute yield were investigated using response surface methodology (RSM) and compared to conventional SO (SO-CV) and hexane (Hex-CV) extractions. The absolutes were analyzed by GC-MS for their chemical composition and tested for their antioxidant activities (total phenols, DPPH and frying test). Optimized conditions obtained by RSM for absolute yield were T = 50 °C, t = 22 min, P = 98 W. The US using SO as solvent offers important advantages: shorter extraction time, increase of 47% in absolute yield compared to SO-CV extraction. Although the absolute obtained by hexane extraction provided improved yield (8.64 g/100 g DW), it contained around 75% of waxy materials. GC-MS analysis showed no remarkable variation of the chemical composition of the absolutes compared to those obtained by hexane extraction. Moreover, the US extraction allowed the highest recovery of monoterpene phenols thymol and carvacrol (86.2%). The absolute obtained by SO-US was free from waxes and organic solvent residues and exerted the highest antioxidant activity. Results show that ultrasound extraction using SO is a good alternative. It suggests the possibility of the production of green absolutes on pilot and industrial scale

CamouflageFS: Increasing the Effective Key Length in Cryptographic Filesystems on the Cheap

One of the few quantitative metrics used to evaluate the security of a cryptographic file system is the key length of the encryption algorithm; larger key lengths correspond to higher resistance to brute force and other types of attacks. Since accepted cryptographic design principles dictate that larger key lengths also impose higher processing costs, increasing the security of a cryptographic file system also increases the overhead of the underlying cipher. We present a general approach to effectively extend the key length without imposing the concomitant processing overhead. Our scheme is to spread the ciphertext inside an artificially large file that is seemingly filled with random bits according to a key-driven spreading sequence. Our prototype implementation, CamouflageFS, offers improved performance relative to a cipher with a larger key-schedule, while providing the same security properties. We discuss our implementation (based on the Linux Ext2 file system) and present some preliminary performance results. While CamouflageFS is implemented as a stand-alone file system, its primary mechanisms can easily be integrated into existing cryptographic file systems

Automatic evaluation of watermarking schemes

Many watermarking schemes are now well defined, but it is still very difficult to compare them and thus find the one which fits our needs. Since both media and attacks used for evaluation are different in each article, it is almost impossible to compare the schemes.In this article, we introduce StirMark Benchmark 4, a new automatic tool to evaluate watermarking schemes. It is written in C++, according to an object oriented model, which allows us towork on images and audio files.There are many different applications for watermarking, so we use profiles to define tests to apply according to the requested parameters of the method, and its purposes. We also propose different levels of quality on usual criteria (perceptibility, robustness and capacity) to increase the legibility of the performances obtained by the schemes. We also introduce new tests (audio, key space, falsealarms, multiple watermarking).Les méthodes de tatouage sont de plus en plus nombreuses. Néanmoins, il est difficile de les comparer et de trouver celle adaptée à ses besoins dans la mesure où les tests présentés sont très souvent différents. En effet, tant les média employés que les transformations qu'ils subissent changent d'une étude à l'autre. Dans cet article, nous présentons StirMark Benchmark 4, un outil d'évaluation automatique pour les schémas de tatouage. Il est développé en C++, selon un modèle orienté objets, ce qui nous a permis de l'adapter à la fois aux images et aux fichiers audios. Les algorithmes de tatouage étant tous dissemblables, nous utilisons des profils qui définissent les tests à appliquer aux méthodes, selon les paramètres dont elles se servent et les objectifs poursuivis. Nous proposons également des niveaux d'assurance sur les critères habituels (perceptibilité, robustesse et capacité) afin de faciliter la lisibilité des performances obtenues par les schémas. Nous présentons aussi de nouveaux tests (audio, espace des-clés, fausses alarmes, marquage multiple)

OR-Benchmark: An Open and Reconfigurable Digital Watermarking Benchmarking Framework

Benchmarking digital watermarking algorithms is not an easy task because different applications of digital watermarking often have very different sets of requirements and trade-offs between conflicting requirements. While there have been some general-purpose digital watermarking benchmarking systems available, they normally do not support complicated benchmarking tasks and cannot be easily reconfigured to work with different watermarking algorithms and testing conditions. In this paper, we propose OR-Benchmark, an open and highly reconfigurable general-purpose digital watermarking benchmarking framework, which has the following two key features: 1) all the interfaces are public and general enough to support all watermarking applications and benchmarking tasks we can think of; 2) end users can easily extend the functionalities and freely configure what watermarking algorithms are tested, what system components are used, how the benchmarking process runs, and what results should be produced. We implemented a prototype of this framework as a MATLAB software package and demonstrate how it can be used in three typical use cases. The first two use cases show how easily we can define benchmarking profiles for some robust image watermarking algorithms. The third use case shows how OR-Benchmark can be configured to benchmark some image watermarking algorithms for content authentication and self-restoration, which cannot be easily supported by other digital watermarking benchmarking systems

Revisiting software protection

We provide a selective survey on software protection, including approaches to software tamper resistance, obfuscation, software diversity, and white-box cryptography. We review the early literature in the area plus recent activities related to trusted platforms, and discuss challenges and future directions