WindTalker: An Efficient and Robust Protocol of Cloud Covert Channel Based on Memory Deduplication

AbstractClassical or traditional steganography aims at hiding a secret in cover media such as text, image, audio, video or even in network protocols. Recent research has improved this approach called distributed steganography by fragmenting the secret message and embedding each secret piece into a distinct cover media. The major interest of this approach is to make the secret message detection extremely difficult. However, these file modifications leave fingerprints which can reveal a secret channel to an attacker. Our contribution is a new steganography paradigm transparent to any attacker and resistant to the detection and the secret extraction. Two properties contribute to achieve these goals: the files do not undergo any modification while the distribution of the secret in the multi-cloud storage environment allows us to hide the existence of the covert channel between the communicating parties. Information’s are usually hidden inside the cover media. In this work, the covert media is a pointer to information. Therefore the file carries the information without being modified and the only way to access it is to have the key. Experiments show interesting comparison results with remarkable security contributions. The work can be seen as a new open direction for further research in the field.

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A cookbook for DNase Hi-C

Epigenetics & Chromatin ◽

10.1186/s13072-021-00389-5 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Maria Gridina ◽

Evgeniy Mozheiko ◽

Emil Valeev ◽

Ludmila P. Nazarenko ◽

Maria E. Lopatkina ◽

...

Keyword(s):

Rational Design ◽

Restriction Enzymes ◽

Nucleotide Exchange ◽

Computational Tools ◽

3 Dimensional ◽

Cultured Human Cells ◽

Dna Ends ◽

By Products ◽

Robust Protocol

Abstract Background The Hi-C technique is widely employed to study the 3-dimensional chromatin architecture and to assemble genomes. The conventional in situ Hi-C protocol employs restriction enzymes to digest chromatin, which results in nonuniform genomic coverage. Using sequence-agnostic restriction enzymes, such as DNAse I, could help to overcome this limitation. Results In this study, we compare different DNAse Hi-C protocols and identify the critical steps that significantly affect the efficiency of the protocol. In particular, we show that the SDS quenching strategy strongly affects subsequent chromatin digestion. The presence of biotinylated oligonucleotide adapters may lead to ligase reaction by-products, which can be avoided by rational design of the adapter sequences. Moreover, the use of nucleotide-exchange enzymes for biotin fill-in enables simultaneous labelling and repair of DNA ends, similar to the conventional Hi-C protocol. These improvements simplify the protocol, making it less expensive and time-consuming. Conclusions We propose a new robust protocol for the preparation of DNAse Hi-C libraries from cultured human cells and blood samples supplemented with experimental controls and computational tools for the evaluation of library quality.

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Statistical Evaluation of Total Expiratory Breath Samples Collected throughout a Year: Reproducibility and Applicability toward Olfactory Sensor-Based Breath Diagnostics

Sensors ◽

10.3390/s21144742 ◽

2021 ◽

Vol 21 (14) ◽

pp. 4742

Author(s):

Katsushige Inada ◽

Hiroshi Kojima ◽

Yukiko Cho-Isoda ◽

Ryo Tamura ◽

Gaku Imamura ◽

...

Keyword(s):

Statistical Evaluation ◽

Target Material ◽

Health Condition ◽

Exhaled Breath ◽

Humidity Effects ◽

Signal Features ◽

Volatile Organic ◽

Olfactory Systems ◽

Membrane Type ◽

Robust Protocol

The endogenous volatile organic compounds (VOCs) in exhaled breath can be promising biomarkers for various diseases including cancers. An olfactory sensor has a possibility for extracting a specific feature from collective variations of the related VOCs with a certain health condition. For this approach, it is important to establish a feasible protocol for sampling exhaled breath in practical conditions to provide reproducible signal features. Here we report a robust protocol for the breath analysis, focusing on total expiratory breath measured by a Membrane-type Surface stress Sensor (MSS), which possesses practical characteristics for artificial olfactory systems. To assess its reproducibility, 83 exhaled breath samples were collected from one subject throughout more than a year. It has been confirmed that the reduction of humidity effects on the sensing signals either by controlling the humidity of purging room air or by normalizing the signal intensities leads to reasonable reproducibility verified by statistical analyses. We have also demonstrated the applicability of the protocol for detecting a target material by discriminating exhaled breaths collected from different subjects with pre- and post-alcohol ingestion on different occasions. This simple yet reproducible protocol based on the total expiratory breath measured by the MSS olfactory sensors will contribute to exploring the possibilities of clinical applications of breath diagnostics.

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