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Building Covert Channels over the Packet Reordering Phenomenon
"... New modes of communication have shown themselves to be needed for more secure and private types of data. Steganography or datahiding through covert channels can be highly motivated by today’s security requirements and various needs of applications. Moreover, the amount of information in the Intern ..."
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New modes of communication have shown themselves to be needed for more secure and private types of data. Steganography or datahiding through covert channels can be highly motivated by today’s security requirements and various needs of applications. Moreover, the amount of information in the Internet traffic is not bounded by what is contained in packets payload; there is considerable hidden capacity within packets and flows characteristics to build robust and stealthy covert channels. In this paper, we propose using the packet reordering phenomenon as the media to carry a hidden channel. As a naturally occurring behavior of packets traveling the Internet, it can as well be induced to send a signal to the receiving end. Specific permutations are selected to enhance the reliability of the channel, while their distribution was selected to imitate real traffic and increase stealthiness. The robustness of such channel is analyzed, and its bandwidth is calculated. A simple tool is implemented to communicate over the natural phenomenon of packet reordering. Reliability and capacity of the techniques are evaluated and promising results show the potential of the proposed approach.
Practical DataHiding: Additive Attacks Performance Analysis
 In International Workshop on Digital Watermarking, volume LNCS 3710 of Lecture Notes in Computer Science
, 2005
"... The main goal of this tutorial is to review the theory and design the worst case additive attack (WCAA) for Mary quantizationbased datahiding methods using as performance criteria the error probability and the maximum achievable rate of reliable communications. Our analysis focuses on the pr ..."
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The main goal of this tutorial is to review the theory and design the worst case additive attack (WCAA) for Mary quantizationbased datahiding methods using as performance criteria the error probability and the maximum achievable rate of reliable communications. Our analysis focuses on the practical scheme known as distortion compensation dither modulation (DCDM). From the mathematical point of view, the problem of the worst case attack (WCA) design using probability of error as a cost function is formulated as the maximization of the average probability of error subject to the introduced distortion for a given decoding rule. When mutual information is selected as a cost function, a solution to the minimization problem should provide such an attacking noise probability density function (pdf) that will maximally decrease the rate of reliable communications for an arbitrary decoder structure.
Published By: Blue Eyes Intelligence Engineering
"... AbstractSecure transmission of message between the sender and receiver is carried out through a tool called as cryptography. Traditional cryptographical methods use either public key which is known to everyone or on the private key. In either case the eavesdroppers are able to detect the key and he ..."
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AbstractSecure transmission of message between the sender and receiver is carried out through a tool called as cryptography. Traditional cryptographical methods use either public key which is known to everyone or on the private key. In either case the eavesdroppers are able to detect the key and hence find the message transmitted without the knowledge of the sender and receiver. Quantum cryptography is a special form of cryptography which uses the Quantum mechanics to ensure unconditional security towards the transmitted message. Quantum cryptography uses the distribution of random binary key known as the Quantum Key Distribution (QKD) and hence enables the communicating parties to detect the presence of potential eavesdropper. This paper also analyses few application areas of quantum cryptography and its limitations.
PG Student
"... Abstract — In this paper we present a low frequency watermarking scheme on gray level images, which is based on DCT transform and spread spectrum communications technique.The DCT of non overlapping 8x8 blocks of the host image is computed, then using each block DC coefficients we construct a lowres ..."
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Abstract — In this paper we present a low frequency watermarking scheme on gray level images, which is based on DCT transform and spread spectrum communications technique.The DCT of non overlapping 8x8 blocks of the host image is computed, then using each block DC coefficients we construct a lowresolution approximation image. We apply block based DCT on this approximation image, then a pseudo random noise sequence is added into its high frequencies. For detection, we extract the approximation image from the watermarked image, then the same pseudo random noise sequence is generated, and its correlation is computed with high frequencies of the watermarked approximation image. In our method, higher robustness is obtained because of embedding the watermark in low frequency. In addition, higher imperceptibility is gained by scattering the watermark's bit in different blocks. We evaluated the robustness of the proposed technique against many common attacks such as JPEG compression, additive Gaussian noise and median filter. Compared with related works, our method proved to be highly resistant in cases of compression and additive noise, while preserving high PSNR for the watermarked images.
Practical DataHiding: Additive Attacks Performance Analysis
"... The main goal of this tutorial is to review the theory and design the worst case additive attack (WCAA) for ∣M∣ary quantizationbased datahiding methods using as performance criteria the error probability and the maximum achievable rate of reliable communications. Our analysis focuses on the pract ..."
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The main goal of this tutorial is to review the theory and design the worst case additive attack (WCAA) for ∣M∣ary quantizationbased datahiding methods using as performance criteria the error probability and the maximum achievable rate of reliable communications. Our analysis focuses on the practical scheme known as distortion compensation dither modulation (DCDM). From the mathematical point of view, the problem of the worst case attack (WCA) design using probability of error as a cost function is formulated as the maximization of the average probability of error subject to the introduced distortion for a given decoding rule. When mutual information is selected as a cost function, a solution to the minimization problem should provide such an attacking noise probability density function (pdf) that will maximally decrease the rate of reliable communications for an arbitrary decoder structure. The obtained results demonstrate that, within the class of additive attacks, the developed attack leads to a stronger performance decrease for the considered class of embedding techniques than the additive white Gaussian or [...]