In digital media transfer, geometrical transformations desynchronize the communications between t... more In digital media transfer, geometrical transformations desynchronize the communications between the encoder and the decoder. Therefore, an attempt to decode the message based on the direct output of the channel with random geometrical state fails. The main goal of this paper is to analyze the conditions of reliable communications based on structured codebooks in channels with geometrical transformations. Structured codebooks include codewords that have some features or statistics designed for synchronization purposes. In the design of capacity approaching data-hiding codes, host interference problem should be resolved. The solution to this problem is to perform the message coding based on random binning dependent on host-state. On the other hand, to achieve robustness to geometrical transformations, the codewords should have host independent statistics and encoding should be performed using random coding. To satisfy these conflicting requirements we propose Multiple Access Channel (MAC) framework where the message is split between two encoders designed based on the random binning and random coding principles. The message encoded according to random coding additionally serves for synchronization purposes. Sequentially, all existing methods that are proposed for reliable communications in channels with geometrical transformations are analyzed within the proposed MAC set-up. Depending on the particular codebook design, we classify these methods into two main groups: template-based codebooks and redundant codebooks. Finally, we perform the analysis of security leaks of each codebook structure in terms of complexity of the worst case attack.
Periodical watermark embedding has been especially proposed to cope with geometrical attacks. Usi... more Periodical watermark embedding has been especially proposed to cope with geometrical attacks. Using a diversity approach, this method allows to decrease the probability of error in the case of additive attacks. It is usually admitted that the worst additive attack consists in the addition of additive white Gaussian noise (AWGN). However, our theoretical capacity analysis of periodical watermarking demonstrates that periodical AWGN in the optimal attacking strategy leads to more significant drop of the capacity than AWGN test channel from rate distortion.
In this paper we analyze security of robust data-hiding in channels with geometrical transformati... more In this paper we analyze security of robust data-hiding in channels with geometrical transformations. We categorize possible decoding strategies for channels with geometrical transformations within the information-theoretic framework for geometrically-robust datahiding. Furthermore, considering template-based and redundantbased design of geometrically robust data-hiding systems, we provide the analysis of general attacking strategies and particular attacking scenarios for each group of structured codebooks. Finally, reversibility of data-hiding and effect of security leakages on system performance are investigated.
In this paper we present a feasibility study of printed document forensics based on steganographi... more In this paper we present a feasibility study of printed document forensics based on steganographic anti-counterfeiting markings using portable devices. We propose two system architectures and analyze their pros and contres for mass usage. Furthermore, we perform an analysis of the probability of error that can be attained in the system based on steganographic anti-counterfeiting markings and explicit the conditions to reach reliable performance.
Geometrical transformations bring synchronization problems into the robust digital data-hiding. P... more Geometrical transformations bring synchronization problems into the robust digital data-hiding. Previous works on this subject were concentrated on the robustness to particular geometrical transformations. In this paper, the achievable rates of reliable robust data-hiding in channels with geometrical transformations are investigated from an informationtheoretic point of view for theoretical set-ups, where lengths of data sequences asymptotically approach infinity.
In this paper, we analyze the reversibility of data hiding techniques based on random binning as ... more In this paper, we analyze the reversibility of data hiding techniques based on random binning as a by-product of pure message communications. We demonstrate the capabilities of unauthorized users to perform hidden data removal using solely a signal processing approach based on optimal estimation as well as consider reversibility on the side of authorized users who have knowledge of the key used for the message hiding. In fact, we show that knowledge of the auxiliary random variable, used in the codebook construction of random binning techniques, is sufficient to perform the optimal reversibility procedure. We compare the optimal rate-distortion region results obtained using more involved coding strategies based on hybrid random binning with those utilizing uncoded transmission. This analysis is performed for the generalized Gel'fand-Pinsker formulation, Gaussian Costa setup and particular practical schemes based on structured codebooks. Finally, we consider some related open issues and possible future extensions.
In this paper we consider the problem of document authentication in electronic and printed forms.... more In this paper we consider the problem of document authentication in electronic and printed forms. We formulate this problem from the information-theoretic perspectives and present the joint source-channel coding theorems showing the performance limits in such protocols. We analyze the security of document authentication methods and present the optimal attacking strategies with corresponding complexity estimates that, contrarily to the existing studies, crucially rely on the information leaked by the authentication protocol. Finally, we present the results of experimental validation of the developed concept that justifies the practical efficiency of the elaborated framework.
In this work, we consider the text data-hiding problem as a particular instance of the well-known... more In this work, we consider the text data-hiding problem as a particular instance of the well-known Gel’fand-Pinsker problem [1]. The text, where some message \(m \in \mathcal{M}\) is to be hidden, is represented by x and called cover text. Each component x i , i = 1, 2, ..., N, of x represents one character from this text. Here, we define a character as an element from a given language alphabet (e.g. the latin alphabet {A, B, ..., Z}). To be more precise, we conceive each character x i as a data structure consisting of multiple component fields (features): name, shape, position, orientation, size, color, etc.
In this paper, we analyze a possibility of reversibility of data-hiding techniques based on rando... more In this paper, we analyze a possibility of reversibility of data-hiding techniques based on random binning from multimedia perspectives. We demonstrate the capabilities of unauthorized users to perform hidden data removal using solely a signal processing approach based on optimal estimation as well as consider reversibility on the side of authorized users who have the knowledge of key used for the message hiding.
Reversibility of data-hiding refers to the reconstruction of original host data at the decoder fr... more Reversibility of data-hiding refers to the reconstruction of original host data at the decoder from the stego data. Previous works on the subject are concentrated on the reversibility of data-hiding techniques from multimedia perspectives. However, from the security point of view, that at our knowledge was not exploited in existing studies, reversibility could be used by an attacker to remove the complete trace of watermark data from the stego data in the sense of designing the worst case attack. Thus, the aim of this paper is to analyze the reversibility of data-hiding techniques based on random binning from the security perspectives.
In this paper we analyze performance of practical robust data-hiding in channels with geometrical... more In this paper we analyze performance of practical robust data-hiding in channels with geometrical transformations. By applying information-theoretic argument we show that performance of a system designed based on both random coding and random binning principles is bounded by the same maximal achievable rate for the cases when communication channel includes geometrical transformations or not. Targeting to provide theoretic performance limits of practical robust data-hiding we model it using a multiple access channel (MAC) with side information (SI) available at one of encoders and present the bounds on achievable rates of reliable communications to such a protocol. Finally, considering template-based and redundant-based design of geometrically robust data-hiding systems, we perform security analysis of their performance and present results in terms of number of trial efforts the attacker needs to completely remove hidden information.
In this paper, we consider the problem of pure information transmission and channel state estimat... more In this paper, we consider the problem of pure information transmission and channel state estimation via state dependent channels. We show that the knowledge of auxiliary random variable, used in the codebook construction of random binning techniques, is sufficient to perform the optimal channel state estimation. We compare the obtained results with optimal rate-distortion region obtained using more involved coding strategies based on hybrid random binning and uncoded transmission. This analysis is performed for the generalized Gel'fand-Pinsker formulation and Gaussian Costa setup.
In this paper, we propose a new theoretical framework for the data-hiding problem of digital and ... more In this paper, we propose a new theoretical framework for the data-hiding problem of digital and printed text documents. We explain how this problem can be seen as an instance of the well-known Gel'fand-Pinsker problem. The main idea for this interpretation is to consider a text character as a data structure consisting of multiple quantifiable features such as shape, position, orientation, size, color, etc. We also introduce color quantization, a new semi-fragile text data-hiding method that is fully automatable, has high information embedding rate, and can be applied to both digital and printed text documents. The main idea of this method is to quantize the color or luminance intensity of each character in such a manner that the human visual system is not able to distinguish between the original and quantized characters, but it can be easily performed by a specialized reader machine. We also describe halftone quantization, a related method that applies mainly to printed text documents. Since these methods may not be completely robust to printing and scanning, an outer coding layer is proposed to solve this issue. Finally, we describe a practical implementation of the color quantization method and present experimental results for comparison with other existing methods. * The concept of strong typicality is nicely introduced in the book by Cover and Thomas 8 † Usually, in the context of data-hiding, a secret key K is shared between both encoder and decoder. The secret key K is used for security purposes. For the sake of completeness explicitly shows the secret key K. However, since in this paper we do not perform a security analysis, we will not refer to it.
In this paper, we analyze a possibility of reversibility of datahiding techniques based on random... more In this paper, we analyze a possibility of reversibility of datahiding techniques based on random binning from multimedia perspectives. We demonstrate the capabilities of unauthorized users to perform hidden data removal using solely a signal processing approach based on optimal estimation as well as consider reversibility on the side of authorized users who have the knowledge of key used for the message hiding.
In digital media transfer, geometrical transformations desynchronize the communications between t... more In digital media transfer, geometrical transformations desynchronize the communications between the encoder and the decoder. Therefore, an attempt to decode the message based on the direct output of the channel with random geometrical state fails. The main goal of this paper is to analyze the conditions of reliable communications based on structured codebooks in channels with geometrical transformations. Structured codebooks include codewords that have some features or statistics designed for synchronization purposes. In the design of capacity approaching data-hiding codes, host interference problem should be resolved. The solution to this problem is to perform the message coding based on random binning dependent on host-state. On the other hand, to achieve robustness to geometrical transformations, the codewords should have host independent statistics and encoding should be performed using random coding. To satisfy these conflicting requirements we propose Multiple Access Channel (MAC) framework where the message is split between two encoders designed based on the random binning and random coding principles. The message encoded according to random coding additionally serves for synchronization purposes. Sequentially, all existing methods that are proposed for reliable communications in channels with geometrical transformations are analyzed within the proposed MAC set-up. Depending on the particular codebook design, we classify these methods into two main groups: template-based codebooks and redundant codebooks. Finally, we perform the analysis of security leaks of each codebook structure in terms of complexity of the worst case attack.
In data-hiding the issue of the achievable rate maximization is closely related to the problem of... more In data-hiding the issue of the achievable rate maximization is closely related to the problem of host interference cancellation. The optimal host interference cancellation relies on the knowledge of the host realization and the channel statistics (the additive white Gaussian noise (AWGN) variance) available at the encoder a priori to the transmission. The latter assumption can be rarely met in practical situations. Contrarily to the Costa set-up where the encoder is optimized for the particular state of the independent and identically distributed (i.i.d.) Gaussian attacking channel, we address the problem of asymmetrically informed data-hiding optimal encoder design assuming that the host interference probability density function (pdf) is an i.i.d. Laplacian and the channel variance lies on some known interval. The presented experimental results advocate the advantages of the developed embedding strategy.
In digital media transfer, geometrical transformations desynchronize the communications between t... more In digital media transfer, geometrical transformations desynchronize the communications between the encoder and the decoder. Therefore, an attempt to decode the message based on the direct output of the channel with random geometrical state fails. The main goal of this paper is to analyze the conditions of reliable communications based on structured codebooks in channels with geometrical transformations. Structured codebooks include codewords that have some features or statistics designed for synchronization purposes. In the design of capacity approaching data-hiding codes, host interference problem should be resolved. The solution to this problem is to perform the message coding based on random binning dependent on host-state. On the other hand, to achieve robustness to geometrical transformations, the codewords should have host independent statistics and encoding should be performed using random coding. To satisfy these conflicting requirements we propose Multiple Access Channel (MAC) framework where the message is split between two encoders designed based on the random binning and random coding principles. The message encoded according to random coding additionally serves for synchronization purposes. Sequentially, all existing methods that are proposed for reliable communications in channels with geometrical transformations are analyzed within the proposed MAC set-up. Depending on the particular codebook design, we classify these methods into two main groups: template-based codebooks and redundant codebooks. Finally, we perform the analysis of security leaks of each codebook structure in terms of complexity of the worst case attack.
Periodical watermark embedding has been especially proposed to cope with geometrical attacks. Usi... more Periodical watermark embedding has been especially proposed to cope with geometrical attacks. Using a diversity approach, this method allows to decrease the probability of error in the case of additive attacks. It is usually admitted that the worst additive attack consists in the addition of additive white Gaussian noise (AWGN). However, our theoretical capacity analysis of periodical watermarking demonstrates that periodical AWGN in the optimal attacking strategy leads to more significant drop of the capacity than AWGN test channel from rate distortion.
In this paper we analyze security of robust data-hiding in channels with geometrical transformati... more In this paper we analyze security of robust data-hiding in channels with geometrical transformations. We categorize possible decoding strategies for channels with geometrical transformations within the information-theoretic framework for geometrically-robust datahiding. Furthermore, considering template-based and redundantbased design of geometrically robust data-hiding systems, we provide the analysis of general attacking strategies and particular attacking scenarios for each group of structured codebooks. Finally, reversibility of data-hiding and effect of security leakages on system performance are investigated.
In this paper we present a feasibility study of printed document forensics based on steganographi... more In this paper we present a feasibility study of printed document forensics based on steganographic anti-counterfeiting markings using portable devices. We propose two system architectures and analyze their pros and contres for mass usage. Furthermore, we perform an analysis of the probability of error that can be attained in the system based on steganographic anti-counterfeiting markings and explicit the conditions to reach reliable performance.
Geometrical transformations bring synchronization problems into the robust digital data-hiding. P... more Geometrical transformations bring synchronization problems into the robust digital data-hiding. Previous works on this subject were concentrated on the robustness to particular geometrical transformations. In this paper, the achievable rates of reliable robust data-hiding in channels with geometrical transformations are investigated from an informationtheoretic point of view for theoretical set-ups, where lengths of data sequences asymptotically approach infinity.
In this paper, we analyze the reversibility of data hiding techniques based on random binning as ... more In this paper, we analyze the reversibility of data hiding techniques based on random binning as a by-product of pure message communications. We demonstrate the capabilities of unauthorized users to perform hidden data removal using solely a signal processing approach based on optimal estimation as well as consider reversibility on the side of authorized users who have knowledge of the key used for the message hiding. In fact, we show that knowledge of the auxiliary random variable, used in the codebook construction of random binning techniques, is sufficient to perform the optimal reversibility procedure. We compare the optimal rate-distortion region results obtained using more involved coding strategies based on hybrid random binning with those utilizing uncoded transmission. This analysis is performed for the generalized Gel'fand-Pinsker formulation, Gaussian Costa setup and particular practical schemes based on structured codebooks. Finally, we consider some related open issues and possible future extensions.
In this paper we consider the problem of document authentication in electronic and printed forms.... more In this paper we consider the problem of document authentication in electronic and printed forms. We formulate this problem from the information-theoretic perspectives and present the joint source-channel coding theorems showing the performance limits in such protocols. We analyze the security of document authentication methods and present the optimal attacking strategies with corresponding complexity estimates that, contrarily to the existing studies, crucially rely on the information leaked by the authentication protocol. Finally, we present the results of experimental validation of the developed concept that justifies the practical efficiency of the elaborated framework.
In this work, we consider the text data-hiding problem as a particular instance of the well-known... more In this work, we consider the text data-hiding problem as a particular instance of the well-known Gel’fand-Pinsker problem [1]. The text, where some message \(m \in \mathcal{M}\) is to be hidden, is represented by x and called cover text. Each component x i , i = 1, 2, ..., N, of x represents one character from this text. Here, we define a character as an element from a given language alphabet (e.g. the latin alphabet {A, B, ..., Z}). To be more precise, we conceive each character x i as a data structure consisting of multiple component fields (features): name, shape, position, orientation, size, color, etc.
In this paper, we analyze a possibility of reversibility of data-hiding techniques based on rando... more In this paper, we analyze a possibility of reversibility of data-hiding techniques based on random binning from multimedia perspectives. We demonstrate the capabilities of unauthorized users to perform hidden data removal using solely a signal processing approach based on optimal estimation as well as consider reversibility on the side of authorized users who have the knowledge of key used for the message hiding.
Reversibility of data-hiding refers to the reconstruction of original host data at the decoder fr... more Reversibility of data-hiding refers to the reconstruction of original host data at the decoder from the stego data. Previous works on the subject are concentrated on the reversibility of data-hiding techniques from multimedia perspectives. However, from the security point of view, that at our knowledge was not exploited in existing studies, reversibility could be used by an attacker to remove the complete trace of watermark data from the stego data in the sense of designing the worst case attack. Thus, the aim of this paper is to analyze the reversibility of data-hiding techniques based on random binning from the security perspectives.
In this paper we analyze performance of practical robust data-hiding in channels with geometrical... more In this paper we analyze performance of practical robust data-hiding in channels with geometrical transformations. By applying information-theoretic argument we show that performance of a system designed based on both random coding and random binning principles is bounded by the same maximal achievable rate for the cases when communication channel includes geometrical transformations or not. Targeting to provide theoretic performance limits of practical robust data-hiding we model it using a multiple access channel (MAC) with side information (SI) available at one of encoders and present the bounds on achievable rates of reliable communications to such a protocol. Finally, considering template-based and redundant-based design of geometrically robust data-hiding systems, we perform security analysis of their performance and present results in terms of number of trial efforts the attacker needs to completely remove hidden information.
In this paper, we consider the problem of pure information transmission and channel state estimat... more In this paper, we consider the problem of pure information transmission and channel state estimation via state dependent channels. We show that the knowledge of auxiliary random variable, used in the codebook construction of random binning techniques, is sufficient to perform the optimal channel state estimation. We compare the obtained results with optimal rate-distortion region obtained using more involved coding strategies based on hybrid random binning and uncoded transmission. This analysis is performed for the generalized Gel'fand-Pinsker formulation and Gaussian Costa setup.
In this paper, we propose a new theoretical framework for the data-hiding problem of digital and ... more In this paper, we propose a new theoretical framework for the data-hiding problem of digital and printed text documents. We explain how this problem can be seen as an instance of the well-known Gel'fand-Pinsker problem. The main idea for this interpretation is to consider a text character as a data structure consisting of multiple quantifiable features such as shape, position, orientation, size, color, etc. We also introduce color quantization, a new semi-fragile text data-hiding method that is fully automatable, has high information embedding rate, and can be applied to both digital and printed text documents. The main idea of this method is to quantize the color or luminance intensity of each character in such a manner that the human visual system is not able to distinguish between the original and quantized characters, but it can be easily performed by a specialized reader machine. We also describe halftone quantization, a related method that applies mainly to printed text documents. Since these methods may not be completely robust to printing and scanning, an outer coding layer is proposed to solve this issue. Finally, we describe a practical implementation of the color quantization method and present experimental results for comparison with other existing methods. * The concept of strong typicality is nicely introduced in the book by Cover and Thomas 8 † Usually, in the context of data-hiding, a secret key K is shared between both encoder and decoder. The secret key K is used for security purposes. For the sake of completeness explicitly shows the secret key K. However, since in this paper we do not perform a security analysis, we will not refer to it.
In this paper, we analyze a possibility of reversibility of datahiding techniques based on random... more In this paper, we analyze a possibility of reversibility of datahiding techniques based on random binning from multimedia perspectives. We demonstrate the capabilities of unauthorized users to perform hidden data removal using solely a signal processing approach based on optimal estimation as well as consider reversibility on the side of authorized users who have the knowledge of key used for the message hiding.
In digital media transfer, geometrical transformations desynchronize the communications between t... more In digital media transfer, geometrical transformations desynchronize the communications between the encoder and the decoder. Therefore, an attempt to decode the message based on the direct output of the channel with random geometrical state fails. The main goal of this paper is to analyze the conditions of reliable communications based on structured codebooks in channels with geometrical transformations. Structured codebooks include codewords that have some features or statistics designed for synchronization purposes. In the design of capacity approaching data-hiding codes, host interference problem should be resolved. The solution to this problem is to perform the message coding based on random binning dependent on host-state. On the other hand, to achieve robustness to geometrical transformations, the codewords should have host independent statistics and encoding should be performed using random coding. To satisfy these conflicting requirements we propose Multiple Access Channel (MAC) framework where the message is split between two encoders designed based on the random binning and random coding principles. The message encoded according to random coding additionally serves for synchronization purposes. Sequentially, all existing methods that are proposed for reliable communications in channels with geometrical transformations are analyzed within the proposed MAC set-up. Depending on the particular codebook design, we classify these methods into two main groups: template-based codebooks and redundant codebooks. Finally, we perform the analysis of security leaks of each codebook structure in terms of complexity of the worst case attack.
In data-hiding the issue of the achievable rate maximization is closely related to the problem of... more In data-hiding the issue of the achievable rate maximization is closely related to the problem of host interference cancellation. The optimal host interference cancellation relies on the knowledge of the host realization and the channel statistics (the additive white Gaussian noise (AWGN) variance) available at the encoder a priori to the transmission. The latter assumption can be rarely met in practical situations. Contrarily to the Costa set-up where the encoder is optimized for the particular state of the independent and identically distributed (i.i.d.) Gaussian attacking channel, we address the problem of asymmetrically informed data-hiding optimal encoder design assuming that the host interference probability density function (pdf) is an i.i.d. Laplacian and the channel variance lies on some known interval. The presented experimental results advocate the advantages of the developed embedding strategy.
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Papers by Emre Topak