Pub Date : 2012-12-01DOI: 10.1109/WIFS.2012.6412646
Xiao-Ming Chen, Michael Arnold, P. Baum, G. Doërr
AC-3 audio compression find applications in home cinema, DVD, BD and digital television. This paper addresses the challenge of transparently watermarking AC-3 bit streams instead of the conventional decoding - baseband watermarking - re-encoding approach. We discuss the alternate possibilities to embed watermarks by altering the MDCT coefficients delivered in the bit stream, which consists of mantissas and exponents. We then introduce an AC-3 bit stream watermarking system that is accomplished by solely modifying mantissas to obtain a low computational complexity. We subsequently present the associated watermark detector, which proves to be interoperable with a legacy watermarking system that operates in a different embedding domain. Finally, we compare the proposed bit stream system with the regular decoding - watermarking - re-encoding chain to verify the quality and robustness.
{"title":"AC-3 bit stream watermarking","authors":"Xiao-Ming Chen, Michael Arnold, P. Baum, G. Doërr","doi":"10.1109/WIFS.2012.6412646","DOIUrl":"https://doi.org/10.1109/WIFS.2012.6412646","url":null,"abstract":"AC-3 audio compression find applications in home cinema, DVD, BD and digital television. This paper addresses the challenge of transparently watermarking AC-3 bit streams instead of the conventional decoding - baseband watermarking - re-encoding approach. We discuss the alternate possibilities to embed watermarks by altering the MDCT coefficients delivered in the bit stream, which consists of mantissas and exponents. We then introduce an AC-3 bit stream watermarking system that is accomplished by solely modifying mantissas to obtain a low computational complexity. We subsequently present the associated watermark detector, which proves to be interoperable with a legacy watermarking system that operates in a different embedding domain. Finally, we compare the proposed bit stream system with the regular decoding - watermarking - re-encoding chain to verify the quality and robustness.","PeriodicalId":396789,"journal":{"name":"2012 IEEE International Workshop on Information Forensics and Security (WIFS)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115636563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/WIFS.2012.6412657
H. Fradi, J. Dugelay
People counting is a crucial component in visual surveillance mainly for crowd monitoring and management. Recently, significant progress has been made in this field by using features regression. In this context, perspective distortions have been frequently studied, however, crowded scenes remain particularly challenging and could deeply affect the count because of the partial occlusions that occur between individuals. To address these challenges, we propose a people counting approach that harness the advantage of incorporating an uniform motion model into Gaussian Mixture Model (GMM) background subtraction to obtain high accurate foreground segmentation. The counting is based on foreground measurements, where a perspective normalization and a crowd measure-informed corner density are introduced with foreground pixel counts into a single feature. Afterwards, the correspondence between this frame-wise feature and the number of persons is learned by Gaussian Process regression. Experimental results demonstrate the benefits of integrating GMM with motion cue, and normalizing the proposed feature as well. Also, by means of comparisons to other feature-based methods, our approach has been experimentally validated showing more accurate results.
{"title":"Low level crowd analysis using frame-wise normalized feature for people counting","authors":"H. Fradi, J. Dugelay","doi":"10.1109/WIFS.2012.6412657","DOIUrl":"https://doi.org/10.1109/WIFS.2012.6412657","url":null,"abstract":"People counting is a crucial component in visual surveillance mainly for crowd monitoring and management. Recently, significant progress has been made in this field by using features regression. In this context, perspective distortions have been frequently studied, however, crowded scenes remain particularly challenging and could deeply affect the count because of the partial occlusions that occur between individuals. To address these challenges, we propose a people counting approach that harness the advantage of incorporating an uniform motion model into Gaussian Mixture Model (GMM) background subtraction to obtain high accurate foreground segmentation. The counting is based on foreground measurements, where a perspective normalization and a crowd measure-informed corner density are introduced with foreground pixel counts into a single feature. Afterwards, the correspondence between this frame-wise feature and the number of persons is learned by Gaussian Process regression. Experimental results demonstrate the benefits of integrating GMM with motion cue, and normalizing the proposed feature as well. Also, by means of comparisons to other feature-based methods, our approach has been experimentally validated showing more accurate results.","PeriodicalId":396789,"journal":{"name":"2012 IEEE International Workshop on Information Forensics and Security (WIFS)","volume":"285 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126855167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/WIFS.2012.6412626
Bing-Rong Lin, Ye Wang, S. Rane
Alice and Bob are mutually untrusting curators who possess separate databases containing information about a set of respondents. This data is to be sanitized and published to enable accurate statistical analysis, while retaining the privacy of the individual respondents in the databases. Further, an adversary who looks at the published data must not even be able to compute statistical measures on it. Only an authorized researcher should be able to compute marginal and joint statistics. This work is an attempt toward providing a theoretical formulation of privacy and utility for problems of this type. Privacy of the individual respondents is formulated using ϵ-differential privacy. Privacy of the marginal and joint statistics on the distributed databases is formulated using a new model called δ-distributional ϵ-differential privacy. Finally, a constructive scheme based on randomized response is presented as an example mechanism that satisfies the formulated privacy requirements.
{"title":"A framework for privacy preserving statistical analysis on distributed databases","authors":"Bing-Rong Lin, Ye Wang, S. Rane","doi":"10.1109/WIFS.2012.6412626","DOIUrl":"https://doi.org/10.1109/WIFS.2012.6412626","url":null,"abstract":"Alice and Bob are mutually untrusting curators who possess separate databases containing information about a set of respondents. This data is to be sanitized and published to enable accurate statistical analysis, while retaining the privacy of the individual respondents in the databases. Further, an adversary who looks at the published data must not even be able to compute statistical measures on it. Only an authorized researcher should be able to compute marginal and joint statistics. This work is an attempt toward providing a theoretical formulation of privacy and utility for problems of this type. Privacy of the individual respondents is formulated using ϵ-differential privacy. Privacy of the marginal and joint statistics on the distributed databases is formulated using a new model called δ-distributional ϵ-differential privacy. Finally, a constructive scheme based on randomized response is presented as an example mechanism that satisfies the formulated privacy requirements.","PeriodicalId":396789,"journal":{"name":"2012 IEEE International Workshop on Information Forensics and Security (WIFS)","volume":"407 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124324578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/WIFS.2012.6412645
S. Voloshynovskiy, F. Farhadzadeh, O. Koval, T. Holotyak
Content fingerprinting and digital watermarking are techniques that are used for the content protection and distribution monitoring. Nowadays, both techniques are well studied and their shortcomings are understood. In this paper, we introduce a new framework named as active content fingerprinting that takes the best from two worlds of content fingerprinting and digital watermarking to overcome some of fundamental restrictions of these techniques in terms of performance and complexity. The proposed framework extends the encoding of conventional content fingerprinting in the way similar to digital watermarking thus allowing to extract the fingerprints from the modified cover data. We consider several encoding strategies, examine the performance of the proposed schemes in terms of bit error rate and compare it with those of conventional fingerprinting and digital watermarking.
{"title":"Active content fingerprinting: A marriage of digital watermarking and content fingerprinting","authors":"S. Voloshynovskiy, F. Farhadzadeh, O. Koval, T. Holotyak","doi":"10.1109/WIFS.2012.6412645","DOIUrl":"https://doi.org/10.1109/WIFS.2012.6412645","url":null,"abstract":"Content fingerprinting and digital watermarking are techniques that are used for the content protection and distribution monitoring. Nowadays, both techniques are well studied and their shortcomings are understood. In this paper, we introduce a new framework named as active content fingerprinting that takes the best from two worlds of content fingerprinting and digital watermarking to overcome some of fundamental restrictions of these techniques in terms of performance and complexity. The proposed framework extends the encoding of conventional content fingerprinting in the way similar to digital watermarking thus allowing to extract the fingerprints from the modified cover data. We consider several encoding strategies, examine the performance of the proposed schemes in terms of bit error rate and compare it with those of conventional fingerprinting and digital watermarking.","PeriodicalId":396789,"journal":{"name":"2012 IEEE International Workshop on Information Forensics and Security (WIFS)","volume":"34 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116268613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/WIFS.2012.6412641
David Vázquez-Padín, M. Fontani, T. Bianchi, Pedro Comesaña Alfaro, A. Piva, M. Barni
Video forensics is an emerging discipline, that aims at inferring information about the processing history undergone by a digital video in a blind fashion. In this work we introduce a new forensic footprint and, based on it, propose a method for detecting whether a video has been encoded twice; if this is the case, we also estimate the size of the Group Of Pictures (GOP) employed during the first encoding. As shown in the experiments, the footprint proves to be very robust even in realistic settings (i.e., when encoding is carried out using typical compression rates), that are rarely addressed by existing techniques.
{"title":"Detection of video double encoding with GOP size estimation","authors":"David Vázquez-Padín, M. Fontani, T. Bianchi, Pedro Comesaña Alfaro, A. Piva, M. Barni","doi":"10.1109/WIFS.2012.6412641","DOIUrl":"https://doi.org/10.1109/WIFS.2012.6412641","url":null,"abstract":"Video forensics is an emerging discipline, that aims at inferring information about the processing history undergone by a digital video in a blind fashion. In this work we introduce a new forensic footprint and, based on it, propose a method for detecting whether a video has been encoded twice; if this is the case, we also estimate the size of the Group Of Pictures (GOP) employed during the first encoding. As shown in the experiments, the footprint proves to be very robust even in realistic settings (i.e., when encoding is carried out using typical compression rates), that are rarely addressed by existing techniques.","PeriodicalId":396789,"journal":{"name":"2012 IEEE International Workshop on Information Forensics and Security (WIFS)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123538698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/WIFS.2012.6412631
Samuel Marchal, J. François, R. State, T. Engel
In network level forensics, Domain Name Service (DNS) is a rich source of information. This paper describes a new approach to mine DNS data for forensic purposes. We propose a new technique that leverages semantic and natural language processing tools in order to analyze large volumes of DNS data. The main research novelty consists in detecting malicious and dangerous domain names by evaluating the semantic similarity with already known names. This process can provide valuable information for reconstructing network and user activities. We show the efficiency of the method on experimental real datasets gathered from a national passive DNS system.
{"title":"Semantic based DNS forensics","authors":"Samuel Marchal, J. François, R. State, T. Engel","doi":"10.1109/WIFS.2012.6412631","DOIUrl":"https://doi.org/10.1109/WIFS.2012.6412631","url":null,"abstract":"In network level forensics, Domain Name Service (DNS) is a rich source of information. This paper describes a new approach to mine DNS data for forensic purposes. We propose a new technique that leverages semantic and natural language processing tools in order to analyze large volumes of DNS data. The main research novelty consists in detecting malicious and dangerous domain names by evaluating the semantic similarity with already known names. This process can provide valuable information for reconstructing network and user activities. We show the efficiency of the method on experimental real datasets gathered from a national passive DNS system.","PeriodicalId":396789,"journal":{"name":"2012 IEEE International Workshop on Information Forensics and Security (WIFS)","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125974804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/WIFS.2012.6412649
M. Barni, B. Tondi
In the attempt to provide a mathematical background to multimedia forensics, we introduce the source identification game with training data. The game models a scenario in which a forensic analyst has to decide whether a test sequence has been drawn from a source X or not. In turn, the adversary takes a sequence generated by a different source a modifies it in such a way to induce a classification error. The source X is known only through one or more training sequences. We derive the asymptotic Nash equilibrium of the game under the assumption that the analyst relies only on first order statistics of the test sequence. A geometric interpretation of the result is given together with a comparison with a similar version of the game with known sources. The comparison between the two versions of the games gives interesting insights into the differences and similarities of the two games.
{"title":"Optimum forensic and counter-forensic strategies for source identification with training data","authors":"M. Barni, B. Tondi","doi":"10.1109/WIFS.2012.6412649","DOIUrl":"https://doi.org/10.1109/WIFS.2012.6412649","url":null,"abstract":"In the attempt to provide a mathematical background to multimedia forensics, we introduce the source identification game with training data. The game models a scenario in which a forensic analyst has to decide whether a test sequence has been drawn from a source X or not. In turn, the adversary takes a sequence generated by a different source a modifies it in such a way to induce a classification error. The source X is known only through one or more training sequences. We derive the asymptotic Nash equilibrium of the game under the assumption that the analyst relies only on first order statistics of the test sequence. A geometric interpretation of the result is given together with a comparison with a similar version of the game with known sources. The comparison between the two versions of the games gives interesting insights into the differences and similarities of the two games.","PeriodicalId":396789,"journal":{"name":"2012 IEEE International Workshop on Information Forensics and Security (WIFS)","volume":"35 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116752161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/WIFS.2012.6412653
I. Caciula, D. Coltuc
The distortion introduced by the watermarking depends on the embedded capacity. For the difference expansion reversible watermarking, the classical threshold control does not ensure a fine tuning of the embedding capacity and the simple partial embedding can introduce artifacts. This paper proposes the fine tuning of the capacity by splitting the image into two parts and by marking them with consecutive threshold values. Intermediate capacity values between the ones provided by the thresholds are obtained by varying the ratio between the two parts. The method ensures a fine control of the capacity without introducing artifacts. Experimental results are provided.
{"title":"Capacity control of reversible watermarking by two-thresholds embedding","authors":"I. Caciula, D. Coltuc","doi":"10.1109/WIFS.2012.6412653","DOIUrl":"https://doi.org/10.1109/WIFS.2012.6412653","url":null,"abstract":"The distortion introduced by the watermarking depends on the embedded capacity. For the difference expansion reversible watermarking, the classical threshold control does not ensure a fine tuning of the embedding capacity and the simple partial embedding can introduce artifacts. This paper proposes the fine tuning of the capacity by splitting the image into two parts and by marking them with consecutive threshold values. Intermediate capacity values between the ones provided by the thresholds are obtained by varying the ratio between the two parts. The method ensures a fine control of the capacity without introducing artifacts. Experimental results are provided.","PeriodicalId":396789,"journal":{"name":"2012 IEEE International Workshop on Information Forensics and Security (WIFS)","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117350653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/WIFS.2012.6412652
Sergio Bravo-Solorio, Chang-Tsun Li, A. Nandi
This paper proposes a new fragile watermarking capable of perfectly restoring the original watermarked pixels of a tampered image. First, a secure block-wise mechanism, resilient to cropping, is used to localise tampered blocks of pixels. The authentic pixels and some reference bits are then used to estimate the original 5 most significant bits (MSBs) of the tampered pixels by means of an exhaustive and iterative restoration mechanism. Results are presented to demonstrate the restoration capabilities of the proposed mechanism.
{"title":"Watermarking method with exact self-propagating restoration capabilities","authors":"Sergio Bravo-Solorio, Chang-Tsun Li, A. Nandi","doi":"10.1109/WIFS.2012.6412652","DOIUrl":"https://doi.org/10.1109/WIFS.2012.6412652","url":null,"abstract":"This paper proposes a new fragile watermarking capable of perfectly restoring the original watermarked pixels of a tampered image. First, a secure block-wise mechanism, resilient to cropping, is used to localise tampered blocks of pixels. The authentic pixels and some reference bits are then used to estimate the original 5 most significant bits (MSBs) of the tampered pixels by means of an exhaustive and iterative restoration mechanism. Results are presented to demonstrate the restoration capabilities of the proposed mechanism.","PeriodicalId":396789,"journal":{"name":"2012 IEEE International Workshop on Information Forensics and Security (WIFS)","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131671237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/WIFS.2012.6412632
J. Elices, F. Pérez-González
We present an attack to locate hidden servers in anonymous common networks. The attack is based on correlating the flow of messages that arrives to a certain server with the flow that is created by the attacker client. The fingerprint is constructed by sending requests, each request determines one interval. To improve the performance a prediction of the time of arrival is done for each request. We propose an optimal detector to decide whether the flow is fingerprinted, based on the Neyman-Pearson lemma. The usefulness of our algorithm is shown for the case of locating a Tor Hidden Service (HS), where we analytically determine the parameters that yield a fixed false positive probability and compute the corresponding detection probability. Finally, we empirically validate our results with a simulator and with a real implementation on the live Tor network. Results show that our algorithm outperforms any other flow watermarking scheme. Our design also yields a small detectability.
{"title":"Fingerprinting a flow of messages to an anonymous server","authors":"J. Elices, F. Pérez-González","doi":"10.1109/WIFS.2012.6412632","DOIUrl":"https://doi.org/10.1109/WIFS.2012.6412632","url":null,"abstract":"We present an attack to locate hidden servers in anonymous common networks. The attack is based on correlating the flow of messages that arrives to a certain server with the flow that is created by the attacker client. The fingerprint is constructed by sending requests, each request determines one interval. To improve the performance a prediction of the time of arrival is done for each request. We propose an optimal detector to decide whether the flow is fingerprinted, based on the Neyman-Pearson lemma. The usefulness of our algorithm is shown for the case of locating a Tor Hidden Service (HS), where we analytically determine the parameters that yield a fixed false positive probability and compute the corresponding detection probability. Finally, we empirically validate our results with a simulator and with a real implementation on the live Tor network. Results show that our algorithm outperforms any other flow watermarking scheme. Our design also yields a small detectability.","PeriodicalId":396789,"journal":{"name":"2012 IEEE International Workshop on Information Forensics and Security (WIFS)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131936435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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