Information Security and Cryptography Advanced Statistical Steganalysis Bearbeitet von Rainer Böhme 1. Auflage 2010. Buch. xvi, 288 S. Hardcover ISBN 978 3 642 14312 0 Format (B x L): 15,5 x 23,5 cm Gewicht: 619 g Weitere Fachgebiete > EDV, Informatik > Hardwaretechnische Grundlagen > Kryptographie, Datenverschlüsselung Zu Leseprobe schnell und portofrei erhältlich bei Die Online-Fachbuchhandlung beck-shop.de ist spezialisiert auf Fachbücher, insbesondere Recht, Steuern und Wirtschaft. Im Sortiment finden Sie alle Medien (Bücher, Zeitschriften, CDs, ebooks, etc.) aller Verlage. Ergänzt wird das Programm durch Services wie Neuerscheinungsdienst oder Zusammenstellungen von Büchern zu Sonderpreisen. Der Shop führt mehr als 8 Millionen Produkte.
Contents 1 Introduction... 1 1.1 Steganography and Steganalysis as Empirical Sciences... 1 1.2 Objective and Approach... 2 1.3 Outline... 4 Part I Background and Advances in Theory 2 Principles of Modern Steganography and Steganalysis... 11 2.1 Digital Steganography and Steganalysis... 11 2.1.1 Steganographic System... 12 2.1.2 Steganalysis... 13 2.1.3 Relevance in Social and Academic Contexts... 13 2.2 Conventions... 14 2.3 Design Goals and Metrics... 17 2.3.1 Capacity... 17 2.3.2 Steganographic Security... 18 2.3.3 Robustness... 21 2.3.4 Further Metrics... 22 2.4 Paradigms for the Design of Steganographic Systems... 22 2.4.1 Paradigm I: Modify with Caution... 22 2.4.2 Paradigm II: Cover Generation... 23 2.4.3 Dominant Paradigm... 25 2.5 Adversary Models... 26 2.5.1 Passive Warden... 26 2.5.2 Active Warden... 28 2.6 Embedding Domains... 30 2.6.1 Artificial Channels... 30 2.6.2 Spatial and Time Domains... 31 2.6.3 Transformed Domain... 31 2.6.4 Selected Cover Formats: JPEG and MP3... 35 2.6.5 Exotic Covers... 38 xi
xii Contents 2.7 Embedding Operations... 39 2.7.1 LSB Replacement... 40 2.7.2 LSB Matching (±1)... 41 2.7.3 Mod-k Replacement, Mod-k Matching, and Generalisations... 45 2.7.4 Multi-Sample Rules... 47 2.7.5 Adaptive Embedding... 48 2.8 Protocols and Message Coding... 49 2.8.1 Public-Key Steganography... 50 2.8.2 Maximising Embedding Efficiency... 53 2.9 Specific Detection Techniques... 57 2.9.1 Calibration of JPEG Histograms... 57 2.9.2 Universal Detectors... 60 2.9.3 Quantitative Steganalysis... 63 2.10 Selected Estimators for LSB Replacement in Spatial Domain Images... 64 2.10.1 RS Analysis... 64 2.10.2 Sample Pair Analysis... 67 2.10.3 Higher-Order Structural Steganalysis... 69 2.10.4 Weighted Stego Image Steganalysis... 73 2.11 Summary and Further Steps... 76 3 Towards a Theory of Cover Models... 79 3.1 Steganalyst s Problem Formalised... 79 3.1.1 The Plausibility Heuristic... 79 3.1.2 Application to Digital Steganography... 81 3.1.3 Incognisability of the Cover Distribution... 83 3.2 Cover Models... 84 3.2.1 Defining Cover Models... 84 3.2.2 Options for Formulating Cover Models... 86 3.2.3 Cover Models and Detection Performance... 88 3.2.4 Summary and Motivations for Studying Cover Models 92 3.3 Dealing with Heterogeneous Cover Sources... 93 3.3.1 Mixture Distributions... 95 3.3.2 The Mixture Cover Model... 95 3.4 Relation to Prior Information-Theoretic Work... 97 3.4.1 Theoretical Limits... 98 3.4.2 Observability Bounds... 99 3.4.3 Computational Bounds... 101 3.4.4 Applicability of the Theory of Cover Models... 102 3.4.5 Indeterminacy in the Cover... 104 3.5 Instances of Cover Models for Heterogeneous Sources... 106 3.6 Summary... 107
Contents xiii Part II Specific Advances in Steganalysis 4 Detection of Model-Based Steganography with First-Order Statistics... 111 4.1 Fundamentals of Model-Based Steganography... 111 4.2 MB1: An Embedding Function for JPEG Covers... 114 4.3 Detection Method... 117 4.4 Experimental Validation... 120 4.5 Summary and Outlook... 123 4.5.1 Limitations and Future Directions... 124 4.5.2 Possible (Short-Term) Countermeasures... 125 4.5.3 Implications for More Secure Steganography... 126 5 Models of Heterogeneous Covers for Quantitative Steganalysis... 127 5.1 Metrics for Quantitative Steganalysis... 128 5.1.1 Conventional Metrics... 128 5.1.2 Improved Metrics Based on a Distribution Model... 130 5.1.3 Decomposition of Estimation Errors... 135 5.2 Measurement of Sensitivity to Cover Properties... 141 5.2.1 Method... 142 5.2.2 Modelling the Shape of the Between-Image Distribution144 5.2.3 Modelling the Shape of the Within-Image Distribution 148 5.3 Summary and Conclusion... 151 6 Improved Weighted Stego Image Steganalysis... 155 6.1 Enhanced WS for Never-Compressed Covers... 155 6.1.1 Enhanced Predictor... 156 6.1.2 Enhanced Calculation of Weights... 161 6.1.3 Enhanced Bias Correction... 166 6.1.4 Experimental Results... 166 6.2 Adaptation of WS to JPEG Pre-Compressed Covers... 172 6.2.1 Improved Predictor... 173 6.2.2 Estimation of the Cover s JPEG Compression Quality 176 6.2.3 Experimental Results... 177 6.3 Summary and Outlook... 182 7 Using Encoder Artefacts for Steganalysis of Compressed Audio Streams... 183 7.1 MP3 Steganography and Steganalysis... 183 7.1.1 Problem Statement in the Mixture Cover Model Framework... 185 7.1.2 Level of Analysis and Related Work... 185 7.1.3 Method... 187
xiv Contents 7.2 Description of Features... 189 7.2.1 Features Based on the Compression Size Control Mechanism... 190 7.2.2 Features Based on Model Decisions... 192 7.2.3 Features Based on Capability Usage... 194 7.2.4 Feature Based on Stream Formatting... 195 7.3 Experimental Results for Encoder Detection... 196 7.3.1 Single-Compressed Audio Files... 196 7.3.2 Importance of Individual Features... 199 7.3.3 Influence of Double-Compression... 199 7.4 Experimental Results for Improved Steganalysis... 201 7.5 Explorative Analysis of Encoder Similarities... 202 7.6 Summary and Discussion... 204 7.6.1 Limitations and Future Directions... 204 7.6.2 Transferability to Other Formats... 205 7.6.3 Related Applications... 206 Part III Synthesis 8 General Discussion... 209 8.1 Summary of Results... 209 8.1.1 Results Based on Informal Arguments... 209 8.1.2 Results Based on Mathematical Proofs... 210 8.1.3 Results Based on Empirical Evidence... 211 8.2 Limitations... 212 8.3 Directions for Future Research... 213 8.3.1 Theoretical Challenges... 214 8.3.2 Empirical Challenges... 214 8.3.3 Practical Challenges... 215 8.4 Conclusion and Outlook... 215 A Description of Covers Used in the Experiments... 219 B Spurious Steganalysis Results Using the van Hateren Image Database... 223 C Proof of Weighted Stego Image (WS) Estimator... 227 D Derivation of Linear Predictor for Enhanced WS... 229 E Game for Formal Security Analysis... 231 F Derivation of ROC Curves and AUC Metric for Example Cover Models... 233 G Supplementary Figures and Tables... 235
Contents xv References... 245 List of Tables... 263 List of Figures... 266 List of Acronyms... 269 List of Symbols... 272 List of Functions... 278 Index... 280