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Title: Revisiting Perturbed Quantization
In this work, we revisit Perturbed Quantization steganography with modern tools available to the steganographer today, including near-optimal ternary coding and content-adaptive embedding with side-information. In PQ, side-information in the form of rounding errors is manufactured by recompressing a JPEG image with a ju- diciously selected quality factor. This side-information, however, cannotbeusedinthesamefashionasinconventionalside-informed schemes nowadays as this leads to highly detectable embedding. As a remedy, we utilize the steganographic Fisher information to allocate the payload among DCT modes. In particular, we show that the embedding should not be constrained to contributing coef- ficients only as in the original PQ but should be expanded to the so-called “contributing DCT modes.” This approach is extended to color images by slightly modifying the SI-UNIWARD algorithm. Using the best detectors currently available, it is shown that by manufacturing side information with double compression, one can embedthesameamountofinformationintothedoubly-compressed cover image with a significantly better security than applying J- UNIWARD directly in the single-compressed image. At the end of the paper, we show that double compression with the same qual- ity makes side-informed steganography extremely detectable and should be avoided.  more » « less
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ACM Information Hiding and Multimedia Security Workshop
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National Science Foundation
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