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How quantization based schemes can be used in image steganographic context / Braci, Sofiane in Signal processing. Image communication, Vol. 26 N° 8-9 (Octobre 2011) 

Public ISBD [article]  in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 567–576 Titre : How quantization based schemes can be used in image steganographic context Type de document : texte imprimé Auteurs : Braci, Sofiane, Auteur ; Claude Delpha, Auteur ; Rémy Boyer, Auteur Année de publication : 2012 Article en page(s) : pp. 567–576 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Image  processing  for  watermarking  and  steganography  Costa  scheme  Spread  transform Résumé : The quantization based embedding systems are widely used in the information hiding applications, thanks to their efficiency and simplicity. Moreover, they are known to be insecure in steganography context according to the Cachins' security definition because they distort the stego-signal probability density function. In this paper, we show that using the well-known spread transform (ST) combining with quantization based embedding systems provides an ε-secure stego-system in the sense of Cachin's security definition. In other words, we show theoretically that this system preserves, in the sense of the relative entropy, the probability density function of the stego-signal as long as the ratio between the quantization step and the square root of the spreading factor is small. This highlights the fundamental tradeoff between these two quantities. Our theoretical conclusions are validated and illustrated on real images. Finally, a comparison with the Solanki et al. blind steganographic scheme is given. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000907 [article] How quantization based schemes can be used in image steganographic context [texte imprimé] / Braci, Sofiane, Auteur ; Claude Delpha, Auteur ; Rémy Boyer, Auteur . - 2012 . - pp. 567–576. Electronique Langues : Anglais (eng) in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 567–576 Mots-clés : Image  processing  for  watermarking  and  steganography  Costa  scheme  Spread  transform Résumé : The quantization based embedding systems are widely used in the information hiding applications, thanks to their efficiency and simplicity. Moreover, they are known to be insecure in steganography context according to the Cachins' security definition because they distort the stego-signal probability density function. In this paper, we show that using the well-known spread transform (ST) combining with quantization based embedding systems provides an ε-secure stego-system in the sense of Cachin's security definition. In other words, we show theoretically that this system preserves, in the sense of the relative entropy, the probability density function of the stego-signal as long as the ratio between the quantization step and the square root of the spreading factor is small. This highlights the fundamental tradeoff between these two quantities. Our theoretical conclusions are validated and illustrated on real images. Finally, a comparison with the Solanki et al. blind steganographic scheme is given. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000907