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Proceedings Paper

A curiosity regarding steganographic capacity of pathologically nonstationary sources
Author(s): Andrew D. Ker
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Paper Abstract

Square root laws state that the capacity of an imperfect stegosystem - where the embedding does not preserve the cover distribution exactly - grows with the square root of cover size. Such laws have been demonstrated empirically and proved mathematically for a variety of situations, but not for nonstationary covers. Our aim here is to examine a highly simplified nonstationary source, which can have pathological and unpredictable behaviour. Intuition suggests that, when the cover source distribution is not perfectly known in advance, it should be impossible to distinguish covers and stego objects because the detector can never learn enough information about the varying cover source. However we show a strange phenomenon, whereby it is possible to distinguish stego and cover objects as long as the cover source is stationary for two pixels at a time, and then the capacity follows neither a square root law nor a linear law.

Paper Details

Date Published: 10 February 2011
PDF: 12 pages
Proc. SPIE 7880, Media Watermarking, Security, and Forensics III, 78800E (10 February 2011); doi: 10.1117/12.871885
Show Author Affiliations
Andrew D. Ker, Univ. of Oxford (United Kingdom)

Published in SPIE Proceedings Vol. 7880:
Media Watermarking, Security, and Forensics III
Nasir D. Memon; Jana Dittmann; Adnan M. Alattar; Edward J. Delp III, Editor(s)

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