Security of spread-spectrum-based data hiding
Luis Pérez-Freire, Pierre Moulin, Fernando Pérez‐González · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2007
This paper presents an information-theoretic analysis of security for data hiding methods based on spread spectrum. The security is quantified by means of the mutual information between the observed watermarked signals and the secret carrier (a.k.a. spreading vector) that conveys the watermark, a measure that can be used to bound the number of observations needed to estimate the carrier up to a certain accuracy. The main results of this paper permit to establish fundamental security limits for this kind of methods and to draw conclusions about the tradeoffs between robustness and security. Specifically, the impact of the dimensionality of the embedding function, the host rejection, and the embedding distortion in the security level is investigated, and in some cases explicitly quantified.