Natural Watermarking: a secure spread spectrum technique for WOA
Résumé
This paper presents a spread spectrum (SS) watermarking technique that is secure against carriers estimation in a Watermark Only Attack framework. After reviewing the sufficient conditions to design se- cure algorithms for watermarking and steganography, we present a setup based on Blind Source Separation (BSS) theory to assess the lack of security of classical SS techniques such as classical SS or ISS. We mo- tivate a new SS watermarking algorithm called Natural Watermarking (NW) where the estimation of the secret carriers is impossible and which achieves perfect secrecy thanks to unchanged Gaussian distributions of the secret carriers. The theoretical evaluation of the NW security is carried out and the case of multi-bit embedding is addressed. Finally, a robust extension of NW is presented and the properties of NW and Robust-NW are both practically verified.