On the tradeoff between security and Robustness of the Trellis Coded Quantization scheme

The steganographic security in the Cachin´s work is defined as the statistical invisibility between the host signal and its marked version. At contrary, the robustness to an attack is not a prime goal. In robust watermarking, this is exactly the inverse. The scalar costa scheme (SCS) is a typical example of this fact. Indeed, this scheme is robust to additive white Gaussian noise (AWGN) attack but is drastically insecure since its probability density function for Gaussian host signal is severely discontinuous. An improved scheme has been proposed by Guillon et al. which increases the security to the detriment of the robustness. In this paper, we propose a new watermarking scheme, based on the combination of the spread transform (ST) and the trellis coded quantization (TCQ) which is secure and robust to AWGN attack.