关键词: 马尔可夫链蒙特卡罗采样, 量化, 盲水印算法, 安全性, 鲁棒性

Abstract: In order to improve the security of watermarking algorithm, a robust blind watermarking based on two forms of key was proposed. Firstly, the watermark was encrypted by a key, then matrix Q was consisted of the first singular value of each block carrier and block Discrete Wavelete Transform (DWT) again to acquire four subbands, the k-th watermark bit was chosen to be embedded in the k-th block's low-frequency, horizontal, vertical and high-frequency subbands of matrix Q by Markov Chain Monte Carlo (MCMC) sampling of four subbands and record the current key of embedded subband. It not only made watermark bit randomization, but also improved the safety of the watermark algorithm. The experimental results show that the proposed watermarking has strong robustness against conventional attacks under the condition of satisfying invisibility, meanwhile, it enhances the security of the watermark algorithm, which is embedded with a different key by MCMC sampling in the watermark embedding process.

Key words: Markov Chain Monte Carlo (MCMC) sampling, quantization, blind watermarking, safety, robustness