In this paper, an efficient chaos-based image encryption scheme is proposed, which uses the imitating jigsaw method containing revolving and shifting operations. scheme, there are three processes in encryption: preprocessing, process, postprocessing. original partitioned into 64 × pixel blocks then randomly revolved shifted under control sequences generated by hyperchaotic Lorenz system whose i...

one of the most important parameters in evaluating a watermarking algorithm is its capacity. generally, watermarking capacity is expressed by bits per pixel (bpp) unit measure. but this measure does not show what the side effects would be on image quality, watermark robustness and capacity. in this paper we propose a three dimensional measure named capacity surface which shows the effects of ca...