Security and Robustness Enhancement for Image Data Hiding

In many applications, data hiding can be viewed as a tradeoff between capacity, robustness (against attacks), and embedding induced distortion. In this paper, we consider a fourth parameter: the security of the hidden information. Specifically, we propose a hash-based randomized embedding algorithm (HRE) that increases the security of the hidden data. We then optimize this algorithm against JPEG attacks. We derive a mathematical expression for the security of our algorithm, using which we show that the security of our algorithm can be increased independent of capacity, robustness, and embedding induced distortion. The maximum security depends only on the length of the key sequence, which is limited only by the size of the host image. Using a joint security and capacity measure, we show that the proposed scheme performs better than current secure quantization based data hiding schemes. We also derive the optimal value of distortion compensation factor of the HRE algorithm against JPEG compression attack. Experimental results show that the operating points achieved by the proposed scheme are 7 dB better than current blind data hiding schemes against the JPEG attack