Research On The Weighted Threshold Secret Image Sharing Scheme

Secret image sharing is an important branch of secret sharing, which is drawing researchers’attention and interest these years, with the development of multi-media and network technology. Secret image sharing can be divided into two phrases, sharing phrase and retrieving phrase. In the sharing phrase, the dealer transforms the secret image into a series of share information according to a certain algorithm, and then, embeds the information into a host image to generate a series of shadow images, which are shared between the participants. In the retrieving phrase, the set of participants that meet the number or some special access structure requirements, can get the information out of the shadow images according to a certain algorithm, and eventually recover the original secret image.In the traditional secret image sharing scheme, the participants have the same status, and shadow images are of approximately equal importance, which cannot satisfy some special requirements in the real world. In the weighted threshold access structure, every participant is associated with a weight, and the larger a participant’s weight is, the higher status he has. The secret image can be recovered losslessly, if, and only if, the sum of all the involved shadow images’weights is no less than the given weight threshold. In this paper, we consider the problem of secret image sharing with this access structure. Firstly, we construct a weighted Mignotte sequence based on Iftene’s weighted threshold secret sharing scheme. Then, according to the constructed sequence, we take the secret image apart into secret segments, and generate the shares that need to be inserted into the cover image. Afterwards, we use the quantization operation to embed the share into a host image to generate shadow images with different weights. In the retrieving procedure, a set of shadow images that satisfy the weighted threshold is utilized to restore the distortion-free secret image.The result of our simulation experiment shows that, our weighted threshold secret image sharing scheme is feasible, and both the visual quality of the shadow images and the embedding capacity of the host images is satisfactory. By using several host images, the feasibility of our scheme is proved, irrespective of the host image. Furthermore, the law of the experiment result, and the choice of parameters are also discussed thoroughly in this paper.