Research On Key Technologies Of Secret Sharing Based On Image Carrier

With the development of Internet technology and digital multimedia technology,dig-ital images are becoming more and more popular,but their security are also threatened.In particular,private personal privacy images,commercial confidential images,medical images,and military images involving information of individuals,companies,public util-ities,and the military are easily obtained,tampered with and destroyed during storage and transmission,so its security have also attracted more attention.As a special symbol image,QR code is widely used in mobile commerce,e-commerce,product information transmission and recognition,and user service experience with the development of mobile devices.It is easy to be tampered with and destroyed when it is in the form of a digital version or a printed version,so its security protection issues are becoming more and more important.Image encryption technology and information hiding technology are often used to protect the security of images.Compared with them,secret sharing technology has the characteristics of loss tolerance and permission control in addition to security.This paper focuses on the problem of robustness,meaningful shadow images and weight assignment.Based on the image,the key technologies of secret sharing of QR codes of different image types and grayscale BMP images are studied.The main contents of this thesis are as follows:(1)This theis proposes a secret sharing scheme based on binary QR code with robust and meaningful shadow image,and designs a secret sharing algorithm combining binary QR code and XVSS,which solves the problem of low robustness of existing schemes.The proposed scheme utilizes the defect that the padding codewords are not checked when a QR code is encoded and replaces the padding codewords of the QR code by the bits of shadows shared from the secret image.And in the secret image recovery phase,the en-crypted data of the padding codeword area is corrected and then operated,thereby main-taining the error correction capability of the QR code.The scheme has features such as meaningful shadow image,(k,n)threshold,robustness,and no pixel expansion.The ef-fectiveness of the scheme is described by experiment of robustness test.The comparison with the relative schemes shows that the scheme has better robustness.(2)This thesis proposes a robust visual secret sharing scheme with meaningful shadow images and designs a secret sharing algorithm combining grayscale QR code and XVSS,which improves the recovery quality of secret images.In this scheme,the most signifi-cant bit plane of the grayscale QR code cover images are kept unchanged,and the second significant bit planes are replaced by the initial binary QR code shadow images in which shared the secret QR code,and the other bit planes are randomized to generate grayscale QR code shadow images.In the recovery of secret images,it is robust and can achieve lossless recovery.This scheme has higher quality than other schemes in recovering secret images.It has the characteristics of meaningful shadow images,(n,n)threshold and no pixel expansion.The experimental results demonstrate the characteristics of the scheme.(3)This thesis proposes a secret sharing scheme of grayscale BMP images with dif-ferent weights,designs a secret sharing algorithm based on CRT with different weights,realizes the secret sharing of gray images with different weights,and analyzes the effect of weights on the restoration of secret image quality influences.Compared with polynomial secret sharing,this scheme has lower computational complexity.In addition,this scheme also has a(k,n)threshold feature.When the number of shadow images participating in the restoration is greater than or equal to k,as the weight and number of shadow images increase,the quality of the restored secret image is also improved.When all shadow im-ages are involved in recovery,the secret image can be restored without loss.Relevant theoretical analysis and experimental results verify the effectiveness of the scheme.(4)This thesis proposes two different secret sharing schemes of color QR codes,de-signs two kinds of secret sharing algorithms of color QR codes.Both algorithms realize the secret sharing based on color QR codes.The generated color QR code shadow images are meaningful and robust.In the first scheme,a secret sharing algorithm for continu-ously embedding secret information in different planes of a color QR code is proposed.The threshold of the first scheme is(n,n)(2 ? n ? 3),and the secret image can be recovered by performing OR and XOR operation.In the second scheme,a sharing al-gorithm is proposed in which secret information are dispersedly embedded in different planes of a colored QR code.A single shadow image is generated in the scheme.When the standard decoder decodes,the original color QR code content is obtained,and the se-cret information can be decoded simultaneously using decryption algorithm.The relevant experimental results show the effectiveness of the scheme.