Research On Security Mechanism And Application Of Secret Image Sharing

With the rapid development of computer technology,enormous important information in digital form is stored in the cloud or database of service providers.The technological revolution brings convenience,while also creates privacy securily risks.Secret sharing provides an idea for solving privacy security,which was proposed by Shamir and Blaklcy.The scheme contains two phases and two types of entities,the secret sharing phase and the secret recovery phase,managers and sub-share holders.It requires the cooperation of no less than k sub-share holders to recover the secret,but less than k holders cannot recover the secret.However,the secret sharing scheme has the disadvantages of illegal participants stealing legal shares,internal holders tampering with saved shares and image reconstruction with large granularity and a single way of reconstruction.Now,there have been a lot of studies on the above problems,but the existing studies still have the following problems:1.The identification accuracy of illegal participants is low,the share verification method is inflexible;2.The share validity detection method is complicated;3.The efficiency of secret image reconstruction is low and the method is single.Based on the above problems,the main work of this paper includes:Aiming at the attack model,share tampering and image application of secret sharing scheme,this paper studies the following three problems:Firstly,aiming at the problems of low identification accuracy of illegal participants and inflexible share verification ways,this paper proposes a verifiable secret sharing scheme based on random grids.Two verification methods are designed in the scheme.The first is that when a third party exists,can verifies the shares presented by all participants according to the private share.The second is that when there is no third party,each participant votes on the shares received,and determine illegal participants according to voting results.Experiments show that the scheme can accurately screen out illegal participants and ensure that secret information is not leaked.Secondly,aiming at the complicated problem of detecting tampered shares,this paper proposes a secret sharing scheme for share anti-spoofing detection with multi-modal recovery.The original scheme is using the hash value for comparison detection.In this scheme,all shares will be converted into bit data in the encryption stage,and data will be deal with the public password,next,the final result will be sent to the detection party.The detection party detects the shares presented by the participants through the XOR operation,and determines whether shares have been tampered,according to whether the public password can be correctly recovered.Experiments show that scheme has the advantages of accuracy of share detection results and simple detection method.Thirdly,Aiming at the low efficiency and single way of secret image reconstruction,this paper proposes a lightweight progressive secret image sharing scheme.In scheme,the scrambled sorting and classification of image blocks rely on the spiral matrix and modulo operation respectively,and finally form a new subgraph.subgraph is encrypted with different thresholds,the additional shadows are stored in a third party.During image reconstruction step,it can be selectively restored according to the required area of the image,to reduce unnecessary calculations and speeding up the reconstruction of target image information.In addition,by modifying the share distribution method,two reconstruction modes can be provided:an all-or-nothing reconstruction mode and a global incremental reconstruction mode.Experiments show that scheme has the advantages of high image reconstruction efficiency and various reconstruction methods.