Research On Verifiable Encrypted Image Retrieval Based On Blockchain

With the widespread popularization and use of mobile camera equipment,image data shows an explosive trend of increasing.Users often outsource large amounts of image data to cloud servers to reduce on-premises storage costs,while opting to encrypt image data before outsourcing to ensure image security and prevent privacy breaches.However,encrypted image data lose the correlation between clear text characteristics and data,affects the user's management of image data,and makes it impossible to retrieve images efficiently.Although encrypted indexes can be constructed in advance and stored with encrypted images in a cloud server to ensure the security and availability of images,most encrypted image retrieval schemes today do not pay enough attention to malicious cloud services,which may return user errors or incomplete results.Because it is difficult to construct a common authentication structure to verify the similarity calculation process of image type data,it is very difficult to verify the results of encrypted image retrieval.Besides,to better reflect the user's true goals and points of interest,how to narrow the gap between image semantics and their feature descriptors,and better capture user interests is also a problem worth studying.In this thesis,the main research is to solve the problem of facing malicious cloud service threats in the process of encrypted image retrieval,while improving the retrieval efficiency and accuracy of image similarity comparison.To address these issues,the main contributions and innovations of this article are as follows:(1)To solve the malicious cloud server threat to avoid returning incorrect or incomplete search results,this demand resorts to blockchain technology,a blockchain-based verifiable encrypted image retrieval service scheme is proposed,which realizes the reliability of search results and the transparency of the search process.The scheme stores the encrypted index on the blockchain(Ethereum),through the consensus mechanism of blockchain to ensure that the function of completing the search on the smart contract achieves the completeness of the search results,and outsources the corresponding encrypted image data to the cloud server to reduce the storage cost,after security analysis and experiments show the reliability of the scheme,high retrieval efficiency,accuracy,and has a good privacy protection effect.(2)A double-layer index structure using visual word bag model and simhash is designed,the first layer is based on the visual word bag model method to determine the classification of images to reduce the amount of simhash calculation,the second layer is to use simhash for similar image retrieval,Hemming distance as an indicator to judge the similarity between images,using this index structure can not only refine the image classification but also improve the search efficiency and accuracy when comparing similarities.(3)By using encryption technology based on redaction policy attributes,data owners are allowed to authorize fine-grained searches for data users.The main idea is that the data owner encrypts search keys and index keywords according to the specified access policy,and the data user can perform a search on the encrypted index keyword only if the data user's attributes meet the access policy,thus enabling the management of search permissions.