Research And Implementation Of Searchable Encryption In Cloud Environment

Cloud computing technology,a sharing pool for computing resource,provides users with computing,storage and other services.As the cloud computing service providers are not entirely credible,the data stored in the cloud need to be encrypted,which leads to the demand of how to retrieve data in ciphertext.To this end,searchable encryption technology emerges as required which can find the desired data for users without decrypting.However,with the development of big data and artificial intelligence,more and more data are outsourced to the cloud for storage,new requirements are put forward for searchable encryption technology,such as more efficient retrieval targeting multiple keywords,sequencing searching results,etc.In order to solve the above problems,in this thesis the searchable encryption based on symmetric cryptosystem and asymmetric cryptosystem is deeply researched respectively.The advantages and disadvantages of the existing schemes are analyzed in detail,on which basis the shortcomings of the schemes are improved.As a result,searchable encryption schemes that meet the security demand based on bilinear mapping and symmetric cryptosystem are designed respectively.Our work is as follows:First,an asymmetric searchable encryption scheme based on BDH problem is designed,which not only supports the application of multiple keywords,but also supports the query of fuzzy keywords.The scheme is proved under the random oracle model.Compared with the existing schemes,the proposed scheme not only guarantees favorable security,but also has higher efficiency.After that,a searchable encryption scheme based on symmetric cryptosystem is designed,which adds the function of sequencing the searching results according to the degree of correlation on the basis of multi-keyword and fuzzy keyword queries.The scheme,based on AES encryption algorithm,ensures the efficiency of data encryption and the security of ciphertext.Finally,the two proposed schemes are implemented in Java environment with j PBC library.The experiment shows that the functions of the the proposed scheme are helpful to the functional expansion and efficiency improvement of searchable encryption technology.