Predicate Ciphertext Indexing Scheme Based On Paillier Algorithm

Due to the advent of the era of big data,a large number of storage resources are stored in the database.Although diversified services are provided to users,database leakage events often occur.Although users can ensure the security of sensitive data after encrypting by traditional methods,the ciphertext retrieval is very complicated,and it is impossible to calculate the ciphertext data directly.Therefore,an effective retrieval scheme must be designed.In this paper,by analyzing the efficiency of ciphertext retrieval,a secure retrieval scheme based on homomorphic encryption is designed to ensure the efficient ciphertext retrieval in the untrusted storage environment,without leaking any information related to plaintext,and at the same time,users can access the data with fine granularity.Aiming at the low efficiency of ciphertext indexing in homomorphic algorithms,this paper proposes a predicate ciphertext indexing scheme based on Paillier algorithm.In this scheme,the plaintext data is converted into character data through JIEBA word segmentation to select low-frequency word segmentation and UTF-8 transcoding to transcode Chinese characters,and then the deployed Paillier algorithm is used to encrypt the character data.Based on the homomorphism of the algorithm,the scheme can directly calculate the ciphertext.Finally,the correctness of the proposed scheme is tested,and its correctness and integrity are verified through the process of plaintext encryption and decryption.In addition,in order to satisfy the ciphertext data does not need to be packaged as a whole query,to achieve faster query retrieval,this scheme designs two kinds of predicate encryption based equivalent type retrieval algorithm and fuzzy retrieval algorithm retrieval algorithm.In the equivalent retrieval algorithm,the keyword information is encrypted first,and then the data satisfying the query conditions is transmitted back through matching with the ciphertext data in the database,and then the decryption operation is carried out.In fuzzy retrieval algorithm,also to encrypt the data first,then use jieba participle technology will determine the conditions for resolution,will split the data and database matching and back respectively,then on the client for the second match operation,improve the server-side filtering of invalid data,reduce the waste of the retrieval time,achieve relatively fast index,and the efficiency of the algorithm are verified by the experiment,found that the retrieval efficiency of the two kinds of retrieval algorithm is general good.