Research On Fuzzy Search Technology Of Ciphertext Data

With the development of cloud computing and cloud storage,When Individuals and companies has a large amount of data,they will very likely choose to store data in the cloud in order to save storage resources.However,It is not safe to store the data directly into the cloud,in order to ensure the security of the data,they will first encrypt the data before upload to the cloud.At this point,it is needed to solve the problem of how to retrieve the encrypted text.searchable encryption schemes is proposed by Song et al.Therefore,on this basis,we study the fuzzy retrieval technique of the encrypted data.We found that there are many security problems in traditional index.In order to compensate for the lack of traditional indexes,we designed a new ciphertext index structure.The cipher text index based on the inverted index.In order to ensure the security of the index,we encrypt the key words,inverted items and other information.Further,in order to improve the retrieval efficiency,we use counting bloom filter(CBF)for keyword search.Through these improvements,we guarantee the security of the cipher text index,and improve the efficiency of the retrieval.In order to realize the fuzzy search.Firstly,we study the existing fuzzy search techniques Deeply.Then combined with the characteristics of Chinese,We have designed a new edit distance.The new edit distance by pinyin and synonyms together.Finally,we realize the construction algorithm of Chinese fuzzy set.When the algorithm is used in fuzzy search,It can improve recall and precision,reduce the size of fuzzy set.In order to get a better user experience,We propose a fusion correlation ranking algorithm before the system returns a result set to us.The algorithm is composed of edit distance,TF-IDF weight,and heat,through these three aspects of the document scoring.Where,Edit distance reflects the user's intention,TF-IDF weights reflect the importance of keywords in the document,The heat reflects the freshness and popularity of the document.By this way,Such result sets can better reflect the characteristics of the retrieval results.In order to ensure the security of the system in the cloud computing environment,we adopt an improved public key encryption scheme.Experimental results show that the proposed scheme can ensure the security of data.The scheme can achieve the expected effect.At last,we test the performance of the system.These experiments include tests the creation efficiency of the cipher text index,fuzzy search effect of the system,performance of fuzzy set construction algorithm etc.