Research On Forward Secure Dynamic Symmetric Searchable Encryption

Maturity of 5G technology inspire rapid development of big data in the information era.Massive data are produced and processed everyday,by individuals and business.Con-sidering the limitation of local storage and computing ability,the vast majority of users outsource their dataset to cloud server,which will cause leakage of private data for clients.A naive approach to solve this problem is encrypting private data before uploading them.Unfortunately,storage in ciphertext will reduce data availability.Search operation cannot be done directly on ciphertext,because of the index privacy.Dynamic searchable encryp-tion provides not only keyword-searching on ciphertext,but also the ability of inserting and deleting documents.Most of existing dynamic searchable encryption schemes which support efficient search operation are not forward-secure,which means they cannot resist file-injection attacks.Based on the research on dynamic symmetric searchable encryp-tion,this paper proposes two forward-secure dynamic symmetric searchable encryption(DSSE)schemes from the perspective of reducing user storage overhead and improving server I/O efficiency,while ensuring efficient search operation.Main contributions of this paper are as follows:· To reduce user storage overhead,List-f DSSE,a forward-secure dynamic symmetric searchable encryption scheme,is proposed.This scheme combines forward index and inverted index to create a new encrypted index table,and uses the idea of linked list to achieve forward security while ensuring high search efficiency.In order to further enhance the security,we then proposed an improved scheme that also meet backward security.In the end we implemented our scheme and proved its security.· For improving server I/O efficiency,Fast-f DSSE,a forward-secure dynamic sym-metric searchable encryption scheme for efficient I/O is proposed.This solution uses an indented two-dimensional table,which consists of dynamic array set,to construct the index table,and stores the encrypted data related to a same keyword into a continuous storage space to optimize I/O efficiency when the server performs a search.We also use both immediate and original keys to ensure forward secu-rity.Once the keywords are searched,new immediate keys are generated to encrypt all subsequently added indexes.Finally,we analyze and prove that our scheme is forward secure,and analyze the efficiency.