Research On User Behavior Audit Of Encrypted Database Based On Searchable Encryption Technology

In the era of big data,as the most important carrier of data,the security of databases is increasingly valued by government and enterprise units.As a real-time and efficient technology to ensure database security,database auditing technology plays an increasingly important role in the current network security technology.With the emergence of searchable encryption technology and homomorphic encryption technology,blockchain technology has been successfully applied to various scenarios.Applying searchable encryption technology and homomorphic encryption technology to the database audit system can effectively reduce the difficulty of auditing ciphertext data and improve the efficiency of auditing ciphertext data.Therefore,ciphertext database auditing technology based on searchable encryption,homomorphic encryption and blockchain technology has become an important research direction of database auditing technology.With the rapid development of Internet technology and frequent information security incidents,users increasingly value the privacy and security of personal data,leading to more and more encryption technologies being applied,greatly increasing the difficulty of data auditing.This article uses searchable encryption algorithm based on symmetric encryption,homomorphic encryption algorithm based on symmetric encryption,and hyperledger technology based on blockchain,and expands from three aspects: audit log algorithm,ciphertext data retrieval algorithm,and distributed database audit server design.Research on the audit of ciphertext data.The main research contents of this thesis are as follows:(1)Aiming at the difficulty of data auditing in user encrypted transmission data,a database audit log based on searchable encryption is proposed.According to all the user's actions on the database,the audit server builds a database audit dictionary.The client automatically forms an audit keyword group according to its own behavior of adding,deleting,modifying and checking the database server.By executing the trapdoor generating function of the searchable encryption algorithm on the audit keyword group,it generates an audit certificate that is convenient for auditing.The audit algorithm will be passed on the audit server.Comparing calculations and database audit dictionaries to obtain corresponding database audit keywords to complete user behavior audits.(2)When the audit server traces the source of user behavior and data,it is difficult for the audit server to retrieve the ciphertext stored in the database.To solve this problem,this thesis proposes a ciphertext database retrieval technology based on a homomorphic encryption algorithm.When the user stores data in the database,the data vector generated based on the data characteristics is executed by the homomorphic encryption algorithm to obtain the ciphertext vector and stored in the database.When auditing the data source,the auditor will need to obtain a retrieval license from the user,and then execute the homomorphic encryption algorithm to generate the retrieval vector for the audit information that needs to be retrieved.The database server calculates the correlation coefficient between the retrieval vector and the ciphertext vector,and finally makes the auditors Able to accurately locate ciphertext data.(3)In order to prevent the audit server itself from being exposed to internal attacks or external penetration attacks and tampering with audit data,this thesis proposes an audit server scheme based on blockchain.Based on the idea of consortium chain,this article uses Hyperledger technology to install virtual machines in the audit server,build distributed nodes,transplant the audit code and related algorithms in the audit server into smart contracts,and write data collection interfaces and front-end interfaces to make Relevant audit data can be displayed to auditors normally.