Research On Secure Sharing Of Encrypted Data In Cloud Storage

With the rapid development of computer technology and network technology,distributed methods of storage and computation are accepted by more and more people.The development and application of these technologies have promoted the development of cloud computing services characterized by professional and flexible services and integration of virtualized resources.However,the security of cloud storage data sharing is the key to cloud computing services.Due to the separation of data owner and management rights,as well as the fact that cloud service providers are not fully trusted,cloud data sharing methods have some challenges,such as user privacy leaking,the confidentiality and integrity of shared data being destroyed,and the excessive computing load of users in sharing and accessing.Faced with these challenges,many researchers have done a lot of research,but these problems have not been completely solved which still affecting the promotion and use of cloud computing services.Therefore,it is of great significance to study cloud storage data sharing methods which have more security and efficiency to make cloud computing more convenient for social production and people's lives.The main research work of this paper includes:1.This paper expounds the research background and significance of data sharing methods in cloud storage,elaborates the existing security problems in cloud storage data,and summarizes the research status of data sharing methods in cloud storage at home and abroad.The cryptography related knowledge such as group theory,bilinear mapping and group signature are introduced.Several typical attack models and difficult problem assumptions are also introduced.2.This paper studies the cloud data security sharing method to solve the problem that users have excessive computing load in multi-user data sharing methods,and users' identity information leaks.The method is designed with anonymous user list to protect users' privacy information and improve key generation,encryption and decryption.It can reduce the cost of computation and storage.This paper analyses the security and the efficiency of the method.3.Considering that privacy information is easily leaked from public attributes and the computation is large in encryption and decryption phase in hybrid cloud environment,this paper proposed a solution to share data safely in group.Replacing attributes with corresponding values for blinding attribute names,the privacy problem above is solved.With the help of the outsourcing technology,a large amount of computation is transferred from user to cloud servers.Through designing and analyzing the comparison experiments,the encryption and decryption efficiency of the method are verified.The innovations are listed as follow:1.An improved method is proposed for sharing data between multiple users in cloud storage environment.The security analysis shows that the method holds the following properties: identity fraud resistant,illegal access resistant,malicious users tracing and non-repudiation of data owner.The efficiency analysis shows that this method can reduce the computing and the storage cost on the client.In detail,this method reduces 81.6% and 14.2% of the storage cost on the client and group,respectively.Moreover,it can work in the many-to-many sharing mode and is suitable in the computation limited scenario.2.A safe and efficient method is proposed for group data sharing in hybrid cloud environment.The security analysis shows that this method can satisfies the following functions: user identification,attribute security,malicious users tracing,user legitimacy validation and data possession provability;In addition,the performance analysis states that it can achieve the revocation of user and attribute,attribute hiding,computing outsourcing and fine-grained access control;In the end,the experimental results implies that this approach outperforms the baselines on the aspect of the encryption and decryption efficiency ignoring the number of attributes,so it is suitable for sharing data in multiattributed group.