Research Of Identity Based Encryption And Outsourced Encryption Scheme

An Identity-Based Encryption(IBE)system is a public key encryption system where it regards the user identity as public key.The user's private key is generated by a trusted authority,called a Private Key Generator(PKG).Therefore,the Identity-Based Encryption system eliminates the drawback of certificate management and secure channel in the traditional public key encryption system.But its shortcomings is that the system security depends on the security of PKG and the system has enormous burden of computing for single PKG because its private key is generated by PKG.In order to solve these problems,the Hierarchical Identity-Based Encryption(IBE)system is presented.The Outsourcing Encryption achieves the method in which cloud server performs the work that needs a great amount of calculation and user has a little bit of computing burden.In order to overcome the drawback of partitioning strategy when the security of system is proved,the Dual System Encryption techniques is presented.The techniques prove system security by proving the indistinguishability of a series of games.Its advantages are that the simulator doesn't need to divide into the identity space and the techniques can be used to prove the security of Hierarchical Identity-Based encryption and Attribute-Based encryption.The work of this paper is divided into three parts: Firstly,this paper presents a ciphertext-policy attribute-based encryption system with outsourcing decryption method in which cloud server performs the work that needs a great amount of calculation when the user need to decrypt and the user has a little bit of computing burden.Secondly,this paper improves a hierarchical identity-based encryption(HIBE)system.To the best of our knowledge,our construction is the first HIBE system that achieves both full security in the standard model and short parameters in terms of public parameter,private key,and ciphertext.Thirdly,this paper presents an efficient identity-based encryption system that has efficientcomputing efficiency,short public parameters and compact security proof and achieves the anonymity.The security of scheme is proved under three static assumptions.Finally,the three systems all are prove fully secure by the dual system encryption techniques.In this paper,we propose three encryption scheme's works based on the study of Identity-Based Encryption(IBE)system,in which many contents are involved,including outsourcing encryption scheme,hierarchical identity-based encryption scheme,attribute-based encryption,dual system encryption techniques and anonymity.They are described in detail in this paper and we obtain the corresponding results by some experiments.