Research And Implementation Of Identity-based Online/Offline Secure Cloud Storage Audit System

The rapid development of information technology has enabled informatization to penetrate into people’s lives and brought great convenience to people’s lives and work.However,this also brings some problems.For example,traditional storage methods cannot meet people’s storage needs in the face of the explosive growth of digital information.With the rapid development of cloud computing,cloud storage has the advantages of high efficiency and low cost.More and more users choose to migrate data from local to the cloud and use cloud storage to store and share their own data.However,due to the outsourcing of data,users do not have actual control over the data,which creates some hidden dangers to data security,such as data integrity.The security problems faced by cloud storage data mainly include:1.Cloud service providers that are not completely trusted may conceal the damage or loss of cloud data to users.2.The user’s key may be leaked in a complex cloud environment,and the user’s key is the cornerstone of the security of the entire cryptographic system,and the leakage of the user’s key may cause data security to be threatened.Therefore,it is extremely important to design a public audit mechanism for the integrity of cloud storage data.Provable Data Possession（PDP）protocol enables data owners to review the integrity of their outsourced data without downloading all the data.At present,most of the existing PDP schemes rely on the public key infrastructure,and the authenticity of the public key is ensured by the digital certificate provided by the certificate issuer.Therefore,the verifier needs to check the validity of the public key certificate before using the public key,but complex certificate management requires a lot of computing and storage resources.The identity-based cryptographic system eliminates the additional costs caused by the PKI architecture.How to design a safe,practical and efficient identity-based cloud storage audit scheme has become one of the important research directions in the field of cloud storage research.This paper conducts research and analysis on the existing identity-based online/offline cloud storage audit scheme.The main work done is as follows:（1）In the research of identity-based cloud storage auditing system,the identity-based online/offline cloud storage auditing scheme proposed in[38]is analyzed.The analysis results show that the[38]scheme cannot meet the robust security requirements.When you have any two message blocks and their verification tags,you can calculate the user’s private key.Therefore,the cloud server can use the user’s private key to forge a legal possession certificate for any audit message and pass the TPA verification.That is to say,even if the cloud server does not completely save the user data,it can generate a legal verification certificate and pass the integrity verification.The scheme proposed in literature[38]has security problems.（2）By analyzing the security of the scheme proposed in the literature[38],we put forward two efficient improvement schemes on the basis of the original scheme,and analyzed the safety and performance of the two improvement schemes.In our scheme,set the verification label of the message block m_i asσ’_i=u_i^η(k_{I Di})^{mi+H1（nameli）},where u_i is an element randomly elected by the user,which is equivalent to the random prediction response of the H₀ unction.This value ensures that the attacker cannot manipulate it through an identity-based ignature scheme,So ensure the robustness requirements of the program.In the online alculation phase of the two schemes,users only need to perform a small amount of ightweight calculations,which greatly improves the computational efficiency,and the chemes can provide robust security requirements and avoid forgery attacks.Compared with he first improvement plan,the second improvement plan has more operations in the online hase,but the data transmitted in the verification phase is reduced,and it has better storage fficiency.（3）This paper rents a simulation cloud storage environment based on Tencent Cloud Server CMV Cloud Virtual Machine),and uses the lightweight cryptography package JPBC to develop the imulation system.The simulation system realizes the main functions of the cloud storage udit scheme proposed in this article,and can support users to perform file upload,data audit,nd download functions.Finally,based on the system,the proposed scheme is tested for erformance,combining the experimental results and theoretical content analysis.In other tages,the calculation cost of the improvement scheme proposed in this paper is roughly the ame as that of the literature[32],while the calculation cost of users in the online phase is reatly reduced,which improves the efficiency of data upload and has better efficiency in the ctual cloud environment.