Research On Secure Deletion For Cloud Storage

As a new storage service model,cloud storage makes data storage and data sharing more convenient and economical.However,due to the separation of ownership and management of outsourced data and the existing logical deletion mechanism,it is easy to expose data to unauthorized users,and it is difficult to guarantee the secure deletion of outsourced data.In recent years,many secure data deletion proposals have emerged,but they are either based on the assumption that the cloud server is completely trustworthy,or based on trusted third-party with high construction costs.In addition,few schemes take into account features such as public verification,and cannot guarantee the correctness of the deletion results and the traceability of the server or the data owner in the event of malicious intent.Therefore,this paper studies a safe and efficient cloud data deletion scheme based on blockchain technology.The main tasks are as follows:Firstly,considering the lack of fine-grained access control and deletion in many schemes that may cause cloud data to be leaked to users without access rights,and to ensure the correctness of the deletion results and the traceability of the server or the data owner maliciously,a scheme for secure storage and deletion of fine-grained cloud data based on blockchain is proposed.This scheme is based on ciphertext strategy-based attribute-based encryption constructed on the basis of elliptic curves to achieve fine-grained access control.The data owner of this scheme can specify users who access the ciphertext of the data;Further,the proposal uses blockchain technology to achieve publicly verifiable secure data deletion;secondly,the proposal has characteristics such as responsibility traceability,twoparty deletion and verifiability;Finally,from both theoretical analysis and experimental results,it can be reflected that the scheme has better security and higher performance,and can meet the needs of cloud data sharing and safe deletion.Secondly,considering the separation of ownership and management of outsourcing data and the existing logical deletion mechanism,it is easy to expose data to unauthorized users,the problem of multi-copy and multi-key management,how to delete all backups safely and the unreliable of cloud servers menaces users’ data security.A secure deletion scheme for multiple backups based on blockchain is proposed.This proposal provides multiple backup association security deletion features and adopts a hash chain method to reduce key management overhead;In addition,it uses merkel hash trees and blockchains to achieve public verification and responsibility tracking features;Farther,in order to avoid untrustworthy of cloud servers,searchable encryption features are added to the scheme;Finally,the security certification,security feature analysis and comparison of the calculation cost of the proposal show that the scheme has better security and performance.