Research And Implementation Of Blockchain Technology In Secure Cloud Storage

The implementation and application of cloud storage technology provide users with a new data processing mode.Its convenient and efficient features attract more and more individuals and groups to store data in the cloud storage system.At present,cloud storage technology has problems such as open environment and centralized processing,which pose a great threat to data and user security.The rise of blockchain technology has given new ideas for solving security problems in cloud storage technology.Blockchain-based data storage schemes are emerging in an endless stream.This paper researches two problems that currently exist in blockchain-based storage systems: storage encoding schemes are separated from blockchain technology,and there are privacy leakage in attribute-based access control schemes.The corresponding solution is provided and the main work is as follows:1.Aiming at the problem of the low degree of combination of storage code and blockchain network in blockchain-based data storage scheme,a blockchain-based pipelined coding scheme is proposed.This solution takes advantage of the strong plasticity of the virtual chain in the double-layer blockchain architecture to realize the deep integration of the blockchain network and the pipelined code scheme and uses the high-security features of the public chain to protect the security of the virtual chain and realize the decentralization and anonymization of the system.The scheme fully utilizes the decentralized characteristics of the blockchain in the encoding process to improve the security and efficiency of storage encode.At the same time,the encoding scheme is combined with a time-based copy storage mechanism to balance the storage overhead and computing overhead of the system.2.Aiming at the problem of leakage of user attribute privacy and policy privacy in the attribute-based access control scheme in the blockchain-based data storage scheme,an attributebased access control scheme based on cryptographic accumulators deployed on the smart contract is proposed.This scheme utilizes the features of cryptographic accumulators to accumulate proof for members to achieve protection of user privacy and policy privacy during access control.At the same time,we use the trigger execution features of smart contracts to achieve automatic execution of strategies;and use smart contracts can be revoked,the mechanism supports user attribute revocation and strategy update.3.Designed and implemented a blockchain-based secure cloud storage prototype system that implements basic data upload,download,and sharing functions.The system realizes the decentralized storage of data,which can adjust the degree of redundancy of data storage according to user needs and can also achieve fine-grained access control of data according to the access control strategy formulated by users.According to theoretical analysis,it can be seen that the system has high security.Finally,we conducted simulation experiments on the system on the experimental platform to test the performance of the prototype system.According to the experimental results,this system has a better performance in terms of efficiency.