基于TBchain区块链的高可信云存储模型

High Trusted Cloud Storage Model Based on TBchain Blockchain

云存储中的数据可能会遭受非法窃取或篡改,从而使用户数据的机密性面临威胁。为了更加安全、高效地存储海量数据,提出一种支持索引、可追溯、可验证的云存储与区块链结合的存储模型CBaaS(Cloud and Blockchain as a service),它可以增强云中数据的可信性。另外,区块链的协商一致协议导致交易的吞吐量低,处理速度慢,严重制约了去中心化应用的发展。基于此,文中实现了一个三层架构的区块链模型TBchain(Three-tier architecture Blockchain),其通过分割区块链的一部分并将其锁定在更高级别区块链的块中提高区块链的可伸缩性,从而提高区块链中交易的吞吐量。此外,区块链由于去中心化的需求占用了海量节点的大量存储空间,这极大地限制了以区块链技术为基础的数据库系统的发展与应用。通过TBchain将一部分交易存储在本地,增加了区块链存储容量的可扩展性。云存储对象元数据中的ETag标示一个Object的内容,可以用来检查Object内容是否发生变化。将云存储中的对象元数据存储在区块链上,利用ETag值可以用于检查Object内容是否发生变化的特性和区块链上的数据不可篡改的特性来验证云上存储的数据是否安全,从而提高云上存储数据的可信性。实验结果表明,TBchain模型提高了区块链的可伸缩性和区块链存储容量的可扩展性,CBaaS模型也有效地提高了云上存储数据的可信性。

Data stored in the cloud can be illegally stolen or tampered with,exposing users’data to confidentiality threats.In order to store mass data more safely and efficiently,this paper proposes a storage model CBaaS(Cloud and Blockchain as a service)that supports the combination of index,traceability and verifiability of Cloud storage and Blockchain,which can enhance the credibility of data in the Cloud.Secondly,blockchain consensus protocol leads to low throughput and slow processing speed of transactions,which seriously restricts the development of decentralized applications.Based on this,this paper implements a three-tier architecture Blockchain model TBchain,which improves the scalability of the Blockchain and the throughput of transactions in the blockchain by dividing a part of the blockchain and locking it in the block of a higher level blockchain.Next,due to the demand of decentralization,blockchain occupies a large amount of storage space of massive nodes,which greatly limits the development and application of the database system based on blockchain technology.Part of the transaction is stored locally through TBchain,which increases the scalability of blockchain capacity.The ETag in the cloud storage object metadata is used to identify the contents of an Object and can be used to check if the contents of the Object have changed.By storing the object metadata in the cloud storage on the blockchain,the ETag value can be used to check whether the content of the Object changes and the data on the blockchain can not be tampered with to verify whether the data stored on the cloud is safe and improve the reliability of the data stored on the cloud.The experimental results show that the TBchain model improves the scalability and storage capacity scalability of the blockchain,and the CBaaS model also improves the reliability of data stored in the cloud.