Flexible and Efficient Blockchain-Based Cloud Storage
Ying-yu Pan, Yi Li, Ce-yu Gao, Li Fang, Ping Chen · 2021
Immutability is a vital feature of blockchain. The introduction of blockchain into cloud storage provides a trusted method for data verification. Data are stored on the cloud, while its hash is recorded in blockchain transaction which is accessible to everyone. However, it also brings much inconvenience to data modification. For any change of data, the hash would become different. The data owner needs to update the whole data that is stored on the cloud and create another new blockchain transaction for the new data hash, which causes lots of extra costs. It is impractical when there is a need for frequent data modification. Therefore, we put forward a new scheme that makes blockchain-based cloud storage more flexible and efficient. Our approach designs the Merkle Tree based on pairing-based Chameleon hash and describes in detail how to integrate it into blockchain to realize data storage, modification and verification in a reliable and less-cost way. Moreover, we encapsulate the related operations into a virtual machine (VM) to improve the performance of the system. We also provide a real implementation of the scheme. The experimental results and comparison show that the proposed scheme is practical and efficient.