| The rapid development and accelerated integration of cutting-edge technologies,such as the Internet of Things,Artificial Intelligence,and 5G,have given rise to the era of big data,where massive volumes,diverse types,and quick updates characterize data.In this environment,cloud computing,serving as a resource-sharing and service-delivery model,provides users with storage and computing services in an on-demand and easily scalable manner,achieving low-cost and high-performance data management and maintenance.However,the development of cloud computing has caused profound changes in the data landscape,leading to new features like the separation of data ownership and control and imbalanced computing and storage resources.Data faces challenges like corruption,loss,and unclear ownership,putting secure data storage under significant pressure.To cope with these challenges,blockchain technology has emerged as a promising solution.With its diverse elements,such as distributed consensus,smart contracts,and cryptography,blockchain possesses excellent characteristics such as decentralization,trustlessness,openness,transparency,and tamper resistance.It is a natural carrier and technical foundation for safeguarding data security and transmitting data value,which is of great significance in enhancing the security,reliability,and availability of cloud storage.Currently,there is no established standard or technical system for the integration of blockchain and secure data storage.As a result,enhancing the security,reliability,availability,transferability,and editability of data,and achieving verifiable storage and full updating of data still face many difficulties and challenges.In this thesis,we focus on the secure storage requirements of dynamic large-scale data in big data environments,with the goal to enhance the reliability,usability,and accessibility of data,to explore issues concerning verifiable auditing and full updating of data,including:(1)how to ensure the integrity of outsourced data with ownership transfer;(2)how to optimize the recoverability and availability of outsourced data;and(3)how to achieve editability of data in blockchains.In summary,the main contributions are as follows:1.We propose a secure cloud auditing protocol with efficient ownership transfer,addressing the issues concerning incompleteness and low efficiency in transferring ownership of verifiable outsourced data.Specifically,we construct a novel verifiable data tag structure based on the 6)-CEIDH(6)-Computational Exponent Inverse DiffieHellman)assumption and designed an ownership transfer algorithm using the proxy re-encryption technology.Such a protocol achieves optimal computational cost and constant communication cost,and is secure against collusion attacks,enhancing mutual trust between users across trust domains during ownership transfer.(Chapter 3)2.We propose a blockchain-based accountable auditing protocol with multi-ownership transfer,which addresses the issues of lacking of ownership transfer algorithms for verifiable multi-owner data and the accountability of data disputes.Specifically,based on the combination of compact multi-signatures with public key aggregation and homomorphic authenticators,we construct a specific verifiable tag structure for multiowner data,satisfying both transferability and auditability simultaneously.Apart from that,the distributed ledger technology is used to record events related to data outsourcing and ownership transfer,thereby achieving accountability in data disputes and further promoting the standardization of outsourced data management.(Chapter 4)3.We propose a public proofs of data replication and retrievability protocol with userfriendly replication,coping with the issues concerning expensive overhead on clients in replication and unsatisfying recoverability upon corruptions of outsourced data.Specifically,we design a user-friendly replication algorithm through RSA-based timelock puzzles,which overcomes the efficiency bottleneck of precomputing copy parameters,achieving nearly no computation and a constant-size communication cost on cloud clients.With such a replication algorithm,we utilize non-interactive succinct proofs to make the verification of proofs of data replication and retrievability public,enhancing the transparency and trustworthiness of verification results.(Chapter 5)4.We construct a verifiable and redactable blockchain with full editing operation for the first time,dealing with the issue concerning the absence of a comprehensive method for fully updating of blockchain data and the coexistence of multiple versions of blockchain states.Specifically,we achieve the full redactability of block content by using a double trapdoor chameleon hash family,realizing key-exposure resistant and efficient redactions.Furthermore,we employ the largest sequence number principle as the state consensus,which is combined with a trapdoorless universal accumulator to achieve verifiability of the blockchain state and effectively address the issues of lazy update and history replay in existing redactable blockchains.(Chapter 6)... |
