Blockchain-Based Decentralized Public Auditing for Cloud Storage
ABSTARCT :
Public auditing schemes for cloud storage systems have been extensively explored with the increasing importance of data integrity. A third-party auditor (TPA) is introduced in public auditing schemes to verify the integrity of outsourced data on behalf of users. To resist malicious TPAs, many blockchain-based public verification schemes have been proposed. However, existing auditing schemes rely on a centralized TPA, and they are vulnerable to tempting auditors who may collude with malicious blockchain miners to produce biased auditing results. In this paper, we propose a blockchain-based decentralized public auditing (BDPA) scheme by utilizing a decentralized blockchain network to undertake the responsibility of a centralized TPA, and also mitigate the influence of tempting auditors and malicious blockchain miners by taking the concept of decentralized autonomous organization (DAO). A detailed security analysis shows that BDPA can preserve data integrity against tempting auditors and malicious blockchain miners. A comprehensive performance evaluation demonstrates that BDPA is feasible and scalable.
EXISTING SYSTEM :
? Every existing system uses rewards to encourage peers to participate in the storage process honestly.
? We assume that leaders act in a rational manner, broadcasting new blocks as soon as they are ready. This is a common behavior presents in most of the existing blockchains.
? On the other hand, in a permissioned setting, nodes must be authorized and sk allows them to authenticate in the system. Revealing sk would allow an attacker to maliciously act in its name and breaks any existing contractual agreement.
? Naturally, as already described, Audita can be implemented by modifying the protocol of an existing blockchain.
DISADVANTAGE :
? The emergence of blockchain technology provides a new research idea to solve the problem of mutual trust. It utilizes cryptography rather than centralized architecture to build trust in peers for safeguarding interactions of them.
? If it is not equal to the hash value stored in the block body, the file is considered to be damaged.
? This shows that with the increase of files’ sizes, the impact of the network’s I/O on the system is greater than that of waiting for packing into a block.
? Suppose a malicious user change the data of the previous block, it will inevitably cause the hash change of this block, furtherly result in the inconsistency between the hash of previous block and the prehash of current block.
PROPOSED SYSTEM :
• This paper proposed a public auditing scheme with the blockchain technology to resist the malicious auditors.
• The proposed schemes introduced above have the same problem: the client needs to access the complete data back-up; however, it is not suitable in practice obviously as mentioned before.
• In the practical applications, the integrity checking task is performed by the TPA and most of the schemes proposed later support public auditing.
• Through the analysis above, we can see that the proposed schemes have the following defect present: the security of these schemes relies on the trusted third party—TPA.
ADVANTAGE :
? We developed a prototype on Ethereum platform using Aliyun as data storage service and test the performance of uploading and download different size of file.
? Since the capacity of a block is limited in the blockchain, only very important security information is considered to store into the block, or system performance will not be acceptable.
? However, it is inefficiency to analyze users’ operation from large amounts of system log records.
? The chained metadata information can later be used for data integrity verification, the chained operation record can later be used for tracing access to file.
? Metadata information can later be used to conduct integrity auditing, behavior auditing can be conducted by analyzing the operation logs.
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