Research On Secure And Trusted Data Sharing Scheme Based On Blockchain

Cloud services can provide users with almost unlimited storage space and computing resources,which provides an important infrastructure for the development of data sharing.However,due to the potential security threats in cloud services and the incomplete credibility of service providers,some new security challenges have emerged in cloud-based data sharing,which are mainly reflected in the following two aspects:the privacy issues of the data storage and sharing process and the credibility of user's retrieval results.In the era of big data,data is regarded as personal property,and users do not wish their data to be leaked,thus posing a threat to personal privacy.At the same time,in the process of data sharing,due to the sensitivity of query requests,the leakage of query requests will also seriously threaten the privacy of users.Therefore,how to ensure the privacy in sharing of data is a very critical issue.Secondly,due to network failures,service exceptions,or even dishonest execution of cloud servers,the retrieval results will be incorrect.Therefore,the realization of secure and credible data sharing is still a hot research topic in the current data sharing field.Data encryption is a fundamental method to protect the security of data.Realizing efficient retrieval to ciphertexts provides a feasible method for solving the contradiction between data security,privacy,and availability.As a key technology of Bitcoin,blockchain is complete decentralization.Its transaction contents cannot be tampered with and are publicly verifiable,and its unique chain structure can also trace the transaction.Blockchain can realize credible transactions in a network environment where there is no trusted third party.It provides a new opportunity to solve the security of data sharing and the credibility of data retrieval,which has attracted extensive attention in various fields,such as finance,medical treatment,and education.In this paper,we present two secure and trusted data sharing schemes based on blockchain,which not only realizes the protection for data security and query privacy but also realizes credible verification to data retrieval results without relying on any trusted third parties.The main research contents of this paper are summarized as follows:1.Based on the ciphertext policy attribute-based encryption(CP-ABE),public key searchable encryption,and blockchain,we propose a security and trusted multi-user authorized data sharing scheme in this paper.(1)Realize data security protection,access control,and multi-user data sharing through CP-ABE,and reduce the storage,computation,and communication overhead caused by repeated encryption of data owners.(2)Utilize the searchable encryption with keywords to realize privacy protection for data query requests,and improve the efficiency of ciphertext retrieval.(3)Transfer the execution process of ciphertext retrieval from the cloud server to the blockchain and verify the digital signature to ensure the correctness and completeness of ciphertext retrieved results.2.Based on the invertible bloom filter(IBF),k-out-of-n oblivious transfer(OT_n~k),symmetric searchable encryption,and blockchain,we propose a security and trusted verifiable dynamic data sharing scheme in this paper.(1)Store the IBF on the blockchain to verify the correctness and completeness of the retrieved results returned by the cloud server without the help of any trusted third parties.(2)Ensure that the verification result is still correct after the database is updated,and the cloud server's dishonesty behavior can be called to account.(3)EmployOT_n~k to realize the interaction between the data owner and the data requester,ensure that the data requester can obtain the corresponding decryption keys from the data owner without compromising the privacy of the query.