| In this era of explosive data growth,how to share data securely and efficiently has become a hot topic of scholarly research.Traditionally,data has been shared by hosting or trading with a ’trusted’ third party.Although this is efficient,it often leads to data leakage during the sharing process,which triggers a "crisis of trust" between the two parties.With the advent of asymmetric encryption and cloud storage,more and more people are choosing to share their data by encrypting it and uploading it to the cloud,especially with the advent of Ciphertext Policy Attribute-Based Encryption(CP-ABE),which supports fine-grained access control and is widely used in commercial environments such as cloud storage,where the technology and functionality are becoming more sophisticated.However,it lacks the combination of functions and cannot be traced to ciphertext.The birth of blockchain makes data authentication and traceability possible,but the openness of blockchain itself requires sacrificing a certain degree of privacy.Therefore,combining blockchain with cryptography to enable data sharing is a key issue that needs to be addressed.This paper conducts an in-depth study on how to share securely,efficiently,supervisably,auditable and confirmable in today’s big data era,with the following main work and innovations:(1)Revocable and tracing Undeniable CP-ABE:In order to solve the current problem that CP-ABE only focuses on one of the key revocation or key traceability issues and lacks the combination between the two,which cannot fully guarantee the rights and interests of data owners,a ciphertext policy attribute-based encryption scheme(ru CP-ABE)with key revocability and traceability non-repudiation is proposed.First,the subset coverage technology is introduced into the traditional traceable CP-ABE key,and utag with the user’s unique identification information is embedded into the key to realize the revocation of the key.Secondly,in order to solve the problem that the traditional third party conspires with users to sell keys to obtain benefits,a distributed key distribution technology is introduced to distribute attribute sets to different attribute organizations.When users generate keys,they change from traditional one-party generation to multi-party to defend against collusion attacks.Finally,we reduce the security to the three-prime subgroup decision problem and prove that our scheme is safe under chosen-plaintext attack,and test the efficiency of our scheme by using the jpbc library of Java.(2)Data Rights Confirmation Scheme Based on Auditable Ciphertext CP-ABE in the Cloud storage Environment: Aiming at the source data insecurity problem existing in traditional data confirmation schemes,a data confirmation scheme based on ciphertext auditable Ciphertext Policy Attribute-Based Encryption is proposed.The information with the user’s unique identifier is encrypted by Paillier and embedded into the ciphertext,and then introduced into the public audit stage to audit the ciphertext.In this way,the plaintext confirmation form is transformed into the ciphertext confirmation form,which greatly reduces the risk of source data leakage.Experiments show that the efficiency of the scheme is not significantly improved compared with the original encryption.(3)Block Chain-based Regulable Data Sharing Scheme: In order to realize data sharing in a safe,efficient,regulated,auditable,and verifiable manner,a blockchain-based regulated data sharing scheme is proposed.First of all,in terms of encryption,choose the key revocable and retroactive undeniable ciphertext policy attribute-based encryption(ru CP-ABE)proposed by the innovation point 1 to ensure the traceability and revocation after the key is leaked.Secondly,with the introduction of the Consortium Blockchain,each organization that wants to participate must enter through the access mechanism,and a government regulatory agency is set up in the alliance chain to ensure that the data sharing process can be supervised.Then,aiming at the problem that a small number of groups or institutions outside the chain are unwilling to join the Consortium Blockchain,an evolutionary game data sharing model based on the Consortium Blockchain is proposed to encourage these groups or institutions to actively participate in the Consortium Blockchain.Finally,by building Hyperledger fabric on the Linux platform and deploying Caliper to test the throughput of the Consortium Blockchain and smart contracts,and use Matlab to test the influence of different parameters in the evolution model on the evolution results. |
