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Research On Attribute-based And Homomorphic Cryptosystem In Cloud Environment

Posted on:2020-03-30Degree:MasterType:Thesis
Country:ChinaCandidate:Y Y WangFull Text:PDF
GTID:2428330590496498Subject:Electronic and communication engineering
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The technology of cloud computing has experienced rapid development since its emergence,leading to the advance of the related cloud industries.Cloud service providers allow users to adjust the amount of usage according to resource requirements,which makes the pattern of utilization more flexible.The powerful capabilities of storage and computing provide efficient and convenient services to the government,enterprises and individual users.Meanwhile,cloud services also strongly support the promotion of technologies such as the Internet of Things and big data.However,the cloud environment has not only advantages,but also risks.Secure cloud services need to address issues such as privacy leakage and attacks from internal and external,and ensure the confidentiality,integrity,and reliability of users' data.Therefore,it is of great academic significance and application value to research the cryptosystems and its application which are more applicable to the cloud environment.The attribute-based encryption algorithm has some favorable characteristics such as anonymity and one-to-many.The homomorphic encryption algorithm can implement confidential computing.Both of them have important applications in privacy-preserving and information security in the cloud environment.This paper respectively research this two encryption algorithms,and instantiate the application examples in the actual scenarios furthermore.The contributions are two-fold:(1)In the traditional access control and data sharing schemes using ciphertext-policy attribute-based encryption,the access policy is publicly transmitted with the ciphertext in plaintext form.However,the access structure can also leak sensitive information of users in most cases.Although the existing policy-hiding schemes have improved in security of algorithm and expression ability of access policy,they do not solve the problem that how to verify whether users have authority to decrypt the ciphertext because the policy is hidden.In this paper,I propose a ciphertext-policy attribute-based encryption with hidden access policy based on LSSS access structure,which can hide the whole attributes(rather than only its values)in the access policies,meanwhile,I use cloud-assisted Bloom filter and the reconstruction of the full-rank sub-matrix to achieve efficient and accurate evaluation of decryption authority,which makes data decryption easier.Taking advantage of verifiable outsourcing computation services balances security and efficiency of this scheme.Security analysis using dual system encryption show that this new scheme achieves adaptive secure against chosen-ciphertext attack in the standard model.At last,it can be well applied to practical scenarios such as privacy-preserving user-matching in social networks.(2)The popularity and widespread use of cloud servers provides new approachs when we solve some traditional problems.Introducing cloud assistance to secure multi-party computing can effectively reduce the cost of computation and communication of terminal equipments on one hand,and in the meantime bring security privacy-preserving issues on the other hand.This paper proposes a cloud-assisted general secure multi-party computing scheme based on multi-key homomorphic encryption algorithm,which needs only 3 rounds of ineraction and can support dynamic participants.This scheme is very efficient,not only on account of the above reasons,but also because the NTRU algorithm is very fast in encryption and decryption.Using the thought of simulation paradigm,this protocol is proved secure in CRS model with semi-malicious settings.At last,the simplified version of this scheme and the Bloom filter are used to instantiate the application in the private set intersection.
Keywords/Search Tags:attribute-based encryption, multi-key homomorphic encryption, hidden access policy, Bloom Filter, decryption authority verification, NTRU, secure multi-party computing
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