Research On Anonymous Attribute-based Encryption For Privacy Preservation In Cloud Storage

Data sharing is convenient and economic service supplied by cloud computing.Data contents privacy also emerges from it with privacy leaks occurring frequently.To protect the valuable and sensitive information,various techniques are used to enhance access control on the shared data.In these techniques,ABE can make it more convenient and secure.This thesis focuses on data privacy preserving,it proposes attribute-based encryption with hidden access policy.The main work accomplished are as follows:1.An attribute-based encryption scheme with hidden access policy is proposed.Traditional CP-ABE focuses on data confidentiality merely,while user's privacy preserving has become an important problem.CP-ABE with hidden access policy ensures data confidentiality and guarantees that user's privacy is not revealed as well.However,most of the existing schemes are inefficient in communication overhead and computation cost.Moreover,most of those works take no consideration about authority verification or exist the problem of privacy leakage in authority verification phase.To tackle the problems above,a privacy preserving CP-ABE scheme with efficient authority verification is proposed.Additionally,the secret keys of the scheme achieve constant size which is independent with the number of attributes.Meanwhile,the proposed scheme is proved to be selectively secure under the decisional n-BDHE and decisional linear assumptions.The computational results confirm the merits of the proposed scheme.2.An attribute-based encryption promotion scheme with hidden access policy is proposed.Attribute-based broadcast encryption has a wide range of application scenarios,as it combines the advantages of attribute-based encryption and broadcast encryption.However,similar to the situation of attribute-based encryption,the problem of privacy leakage is also an emergency problem.To solve this problem,an attribute-based broadcast encryption scheme with hidden access strategy is proposed.The scheme is based on composite order bilinear group.What's more the access policy and broadcast set are hidden at the same time without loss of efficiency,and the privacy protection of the user is realized.In addition,the scheme supports flexible access structure and achieves full security under three static assumptions.