Research On Black-Box Traceable Multi-Authority Attribute-Based Encryption With Hidden Policies Scheme

With the continuous development of the Internet,cloud computing and big data have become the hot technologies in the current society,which generate more complex security,requirements in data storage,data transmission,access control,and other aspects.In the traditional attribute-based encryption,attributes are managed by a trusted key generation center,and hence there exists a key escrow problem.If a user’s private key is leaked,the identity of the malicious user whose private key is leaked cannot be tracked effectively.Existing multi-authority attribute-based encryption schemes can effectively alleviate the key escrow problem and avoid the monopoly problem of a single authority.For traceable attribute-based encryption,white-box traceable model means that the malicious user who leaks the private key directly sells the decryption key.In contrast,black-box traceable means that the decryption key and decryption algorithm are hidden in the black box.In real-world applications,the attributes of an access policy usually contain user-side sensitive information.Therefore,how to realize privacy-aware of data sharing is also a research focus in recent years.However,there are still few attribute-based encryption schemes supporting hidden policies,misbehavior traceability,and multi-authority.To solve the above problems,the main contributions of this thesis are as follows:(1)We proposed a black-box traceable muti-authority attribute-based encryption scheme(BT-MABE).In this scheme,the key escrow problem caused by a single authority is effectively solved by introducing multiple central authorities(CAs)and multiple attribute authorities(AAs);The scheme can efficiently trace the identities of malicious users whose private keys are leaked according to the decryption black-box.(2)We proposed a policy hiding black-box traceable muti-authority attribute-based encryption scheme(HBT-MABE).Based on the BT-MABE scheme,the tecinic of policy partly hiding is adopted.Attributes are divided into two parts:attribute name and attribute value.The privacy of users is protected by hiding the attribute value.(3)Formal security proofs shows that the proposed schemes achieve adaptive security against the chosen plaintext attack(CPA),policy hiding and traceability under the standard model.Performance analysis and experimental simulations show that the proposed schemes are efficient and practical in terms of computation and communication overhead.