Research On Attribute-based Encryption Scheme With Hidden Access Policy And Its Application

Attribute-based cryptography technology bind attributes with an access policy that performance ensure information confidentiality and achieve flexible communication mode.Hybrid encryption protocol combined with symmetric cryptography and attribute-based cryptography to improve efficiency of computation and feasibility and complex of the key management in practical applications.In most traditional attribute-based encryption schemes,encryptor often sends ciphertext to decryptor along with an access policy,but sometimes the access policy itself contains privacy information.And the problem that user and untrusted cloud storage service center will get related information about encryption by analyzing the access policy and know the identity of eligible user is solved.So there is increasingly significance that research on attribute-based encryption scheme with hidden access policy.The main study work of this thesis is as follow:(1)This paper proposes a new anonymous ciphertext-policy attribute-based encryption scheme over a prime order bilinear group,which is based on access tree by using asymmetric bilinear pairings.This new scheme hide access policy in ciphertext by CP-ABE,which comes to protect the plaintext and hides the access policy and relies on the DBDH-3 assumption is proven to be fully secure under standard model.(2)The scheme of attribute-based encryption with hidden access policy achieves attribute revocation and hidden access policy by the technique of proxy re-encryption under bilinear group based on AND-gates access control structure.Compared with similar schemes,the proposed scheme not only achieves hidden access policy and attribute revocation,but also improves the efficiency of computation and feasibility while reducing key and ciphertext length.In addition,the scheme is proved to be safe under standard model when using Decision Bilinear Diffie-Hellman assumptions.(3)In order to improve the security of cloud storage service,the new cloud storage model connect with cloud storage of hybrid encryption and anonymous ciphertext-policy attribute-based encryption supporting by attribute revocation.Finally analyze the advantage about protecting privacy and data security.