Research On Attribute Encryption Scheme Based On Lattic

The Ciphertext-policy Attribute-based encryption provides flexible access control based on the attributes of user roles.The data owner encrypts the data information by making access policies,while the data users only need to satisfy the access policies.This access mode makes the encryption of the cryptograph policy suitable for the existing data storage environment.With the advent of quantum computers,cryptography schemes constructed by traditional number theoretic problems are insecure.Lattice cryptography is an active anti-quantum cryptography,has sufficient security and can be combined with cryptographic policy attribute encryption schemes to construct more secure cryptographic policy attribute encryption schemes.Therefore,this thesis constructs three ciphertext policy attribute encryption scheme based on the lattice cryptosystem,and mainly does the following work.(1)For the existing ciphertext policy attribute encryption scheme,the single authorization center needs to generate system parameters and is responsible for generating the user’s attribute private key,which causes the overload problem.Based on the Learning with errors problem of lattice,a multi-authorization policy attribute encryption scheme is proposed.In the scheme,the single-authorization center is extended to a central authority and a multi-attribute authority,and the system parameter generation and user attribute management are implemented respectively.The flexible linear secret sharing structure Linear Sharing Secret Scheme is selected for the access structure.Finally,the correctness of the scheme is deduced,and the security is analyzed.(2)For the problem of private key leakage of user attributes in the existing ciphertext strategy attribute encryption scheme.Based on the Learning with errors problem on the lattice,a cryptographic policy attribute encryption scheme with user traceability and support for Ordered Binary Decision Diagram access policy is constructed,and the user is tracked by the authentication information generated by qualified signature on user tracing.In the scheme,the ordered decision binary graph is selected as the user access policy structure to support the positive and negative values of the attributes.(3)For the problem of revocation of user partial attributes in the existing ciphertext policy attribute encryption scheme.Based on the Learning with errors problem in lattice,a scheme of user partial attribute revocation is proposed.The scheme uses binary key encryption tree to realize the management of user attribute group and the revocation of user partial attribute.The scheme uses ordered binary decision graph to represent user’s access policy.Finally,the scheme is derived and analyzed.