Research On Ciphertext Policy Attribute Based Encryption On Lattices

Compared with the traditional public-key encryption system,attribute-based encryption can not only ensure the confidentiality of data,but also realize one-to-many and many-to-many communication and provide flexible access control for ciphertext.These advantages make it very suitable for modern open network environments,and it has been widely studied by scholars.In the ciphertext policy attribute-based encryption scheme,the sender determines the access policy to achieve control over the receiving group,which makes the ciphertext policy attribute-based encryption scheme more suitable for dynamic scenarios such as mobile social network.With the development of quantum computers,the traditional cryptographic mechanism based on bilinear pairing cannot resist quantum attacks,but the cryptographic scheme on lattices is considered to be able to resist quantum attacks.At the same time,the cryptographic scheme on lattices has the advantages of high computational efficiency,so the ciphertext policy attribute-based encryption on lattices has higher research value.This paper focuses on the topic of encryption mechanism based on the ciphertext policy attribute-based encryption on lattice.Starting from the existing research hotspots,the following work is mainly done:(1)To solve the problem of attribute revocation in the ciphertext policy attribute-based encryption on lattices under the data outsourcing environment,we designs a revocable ciphertext policy attribute-based encryption scheme under the outsourcing environment.The scheme uses the LWE problem to construct the encryption and decryption algorithm,and the data outsourcing management server is used to realize the attribute revocation.The analysis shows that the scheme has a reduced key length,flexible access policy,support for fine-grained attribute revocation,real-time revocation of attributes,and resistance to quantum attacks.(2)Aiming at the problem of access structure design in the ciphertext policy attribute-based encryption on lattices,the access tree is introduced into the ciphertext policy attribute-based encryption on lattices.Based on the ideal lattice R-LWE problem,we proposed a ciphertext policy attribute-based encryption scheme supporting tree-access structure on ideal lattices that restricts user access to ciphertext through the access tree in the ciphertext.The scheme has the advantages of smaller key size and higher encryption efficiency.(3)Considering that attribute revocation in the attribute-based encryption is the key problem,we design a revocable ciphertext policy attribute-based encryption scheme on ideal lattices.The idea of version number is used to implement attribute revocation.The ciphertext is re-encrypted by the proxy server to complete the attribute revocation.The correctness,security and performance of the scheme are analyzed.