Research On Attribute-Based Encryption From Lattices

As an effective means of encrypting data,attribute-based encryption(ABE)can achieve fine-grained access control of ciphertext data by users,and it controls users' decryption operations through access strategy.At the same time,cryptographic schemes from lattices have the advantages of resisting quantum computation attacks,running efficiently and being easy to implement.Therefore,the construction of ABE from lattices is a research hotspot in cryptography.However,most attribute-based encryption schemes from lattices can't support attribute revocation,and their private key generation centers have too much computational overheads.This thesis studies the two problems and puts forward corresponding solutions.To solve the problem of attribute revocation on lattices,this thesis proposes an attribute-based encryption scheme with efficient revocation from lattices.Compared with other ABE schemes from lattices,the proposed scheme of this thesis designs a new attribute revocation structure,which makes the time complexity of revocation logarithmic with the number of user's attributes,and improves the efficiency of attribute revocation.At the same time,the scheme supports threshold access control and achieves a more flexible access strategy.Finally,the security of the scheme is proved in the standard model.To solve substantial computational overheads of private key generation center,this thesis proposes an outsourcing revocable and authorizable attribute-based encryption scheme from lattices.In most ABE schemes that support revocation,the operation of revoking attributes is performed by private key generation center,which requires frequent updates of attribute keys that have not been revoked.The proposed scheme delegates the attribute revocation operation to the outsourced cloud server,the feasibility of the scheme is verified by the description of the scheme and correctness analysis.At the same time,the scheme supports and,or and threshold access control,which enhances the flexibility of access control.Finally,the performance evaluation shows that the proposed scheme has more advantages in computational overheads.