Lattice CP-ABE Scheme Supporting Reduced-OBDD Structure

Ciphertext attribute-based encryption (CP-ABE) schemes from lattices are considered as a flexible way of ensuring access control, which allow publishers to encrypt data for many users without worrying about quantum attacks and exponential computational inefficiencies. However, most of the proposed schemes are inefficient, inflexible, and cannot support flexible expression of access policy. To achieve an efficient and flexible access policy expression, we construct CP-ABE scheme from lattice which supports reduced ordered binary decision diagram (reduced-OBDD) structure. This approach is entirely different but can achieve an efficient and flexible access policy. Encryption and decryption are based on walking on the links between the nodes instead of using the nodes. By adopting the strategy of using Reduced-OBDD and walking on its links, we can obtain an optimized access structure for our policy which do not only support AND, OR, and Threshold operations but also support negative and positive attributes. We finally prove our scheme to be secured under decision R-Learning with error problem in a selective set model.