Lattice Ciphertext-Policy Attribute-Based encryption from ring-LWE

The recent promising results on the hardness of lattice problems have inspired the construction of several Attribute-based Encryption (ABE) schemes from the quantum resistant perspective. However, these schemes are insufficient enough for supporting real-world applications due to inherent quadratic overhead problem in the use of Learning With Error (LWE). To solve this problem, this paper proposed a Ciphertext-Policy Attribute-Based Encryption (CP-ABE) scheme from a more lightweight ideal lattice classes- Ring-Learning with Errors (Ring-LWE), that further called as CP-ABE_R-LWE scheme. Compared to existing R-LWE based ABE scheme, the proposed CP-ABE_R-LWE is capable to handle a monotone access structure and enjoys collusion resistance properties. We exploited Linear Secret Scheme (LSSS) to express a monotone access structure. For resist to collusion attack, we applied the private key randomization technique to blind the user´s private key. The proposed scheme CP-ABE_R-LWE is further proven to be secure under the Decision Ring-LWE_d,q,χ problem in the selective set model.