A Novel Lattice-Based Ciphertext-Policy Attribute-Based Proxy Re-encryption for Cloud Sharing

Proxy re-encryption plays an important role in cloud sharing. Ciphertext-policy attribute-based proxy re-encryption (CP-ABPRE) scheme supports access control and can convert the ciphertext under an access policy to a ciphertext under another access policy, which is flexible and efficient for cloud sharing. The existing CP-ABPRE schemes are constructed by bilinear pairing or multi-linear maps which are fragile when the post-quantum comes. In this paper, a unidirectional single-hop CP-ABPRE scheme with small size of public parameters was presented by using trapdoor sampling, and proved secure under learning with errors assumption which is widely believed secure in quantum computer attacks.