More efficient CCA-secure unidirectional proxy re-encryption schemes without random oracles

In this paper, we present a more efficient chosen-ciphertext secure proxy re-encryption scheme in the standard model with less ciphertext size and without any strong unforgeable one-time signature. Our scheme is unidirectional and single-hop. The security of our scheme is under the reasonable complexity assumption-the decisional bilinear Diffie-Hellman assumption in bilinear groups. There are no proxy re-encryption schemes achieving chosen-ciphertext security in the standard model without a strong unforgeable one-time signature in the literature.