A provably secure collusion-resistant identity-based proxy re-encryption scheme based on NTRU

Proxy re-encryption (PRE) technology realizes the transformation of decryption right from a delegator to a delegatee. In response to the rapid development of quantum attack technology, scholars have proposed the lattice-based PRE schemes, and the underlying encryption scheme of most lattice-based PRE schemes is the dual cryptosystem, which has the defects of large storage overhead, computational overhead and low efficiency. To address these deficiencies, we present a novel identity-based proxy re-encryption (IB-PRE) scheme based on NTRU. By means of the underlying efficient NTRU scheme, the proposed scheme reduces the storage overhead and computational overhead on key size and computational complexity, and improves efficiency. Our scheme possesses desired properties such as multi-hop property, unidirectionality and collusion-resistance. Meanwhile, based on the decisional Hermite normal form of ring learning with errors (D-RLWEHNF) hard problem, it is carefully designed and demonstrated to be secure under selective identity and chosen plaintext attacks in the standard model.