Identity-based proxy signature over NTRU lattice

Proxy signature scheme is an important cryptographic primitive, for an entity can delegate his signing right to another entity. Although identity-based proxy signature schemes based on conventional number-theoretic problems have been proposed for a long time, the researchers have paid less attention to lattice-based proxy signature schemes that can resist quantum attack. In this paper, we first propose an identity-based proxy signature scheme over Number Theory Research Unit (NTRU)-lattice. We proved that the proposed paradigm is secure under the hardness of the γ-shortest vector problem on the NTRU lattice in random oracle model; furthermore, the comparison with some existing schemes shows our scheme is more efficient in terms of proxy signature secret key size, proxy signature size, and computation complexity. As the elemental problem of the proposed scheme is difficult even for quantum computation model, our scheme can work well in quantum age.