Efficient ring signature schemes over NTRU Lattices.

Two ring signature schemes over number theory research unit (NTRU) lattices are presented. The first scheme constructed in the random oracle model is an extension of Ducas, Lyubashevsky, and Prest's identity-based encryption scheme over NTRU lattices (in Asiacrypt 2014). Moreover, motivated by Boyen's lattice mixing and vanishing trapdoors (in PKC 2010), the second scheme in the standard model is achieved. Under the chosen-message attack, our new constructions are proved strongly existentially unforgeable, and the security can be reduced to the hardness of NTRU lattices. Compared with the existing lattice-based ring signatures, our schemes are more efficient and with shorter signature length. Copyright (c) 2016 John Wiley & Sons, Ltd.