Cryptanalysis of Wang et al.’s lattice-based key exchange protocol

Abstract

Summary Wang et al. proposed a new hard problem on lattices which is an extension of the small integer solution (SIS) on lattices. This new generated hard problem is named to be bilateral in-homogeneous small integer solution (Bi-ISIS). Using the hardness of Bi-ISIS, Wang et al. proposed a new key exchange protocol, which is based on the lattice-based cryptography. In this paper, we signalize that Wang et al.’s lattice-based key exchange protocol is vulnerable to an attack, namely, man-in-the-middle (MITM) attack. Through this attack, Eavesdropper can intercept the authenticated messages and communicate the unauthentic messages among the communicating parties.