  Narrowband Internet of Things (NB-IoT) is a wireless communication technology
that enables a wide range of applications, from smart cities to industrial
automation. As a part of the 5G extension, NB-IoT promises to connect billions
of devices with low-power and low-cost requirements. However, with the advent
of quantum computers, the incoming NB-IoT era is already under threat by these
devices, which might break the conventional cryptographic algorithms that can
be adapted to secure NB-IoT devices on large scale. In this context, we
investigate the feasibility of using post-quantum key exchange and signature
algorithms for securing NB-IoT applications. We develop a realistic ns-3
environment to represent the characteristics of NB-IoT networks and analyze the
usage of post-quantum algorithms to secure communication. Our findings suggest
that using NIST-selected post-quantum key-exchange protocol Kyber does not
introduce significant overhead, but post-quantum signature schemes can result
in impractical latency times and lower throughputs
