# Evaluating the Efficiency of Physical and Cryptographic Security Solutions for Quantum Immune IoT
## 1 Introduction  
Quantum computers will revolutionize the cryptanalysis field as they can easily solve [1; 2; 3] foundational problems that modern cryptographic algorithms have relied on. Quantum computers can be used to break asymmetric cryptography and, thus, make it possible to eavesdrop and tamper most communication that is protected with modern security protocols. This threat of quantum computers forces us to replace the vulnerable algorithms used for securing communication and data in billions of devices. Hence, the security field is currently searching for authentication and confidentiality solutions that provide immunity against quantum computers and that are feasible for all kinds of devices including energy-restricted and Internet of Things (IoT) devices. Standards for quantum immune cryptography are currently being developed through an open competition [4]. Quantum immune cryptographic algorithms for encryption, key exchange, authentication and digital signing are based on problems that are assumed to be resistant to quantum computing as well as classical cryptanalysis. Recent lattice-based proposals for key exchange, such as NewHope [5] and Frodo [6], have also been considered computationally feasible. However, in addition to cryptography, there are other security alternatives providing quantum immunity, including the quantum-keydistribution for optics (see, e.g., [7; 8]) and secrecy coding for wireless communications, which is our focus in this article. Physical layer security is a new research field [9; 10] that utilizes the physical properties of radio communication channels to make eavesdropping very difficult. Physical layer security can be generally divided into two categories: secrecy coding methods that secretly convey information using the properties of the wireless medium, and extraction methods that seek to build secret information by adopting the inherent randomness of wireless channels. Roughly speaking, in secrecy coding methods, it is possible to communicate secretly if one can devise a way to ensure that the wireless channel between the legitimate transmitter and receiver is better than the channel of any illegitimate receiver. For example, the transmitter can generate a special jamming signal that affects all but the the legitimate receiver [11]. Then, in theory, the channel between the legitimate parties has a higher capacity than an eavesdroppers' channel, and the eavesdroppers get less information than the legitimate receiver. The information that the eavesdroppers do not get is a shared secret. Extraction methods, on the other hand, seek to use the unique space, time, and frequency characteristics of the wireless channel as the source of shared secret information between a transmitter and a receiver. Consequently, physical layer security methods could be used to exchange a shared secret and thus complement quantum immune security systems, e.g., by providing a (quantum immune) confidentiality property for the key exchange system. The research related to the post-quantum security field has so far focused on the hardness and security level of algorithms. Feasibility of the proposals has been validated by analysing the computational complexity of the algorithms and by evaluating the implementations experimentally (see e.g., [6; 12; 13; 14; 15; 16; 17; 18]). In this paper, we propose a simulation-based approach--based on the ABSOLUT tool [19]--for evaluating the energy efficiency of security algorithms. The simulation-based approach allows us to study easily the energy and power consumption of algorithms on different hardware platforms. With the ABSOLUT tool, we can more easily study how changes in algorithm or hardware design will affect energy consumption. The contributions of this paper are concluded as follows:  
* We present an implementation of a secrecy coding scheme from [20] that provides resistance against eavesdropping and, thus, quantum immunity.