# Secure and Scalable Internet of Things Model Using Post-Quantum MACsec
## 1 Introduction  
IoT devices have become ubiquitous due to advances in seamless communication, wireless sensors, radio frequency identification (RFID), and cloud computing [1, 2]. The application of these devices has led to tremendous expansion that has even extended into our daily lives, including mobile devices, medical devices, wearable devices, home appliances, automotive devices, and industrial equipment [3, 4, 5, 6]. Moreover, the growth of smart devices has been significant in the automotive, healthcare, and retail fields [7]. The most critical feature of these devices is their ability to connect with humans, other devices, and systems without environmental constraints via an IoT network. As IoT architecture evolved from a closed and centralized network to a distributed cloud over the Internet, the network architecture of these devices has been proposed to mitigate IoT security threats while minimizing the security function load on embedded devices [8]. However, these proposed models do not concurrently offer many-to-many and end-to-end encryption and network separation from client to server. A Secure and Scalable IoT (SSI) network platform has been developed to handle security risks while managing the computing resources used by the IoT devices [9]. The SSI provides a layer 2 VPN,which incurs a lower load compared to the TCP/IP-based VPNs and offers data link frame encryption. It combines L2 TP and VXLAN for scalable layer 2 VPN, with the MACsec algorithm. However, a distinct public key encryption method for MACsec encrypted communication is not delineated. Quantum computers and quantum information science exploit nature's fundamental properties to facilitate a fundamentally different computation paradigm [10]. The primary distinction between a classical and quantum computer lies in the basic unit of information--the \"bit\". Unlike a classical bit, which can exist in one of two states (0 or 1), a \"qubit\" (quantum bit) can exist in both states simultaneously, a principle known as superposition and a cornerstone of quantum theory. The field of quantum algorithm development has experienced significant progress and innovation in recent years [11]. The key quantum algorithms developed include \"[PERSON]'s algorithm\", \"[PERSON]'s algorithm\", the \"Quantum Approximate Optimization Algorithm (QAOA)\", and the \"Harrow-Hassidim-Lloyd (HHL) algorithm\". Significantly, [PERSON]'s algorithm poses a major threat to public-key cryptosystems due to its ability to solve the prime factorization problem [12]. The RSA-2048, a leading public-key cryptosystem, is vulnerable with the availability of 4000 qubits [13]. Since quantum computing can potentially break traditional cryptographic algorithms, post-quantum cryptography (PQC) is required to ensure security against any attack by a quantum computer. PQC aims to provide the necessary security measures that remain robust in the era of quantum computing. Among the several types of PQC algorithms, Nth Degree Truncated Polynomial Ring Units (NTRUs) are notable for their minimal computing resource consumption and swift encryption/decryption processes [14]. However, NTRUs typically require a longer duration for encryption and decryption compared to RSA and ECC, necessitating a comprehensive evaluation of their application in IoT devices [15]. Thus, it is not advisable to simply apply NTRUs to the IoT network architecture due to their above-mentioned drawbacks. This paper introduces Post-Quantum MACsec-based SSI (SSI-PQM), which implements PQC in an IoT network platform by integrating NTRUs with SSI. It also employs MACsec for Layer 2 encryption communication. This study contributes to the literature by proposing an IoT network platform that efficiently provides post-quantum cryptography (PQC) in environments with low computing-power IoT devices and by validating the appropriate encryption level through experiments.