## 1 Introduction  
With the advances of information technology (IT) applications involving sensitive data, the network security is an ever-current topic for business activities; therefore, the development of robust, in computational terms light and efficient encryption algorithms is required for supporting the continuous increase of data volume and throughput in IoT applications, as well as video streaming, real-time communications, mobile transmissions and so forth [1; 2; 3; 4]. The Advanced Encryption Standard (AES) remains the preferred encryption standard for governments, banks and high-security systems around the world. This last is the most widespread encryption algorithm, for instance,employed in Gigabit Ethernet, Worldwide Interoperability for Microwave Access (WiMAX) and 5G systems [5; 6; 7]. Also, this algorithm can be efficiently implemented both in hardware and software platforms; the software implementations of AES require lower resources but offer lower physical security. On the other hand, the growing demand for high-speed, high-volume secure data transmissions, ensuring at the same time the physical security, strongly requires the hardware implementation of the AES algorithm [8; 9; 10]. The Field Programmable Gate Array (FPGA) represents the ideal platform for implementing the ciphering algorithm to ensure the network security; however, the implementation of high throughput encryption/decryption algorithm is a challenge, given the limited resources of the considered platform; therefore, the development of resource-efficient AES encryptor/decryptor on the FPGA platform is crucial, as described above. The (Inv)SubBytes (Sbox) phase significantly affects the performance of the whole encryption algorithm; therefore several approaches are developed for reducing the computational load and resource, such as Composite Field Arithmetic (CFA) and look-up table (LUT) methods [1]. The communication networks are usually arranged into four sections, namely radio access network (RAN), core network, transport network and interconnection network; concerning the network security, the supported network planes (signal, user and management ones) are exposed to different threat typologies. Specifically, the network threats are classified in passive network threats and active network ones; the first ones are aimed to intercept the traffic sent on the network, whereas the second type includes all the attacks in which the execution of commands is involved to disturb the communication. The introduction of the 5G technology signs the beginning of new concepts also in terms of network security, such as the International Mobile Subscriber Identity (IMSI) encryption while it is transmitted through the network, protecting it from external attacks. Furthermore, the 5G enables the extension of security mechanisms employed in the cellular networks to other wireless networks, ensuring the protection of the smart devices and stored data, a concept called \"home network control.\" In this contest, the standardization is fundamental in order to guarantee full compatibility with the different networks present around the globe. As well known, the most widespread encryption algorithms for 5G and in general, for high throughput applications, are the AES, SNOW 3G and ZUC ones [11; 12]; the AES algorithm is very robust against multiple attacks, such as the brute-force, linear and differential ones. However, the AES algorithm requires hardware acceleration methods to reduce the execution time in the downlink, keeping low the area and energy requirements for mobile devices. On the other hand, the SNOW 3G, updated into a faster version called SNOW-V, complies with all the requirements of 5G, ensuring security, performance and flexibility.