Received 26 January 2023, accepted 28 February 2023, date of publication 10 March 2023, date of current version 5 April 2023. Digital Object Identifier 10.1109/ACCESS.2023.3255779 Design and Implementation of a Configurable Encryption System for Power-Constrained Devices J. D. J. DE LA ROSA-DE LA ROSA 1,2 , J. S. MURGUÍA 2 , M. MEJÍA-CARLOS 1,2 , AND MIGUEL ÁNGEL LASTRAS-MONTAÑO 1,2 1 Instituto de Investigación en Comunicación Óptica, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78210, México 2 Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78295, México Corresponding authors: M. Mejía-Carlos (marcela.mejia@uaslp.mx) and Miguel Ángel Lastras-Montaño (miguel.lastras@uaslp.mx) This work was partially supported by the Consejo Nacional de Ciencia y Tecnología (CONACYT) under Grant CB2017-2018-A1-S- 45697. J. D. J. De La Rosa-De La Rosa was supported by a CONACYT Scholarship under Grant CVU 931148. The authors thankfully acknowledge the computer resources, technical expertise and support provided by the Laboratorio Nacional de Supercómputo del Sureste de México, CONACYT member of the network of national laboratories, under project 202201019N. ABSTRACT In this work, we present a configurable encryption system based on the Encryption by Synchronization in a Cellular Automata (ESCA) system, which is a symmetric key algorithm based on the synchronization phenomenon of Cellular Automata with rule-90. With the aim of producing a flexible system to trade-off power consumption and security level, we implemented a pseudo-random number generator (PRNG) that can be configured with three different key sizes. This variable-length PRNG, together with the capability of bypassing specific modules in the rest of the system, allow us to operate under a wide range of applications. In particular, it would enable online adjustments in IoT and power-constrained devices to fine- tune them between a low-power consumption and a maximum-security level. The system can be implemented with 5956 gates, and it is designed to provide in a 0.5 µm CMOS process a throughput of 50 Mbps @ 37 mW, at the maximum-security level, and an energy consumption of less than 7 mW @ 30 Mbps at the lowest- security level, while still providing a satisfactory perceptual security metric. INDEX TERMS Cipher, cellular automata, symmetric cryptosystem, CMOS, ASIC. I. INTRODUCTION Nowadays, embedded systems are used in a wide variety of applications such as wearable devices, medical implants, Internet of Things (IoT) devices, Radio-frequency identifi- cation (RFID) tags, and Wireless Sensor Networks (WSN). An important property of these systems is their capacity to securely store, access, and transmit information, and the process responsible for safeguarding this information does not have a low energy cost [1], [2]. To achieve this, different types of encryption systems have been developed to safeguard the confidentiality and integrity of information. A problem to overcome is that embedded systems are typically battery-operated, and the time and energy costs The associate editor coordinating the review of this manuscript and approving it for publication was Jun Wang . of using an encryption system are high [3], [4], [5]. Such energy-constrained embedded systems require a low-cost specialized encryption process with low energy consumption and a small footprint area [6], [7]. Instead of implementing these encryption systems in software or general purpose hardware (e.g. single-board computers, microcontrollers, or FPGAs), an Application-Specific Integrated Circuit (ASIC) approach is preferred. An encryption process is a tool to protect information, transforming the data into illegible text in such way that only the recipient is able to return to the original form of the information. Some of the most common encryption systems are AES [8], DES [9], and 3DES [10]. The main problem with the DES system is that, with the current computing power, it can be broken with using a brute force attack. To solve this problem, the 3DES system was implemented, which 32842 This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/ VOLUME 11, 2023