{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:28:46Z","timestamp":1760232526928,"version":"build-2065373602"},"reference-count":27,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2022,11,10]],"date-time":"2022-11-10T00:00:00Z","timestamp":1668038400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Institute for Information &amp; communications Technology Promotion (IITP)","award":["2018-0-00264","2022-0-00627"],"award-info":[{"award-number":["2018-0-00264","2022-0-00627"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>Internet of Things (IoT) technology, in which numerous devices cooperate, has a significant impact on existing industries, such as smart factories, smart cars, and smart cities. Massive learning and computing using data collected through the IoT are also being actively performed in these industries. Therefore, the security of low-end microcontrollers used in the Internet of Things should be highly considered due to their importance. Simpira Permutation is a Permutation design using the AES algorithm designed to run efficiently on 64-bit high-end processors. With the efficient implementation of Simpira algorithm, we can ensure secure massive learning in IoT devices without performance bottleneck. In nature, Simpira exploited the part of AES algorithm. The AES algorithm is the most widely used in the world, and Intel has developed hardware accelerated AES instruction set (AES-NI) to improve the performance of encryption. By using AES-NI modules, Simpira can be improved further on high-end devices. On the other hand, low-end processors do not support AES-NI modules. For this reason, an optimized implementation of efficient Simpira should be considered. In this paper, we present an optimized implementation of Simpira on 8-bit AVR microcontrollers and 32-bit RISC-V processors, which are low-end processors that do not support AES-NI features. There are three new techniques applied. First, Addroundkey is computed efficiently through pre-computation. Second, it takes advantage of the characteristics of round keys to omit some of the operations. Third, we omit unnecessary operations added to use AES-NI features.\u00a0We have carried out performance evaluations on 8-bit ATmega128 microcontrollers and 32-bit RISC-V processors, which show up-to 5.76\u00d7 and 37.01\u00d7 better performance enhancements than the-state-of-art reference C codes for the Simpira, respectively.<\/jats:p>","DOI":"10.3390\/sym14112377","type":"journal-article","created":{"date-parts":[[2022,11,10]],"date-time":"2022-11-10T19:18:29Z","timestamp":1668107909000},"page":"2377","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Optimized Implementation of Simpira on Microcontrollers for Secure Massive Learning"],"prefix":"10.3390","volume":"14","author":[{"given":"Minjoo","family":"Sim","sequence":"first","affiliation":[{"name":"Division of IT Convergence Engineering, Hansung University, Seoul 02876, Korea"}]},{"given":"Siwoo","family":"Eum","sequence":"additional","affiliation":[{"name":"Division of IT Convergence Engineering, Hansung University, Seoul 02876, Korea"}]},{"given":"Hyeokdong","family":"Kwon","sequence":"additional","affiliation":[{"name":"Division of IT Convergence Engineering, Hansung University, Seoul 02876, Korea"}]},{"given":"Kyungbae","family":"Jang","sequence":"additional","affiliation":[{"name":"Division of IT Convergence Engineering, Hansung University, Seoul 02876, Korea"}]},{"given":"Hyunjun","family":"Kim","sequence":"additional","affiliation":[{"name":"Division of IT Convergence Engineering, Hansung University, Seoul 02876, Korea"}]},{"given":"Hyunji","family":"Kim","sequence":"additional","affiliation":[{"name":"Division of IT Convergence Engineering, Hansung University, Seoul 02876, Korea"}]},{"given":"Gyeongju","family":"Song","sequence":"additional","affiliation":[{"name":"Division of IT Convergence Engineering, Hansung University, Seoul 02876, Korea"}]},{"given":"Waikong","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Computer Engineering, Gachon University, Seongnam 13306, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0069-9061","authenticated-orcid":false,"given":"Hwajeong","family":"Seo","sequence":"additional","affiliation":[{"name":"Division of IT Convergence Engineering, Hansung University, Seoul 02876, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2635","DOI":"10.1109\/JIOT.2020.3019707","article-title":"Multilayer internet-of-things middleware based on knowledge graph","volume":"8","author":"Xie","year":"2020","journal-title":"IEEE Internet Things J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1186\/s13634-022-00867-2","article-title":"Analytical offloading design for mobile edge computing-based smart internet of vehicle","volume":"2022","author":"Lu","year":"2022","journal-title":"EURASIP J. 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