{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T01:23:14Z","timestamp":1777339394842,"version":"3.51.4"},"reference-count":21,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2023,8,24]],"date-time":"2023-08-24T00:00:00Z","timestamp":1692835200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"MSIT (Ministry of Science and ICT), Korea, under the ITRC support program","award":["IITP-2021-0-02052"],"award-info":[{"award-number":["IITP-2021-0-02052"]}]},{"name":"MSIT (Ministry of Science and ICT), Korea, under the ITRC support program","award":["2021R1A2C1011232"],"award-info":[{"award-number":["2021R1A2C1011232"]}]},{"name":"MSIT (Ministry of Science and ICT), Korea, under the ITRC support program","award":["20210007790012003"],"award-info":[{"award-number":["20210007790012003"]}]},{"name":"National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT)","award":["IITP-2021-0-02052"],"award-info":[{"award-number":["IITP-2021-0-02052"]}]},{"name":"National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT)","award":["2021R1A2C1011232"],"award-info":[{"award-number":["2021R1A2C1011232"]}]},{"name":"National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT)","award":["20210007790012003"],"award-info":[{"award-number":["20210007790012003"]}]},{"name":"Korean Government (MSIT)","award":["IITP-2021-0-02052"],"award-info":[{"award-number":["IITP-2021-0-02052"]}]},{"name":"Korean Government (MSIT)","award":["2021R1A2C1011232"],"award-info":[{"award-number":["2021R1A2C1011232"]}]},{"name":"Korean Government (MSIT)","award":["20210007790012003"],"award-info":[{"award-number":["20210007790012003"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>With the increasing number of edge devices connecting to the cloud for storage and analysis, concerns about security and data privacy have become more prominent. Homomorphic encryption (HE) provides a promising solution by not only preserving data privacy but also enabling meaningful computations on encrypted data; while considerable efforts have been devoted to accelerating expensive homomorphic evaluation in the cloud, little attention has been paid to optimizing encryption and decryption (ENC-DEC) operations on the edge. In this paper, we propose efficient hardware architectures for CKKS-based ENC-DEC accelerators to facilitate computations on the client side. The proposed architectures are configurable to support a wide range of polynomial sizes with multiplicative depths (up to 30 levels) at a 128-bit security guarantee. We evaluate the hardware designs on the Xilinx XCU250 FPGA platform and achieve an average encryption time 23.7\u00d7 faster than that of the well-known SEAL HE library. By reducing time complexity and improving the hardware utilization of cryptographic algorithms, our configurable CKKS-supported ENC-DEC hardware designs have the potential to greatly accelerate cryptographic processes on the client side in the post-quantum era.<\/jats:p>","DOI":"10.3390\/s23177389","type":"journal-article","created":{"date-parts":[[2023,8,24]],"date-time":"2023-08-24T10:47:08Z","timestamp":1692874028000},"page":"7389","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["Configurable Encryption and Decryption Architectures for CKKS-Based Homomorphic Encryption"],"prefix":"10.3390","volume":"23","author":[{"given":"Jaehyeok","family":"Lee","sequence":"first","affiliation":[{"name":"Department of Electrical and Computer Engineering, Inha University, Incheon 22212, Republic of Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0311-9387","authenticated-orcid":false,"given":"Phap Ngoc","family":"Duong","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Inha University, Incheon 22212, Republic of Korea"},{"name":"Faculty of Computer Engineering and Electronics, The University of Danang\u2013Vietnam-Korea University of Information and Communication Technology, Danang 50000, Vietnam"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8815-1927","authenticated-orcid":false,"given":"Hanho","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Inha University, Incheon 22212, Republic of Korea"}]}],"member":"1968","published-online":{"date-parts":[[2023,8,24]]},"reference":[{"key":"ref_1","first-page":"169","article-title":"On data banks and privacy homomorphisms","volume":"4","author":"Rivest","year":"1978","journal-title":"Found. Comput. Decis. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1145\/2535925","article-title":"On ideal lattices and learning with errors over rings","volume":"60","author":"Lyubashevsky","year":"2013","journal-title":"J. ACM"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"760","DOI":"10.1109\/TPDS.2020.3030748","article-title":"Homomorphic sorting with better scalability","volume":"32","author":"Sunar","year":"2021","journal-title":"IEEE Trans. Parallel Distrib. Syst."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Cheon, J.H., Han, K., Kim, A., Kim, M., and Song, Y. (2018, January 15\u201317). A full RNS variant of approximate homomorphic encryption. Proceedings of the Selected Areas in Cryptography\u2013SAC 2018: 25th International Conference, Calgary, AB, Canada.","DOI":"10.1007\/978-3-030-10970-7_16"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"353","DOI":"10.1109\/TVLSI.2019.2943127","article-title":"Design and implementation of encryption\/decryption architectures for BFV homomorphic encryption scheme","volume":"28","author":"Mert","year":"2019","journal-title":"IEEE Trans. Very Large Scale Integr."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"756","DOI":"10.46586\/tches.v2021.i3.756-779","article-title":"Seal-embedded: A homomorphic encryption library for the internet of things","volume":"9","author":"Natarajan","year":"2021","journal-title":"IACR Trans. Cryptogr. Hardw. Embed. Syst."},{"key":"ref_7","unstructured":"van der Hagen, M., and Lucia, B. (March, January 28). Client-optimized algorithms and acceleration for encrypted compute offloading. Proceedings of the 27th ACM International Conference on Architectural Support for Programming Languages and Operating Systems, Lausanne, Switzerland."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Azad, Z., Yang, G., Agrawal, R., Petrisko, D., Taylor, M., and Joshi, A. (2022, January 1\u20133). RACE: RISC-V SoC for En\/Decryption Acceleration on the Edge for Homomorphic Computation. Proceedings of the ACM\/IEEE International Symposium on Low Power Electronics and Design, Boston, MA, USA.","DOI":"10.1145\/3531437.3539725"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Nguyen, T.T., Kim, J., and Lee, H. (2023, January 21\u201325). CKKS-Based Homomorphic Encryption Architecture using Parallel NTT Multiplier. Proceedings of the 2023 IEEE International Symposium on Circuits and Systems (ISCAS), Monterey, CA, USA.","DOI":"10.1109\/ISCAS46773.2023.10181714"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Cheon, J.H., Kim, A., Kim, M., and Song, Y. (2017, January 3\u20137). Homomorphic Encryption for Arithmetic of Approximate Numbers. Proceedings of the Advances in Cryptology\u2013ASIACRYPT 2017: 23rd International Conference on the Theory and Applications of Cryptology and Information Security, Hong Kong, China.","DOI":"10.1007\/978-3-319-70694-8_15"},{"key":"ref_11","unstructured":"Crandall, R., and Pomerance, C. (2005). Prime Numbers: A Computational Perspective, Springer. [2nd ed.]."},{"key":"ref_12","first-page":"1","article-title":"Somewhat practical fully homomorphic encryption","volume":"144","author":"Fan","year":"2012","journal-title":"IACR Cryptol. Eprint Arch."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Brakerski, Z. (2012, January 19\u201323). Fully homomorphic encryption without modulus switching from classical GapSVP. Proceedings of the Advances in Cryptology\u2013CRYPTO 2012: 32nd Annual Cryptology Conference, Santa Barbara, CA, USA.","DOI":"10.1007\/978-3-642-32009-5_50"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1145\/2633600","article-title":"(Leveled) fully homomorphic encryption without bootstrapping","volume":"6","author":"Brakerski","year":"2014","journal-title":"ACM Trans. Comput. Theory"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1270","DOI":"10.1109\/TCSI.2022.3225208","article-title":"Area-efficient number-theoretical transform architecture for Homomorphic encryption","volume":"70","author":"Kwon","year":"2023","journal-title":"IEEE Trans. Circuits Syst. I Regul. Pap."},{"key":"ref_16","unstructured":"(2023, February 14). Microsoft SEAL (Release 4.0). Available online: https:\/\/github.com\/Microsoft\/SEAL."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Lauter, K., Dai, W., and Laine, K. (2022). Protecting Privacy through Homomorphic Encryption, Springer.","DOI":"10.1007\/978-3-030-77287-1"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Duong, P.N., and Lee, H. (2023). Pipelined Key Switching Accelerator Architecture for CKKS-Based Fully Homomorphic Encryption. Sensors, 23.","DOI":"10.3390\/s23104594"},{"key":"ref_19","first-page":"4068","article-title":"PipeNTT: A Pipelined Number Theoretic Transform Architecture","volume":"69","author":"Ye","year":"2022","journal-title":"IEEE Trans. Circuits Syst. II Express Briefs"},{"key":"ref_20","unstructured":"Hirner, F., Mert, A.C., and Roy, S.S. (2023). PROTEUS: A Tool to generate pipelined Number Theoretic Transform Architectures for FHE and ZKP applications. Cryptol. ePrint Arch., Available online: https:\/\/eprint.iacr.org\/2023\/267."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Kurniawan, S., Duong-Ngoc, P., and Lee, H. (2023). Configurable Memory-Based NTT Architecture for Homomorphic Encryption. IEEE Trans. Circuits Syst. II Express Briefs.","DOI":"10.1109\/TCSII.2023.3289489"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/17\/7389\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T20:38:19Z","timestamp":1760128699000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/17\/7389"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,8,24]]},"references-count":21,"journal-issue":{"issue":"17","published-online":{"date-parts":[[2023,9]]}},"alternative-id":["s23177389"],"URL":"https:\/\/doi.org\/10.3390\/s23177389","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,8,24]]}}}