{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,24]],"date-time":"2025-10-24T21:07:48Z","timestamp":1761340068907},"reference-count":12,"publisher":"World Scientific Pub Co Pte Lt","issue":"02","funder":[{"name":"National Research Foundation of Kore","award":["NRF-2018R1A2A1A05079095"],"award-info":[{"award-number":["NRF-2018R1A2A1A05079095"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Int. J. Found. Comput. Sci."],"published-print":{"date-parts":[[2020,2]]},"abstract":"<jats:p> Multikey fully homomorphic encryption (MFHE) allows homomorphic operations between ciphertexts encrypted under different keys. In applications for secure multiparty computation (MPC) protocols, MFHE can be more advantageous than usual fully homomorphic encryption (FHE) since users do not need to agree with a common public key before the computation when using MFHE. In EUROCRYPT 2016, Mukherjee and Wichs constructed a secure MPC protocol in only two rounds via MFHE which deals with a common random\/reference string (CRS) in key generation. After then, Brakerski et al. replaced the role of CRS with the distributed setup for CRS calculation to form a four round secure MPC protocol. Thus, recent improvements in round complexity of MPC protocols have been made using MFHE. <\/jats:p><jats:p> In this paper, we go further to obtain round-efficient and secure MPC protocols. The underlying MFHE schemes in previous works still involve the common value, CRS, it seems to weaken the power of using MFHE to allow users to independently generate their own keys. Therefore, we resolve the issue by constructing an MFHE scheme without CRS based on LWE assumption, and then we obtain a secure MPC protocol against semi-malicious security in three rounds. We also define a new security notion \u201cmultikey-CPA security\u201d to prove that a multikey ciphertext cannot be decrypted unless all the secret keys are gathered and our scheme is multikey-CPA secure. <\/jats:p>","DOI":"10.1142\/s012905412050001x","type":"journal-article","created":{"date-parts":[[2020,3,9]],"date-time":"2020-03-09T09:17:18Z","timestamp":1583745438000},"page":"157-174","source":"Crossref","is-referenced-by-count":11,"title":["Towards Round-Optimal Secure Multiparty Computations: Multikey FHE Without a CRS"],"prefix":"10.1142","volume":"31","author":[{"given":"Eunkyung","family":"Kim","sequence":"first","affiliation":[{"name":"Security Research Team, Samsung SDS, E tower, Seongchongil 56, Seocho-gu, Seoul, 06765, Republic of Korea"}]},{"given":"Hyang-Sook","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Mathematics, Ewha Womans University, Ewhayeodaegil 52, Seodaemun-gu, Seoul, 03760, Republic of Korea"}]},{"given":"Jeongeun","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Mathematics, Ewha Womans University, Ewhayeodaegil 52, Seodaemun-gu, Seoul, 03760, Republic of Korea"}]}],"member":"219","published-online":{"date-parts":[[2020,3,6]]},"reference":[{"key":"S012905412050001XBIB001","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-642-29011-4_29"},{"key":"S012905412050001XBIB003","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-70500-2_22"},{"key":"S012905412050001XBIB004","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-662-48000-7_31"},{"key":"S012905412050001XBIB005","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-78375-8_16"},{"key":"S012905412050001XBIB007","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-642-40041-4_5"},{"key":"S012905412050001XBIB008","series-title":"ACM","volume-title":"Proceedings of the Nineteenth Annual ACM Symposium on Theory of Computing","author":"Goldreich O."},{"key":"S012905412050001XBIB009","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-93638-3_7"},{"key":"S012905412050001XBIB010","doi-asserted-by":"publisher","DOI":"10.1145\/2213977.2214086"},{"key":"S012905412050001XBIB011","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-642-29011-4_41"},{"key":"S012905412050001XBIB012","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-662-49896-5_26"},{"key":"S012905412050001XBIB013","doi-asserted-by":"publisher","DOI":"10.1145\/1568318.1568324"},{"key":"S012905412050001XBIB014","first-page":"160","volume-title":"23rd Annual Symposium on Foundations of Computer Science","author":"Yao A. 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