{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T13:24:06Z","timestamp":1765459446223,"version":"3.46.0"},"reference-count":22,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2025,12,10]],"date-time":"2025-12-10T00:00:00Z","timestamp":1765324800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100010712","name":"Vietnam National University HoChiMinh City","doi-asserted-by":"publisher","award":["DS.C2025-26-20"],"award-info":[{"award-number":["DS.C2025-26-20"]}],"id":[{"id":"10.13039\/501100010712","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cryptography"],"abstract":"<jats:p>Recent work at SCN 2020 by Boyen, Izabach\u00e8ne, and Li introduced a lattice-based key-encapsulation mechanism (KEM) that achieves CCA2-security in the standard model without relying on generic transformations. Their proof, however, leaves a few gaps that prevent a fully rigorous security justification. Building on the same design rationale, we revisit that construction and refine it to obtain a more compact and provably secure KEM under the Learning With Errors assumption. Furthermore, we extend this framework to derive an identity-based variant (IBKEM) whose security is established in the same model. The resulting schemes combine conceptual simplicity with improved efficiency and complete proofs of adaptive-ciphertext security.<\/jats:p>","DOI":"10.3390\/cryptography9040079","type":"journal-article","created":{"date-parts":[[2025,12,10]],"date-time":"2025-12-10T16:11:18Z","timestamp":1765383078000},"page":"79","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Efficient CCA2-Secure IBKEM from Lattices in the Standard Model"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9177-4719","authenticated-orcid":false,"given":"Ngoc Ai Van","family":"Nguyen","sequence":"first","affiliation":[{"name":"Department of Mathematics and Physics, University of Information Technology, Vietnam National University, Ho Chi Minh City 720325, Vietnam"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8057-4060","authenticated-orcid":false,"given":"Dung Hoang","family":"Duong","sequence":"additional","affiliation":[{"name":"Institute of Cybersecurity and Cryptology, School of Computing and Information Technology, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia"}]},{"given":"Minh Thuy Truc","family":"Pham","sequence":"additional","affiliation":[{"name":"Data Science, Deakin University, Melbourne, VIC 3125, Australia"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Galdi, C., and Kolesnikov, V. 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