{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T14:27:17Z","timestamp":1782829637989,"version":"3.54.5"},"reference-count":22,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2025,9,8]],"date-time":"2025-09-08T00:00:00Z","timestamp":1757289600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["62272232"],"award-info":[{"award-number":["62272232"]}]},{"name":"National Natural Science Foundation of China","award":["62172224"],"award-info":[{"award-number":["62172224"]}]},{"name":"National Natural Science Foundation of China","award":["2025201015"],"award-info":[{"award-number":["2025201015"]}]},{"name":"National Natural Science Foundation of China","award":["LNCT2022-A22"],"award-info":[{"award-number":["LNCT2022-A22"]}]},{"name":"Fundamental Research Funds for the Central Universities","award":["62272232"],"award-info":[{"award-number":["62272232"]}]},{"name":"Fundamental Research Funds for the Central Universities","award":["62172224"],"award-info":[{"award-number":["62172224"]}]},{"name":"Fundamental Research Funds for the Central Universities","award":["2025201015"],"award-info":[{"award-number":["2025201015"]}]},{"name":"Fundamental Research Funds for the Central Universities","award":["LNCT2022-A22"],"award-info":[{"award-number":["LNCT2022-A22"]}]},{"name":"Henan Key Laboratory of Network Cryptography Technology","award":["62272232"],"award-info":[{"award-number":["62272232"]}]},{"name":"Henan Key Laboratory of Network Cryptography Technology","award":["62172224"],"award-info":[{"award-number":["62172224"]}]},{"name":"Henan Key Laboratory of Network Cryptography Technology","award":["2025201015"],"award-info":[{"award-number":["2025201015"]}]},{"name":"Henan Key Laboratory of Network Cryptography Technology","award":["LNCT2022-A22"],"award-info":[{"award-number":["LNCT2022-A22"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>Side-channel analysis (SCA) poses a persistent threat to cryptographic hardware by exploiting unintended physical leakages. To address the limitations of traditional single-modality SCA methods, we propose a novel multi-modal side-channel analysis framework that targets the recovery of encryption keys by leveraging the imperfections inherent in hardware implementations. The core objective is to extract and classify information-rich segments from power and electromagnetic (EM) signals in order to recover secret keys without profiling or labeling. Our approach introduces a unified pipeline combining joint peak-based segmentation, isometric compression of variable-length trace segments, and multi-modal feature fusion. A key component of the framework is unsupervised clustering, which serves to automatically classify trace segments corresponding to different cryptographic operations (e.g., different key-dependent leakage classes), thereby enabling key byte hypothesis testing and full key reconstruction. Experimental results on an FPGA-based AES-128 implementation demonstrate that our method achieves up to 99.2% clustering accuracy and successfully recovers the entire encryption key using as few as 1\u20133 traces. Moreover, the proposed approach significantly reduces sample complexity and maintains resilience in low signal-to-noise conditions. These results highlight the practicality of our technique for side-channel vulnerability assessment and its potential to inform the design of more robust cryptographic hardware.<\/jats:p>","DOI":"10.3390\/sym17091483","type":"journal-article","created":{"date-parts":[[2025,9,8]],"date-time":"2025-09-08T10:29:07Z","timestamp":1757327347000},"page":"1483","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Multi-Modal Side-Channel Analysis Based on Isometric Compression and Combined Clustering"],"prefix":"10.3390","volume":"17","author":[{"given":"Xiaoyong","family":"Kou","sequence":"first","affiliation":[{"name":"School of Computer Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7546-4465","authenticated-orcid":false,"given":"Wei","family":"Yang","sequence":"additional","affiliation":[{"name":"School of Computer Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lunbo","family":"Li","sequence":"additional","affiliation":[{"name":"School of Computer Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2925-5624","authenticated-orcid":false,"given":"Gongxuan","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Computer Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Kocher, P., Jaffe, J., and Jun, B. (1999, January 15\u201319). Differential Power Analysis. Proceedings of the Annual International Cryptology Conference (CRYPTO), Santa Barbara, CA, USA.","DOI":"10.1007\/3-540-48405-1_25"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Chari, S., Rao, J.R., and Rohatgi, P. (2002, January 13\u201315). Template Attacks. Proceedings of the Cryptographic Hardware and Embedded Systems (CHES), Redwood Shores, CA, USA.","DOI":"10.1007\/3-540-36400-5_3"},{"key":"ref_3","first-page":"1","article-title":"A Review and Comparison of AI Enhanced Side Channel Analysis","volume":"20","author":"Panoff","year":"2024","journal-title":"ACM J. Emerg. Technol. Comput. Syst."},{"key":"ref_4","unstructured":"Ninan, M., Nimmo, E., Reilly, S., Smith, C., Sun, W., Wang, B., and Emmert, J.M. (October, January 30). A Second Look at the Portability of Deep Learning Side-Channel Attacks over EM Traces. 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Res."}],"container-title":["Symmetry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-8994\/17\/9\/1483\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:41:52Z","timestamp":1760035312000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-8994\/17\/9\/1483"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,9,8]]},"references-count":22,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2025,9]]}},"alternative-id":["sym17091483"],"URL":"https:\/\/doi.org\/10.3390\/sym17091483","relation":{},"ISSN":["2073-8994"],"issn-type":[{"value":"2073-8994","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,9,8]]}}}