CCA-attacks on lattice-based encryption-decryption schemes

CCA-attacks on lattice-based encryption-decryption schemes | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article CCA-attacks on lattice-based encryption-decryption schemes Alba Hernandez Costoya, Alba Larraya Sancho, Miguel Ángel Marco Buzunáriz This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7013862/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 21 Oct, 2025 Read the published version in Cryptography and Communications → Version 1 posted 9 You are reading this latest preprint version Abstract This paper presents two distinct chosen-ciphertext attacks (CCA) against latticebased encryption and decryption schemes, in particular based on the LWE problem, a class of post-quantum cryptographic algorithms. First we attack fully homomorphic encryption-decryption schemes (FHE) exploiting the additional information that the small modulus reduction offers. We compare this attack with the CPA D attack presented in [1]. Afterwards we present an attack against the CPA secure encryption decryption Kyber scheme and another against the CPA Kyber KEM, and compare them to the previous Key Mismatch Attack in [2]. Our work remarks the importance of protecting the decryption function in the different implementations of these cryptographic schemes, and the importance of CCA security in nowadays cryptosystems. MSC Classification: 94a60 Learning With Errors CCA-attacks Lattice-based cryptography Fully homomorphic encryption Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 21 Oct, 2025 Read the published version in Cryptography and Communications → Version 1 posted Editorial decision: Revision requested 31 Jul, 2025 Reviews received at journal 30 Jul, 2025 Reviews received at journal 17 Jul, 2025 Reviewers agreed at journal 09 Jul, 2025 Reviewers agreed at journal 02 Jul, 2025 Reviewers invited by journal 01 Jul, 2025 Editor assigned by journal 01 Jul, 2025 Submission checks completed at journal 01 Jul, 2025 First submitted to journal 30 Jun, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7013862","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":479406736,"identity":"ff11cc5a-4990-4169-b2c3-0dc148904dc7","order_by":0,"name":"Alba Hernandez Costoya","email":"","orcid":"","institution":"Universidad del País Vasco","correspondingAuthor":false,"prefix":"","firstName":"Alba","middleName":"Hernandez","lastName":"Costoya","suffix":""},{"id":479406738,"identity":"7cdd8154-d327-43af-b6b5-530303d075d7","order_by":1,"name":"Alba Larraya Sancho","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA60lEQVRIiWNgGAWjYDACdijNLwGhEwhrYYbSkjPAlAEJWgxuEKuFv5n52eeKmsPyxrebH366UfMnj4G99/ELfFokDrMZzzxz7LDhtjvHjKVzjhkUM/AcN7PAa81hBmPGBrbDjNtu5DBI57AZJDZIpLEZ4NMhf5j9M2PDv8P2m2fkMP/O+UeEFoPDPMaMjW2HEzdI5LBJ57aBtTA/wKfF8DBPMWNjX3ryjDvHzKxz+4wT23iOseH1itzx9s2MDd+sbftnNz++nfNNLrGfvY35A149ENCMYAKtYJMgQksdCo8oW0bBKBgFo2DkAAAOjkluBsRazgAAAABJRU5ErkJggg==","orcid":"","institution":"Basque Center for Applied Mathematics","correspondingAuthor":true,"prefix":"","firstName":"Alba","middleName":"Larraya","lastName":"Sancho","suffix":""},{"id":479406739,"identity":"82201449-e043-4b7c-bd03-f51cf6c1d04d","order_by":2,"name":"Miguel Ángel Marco Buzunáriz","email":"","orcid":"","institution":"Universidad de Zaragoza","correspondingAuthor":false,"prefix":"","firstName":"Miguel","middleName":"Ángel Marco","lastName":"Buzunáriz","suffix":""}],"badges":[],"createdAt":"2025-06-30 19:53:21","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7013862/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7013862/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s12095-025-00837-z","type":"published","date":"2025-10-21T16:16:37+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":94489961,"identity":"b38654ed-1d7b-481e-b51c-6fba8f038df5","added_by":"auto","created_at":"2025-10-27 17:06:45","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":352598,"visible":true,"origin":"","legend":"","description":"","filename":"CCAattacksonlatticebasedencryptiondecryptionschemes.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7013862/v1_covered_953a3136-fc09-4168-a1f5-081d59e8b86e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"CCA-attacks on lattice-based encryption-decryption schemes","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"cryptography-and-communications","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ccds","sideBox":"Learn more about [Cryptography and Communications](http://link.springer.com/journal/12095)","snPcode":"12095","submissionUrl":"https://submission.nature.com/new-submission/12095/3","title":"Cryptography and Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Learning With Errors, CCA-attacks, Lattice-based cryptography, Fully homomorphic encryption","lastPublishedDoi":"10.21203/rs.3.rs-7013862/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7013862/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis paper presents two distinct chosen-ciphertext attacks (CCA) against latticebased encryption and decryption schemes, in particular based on the LWE problem, a class of post-quantum cryptographic algorithms. 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