Continuous Key Refreshment for Hybrid Quantum Cryptography with BB84 and Post Quantum Signatures

Continuous Key Refreshment for Hybrid Quantum Cryptography with BB84 and Post Quantum Signatures | 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 Continuous Key Refreshment for Hybrid Quantum Cryptography with BB84 and Post Quantum Signatures Karthick V, Sharukeshwar P, Someshwar K M This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9215050/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The current paper presents a quantum-classical cryptographic protocol, which is a hybrid of the BB84 Quantum Key Distribution (QKD) protocol and a lattice-based post-quantum signature scheme, CRYSTALS-Dilithium. Such a mix is to create a safe channel of communication that is resistant to classical and quantum assaults. The protocol relies on the unconditional security of QKD to exchange keys in a symmetric way and addresses the vulnerability of QKD to man-in-the-middle (MitM) attacks by strong classical authentication provided by PQC signatures. Another important invention of this work is the ever-refreshing of the keys. This is to enable the periodic updating of the session key without necessarily having to undergo the entire re-authentication two-way handshake. This is enhanced to improve forward secrecy and reduce the computational requirements. To demonstrate the viability and security aspects of the protocol, we give a theoretical framework and a simulation of the protocol by IBMs Qiskit. The protocol showed that it was able to generate secure keys successfully which was in line with the theoretical expectations. The embedded CRYSTALS-Dilithium signature provides effective authentication that ensures that the hybrid system is viable and does not cause any performance problem. The simulation results quantitatively validate the protocol's security and performance, demonstrating a QBER of 0.7% under ideal conditions, which is well below the 25% abort threshold. These findings indicate that this mixed solution is an effective solution to secure long-term communications in the quantum age. Quantum computing Quantum Cryptography Superposition QKD (Quantum Key Distribution) BB84 Polarization PQC (Post Quantum Cryptography) MitM (Man in the Middle) Continuous Key Refreshment Cycle (CKRC) PQC Authentication Layer Secure Key Rate (SKR) CRYSTAL (Cryptographic Suite for Algebraic Lattices) QBER (Quantum Bit Error Rate) Decoy State Method Decoy State Lattice-based digital signatures Dilithium Hybrid Protocol hybrid System Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-9215050","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":614762574,"identity":"8b0cb614-9131-4e2d-aa3f-d588e1e2cf6e","order_by":0,"name":"Karthick V","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6UlEQVRIiWNgGAWjYDACHiBmbJBgkGBvPvgAxOcjSstBkBaeY8kGID4bkVoYGCQkctQkQAIEtRicOfzs88cdFvKSPWfYKr/m2MmwMTA/fHQDn5azbcYzDp6RMJzN3nvstuy2ZKDD2IyNc/BokexnMGY42CaRIMdzLu225DZmoBYeNmn8Wtg/Q7RI5JgVS26rJ6yFn7cHYos0UAvjx22HidDCc6aY4WybhOHMnmPJ0ozbjvOwMRPwCxtP+maGyrY6eYnjzQc//txWbc/P3vzwMT4tKICZB0wSqxwEGH+QonoUjIJRMApGDAAA6HlEfIkyme0AAAAASUVORK5CYII=","orcid":"","institution":"Rajalakshmi Engineering College, Anna University","correspondingAuthor":true,"prefix":"","firstName":"Karthick","middleName":"","lastName":"V","suffix":""},{"id":614762575,"identity":"6558e1bb-d2d8-4347-8172-893767cb606a","order_by":1,"name":"Sharukeshwar P","email":"","orcid":"","institution":"Rajalakshmi Engineering College, Anna University","correspondingAuthor":false,"prefix":"","firstName":"Sharukeshwar","middleName":"","lastName":"P","suffix":""},{"id":614762578,"identity":"a6af8ccd-afd5-4f66-b486-e2d64b2e07b7","order_by":2,"name":"Someshwar K M","email":"","orcid":"","institution":"Rajalakshmi Engineering College, Anna University","correspondingAuthor":false,"prefix":"","firstName":"Someshwar","middleName":"K","lastName":"M","suffix":""}],"badges":[],"createdAt":"2026-03-24 17:53:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9215050/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9215050/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106796966,"identity":"e835eb44-870c-46b3-8619-b0918e1636c2","added_by":"auto","created_at":"2026-04-13 14:12:57","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":693246,"visible":true,"origin":"","legend":"","description":"","filename":"ContinuousKeyRefreshmentinHybridQuantumCryptographyIntegratingBB84withPostQuantumSignatures.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9215050/v1_covered_5307ae00-4ae0-4f98-b8c0-09e268e8156c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Continuous Key Refreshment for Hybrid Quantum Cryptography with BB84 and Post Quantum Signatures","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Quantum computing, Quantum Cryptography, Superposition, QKD (Quantum Key Distribution), BB84, Polarization, PQC (Post Quantum Cryptography), MitM (Man in the Middle), Continuous Key Refreshment Cycle (CKRC), PQC Authentication Layer, Secure Key Rate (SKR), CRYSTAL (Cryptographic Suite for Algebraic Lattices), QBER (Quantum Bit Error Rate), Decoy State Method, Decoy State, Lattice-based digital signatures, Dilithium, Hybrid Protocol, hybrid System","lastPublishedDoi":"10.21203/rs.3.rs-9215050/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9215050/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe current paper presents a quantum-classical cryptographic protocol, which is a hybrid of the BB84 Quantum Key Distribution (QKD) protocol and a lattice-based post-quantum signature scheme, CRYSTALS-Dilithium. Such a mix is to create a safe channel of communication that is resistant to classical and quantum assaults. The protocol relies on the unconditional security of QKD to exchange keys in a symmetric way and addresses the vulnerability of QKD to man-in-the-middle (MitM) attacks by strong classical authentication provided by PQC signatures. Another important invention of this work is the ever-refreshing of the keys. This is to enable the periodic updating of the session key without necessarily having to undergo the entire re-authentication two-way handshake. This is enhanced to improve forward secrecy and reduce the computational requirements. To demonstrate the viability and security aspects of the protocol, we give a theoretical framework and a simulation of the protocol by IBMs Qiskit. The protocol showed that it was able to generate secure keys successfully which was in line with the theoretical expectations. The embedded CRYSTALS-Dilithium signature provides effective authentication that ensures that the hybrid system is viable and does not cause any performance problem. The simulation results quantitatively validate the protocol's security and performance, demonstrating a QBER of 0.7% under ideal conditions, which is well below the 25% abort threshold. These findings indicate that this mixed solution is an effective solution to secure long-term communications in the quantum age.\u003c/p\u003e","manuscriptTitle":"Continuous Key Refreshment for Hybrid Quantum Cryptography with BB84 and Post Quantum Signatures","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-01 07:07:04","doi":"10.21203/rs.3.rs-9215050/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2be60dcd-7a4c-41d0-85d2-f98b447e5f93","owner":[],"postedDate":"April 1st, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-13T14:09:54+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-01 07:07:04","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9215050","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9215050","identity":"rs-9215050","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}