--- title: QNu Labs, BISAG-N and IIT Gandhinagar Demonstrate 5... description: QNu Labs, BISAG-N and IIT Gandhinagar demonstrated a 5.56 km free-space quantum key distribution (QKD) link, India's first at this scale, conducted overnight... canonical: https://daily.dev/posts/qnu-labs-bisag-n-and-iit-gandhinagar-demonstrate-5-km-scale-free-space-qkd-link-1warlekom twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: QNu Labs, BISAG-N and IIT Gandhinagar Demonstrate 5 km-Scale Free-Space QKD Link | daily.dev og:description: QNu Labs, BISAG-N and IIT Gandhinagar demonstrated a 5.56 km free-space quantum key distribution (QKD) link, India's first at this scale, conducted overnight... og:url: https://daily.dev/posts/qnu-labs-bisag-n-and-iit-gandhinagar-demonstrate-5-km-scale-free-space-qkd-link-1warlekom og:image: https://api.daily.dev/og/posts/1wArLEkom.png og:image:alt: QNu Labs, BISAG-N and IIT Gandhinagar Demonstrate 5 km-Scale Free-Space QKD Link og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # QNu Labs, BISAG-N and IIT Gandhinagar Demonstrate 5 km-Scale Free-Space QKD Link **[The Quantum Insider](https://daily.dev/sources/thequantuminsider)** · 4 min read · 0 upvotes · 0 comments ## Summary QNu Labs, BISAG-N and IIT Gandhinagar demonstrated a 5.56 km free-space quantum key distribution (QKD) link, India's first at this scale, conducted overnight on September 27-28, 2026. The trial achieved a secure key rate of 230-260 bits per second with a quantum bit error rate below 5%, using the DPS-Decoy QKD protocol and a 1550 nm quantum channel maintained by a precision pointing, acquisition and tracking system. The demonstration integrated QKD-generated keys with BISAG-N's Vedic Kavach post-quantum cryptography browser and web server via the ETSI GS QKD 014 interface, successfully encrypting, transmitting and decrypting a test message. The hybrid architecture is designed to stay operational via post-quantum cryptography and quantum random number generation even if the physical quantum channel is interrupted, positioning the project as a step toward longer-distance and eventually satellite-based quantum communication. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What secure key rate did the QNu Labs free-space QKD trial achieve over 5.56 km? The trial achieved a secure key rate of 230-260 bits per second with a quantum bit error rate below 5%. Conducted between BISAG-N and IIT Gandhinagar on the night of September 27-28, 2026, it used the DPS-Decoy QKD protocol over a 1550 nm quantum channel, generating roughly one fresh 256-bit key per second. _Teams evaluating QKD feasibility can track emerging field trial results like this one on daily.dev._ ### How does QNu Labs combine QKD with post-quantum cryptography in a hybrid security architecture? QKD provides hardware-based key distribution over a free-space optical channel while a software layer, BISAG-N's Vedic Kavach, supplies post-quantum cryptography and quantum random number generation. The architecture keeps the application protected even if the physical quantum channel becomes temporarily unavailable, with keys delivered through the ETSI GS QKD 014 interface in 256-bit chunks. _Engineers designing quantum-resilient systems can follow hybrid QKD-PQC architecture developments on daily.dev._ ### What pointing accuracy is needed to maintain a free-space QKD link over several kilometers? The QNu Labs pointing, acquisition and tracking (PAT) system achieved coarse pointing accuracy of 5 microradians via a gimbal and fine pointing accuracy of up to 0.1 microradians using 100 Hz tracking, keeping the quantum channel aligned across a 5.56 km open-atmosphere link despite atmospheric conditions and physical movement. _Researchers building free-space optical links can keep up with pointing and tracking benchmarks on daily.dev._ ## Similar posts on daily.dev - [Quantum Keys Travel 18 Kilometers Across Hybrid Air-and-Fiber Network](https://daily.dev/posts/quantum-keys-travel-18-kilometers-across-hybrid-air-and-fiber-network-siajl2xwo) · The Quantum Insider · 0 upvotes · 0 comments - [Quantum key distribution enables secure communication via hybrid and mobile channels](https://daily.dev/posts/quantum-key-distribution-enables-secure-communication-via-hybrid-and-mobile-channels-2ts4dij6i) · Phys.org · 1 upvotes · 0 comments - [Large-scale quantum communication networks with integrated photonics](https://daily.dev/posts/large-scale-quantum-communication-networks-with-integrated-photonics-ellxuk3yq) · Nature · 0 upvotes · 0 comments - [Quantum Networking Beyond the Lab](https://daily.dev/posts/quantum-networking-beyond-the-lab-urd4afvut) · Cisco · 1 upvotes · 0 comments - [Scientists Send Secure Quantum Keys Over 62 Miles of Fiber—Without Trusted Devices](https://daily.dev/posts/scientists-send-secure-quantum-keys-over-62-miles-of-fiber-without-trusted-devices-x0fgu1nl6) · Singularity Hub · 0 upvotes · 0 comments --- Tags: [#quantum-computing](https://daily.dev/tags/quantum-computing), [#cryptography](https://daily.dev/tags/cryptography) [View this post on daily.dev](https://daily.dev/posts/qnu-labs-bisag-n-and-iit-gandhinagar-demonstrate-5-km-scale-free-space-qkd-link-1warlekom) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"QNu Labs, BISAG-N and IIT Gandhinagar Demonstrate 5 km-Scale Free-Space QKD Link","url":"https://daily.dev/posts/qnu-labs-bisag-n-and-iit-gandhinagar-demonstrate-5-km-scale-free-space-qkd-link-1warlekom","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/qnu-labs-bisag-n-and-iit-gandhinagar-demonstrate-5-km-scale-free-space-qkd-link-1warlekom"},"datePublished":"2026-10-05T08:35:09.079Z","dateModified":"2026-10-05T08:35:30.150Z","description":"QNu Labs, BISAG-N and IIT Gandhinagar demonstrated a 5.56 km free-space quantum key distribution (QKD) link, India's first at this scale, conducted overnight...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/b3e11d842ed83752a40cc6a6605e3743?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/b3e11d842ed83752a40cc6a6605e3743?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"The Quantum Insider","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"The Quantum Insider","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/7b14a6b34c1b464c9e8a88d9a0dac951","url":"https://daily.dev/sources/thequantuminsider"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/qnu-labs-bisag-n-and-iit-gandhinagar-demonstrate-5-km-scale-free-space-qkd-link-1warlekom","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"quantum-computing,cryptography","timeRequired":"PT4M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"The Quantum Insider","item":"https://daily.dev/sources/thequantuminsider"},{"@type":"ListItem","position":3,"name":"QNu Labs, BISAG-N and IIT Gandhinagar Demonstrate 5 km-Scale Free-Space QKD Link"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/qnu-labs-bisag-n-and-iit-gandhinagar-demonstrate-5-km-scale-free-space-qkd-link-1warlekom#faq","mainEntity":[{"@type":"Question","name":"What secure key rate did the QNu Labs free-space QKD trial achieve over 5.56 km?","acceptedAnswer":{"@type":"Answer","text":"The trial achieved a secure key rate of 230-260 bits per second with a quantum bit error rate below 5%. 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