--- title: Harvest Now, Decrypt Later: The Threat to Key Exchange –... description: Quantum computers pose a delayed but urgent threat to classical key exchange via the 'harvest now, decrypt later' attack — adversaries record encrypted traffic... canonical: https://daily.dev/posts/harvest-now-decrypt-later-the-threat-to-key-exchange-quantum-series-part-2-eadei5fjg twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Harvest Now, Decrypt Later: The Threat to Key Exchange – Quantum Series, Part 2 | daily.dev og:description: Quantum computers pose a delayed but urgent threat to classical key exchange via the 'harvest now, decrypt later' attack — adversaries record encrypted traffic... og:url: https://daily.dev/posts/harvest-now-decrypt-later-the-threat-to-key-exchange-quantum-series-part-2-eadei5fjg og:image: https://api.daily.dev/og/posts/eaDEi5FJG.png og:image:alt: Harvest Now, Decrypt Later: The Threat to Key Exchange – Quantum Series, Part 2 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. # Harvest Now, Decrypt Later: The Threat to Key Exchange – Quantum Series, Part 2 **[Cisco](https://daily.dev/sources/cisco)** · 6 min read · 0 upvotes · 0 comments ## Summary Quantum computers pose a delayed but urgent threat to classical key exchange via the 'harvest now, decrypt later' attack — adversaries record encrypted traffic today and decrypt it once quantum hardware matures. Diffie-Hellman (including X25519/ECDH) is vulnerable to Shor's algorithm, making any long-lived sensitive data transmitted today at risk. ML-KEM (FIPS 203), NIST's standardized post-quantum Key Encapsulation Mechanism, is introduced as the quantum-safe alternative. Unlike DH's symmetric exchange, ML-KEM uses an asymmetric encapsulate/decapsulate model. ML-KEM-768 is recommended as the practical sweet spot. The post previews a hybrid approach combining both algorithms, to be detailed in Part 3. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [The Quantum Threat to Encryption: Why Lattice Cryptography is Your New Best Friend](https://daily.dev/posts/the-quantum-threat-to-encryption-why-lattice-cryptography-is-your-new-best-friend-r8htu0zlo) · InfoSec Write-ups · 0 upvotes · 0 comments - [‘Harvest now, decipher later’: The quantum threat few are preparing for](https://daily.dev/posts/harvest-now-decipher-later-the-quantum-threat-few-are-preparing-for-lzhdrjp4j) · CSO Online · 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/harvest-now-decrypt-later-the-threat-to-key-exchange-quantum-series-part-2-eadei5fjg) ```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":"Harvest Now, Decrypt Later: The Threat to Key Exchange – Quantum Series, Part 2","url":"https://daily.dev/posts/harvest-now-decrypt-later-the-threat-to-key-exchange-quantum-series-part-2-eadei5fjg","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/harvest-now-decrypt-later-the-threat-to-key-exchange-quantum-series-part-2-eadei5fjg"},"datePublished":"2026-07-13T14:05:40.843Z","dateModified":"2026-07-13T14:06:03.962Z","description":"Quantum computers pose a delayed but urgent threat to classical key exchange via the 'harvest now, decrypt later' attack — adversaries record encrypted traffic...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/abffb8f08da040d2d90613f0f6e12c43?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/abffb8f08da040d2d90613f0f6e12c43?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Cisco","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":"Cisco","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/68b8a8be17184235a5067d7c84162f77","url":"https://daily.dev/sources/cisco"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/harvest-now-decrypt-later-the-threat-to-key-exchange-quantum-series-part-2-eadei5fjg","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"quantum-computing,cryptography","timeRequired":"PT6M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Cisco","item":"https://daily.dev/sources/cisco"},{"@type":"ListItem","position":3,"name":"Harvest Now, Decrypt Later: The Threat to Key Exchange – Quantum Series, Part 2"}]} ```