--- title: Building a post-quantum certificate authority with... description: Cloudflare is launching its own certificate authority that will support Merkle Tree Certificates (MTCs), a new post-quantum certificate format designed to... canonical: https://daily.dev/posts/building-a-post-quantum-certificate-authority-with-merkle-tree-certificates-ws88fv7kp twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Building a post-quantum certificate authority with Merkle Tree Certificates | daily.dev og:description: Cloudflare is launching its own certificate authority that will support Merkle Tree Certificates (MTCs), a new post-quantum certificate format designed to... og:url: https://daily.dev/posts/building-a-post-quantum-certificate-authority-with-merkle-tree-certificates-ws88fv7kp og:image: https://api.daily.dev/og/posts/ws88fv7kP.png og:image:alt: Building a post-quantum certificate authority with Merkle Tree Certificates 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. # Building a post-quantum certificate authority with Merkle Tree Certificates **[Cloudflare](https://daily.dev/sources/cloudflare)** · 13 min read · 0 upvotes · 0 comments ## Summary Cloudflare is launching its own certificate authority that will support Merkle Tree Certificates (MTCs), a new post-quantum certificate format designed to scale efficiently across the Web PKI. MTCs batch certificate issuance into an append-only Merkle tree, letting clients verify compact inclusion proofs instead of validating large post-quantum signatures individually, addressing an estimated 40x increase in certificate transparency log storage from PQ signatures. Cloudflare is targeting early 2027 inclusion in Chrome's Quantum-resistant Root Store, will offer standard MTC issuance for free, is forking Let's Encrypt's Boulder for ACME issuance, and will run mirroring cosigners via its open-source Azul transparency log. An earlier 2026 experiment with Chrome Beta serving billions of MTCs to 50% of users showed landmark-relative certificates were 9% faster at median than classical certificate chains, with expectations of greater gains once real post-quantum signatures are used. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What are Merkle Tree Certificates (MTCs) and why are they needed for post-quantum TLS? Merkle Tree Certificates are a draft IETF specification (from the PLANTS working group) that batches certificates into an append-only Merkle tree so a CA signs one tree root instead of many individual certificates. This avoids sending full post-quantum signatures, which are roughly 40 times larger than classical ones, in every TLS handshake, and would otherwise balloon certificate transparency log storage by an estimated 40x. _Track how post-quantum TLS designs like MTCs evolve toward production readiness on daily.dev._ ### When will Cloudflare's certificate authority support MTC issuance in Chrome? Cloudflare's new certificate authority is targeting early 2027 for inclusion in Chrome's Quantum-resistant Root Store, and will provide standard MTC issuance at no cost. The CA will fork Let's Encrypt's Boulder software for ACME-based issuance and operate mirroring cosigners using Cloudflare's open-source Azul transparency log, implementing the c2sp tlog-mirror protocol for interoperability. _Developers planning ahead for post-quantum TLS adoption can follow CA and root store timelines on daily.dev._ ### How much faster are landmark-relative MTC certificates compared to classical certificate chains? In Cloudflare's 2026 experiment with Chrome Beta 146, landmark-relative MTCs were 9% faster at median than a classical signature chain, largely due to intermediate certificate elision. The experiment used classical signatures rather than actual post-quantum signatures, so the improvement is expected to be even larger once real PQ signatures are involved, since MTCs avoid transmitting heavyweight PQ signatures per handshake. _Anyone evaluating TLS handshake performance trade-offs for post-quantum readiness can follow these benchmarks on daily.dev._ ## Similar posts on daily.dev - [Keeping the Internet fast and secure: introducing Merkle Tree Certificates](https://daily.dev/posts/keeping-the-internet-fast-and-secure-introducing-merkle-tree-certificates-blu0ryjsr) · Cloudflare · 2 upvotes · 0 comments - [Cloudflare Proposes Merkle Tree Certificates to Solve Post-Quantum TLS Performance Issue](https://daily.dev/posts/cloudflare-proposes-merkle-tree-certificates-to-solve-post-quantum-tls-performance-issue-8jpwvx4ft) · InfoQ · 0 upvotes · 0 comments - [Web PKI Reimagined with Merkle Tree Certificates](https://daily.dev/posts/web-pki-reimagined-with-merkle-tree-certificates-ancuapixf) · Feisty Duck · 0 upvotes · 0 comments --- Tags: [#quantum-computing](https://daily.dev/tags/quantum-computing), [#cloudflare](https://daily.dev/tags/cloudflare) [View this post on daily.dev](https://daily.dev/posts/building-a-post-quantum-certificate-authority-with-merkle-tree-certificates-ws88fv7kp) ```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":"Building a post-quantum certificate authority with Merkle Tree Certificates","url":"https://daily.dev/posts/building-a-post-quantum-certificate-authority-with-merkle-tree-certificates-ws88fv7kp","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/building-a-post-quantum-certificate-authority-with-merkle-tree-certificates-ws88fv7kp"},"datePublished":"2026-09-29T13:06:41.811Z","dateModified":"2026-10-05T05:10:54.816Z","description":"Cloudflare is launching its own certificate authority that will support Merkle Tree Certificates (MTCs), a new post-quantum certificate format designed to...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/526b689d993da5642018ffd24e3326ef?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/526b689d993da5642018ffd24e3326ef?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Cloudflare","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":"Cloudflare","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/38522e1d11354cd6b7af66f9d4316735","url":"https://daily.dev/sources/cloudflare"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/building-a-post-quantum-certificate-authority-with-merkle-tree-certificates-ws88fv7kp","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"quantum-computing,cloudflare","timeRequired":"PT13M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Cloudflare","item":"https://daily.dev/sources/cloudflare"},{"@type":"ListItem","position":3,"name":"Building a post-quantum certificate authority with Merkle Tree Certificates"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/building-a-post-quantum-certificate-authority-with-merkle-tree-certificates-ws88fv7kp#faq","mainEntity":[{"@type":"Question","name":"What are Merkle Tree Certificates (MTCs) and why are they needed for post-quantum TLS?","acceptedAnswer":{"@type":"Answer","text":"Merkle Tree Certificates are a draft IETF specification (from the PLANTS working group) that batches certificates into an append-only Merkle tree so a CA signs one tree root instead of many individual certificates. 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