Let's Encrypt Works Toward Post-Quantum Certificates at Web Scale
Help Net Security, Friday, June 5th, 2026
Let's Encrypt plans to deploy Merkle Tree Certificates for post-quantum web authentication, targeting staging in late 2026.
Let's Encrypt is developing Merkle Tree Certificates (MTCs) to add post-quantum authentication to the web while preserving TLS efficiency.
The effort addresses fears that quantum computers could forge signatures in real time, threatening long-lived keys in root certificate authorities and code-signing systems.
Traditional post-quantum signature algorithms create impractically large TLS handshakes; MTCs solve this by issuing certificates in batches with a single signature covering many certificates rather than signing each one individually.
A staging environment is targeted for late 2026, with production planned for 2027, aligning with NSA, NIST, and EU timelines directing post-quantum migration between 2030 and 2035. Major firms including Google and Cloudflare have committed to post-quantum transitions by 2029.