A Post-Quantum Future for Let's Encrypt
Summary
Let’s Encrypt outlines a plan to adopt Merkle Tree Certificates (MTCs) to enable post-quantum authentication in the Web PKI, addressing handshake size and the need for post-quantum signatures. The article explains MTCs' batching and built-in certificate transparency, and lays out a timeline for staging in late 2026 and production in 2027, with related standards work (ML-DSA, RFC 9881) and ecosystem changes (ACME, browser support). It also advises operators to monitor PLANTS and mtcs mailing lists as the ecosystem evolves.