Chrome proposes a different certificate system for the quantum era

Chrome’s team outlined a post-quantum HTTPS certificate programme on 27 February. Its proposed Merkle Tree Certificates replace the usual chain of signatures sent to a browser with a compact proof that a certificate belongs to a signed public tree. The aim is to limit the bandwidth cost of larger quantum-resistant cryptography.

Google described an experiment with Cloudflare that retained a trusted conventional certificate as a fallback. Its next proposed phases would involve existing Certificate Transparency log operators in early 2027, followed by a separate quantum-resistant root programme later that year. These were roadmap stages, not changes already deployed across the web. The existing Chrome Root Programme continues alongside the work.