Cultivating a robust and efficient quantum-safe HTTPS

Posted by Chrome Secure Web and Networking Team Today we're announcing a new program in Chrome to make HTTPS certificates secure against quantum computers. The Internet Engineering Task Force (IETF) recently created a working group, PKI, Logs, And Tree Signatures (“PLANTS”), aiming to address the performance and bandwidth challenges that the increased size of quantum-resistant cryptography introduces into TLS connections requiring Certificate Transparency (CT). We recently shared our call to action to secure quantum computing and have written about challenges introduced by quantum-resistant cryptography and some of the steps we’ve taken to address them in earlier blog posts. To ensure the scalability and efficiency of the ecosystem, Chrome has no immediate plan to add traditional X.509 certificates containing post-quantum cryptography to the Chrome Root Store. Instead, Chrome, in collaboration with other partners, is developing an evolution of HTTPS certificates based on Merkle Tree Certificates (MTCs), currently in development in the PLANTS working group. MTCs replace the heavy, serialized chain of signatures found in traditional PKI with compact Merkle Tree proofs. In this model, a Certification Authority (CA) signs a single "Tree Head" representing potentially millions of certificates, and the "certificate" sent to the browser is merely a lightweight proof of inclusion in that tree. Why MTCs? MTCs enable the adoption of robust post-quantum algorithms without incurring the massive bandwidth penalty of classical X.509 certificate chains. They also decouple the security strength of the corresponding cryptographic algorithm from the size of the data transmitted to the user. By shrinking the authentication data in a TLS handshake to the absolute minimum, MTCs aim to keep...

Original source: http://security.googleblog.com/2026/02/cultivating-robust-and-efficient.html
Publisher: Google Security Blog