Google Chrome Introduces Merkle Tree Certificates to Protect HTTPS from Quantum Attacks

**Executive summary:** Google Chrome is introducing Merkle Tree Certificates (MTCs) as a quantum-resistant alternative to large post-quantum X.509 certificate chains, aiming to preserve TLS handshake performance while providing built-in transparency and scalability; a three-phase rollout includes a Cloudflare feasibility study (phase 1), CT log operator bootstrapping (Q1 2027), and a Chrome Quantum-resistant Root Store launch (Q3 2027), with Chrome maintaining support for current CAs during the transition.