“MTCs replace the heavy, serialized chain of signatures found in traditional PKI with compact Merkle Tree proofs.”
Google is swapping out traditional X.509 certificate chains for Merkle Tree Certificates to make HTTPS quantum-resistant. The compression trick is real: 2.5kB of cryptographic data squeezed into 64 bytes while layering in post-quantum algorithms. Full rollout is a 2027 project, which means the quantum threat isn’t exactly imminent. Google is moving the web’s PKI infrastructure on their own timeline regardless of whether anyone asked.