Google has unveiled a new initiative within its Chrome browser aimed at strengthening HTTPS security against the long term threat of quantum computing. The move represents a significant step toward building a quantum-resistant internet without sacrificing speed or scalability.
In a statement from the Chrome Secure Web and Networking Team, Google clarified that it does not plan to directly integrate traditional X.509 certificates containing post-quantum cryptography into the Chrome Root Store at this time. Instead, the company is developing an alternative framework based on Merkle Tree Certificates, commonly referred to as MTCs.
This work is currently progressing within the PLANTS working group and is being developed in coordination with industry partners.
What Are Merkle Tree Certificates
Merkle Tree Certificates are designed as a next generation enhancement to the Public Key Infrastructure system that underpins secure web communication. The goal is to streamline the Transport Layer Security handshake process by minimizing the number of public keys and digital signatures exchanged during authentication.
Under this model, a Certification Authority signs a single structure known as a Tree Head. This Tree Head can represent millions of individual certificates. When a user connects to a website, the browser receives a compact proof that the certificate belongs within that signed tree, rather than processing a traditional certificate chain.
This structure dramatically reduces data overhead while preserving strong cryptographic guarantees.
Enabling Post-Quantum Cryptography Without Performance Loss
One of the primary challenges of post-quantum cryptography is its increased data size. Classical X.509 certificate chains can become significantly larger when quantum-resistant algorithms are added, potentially slowing down TLS connections.
Google explained that MTCs allow the adoption of post-quantum algorithms without increasing bandwidth consumption. By separating cryptographic strength from transmitted certificate size, the approach maintains efficient data transfer while strengthening long term security.
By minimizing authentication data during the TLS handshake, MTCs aim to ensure that the post-quantum web remains as fast and responsive as today’s internet experience.
Three Phase Rollout Plan Through 2027
Google has already begun testing Merkle Tree Certificates using real world internet traffic. The company confirmed that deployment will expand gradually in three structured phases, targeting broader implementation by the third quarter of 2027.
Phase 1, Currently Underway
Google is collaborating with Cloudflare in a feasibility study to measure performance, scalability, and security impacts of TLS connections powered by MTCs.
Phase 2, First Quarter 2027
The company plans to invite Certificate Transparency Log operators that had at least one usable log in Chrome before February 1, 2026, to participate in the initial public bootstrapping of MTC infrastructure.
Phase 3, Third Quarter 2027
Google intends to establish final onboarding requirements for additional Certification Authorities within the new Chrome Quantum-resistant Root Store, abbreviated as CQRS. This root program will exclusively support Merkle Tree Certificates.
Building a Quantum-Resilient Web Ecosystem
Google emphasized that transitioning to MTCs and launching a quantum-resistant root store represents a foundational upgrade for internet security. The company views this effort as essential to maintaining trust, performance, and resilience in a future shaped by quantum computing advancements.
By designing infrastructure tailored for modern internet demands, Google aims to accelerate the adoption of post-quantum cryptography while preserving the seamless browsing experience users expect.
The initiative signals a major shift in HTTPS certificate architecture and may influence broader industry adoption of quantum-resistant security standards.
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