Google Prepares Chrome for the Post-Quantum Internet With New HTTPS Security Program

The initiative, called PLANTS, introduces Merkle Tree Certificates to protect HTTPS connections from future quantum computer threats while maintaining browser performance.

Key Highlights

• Google has introduced PLANTS (PKI, Logs And Tree Signatures) to prepare Chrome for the post-quantum internet.
• The program aims to make HTTPS certificates resistant to quantum computer attacks.
• It proposes Merkle Tree Certificates (MTCs) to reduce performance and bandwidth issues.
• Traditional quantum-safe cryptography could be up to 40 times larger than current cryptography.
• Google is testing the new certificate system with partners like Cloudflare and plans a phased rollout through 2027.

Google Introduces PLANTS Program to Secure HTTPS Against Quantum Threats

Google has announced a new initiative aimed at ensuring that HTTPS certificates remain secure in the era of quantum computing. The program, known as PLANTS - PKI, Logs And Tree Signatures, focuses on addressing the performance and bandwidth challenges associated with quantum-resistant cryptography used in TLS connections that require Certificate Transparency (CT).

Quantum computers could eventually break many of the cryptographic systems currently used to secure internet communications. Simply replacing existing certificates with quantum-resistant cryptography would significantly increase certificate sizes, potentially slowing down browsers and increasing network bandwidth usage.

Bas Westerbaan, a research engineer at Cloudflare, explained that today’s cryptography used for secure connections is extremely compact and efficient. However, quantum-resistant cryptography can be dramatically larger, creating new technical challenges for web connections.

Why Post-Quantum Security Creates Performance Challenges

Browsers process billions of TLS connections every day and certificate authentication plays a critical role in how quickly web pages load.

Rebecca Krauthamer, CEO and co-founder of QuSecure, noted that public web handshakes currently include multiple signatures and keys because of certificate chains and Certificate Transparency proofs. These systems worked efficiently with smaller cryptographic signatures, but post-quantum cryptography involves significantly larger keys and signatures.

As a result, larger cryptographic data could increase the number of bytes transmitted during TLS handshakes, potentially slowing connections and creating additional network congestion, particularly on limited-bandwidth networks.

Google’s Solution: Merkle Tree Certificates

To address these challenges, Google is proposing an evolution of HTTPS certificates called Merkle Tree Certificates (MTCs).

Instead of relying on the traditional serialized chain of signatures used in the existing Public Key Infrastructure (PKI), MTCs use compact cryptographic proofs based on a Merkle tree structure. Under this model, a Certification Authority signs a single “Tree Head” that represents potentially millions of certificates.

When a browser connects to a website, it receives only a lightweight proof confirming that the certificate exists within that signed tree. This significantly reduces the amount of data transmitted during the TLS handshake while still enabling strong post-quantum security.

Google says this approach decouples cryptographic strength from data size, helping maintain fast browsing speeds even when stronger quantum-safe algorithms are used.

Challenges and Ecosystem Changes Ahead

While the proposed system could solve many performance and bandwidth concerns, experts say it introduces a new ecosystem of dependencies.

Jeremy Samuelson, executive vice president of AI and innovation at Integrated Quantum Technologies, said that although MTCs are promising, adopting them will create operational challenges due to the new infrastructure required.

Security experts also warn that transitioning to this new certificate architecture will require updates across software, firmware and hardware systems currently designed around traditional TLS certificate models.

Roger Grimes, CISO advisor at KnowBe4, noted that this represents a completely new approach to digital certificates and TLS, meaning legacy systems may need to be updated or replaced.

Preparing the Web for the Quantum Era

Experts say the move reflects a broader industry shift from theoretical discussions about quantum threats to practical implementation of defenses.

Antonio Sanchez, chief strategy officer at Quantum XChange, said the initiative highlights the urgency of protecting organizations against “harvest now, decrypt later” attacks, where encrypted data is collected today with the intention of decrypting it in the future using quantum computers.

Industry leaders also emphasize that transitioning to post-quantum cryptography is not simply a software update. Instead, it requires a major architectural transformation of the internet’s trust infrastructure.

Roadmap Toward a Quantum-Resistant Internet

Google has already begun experimenting with Merkle Tree Certificates using live internet traffic. The company has outlined a multi-phase rollout strategy aimed at gradually introducing the new system.

The plan includes feasibility testing, collaboration with Certificate Transparency log operators and eventually the creation of a quantum-resistant root store for Chrome by late 2027.

According to industry experts, the initiative represents one of the most significant steps taken so far to prepare the web’s trust infrastructure for the coming quantum computing era.