Why Post-Quantum Crypto Must Be a Baseline, Not a Premium

Cloudflare has announced that its implementations of post-quantum cryptography (PQC) will be available to everyone, free of charge, forever. The decision follows the company's earlier move in 2014 to make SSL free for all customers under Universal SSL, a step taken even at the cost of revenue because encrypted-by-default was deemed essential to the Internet's future.

"Every byte, however seemingly mundane, that flows encrypted across the Internet makes it more difficult for those who wish to intercept, throttle, or censor the web... Together we can do great things."

The rationale for free PQC mirrors that earlier logic: privacy is a human right, and the most advanced cryptography must be accessible to all. Cloudflare is also urging other vendors to make their PQC implementations free, so that the Internet does not acquire a "quantum" up-charge.

Preparing for a Known, Undated Threat

The push for PQC is driven by a thesis similar to the Year 2000 problem: quantum computers that can break conventional cryptography are a known future threat, but unlike Y2K, the exact date of the break is unknown. Preparation must therefore begin now. Cloudflare has been working on this transition since 2018, following concerns about the implementation problems that the move to TLS 1.3 caused for customers.

Since then, Cloudflare Research has collaborated with Google and Mozilla, contributed to IETF work on standards, and launched the experimental open-source cryptography suite CIRCL. The company has been vocal in its criticism of vendors attempting to commercialize vague "post-quantum" solutions based on non-standard algorithms or unproven technologies like Quantum Key Distribution — offerings that often come with high price tags but little public review or demonstrated functionality.

Testing PQC in Your Network Today

For current traffic, Cloudflare supports Kyber for key agreement on any TLS 1.3 connection, including HTTP/3. To help users test these key agreement methods, the company has open-sourced forks for BoringSSL, Go, and quic-go.

For those using cloudflared with Tunnels, upgrading is straightforward: ensure version 2022.9.1 or later is installed, then run cloudflared --post-quantum.

Before rolling out PQC internally, the first step is inventory and identification of all systems — a process Cloudflare knows well from its FedRAMP Authorization evaluations, and one it is repeating for the internal transition to PQC.

Securing Internal Systems, Zero Trust, and Open Source

Cloudflare's own path to full PQC adoption in 2023 spans three areas: internal connections, zero trust products, and open source contributions.

Internal Connections

The first area concerns the connections inside Cloudflare's own infrastructure. BoringSSL is used for many of these connections, and upstream support for Kyber is already underway. Any internal connections using different cryptographic systems are also being upgraded. The remaining internal connections that rely on TLS 1.2 are being shifted to TLS 1.3. Combining Kyber with TLS 1.3 makes internal connections both faster and more secure, even with the hybrid classical/post-quantum approach — a combination Cloudflare says it proved effective over three and a half years ago in work with Google.

Zero Trust Alignment

The second area addresses the zero trust paradigm. Cloudflare argues that many zero trust vendor products fail to support common protocols like IPv6 and TLS 1.2, let alone TLS 1.3 and QUIC, which enable PQC. Such middleboxes often break user security connections by artificially downgrading them during inspection. Cloudflare is evaluating upgrades so its zero trust products support PQC out of the box, treating zero trust and post-quantum cryptography not as competing priorities but as complementary components of the future security standard.

Open-Source Contributions

The third area focuses on open source. CIRCL, Cloudflare's Go-based collection of cryptographic primitives for experimental post-quantum deployments, continues to receive release attention. Later this year, Cloudflare will publish vendor-neutral, easy-to-adopt roadmaps as open source to help organizations upgrade their own systems. Supporting resources include documentation on turning on PQC today, post-quantum Cloudflare Tunnel, NIST's post-quantum standardization developments, and internal service upgrades for logfwrdr, Tunnel, and gokeyless.