Cloudflare is launching a public certificate authority to issue post-quantum Merkle Tree Certificates. This format addresses the large size of standard post-quantum signatures, which can reach 2,420 bytes compared to 64 bytes for current elliptic curve schemes. The company aims to mitigate risks associated with the concentration of certificate issuance among a few dominant providers.
The new authority will allow site owners to manage both conventional and post-quantum certificates through a single system. Cloudflare plans to use RFC 9773 for automated certificate renewal and replacement. To ensure compatibility with legacy hardware, the company intends to acquire an established root certificate already recognized by older devices.
Cloudflare has submitted applications to root programs managed by Apple, Microsoft, Mozilla, and Chrome. The company intends to maintain transparency by publishing reproducible code builds and providing a public health dashboard. While conventional certificate issuance depends on approval from browser root programs, production of Merkle Tree Certificates is set for the first quarter of 2027.
This initiative builds on Cloudflare's Universal SSL program, launched in 2014 to provide free certificates. CEO Matthew Prince identified the transition to post-quantum security as a major internet coordination challenge. The company previously conducted a successful joint experiment with the Google Chrome team and noted that Let's Encrypt plans to support the format in 2027.
