Post-quantum certificates: Cloudflare wants to become a certificate authority

Cloudflare announced on September 29, 2026 that it is applying to become a public certificate authority. The company, which carries a significant share of global web traffic, aims in particular to be one of the first to issue post-quantum certificates.

What was announced

• Cloudflare signed a definitive agreement to acquire an established root of trust from GlobalSign, and will also submit a new root to browser programs.
• The company has applied to the root programs of Chrome, Apple, Microsoft and Mozilla.
• Certificates will be issued and renewed automatically via the ACME protocol, the same one used by Let’s Encrypt.
• The first Merkle Tree Certificates are expected in the first quarter of 2027. Cloudflare states that it is not yet issuing certificates.

Why certificates are the sticking point

Post-quantum key exchange is already widely deployed: according to Cloudflare, more than 60% of human-originated TLS traffic to its network was protected by hybrid ML-KEM as of February 2026. Signatures, however, have yet to be migrated. Standardized post-quantum signatures are much larger than current ones, and a TLS connection carries several of them: certificate, chain, transparency proofs. Replacing them as they are would noticeably weigh down every connection.

Merkle Tree Certificates are one answer to this problem: a much more compact certificate format that groups many certificates into a hash tree to limit the number of signatures to transmit. Cloudflare is targeting the quantum-resistant root program announced by Chrome.

What this means for you

In the short term, there is nothing to do: this is an announcement, and browsers still have to adopt the format. But it is a strong signal: the migration of public PKIs is under way. For your internal PKIs, now is the time to assess their ability to handle post-quantum algorithms and larger certificates, and to ask the vendors of your certificate authorities and HSMs about their roadmap.