State of the post-quantum Internet in 2025

Cloudflare reports that in the last week of October 2025 the majority of human-initiated Internet traffic is protected by post-quantum encryption, mitigating harvest-now/decrypt-later threats. The post-quantum migration is described as consisting of two migrations: key agreement and signatures/certificates, with the former already widely deployed across clients and servers.

Today, most clients use X25519MLKEM768 for post-quantum key agreement, and over 50% of human traffic is protected by this post-quantum key agreement, rising steadily. Server-side support grew to about 39% for origins by September 2025, with 3.7% of origins applying the post-quantum key agreement.

The piece also covers NIST standardisation progress, noting ML-KEM as the standard for key agreement and three signatures schemes standardised in 2024, while highlighting ongoing debates and timelines for post-quantum certificates and hybrid deployments. It emphasises that while the migration is underway, the final post-quantum authentication remains slower to deploy and may require further innovations such as Merkle Tree Certificates.