Cloudflare now uses post-quantum cryptography to talk to your origin server

What this post added

This post details the rollout of X25519+Kyber for outbound connections from Cloudflare to origin servers and Cloudflare Workers fetch() calls. It explains the TLS 1.3 handshake, the role of HelloRetryRequest, and the hybrid nature of X25519+Kyber, which combines X25519 with a preliminary version of NIST's Kyber. The post also outlines the phased rollout plan for different Cloudflare plans and provides quick start instructions for enabling the feature, including API calls and Nginx configuration examples. It also mentions the future adoption of the ML-KEM standard.