The state of the post-quantum Internet

This post provides an update on the state of post-quantum cryptography (PQC) adoption and its implications for the internet. It highlights that nearly 2% of Cloudflare's TLS 1.3 connections are already secured with PQC, with expectations of double-digit adoption by the end of 2024. The post details the quantum threat, discusses timelines for cryptographically relevant quantum computers, and emphasizes the two main migration paths: key agreement and signatures/certificates. It clarifies that symmetric cryptography is already post-quantum secure and explains the NIST PQC security levels. The post also touches on the challenges of deploying post-quantum signatures at scale and the importance of proactive migration due to the 'harvest now, decrypt later' threat.