Email security - Post-quantum key exchange for MX deployments

Cloudflare Email Security now supports post-quantum hybrid key exchange with X25519MLKEM768 on the SMTP connections we make to receive and deliver mail. Deploying Email Security in front of a provider that supports post-quantum hybrid key agreement (like Google Workspace) will create a TLS 1.3 connection using post-quantum key agreement. Inbound MX connections and outbound delivery connections now negotiate the X25519MLKEM768 hybrid key agreement when the peer supports it, protecting SMTP traffic against harvest-now, decrypt-later ↗ attacks.