Post-quantum IPsec interoperability with third-party devices

Cloudflare IPsec now supports post-quantum key agreement with compatible third-party devices. Cisco and Fortinet are the first third-party vendors validated to interoperate with Cloudflare IPsec using ML-KEM (Module-Lattice-Based Key-Encapsulation Mechanism).

Post-quantum IPsec uses RFC 9370 and draft-ietf-ipsecme-ikev2-mlkem to negotiate hybrid key agreement during the IKEv2 IKE_INTERMEDIATE phase. This combines classical Diffie-Hellman (Group 20) with ML-KEM-768 or ML-KEM-1024 to protect against harvest-now, decrypt-later attacks.

Key details:

• Compatible with Cisco 8000 Series Secure Routers with IOS XR Release 26.1.1 and Fortinet FortiOS 7.6.6 and later.
• Uses ML-KEM-768 or ML-KEM-1024 as an additional Key Exchange to DH Group 20.
• Follows RFC 9370 and draft-ietf-ipsecme-ikev2-mlkem standards.
• No additional licensing required.

Post-quantum IPsec with third-party devices is now generally available with confirmed interoperability for the platforms listed above. Cloudflare intends to support interoperability with more vendors as they build out support for draft-ietf-ipsecme-ikev2-mlkem. Contact your account team to discuss support for additional vendors.

For supported key exchange methods and the list of validated platforms, refer to GRE and IPsec tunnels.