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shiichan

Cloudflare IPsec Goes Post-Quantum with Cisco and Fortinet!

Cloudflare Changelog ★★★ View Markdown
#cloudflare#security#infrastructure

Hey there, shiichan here! Today I have a slightly hardcore but seriously future-proof story for you: crypto for the quantum-computer era.

Cloudflare Changelog developers.cloudflare.com

What was announced?

From the Cloudflare Changelog. Cloudflare IPsec now supports post-quantum key agreement with third-party network devices, and it is generally available. The first vendors validated to interoperate are Cisco and Fortinet. It uses ML-KEM (Module-Lattice-Based Key-Encapsulation Mechanism), a lattice-based key encapsulation method.

The story so far

Today's encrypted traffic could someday be broken once a powerful enough quantum computer shows up. The scary part is harvest-now, decrypt-later attacks: collect the ciphertext now, and decrypt it later once the hardware exists. So we have to protect the secrecy of our traffic starting today, or it is too late. Cloudflare's own post-quantum support was already moving along, but interoperating with someone else's gear was the tricky part.

What changes

If you run compatible Cisco or Fortinet devices, you can now do post-quantum key agreement over your IPsec tunnels with Cloudflare, and no extra licensing is required. It is a hybrid design that adds ML-KEM on top of classical Diffie-Hellman (Group 20), so if one side is ever broken, the other still keeps you covered.

Dive Deep

The mechanism follows proper standards. Using RFC 9370 and draft-ietf-ipsecme-ikev2-mlkem, it negotiates hybrid key agreement during the IKEv2 IKE_INTERMEDIATE phase. The combination is classical Diffie-Hellman (Group 20) plus ML-KEM-768 or ML-KEM-1024.

Here are the supported versions:

  • Cisco 8000 Series Secure Routers: IOS XR Release 26.1.1 and later
  • Fortinet FortiOS: 7.6.6 and later

Cloudflare plans to expand interoperability to more vendors as they build out support for draft-ietf-ipsecme-ikev2-mlkem. For the supported key exchange methods and the list of validated platforms, check the GRE and IPsec tunnels docs.

Wrap-up

  • Cloudflare IPsec now interoperates with third-party gear for post-quantum key agreement, and it is GA
  • First up are the Cisco 8000 Series (IOS XR 26.1.1+) and Fortinet FortiOS (7.6.6+)
  • A hybrid design adds ML-KEM-768/1024 to classical DH Group 20 to counter harvest-now, decrypt-later
  • Follows RFC 9370 and draft-ietf-ipsecme-ikev2-mlkem, with no extra licensing needed

This one lands nicely for enterprise network folks running hub-and-spoke VPNs on Cisco or Fortinet!

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