After using several post-quantum secure VPN tunnels (here and there), I was interested in how this key exchange with ML-KEM looks on the wire. Especially in direct comparison to a classical VPN setup with just ECDH (group 21). Spoiler: since it does not fit in a single packet, it has to use a new form of fragmentation. 😳 Here we go:
Continue reading Packet Capture of a Post-Quantum Site-to-Site VPN
Since we have learned the basics of post-quantum secure VPN tunnels, let’s configure a site-to-site VPN between a Palo Alto Networks firewall and a FortiGate with PQC ciphers to verify vendor interoperability. Spoiler: it works like a charm. ;)
Continue reading PQC VPN-Tunnel between Palo Alto <-> FortiGate
As the advent of practical quantum computing draws closer, security vendors are increasingly introducing post-quantum cryptographic (PQC) algorithms to protect existing security architectures against future threats. One important use case is site-to-site VPN connectivity, where organisations must address the “harvest now, decrypt later” risk – the possibility that encrypted traffic captured today could be decrypted by quantum computers in the future.
To mitigate this threat, Palo Alto Networks has implemented several approaches for quantum-resistant VPN tunnels, including Post-Quantum Preshared Keys (PPK), Key Encapsulation Mechanisms (KEM), and Quantum Key Distribution (QKD). Each method offers a different balance of security, complexity, and operational requirements.
In this blog post, we will examine these approaches in detail, with a particular focus on KEM-based solutions, which are generally considered the preferred path forward. We will also demonstrate how to configure a site-to-site VPN tunnel that combines traditional Diffie-Hellman (DH) key exchange with post-quantum algorithms such as Kyber (standardised by NIST as ML-KEM), providing both classical and quantum-resistant security.