Post-Quantum Cryptography: Securing Infrastructure Against Tomorrow’s Threats

Today’s internet security relies almost entirely on the difficulty of factoring large numbers into prime factors (RSA) or computing discrete logarithms on elliptic curves (ECC). A sufficiently powerful quantum computer uses the Shor algorithm to solve these problems trivially.

The problem for companies today is: “Harvest Now, Decrypt Later”. Attackers are storing encrypted data streams today to decrypt them in 5 to 10 years using quantum computers. Anyone transmitting sensitive data (patient records, state secrets, IP) today must switch to quantum-safe methods now.

The Technical Core: New Mathematical Problems

PQC is based on mathematical problems that are believed to be extremely difficult for quantum computers to solve. The leading approaches currently being standardized by NIST (National Institute of Standards and Technology) are:

1. Lattice-based Cryptography: Based on the “Learning With Errors” (LWE) problem in high-dimensional lattices. The most important representative is ML-KEM (formerly Kyber) for key exchange.
2. Hash-based Signatures: Methods like SLH-DSA (Sphinx+), which rely solely on the security of cryptographic hash functions.
3. Code-based Cryptography: Utilizes error-correcting codes (e.g., McEliece scheme), which require very large public keys but are considered extremely secure.

The Challenge for IT Infrastructure

Switching to PQC is not a simple software update. It brings significant technical challenges to the architecture:

1. Larger Keys and Signatures

PQC algorithms generate significantly larger keys and signatures than ECC or RSA.

• Impact: A TLS handshake with PQC requires more packets. This can lead to issues with unstable connections or devices with a small MTU (Maximum Transmission Unit) value. Load balancers and firewalls must be prepared to handle these larger packets.

2. Higher Computational Load

The computation of lattice-based algorithms is more resource-intensive.

• Impact: The CPU load at endpoints (edge gateways, load balancers) increases. Infrastructure teams must reassess the capacity of their TLS termination and possibly rely on hardware acceleration (special NPUs or FPGAs).

3. Hybrid Key Exchange Methods

Since PQC algorithms are relatively new, they are not yet blindly trusted. The current standard for the transition period is the hybrid mode.

• Technique: A classical key (e.g., X25519) is combined with a PQC key (e.g., Kyber/ML-KEM). An attacker would have to break both methods to access the data.
• Infrastructure Task: Implementing TLS 1.3 with hybrid key exchange groups throughout the service mesh architecture (e.g., via Envoy or Istio).

Implementation Steps in the Cloud-Native World

How does ayedo specifically prepare a Kubernetes infrastructure for PQC?

1. Inventory & Crypto-Agility: First, we identify all points where encryption occurs (ingress, inter-pod communication, VPNs, database encryption). The goal is “crypto-agility” – the ability to swap algorithms via configuration without changing the code.
2. Update of TLS Stacks: Migration to libraries like BoringSSL or OpenSSL 3.x, which already support initial PQC implementations (e.g., via OQS-Provider).
3. Certificate Management: Transition of the PKI (Public Key Infrastructure) to quantum-safe signatures. Tools like cert-manager in Kubernetes must be prepared to sign and rotate certificates with new algorithms.

FAQ: Post-Quantum Cryptography

When will RSA/ECC become concretely worthless? Estimates suggest that a quantum computer with about 20 million qubits (error-corrected) could break RSA-2048. Experts expect this point between 2030 and 2035. Since infrastructure cycles often last 5-10 years, planning today is imperative.

Why are lattice-based methods (Lattices) the favorite? They offer the best balance between security, key size, and computation time. ML-KEM (Kyber) is, for example, performant enough to be used in web browsers and on servers without massive delay.

Are there hardware accelerators for PQC? Yes, initial providers are integrating PQC acceleration into their SmartNICs and HSMs (Hardware Security Modules). In a modern infrastructure, the offloading strategy for PQC traffic will be a central architectural theme.

What happens to existing VPN tunnels? Protocols like WireGuard or IPsec must be updated to PQC-compliant versions. For WireGuard, there are already experimental implementations (“Rosenpass”) that use a hybrid PQC key exchange.

Is Blockchain affected by PQC? Massively. Most blockchains are based on ECDSA (Elliptic Curve Digital Signature Algorithm). Without a hard fork to PQC signatures, quantum computers could potentially empty foreign wallets by calculating the private key from the public key.