Securing Systems Against Quantum Threats

Written By:
Founder & CTO
June 21, 2025

The advent of quantum computing represents one of the most profound shifts in the landscape of modern technology and cybersecurity. As quantum capabilities mature, they threaten to unravel the foundational principles of today's public-key cryptography, algorithms we’ve trusted for decades, such as RSA and ECC (Elliptic Curve Cryptography). For developers, security architects, and software engineers, this isn’t a theoretical future, it’s an active challenge. Post-Quantum Cryptography (PQC) is the new frontier that aims to secure our digital world from the looming threats posed by quantum advancements.

This blog is your comprehensive guide to understanding, preparing for, and implementing post-quantum cryptographic solutions, particularly tailored for developers who are tasked with securing codebases, communication protocols, and infrastructure components.

What is Post-Quantum Cryptography?

Post-Quantum Cryptography refers to cryptographic algorithms that are designed to be secure against the cryptanalytic capabilities of quantum computers. Quantum computers, leveraging principles such as quantum superposition and entanglement, can execute certain mathematical problems significantly faster than classical computers.

The primary threat arises from Shor’s algorithm, which allows quantum computers to solve the prime factorization problem in polynomial time. This capability directly undermines RSA, Diffie-Hellman, and ECC, all staples of internet security today. A powerful enough quantum computer would be able to crack these within minutes.

PQC doesn’t rely on hard problems like factoring or discrete logs. Instead, it turns to alternatives such as lattice-based cryptography, hash-based signatures, code-based cryptography, multivariate polynomial problems, and supersingular isogeny graphs, each promising resilience against quantum attacks. The aim is not just theoretical resistance but practical integration into existing systems.

In 2022 and 2024, NIST (National Institute of Standards and Technology) finalized and standardized several quantum-safe algorithms:

  • CRYSTALS-Kyber for public key encryption and key encapsulation.

  • CRYSTALS-Dilithium for digital signatures.

  • SPHINCS+, a stateless hash-based signature scheme.

  • HQC as a backup Key Encapsulation Mechanism (KEM) based on code-based cryptography.

This standardization is the foundation of tomorrow’s encryption systems. But implementation begins today.

Why Developers Must Act Now
The "Harvest Now, Decrypt Later" Problem

One of the most urgent concerns is the harvest now, decrypt later attack model. Adversaries can capture encrypted data today, even if they can’t break it yet, and simply wait until quantum technology matures. If that data includes confidential information, intellectual property, or critical communications, it will be exposed retroactively. For developers and teams building secure communication protocols, authentication systems, or cloud services, this is an irreversible security debt.

Post-Quantum Cryptography mitigates this risk by future-proofing encryption, ensuring that even if someone captures the encrypted content now, it remains indecipherable, even when they gain access to quantum computers years later.

Benefits of Post-Quantum Cryptography for Developers

Post-Quantum Cryptography is not just about compliance or futuristic tech, there are direct, practical advantages for developers building software today.

1. Forward Security and Long-Term Data Protection

PQC enhances long-term confidentiality. By using quantum-resistant algorithms, developers can ensure that data remains protected indefinitely, rather than depending on the assumption that quantum machines won’t arrive for decades. Think about legal documents, health records, strategic plans, or industrial blueprints that need confidentiality for 30+ years. PQC gives developers tools to encrypt these assets without fear of future decryption.

2. Compatibility with Modern Cryptographic Systems

PQC algorithms like CRYSTALS-Kyber and Dilithium integrate smoothly with modern protocols. Developers don't need to rebuild entire infrastructures. Many post-quantum primitives can be incorporated into existing frameworks like:

  • TLS (Transport Layer Security): Through hybrid modes that combine ECC and Kyber.

  • Secure messaging protocols like Signal's PQXDH (post-quantum X3DH).

  • Code signing mechanisms in CI/CD pipelines.

  • Software package managers and digital trust chains.

This allows incremental upgrades, easing the migration path while maintaining backward compatibility.

3. Hybrid Encryption Modes for Seamless Transition

Developers can start integrating hybrid cryptographic systems where classical algorithms are paired with post-quantum alternatives. For example, a system might use both ECC and Kyber in key exchange. If one of the algorithms is compromised (e.g., ECC by a quantum machine), the other still provides security.

This hybrid approach is already in use by major organizations:

  • Google’s Chrome has deployed post-quantum hybrid key exchanges in experimental modes.

  • Apple’s iMessage now includes PQ3, combining Kyber and ECC.

  • Cloudflare has implemented PQC in its TLS stack and DNS infrastructure.

These hybrid models allow developers to make quantum resilience part of everyday software, not a radical shift.

4. Cryptographic Diversity Reduces Risk

Traditional cryptography relies heavily on a small number of problems, primarily factoring and elliptic curve mathematics. Post-Quantum Cryptography introduces cryptographic diversity, offering multiple classes of problems that quantum computers can't solve efficiently, yet. This includes:

  • Lattice-based schemes (e.g., Kyber, Dilithium)

  • Hash-based signatures (e.g., SPHINCS+)

  • Code-based encryption (e.g., HQC)

By integrating a range of post-quantum algorithms, developers can mitigate the risk of a single breakthrough collapsing the entire security model.

5. Efficient Performance and Scaling

While PQC algorithms often have larger key sizes and signature lengths, their computation performance is often on par, or even better, than RSA or ECC in practice.

  • Kyber is faster than RSA-2048 for key encapsulation, especially when AVX2 or ARM hardware acceleration is enabled.

  • Dilithium provides efficient signature verification and is suitable for server-side loads where millions of validations may occur.

  • SPHINCS+, although slower, is stateless and great for systems needing maximum security without key management complexities.

For developers working on performance-sensitive systems (like embedded devices or low-latency APIs), choosing the right PQC algorithm can provide both security and speed.

A Step-by-Step Roadmap for Developers to Adopt PQC

Moving to post-quantum cryptography may seem daunting. Here’s how to approach it in a structured, developer-friendly way:

Step 1: Audit and Inventory Current Cryptographic Usage

Start by identifying every instance of cryptographic operations in your system. This includes:

  • HTTPS/TLS certificate generation and validation

  • SSH key exchange

  • Code signing and software verification

  • JWT tokens and message signing

  • VPNs and encrypted tunnels

  • Client libraries with baked-in RSA or ECC defaults

Use tools to scan dependencies and identify embedded cryptographic operations in open-source packages.

Step 2: Prototype Post-Quantum Algorithms

Use libraries like:

  • liboqs (Open Quantum Safe)

  • OpenSSL 3.0+ with PQC patches

  • BoringSSL (experimental Kyber integration)

Set up test cases for key exchange, signature generation, and verification using Kyber and Dilithium. Evaluate the binary size, connection latency, and CPU load.

Step 3: Implement Hybrid Encryption in Critical Paths

Wrap both ECC and Kyber together in your TLS handshake or key exchange layer. This ensures compatibility and buys time to evaluate PQC independently.

Test your hybrid implementation with real clients, validate performance impacts, and gradually expand to other subsystems.

Step 4: Enable Cryptographic Agility

Use abstraction layers that allow easy switching of cryptographic algorithms. For example, don’t hardcode rsa.encrypt(), create cryptoAdapter.encrypt() and let its implementation change based on environment config.

This allows future updates (e.g., from Kyber to HQC) without needing to touch business logic.

Step 5: Monitor Standards and Regulatory Guidelines
  • Follow NIST PQC announcements.

  • Track CISA and ENISA recommendations.

  • Watch for IETF drafts for PQC TLS and SSH integrations.

Also, consider what national security mandates may affect your deployments, especially if working in healthcare, fintech, or government software.

Real-World Examples of PQC Adoption
  • Apple’s iMessage uses PQ3, combining Kyber and ECC for end-to-end encrypted messaging.

  • Signal rolled out PQXDH in 2023, offering quantum-resistant session keys.

  • Google Chrome deployed CECPQ2, a hybrid key exchange using Kyber and X25519.

  • Cloudflare updated its global CDN with hybrid TLS key exchanges and supports post-quantum DNS.

These examples show that PQC is already battle-tested. As a developer, you’re not experimenting in isolation, you’re joining an evolving ecosystem.

Planning Your Post-Quantum Journey: A Strategic Timeline
0–6 Months
  • Start internal testing of PQC libraries.

  • Audit systems and list quantum-vulnerable components.

  • Train development teams on PQC standards and tools.

6–18 Months
  • Roll out PQC in internal tooling.

  • Enable hybrid encryption for HTTPS/TLS and APIs.

  • Sign all test builds and release artifacts with Dilithium.

18+ Months
  • Move production systems to fully PQC-secured connections.

  • Replace legacy signatures in all long-term documents.

  • Maintain PQC versioning and agility across your stack.

Common Challenges and How to Mitigate Them
Larger Key and Signature Sizes

PQC schemes like Dilithium and Kyber produce larger keys and ciphertexts compared to ECC or RSA. But compression, streaming APIs, and CDN caching mitigate most of this.

Performance Overhead

Performance hits are minimal on modern hardware, especially with SIMD instructions (AVX2 on Intel, NEON on ARM). Parallelize operations where possible and benchmark using profiling tools.

Interoperability Issues

Use hybrid modes initially. Implement feature flags to allow PQC to run only between compatible systems.

Algorithm Evolution

The cryptographic landscape may shift again. Prioritize modular code design. Keep signing and key exchange logic abstracted from core business functions.

Future-Proofing Begins Today

Post-Quantum Cryptography isn’t just a cryptographic challenge, it’s a software engineering problem. Developers must prepare now. Start by evaluating your systems, integrating hybrid cryptography, and enabling agility in how encryption is implemented across products. By transitioning early, you future-proof your applications, ensure long-term trust, and stay ahead of regulatory timelines.

The quantum era is coming, are your systems ready?