Post-Quantum Cryptography in 2025: NIST’s HQC Algorithm and Preparing for the Quantum Threat

Published on June 7, 2025 | Nathirsa Blog

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The rise of quantum computing poses a significant threat to traditional cryptographic algorithms, which secure much of today’s digital communications. In response, the U.S. National Institute of Standards and Technology (NIST) has been leading a global effort to standardize post-quantum cryptography (PQC) algorithms that can resist quantum attacks.

Why Traditional Encryption is at Risk

Algorithms like RSA, DSA, ECDSA, and Diffie-Hellman rely on mathematical problems such as factoring large primes or solving discrete logarithms. Quantum algorithms, notably Shor’s algorithm, can solve these problems efficiently, rendering these cryptosystems vulnerable once sufficiently powerful quantum computers become available.

NIST’s PQC Standardization and the HQC Algorithm

In 2024, NIST finalized several quantum-resistant algorithms, including ML-KEM (formerly CRYSTALS-Kyber), which is based on lattice problems. In March 2025, NIST selected the Hamming Quasi-Cyclic (HQC) algorithm as a backup encryption method. HQC is based on code-based cryptography, leveraging the hardness of decoding random linear codes, a problem believed to be resistant to quantum attacks.

While HQC requires more computational resources than ML-KEM, its distinct mathematical foundation provides cryptographic diversity, essential for a robust defense against future quantum threats.

Preparing for the PQC Transition

Transitioning to PQC is a complex, phased process that involves:

• Inventorying cryptographic assets and identifying vulnerable systems.
• Implementing hybrid cryptographic solutions combining classical and PQC algorithms.
• Testing and validating PQC implementations for performance and interoperability.
• Aligning with regulatory guidance and industry best practices.

Global Developments and Regulatory Landscape

Besides the U.S., countries like China are developing their own quantum-resistant encryption standards, highlighting the global urgency of this transition. Regulatory bodies and governments are urging organizations to act promptly to avoid future data breaches caused by quantum-enabled decryption.

Challenges Ahead

Key challenges include managing the increased computational overhead of PQC algorithms, integrating them into legacy systems, and navigating evolving regulations. Continuous collaboration among academia, industry, and government is critical to address these hurdles effectively.

Recommended Video: Understanding Post-Quantum Cryptography

Conclusion

NIST’s selection of HQC as a backup PQC algorithm reinforces the importance of cryptographic diversity in preparing for the quantum era. Organizations must proactively adopt PQC standards, plan for hybrid deployments, and stay informed on global developments to safeguard their digital assets against the looming quantum threat.

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