Table of Content

Key Management Interoperability Protocol

Cybersecurity Frameworks

Limitations of Post Quantum Cryptography

Limitations of Post Quantum Cryptography

At present, the most effective strategy to defend against potential quantum attacks involves the creation of more robust quantum-resistant encryption. Among the various approaches currently under development, post quantum cryptography (PQC) emerges as the most favourable prospect. Despite gaining government support due to its cost-effectiveness, numerous PQC methods demonstrate optimal performance only in controlled laboratory settings. When exposed to the unpredictability of real-world environments, these methods may face challenges in proving their resilience. Moreover, while challenging, their deployment is notably less cumbersome than the implementation of Quantum Key Distribution (QKD).

Here are some limitations of post-quantum cryptography that can’t be ignored:

Significantly large Key sizes and Implications on Performance

Quantum-resistant cryptographic systems typically necessitate significantly larger key sizes compared to traditional public-key algorithms. While these larger keys enhance the security of PQC algorithms, they come with notable performance implications. In contrast to conventional public-key cryptosystems, PQC algorithms may incur longer encryption and decryption times. Additionally, the increased key sizes lead to greater storage requirements, heightened memory usage, and increased demand for network bandwidth.

At a smaller scale and with limited data, the performance impact of quantum-resistant cryptography may go unnoticed. However, as the volume of keys transmitted and managed simultaneously increases, the cumulative effect on performance becomes evident.

Aging infrastructures equipped with outdated hardware may struggle to meet the performance demands of PQC, posing challenges for deployment. Particularly, latency-sensitive applications in autonomous vehicles like computer vision systems could be adversely affected. Resource-constrained devices such as smartphones or IoT devices may encounter difficulties running PQC efficiently.

In essence, upgrading infrastructure might be essential for a seamless transition to PQC, despite its software compatibility with various devices. Although implementing PQC involves costs, some algorithms within this framework offer better efficiency, making strategic algorithm selection crucial for safeguarding your infrastructure against quantum threats.

Difficult Encryption and Scalability

Numerous PQC algorithms face challenges in maintaining their resistance to attacks when operating at scale. For instance, lattice-based cryptography, a promising PQC technique, demonstrates good scalability but achieves only average-case hardness. Simply put, average-case hardness implies that lattice-based cryptography can withstand most, though not all, quantum attacks.

It seems that hardness in scalability and encryption are conflicting attributes, creating a trade-off where excellence in one aspect comes at the expense of the other. However, this observation may apply specifically to the currently developing PQC systems. There remains the possibility that, in the future, researchers and cybersecurity providers could devise solutions capable of preserving their hardness across any scale.

Susceptible Progress in Quantum Technology

In contrast to quantum cryptography, particularly quantum key distribution (QKD), quantum-resistant cryptography is susceptible to quantum technology’s growing computational capabilities. QKD, rooted in quantum mechanics, theoretically remains impervious to attacks from quantum computers, irrespective of their computing power, offering a theoretically future-proof security solution. While QKD has practical limitations, it does provide a theoretical avenue for future-proof security.

Conversely, the vulnerability of quantum-resistant cryptography to advancements in quantum technology presents a long-term concern, albeit not an immediate one. Although this issue may not demand immediate attention, it is crucial to bear in mind as technology progresses. With the increasing potency of quantum computers, early Post-Quantum Cryptography (PQC) algorithms might necessitate upgrades or complete replacements.

While extending cryptographic key lengths can partially mitigate escalating quantum power, there remains the possibility that PQC could eventually become vulnerable to highly advanced quantum computers. Additionally, there is the speculative prospect that researchers could devise quantum algorithms capable of effortlessly solving the mathematical foundations of PQC, similar to how Shor’s algorithm disrupted assumptions in classical cryptography.

Trust of Public

A challenge inherent in the introduction of any new technology lies in gaining public acceptance. Despite advancements in quantum key distribution systems and other quantum protocols, concerns about trust, especially within the public sector, continue to impede their widespread adoption. Prospective users and clients seek reassurance from government agencies regarding data encryption security within the devices hosting this innovative form of public key infrastructure (PKI).

Integration Challenges

Transitioning from classical to PQC systems requires careful planning and integration efforts. Existing systems and infrastructure heavily rely on classical cryptographic algorithms. Migrating to new algorithms can involve significant changes to existing code and potentially lead to compatibility issues between different systems.

For example, an organization might rely on a specific classical cryptographic library for data encryption in its applications. Switching to a PQC alternative might require modifying the library integration within the applications, potentially impacting functionality and requiring thorough testing to ensure compatibility and continued security.

Quantum-Safe Protocols

Developing quantum-safe protocols goes beyond simply replacing cryptographic algorithms. It involves rethinking and adapting various aspects of cryptographic systems, including:

  • Key exchange

    This process establishes a shared secret key between two parties for secure communication. PQC needs to ensure key exchange remains secure even against potential quantum attacks.

  • Digital signatures

    These are used to verify the authenticity and integrity of digital documents. PQC needs to ensure signatures remain unforgeable and verifiable even if a quantum computer is involved.

  • Secure communication protocols

    These protocols govern how data is exchanged securely between parties. PQC needs to be integrated into these protocols to maintain confidentiality and integrity of the communication.

Unknown Quantum Computing Timeline

The exact timeframe for the development of practical and powerful quantum computers with the ability to break current cryptographic systems is uncertain. This makes it challenging to prioritize and implement PQC solutions with absolute certainty about the immediate threat. However, it is crucial to be proactive and start preparing for the future by exploring and testing PQC solutions to ensure a smooth transition when the need arises.

By understanding the potential impact of quantum computers and the limitations of PQC, organizations can make informed decisions about their cybersecurity strategy and begin the process of transitioning to quantum-resistant solutions.


While PQC stands out as a promising defense strategy against potential quantum attacks, it is essential to acknowledge its inherent limitations. The substantial key sizes required for enhanced security can lead to significant performance implications, especially in larger-scale implementations where encryption and decryption times may become noticeable.

The challenges in encryption and scalability, exemplified by the trade-off between scalability and encryption hardness in some PQC algorithms, highlight the need for ongoing research and refinement.

Moreover, the susceptibility of quantum-resistant cryptography to progress in quantum technology poses a long-term concern, emphasizing the necessity for continuous advancements and adaptability in the field. As we navigate the complex landscape of quantum threats, strategic algorithm selection, infrastructure upgrades, and a nuanced understanding of these limitations will be crucial in safeguarding against potential risks.

Encryption Consulting’s Post-Quantum Cryptography Advisory Services ensure your organization is compliant with evolving security standards. We’ll help you navigate the complexities of post-quantum cryptography, guaranteeing long-term data protection.

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