A metamorphosis continues to take shape with the rise of Post-Quantum Cryptography, Quantum Key Distribution, and the brave new world of Quantum Networking.

In the ever-evolving landscape of technology, quantum computing stands out as a beacon of both promise and challenge. As we delve into the world of quantum networking and security, we find ourselves at the intersection of groundbreaking innovation and urgent necessity.

Cisco believes that quantum networking is not just an intriguing concept. It drives our research and investment strategy around quantum computing. We see it as a critical path forward because it holds the key to horizontally scaling systems, including quantum computing systems. Imagine a future where quantum computers collaborate seamlessly across vast distances, solving complex problems that were previously insurmountable.

However, before we can realize the promise of quantum networking, we need to address the elephant in the room – security. When quantum computers become reality, our classical cryptographic methods will face an existential threat. These powerful machines will potentially break today’s encryption algorithms in seconds. Our digital fortresses are vulnerable.

This opens the question of what will happen when quantum computers enter the scene. The issue lies in key exchanges. In classical systems, we rely on public key infrastructure (PKI) to securely exchange keys. This has served us well, ensuring confidentiality and integrity. But quantum computers, with their uncanny ability to factor large numbers efficiently, disrupt this equilibrium. Suddenly, our once-secure secrets hang in the balance.

Getting to the heart of the matter, imagine a scenario that persists even in our current era – the ominous concept of “store now, decrypt later”. Picture an adversary intercepting encrypted data today. Biding their time, they await the moment when quantum supremacy becomes reality.

When that day dawns, they unleash their quantum beast upon the stored information. Our sensitive communications, financial transactions, and personal data will suddenly be laid bare, retroactively vulnerable to the quantum onslaught.

Post-Quantum Cryptography is gaining momentum

Enter Post-Quantum Cryptography (PQC). Recognizing the urgency of the coming quantum moment, the National Institute of Standards and Technology (NIST) has been evaluating PQC proposals and is expected to release its final standards for quantum-resistant cryptographic algorithms later this year. These algorithms are designed to withstand quantum attacks and while not perfect, they are intended to fill the gap until quantum-safe solutions mature.

Apple’s iMessage is a compelling proof point. Last year, Apple made a decisive move by announcing its adoption of PQC algorithms for end-to-end encryption. This strategic shift underscores the industry’s recognition of the looming quantum threat, especially around “store now, decrypt later” attacks, and the need to swiftly respond.

In the year ahead, as we move closer to the post-quantum world, PQC will continue to gain momentum as a data security solution. Cisco’s Liz Centoni shared insight in her tech predictions for 2024, highlighting the accelerating adoption of PQC as a software-based approach that works with conventional systems to protect data from future quantum attacks.

PQC will be used by browsers, operating systems, and libraries, and innovators will experiment with integrating it into protocols such as SSL/TLS 1.3, which governs classic cryptography. PQC will likely find its way into enterprises of every size and sector as they seek to safeguard their sensitive data from the threats posed by quantum computers.

Quantum Key Distribution is the holy grail

Beyond PQC lies the holy grail of quantum cryptography, which is Quantum Key Distribution (QKD). Last year, we accurately predicted that QKD would become more widely used, particularly within cloud computing, data centers, autonomous vehicles, and consumer devices like smartphones.

Unlike classical key exchange methods, QKD capitalizes on the no-cloning property inherent in quantum states whereby information encoded on one qubit cannot be copied or duplicated to another because quantum states are fragile, affected by any and every action such as measuring the state. In practical terms, that means an eavesdropper can always be discovered due to a “read” causing the photon state to change.

Consider a scenario where two parties, Bank A and Bank B, want to communicate securely. They use QKD, where Bank A sends quantum states (like polarized photons) to Bank B which measures them without knowing the original state.

The measurements are then used to create a shared key, based on a randomly selected subset of the transmitted state (measurement bases) reconciled between the two parties through an authenticated and encrypted classical channel. Since the eavesdropper does not know the random subset, any attempt to measure the transmitted information will be detected due to a disturbance in the quantum states.

The beauty lies in the provably secure nature of QKD — quantum mechanics forbids perfect cloning, rendering interception futile. In this dance of particles and principles, QKD stands as a lighthouse of security, promising a future where quantum and classical work in tandem to safeguard us.

For instance, integrating QKD in 5G communication infrastructure is becoming increasingly important. With QKD, organizations will be able to better protect the privacy and authenticity of data transmitted over low-latency, high-speed networks, explicitly addressing the security demands of the 5G era.

Efforts to make QKD solutions more accessible and interoperable are accelerating in response to the demand for even more secure data transfer. This is leading to commercialization and standardization initiatives that are expected to make QKD solutions more user friendly and cost effective, ultimately driving widespread adoption across new applications and sectors.

As strides continue toward achieving quantum-secure messaging, among the first organizations to more broadly implement PQC will likely be those responsible for critical infrastructure and essential government suppliers. Large enterprises and other organizations will follow, also implementing these algorithms within the next few years.

Quantum networking on the horizon

Depending on the desired level of security and performance required, Centoni explained that QKD can be used as either an alternative or a complement to PQC and, in the future, will also leverage quantum networking. However, she acknowledges that it’s early days for quantum networks.

So far, researchers have not successfully achieved sustained quantum networking on a large scale, but major discoveries and advancements are happening. Companies like Cisco, alongside cutting-edge leaders across various industries, are pouring billions into unlocking the awesome potential of quantum networks.

“Quantum networking will see significant new research and investment by government and financial services,” said Centoni. She predicts that this will also include sectors with high demand for data security and the kinds of workloads that perform well with quantum computers.

Quantum networking relies on teleportation principles of quantum mechanics to transmit information between two or more quantum computers. This takes place by manipulating qubits whereby they “entangle” with one another and enable instantaneous transfer of quantum information across vast distances – even when there’s no physical connection between the computers.

In the not-so-distant future, perhaps 4 to 5 years or more, quantum networking will inexorably emerge as a potent force. With quantum networking, quantum computers will be able to collaborate and exchange information to tackle intricate problems that no single quantum computer could solve on its own.

By leveraging the quantum principles of teleportation and non-cloning, quantum networking protocols will facilitate fast, reliable – and perhaps even unconditional – secure information exchange. Potential applications of quantum networking go far beyond cryptography, as well, to turbocharging drug discovery, artificial intelligence (AI), and materials science.

Looking to the post-quantum future

Today, quantum computers are at a very similar stage that mainframes were in the 1960s. Back then, very few organizations could afford those machines, which could fill an entire room. While QKD is now in use as a means of provably secure communication, quantum networking remains mainly theoretical.

QKD is the next generation of quantum cryptography, a step beyond PQC which is not provably secure because of the lack of a proof of mathematical hardness for the cryptographic algorithms. Quantum networking should be thought of as first, a substrate needed for QKD, and then building out larger and larger compute islands – such as data centers and LAN, then WAN – analogous to how classical computers were connected to build distributed computing.

The big challenge now, like the past, is to create quantum computers that can be both reliably and affordably scaled up and put into the hands of corporate, government, and research entities. As such, distributed quantum computing will be the primary driver for quantum networks. We may even see the advent of the quantum cloud and the quantum internet – the metamorphic network of the future.

Quantum networking and security are not mere buzzwords. They are our lifelines in a quantum-powered future. As we race against time, we must embrace quantum technologies while fortifying our defenses. The ultimate payoff is a network that’s more secure than anything we’ve known before — a network where quantum and classical dance harmoniously, protecting our digital existence.


With AI as both catalyst and canvas for innovation, this is one of a series of blogs exploring Cisco Executive Vice President Liz Centoni’s tech predictions for 2024. Her complete tech trend predictions can be found in The Year of AI Readiness, Adoption and Tech Integration ebook.

Catch the other blogs in the 2024 Tech Trends series



Vijoy Pandey

Senior Vice President

Outshift by Cisco