Quantum computing offers both significant risks and advantages. It was initially developed to accelerate progress in fields such as drug discovery, materials science, batteries, superconductors, and fertilisers, and to solve complex problems more efficiently (Bauer et al., 2020, pp. 12685-12717). The primary advantage of quantum computers over classical counterparts lies in their use of quantum phenomena like superposition and entanglement. These principles allow quantum computers to perform numerous calculations simultaneously, thereby solving certain complex problems faster. For instance, a quantum computer can analyse multiple possibilities at once, equipping it with the potential to revolutionise industries far beyond its initial scope of application. However, its potential applications extend further.

Why was the Quantum Computer Created

Quantum computers were created to overcome the limitations of classical computers, which struggle to solve certain complex mathematical problems at scale. As classical systems reached their computational limits, researchers turned to quantum mechanics for alternative solutions. Quantum computers can address problems that are infeasible for classical machines.

How was the Quantum Computer Created

It started as a theory in the 1980s. Classical computers struggle to simulate quantum systems. Using classical bits to model quantum behaviour is inefficient, then Richard Feynman said, “If nature is quantum, then computers should be quantum”.

By the early 1990s, David Deutsch formalised the idea of a universal quantum computer, laying the theoretical foundation for quantum computation. In 1994, Peter Shor introduced an algorithm that demonstrated how quantum computers could factor large numbers exponentially faster than classical systems, while Lov Grover later proposed a quantum search algorithm that offered significant speedups for unstructured data searches. At this point, the computer only existed on paper, and the government quietly started paying attention. (Historical Roots and Seminal Papers of Quantum Technology 2.0, 2022) A quantum computer needs qubits to work, unlike a regular computer, which works on bits. Qubits, the fundamental unit of quantum information, are challenging to create because they require maintaining quantum states that are easily disrupted by environmental factors. This issue persisted into the early 2000s. From the 2010s onward, companies like IBM, Google, Intel, and Microsoft became involved. Universities partnered with governments, and cloud-access quantum computers began to appear.

Quantum Computing Threats towards Cryptography Security

Modern cryptography (how we keep data safe, like banking info, messages, passwords) relies on mathematical problems that classical computers can’t solve easily. Quantum computers, because they use superposition and entanglement, can solve some of these problems much faster. For example, Shor’s algorithm can theoretically reduce the time needed to factor a 2,048-bit RSA key from millennia to mere hours. This acceleration in problem-solving could cut effective key strength in half (AES-128 to AES-64), potentially decrypt emails, digital signatures, and financial transactions, and make some blockchain and password protections easier to attack.

What can be used to Fight Quantum Computing?

Given the imminent threat quantum computing poses to current encryption protocols, the U.S. National Institute of Standards and Technology (NIST) has been developing new encryption standards that can withstand the power of quantum computers.1 In August 2024, NIST announced three post-quantum cryptographic (PQC) standards — CRYSTALS-Kyber, CRYSTALS-Dilithium, and SPHINCS+. These are designed to replace vulnerable algorithms like RSA and Elliptic Curve Cryptography (ECC)

• Longer keys in symmetric encryption:  Symmetric encryption algorithms, such as AES, use the same key for both encryption and decryption. Unlike public-key systems, symmetric encryption is not directly vulnerable to Shor’s algorithm. However, quantum computers can exploit Grover’s algorithm to search the key space more efficiently, effectively reducing the security of the key by half. The primary defence is to increase the key length. For example, upgrading from AES-128 to AES-256 effectively restores security against quantum attacks. Grover’s algorithm provides a quadratic speedup in key search operations. Consequently, AES-128, which normally provides 128-bit security, would be reduced to an effective 64-bit security under a quantum attack. AES-256, by contrast, maintains a robust 128-bit security margin, rendering it resistant to current quantum threats. The approach is straightforward and compatible with existing symmetric encryption systems. Larger key sizes can introduce slight computational overhead, but the increased security justifies the trade-off.
• Quantum key distribution ( QKD): In Quantum Key Distribution (QKD), the sender encodes information into the quantum states of photons. The receiver then measures these photons to retrieve the transmitted key. Any attempt at eavesdropping by a third party inevitably alters the quantum states, immediately alerting Alice and Bob to the intrusion. One of the most widely implemented protocols is BB84, recognised as the first and most prominent QKD protocol. The security of QKD relies on fundamental principles of quantum mechanics, which make it impossible to observe a quantum system without perturbing it. This property enables provably secure key distribution, resistant to both classical and quantum computational attacks. However, QKD does have practical limitations. It requires specialised hardware, including photon emitters and detectors, and is constrained in range due to photon loss over fibre optic cables, typically around 100–200 km without quantum repeaters. While not yet universally practical, QKD offers highly robust security in applications where implementation is feasible.
• Hybrid Approaches: Hybrid Approaches integrate classical encryption with quantum-resistant methods, establishing multiple layers of protection. Data is encrypted using traditional algorithms such as RSA, ECC, or AES, while simultaneously employing a post-quantum cryptographic algorithm or Quantum Key Distribution (QKD) to secure the encryption keys. This layered approach ensures that even if a quantum computer compromises one layer, the remaining protections continue to safeguard the data. Hybrid systems provide both immediate security and future-proofing. Since quantum computers capable of breaking current encryption standards may not be available for several years, combining classical and quantum-resistant methods allows organisations to protect sensitive information today while preparing for future threats. Implementing hybrid approaches introduces greater complexity, may increase computational and network overhead, and requires meticulous key management to maintain overall security integrity.

Preparing for the Quantum Era

Quantum computing represents both a revolutionary tool and a significant challenge. While originally developed to accelerate scientific discovery in areas such as drug development, materials science, and complex problem-solving, its unique capabilities also pose a direct threat to current cryptographic systems. By leveraging superposition and entanglement, quantum computers can solve certain mathematical problems far more efficiently than classical machines, putting widely used encryption methods at risk.

Fortunately, a variety of strategies exist to safeguard digital security against this emerging threat. Post-quantum cryptography offers algorithms specifically designed to resist quantum attacks, while longer symmetric keys, quantum key distribution (QKD), and hybrid approaches provide layered protection against potential breaches. These solutions enable organisations to maintain the confidentiality and integrity of sensitive information, even as quantum technologies continue to advance.

Ultimately, the rise of quantum computing underscores the need for proactive adaptation in cybersecurity. By embracing quantum-resistant technologies today, institutions can both protect their data in the present and prepare for the inevitable future where quantum computers become more powerful and accessible. The balance between innovation and security will define the next era of digital resilience.

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