For decades, computing has been built around the same basic unit: the bit, represented as either 0 or 1. Quantum computing introduces something fundamentally different.
Instead of bits, quantum computers use qubits, which behave according to the laws of quantum mechanics. This could eventually allow computers to tackle certain problems that are extremely difficult for today’s machines.
For the digital economy, however, the significance goes beyond computing power. Quantum technology could affect cybersecurity, financial infrastructure, optimisation and the way sensitive digital information is protected.
So how does quantum computing actually work — and why should businesses and financial institutions care?
From bits to qubits
Traditional computers process information using bits. Everything from a banking transaction to an image or an email is ultimately represented through combinations of 0s and 1s.
Quantum computers use quantum bits, or qubits.
Unlike a classical bit, a qubit can exist in a quantum state involving both 0 and 1 before it is measured. This property is called superposition.
Quantum computing also makes use of entanglement, which allows qubits to develop correlations that cannot be fully described independently, and interference, which quantum algorithms use to increase the probability of useful outcomes while suppressing others.
A simplified way to think about it is:
Superposition creates possibilities → entanglement connects qubits → interference manipulates outcomes → measurement produces a result.
This doesn’t mean quantum computers simply test every possible answer simultaneously. Instead, quantum algorithms are designed to manipulate quantum states so that useful information can emerge when the system is measured.
A different kind of computing
Quantum computers aren’t simply faster versions of conventional computers.
You wouldn’t need one to browse the internet, process payments or run a spreadsheet. Classical computers already perform these tasks extremely well.
The potential advantage lies in specific computational problems that become extremely difficult as their complexity increases.
One important area is simulation. Molecules and materials themselves follow the laws of quantum mechanics, making some complex systems difficult to model accurately using classical machines. More advanced quantum computers could eventually contribute to areas such as chemistry, materials science and drug discovery.
Researchers are also exploring their potential for certain optimisation problems — an area with obvious implications for industries managing highly complex systems.
Why quantum computing matters for finance
Financial institutions process enormous quantities of data and rely on complex computational models.
This has made finance an important area of quantum research.
Potential applications being investigated include portfolio optimisation, risk analysis and complex financial modelling. Quantum approaches may eventually offer advantages for some of these problems, although practical benefits at commercial scale have yet to be established.
For banks and fintech companies, however, the most immediate impact of quantum computing may have less to do with faster calculations and more to do with security.
The cybersecurity problem
Modern digital finance depends on cryptography.
Every time sensitive information is exchanged online — from communications to digital transactions — cryptographic systems help protect that data and verify who is sending it.
The public-key methods that underpin most of today’s secure communications, such as RSA and elliptic-curve cryptography, rely on mathematical problems that are extremely difficult for classical computers to solve.
Quantum computing could change this.
In 1994, mathematician Peter Shor developed an algorithm showing that a sufficiently powerful quantum computer could efficiently solve these mathematical problems. Symmetric encryption such as AES is less exposed: quantum attacks would weaken it, but longer keys are expected to keep it secure.
Machines capable of doing this at a meaningful scale do not currently exist. But the bar is falling: in 2025, a Google researcher estimated that breaking 2048-bit RSA could require fewer than one million physical qubits, down from around 20 million in a 2019 estimate.
Cybersecurity infrastructure can also take years to replace, and information encrypted today may remain sensitive far into the future. Attackers could collect encrypted data now and decrypt it once capable machines exist — a risk known as “harvest now, decrypt later”. For finance, there is a second concern: digital signatures that authenticate transactions and users could eventually be forged.
This has created a new technological challenge: preparing digital infrastructure for a world in which powerful quantum computers might eventually exist.
Enter post-quantum cryptography
The response is post-quantum cryptography (PQC).
Despite its name, PQC doesn’t require a quantum computer. It refers to cryptographic algorithms that run on conventional systems but are designed to withstand attacks from both classical and future quantum computers.
In 2024, the U.S. National Institute of Standards and Technology finalised its first three post-quantum cryptography standards — one for encryption and two for digital signatures — marking an important step towards the migration to quantum-resistant security. In 2025, it selected an additional algorithm, HQC, as a backup.
For financial institutions, governments and technology companies, this means quantum computing is no longer purely a future concern.
Its potential impact is already influencing decisions about today’s digital infrastructure.
Why don’t we have powerful quantum computers yet?
Building them is extraordinarily difficult.
Qubits are highly sensitive to their environment. Noise can disrupt their quantum states and introduce errors into calculations.
Researchers are therefore developing quantum error correction, which uses multiple physical qubits to create more reliable logical qubits.
Different technologies are also competing to build scalable quantum machines, including superconducting circuits, trapped ions, neutral atoms, photons and spin qubits in silicon.
Today’s quantum computers are real, but they remain limited and error-prone. Many of the applications associated with quantum computing would require considerably larger and more reliable systems.
Beyond the hype
Quantum computing sits in an unusual position: the science is established, the machines exist, but many of the commercial applications remain experimental.
For the digital economy, that distinction matters.
Quantum computers are unlikely to replace classical machines. Instead, they could eventually become specialised tools operating alongside existing infrastructure.
Their most important impact may also arrive before the technology reaches its full potential. The transition towards quantum-resistant cybersecurity has already begun.
The question is therefore no longer simply whether quantum computing will become powerful enough to transform certain industries. It is how businesses should prepare for it now.
