Quantum Computing Explained Without the Jargon
Quantum computers use the odd rules of tiny particles to solve certain problems in new ways. Learn the basics, what they cannot do, and why banks are already preparing for them.
You have probably read that quantum computers will change everything. The reality is more interesting and more limited. Here is a clear picture, without the maths.
Bits and qubits
A normal computer stores information in bits, each either 0 or 1, like a switch that is off or on. A quantum computer uses qubits. Thanks to quantum physics, a qubit can be in a blend of 0 and 1 at the same time. This is called superposition. Qubits can also be linked so that they share information in ways ordinary bits cannot, which is called entanglement.
What they may be good at
- Simulating molecules and materials, which could help discover new medicines or batteries.
- Certain optimisation problems, such as complex scheduling or logistics.
- Breaking some of today's encryption, which is the part that worries security experts.
What they will not do
- They will not replace your phone or laptop.
- They are not faster at everyday tasks like browsing or watching video.
- They are not ready to solve every problem today. Qubits are fragile and easily disturbed, so machines make errors and need extensive error correction.
Why this matters for security
Much of today's internet security, including the locks that protect online banking, relies on maths problems that are very hard for normal computers. A large, reliable quantum computer could solve some of them quickly. Such a machine does not exist yet, but criminals and governments could be collecting encrypted data now, to unlock it later. This is called "harvest now, decrypt later".
What is being done
In August 2024, the US National Institute of Standards and Technology (NIST) published its first three post-quantum cryptography standards. These are new encryption methods designed to resist attacks from both normal and quantum computers. Banks, browsers, and governments are now planning a long transition to them.
What you can do today
Keep devices and apps updated
Updates will bring in new protections as they are rolled out.
Do not panic about your passwords
Your everyday accounts are not at immediate risk from quantum computers.
Ask questions at work
If you handle long-lived sensitive data, ask your IT team about their plan for post-quantum encryption.
What most people miss
- Progress is real but uneven. Companies regularly announce milestones, but practical, large-scale machines are still being developed. Treat dramatic headlines with caution.
- New standards exist already. You do not need to wait for quantum computers to start preparing.
