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The Unbreakable Code Is Broken: Quantum Computing and the Encryption Crisis
Everything you currently consider secure is going to need to be rebuilt. The window to do it is open. It will not stay open indefinitely.
Everything transmitted today over conventional encryption is potentially already sitting in a foreign government's database, waiting for the key that quantum computing will eventually provide.
In Episode 8 we asked whether machines should be permitted to decide who dies, established that the technology to do exactly that already exists and is already deployed, and concluded that the international community's response has been, by any honest assessment, inadequate to the scale of the problem. Today we're doing something slightly different. Today's topic is genuinely technical — it involves physics, mathematics, and computer science at a level that can feel intimidating. Stay with it, because the practical implications affect every single person reading this, today, right now, regardless of whether they've ever thought about quantum mechanics in their life.
Today we're talking about quantum computing. And more specifically, what quantum computing means for encryption — the mathematical system that keeps your bank account, your messages, your medical records, your passwords, and essentially every piece of sensitive digital information you possess safe from people who would like to have it. The short version: the encryption protecting most of that information is going to break. Not might break. Is going to break. The question is when, and whether we will have replaced it with something better before it does.
01 — What Encryption Actually Is
Encryption is, at its core, a mathematical lock. You take a piece of information and scramble it using a mathematical process that can only be reversed if you have the correct key. The security of modern encryption doesn't rely on the scrambling process being secret. It relies on the scrambling process being mathematically hard to reverse without the key. Most modern public-key encryption relies on the fact that multiplying two very large prime numbers together is trivially easy, but taking the result and working out which two prime numbers produced it is extraordinarily difficult. A conventional computer, working through every possible combination, would take longer than the age of the universe to crack a well-implemented modern encryption key.
This is what makes the internet secure. The entire architecture of digital security, trillions of dollars of commerce, the privacy of billions of people, and the security of critical national infrastructure all rest, ultimately, on this mathematical hardness. Now enter quantum computing.
02 — What Quantum Computing Actually Does
A classical computer processes information as bits — each bit is either a 0 or a 1. A quantum computer processes information as qubits. A qubit, exploiting quantum mechanics, can exist in a superposition of 0 and 1 simultaneously — until it is measured. The practical consequence is that a quantum computer can, in certain circumstances, explore multiple computational paths simultaneously in a way that a classical computer fundamentally cannot.
In 1994, mathematician Peter Shor developed an algorithm that, run on a sufficiently powerful quantum computer, can factor large numbers exponentially faster than any known classical algorithm. Shor's algorithm would reduce the time required to crack current public-key encryption from longer than the age of the universe to hours or minutes.
Let that sit for a moment.
03 — Harvest Now, Decrypt Later
Current quantum computers are nowhere near the scale required to crack modern encryption keys. But "right now" is doing a lot of work in that sentence. The consensus among cryptographers and intelligence professionals is that cryptographically relevant quantum computers are likely somewhere between ten and thirty years away. The range of uncertainty is, frankly, uncomfortable given what's at stake.
What makes this particularly urgent is a threat that doesn't require quantum computers to exist today. The attack is called "harvest now, decrypt later" — and it is almost certainly happening right now, at scale, executed primarily by nation-state intelligence services. The strategy is simple: intercept and store encrypted communications and data today, in their currently unbreakable form, and keep them until quantum computers capable of decrypting them become available.
Everything transmitted today over conventional encryption is potentially already sitting in a foreign government's database, waiting for the key that quantum computing will eventually provide.
04 — The Response: Post-Quantum Cryptography
The good news — and there is genuine good news here, which is somewhat novel for this series — is that the cryptographic community has been working on this problem for years and has produced real solutions. Post-quantum cryptography refers to encryption algorithms designed to be secure against both classical and quantum computers, using different mathematical structures that current theoretical work suggests are resistant to quantum attack.
In 2024, the US National Institute of Standards and Technology finalised the first set of post-quantum cryptographic standards after a six-year evaluation process. These standards represent the beginning of the transition from quantum-vulnerable to quantum-resistant encryption. This is a significant achievement. It is also the beginning of a migration process that will need to touch essentially every piece of secure digital infrastructure on earth — and complete that migration before cryptographically relevant quantum computers arrive. That migration is underway, slowly and unevenly. The systems that are hardest to update — embedded systems in critical infrastructure, legacy government systems, medical devices — are exactly the systems where the failure to update will be most consequential.
05 — The Geopolitical Dimension
Quantum computing represents potential advantages not just in breaking encryption but in drug discovery, materials science, logistics optimisation, financial modelling, and artificial intelligence. The country or alliance that achieves meaningful quantum advantage across these domains first gains a set of capabilities that would represent a significant shift in economic and military power. China's investment in quantum technology is, by any measure, extraordinary — the world's longest quantum communication network, significant hardware milestones, and quantum as a stated national strategic priority. The United States has significantly increased federal investment and imposed export controls. We are already in a quantum technology race.
Tomorrow we're going somewhere warmer — literally. We're talking about climate technology. Specifically the race to develop, deploy, and scale the technologies that might actually address the climate crisis: fusion energy, direct air capture, green hydrogen, and whether Silicon Valley's optimism about technological solutions is warranted or a convenient excuse to avoid the harder work of changing how we actually live. See you then.
Switched On is a daily technology series covering AI, social media, data privacy, and the digital forces reshaping modern life — with no corporate spin, no false comfort, and absolutely no mercy for buzzwords.
