The Engineer Racing to Make Quantum Computers a Reality — and Potentially Break the Internet

Craig Gidney, a little-known quantum computing engineer at Google, is working to run Shor's algorithm, which could crack the encryption securing online communications and banking.

The Man Behind the Algorithm

Craig Gidney is a name familiar to those deep inside quantum computing circles, yet he remains largely unknown to the general public. Based at Google Quantum AI in California, he has written no books, gives few keynote lectures, and rarely speaks to the press. Despite his low profile, his recent co-authored studies have generated significant attention. Gidney is now focused on a single, high-stakes goal: finding a way to run what many consider the world’s most dangerous algorithm on a quantum computer.

The Threat of Shor’s Algorithm

Today’s digital security relies on encryption systems that are difficult for conventional computers to break. Common methods involve factoring large numbers or solving problems based on abstract mathematical objects called elliptic curves. In 1994, theoretical computer scientist Peter Shor at the Massachusetts Institute of Technology discovered that a sufficiently powerful quantum computer could solve these problems with ease. The algorithm he developed, known as Shor’s algorithm, would render most current encryption useless. The day it runs on a real machine — often called Q-Day — could mark the end of digital privacy as we know it, potentially exposing emails, bank accounts, and other sensitive data.

Making the Impossible Possible

For years, the threat of Q-Day seemed distant because quantum computers themselves were not yet practical. These machines rely on qubits, and a truly powerful version would need millions of them — a goal that long appeared out of reach. However, recent progress by several firms and research teams has changed the outlook. Much of the credit for accelerating the timeline goes to Gidney. He has been leading efforts to make Shor’s algorithm run on smaller quantum computers, ones that could plausibly be built in the near future. While Shor provided the theoretical recipe, Gidney’s work is akin to figuring out how to cook that recipe with minimal ingredients. His own stated goals are twofold: to prove that quantum computers can function as intended, and to inform cryptographers about how to protect against them.

A Quantum Vision

Gidney’s interest in quantum computing goes beyond technical achievement. He sees the machines as a way to tap into the fundamental structure of reality. Most physicists view the world as quantum at its most basic level, made up of particles and fields. Gidney has described the universe as being composed of quantum information at its foundation, a resource that humans currently cannot manipulate. He compares it to the human-scale world, where we can easily measure objects with thermometers, cameras, and rulers. A quantum computer, he says, would be the quantum equivalent of those tools. For him, focusing on Shor’s algorithm is simply the clearest path to demonstrating that quantum computers are worth the hype. His ultimate desire, as he puts it, is just to make the quantum computer work.