In an excellent article, long-time tech journalist (and Internet Press Guild colleague) Wayne Rash explains how forthcoming quantum computers could render most computer security worthless. I won't go into the details — he does a great job at that. But in short, quantum computers can solve certain kinds of problems instantly. A lot of computer encryption relies on the fact that traditional computers take a long time to solve those problems: Ergo, that encryption can be broken by quantum computers.
Traditional computers inhabit the same world we do in our daily lives, where physics is predictable. If one billiard ball hits another, you can determine precisely where the second ball will go based on physical factors such as the balls' masses, where they touch, the table's tilt, and so on. These physics are "deterministic", as is the addiiton of ones and zeros in a traditional computer.
But the quantum world rules at the submicroscopic level, a scale so small that things stop being things. When two quantum "billiard balls" collide, they could go anywhere -- and in a complicated mathematical sense, they go everywhere at once. They're completely unpredictable, or "nondeterministic". Quantum computers use such quantum effects to "go everywhere at once" within a problem, and then deliver an answer that's probably (although not certainly) right.
Which brings us to an area unrelated to computers and encryption and billiard balls: Human consciousness.
I've been looking at the intersection of brain science and computer science for a documentary now in development, "Almost a Brain". On one side are projects that map the brain's physical attributes to the tiniest detail, such as the Human Brain Project and the Allen Brain Atlas. These are driven by increasingly powerful supercomputers — the traditional kind, which computes using ones and zeros. As a result, their results are essentially deterministic.
That approach has yielded incredibly valuable results: Detailed brain models replicate the electrical and chemical storm in our heads, while supercomputers interpret the sparks that comprise that storm. As a result we now have tools to understand such matters as drug interactions and neurological conditions better than ever, with greater precision and less experimentation.
But these advances haven't had much effect on our understanding of consciousness. (Perhaps that's because it's essentially a philosophical question that's difficult to put into scientific terms. How can you prove that something has awareness -- or lacks it?) One school of thought holds that a conscious being is in control of its decisions, that its future actions can't be determined from what came before. A conscious being, they say, has "free will". It is nondeterministic. If that's so, deterministic brain models and deterministic supercomputers can never understand it.
Enter "quantum consciousness", a term coined by Sir Roger Penrose and Stuart Hameroff. Penrose theorized that consciousness could be caused by unpredictable quantum effects in 1989. But as a theorist (in math, physics, and philosophy), he couldn't identify a biological mechanism that could cause such consciousness. That came from Hameroff, whose medical training as an anesthesiologist led him to believe that quantum effects exist in a cell structure known as microtubules. These, the two believe, could be the key to understanding the nondeterministic in us -- our "free will". (Dr. Hameroff has agreed to be interviewed for Almost a Brain.)
If they're right, quantum computers could not only break codes: They could be the magic ingredient that gives artificial brains consciousness.
That doesn't mean that we'll actually have conscious machines among us anytime soon. Quantum computing is in its infancy: It's still unable to do much practical work, let alone crack passwords. And economically, there's little reason to spend billions of euros to merge the two into a conscious being.
But you can buy a quantum computer today. And for the deterministic part, supercomputers are approaching the estimated computing power of the human brain. As time and applied research lower the cost of both parts, a conscious, hybrid, classical-quantum computer could upheave society in ways that go far beyond encryption.
Image of a quantum computing chip CC-BY, D-Wave Systems, Inc.