By Scott Tilley, ASCF Senior Fellow

October 2020 –

All of today’s computers perform their calculations in the same way. It doesn’t matter if the computer is an old PC from the days of Windows 3.1, the latest and greatest iPhone, or the world’s fastest supercomputer. At the most fundamental level, the underlying architecture is essentially the same, dating back to the earliest primitive machines used to calculate artillery trajectory during World War II.

Computers manipulate bits, which is short for “binary digit.” A bit is the simplest possible representation of a number: it is either on (“1”) or off (“0”). We live in a base 10 (“decimal”) world, with numbers from 0 to 9, but computers operate in this limited base two world. Most computer science students are taught how to convert from decimal to binary. It’s a laborious process, but one that is necessary for a computer to perform its work.

Very old computers used mechanical relays and switches to represent bits. Modern computers use transistors, but the goal is the same: store a single data value of “on” or “off.” This straightforward encoding is very limited in what it can represent. Still, it does mean computers can perform their calculations extremely fast because at the most fundamental level, the computer is simply making a decision based on this “0” or “1” value. By “fast,” consider that some of today’s fastest computers can perform a truly mind-boggling number of calculations per second. For example, IBM’s Summit supercomputer at the Oak Ridge National Laboratory is an exaflop machine, which means it can perform over a quintillion operations per second. That’s a billion billion calculations; 10 followed by 18 zeroes.

But it’s still not fast enough.

The challenge is that there are important problems that simply can’t be solved using a conventional computer, no matter how fast it runs. The most common example is cryptography, which is the technology underlying the encryption we rely on every day to conduct online transactions, like purchasing something with your credit card. The mathematical models used to encrypt the transaction are designed to be virtually impossible to crack because the number of combinations a computer would have to try to break the encryption would take almost forever – even with the Summit supercomputer.

This is an important issue for everyone because it affects American national security. What would happen if there was a way to crack the encryption used for online banking, diplomatic messages, or government communication? Our interconnected electronic infrastructure would be vulnerable to terrorists or adversarial nation-states. Nothing would be secret or secure.

Technology moves inexorably forward, and very soon, there will be a way to accomplish precisely this form of a cybersecurity attack. It’s called quantum computing, and it is one of the two most advanced areas being funded around the world. (The other technology is artificial intelligence.) Quantum computing is a complex topic; the famous theoretical physicist Richard Feynman once said that anyone who claims to understand quantum mechanics doesn’t understand quantum mechanics.

In a nutshell, a quantum computer can perform certain calculations exponentially faster than our current classical computers. This means cracking encryption in real-time. The quantum computer can do this by exploiting two extremely odd facets of the quantum world: superposition and entanglement. Superposition refers to a single quantum bit (“qubit”) being in two states at the same time: not only “1” or “0” but both simultaneously. It sounds counterintuitive, and it is, but it is real. Entanglement refers to qubits being influenced by one other’s state, seemingly faster than the speed of light. Einstein called this “spooky action at a distance.” Taken together, superposition and entanglement make a quantum computer able to perform a massive amount of calculations in parallel, giving it the power to do things like crack encryption.

The scary thing is that quantum computers are now real. Last week, I attended (virtually) a conference from the IEEE on quantum computing. There were over 200 sessions from worldwide experts discussing the latest advances in quantum engineering. Some of the results were truly astounding. Students at our universities can now access quantum computers online to experiment with new ways of solving previously unsolvable problems. Unfortunately, adversarial countries that wish us harm also have access to much of the same technology. We are entering a new scientific arms race, and the costs of failure are alarming.

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Photo: Image: Getty Images/iStockphoto

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