he development of quantum technology is not merely a scientific and economic
computer will be able to hack into and disrupt nearly all current information
technology. Both the national security risks and the economic benefits necessitate
that the U.S. win the race to the world’s first fully operational quantum computer.
How will quantum computers be able to hack into today’s seemingly secure
All current computers, even supercomputers, use electrical signals to process data in
a linear sequence of “bits,” where each bit is either a one or a zero. This classical
system of ones and zeros is referred to as the binary system.
is a physical photon, rather than an electrical signal. In the bizarre world of quantum
mechanics, these photons can be in two states at once, essentially functioning as a
zero and a one at the same time. This allows a quantum computer to do two—or
more—computations at once. Add more qubits, and the computing speed grows
exponentially. These quantum physical properties will allow quantum computers to
solve problems thousands of times faster than today’s fastest supercomputers.
computer’s speed of operations but its ability to dramatically reduce the number of
operations needed to get to a result. This increased computing power poses a problem
for asymmetric encryption, the encryption schema used to protect nearly all of today’s
electronic data. Asymmetric encryption is secure because it is based on math
problems that would take a classical computer centuries to solve.
For example, asymmetric encryption—often called public-key encryption—relies on
two keys. One is the private key, which consists of two large prime numbers known
only to the party securing the data (for example, a bank). The public key sits in
cyberspace and is the product of multiplying together the two private primes to create
a semiprime. The only way a hacker could access such encrypted credit card
information would be by factorizing or breaking down the large public key—often 600
digits or longer—back to the correct two numbers of the private key. This task simply
takes too long for current computers because they must sequentially explore the
potential solutions to a mathematical problem.
F. Arnold Romberg, “Computers and the Binary System,” in Mathematics, 2nd ed., ed. Mary Rose
Bonk, vol. 1 (Farmington Hills, MI: Macmillan Reference USA, 2016), 159–65.
Arthur Herman, “The Computer That Could Rule the World,” Wall Street Journal, October 27, 2017,
Meanwhile, a quantum system is able to look at every potential solution
simultaneously and generate answers—not just the single “best answer,” but nearly
ten thousand close alternatives as well—in less than a second. This is roughly the
equivalent of being able to read every book in the Library of Congress simultaneously
in order to find the one that answers a specific question.
Why is a quantum computer so dangerous?
such asymmetric encryption, including bank and credit card information, email
communications, military networks and weapons systems, self-driving cars, the
power grid, artificial intelligence (AI), and more. While asymmetric encryption is
effective at thwarting today’s hackers armed with classical computers, quantum
computers will be able to hack into these systems and disrupt their operation and/or
steal protected data.
Experts like to refer to the day that a universal quantum computer will be able to hack
into asymmetric encryption as “Q-Day” or “Y2Q”—reminiscent of the Y2K computer
meltdown that was thankfully avoided due to the hard work of technologists.
In addition, a quantum computer attack could be virtually impossible to detect
because the combination of the available public key with the quantum-deciphered
private key would allow a hacker to impersonate someone in the targeted system.
Therefore, someone within the hacked network would have to notice unusual internal
activity in order to detect a hack—and even then, it would be difficult to determine if
the disruptive activity is the result of a quantum computer attack or another type of
By any measure, then, a quantum computer, which will be able to hack into
asymmetric encryption, poses an obvious national security threat. At its worst, Q-Day
could be the equivalent of a quantum Pearl Harbor—especially because a large
proportion of American infrastructure systems are operated electronically, including
the grid, water purification and transportation systems, and traffic light and railroad
systems. Even more alarmingly, it would be a stealth Pearl Harbor that no one would
detect until it was too late.
Because there is not a succinct term to refer to a future large-scale quantum computer
that can hack into asymmetric encryption, at Hudson Institute’s Quantum Alliance
Initiative (QAI) policy center, we refer to such a computer as a quantum prime
As discussed later in this section, estimates vary regarding when a
To be precise, a quantum prime computer is one that can reverse-factor large semi-prime numbers
used in asymmetric encryption back to their original prime numbers, or keys. These keys unlock the
Because subatomic particles are inherently unstable, keeping sufficient numbers of
this inherent instability decoherence. When a given qubit decoheres, it loses its
superposition and can no longer act as both zero and one at the same time, but only
one or the other. The ability to compute in the way a quantum calculation requires
therefore disappears. Unfortunately for quantum scientists, the slightest disturbance
can cause a qubit to decohere; this means engineers must constantly work on ways to
mitigate the effects of minute disruptions from the slightest movement, sound, or
even light. This is also why many quantum computers are built inside vacuums and
deep subzero temperatures.
very slowly and take considerable investment in time, money, and human resources.
Achieving the ultimate breakthrough to a quantum prime computer will be the
slowest of all, and some experts say that it may not happen before 2030.
All the same, though a quantum prime computer may still be years off, a significant
horizon: quantum supremacy.