Will Quantum Computers Render Global Cryptography Useless? [Im Juhyung's Tech Talk]

Quantum Computer Operating with Overlapping Qubits of 0 and 1 Information Values
Exhibits Much Higher Computational Performance Than Conventional Computers
Capable of Neutralizing Complex Encryption Technologies
Concerns Arise That It Could Become a Hegemonic Weapon for Major Powers

US internet company 'Google' quantum computer research team. / Photo by Google

[Asia Economy Reporter Lim Ju-hyung] In September last year, the research team of the American internet company Google declared the world's first 'quantum supremacy,' sparking a surge of interest in quantum computers both domestically and internationally. Quantum supremacy refers to the moment when a quantum computer surpasses the performance of the theoretically most powerful supercomputer. In other words, Google claimed to have created a computational device more powerful than all existing and future classical computers.

However, some scientists expressed concerns upon hearing this news. They warned that the computational power of quantum computers could be so overwhelming that global encryption technologies might be instantly rendered ineffective, potentially causing significant economic and social turmoil.

So, what exactly makes quantum computers so powerful? Will the advent of quantum computers indeed pose a crisis to security systems?

To understand quantum computers, we first need to know how classical computers operate. The computers we currently use contain various chips inside the main body, such as the Central Processing Unit (CPU), Graphics Processing Unit (GPU), and memory cards. These chips are made up of very small semiconductors called 'transistors.'

A transistor is a kind of switch that emits a specific signal depending on whether it is turned on or off. When current flows through the transistor to turn the switch on, it represents 1; when the current is blocked and the switch is off, it represents 0. These minimal signal units, 1 and 0, are called 'bits.'

Computer chips combine the 1 and 0 signals from countless transistors to create various logic circuits. This enables computers to perform tasks ranging from simple calculations to advanced graphic processing. Therefore, the performance of classical computers depends on how many transistors are integrated into the chip.

Various transistors. / Photo by Wikipedia capture

As a result, the electronics engineering field has long focused on reducing transistor sizes to increase chip integration density. A state-of-the-art computer chip contains billions of transistors. Today, transistor sizes are approximately 7 to 14 nanometers, approaching atomic scale.

The problem arises when transistors shrink to atomic sizes. The smaller the transistor, the more the 'quantum tunneling effect' occurs. This phenomenon allows tiny particles like electrons to pass through barriers, causing transistors smaller than atomic scale to malfunction as switches.

The concept devised to overcome this physical limitation is the quantum computer. Unlike bits that select and send either 1 or 0 signals based on transistor switches, quantum computers use 'qubits,' which hold information values of 1 and 0 in 'superposition.' This is possible because quantum computers operate under microscopic physical laws that are much smaller than the classical physical world we perceive.

Thanks to the characteristics of qubits, quantum computers can perform calculations much faster than classical computers. For example, a computer with 4 bits can produce 16 possible results by combining bits, but it must perform 16 calculations to reach the desired result. However, since qubits exist in a superposition of 1 and 0, all possible results appear simultaneously, significantly reducing computation time.

Therefore, quantum computers can possess computational power that surpasses even supercomputers composed of thousands of high-performance cores. This is exemplified by Google's quantum computer chip 'Sycamore,' which claimed quantum supremacy on September 20 last year.

According to the paper published by Google's research team in the British scientific journal 'Nature,' Sycamore completed a calculation in just 200 seconds that would take a supercomputer 10,000 years to finish.

However, some scientists who reviewed this research expressed concerns that the development of quantum computers could trigger a global security crisis.

Google 53-Qubit Quantum Computer Chip 'Sycamore' / Photo by Google

Google's Sycamore is a quantum computer using 53 qubits. A quantum computer implemented with only 53 qubits has already surpassed all classical computers, and as quantum computer adoption accelerates and further research is conducted, computational power will increase exponentially. This means hardware with the potential to instantly break existing encryption technologies has been created. National security facilities such as bank networks, credit card information, and nuclear power plants could be compromised by a single computer.

In the United States, concerns have been raised that potential rival countries like China could cause massive damage to critical infrastructure through 'hacking wars' using quantum computers.

Dr. Arthur Herman, head of the 'Quantum Alliance Initiative' at the Hudson Institute in the U.S., wrote in a column for the American media 'The Wall Street Journal' last year, "China is investing billions of dollars in quantum computers to develop a 'killer app' that can neutralize all encryption codes," and urged, "The U.S. must establish a national security strategy to protect data, networks, and infrastructure from quantum attacks."

So, will quantum computers become strategic weapons for powerful nations?

The future is uncertain, but the academic consensus is that practical quantum computers are still a long way off. Currently, quantum computer research faces challenges starting with maintaining qubits in a stable state.

Qubits function only in a special state called 'quantum coherence,' which requires complex laser beams to individually target and fix each atom. With current technology, even stabilizing 50 qubits is a difficult task.

However, a bigger problem is that quantum computers are currently machines with no practical use. Computers alone cannot do anything; they require computer programs?software?that instruct the hardware to perform specific tasks. Classical computers can perform various tasks thanks to highly developed software.

Quantum computing is still in its infancy. Programming languages for quantum computers have yet to be developed, and there are no developers to create and maintain software. Even if a quantum computer with tremendous computational power could be built right now, it would still take a long time before it could actually operate.