Quantum security is the fastest commercialized field among quantum technologies. In South Korea, major communications companies such as SK Telecom, KT, and LG Uplus, along with quantum technology startups, have already showcased quantum security technologies. With the rapid growth of the information protection market and the importance of military security technologies being emphasized, corporations are also entering the competition to secure a lead in quantum security technologies.
Han Sang-wook, President of the Korean Quantum Information Society (KIST Principal Researcher), said, “As quantum computers become commercialized, concerns that existing public key encryption may become vulnerable are gradually becoming a reality,” adding that “the necessity for technologies to counter the threats of quantum computers is increasing day by day.”
Representative technologies in the field of quantum security include Quantum Key Distribution (QKD) and Post-Quantum Cryptography (PQC). QKD is a method of transmitting encryption keys using photons (light particles). It allows for sharing encryption keys directly using quantum mechanics, which can prevent attacks from hackers or quantum computers. An encryption key serves as a type of guideline for encryption and decryption.
On the other hand, PQC does not use quantum mechanics directly. It employs difficult problems that cannot be solved even by quantum computers to thwart attacks using quantum computers. Both technologies are evaluated to have already reached a commercialization level.
◇Blocking hacking and data theft by embedding data in quantum
The greatest strength of QKD is its strong security. The scientific and technological community regards QKD as an absolutely safe security technology. The photons used to transmit the encryption key in QKD are indivisible particles. Given that they cannot be divided, it is fundamentally impossible to siphon off part of the data. Even if photons are hijacked, the quantum information changes, making hacking or eavesdropping impossible. Director General Han noted, “If the theory of quantum mechanics is not flawed, QKD cannot be broken by any means,” stating that “domestic and international corporations are already in the early stages of commercialization.”
There are still challenges that QKD technology must address. The biggest issues are short communication distances and high expenses. The scientific and technological community is currently researching new protocols that can extend the communication range beyond the widely used QKD protocol, 'BB84.' Recently, a protocol receiving attention is 'TF QKD,' which can achieve a maximum communication distance of up to 1,000 km, more than three times the existing maximum distance of 300 km of BB84. If TF QKD is commercialized, it will also be possible to implement a QKD system covering all of South Korea.
There is also attention on efforts to reduce expenses using semiconductor technology. This entails developing a chip version of the quantum interferometer that directly handles quantum signals in QKD devices. If a quantum interferometer can be made into a chip, semiconductor processes can be employed, thereby reducing infrastructure investments and lowering production costs. In South Korea, organizations like KIST and the Electronics and Telecommunications Research Institute (ETRI) are researching this method.
Domestic research institutions and corporations have strengths in 'one-to-many' communication technologies aimed at reducing QKD expenses. While existing QKD is specialized for one-to-one communication, one-to-many communication installs QKD on a communication relay server. This is expected to significantly lower the introduction costs of QKD devices that can reach up to 200 million won.
◇Combining QKD and PQC for cost-effectiveness
PQC is another security technology aimed at countering threats posed by quantum computers. PQC has the advantage of being relatively inexpensive as it does not require separate hardware. Its security is also superior to current encryption technologies. However, because it is still difficult to predict how much quantum computers will advance in the future, there are assessments that its security may somewhat decline in the long term.
The United States has already legalized the transition to PQC for government communication systems and is actively implementing it. In 2022, the U.S. passed the 'Quantum Computing Cybersecurity Preparedness Act (H.R.7535)' and announced guidelines for federal agencies' transition to PQC. Samsung SDS is participating in a project by the National Institute of Standards and Technology (NIST) supporting the U.S. government's transition to PQC. However, South Korea has yet to legislate for the introduction of PQC.
Recently, interest in hybrid methods that combine QKD and PQC is also increasing. The strategy is to enhance efficiency by combining the strengths of QKD, which offers excellent security, with the inexpensive and efficient PQC.
Director General Han noted, “There are attempts to connect base stations using QKD for security, while user terminals are connected via PQC, aiming to capture both security and cost reduction,” adding that “there are also discussions about using QKD for communication and PQC for authentication and electronic signatures.”
Domestic corporations are also focusing on the development of hybrid quantum encryption technologies. SK Telecom announced that it developed QKD-PQC hybrid technology with Swiss quantum encryption company id Quantique (IDQ) last year. The strategy is to enhance security by utilizing both encryption technologies simultaneously. KT also completed a VPN technology demonstration using the same method last year.
The South Korean government is demonstrating a strong commitment to fostering quantum technology and is increasing investments. The aim is to build an ecosystem where domestic corporations can thrive. Yoon Ji-won, representative of the quantum startup SDT, remarked, “We are in the stage of examining whether we can create standards by country and appropriate protocols,” adding, “In South Korea, we are exploring how to enhance applicability through practical applications in hospitals, universities, and information agencies.”
Domestic corporate officials see the semiconductor technology and production capabilities possessed by South Korea as a strong competitive advantage. Expectations have surfaced that, through supply chain connections with the United States, which leads in quantum technology, it could be nurtured into a second semiconductor industry.
Representative Yoon stated, “While it is true that the United States is rapidly advancing in terms of technology level and possesses good intellectual property (IP), whether they can produce well is a separate issue,” noting that “from the U.S. perspective, directly producing quantum security products may not be a high-value-added industry.”