In the film *Leave the World Behind*, Tesla vehicles crash into one another. The cars speed forward, slamming into the vehicle ahead before finally stopping. Another car then charges forward with a deafening roar. What they all have in common is that every driver's seat is empty — a scene suggesting what could happen if autonomous driving systems are hacked and vehicles begin operating on their own.
In a manufacturing plant, humanoid robots suddenly stop their tasks and attack human workers. Some robots mistake people for objects to be processed. Control room staff try to rein in the malfunctioning robots, but their commands have no effect. The control system has been hacked by a quantum computer. Faced with robots possessing physical strength, humans are left completely defenseless.
These may seem like scenarios confined to movies and imagination, but they could very well happen in reality. Artificial intelligence agents and physical AI are rapidly entering everyday life. If security systems are breached, the damage could extend far beyond the digital realm into the physical world. As quantum computing technology advances, experts warn that existing cryptographic systems could be rendered useless. Specialists agree that now — as AI transformation (AX) and robotics transformation (RX) dominate the conversation — is the time to prepare with next-generation security technologies such as post-quantum cryptography (PQC).
Encryption That Even Quantum Computers Cannot Break
Security concerns stemming from quantum computing have recently surged in the cryptocurrency startup industry. The fear is that once quantum computers become sufficiently powerful, they could compromise not only Bitcoin but the security of cryptocurrency wallets broadly. This is not limited to crypto. The cryptographic systems currently used across telecommunications, finance and other sectors are highly vulnerable to being neutralized by quantum computers.
The vulnerability stems from how current encryption works. Public-key cryptography — used for user and device authentication as well as digital signatures — has relied on the computational difficulty of problems such as the prime factorization of large numbers to ensure security. These were problems that conventional computers could not realistically solve.
Quantum computers upend that premise. They can solve prime factorization in a short time, fundamentally threatening existing cryptographic systems. This means major services built on that framework — including internet banking, telecommunications and data transmission — could all be affected. "Once quantum computers arrive, even the encryption behind public digital certificates could be cracked in a single day," said Chun Jung-hee, CEO of CryptoLab. "It would also become possible to figure out a password just by looking at a Bitcoin wallet address." Yoon Hyo-jin, vice president of Samsung SDS's Security Algorithm Lab, added: "With the advent of quantum computers, the security of encryption algorithms that relied on public keys doesn't just get cut in half — it drops to zero."
Post-quantum cryptography is widely regarded as the leading countermeasure against this threat. PQC is a cryptographic system designed around mathematical problems that remain difficult even for quantum computers to solve. Lattice-based cryptography is cited as a representative approach. Chun explained: "It's like marking a point on a sheet of rice paper and then trying to find the nearest point. As you move into higher dimensions, finding the answer becomes impossible."
South Korean telecommunications companies including KT are developing quantum key distribution (QKD) to counter the security threats posed by quantum computers. Instead of sending encrypted data directly, QKD transmits the encryption key itself via quantum signals. The moment an attacker intercepts the quantum signal, the quantum state changes, making the data unreadable to the sender, receiver and attacker alike. This is why no amount of advancement in quantum computing can break this method's security. Yoon cautioned, however: "The purpose of an attack isn't always data collection — if the goal is to sever communications, this method is also not safe." He noted that "implementing this on servers, PCs and mobile devices requires server-grade hardware, and the transmission range is limited to tens of kilometers." The industry therefore points to a hybrid approach combining PQC and QKD as the most viable alternative.
Cryptographic Technology Arriving Ahead of Quantum Computers
Quantum computers have not yet reached the commercialization stage, but next-generation cryptographic technologies designed to counter them are already being deployed in real life. Among quantum cryptographic technologies, homomorphic encryption stands out as a practical security solution with actual use cases. Homomorphic encryption allows data to be combined and analyzed while remaining encrypted. Previously, encryption had to be removed before data could be combined or analyzed, creating a risk of information leakage. With homomorphic encryption, analysis is possible without decrypting the data, significantly reducing that risk.
This technology was implemented as an actual service during the COVID-19 pandemic. CryptoLab launched an application called "Codongi" that encrypted users' smartphone GPS data with homomorphic encryption, then cross-referenced it with confirmed patient movement data to check contact status in real time.
More recently, CryptoLab has been conducting pilot work to apply homomorphic encryption to LG Uplus's AI call agent ixi-O. Ixi-O is a service that converts voice calls on mobile phones to text and generates various call data on the device. LG Uplus plans to incorporate homomorphic encryption so that call data is stored in encrypted form and users can search for keywords within call contents without decrypting the data. "In the United States, it takes more than a year just to obtain permission to review relevant data in order to find eligible patients before conducting clinical trials for new treatments," Chun said. "Homomorphic encryption allows patient data to be safely reviewed and clinical trial participants to be recruited quickly, which is why the medical community is highly interested in this technology."
Security Investment Overshadowed by AX
Despite its importance, investment in and attention to security are being pushed to the back burner. "Just a few years ago, a security breach meant financial losses at most," Yoon said. "Now, with everything connected through the cloud, areas that could directly threaten people's lives are under attack, making security critical."
There are also concerns that attackers may already be illegally collecting significant volumes of data. The fear is that attackers could harvest encrypted data now and attempt to decrypt it later when quantum computing technology matures. State secrets, financial data and health records could be prime targets. "Hackers typically wait until the volume of leaked data accumulates to a certain level before belatedly announcing the breach," Chun said. "This can amplify the damage."
Major countries are currently pushing to adopt post-quantum cryptographic systems. The United States, the United Kingdom, the European Union, Canada, Japan and China all aim to transition from existing encryption to PQC by 2035 at the latest. "Starting this year, the U.S. government is giving bonus points to vendors that use post-quantum cryptography when certain web browsers are supplied to government agencies," Yoon explained. "From 2030 to 2033, regulations will prohibit the use of legacy encryption algorithms."
The South Korean government has also laid out a blueprint to transition existing encryption to PQC by 2035. However, extending these preparations to the private sector has been slow. Private companies are prioritizing AX over security. Choi Young-seok, chief strategy officer at BTQ Technologies, said: "Given that AI infrastructure itself is exposed to quantum threats, quantum security is essential infrastructure for the AI era." He added, however, that "unlike the AI market, which is attracting explosive investment, the quantum security sector is receiving relatively little attention."
Industry officials say the immediate priority is conducting a thorough audit of where and how existing encryption methods are being used, and then expanding investment in next-generation security technologies.