By Kwak Soo-keun

Published 2025.09.14.

On the 3rd, Second Vice Minister of the Ministry of Science and ICT Ryu Je-myeong is examining quantum cryptography-related equipment at the on-site meeting for quantum security innovation held at Kookmin University's Quantum Campus in Seongbuk-gu, Seoul. /Ministry of Science and ICT

Three days ago at Kookmin University’s Quantum Campus in Seongbuk-gu, Seoul. On that day, the Ministry of Science and ICT hosted the “Quantum Security Innovation Meeting,” attended by representatives from the three major telecom companies and quantum-related enterprises. George Joo, an executive at Samsung SDS, who served as a presenter, stated, “The ‘Harvest Now, Decrypt Later’ (HNDL) attack, where encrypted data is hacked first and decrypted later when quantum technology advances, poses a significant threat to the nation. Preparations are urgently needed, starting with the public sector, which stores large amounts of long-term data.”

?“Steal First, Decrypt Later”

HNDL, which sometimes uses “Hack” instead of “Harvest,” is a strategy gaining attention from hackers ahead of the quantum technology era. Even data that cannot be decrypted now due to encryption is stolen first, with the plan to decrypt it later using advanced quantum computers. Experts warn that while this strategy seems simple, it could become a major threat in the near future. Its covert and prolonged nature makes it difficult to detect. Since intercepted data is stored long-term rather than used immediately, there are no immediate warning signs like system failures or file corruption. The lack of visible indicators means the victim might not even realize they have been hacked.

Hackers exploit network vulnerabilities or infiltrate data storage systems to steal emails, corporate trade secrets, military communications, and more, storing them systematically. They wait for the day when quantum computers can decrypt the stolen data’s encryption. Experts believe that not only the public keys used in today’s asymmetric encryption for e-commerce but also elliptic curve encryption, used in Bitcoin, could be neutralized by quantum computers in the near future.

?Preparation Through Quantum-Resistant Cryptography

Industry insiders anticipate that encrypted data requiring long-term storage under legal or internal policies—such as in government, finance, and other sectors—will be prime targets for HNDL attacks. There are concerns that data considered safe today due to encryption could become a risk in the near future. Notably, hostile nations, including North Korea, are indiscriminately targeting not only government data like diplomacy and military intelligence but also corporate trade secrets and intellectual property. If these sensitive data are decrypted using quantum technology, they could threaten national security.

The technology to counter this is Post-Quantum Cryptography (PQC), or “quantum-resistant encryption.” Designed to resist decryption by quantum computers, it serves as a shield for the future. The U.S. National Security Agency (NSA) and others recommend transitioning to PQC as a priority for government and public security.

Quantum Key Distribution (QKD), an advanced technology for securely exchanging encryption keys, is also gaining attention as a means to prevent hacking in the quantum era. QKD detects and responds to hacking attempts by exchanging photons using separate quantum optical devices.

Experts emphasize the need to prepare for hacking threats by utilizing both technologies. At the quantum security meeting, Gwak Seung-hwan, CEO of GQT Korea, stated, “The hybrid application of QKD and PQC should be expanded. The government should actively support encryption technologies that neutralize data theft itself.”

The government plans to promote a hybrid model combining PQC and QKD quantum security technologies for national core infrastructure by 2030. The approach will prioritize PQC implementation with QKD as a supplementary measure. The goal is to establish a foundation for transitioning to a PQC system by 2030 and complete a secure cryptographic framework by 2035. To this end, a budget of 3.6 billion Korean won has been secured for next year to support PQC-QKD hybrid technologies.

Some argue, “Just as generative AI experienced a ‘ChatGPT moment’ with its sudden leap, quantum computing technology could undergo a ‘quantum jump’ at an unexpected moment. Quantum encryption policies targeting 5–10 years ahead should be accelerated.”

Ryu Je-myeong, Second Vice Minister of the Ministry of Science and ICT, stated, “Cybersecurity incidents and quantum security issues are often overlooked in normal times, but when a crisis occurs, it’s essential to fix the barn door before the horse bolts. There must be a shared recognition that quantum security is an imminent risk, and the government and public institutions should take the lead.”

? This article has been translated by Upstage Solar AI.