Abstract: Quantum information technology is profoundly reshaping the landscape of information security offense and defense. This paper briefly reviews the core advancements in both the“offensive”and“defensive”dimensions of the field. Quantum computing, leveraging properties such as superposition and entanglement, poses a disruptive threat to traditional cryptographic systems. Currently, quantum hardware is in the noisy intermediate-scale quantum era. Its potential attacks on cryptography primarily fall into two categories: Shor’s fully quantum algorithm, which requires millions of qubits—far beyond current technical capabilities, and the quantum-classical hybrid algorithm proposed by Yan Bao, Long Gui-Lu, et al. (the Yan-Long algorithm), which has demonstrated potential threats but still requires further validation before it can feasibly break large-scale cryptography.
In contrast, quantum communication builds a defensive system grounded on the principles of quantum mechanics. It centers on three core technologies: quantum key distribution, which transmits random numbers via quantum states to establish keys for confidential communication when combined with the one-time pad, quantum secure direct communication, which enables the direct transmission of secret messages while offering eavesdropping detection and location exposure alert capabilities, and quantum teleportation, which uses quantum entanglement to achieve the long-distance transmission of unknown quantum states and serves as a foundational pillar for future quantum networks.