On the 26th, the reporter learned from the University of Science and Technology of China that the academician team of Guo Guangcan, Han Zhengfu, Wang Shuang, and their collaborators have proposed a new quantum key distribution implementation scheme that does not require active modulation and completed experimental verification, providing new ideas for achieving a high reality secure quantum key distribution system. This achievement was recently published in the international academic journal "Physics Review Letters". Quantum key distribution can theoretically achieve unconditional secure key sharing, but factors such as device characteristics, modulation accuracy, and environmental interference may cause real-world security issues in the system. For example, Guo Guangcan's team found that lithium niobate active modulation devices, which are widely used in the system, may be subject to side channel attacks such as photorefraction and leak information. To completely solve the hidden dangers caused by active modulation, Guo Guangcan's research team and collaborators have taken a different approach and designed a quantum key distribution system that does not require active modulation. This system solution overcomes the contradiction of not being able to simultaneously achieve "passive" light intensity modulation and quantum state encoding, and provides a strict secure key rate that takes into account the "finite length effect". The team solved the problem of channel environment interference through fully passive timestamp phase encoding, and solved the problem of excessive data throughput through optimized selection strategies. Finally, a quantum key distribution system without any active modulation was completed, verifying the security and feasibility of fully passive quantum key distribution. This research achievement provides a new idea for achieving a high reality secure quantum key distribution system, and is of great significance for promoting practicality and standardization in this field. (New News Agency)