In recent years, the security of time transfer has received extensive attention. Various network systems, such as computer networks, finance, power and energy networks, etc., all require a unified time base. On May 12, it was learned from the University of Science and Technology of China that Pan Jianwei and his colleagues Peng Chengzhi and Xu Feihu of the school used the “Mozi” quantum science experimental satellite to realize the principle experimental verification of quantum safe time transfer for the first time in the world. It lays the foundation for building a safe satellite navigation system in the future. The results were published online in the international academic journal Nature Physics on May 11.
Based on the principle of quantum non-cloning, the time transfer technology based on the single-photon quantum state can fundamentally ensure the security of the signal transmission process. Pan Jianwei’s team first proposed a quantum-secure time synchronization scheme based on two-way free-space quantum key distribution technology. In this scheme, the single-photon quantum state simultaneously acts as a signal carrier for time transfer and key distribution for time synchronization and key generation. The keys generated by this process are used to encrypt classical time data, thus ensuring the secure transmission of time data.
Based on the “Mozi” quantum science experimental satellite, Pan Jianwei’s team broke through key technologies such as satellite-to-ground single-photon time transfer, high-speed satellite-to-ground two-way asynchronous laser time transponder, etc., and realized the technical verification of satellite-to-ground quantum security time synchronization. The satellite-to-earth time transfer with 30ps precision has reached the international advanced level of satellite-to-ground laser time transfer.
The reviewers spoke highly of: “It has once again surpassed the current state of the art in the field of quantum experiments in space…it is crucial for the practical application of quantum technology.” The research results will greatly promote the research and application of quantum precision measurement related fields.
High-precision time transfer is the core technology for applications such as navigation and positioning. Currently widely used time transfer technologies mainly include satellite navigation and positioning, optical fiber networks and other time transfer schemes. However, the currently widely used time transfer technology faces the potential risks of various attacks such as data tampering and signal spoofing.