Experimental quantum digital signature over 102 km
Hua‐Lei Yin, Yao Fu, Hui Liu, Qi-jie Tang, Jian Wang, Lixing You, Weijun Zhang, Sijing Chen, Zhen Wang, Qiang Zhang, Teng‐Yun Chen, Zeng‐Bing Chen, Jian-Wei Pan · Physical Review A · 2017
Quantum digital signature (QDS) is an approach to guarantee the nonrepudiation, unforgeability, and transferability of a signature with information-theoretical security. Previous experimental realizations of QDS relied on an unrealistic assumption of secure channels and the longest distance is several kilometers. Here, we have experimentally demonstrated a recently proposed QDS protocol without assuming any secure channel. Exploiting the decoy state modulation, we have successfully signed a one-bit message through an up to 102-km optical fiber. Furthermore, we continuously run the system to sign the longer message ``USTC'' with 32 bits at the distance of 51 km. Our results pave the way towards the practical application of QDS.