HE Kang-yuan1, WU Gui-chen1, FENG Ping1,2

（1. National Time Service Center, Chinese Academy of Sciences, Xi’an, Shaanxi 710600, China;

 2. Graduate University of Chinese Academy of Sciences, Beijing 100039, China）

Abstract: A time authentication system is developed, which is realized by means of the public switched telephone network. And a standard time service will be provided to the digital time stamp service organization via the telephone network. The results of measure show that the corresponding time synchronization precision reaches the range of ±0.3 ms. The precision satisfies the digital time stamp service organization, and can be used to supply time authentication service to E-government affairs and E-commercial affairs such as banking, securities, stocks, futures exchanges, etc.

Keywords:public switched telephone network；digital time stamp；standard time；time synchronization；electronic government (or commercial) affairs；cipher algorithm