Precision Electromagnetic Measurements (CPEM), 2010 Conference on
In this paper, an efficient and accurate two-layer standard time distribution architecture is proposed to implement digital time traceability. First, the system uses a clock calibration procedure based on two-way time transfer over a general dialup telephone modem and achieves a couple of milliseconds accuracy. Second, the system uses a delegation time stamping procedure that employs a forward secure proxy signature scheme to provide enhanced validity assurance and extends the RFC 3161 time stamp token to embed the standard time reading. These let users eliminate the blind trust on a commercial time stamping server's clock handling.