Physical-layer identity-authentication mechanism for network time synchronisation using network and precision time protocols

Abstract

Time-spoofing attacks, especially those using time-source spoofing, pose a serious threat to network time synchronisation. Such attacks can be suppressed by authenticating received time-synchronisation messages at the receiving terminal. Current identity-authentication mechanisms under the network time protocol (NTP) and precision time protocol (PTP) are based on cryptography and network-security technologies and have inherent limitations. This study proposes a novel physical-layer identity-authentication mechanism based on a general physical-layer security-architecture for network time synchronisation and a special system-infrastructure model. In this approach, legitimate messages and transmission paths are endowed with unique characteristics, thus the legitimate time source is uniquely identified. The receiving terminal can determine whether the received signal characteristics and transmission path are consistent with the preset conditions, and thus whether the signal comes from a legitimate time source. Simulation results show that under zero-false-alarm conditions, the proposed physical-layer identity-authentication mechanism successfully suppresses all illegitimate messages in channels containing additive white Gaussian noise and in Rayleigh fading channels. Moreover, this mechanism covers all operational modes of NTP/PTP, achieving a reasonable trade-off between security performance and computational complexity. It can thus significantly improve NTP/PTP resistance to time-source spoofing.