Redundant Schemes or How to Counter the Delay Attack on Time Synchronization Protocols

The nature of communication networks is forcing scientists to consider security mechanisms, in order to protect their protocols from different manipulations and cyber-security attacks. The upcoming revision of IEEE 1588 will include concrete suggestions on how to harden the PTP time synchronization protocol against such attacks. One of the most important options is the use of redundant paths and/or participants. This paper discusses different issues that arise when using redundancy in combination with time synchronization. It further focuses on a certain attack specific to time synchronization protocols, the delay attack. A flexible attacker device was developed and used to prove the effectiveness of the implemented measures.