Secure clock synchronization

摘要

The present disclosure provides a secure one-step IEEE 1588 clock using either a symmetric or asymmetric protection scheme. Clocks of mission-critical or highly-available devices in industrial automation systems connected to a communication network are synchronized by sending, by a master clock, a synchronization message, e.g., a single message of the one-step-clock type according to IEEE 1588, including a time stamp, and by receiving and evaluating, by a slave clock, the synchronization message. A synchronization component or module of the master clock prepares, or composes, prior to a projected send time, a synchronization message including a time stamp of the projected send time, and secures the synchronization message in advance of the projected send time. Securing the synchronization message occurs by suitable cryptographic means allowing for authentication of the time stamp at a receiving slave clock. At the projected send time, the secured synchronization message is transmitted.

主权项

1. A method of synchronizing clocks connected to a communication network, comprising:
sending, by a master clock, a synchronization message including a time stamp; and receiving the synchronization message by a slave clock, wherein the sending of the synchronization message comprises:
preparing, prior to a projected send time tsend, a synchronization message including a time stamp of the projected send time tsend;securing the synchronization message;starting preparation of the secured synchronization message at a time tprep preceding the projected send time tsend by Δt, wherein Δt is a preparation delay based on a processing capacity of processing hardware generating the synchronization message; andsending, at the projected send time tsend, the secured synchronization message, wherein the sending of the synchronization message comprises: designating, by the master clock, the projected send time tsend for sending the synchronization message by determining the preparation delay time Δt from a present time based on current conditions of the communication network, the processing capacity of the processing hardware generating the synchronization message, and a security scheme utilized to secure the synchronization message.