| 摘要 |
The present invention is concerned with 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, in particular 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 t send , a synchronization message including a time stamp of the projected send time, and secures the synchronization message still in advance of the projected send time. Securing the synchronization message takes place by suitable cryptographic means allowing at least for authentication of the time stamp at a receiving slave clock, e.g. by calculating and signing a checksum or hash of the synchronization message. At the projected send time, the secured synchronization message is transmitted. |
