Network timing synchronization

An apparatus, comprising:

• a first clock circuit configured to maintain a first time value associated with a network;
• a synchronization circuit configured to:
• determine a propagation delay over the network for receiving synchronization information associated with a second clock circuit that maintains a second time value, wherein determining the propagation delay includes the synchronization circuit sending a first message over the network and receiving a second message over the network;
• determine an expected offset between the first time value and the second time value based on departure and arrival times of the first message and departure and arrival times of the second message;
• receive synchronization information specifying a timestamp of the second time value;
• and
• determine whether the timestamp is valid by comparing the expected offset to an offset calculated based on the timestamp.

An apparatus, comprising:

• an electronic control unit (ECU) configured to control operation of a vehicle, wherein the ECU is configured to communicate traffic over a network in accordance with a master clock for the network;
• and
• a secure circuit configured to:
• receive a synchronization message specifying a time value associated with the master clock and an integrity check value for the synchronization message;
• determine whether the synchronization message is valid based on the integrity check value;
• and
• in response to determining that the synchronization message is valid, provide time information associated with the time value to the ECU.

An apparatus, comprising:

• a first circuit having a first clock, wherein the first circuit is configured to determine a validity of a timestamp of a second clock used to synchronize the first clock with the second clock by:
• sending a first message to a second circuit having the second clock, wherein the first message includes a first nonce;
• receiving a second message from the second circuit, wherein the second message includes a second nonce and is associated with the timestamp;
• receiving a third message from the second circuit, wherein the third message includes information indicative of the first nonce and the second nonce;
• and
• based on the first nonce, the second nonce, and the information, determining whether the timestamp is valid.