US Patent 10903986 Cryptographic key management for end-to-end communication security

Technology can be used for sending and receiving messages on a CAN bus with a plurality of ECUs. The technology can include identifying a first message to send to a receiving ECU from a sending ECU; incrementing a sender-version message counter for the message type; determining to create a second session for the message type in the sending ECU; generating a second sender-version session key to be used during the second session in the sending ECU; and resetting the sender-version message counter. The technology further includes processing the first message using the second sender-version session key, including performing an operation to combine the sender-version message counter with the first message to create a combined message and encoding the combined message using the second sender-version session key to create an encoded message. The technology further includes sending the encoded message to the receiving ECU on the CAN bus.