This application discloses a controller area network node including a controller and a transceiver. The transceiver includes security circuitry to perform various security checks on messages the controller area network node intends to have transmitted over a shared bus in a controller area network. The security circuitry can determine whether the messages conform to the rules associated with a design and a traffic scheduling of the controller area network. Some of those rules include that the controller area network node transmit messages with identifiers that were assigned to the controller area network node, or transmit messages with a specified timing. When the security circuitry identifies one of the messages fails to conform to the rules for the controller area network, the security circuitry can initiate a security action, such as refusing or delaying transmission of the messages or reporting the rules violation to the controller.