CAN Bus Message Sequence Security via Phase Segmentation
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Solution Overview
Problem
Existing methods for detecting attacks on message sequences transmitted via a data bus, such as a CAN bus, are only partially effective due to limitations in monitoring certain signal send types like IfActive and IfActiveWithRepetition, which allow infiltrated messages to go undetected by matching regular message sequences.
Innovation Solution
A method and device that transmit a message sequence with an informational message during an active phase, a security message to initiate a rest phase, and rest messages at a rest cycle time, where the informational and rest signals differ, allowing for the detection of attacks by checking if the rest phase is initiated with a specified security message.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional attack detection methods are used to monitor CAN bus signal send types, then detection capability is provided, but detection effectiveness is limited and infiltrated messages remain undetected
Solution Approach 1:
The message transmission is segmented into distinct phases: active phase with informational messages and rest phase with rest messages. A security message is transmitted at the transition from active to rest phase to mark this segmentation. This segmentation allows receivers to verify message authenticity by checking the proper initiation of rest phase with the security message, thereby detecting infiltrated messages that disrupt the expected pattern.
Solution Approach 2:
A security message is transmitted in advance before the rest phase begins to mark the transition from active to rest phase. This preliminary action provides a reference point for receivers to verify that the rest phase is properly initiated, enabling detection of attacks that attempt to inject messages during the rest phase or prevent proper phase transition.
2Reliability
If message sequences are transmitted without distinct phase markers, then transmission simplicity is maintained, but security against infiltrated messages is compromised
Solution Approach 1:
A security message is transmitted in advance before the rest phase begins to mark the transition from active to rest phase. This preliminary action provides a reference point for receivers to verify that the rest phase is properly initiated, enabling detection of attacks that attempt to inject messages during the rest phase or prevent proper phase transition.
Solution Approach 2:
The message transmission uses parameter changes to distinguish between phases: informational messages during active phase, a specific security message at phase transition, and rest messages during rest phase. These parameter changes (message content, transmission timing) provide security markers without requiring complex additional protocols, balancing security with transmission efficiency.
Data Source
AI summary
The present invention relates to a method for transmitting a message sequence via a data bus. The method comprises the transmission of an informational message containing an informational signal during an active phase, the transmission of a security message for initiating a rest phase and the transmission of rest messages containing a rest signal at the interval of a rest cycle time during the rest phase, wherein the informational signal and the rest signal differ from each other and wherein the security message and the rest messages differ from each other. Furthermore, the invention relates to a device for transmitting a message sequence via a data bus as well as a method and a device for detecting an attack on a message sequence transmitted via a data bus.