CAN Transceiver Glitch Detection and Frame Invalidation
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Solution Overview
Problem
In Controller Area Network (CAN) bus systems, malicious devices can hijack bus control by introducing signal glitches, which existing transceivers fail to detect and prevent, leading to data corruption and security breaches.
Innovation Solution
A transceiver configured to detect signal glitches in predetermined portions of data frames and invalidate them by sending a CAN error message or disabling the transmitter, using a clock recovery and sampling circuit to monitor bit timings and amplitudes, and generate an invalidation signal to prevent malicious interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a typical transceiver provides ISO 11898 standard compliant communication without scrutinizing data content, then communication speed and simplicity are improved, but security and reliability deteriorate due to inability to detect signal glitches
Solution Approach 1:
The transceiver performs preliminary actions by monitoring signal parameters (rise time, fall time, voltage levels) during the transmission process to detect potential glitches before they can corrupt data. The system proactively identifies abnormal signal characteristics that indicate malicious interference attempts, allowing preventive response before complete data corruption occurs.
Solution Approach 2:
The transceiver implements feedback mechanisms by continuously monitoring the transmitted signal and comparing actual signal parameters against expected values. When deviations indicating glitches are detected, the system generates feedback signals to invalidate the data frame and notify the microcontroller, creating a closed-loop security system that responds to detected threats.
2Reliability
If the transceiver monitors signal parameters and detects glitches, then security is improved, but device complexity increases due to additional monitoring circuits and processing requirements
Solution Approach 1:
The transceiver achieves multi-functionality by integrating multiple functions into a single device: standard CAN bus communication, signal parameter monitoring, glitch detection, and invalidation handling. The same hardware circuits that handle normal data transmission also perform security monitoring functions, eliminating the need for separate dedicated security hardware and reducing overall system complexity.
Solution Approach 2:
The system manages complexity by monitoring a limited set of critical signal parameters (rise time, fall time, voltage levels) rather than analyzing every aspect of the signal. By focusing on key parameters that indicate glitch conditions, the transceiver achieves effective security monitoring with minimal additional computational overhead and circuit complexity.
3Reliability
If the transceiver invalidates data frames and disables transmitter upon glitch detection, then data integrity is improved, but communication productivity decreases due to transmission interruptions
Solution Approach 1:
The system converts the harmful effect of detected glitches into beneficial security actions by automatically invalidating compromised data frames and disabling the transmitter to prevent further malicious transmission. This transforms the detection event from a mere signal into an active security response that protects the network, using the glitch detection capability to eliminate threats rather than simply reacting to them.
Solution Approach 2:
The transceiver applies partial action by invalidating only the specific data frame containing the glitch rather than shutting down all communications. The system selectively responds to the problematic transmission while maintaining normal operation of other nodes, thereby minimizing productivity impact while achieving the necessary security response.
Data Source
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AI summary
A transceiver for sending and receiving data from a controller area network (CAN) bus is disclosed. The transceiver includes a microcontroller port, a transmitter and a receiver, wherein the transceiver is configured to determine bit timings from a data frame received by the receiver. The transceiver is further configured to detect attempts to introduce a signal glitch in a predetermined portion of the data frame and upon detection of the signal glitch, the transceiver is configured to invalidate the data frame on a transmission line and/or disable the transmitter for a predetermined period.