I2C Communication Timing Checks for Condition Tampering
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Solution Overview
Problem
Existing serial communication methods like I2C struggle to detect abnormalities in signal patterns, particularly when tampering occurs, making it difficult to ensure functional safety and security, especially when cyclic redundancy codes or message authentication codes fail to identify changes in start and end positions of data transmission.
Innovation Solution
Implementing time constraints on the Low and High periods of the clock signal after data transmission to detect abnormalities in the condition portions of I2C communication, using a communication device with a detection unit to monitor these constraints and identify any tampering or attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CRC or MAC is used for detecting abnormalities in I2C communication, then data integrity can be verified, but abnormalities in the condition portion (start/end positions) cannot be detected
Solution Approach 1:
The patent divides the I2C communication into two distinct portions: the data portion (where CRC/MAC can be applied) and the condition portion (start/end positions). By segmenting the communication protocol this way, the invention enables separate detection mechanisms for each portion, allowing condition portion tampering to be detected through timing analysis independent of the data integrity checks.
Solution Approach 2:
The patent introduces timing information as an intermediary element between the condition portion and the data portion. The timing constraints serve as a mediator that can detect abnormalities in the condition portion without interfering with the data transmission itself. This intermediary timing mechanism allows the system to verify condition integrity separately from data integrity.
2Reliability
If time constraints are added to detect abnormalities in condition portion, then detection capability improves, but device complexity increases
Solution Approach 1:
The patent changes the detection parameter from data-based (CRC/MAC) to timing-based for the condition portion. By using timing constraints (measuring the duration of start and end conditions) rather than adding complex data verification algorithms, the invention achieves detection capability with minimal increase in device complexity. The timing measurement function can be implemented using existing timers or counters in the communication device.
Data Source
AI summary
The present technology relates to a communication device, a communication method, and a program that enable detection of abnormality of data in a signal portion of a predetermined pattern of serial communication. A communication device of the present technology performs I2C communication with an external communication device serving as a master, and detects an abnormality in a signal portion of a predetermined pattern generated by the external communication device on the basis of at least one of a first time constraint set for a Low period or a second time constraint set for a High period of a clock signal after completion of transmission of a response signal subsequent to data. The present technology can be applied to an image sensor.