Circuit Data Integrity Checking with Obfuscated CRC Verification
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Solution Overview
Problem
Data integrity is compromised during transmission between electronic cartridges due to the lack of inline authentication and message authentication code protection on communication buses, allowing malicious modifications to go undetected.
Innovation Solution
A system and method that generate and verify packages with headers, payload data, and footers using cyclic redundancy checks (CRC) with obfuscation techniques such as random selection of CRC variants, nonsequential paths, and incorporation of random numbers, along with message authentication codes, to ensure data integrity and detect intentional modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If message authentication code protection is applied to entire packet payloads, then data integrity is improved, but communication performance deteriorates due to processing overhead
Solution Approach 1:
The patent segments the data protection approach by applying different authentication mechanisms to different parts of the data stream. Message authentication codes are applied selectively to critical header fields and footer fields rather than entire packet payloads, while cyclic redundancy checks provide lighter-weight protection for other data portions. This segmentation allows strong integrity protection where needed while maintaining high communication performance for bulk data transfer.
Solution Approach 2:
The patent implements local quality by applying different levels of authentication strength to different regions of the data structure. Critical fields such as headers containing routing information and footers containing control information receive full message authentication code protection, while the bulk payload data receives lighter CRC protection. This localized approach ensures data integrity for critical elements without sacrificing overall communication performance.
2Reliability
If inline authentication hardware is added to the bus, then data integrity is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements self-service by enabling transmitting and receiving cartridges to perform authentication functions using their own processing resources rather than requiring dedicated inline authentication hardware on the bus itself. The transmitter calculates message authentication codes and cyclic redundancy checks using its own processor, and the receiver verifies these values using its own processing capabilities. This approach improves data integrity while avoiding the added complexity and cost of specialized authentication hardware on the communication bus.
3Reliability
If cryptographic protection is applied to all data, then security against malicious modification is improved, but processing time and energy consumption increase
Solution Approach 1:
The patent applies partial action by implementing cryptographic protection only for critical portions of the data rather than all data. Message authentication codes are calculated over header and footer fields that contain control and routing information, while the bulk payload data is protected with faster cyclic redundancy checks. This selective approach provides adequate security against malicious modification of critical fields while minimizing processing time and energy consumption for the overall data transmission.
Data Source
AI summary
An apparatus has a communication bus, a first circuit, and a second circuit. The first circuit is operational to generate a package, calculate a check value of payload data in the package with a particular cyclic redundance check variant and an obfuscation type, store an encrypted check value in a footer of the package, store an encrypted obfuscation code in a header of the package, and transmit the package on the communication bus. The second circuit is operational to receive the package from the communication bus, decrypt the encrypted check value to determine the check value calculated by the first circuit, determine an obfuscation type from the encrypted obfuscation code, perform a payload verification of the payload data with the particular cyclic redundancy check variant with the obfuscation type applied and the check value, and signal that the payload data is valid in response to passage of the payload verification.