Hardware-Read Storage Circuit for Secure Configuration Checking
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Solution Overview
Problem
Existing automotive electronic systems face challenges in integrating functional safety and cybersecurity effectively, as they are typically designed with functional safety first and then adding cybersecurity afterwards, leaving a window of vulnerability without initial protection.
Innovation Solution
A storage circuit design that inherently combines functional safety and cybersecurity through a two-step or three-step configuration process, where new configuration data is written and its bit-wise inverted version is also written, allowing error detection without software read access, and includes features for authenticity and confidentiality, using cascaded flip-flops and comparators to generate error signals for fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If configuration data is written and read back by software for verification, then functional safety is improved through error detection, but cybersecurity is worsened due to exposure of configuration data and extended attack window
Solution Approach 1:
The patent extracts the read access functionality from the software domain and relocates it to the hardware domain. Configuration data is written by software but read only by hardware circuits (comparators and storage elements), eliminating software exposure to configuration data while maintaining functional safety through hardware-based verification
Solution Approach 2:
The patent introduces hardware comparators as intermediaries between the configuration data and verification processes. These comparators directly compare written data with inverted data in hardware, eliminating the need for software to read and verify configuration data, thus protecting cybersecurity while ensuring functional safety
2Reliability
If configuration data is stored with both original and inverted versions for error detection, then functional safety is improved through fault detection capability, but device complexity increases due to additional storage requirements
Solution Approach 1:
The patent merges the storage of original configuration data and inverted configuration data into a single storage circuit element. The same hardware structure stores both versions simultaneously, eliminating the need for separate storage components and reducing overall device complexity while maintaining error detection capability
Solution Approach 2:
The storage circuit element is designed to serve multiple functions: storing original configuration data, storing inverted configuration data, and providing both to hardware comparators for verification. This multi-functionality reduces the need for additional dedicated components, thereby reducing device complexity
Data Source
AI summary
A method for configuring a storage circuit, including: writing data via an input line into the storage circuit by a software write access; writing a bit-wise inverted form of the data via the input line into the storage circuit by a subsequent software write access; and generating an error signal if a comparison based on the written data and the written bit-wise inverted form of the data indicates a storage circuit configuration error, wherein the storage circuit permits hardware read access and lacks software read access.