Microcontroller Power Supply Authentication With Encrypted Tamper Mode
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Solution Overview
Problem
Microcontrollers, such as system on a chip (SoC) devices, are vulnerable to malicious attacks through tampering with the power supply, which can lead to unauthorized access or misbehavior by using a malicious power supply that mimics the genuine one, especially during communication.
Innovation Solution
A microcontroller with a first integrated circuit configured to receive power from a power supply via at least one power input terminal and communicate with it through at least one communication terminal, using encrypted communication based on a pre-shared encryption key for authentication. If the power supply passes authentication, the microcontroller operates in normal mode; otherwise, it enters a tamper mode with reduced functionality until authentication is successful, and it can request changes in power using encrypted communication to verify the power supply's authenticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encrypted communication and authentication protocols are implemented between microcontroller and power supply, then security against malicious attacks is improved, but device complexity increases
Solution Approach 1:
Authentication credentials and encryption keys are pre-configured in both the microcontroller and power supply during manufacturing. This preliminary action eliminates the need for complex runtime key exchange protocols, reducing communication complexity while maintaining security.
Solution Approach 2:
The authentication protocol uses challenge-response feedback mechanisms where the microcontroller sends authentication requests and the power supply provides verified responses. This structured feedback loop ensures security while maintaining manageable communication complexity through defined interaction patterns.
2Reliability
If the microcontroller continuously monitors power supply authentication status, then detection of malicious power supplies is improved, but loss of time for normal operations increases
Solution Approach 1:
Authentication is performed preliminarily during system initialization and power-up sequences. This preliminary authentication establishes trust before normal operations begin, eliminating the need for continuous verification during critical operations and reducing time loss.
Solution Approach 2:
The system implements periodic authentication monitoring at predetermined intervals rather than continuous monitoring. This periodic approach maintains detection capability while minimizing interference with normal operations and reducing overall time loss.
3Reliability
If the microcontroller enters tamper mode upon authentication failure, then protection against malicious attacks is improved, but productivity decreases
Solution Approach 1:
The system dynamically adjusts operational modes based on authentication status. Normal mode provides full productivity when authentication succeeds, while tamper mode provides enhanced protection when authentication fails. This dynamic switching resolves the contradiction by making protection level and productivity context-dependent rather than fixed.
Solution Approach 2:
The system changes operational parameters (functionality level, access rights, operational constraints) when transitioning between normal and tamper modes. These parameter changes enable the system to maintain high productivity during normal operation while providing strong protection when needed, resolving the contradiction between protection level and operational availability.
Data Source
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AI summary
A microcontroller comprising a first integrated circuit configured to receive power from a power supply comprising a second integrated circuit via at least one power input terminal and wherein at least one communication terminal provides for communication between the microcontroller and the power supply, wherein the microcontroller is configured to provide for encrypted communication between the power supply and the microcontroller based on a pre-shared encryption key, the encrypted communication configured to provide for authentication of the identity of the power supply and, if the power supply passes the authentication, the microcontroller is configured to operate in a normal mode and receive said power from the power supply, and if the power supply fails authentication, the microcontroller is configured to enter a tamper mode.