Integrated Circuit GPIO Status Querying Without Physical Access
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Solution Overview
Problem
The current status of digital signal pins in integrated circuits, such as GPIO pins, cannot be assessed in a standardized way via an Application Protocol Data Unit (APDU), preventing readout devices from detecting manipulations or triggering actions based on these pins.
Innovation Solution
A method and integrated circuit that allow obtaining and using the current status of digital signal pins internally within the integrated circuit and externally via a readout device without physical access, using a software object to request and return the status from the operating system, and perform actions based on it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPIO pins are made internally inaccessible to prevent external manipulation, then security is improved, but the ability to detect manipulations via external measurement is lost
Solution Approach 1:
The patent introduces an intermediary software object that acts as a mediator between the external readout device and the internal GPIO pins. The software object receives requests from the readout device, queries the operating system for GPIO status, and returns the information without requiring physical access to the pins. This resolves the contradiction by maintaining security (pins remain internally protected) while enabling detection (status can be queried through the software intermediary).
Solution Approach 2:
The patent replaces the mechanical/physical measurement approach (using an oscilloscope to measure pins externally) with a software-based information retrieval system. Instead of physically accessing and measuring the GPIO pins, the system uses software objects and operating system interfaces to obtain the status information digitally. This substitution eliminates the need for physical access while maintaining the ability to detect GPIO status.
2Ease of operation
If a standardized protocol is implemented to query GPIO status via APDU, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal software object interface that can query multiple GPIO pins through a single standardized mechanism. The software object is designed to handle requests for any GPIO pin using the same APDU protocol structure, making the system easy to operate. While the underlying software architecture has complexity, the interface presents a simple, unified method for querying GPIO status that can be used consistently across different pins and scenarios.
3Measurement precision
If external measurement of GPIO pins is performed to detect manipulations, then manipulation detection capability is improved, but physical access to pins is required which compromises security
Solution Approach 1:
The software object serves as a secure intermediary that enables manipulation detection without physical access. It retrieves GPIO status information through authorized software interfaces, allowing the readout device to detect manipulations (such as unauthorized changes to GPIO states) while maintaining the physical security of the smart card. The intermediary provides the necessary measurement capability without exposing the system to physical access risks.
Data Source
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AI summary
Disclosed herein is a method (100) for obtaining and/or using a current status of a digital signal pin (11) of an integrated circuit (10). The method (100) comprises sending (103), by a software object (14) installed within the integrated circuit (10), a request for a current status of at least one digital signal pin (11) of the integrated circuit (10) to an operating system (13) of the integrated circuit (10). The method further comprises returning (104), by the operating system (13), the current status of the at least one digital signal pin (11) requested by the software object (14) to the software object (14), and performing (105), by the software object (14), an action based on the current status of the obtained at least one digital signal pin (11). Further, an integrated circuit (10), which may (for example) be a smart card such as a payment card or an electronic identification card, is disclosed. The integrated circuit (10) comprises at least one digital signal pin (11) (such as a GPIO pin), a software object (14) (such as an applet), and an operating system (13). The integrated circuit (10) is configured for carrying out the disclosed method (100).