Dynamic QR Code Display for Replay Attack Prevention
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Solution Overview
Problem
Existing QR codes are vulnerable to replay attacks due to their static nature, and systems that generate changing QR codes require smart devices or connectivity, making them costly, power-intensive, and complex.
Innovation Solution
A QR code display device and method that uses a micro-controller to initialize QR code generation software and an identifier seed, generating a continuously updating QR code for display on a low-powered, inexpensive device without internet connectivity, preventing replay attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a static QR code is used, then the device complexity is low and power consumption is minimal, but the system becomes vulnerable to replay attacks
Solution Approach 1:
The patent implements a dynamic QR code system where the identifier continuously changes over time using a counter variable that increments with each update. This dynamic nature prevents replay attacks while maintaining relatively simple device architecture through a microcontroller that locally manages the counter and generates updated QR codes without external connectivity.
Solution Approach 2:
The system uses self-service by implementing local pseudorandom number generation through a linear feedback shift register (LFSR) circuit within the microcontroller. This eliminates the need for external random number generators or network connectivity, allowing the device to independently generate secure, changing identifiers while keeping the system simple and self-contained.
2Reliability
If a smart device is used to generate changing QR codes, then security against replay attacks is improved, but power consumption and cost increase
Solution Approach 1:
The patent employs a disposable, low-cost microcontroller-based system instead of requiring persistent smart devices. The microcontroller generates changing QR codes locally using simple algorithms (LFSR for pseudorandom numbers and basic counter incrementation), enabling security functionality in inexpensive, low-power devices that do not need smartphone-level processing power or continuous connectivity.
3Reliability
If connectivity to other devices is required for changing QR codes, then security is improved, but the system loses independence and increases complexity
Solution Approach 1:
The patent extracts the security-critical functionality (changing identifier generation) from dependent systems like smartphones or servers and implements it independently within a simple microcontroller. By taking out the pseudorandom number generation and counter management functions and embedding them locally, the system achieves both security and independence without requiring network connectivity or external device interaction.
Data Source
AI summary
A method for displaying a seeded, continuously updating identifier in a QR code and a QR code display and replay attack prevention device that displays a seeded, continuously updating identifier displayed in a QR code are disclosed. This method and QR code display and replay attack prevention device has a changing QR code, preventing replay attacks. The QR code display and replay attack prevention device has a small form factor, is low powered, is inexpensive, and requires no connectivity to the internet.