Capacitive Keypad Security Device Using Parasitic Capacitance Simulation
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Solution Overview
Problem
Current electronic payment terminals with capacitive keyboards lack effective solutions to protect sensitive data from hacking, as 'spy' systems can intercept key presses by measuring signal levels, and existing security measures like guard rings do not adequately address these issues.
Innovation Solution
A security device for capacitive keyboards that simulates random key presses, using a control module and parasitic capacitance to disrupt spying systems while maintaining normal operation, by connecting parasitic capacitance to receiving electrodes upon receipt of simulation commands from the processor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a capacitive keyboard is used in electronic payment terminals, then the ease of operation is improved, but the security against spying is worsened
Solution Approach 1:
The security device activates simulation elements before actual key presses occur, generating fake电容ive signals that preemptively confuse potential spy systems. The processor randomly triggers these simulation elements during periods when no user input is expected, establishing a baseline of artificial activity that makes subsequent real key presses indistinguishable from simulations.
Solution Approach 2:
The security device introduces an intermediary layer between the user's physical key presses and the terminal's processing system. By injecting simulated key press signals through the same capacitive sensing mechanism, it creates a mixed signal environment where real and fake inputs are combined, preventing spy systems from reliably detecting actual user actions.
2Object-affected harmful factors
If simulation elements are activated to prevent spying, then the security is improved, but the risk of disturbing normal key management is worsened
Solution Approach 1:
The security device establishes a communication channel with the processor to receive feedback about actual key press events. The processor informs the security device when real key presses occur, allowing the simulation elements to be temporarily deactivated or adjusted during active input periods, ensuring that normal key management operations remain reliable and uninterrupted.
Solution Approach 2:
The security device dynamically adjusts its simulation activity based on system state. Simulation elements are activated during idle periods to maintain security, but deactivated or modified when the processor indicates active key management operations are occurring, allowing the system to adapt between security mode and operational mode.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents data interception by simulating key presses that confuse spying devices, ensuring the security of sensitive data entry without disturbing the terminal's key management process.
Implementation Method 1
the simulation element (S) implements at least one capacitance (CP1) of a predetermined value, called parasitic capacitance
Data Source
AI summary
The invention relates to a security device for a capacitive keypad of an electronic payment terminal, comprising at least one key management processor for said capacitive keypad. According to the invention, such a security device is capable of communicating with said processor and comprises a control module for at least one simulation element for at least one key press on said capacitive keypad, said control module comprising means for receiving at least one simulation command (Cmd1, Cmd2) transmitted randomly by said processor. Said simulation element implements at least one capacitance (CP1, CP2) of a predetermined value, referred to as a parasitic capacitance, said control module triggering said parasitic capacitance (CP1, CP2) by closing at least one switch.