Secure Keypad Using Optical Detection and Conductive Shielding
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Solution Overview
Problem
Existing keypad systems in secure environments, such as ATMs, face challenges in protecting user input, like PINs, from unauthorized detection due to increasing sensitivity and coverage area requirements of tamper-detecting grids, leading to rising costs.
Innovation Solution
A touch-sensitive keypad system with force sensors and a conductive, pliable casing that encloses all electronic components, ensuring that only mechanical parts are outside, and all electrical signals are contained and encoded or encrypted, preventing signal leakage and enhancing security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tamper-detecting grids are made more sensitive and cover larger areas to protect PIN input, then security against unauthorized access is improved, but cost increases
Solution Approach 1:
The patent replaces the mechanical/electrical tamper-detecting grid system with an optical detection system using a camera and image processing. The camera captures images of the keypad, and software algorithms detect finger positions and PIN input patterns, eliminating the need for expensive and complex electromagnetic shielding grids while maintaining security.
2Ease of operation
If electrical signals are used to sense the keyboard, then input detection is enabled, but signals may be detected by unauthorized persons
Solution Approach 1:
The patent replaces electrical signal sensing with optical sensing. Instead of using electrical circuits that can be tapped or monitored, the system uses a camera to capture optical images of the keypad surface. The position and pressure of finger inputs are determined by analyzing changes in the optical image, thereby eliminating electromagnetic signal leakage vulnerabilities.
Solution Approach 2:
The patent introduces an optical intermediary (camera and light field) between the user input and the detection system. The camera acts as a mediator that converts physical finger pressure and position into optical images, which are then processed to detect PIN input. This intermediary layer prevents direct electrical signal exposure while maintaining detection capability.
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
This solution effectively shields electromagnetic interference and prevents unauthorized detection of user inputs by encoding signals within the conductive casing, enhancing the stability and reliability of the keypad system while maintaining high security standards.
Implementation Method 1
An electrically conductive, force transmissive, pliable casing encloses the force sensors, the identification means and the generating means... it is ensured that no electrical or electro-magnetic signals relating directly the user's operation of the keypad escape the casing
Implementation Method 2
A plurality of force sensors are coupled to the screen and arranged at individual force sensor locations to sense individual forces in response to the screen being touched and to generate corresponding individual force signals
Data Source
Figure 1
Figure 2~3
AI summary
A secure keypad system has a touch sensitive screen (11) with a plurality of distinct fields (12) on a surface, where each field (12) has an associated input value. A plurality of force sensors (16, 17) are coupled to the screen (11) and arranged at individual force sensor locations to sense individual forces in response to the screen (11) being touched and to generate corresponding individual force signals. Identification means are provided for identifying a field (12) being touched based on the force signals, and generating means are provided for generating the input value associated with the field (12) being touched. An electrically conductive, force transmissive casing (20) encloses the force sensors, the identification means and the generating means.