Tamper Detection Using Passive Tag Resonant Frequency
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Solution Overview
Problem
Current tamper detection systems, such as capacitive sensing devices, are unreliable in detecting non-native hardware due to interference from raindrops and human presence, making them ineffective in preventing card skimming fraud at devices like ATMs.
Innovation Solution
A tamper detection system that uses a tag adjacent to the device, transmitting signals and setting an alarm condition when no or incorrect reply signals are received, with frequency response data comparison to reference data to ensure authenticity, utilizing wireless communication circuitry and antennas to detect foreign objects or tampering attempts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitive sensing devices are used to detect skimmers, then tamper detection capability is provided, but false alarms occur due to interference from raindrops and human presence
Solution Approach 1:
The patent introduces a tag as an intermediary element attached to the device, which mediates between the reader and the environment. The tag's resonant frequency response serves as a stable reference that is not affected by external factors like rain or human presence, thereby resolving the false alarm problem while maintaining tamper detection capability
Solution Approach 2:
The patent shifts from measuring capacitive changes (which are sensitive to environmental factors) to measuring resonant frequency response of a tag (which provides a stable reference). This parameter change from capacitance to resonant frequency eliminates the interference from raindrops and human presence while maintaining reliable tamper detection
2Reliability
If a tag with wireless communication circuitry is used, then accurate tamper detection is achieved, but device complexity increases
Solution Approach 1:
The tag is a passive element that does not require its own power source. It is energized by the magnetic field generated by the reader during normal card reading operations, and it automatically provides its resonant frequency response for tamper detection. This self-service approach enables accurate tamper detection without adding active components or power requirements to the system
Solution Approach 2:
The tag serves multiple functions: it acts as both a card reading target (interacting with the magnetic reader) and a tamper detection element (providing resonant frequency response). This multi-functionality reduces overall system complexity by combining card reading and security functions into a single simple passive component
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
Provides a robust and reliable method to detect tampering attempts, minimizing false alarms and ensuring secure operations at devices like ATMs by accurately identifying non-native hardware, even in adverse conditions like rain.
Implementation Method 1
transmitting a signal to a tag adjacent a device susceptible to tampering
Implementation Method 2
Tag 30 receives a continuous wave signal from reader 20 and reflects the continuous wave signal back to reader 20 using a technique known as backscattering
Implementation Method 3
Wireless communication circuitry 24 demodulates reply signals from tag 30 and may additionally determine frequency response data, including amplitude and/or phase differences between reader and tag signals
Data Source
AI summary
A tamper detection system and method which uses a reader and one or more tags to detect tampering near a card reader slot or any other device subject to tampering. An example tamper detection method includes transmitting a signal to a tag adjacent a device susceptible to tampering, and setting an alarm condition when no reply signal or an incorrect reply signal is received in response to the signal.