Magnetic Recording Security via Dynamic Interference Field Generation
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Solution Overview
Problem
Existing magnetic recording medium processing devices are vulnerable to fraudulent reading due to interference magnetic fields generated in identical waveforms, which can be analyzed by skimming heads, despite previous technologies using resonance circuits with coils and capacitors.
Innovation Solution
A magnetic recording medium processing device with an interference magnetic field generating device that includes a coil, capacitor, and multiple switches, where the switch control unit alternates between series and reverse-polarity connections to generate different interference magnetic fields, making it difficult for skimming heads to analyze them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resonance circuit with coil and capacitor is used to generate interference magnetic field, then the interference magnetic field can be generated, but the waveform is identical and can be analyzed by skimming head
Solution Approach 1:
The patent applies dynamics by making the interference magnetic field generation mode switchable between series resonance and reverse polarity configurations. The control unit dynamically changes the circuit configuration based on operation mode signals, transforming a static resonance circuit into a dynamic system that adapts its characteristics to prevent analysis by skimming heads while maintaining security effectiveness.
Solution Approach 2:
The patent changes the electrical parameters of the interference field generation circuit by switching between series connection (for resonance) and reverse polarity connection (for different waveform characteristics). This parameter change approach modifies the magnetic field waveform properties without adding complex hardware, resolving the contradiction between security reliability and device complexity.
2Object-affected harmful factors
If series resonance connection is used between coil and capacitor, then interference magnetic field is generated, but the waveform remains identical across operations
Solution Approach 1:
The patent implements periodic action by alternating between series resonance mode and reverse polarity mode based on control signals. This periodic switching creates variable waveforms in the interference magnetic field over time, preventing skimming heads from analyzing a single static waveform pattern while maintaining continuous interference effectiveness.
Solution Approach 2:
The patent applies inversion by using reverse polarity connection as an alternative to the conventional series resonance connection. This inverted approach connects the coil and capacitor in reverse polarity through switches, generating interference magnetic fields with different waveform characteristics that are difficult to analyze, thereby improving adaptability while maintaining security effectiveness.
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
The device effectively prevents fraudulent reading by generating difficult-to-analyze interference magnetic fields, enhancing security by varying the magnetic fields' characteristics.
Implementation Method 1
an interference magnetic field is generated by a parallel resonance caused between a coil and a capacitor
Implementation Method 2
a coil (411), a capacitor (412), a first power line (46), a second power line (47) to which a voltage different from that to the first power line is applied
Data Source
AI summary
A magnetic recording medium processing device may include a magnetic recording medium insertion slot; a medium pathway connected to the magnetic recording medium insertion slot; a magnetic head arranged to face the medium pathway; and an interference magnetic field generating device structured to generate interference magnetic fields outside the magnetic recording medium insertion slot. The interference magnetic field generating device may include a coil, a capacitor, a first power line, a second power line to which a voltage different from that to the first power line is applied, multiple switches structured to switch the connections between the first power line and the second power line of the coil and the capacitor, and a switch control unit structured to control the multiple switches.