Method and apparatus for verifying the integrity of a smart card
First Claim
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1. A method of verifying the integrity of a card under test having exterior contact terminals and on-board electronic circuitry containing coded data to be read in a host reader, comprising the steps of:
- detecting capacitance of wires connecting the card under test to the host reader, applying a signal to the card under test, and comparing-a current result of the signal on a detector with a previous result obtained from a genuine and authorized card to establish whether the card under test is genuine.
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Abstract
A Contact Smart Card (3) is inserted in a contact card reader and its capacitance is measured by applying a square wave generated by an oscillator (1) to it via a resistor (4). The capacitance effect of the smart card (3) affects the amplitude of the output from the resistor (1) and the output is monitored in an amplitude detector (2) connected to receive the signal output from the resistor (4) and to compare it against a threshold level for the signal previously established and stored for an acceptable card.
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Citations
8 Claims
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1. A method of verifying the integrity of a card under test having exterior contact terminals and on-board electronic circuitry containing coded data to be read in a host reader, comprising the steps of:
- detecting capacitance of wires connecting the card under test to the host reader, applying a signal to the card under test, and comparing-a current result of the signal on a detector with a previous result obtained from a genuine and authorized card to establish whether the card under test is genuine.
- View Dependent Claims (2, 3, 4, 5, 6)
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7. A method according to claim 7, including accepting the card under test as genuine if the capacitance of the card under test is measured as being below a threshold level.
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8. Apparatus for verifying the integrity of a card under test having exterior contact terminals and on-board electronic circuitry containing coded data to be read in a host reader, comprising:
- means for detecting capacitance of wires connecting the card under test to the host reader, means for applying a signal to the card under test, and means for comparing a current result of the signal on the detecting means with a previous result obtained from a genuine and authorized card to establish whether the card under test is genuine.
Specification