Importance

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Abstract

The invention is a keypad for securely entering personal identification numbers onto automated teller machines (ATM) or similar devices. A frame secures a flexible keypad to a printed circuit board. The front of the circuit includes a set of tamper detection contacts whose electrical circuit is completed by conductive material on the keypad surface. A moat of conductive material surrounds the tamper detection contact. Opening the circuit by removing the keypad or shorting the circuit to the moat initiates a tamper response.Attached to the reverse side of the printed circuit board are security sensitive electrical components. These security sensitive components include a static random access memory storing cryptographic information and a crypto processor. A plastic cover imprinted with a tamper detection grid forming multiple electrical circuits coupled to a tamper detection circuit covers these components. A border of conductive material on the printed circuit board also surrounds these components. Opening or shorting any of the circuits in the grid initiates a tamper response, and shorting any of the components to the border also initiates a tamper response.

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First Claim