US 7,270,275 B1 · Secured pin entry device

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.

Claims8

Dependent claims

A tamper detection circuit for a secured key-based entry device for a computer system comprising:

a keypad having a plurality of keycaps that initiate one or more electronic signals when depressed, the signals are used in a computer system;
a frame securing the keypad to the entry device;
a circuit board having electrical contacts that are coupled to a portion of one or more keycaps on the keypad when the keycaps are depressed, the one or more electronic signals are initiated by one or more electrical components on the circuit board based on the particular keycap being depressed;
a tamper detection contact on the circuit board comprising a first conductive pattern and a second conductive pattern, the tamper detection contact initiating a signal when the first and the second conductive patterns are not connected by an electrical switch applied between the first and second patterns;
a third conductive pattern surrounding a predetermined area around the first and second conductive patterns, the third conductive pattern coupled to a predetermined voltage level;
and
a non-conductive moat separating the third conductive pattern and either the first or the second conductive patterns, the non-conductive moat initiating a tamper detection response protocol by a transmission of electrical signals between the third conductive pattern and either the first or second conductive pattern.

4 more elements

Dependencies are inferred from the claim text.

Secured pin entry device

Life of this patent

Secured pin entry device

Life of this patent

Abstract

Claims8