Mechanisms for detecting tampering of an electronic device
First Claim
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1. An electronic device, comprising:
- a chassis;
a printed wiring board (PWB) secured to the chassis by a fastener, the PWB having a pair of conductive traces, and a conductive cap filling electrically insulating gaps between the pair of conductive traces and the fastener to thereby form a conductive path that connects the two traces; and
a sensing circuit coupled to the pair of conductive traces and configured to;
detect a change in impedance of the path, and, in response, signal an alert to a data processor that evaluates and logs tamper events in the electronic device.
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Abstract
An electronic device has a chassis, and a printed wiring board (PWB) having a hole. A fastener is installed in the hole thereby securing the PWB to the chassis. A pair of conductive traces is formed in the PWB. A cap, being an amount of conductive glue, covers a part of the fastener and fills an electrically insulating gap between the two traces, to thereby form a conductive path that connects the two traces. A sensing circuit is coupled to the traces, to detect a change in impedance of the path and signal a tamper event alert. Other embodiments are also described and claimed.
33 Citations
17 Claims
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1. An electronic device, comprising:
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a chassis; a printed wiring board (PWB) secured to the chassis by a fastener, the PWB having a pair of conductive traces, and a conductive cap filling electrically insulating gaps between the pair of conductive traces and the fastener to thereby form a conductive path that connects the two traces; and a sensing circuit coupled to the pair of conductive traces and configured to; detect a change in impedance of the path, and, in response, signal an alert to a data processor that evaluates and logs tamper events in the electronic device. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An electronic device comprising:
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a chassis; a printed wiring board (PWB) secured to the chassis by a plurality of fasteners, wherein, for each fastener, hole the PWB has a respective pair of conductive traces and a respective conductive cap filling electrically insulating gaps between each fastener and each of the respective pair of conductive traces to thereby form a respective conductive path that connects with the respective pair of conductive traces, said respective conductive paths being coupled to each other in series; and a sensing circuit coupled to said respective conductive paths and configured to; detect a change in impedance therein and in response signal an alert to a data processor that evaluates and logs tamper events in the electronic device. - View Dependent Claims (8, 9, 10, 11, 12)
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13. An electronic device comprising:
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a chassis; a printed wiring board (PWB) secured to the chassis by a plurality of fasteners, wherein, for each fastener, the PWB has a respective pair of conductive traces and a respective conductive cap filling electrically insulating gaps between each fastener and each of the respective pair of conductive traces to thereby form a respective conductive path with the respective pair of conductive traces, said respective conductive paths being connected as a randomly accessible sensor array; and a selection and sensing circuit coupled to said randomly accessible sensor array, to pass a current through any one of the respective conductive paths at a time and then detect a change in impedance therein, the selection and sensing circuit configured to, in response to detecting the change in impedance, signal an alert to a data processor that evaluates and logs tamper events in the electronic device, wherein the alert identifies said one of the respective conductive paths in which the impedance change was detected. - View Dependent Claims (14, 15, 16, 17)
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Specification