Tamper resistant circuit boards

DETAILED DESCRIPTION The present invention satisfies this need by means of a physical barrier that also functions as a tampering sensor or sensors monitored by electrical circuitry that generates a tamper signal for erasing information critical for the operation of the circuit board in the event of sensed tampering.
One or more routing matrices configured in at least one programmable device is programmed to interconnect operating as well as optional dummy components on the board so that routing information is erased in the event of sensed tampering.
In accordance with one aspect of the present invention, a tamper resistant circuit board comprises a circuit board having electrically conducting paths and electronic components mounted on the circuit board and interconnected by the electrically conducting paths.
A physical barrier coats the components and the circuit board and has a plurality of layers that are alternately electrically insulating and electrically conducting.
Electrical circuitry is mounted on the circuit board and connected to at least one electrically conducting layer for sensing a tamperer seeking to determine construction or operation of the circuit board and for generating a tamper signal indicative of tampering.
In response to the tamper signal, security circuitry erases information critical for operation of the circuit board.
In accordance with another aspect of the present invention, a tamper resistant circuit board comprises a circuit board having electrically conducting paths with at least one programmable logic component mounted on the circuit board.
Electronic components are mounted on the circuit board and are interconnected by the electrically conducting paths and by programmed paths through the at least one programmable logic component.
A physical barrier coats the at least one programmable logic component, the electronic components and the circuit board with the physical barrier having a plurality of layers which are alternately electrically insulating and electrically conducting