Patent ID: 7784691

Claim:
A magnetic card reader comprising: a protected enclosure; a magnetic head having at least one signal output, said magnetic head being located outside said protected enclosure; at least one signal path extending from said magnetic head outside said protected enclosure to a location inside of said protected enclosure and carrying said at least one signal output; signal processing circuitry located inside of said protected enclosure and receiving said at least one signal output along said at least one signal path; and anti-tapping functionality comprising: an obscuring signal injector located inside of said protected enclosure and coupled to said at least one signal path at said location within said protected enclosure, said obscuring signal injector being operative to apply an obscuring signal to said at least one signal path, such that the signal that appears on said at least one signal path is a combination of said at least one signal output and said obscuring signal; and an obscuring signal remover located within said protected enclosure and coupled to said at least one signal path at said location within said protected enclosure, for receiving said combination of said at least one signal output and said obscuring signal and for providing an unobscured signal output, corresponding to said at least one signal output, to said signal processing circuitry.