Secure PIN entry device

1. A secure PIN entry method comprising:

receiving a PIN from a user at a PIN entry assembly, said PIN entry assembly including a first plurality of key pads and a second plurality of bug sensing floods, electrically insulated from and adjacent to said first plurality of key pads; and

checking at least part of said PIN entry assembly for the presence of an unauthorized PIN eavesdropping element thereat and providing an output indicating whether a predetermined security check has been successfully completed,

said checking comprising employing bug detection circuitry for checking said at least part of said PIN entry assembly for the presence of an unauthorized PIN eavesdropping element thereat,

said employing said bug detection circuitry including:

simultaneously generating an electromagnetic field at at least some of said first plurality of key pads and said second plurality of bug sensing floods; and

sensing mutual capacitance between some of said first plurality of key pads and said second plurality of bug sensing floods and others of said first plurality of key pads and said second plurality of bug sensing floods resulting from said electromagnetic field thereat, said sensing mutual capacitance being operative in a key entry detection mode using autotuning circuitry and in a security scan mode not using autotuning circuitry.

2. The secure PIN entry method according to claim 1 and also comprising in the event of discovery of a bug, providing an output alarm and disabling one or more functions of the PIN entry assembly.

3. The secure PIN entry method according to claim 1 and also comprising case-open detection.

4. The secure PIN entry method according to claim 3 and wherein said case open detection is operative, in the event of a case open condition being detected, to at least one of provide an output alarm and disable one or more functions of the PIN entry assembly.

5. The secure PIN method according to claim 1 and wherein said sensing mutual capacitance, when operative in said security scan mode, combines changes in sensed mutual capacitance of a plurality of elements of said secure PIN entry assembly which exceed a predetermined threshold in order to ascertain whether a bug is present.

6. A secure data entry method comprising:

receiving data from a user at a data entry assembly, said data entry assembly including multiple elements including a first plurality of key pads and a second plurality of bug sensing floods, electrically insulated from and adjacent to said first plurality of key pads;

preventing receipt of said data by said data entry assembly unless a predetermined security check has been successfully completed; and

checking at least part of said data entry method for the presence of an unauthorized data eavesdropping element thereat by sensing mutual capacitance of at least one of said bug sensing floods with at least another element of said data entry assembly and providing an output indicating whether said predetermined security check has been successfully completed, said mutual capacitance sensing being operative in a key entry detection mode using autotuning circuitry and in a security scan mode not using autotuning circuitry.

7. The secure data entry method according to claim 6 and wherein said mutual capacitance sensing, when operative in a security scan mode, combines changes in sensed mutual capacitance of a plurality of elements of said secure data entry assembly which exceed a predetermined threshold in order to ascertain whether a bug is present.

8. The secure data entry method according to claim 6 and wherein said mutual capacitance sensing comprises;

applying a signal to at least some of said first plurality of said key pads;

receiving signals from at least some of said second plurality of bug sensing floods; and

calculating a difference value for each of said at least some of said second plurality of bug sensing floods vis-à-vis a suitably temperature corrected baseline for each of said at least some of said second plurality of bug sensing floods.

9. The secure data entry method according to claim 8 and also comprising comparing a sum of the absolute values of said difference values with a suitable threshold.

10. The secure data entry method according to claim 6 and wherein said mutual capacitance sensing comprises;

applying a signal to at least some of said first plurality of said key pads;

receiving signals from at least others of said first plurality of key pads; and

calculating a difference value for each of said others of said first plurality of key pads vis-à-vis a suitably temperature corrected baseline for each of the floods.

11. The secure data entry method according to claim 10 and also comprising comparing a sum of the absolute values of said difference values with a suitable threshold.

12. The secure data entry method according to claim 6 and wherein said mutual capacitance sensing comprises;

simultaneously applying a signal to at least some of said second plurality of said bug sensing floods;

receiving signals from at least some of said first plurality of key pads; and

calculating a difference value for each of said some of said first plurality of key pads vis-à-vis a suitably temperature corrected baseline for each of the some of said first plurality of key pads.

13. The secure data entry method according to claim 12 and also comprising comparing a sum of the absolute values of said difference values with a suitable threshold.

14. The secure PIN entry method according to claim 3 and also comprising mutual capacitance sensing applied to elements of case-open switches.

15. The secure PIN entry method according to claim 1 and wherein at least one of said second plurality of bug sensing floods comprises a mesh.