Transaction device with noise signal encryption

• US 20040064711A1
• Filed: 03/07/2003
• Published: 04/01/2004
• Est. Priority Date: 03/07/2002
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Fernando, Llavanya, Wang, Nathan C., Soysa, G.F.R. Sulak
• Granted Patent: US 7,392,396 B2
• Time in Patent Office: Days
• US Class Current: 713/189
• CPC Class Codes: G06F 21/83 input devices, e.g. keyboards, mice or controllers thereof
• CPC Class Codes: G06Q 20/20 Point-of-sale [POS] network systems

Abstract

A transaction device adds or injects a random noise component into signals representing (x,y) coordinate signals associated with user interface with an input screen associated with the device. The noise component can be generated by converting to analog the output of a random number generator, and then adding the noise component to the x-axis and/or y-axis component of the (x,y) coordinate signal. Alternatively the noise component can be injected into the x-axis and/or y-axis operating potential for the input screen. The result is a masking of the original (x,y) positional information. The randomly generated number is only available internal to the device. The device can use this number to de-crypt the true (x,y) signals, which signals can then be re-encrypted before transmitting from the device.

Claims

1. A transaction device to receive user-input data on at least one (x,y) location on a user-interfaceable surface, and to internally encrypt signals proportional to said (x,y) location, the transaction device comprising:

a user-interfaceable surface, coupled to at least one source of potential so as to output x-axis and to y-axis (x,y) location signals proportional to user interface with locations on said user-interfaceable surface;

means for generating a random signal; and

means for adding said random signal to at least one of said x-axis location signals and said y-axis location signals;

wherein at least one of said x-axis and said y-axis location signals are encrypted.

2. The transaction device of claim 1, further including electronics, housed within said transaction device, comprising at least one of said means for generating and said means for adding.

3. The transaction device of claim 1, further including:

a processor;

a screen controller coupled to said processor and to said user-interfaceable surface;

wherein said processor is also coupled to receive said random signal and to de-encrypt at least one of said x-axis and said y-axis location signals.

4. The transaction device of claim 3, further including:

means for encrypting de-encrypted said location signals; and

means for outputting encrypted said location signals from said transaction device.

5. The transaction device of claim 1, wherein said means for generating includes:

a random digital signal generator; and

digital-to-analog converter coupled to receive output from said random digital signal generator;

wherein an output from said digital-to-analog converter is said random signal.

6. The transaction device of claim 1, wherein said means for adding directly adds said random signal to at least one of said x-axis signal and said y-axis signal.

7. The transaction device of claim 1, wherein said means for adding injects said random signal into at least one said source of potential.

8. The transaction device of claim 1, wherein said user-interfaceable surface is a display-input screen that can output information from said transaction device and can respond to user-interface.

9. The transaction device of claim 1, wherein said user-interfaceable surface comprises a resistive film response to a change in pressure exerted by a user of said transaction device.

10. The transaction device of claim 1, wherein said user-interfaceable surface is responsive to heat associated with user-interface with said transaction device.

11. The transaction device of claim 1, wherein said user-interfaceable surface comprises material responsive to pressure exerted with user-interface with said transaction device.

12. The transaction device of claim 1, wherein said user-interfaceable surface is responsive to changes in light resulting from user-interface with said transaction device.

13. The transaction device of claim 1, wherein said user-interfaceable surface is responsive to infrared energy resulting fro user-interface with said transaction device.

14. A method of encrypting signals proportional to (x,y) locations on a user-interfaceable surface on a transaction device, the method comprising the following steps:

(a) receiving from said user-interfaceable surface at least one of x-axis and y-axis location signals proportional to locations of user interface with said user-interfaceable surface;

(b) generating a random signal;

(c) adding said random signal to at least one of said x-axis and y-axis location signals;

wherein location signals received at step (a) are encrypted by said random signal.

15. The method of claim 14, wherein step (b) is carried out before step (a).

16. The method of claim 14, wherein step (c) includes adding said random signal to a source of operating potential for at least one source of potential for x-axis and y-axis operation of said user-interfaceable surface.

17. The method of claim 14, wherein said user-interfaceable surface is a display-input screen that can output information from said transaction device and can respond to user-interface.

18. The method of claim 14, wherein step (b) includes:

generating a random number; and

converting said random number to an analog signal used as said random signal.

19. The method of claim 14, wherein said method is carried out by electronics disposed within a housing of said transaction device.

20. The method of claim 14, further including:

disposing within a housing of said transaction device electronics carrying out said method;

said electronics including at least a screen controller and a processor;

said processor coupled to said screen controller, and said screen controller coupled to said user-interfaceable surface;

coupling said digital signal to said processor;

wherein said processor can de-encrypt at least one of encrypted said x-axis and y-axis signals.