Electromagnetic field tamper alarm

• US 6,553,497 B1
• Filed: 03/25/1999
• Issued: 04/22/2003
• Est. Priority Date: 03/25/1999
• Status: Expired due to Fees

• Current Assignee: Lenovo Singapore Pte Limited (Lenovo Group Ltd.)
• Original Assignee: International Business Machines Corporation
• Inventors: Challener, David C., Atkins, Barry D.
• Primary Examiner(s): HUA, LY
• Application Number:
  US09/275,753
• Time in Patent Office: 1,489 Days
• Field of Search: 713/200, 713/201, 713/193, 340/5.32, 340/5.33, 340/5.5, 340/5.74, 340/531, 340/539, 340/568, 340/568.3, 340/569, 340/572.1, 340/572.8, 340/635, 340/657, 340/658, 340/660, 340/825.36, 380/25, 361/111, 361/56, 361/58
• US Class Current: 726/23
• CPC Class Codes: G06F 21/84 output devices, e.g. displays or monitors
• CPC Class Codes: G06F 21/86 Secure or tamper-resistant housings

Abstract

The present invention is a method and system for providing a tamper alarm for a computer system. The method includes detecting tampering of the computer system, and transmitting electromagnetic field signals from a device concerning the tampering. In the preferred embodiment, the electromagnetic field signals are transmitted through patterns on a monitor or a video card which transmits a computer system identity information. The electromagnetic field signal of the present invention functions as a tamper alarm. When a receiver hears the alarm, the administrator of the computer system may act accordingly. The tamper evidence alarm may be transmitted in a manner which does not require the disabling of the computer system, thus increasing the ease of its use over conventional methods. Because the computer system is not disabled, a password is not required in order to regain access to the computer system. Also, the present invention may be practiced using existing hardware in the computer system, and thus is cost efficient to implement.

Claims

1. A method comprising the steps of:

(a) detecting tampering of a computer system; and

(b) transmitting electromagnetic field signals from a device concerning the tampering wherein said transmitting step comprises creating patterns by a video card to transmit a computer system identity information.

2. A method comprising the steps of:

(a) detecting tampering of a computer system; and

(b) transmitting electromagnetic field signals from a device concerning the tampering wherein said transmitting step comprises creating patterns on a monitor to transmit a computer system identity information.

3. The method of claim 2, wherein the computer system identity information is a serial number of the computer system.

4. A system comprising:

a detector which detects tampering of a computer system; and

a video device capable of emitting electromagnetic field signals in response to a detecting of tampering as detected by the detector.

5. The system of claim 4, wherein the detector comprises a tamper bit which is set when tampering is detected.

6. The system of claim 4, wherein the video device is a monitor capable of creating a pattern to transmit a computer system identity information.

7. The system of claim 4, wherein the video device is a video card capable of creating a pattern to transmit a computer system identity information.

8. The system of claim 4, wherein the computer system identity information is a serial number of the computer system.

9. The system of claim 4, further comprising:

a receiver capable of receiving the electromagnetic field signals; and

a means for investigating the tampering.

10. A method comprising the steps of:

(a) detecting tampering of a computer system; and

(b) creating patterns on a monitor to transmit a computer system identity information.

11. The method of claim 10, wherein the computer system identity information is a serial number of the computer system.

12. The method of claim 10, further comprising:

(c) receiving the patterns; and

(d) investigating the tampering.

13. A system comprising:

a detector circuit which detects evidence of tampering of a computer system; and

a monitor which creates patterns to transmit a computer system identity information.

14. The system of claim 13, wherein the detector circuit comprises a tamper bit which is set when tampering is detected.

15. The system of claim 13, wherein the computer system identity information is a serial number of the computer system.

16. The system of claim 13, further comprising:

a receiver capable of receiving the patterns; and

an investigating circuit which investigates the tampering.

17. A method comprising the steps of:

(a) detecting tampering of a computer system;

(b) creating patterns on a monitor to transmit a serial number of the computer system;

(c) receiving the patterns; and

(d) investigating the tampering.

18. A comprising the steps of:

(a) detecting tampering of a computer system;

(b) creating patterns on a video card to transmit a serial number of the computer system;

(c) receiving the patterns; and

(d) investigating the tampering.

19. A system comprising:

a means for detecting tampering of a computer system, comprising, a tamper bit which is set when tampering is detected;

a monitor capable of creating patterns to transmit a serial number of the computer system;

a receiver capable of receiving the patterns; and

a means for investigating the tampering.

20. A system comprising:

a means for detecting tampering of a computer system, comprising, a tamper bit which is set when tampering is detected;

a video card capable of creating patterns to transmit a serial number of the computer system;

a receiver capable of receiving the patterns; and

a means for investigating the tampering.

21. A system comprising:

a tamper detector which detects a tampering in a first system and generates a tamper signal in response to the tampering;

a monitor which provides visible and invisible display output; and

an alarm subsystem, coupled to said tamper detector and said monitor, comprising a processor for processing digital data and memory for storing digital data and coupled to the processor and a control program stored in the memory and accessible by the processor to direct the processing of digital data by the processor, the control program and the processor cooperating, when the control program is executing on the processor and in response to the tamper signal, in generating invisible display output on said monitor which encodes information indicative of the first system;

whereby the information indicative of the first system is radiated by the parasitic electromagnetic fields of said monitor.

22. The system of claim 21, further comprising:

a second system comprising;

a parasitic electromagnetic field receiver which receives the parasitic electromagnetic fields emitted by said monitor as encoded by said security subsystem by said generated invisible display output and generates a received output signal; and

a decoder which decodes the received output signal and generates information indicative of the first system.

23. A system comprising:

a tamper detector which detects a tampering in a first system and generates a tamper signal in response to the tampering;

a monitor which provides visible and invisible display output; and

an security subsystem, coupled to said tamper detector and said monitor, comprising a processor for processing digital data and memory for storing digital data and coupled to the processor and a control program stored in the memory and accessible by the processor to direct the processing of digital data by the processor, the control program and the processor cooperating, when the control program is executing on the processor and in response to the tamper signal, in;

(a) determining if a priority access password (PAP) system is engaged;

(b) disabling the first system when said determination (a) is made;

(c) generating invisible display output on said monitor which encodes information indicative of the first system when said determination (a) is not made, whereby the information indicative of the first system is radiated by the parasitic electromagnetic fields of said monitor.

24. The system of claim 23, further comprising:

a second system comprising;

a parasitic electromagnetic field receiver which receives the parasitic electromagnetic fields emitted by said monitor as encoded by said security subsystem by said generated invisible display output and generates a received output signal; and

a decoder which decodes the received output signal and generates information indicative of the first system.