Security control for computer power supply subsystem

• US 6,202,161 B1
• Filed: 11/24/1999
• Issued: 03/13/2001
• Est. Priority Date: 05/30/1997
• Status: Expired due to Term

• Current Assignee: Winbond Electronics Corporation
• Original Assignee: Winbond Electronics Corporation
• Inventors: Wang, Cheng-Chih
• Primary Examiner(s): Ray, Gopal C.
• Application Number:
  US09/448,451
• Time in Patent Office: 475 Days
• Field of Search: 713/200-202, 713/300, 713/310, 713/330, 707/9, 708/135, 340/825.31, 340/825.34, 380/3, 380/21, 380/23, 380/25, 380/49
• US Class Current: 713/310
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: G06F 21/81 by operating on the power supply, e.g. enabling or disabling power-on, sleep or resume operations
• CPC Class Codes: G06F 21/83 input devices, e.g. keyboards, mice or controllers thereof
• CPC Class Codes: G06F 3/023 Arrangements for converting discrete items of information into a coded form, e.g. arrangements for interpreting keyboard generated codes as alphanumeric codes, operand codes or instruction codes

Abstract

A computer system power-on security control apparatus is described to provide shielding against unauthorized access to the computer systems. Firmware-level protection is provided instead of the conventional implementation at the operating system level. Repeated power-on and -off cycles inevitable in the process of trial entry of the password of the computer system can be avoided altogether, reducing the risk of potential damages to delicate subsystems in the computer while repeated trial of the password is attempted.

Claims

1. A power-up security control apparatus for a computer system having a mainboard circuitry, a power supply, and a keyboard, the apparatus comprising:

a keyboard input data decoder for receiving and decoding keyboard signals;

a buffer connected to an output of the keyboard input data decoder for storing the decoded keyboard signals in a pre-determined format;

a password memory for storing a password used to power up the computer system;

a comparing unit having inputs connected to the output of the buffer and the password memory, the comparing unit comparing the decoded keyboard signals and the password and generating a matching condition signal indicating whether the decoded keyboard signals and the password match; and

a power supply control unit comprising a logic circuitry and receiving the matching condition signal and subsequently generating a control signal based on a result of a logical operation performed by the logic circuitry on both a matching condition and a status of a main power switch of the computer system, in order to control the power supply of the computer system.

2. The apparatus of claim 1, wherein the power supply complies with the ATX standard, and the power supply control unit comprises a logical NAND circuit performing a NAND operation on the matching condition and the logical status of the main switch of the computer system, and the power supply control unit operates a PS-ON signal to the ATX power supply.

3. The apparatus of claim 1, wherein the password memory is a non-volatile random-access memory device.

4. The apparatus of claim 1, wherein the password memory is a designated memory space in a CMOS configuration memory of the computer system.

5. The apparatus of claim 1, wherein the password memory is a static random-access memory supported by a back-up battery when the computer system is turned off.

6. A system for controlling power-up of a computer system having a keyboard connected to a keyboard controller, said computer system connected to a power source, said system comprising:

a keyboard intercept unit for intercepting keyboard signals directed to the keyboard controller;

a memory for storing a password;

a comparing unit configured to compare received keyboard signals to the stored password; and

a power supply control unit, connected to the comparing unit, outputting a power control signal to turn on the power source for the computer system when keyboard signals match the stored password.

7. The system according to claim 6 further comprising a standby power source configured to output power to the keyboard intercept unit, the comparing unit, and the power supply control unit.

8. The system according to claim 6 further comprising a keyboard input data decoder for receiving and decoding the intercepted keyboard signals.

9. The system according to claim 8, further comprising a buffer connected to an output of the keyboard input data decoder for storing the decoded signals.

10. The system according to claim 9, wherein said comparing unit includes means for comparing the password to the decoded signals stored in the buffer.

11. The system according to claim 6, wherein said power supply control unit includes means for maintaining a power off to the power source when the password does not match the decoded signals.

12. The system according to claim 6, wherein the power supply control unit includes a logical NAND circuit which receives an output of the comparing unit and a logical status of the power source.

13. The system according to claim 6, wherein the keyboard intercept unit includes a pair of buffers configured to receive a pair of signals from the keyboard.

14. The system according to claim 6, wherein the memory is a non-volatile random-access memory.

15. The system according to claim 6, wherein the memory is a designated memory space in a CMOS configuration memory of the computer system.

16. The system according to claim 6, wherein the memory is a static random-access memory supported by a back-up battery when the computer system is turned off.

17. A power-up security control apparatus for a computer system, comprising:

a keyboard input data decoder receiving and decoding keyboard signals and outputting decoded data;

a buffer connected to an output of the keyboard input data decoder for storing the decoded data of the keyboard signals;

a comparing unit having inputs connected to the buffer, the comparing unit comparing the keyboard signals and a predetermined password and generating a signal indicating a result of the comparison; and

a power supply control unit receiving the signal indicating the result of comparison for generating a power-up control signal for a power source of the computer.

18. The apparatus of claim 17, wherein if the result of the comparison between the predetermined password and the keyboard signal is positive, the generated signal is used to turn on power supply control unit and then the power supply control unit brings up an associated computer system.

19. A method for powering up a computer, comprising the steps of:

providing a standby power source, a keyboard, and a password;

receiving a keyboard signal from the keyboard;

processing the keyboard signal;

comparing the processed keyboard signal with the password;

generating a signal indicating a result of the comparison; and

generating a power-up control signal for a power source of the computer if the processed keyboard signal matches the password.

20. The method of claim 19, wherein the standby power source comprises a standby 5-volt power for providing a necessary power for processing and comparing the keyboard signal.

21. The method of claim 19, wherein the password is stored in a password memory.

22. The method of claim 21, wherein the password memory comprises a non-volatile random-access memory device.

23. The method of claim 21, wherein the password memory comprises a designated memory space in a CMOS configuration memory of the computer.