Method and apparatus for providing system security to personal computer ...

United States Patent m

Shipman et al.

[54] METHOD AND APPARATUS FOR

PROVIDING SYSTEM SECURITY TO
PERSONAL COMPUTER SYSTEMS USING
TRANSPARENT SYSTEM INTERRUPT

[75] Inventors: Mark Shipman, Hillsboro; Orville
Christeson. Portland, both of Oreg.

[73] Assignee: Intel Corporation, Santa Clara, Calif.

[21] Appl. No.: 535,725
[22] Filed: Sep. 28, 1!><>5

[51] Int CI.6 G06F 3/02; G06F 13/00;

H04L 9/32; G06K 5/00

[52] U.S. CI 340/825.31; 340/825.34;

380/4; 380/25; 395/200.06; 235/382; 235/382.5

[58] Field of Search 340/825.31.825.34.

340/34; 380/23. 25. 4; 235/380. 382. 382.5; 395/734. 735. 742. 186, 200.06. 187.01;

364/188. 189

[56] References Cited

U.S. PATENT DOCUMENTS

4,942,606 7/1990 Kaiser etal 380/4

5,097,506 3/1992 Kaiser, Jr. et al 380/25

5,173,490 12/1992 Lantz et al 380/25

5,187,352 2/1993 Blair etal 235/382

5^63,157 11/1993 Janis 395/600

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US005724027A

[ii] Patent Number: 5,724,027 [45] Date of Patent: Mar. 3, 1998

5,313,639 5/1994 Chao 395/725

5,339,437 8/1994 Yeun 395/700

5,355,414 10/1994 Hale et al 380/25

5,377,269 12/1994 Heptig et al 380/25

5,408,536 4/1995 Lemelson 382/2

5,465,084 11/1995 Cottrell 340/825.31

5,577,209 11/1996 Boyle et al 395/200.06

Primary Examiner—Brian Zimmerman

Assistant Examiner—Yonel Beaulieu

Attorney, Agent, or Firm—Blakely. Sokoloff. Taylor &

Zafman

[57] ABSTRACT

A transparent system management interrupt (SMI) handler equipped with system security functions is provided to a personal computer (PC) for providing system security to the PC. Additionally, the keyboard controlling facility of the PC is enhanced to cooperate with the SMI handler to deliver system security under the direction of the SMI handler. The SMI handler's system security functions include a number of functions for handling a number of security related events detected by the keyboard controlling facility. The keyboard controlling facility is enhanced to operate in one of three modes, a normal mode, a sleuth mode, and a secured mode, under which the keyboard controlling facility allows "unrestricted" keyboard operations, communicates exclusively with the SMI handler, and allows only "restricted" keyboard operations respectively.

25 Claims, 17 Drawing Sheets