EP0449242A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and structure for providing computer security and virus prevention
Assignee: National Semiconductor Corp
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Filing: 1991-03-27
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Granted: —
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Expires: 2011-03-27
Abstract
Abstract Tests are performed prior to or during the boot operation to determine whether files are corrupted. This may indicate the presence of a virus. If a potential error is detected, boot is halted, allowing the user to boot from uncorrupted files. In another embodiment, an uniquely formatted floppy diskette is used as an access diskette serves as a hardware key to gain access. In another embodiment, a host controls information stored locally. In another embodiment, security from unauthorized access is provided once a valid user has legitimately accessed a computer. In response to a predefined hot key or a predetermined period of time during which the user has not provided input, portions of the computer are disabled. Upon entry of access information by the valid user, the disabled features are enabled. In another embodiment, access to the computer is made more difficult in response to invalid access attempts. In one embodiment, once a threshold number of invalid access attempts is reached, the computer is locked up, requiring reboot, thereby increasing the difficulty of a would be intruder to gain access to the computer. In one embodiment, once the threshold value is reached, it is reset to a lower value.
Inventors
- 👤 Bruce William Watson
- 👤 R. Jeff Lee
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 19:04
CPC Classifications
G; G06; G06F; G06F21/00; G06F21/50; G06F21/57; G06F21/575; G06F11/00; G06F11/07; G06F11/08; G06F21/55; G06F21/56; G06F21/562; G06F21/565; G06F11/14; G06F11/1402; G06F11/1415; G06F11/1417
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
80 words
A method for detection of computer viruses or corrupted files, comprising the steps of: initiating a system boot; calculating signature values for one or more files stored in said computer storage; comparing said signature values with previously caluculated and stored signature values for said one or more files; and halting system boot if said step of comparing determines that one or more of said calculated signature values differes from its corresponding one of said previously calculated and stored signature value.
Claim 2
Dependent Claim
25 words
A method as in claim 1 wherein said one or more files comprise files which will be used during the boot operation of said computer.
Claim 3
Dependent Claim
31 words
A method as in claim 2 wherein said one or more files further comprise user specified files which may or may not be used during the boot operation of said computer.
Claim 4
Dependent Claim
19 words
A method as in claim 1 wherein each of said signature values are calculated using more than one method.
Claim 5
Dependent Claim
31 words
A method as in claim 4 wherein each said signature value comprises a plurality of sets of bits, each said set of bits calculated in accordance with an associated signature method.
Claim 6
Dependent Claim
30 words
A method as in claim 1 wherein said previously calculated and stored signatures are stored in a memory area other than computer memory used for normal operation of the computer.
Claim 7
Dependent Claim
28 words
A method as in claim 6 wherein said memory area other than said computer memory can not be accessed by normal operation of said computer after system boot.
Claim 8
Dependent Claim
25 words
A method as in claim 1 wherein said step of initiating a system boot comprises the step of initiating a system boot from secure firmware.
Claim 9
Dependent Claim
114 words
A computer system comprising: mass storage means; boot files, stored in said mass storage means, which are used during a system boot operation; means for storing signature values associated with said boot files; means for generating a system boot signal; means for calculating signature values for said boot files in response to said system boot signal; means for comparing said calculated signature values with corresponding values which have been previously calculated and stored in said means for storing signature values; and means for preventing system boot if one or more of said calculated signature values differs from its corresponding value which has been previously calculated and stored in said means for storing signature values.
Claim 10
Independent Claim
93 words
A method for securing access to a computer system comprising the steps of: preventing access to said computer system until access autorization is verified; receiving an access diskette in a standard diskette drive normally used for data transfer between said computer system and storage diskettes; causing said standard diskette drive to read at least a portion of the contents of said access diskette using a technique different from the technique used by said standard diskette drive to read data from storage diskettes; and allowing access if said access diskette contains valid authorization information.
Claim 11
Independent Claim
48 words
A method for storing security information in a computer network comprising a plurality of computers, comprising the steps of: causing a first one of said computers to transmit data for storage in a second of said computers, said information serving to control user access to said second computer.
Claim 12
Independent Claim
108 words
A method for controlling a computer comprising the steps of: during operation of the computer, detecting the occurrance of either: entry of a selected command from a user; or an elapse of a selected amount of time during which there has been no data or commands inputted by the user; in response to said occurance, performing the following steps: disabling one or more input/output functions of said computer; monitoring for user input of information indicating valid user authorization for use of said computer; and in response to the detection of valid user authorization, enabling said one or more input/output functions of said computer which had previously been disabled.
Claim 13
Dependent Claim
33 words
A method as in claim 12 wherein said one or more input/output functions are selected from the group of functions consisting of keyboard entry, data entry, screen display, printer output, and data transmission.
Claim 14
Dependent Claim
20 words
A method as in claim 12 wherein selected functions of said computer are not disabled in response to said occurance.
Claim 15
Dependent Claim
13 words
A method as in claim 14 wherein said selected functions comprise computer processing.
Claim 16
Dependent Claim
30 words
A method as in claim 14 wherein said selected functions comprise execution of programs currently being run, or in a queue to run, at the time said occurance is detected.
Claim 17
Dependent Claim
26 words
A method as in claim 12 wherein said information indicating valid user authorization comprises a hardware access key, user identification, password information, or a combination thereof.
Claim 18
Independent Claim
62 words
A method for controlling access to a computer comprising the steps of: receiving user authorization information from a prospective user; determining if said user authorization information is valid; if said user authorization information is valid, allowing said prospective user to have access to said computer; and if said user authorization information is invalid, increasing the difficulty of gaining access to said computer.
Claim 19
Dependent Claim
39 words
A method as in claim 18 wherein said step of increasing the difficulty of gaining access to said computer comprises the steps of increasing the amount or intensity of error signals provided in response to invalid user autorization information.
Claim 20
Dependent Claim
48 words
A method as in claim 18 wherein said step of increasing the difficulty of gaining access to said computer comprises the step of requiring said computer to be rebooted in response to a number of invalid user authorization attempts exceeding a threshold number of invalid user autorization attempts.
Claim 21
Dependent Claim
32 words
A method as in claim 20 wherein said threshold number is reduced to a lower threshold number following a number of invalid user authorization attempts which equals or exceeds said threshold number.
References Cited (Backward Citations)
No citation records indexed.
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