System and method for filtering data received by a computer system

• US 5,996,011 A
• Filed: 03/25/1997
• Issued: 11/30/1999
• Est. Priority Date: 03/25/1997
• Status: Expired due to Term

• Current Assignee: Symantec Corporation (NortonLifeLock Inc.)
• Original Assignee: Unified Research Laboratories Inc.
• Inventors: Humes, Donald Creig
• Primary Examiner(s): Maung, Zarni
• Assistant Examiner(s): WINDER, PATRICE L
• Application Number:
  US08/823,123
• Time in Patent Office: 980 Days
• Field of Search: 395/200.47, 395/200.48, 395/200.49, 395/200.54, 395/200.55, 395/200.59, 395/187.01, 395/188.01, 707/104, 707/9, 709/217, 709/218, 709/219, 709/224, 709/225, 709/229, 709/232, 713/201, 713/202
• US Class Current: 709/225
• CPC Class Codes: G06F 16/9535 Search customisation based on user profiles and personalisation
• CPC Class Codes: H04L 63/0236 Filtering by address, protocol, port number or service, e.g. IP-address or URL
• CPC Class Codes: H04L 63/102 Entity profiles
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

The present invention provides a system and method for restricting access to data received by a computer over a network by filtering certain data from the data received. In a preferred embodiment, the present invention provides a computer based method for filtering objectionable or target text data from World Wide Web pages which are received by a computer system connected to the Internet. According to the method, if the web page requested by the user contains only a minimum of objectionable or target data, the user may receive a portion of the filtered web page for downloading and viewing on his or her computer. If the web page requested contains a large amount of objectionable or target data, the invention will cause a "forbidden" page to be displayed on the user'"'"'s computer monitor.

Claims

1. A computer readable memory containing a computer program for programming a general purpose computer to perform a method for filtering a block of text data containing words received over a network, wherein said method comprises the steps of:

a) providing a listing of target words, each target word in said listing of target words having a respective score associated therewith, which score may be zero, wherein at least one of said target words has a negative score associated therewith;

b) comparing each word in said block of text data to said listing to determine any word in said block of text data which matches one of said target words in said listing so as to determine matched text words and corresponding matched target words; and

c) determining a total score for said block of text data based on said score associated with each matched target word.

2. A computer readable memory as in claim 1, further comprising:

providing a respective replace-variable associated with each of said target words in said listing, each said replace-variable being set to either a true state or a false state; and

replacing each said word in said block of text data that matches one of said target words in said listing having its respective replace-variable set to a true state with a replacement-word to provide a new block of text data.

3. A computer readable memory as in claim 1, further comprising

replacing said block of text data with a substitute block of data if said total score for said block of text data exceeds a predetermined numerical threshold.

4. A computer readable memory as in claim 3, wherein said score associated with each of said target words in said listing comprises a base score and a bonus score, and wherein said negative score associated with said at least one of said target words comprises a negative bonus score and wherein said method further comprises determining said total score for said block of text data based on the respective bonus score associated with at least one of said matched target words.

5. A computer readable memory as in claim 4, wherein said method further comprises determining said total score for said block of text data based on the respective bonus score associated with each of said matched target words having a corresponding matched text word that is positioned within a predetermined proximity of another matched text word in said block of text data.

6. A computer readable memory as in claim 5, wherein said predetermined proximity comprises adjacent words.

7. A computer readable memory as in claim 5, wherein said predetermined proximity comprises a separation of at most one word.

8. A computer based method for filtering a block of text data containing words received over a network, said method comprising the steps of:

a) providing a listing of target words, each target word in said listing of target words having a respective score associated therewith, which score may be zero, wherein at least one of said target words has a negative score associated therewith;

b) comparing each word in said block of text data to said listing to determine any word in said block of text data which matches one of said target words in said listing so as to determine matched text words and corresponding matched target words; and

c) determining a total score for said block of text data based on said score associated with each matched target word.

9. A computer based method as in claim 8, further comprising:

providing a respective replace-variable associated with each of said target words in said listing, each said replace-variable being set to either a true state or a false state; and

replacing each said word in said block of text data that matches one of said target words in said listing having its respective replace-variable set to a true state with a replacement-word, to provide a new block of text data.

10. A computer based method as in claim 8, further comprising

replacing said block of text data with a substitute block of data if said total score for said block of text data exceeds a predetermined numerical threshold.

11. A computer based method as in claim 10, wherein said score associated with each of said target words in said listing comprises a base score and a bonus score and wherein said negative score associated with said at least one of said target words comprises a negative bonus score, and wherein said total score for said block of text data is determined based on the respective bonus score associated with at least one of said matched target words.

12. A computer based method in claim 11, wherein said total score for said block of text data is determined based on the respective bonus score associated with each of said matched target words having a corresponding matched text word that is positioned within a predetermined proximity of another matched text word in said block of text data.

13. A computer based method as in claim 12, wherein said predetermined proximity comprises adjacent words.

14. A computer based method as in claim 12, wherein said predetermined proximity comprises a separation of at most one word.

15. A computer based method as in claim 8, further comprising:

d) providing a respective category-variable associated with each of said target words in said listing for expressing a category with which each of said target words in said listing is associated; and

e) providing an output comprising a record of the respective categories with which each matched target word is associated.

16. A computer based method as in claim 15, further comprising:

determining a total category score for said block of text data based on the respective score and category-variable associated with each matched text word; and

providing said total category score for each category in said output.

17. A computer based method as in claim 16, further comprising:

replacing said block of text data with a substitute block of data if said total category score for a category exceeds a predetermined numerical threshold.

18. A computer based method for filtering a web page received over the World Wide Web and providing an output, said web page having a header portion, a body portion and an associated requested URL, said method comprising the steps of:

a) providing an allow-list of URLs associated with approved web pages;

b) providing a deny-list of URLs associated with disapproved web pages;

c) providing a listing of target words;

d) comparing said requested URL with said URLs in said allow-list, and if said requested URL matches any of said URLs in said allow-list, providing the web page as an output;

e) if said requested URL does not match any of said URLs in said allow-list, comparing said requested URL with said URLs in said deny-list, and, if said requested URL matches any of said URLs in said deny-list, providing an output indicating access to the web page is forbidden;

f) if said requested URL does not match any of said URLs in said deny-list, providing a computer based filter for comparing each word in the header of the web page to said listing to determine any word in the header of the web page which matches one of said target words in said listing; and

g) providing an indication that access to the web page is forbidden or providing a modified version of the web page as an output based upon said determination in step f.

19. A computer based method as in claim 18, further comprising:

h) providing a computer based filter for comparing each word in the body of the web page to said listing to determine any word in the body of the web page which matches one of said target words in said listing; and

i) providing an indication that access to the web page is forbidden or providing a modified version of the web page as an output based upon said determination in step h.

20. A computer system for filtering a block of text data containing words received over a network, comprising:

a general purpose computer; and

a set of instructions for programming said general purpose computer to;

a) provide a listing of target words, each target word in said listing of target words having a respective score associated therewith, which score may be zero, wherein at least one of said target words has a negative score associated therewith;

b) compare each word in said block of text data to said listing to determine any word in said block of text data which matches one of said target words in said listing so as to determine matched text words and corresponding matched target words; and

c) determining a total score for said block of text data based on said score associated with each matched target word.

21. A computer system as in claim 20, wherein said general purpose computer is further programmed in step c to:

provide a respective replace-variable associated with each of said target words in said listing, each said replace-variable being set to either a true state or a false state; and

replace each said word in said block of text data that matches one of said target words in said listing having its respective replace-variable set to a true state with a replacement-word to provide a new block of text data.

22. A computer system as in claim 20, wherein said general purpose computer is further programmed to replace said block of text data with a substitute block of data if said total score for said block of text data exceeds a predetermined numerical threshold.

23. A computer system as in claim 22, wherein said score associated with each of said target words in said listing comprises a base score and a bonus score, and wherein said negative score associated with said at least one of said target words comprises a negative bonus score and wherein said total score for said block of text data is determined based on the respective bonus score associated with each of said matched target words having corresponding matched text word that is positioned within a predetermined proximity of another matched text word.

24. A computer readable memory containing a computer program for programming a general purpose computer to perform a method for filtering a block of text data containing words received over a network, wherein said method comprises the steps of:

a) providing a listing of target words, each target word in said listing of target words having a respective score and bonus score associated therewith, which score and/or bonus score may be zero;

b) comparing each word in said block of text data to said listing to determine words in said block of text data which match one of said target words in said listing so as to determine matched text words and associated matched target words;

c) determining a total score for said block of text data based on;

(i) said score associated with each matched target word and

(ii) said bonus score associated with each matched target word only if said matched target word'"'"'s associated matched text word is within a predetermined proximity to another matched text word in said block of text data.

25. A computer based method for filtering a block of text data containing words received over a network, said method comprising:

a) providing a listing of target words, each target word in said listing of target words having a respective score and bonus score associated therewith, which score and/or bonus score may be zero;

d) comparing each word in said block of text data to said listing to determine words in said block of text data which match one of said target words in said listing so as to determine matched text words and associated matched target words;

e) determining a total score for said block of text data based on;

(i) said score associated with each matched target word and

(ii) said bonus score associated with each matched target word only if said matched target word'"'"'s associated matched text word is within a predetermined proximity to another matched text word in said block of text data.

26. A computer based method for filtering a page of data received over the World Wide Web, wherein said page of data comprises a plurality of blocks of text data, said method comprising:

a) providing a listing of target words, each target word in said listing of target words having a respective score associated therewith, which score may be zero;

b) comparing each word in one of said blocks of text data to said listing to determine words in said first one of said blocks of text data which match one of said target words in said listing so as to determine matched text words and associated matched target words;

c) determining a total score for said one of said blocks of text data based on said score associated with each matched target word;

d) replacing said one of said blocks of text data with a substitute block of data if said total score for said one of said blocks of text data exceeds a predetermined numerical threshold;

e) displaying said one of said blocks of text data or said substitute block of data;

f) repeating steps a through e for each remaining block of text data in said page of data.