US006622248B1
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`a2, United States Patent
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`(10) Patent No.:
`US 6,622,248 B1
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` Hirai (45) Date of Patent: Sep. 16, 2003
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`(54) FILE DATA RETRIEVING DEVICE AND
`RECORDING MEDIUM CONTAINING
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`COMPUTER PROGRAM FOR
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`CONTROLLING THE SAME
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`IP
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`6-149153
`9-44521
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`5/1994
`2/1997
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`* cited by examiner
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`(75)
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`Primary Examiner—Thomas R. Peeso
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`(74) Attorney, Agent, or Firm—Edwards & Angell, LLP;
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`David G. Conlin; George W. Hartnell, III
`ABSTRACT
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`Inventor: Tokuyuki Hirai, Nara (JP)
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`(73) Assignee: Sharp Kabushiki Kaisha, Osaka (JP)
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`(*) Notice:
`Subject to any disclaimer, the term ofthis
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`patent is extended or adjusted under 35
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`US.C. 154(b) by 0 days.
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`A file data retrieving device includes: an input section for
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`(21) Appl. No.: 09/339,760
`inputting a search character string and various instructions;
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`a storage section that previously stores a plurality of
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`Filed:
`Jun. 24, 1999
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`encoded file data; a decoding section for decoding the
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`Foreign Application Priority Data
`encoded file data by use of a cryptograph key prepared in
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`advance; an extracting section for extracting,
`from the
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`Jun. 25, 1998
`(IP) woe eee ceeeccesseecseecnsseneeeene 10-178948
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`decoded file data, a file name and a plurality of key words
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`(SL) Unt. C0 eee ecccccccsecseeseeseeseereeseeseeneesees GO06F 1/24
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`related to the file data; an encoding section for encoding the
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`(52) U.S. Ch. eens 713/193; 713/200; 713/201
`extracted key words; a storage processing section for allow-
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`(58) Field of Search oo... eee 713/193, 200,
`ing the storage section to store the encoded key words as
`713/201
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`access keysofthefile data in correspondence with the stored
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`file data; andaretrieving section for allowing the encoding
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`References Cited
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`section to encode the search character string which is input
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`U.S. PATENT DOCUMENTS
`by the input section for retrieving the file name of the
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`encodedfile data, searching for an access key that coincides
`4,118,788 A * 10/1978 Roberts oo...ee 707/3
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`with the encoded search character string, and retrieving the
`5,704,060 A * 12/1997 Del Monte ...
`- 707/104.1
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`file name that correspondsto the access key. Also a record-
`5,710,719 A *
`1/1998 Houle wc. eee 382/232
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`ing medium contains a computer program for controlling the
`5,713,009 A *
`1/1998 DeRosa et al. ...... 713/2
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`file data retrieving device.
`FOREIGN PATENT DOCUMENTS
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`5-101102
`4/1993
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`(22)
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`(30)
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`JP
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`4 Claims, 5 Drawing Sheets
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`COMMUNI-
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`DISPLAY
`STORAGE
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`CATING
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`SECTION
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`STORAGE
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`PROCESSING
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`EXTRACTING
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`RECORDING
`MEDIUM
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`8
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`SECTION
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`CONTROLLING SECTION (COMPUTER) |
` USER KEY
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`ENCODING
`DECODING
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`SECTION
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`(DECODING/ENCODING DVICE)
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`RETRIEVING
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`SETTING
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`12
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`JUDGING
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`Page 1 of 12
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`Netskope Exhibit 1008
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`Page 1 of 12
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`Netskope Exhibit 1008
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`U.S. Patent
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`Sep. 16, 2003
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`Sheet 1 of 5
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`US 6,622,248 BI
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`ONIGHUOOSY
`ONILOVHLXSA
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`ONIGOOSA
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`Page 2 of 12
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`Netskope Exhibit 1008
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`Page 2 of 12
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`Netskope Exhibit 1008
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`U.S. Patent
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`Sep. 16, 2003
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`Sheet 2 of 5
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`US 6,622,248 B1
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`FIG. 2
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`FILE AREA
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`(ENCODED)
`FILE 2 (ENCODED)
`FILE 1
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`'Searchdata 1-1:||!Searchdata 2-2;
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`: Searchdata 2-1
`: Searchdata 4-2
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`i Searchdata 6-2:
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`PLAINTEXT KEY WORD
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`RETRIEVAL OBJECT 1-1
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`INDEX AREA
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`Netskope Exhibit 1008
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`Page 3 of 12
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`Netskope Exhibit 1008
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`U.S. Patent
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`Sep. 16, 2003
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`Sheet 3 of 5
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`US 6,622,248 B1
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`FIG. 3
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`|| ACCESS KEY REGISTRATION PROCESS |
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`S300
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`DECODE FILE DATA|$301
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`EXTRACT A PLURALITY
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`OF KEY WORDS
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`ENCODE THE KEY
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`WORDS
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`FILE NAME
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`REGISTER THE
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`TOGETHER WITH THE
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`INPUT RETRIEVAL
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`ENCODE THE RETRIEVAL|o919
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`RETRIEVE A FILE NAME BY
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`SEARCHING FOR AN ACCESS|_93943
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`KEY THAT COINCIDES WITH
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`CHARACTER STRING
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`Page 4 of 12
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`Netskope Exhibit 1008
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`Page 4 of 12
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`Netskope Exhibit 1008
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`U.S. Patent
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`Sep. 16, 2003
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`Sheet 4 of 5
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`US 6,622,248 B1
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`FIG. 4
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`FILE AREA
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`FILE 3 (ENCODED)
`(ENCODED) FILE2 (ENCODED)
`FILE 1
`‘Searchdata 2-2'||!Searchdata3-3}
`i Searchdata 4-3:
`i Searchdata 4-2:
`: Searchdata 5-3:
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`i: Searchdata 3-1 ;
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`‘Searchdata 5-1:||iSearchdata 5-2:
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`PLAINTEXT KEY WORD |CIPHERTEXT KEY WORD |USER KEY
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`RETRIEVAL OBJECT 1-1
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`RETRIEVAL OBJECT 5-1, Searchdata 5-1,5-3|USER A
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`Page 5 of 12
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`Netskope Exhibit 1008
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`Netskope Exhibit 1008
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`U.S. Patent
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`Sep. 16, 2003
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`Sheet 5 of 5
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`US 6,622,248 B1
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`FIG. 5
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`|| ACCESS KEY REGISTRATION PROCESS|| S500
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`SEND FILE DATA TO|coq
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`JUDGING SECTION
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`S502
`iS THE FILE DATA
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`ENCODED?
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`DECODE THE FILE
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`ENCODE THE
`IS THE FILE DATA
`EXTRACT A PLURLITY
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`OF KEY WORDS KEY WORDS ENCODED?
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`REGISTER THE
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`WITH THE FILE NAME
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`S511
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`cey9
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`ENCODE THE RETRIEVAL|
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`RETRIEVE A FILE NAME BY
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`THAT COINCIDES WITH THE
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`Netskope Exhibit 1008
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`US 6,622,248 B1
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`1
`FILE DATA RETRIEVING DEVICE AND
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`RECORDING MEDIUM CONTAINING
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`COMPUTER PROGRAM FOR
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`CONTROLLING THE SAME
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`2
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`process and a decoding process. This method eliminates the
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`need to share the same information in secret among the
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`communicating parties by making a cryptograph key pub-
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`licly known and keeping a decoding key retained in secret.
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`This method is referred to as “public key cryptography”
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`because one key is made publicly known.
`CROSS-REFERENCES TO RELATED
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`For example, as a symmetric cryptography method, Japa-
`APPLICATIONS
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`nese Unexamined Patent Publication No. HEI 06(1994)-
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`This application is related to Japanese patent application
`149153 proposes a general-purpose high-speed cryptogra-
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`No. HEI 10-178948 filed on Jun. 25, 1998 whosepriority is
`phy device utilizing a FEAL (fast data encipherment
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`claimed under 35 USC §119,
`the disclosure of which is
`algorithm) in which an enlarged key is created by means of
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`incorporated herein by reference in its entirety.
`an input such as a cryptography key having a 64 bit length
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`and an fk function; the enlarged key is retained; and an input
`BACKGROUND OF THE INVENTION
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`data having a 64 bit
`length, which is a plaintext or a
`1. Field of the Invention
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`ciphertext, and the retained enlarged key are encoded or
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`The present invention relates to a file data retrieving
`decoded by means of an exclusive logical sum and an f
`function.
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`device and a recording medium containing a computer
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`program for controlling the same, and more particularly to
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`On the other hand, as an asymmetric cryptography
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`a file data retrieving device and a recording medium for use
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`method, Japanese Unexamined Patent Publication No. HEI
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`thereof which are applied to a document processing
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`06(1994)-169306 proposes a protocol and a device in which
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`apparatus, such as a word processor or a personal computer,
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`a message part of a public key distribution method is
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`for retrieving a specific file data from a plurality of encoded
`encoded into asymmetric cryptograph keys and the asym-
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`file data stored in a storage device.
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`metric cryptograph keys are exchanged with each other to
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`2. Description of the Related Art
`establish a safe communication amonga plurality ofparties
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`that share a secret key.
`In recent years,
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`processors and personal computers, a large amount of docu-
`Also, a translated document by Yuu Inamura, “Encipher-
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`ment data are utilized at a place of work or at home.
`mentof electronic mails by PGP, S/MIME,Japanese version
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`Large-capacity databases and high speed retrieving
`of DDJ, February 1998 (magazine code 16665-02)-,
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`machines have been studied and developed in order to
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`Author’s preface to the book: “PGP Source Code and
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`rearrange and utilize a large amount of such document data
`Internals”, by Philip Zimmermann ISBN 0-262-24039-4)”
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`effectively.
`discloses a cryptography processing of PGP (Pretty Good
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`that must maintain its
`In the meantime, a document
`Privacy).
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`secrecy is stored in a database in a form encoded by
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`This PGP method uses a symmetric cryptography and an
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`cryptography.
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`asymmetric cryptography in combination, wherebyafter an
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`Asafile retrieval method that does not use cryptography,
`extra key data which differs for each encoding process is
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`there are known,for example, a full text search method and
`created to encode a message body in a symmetric manner,
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`a key word search method.
`the extra key itself is encoded in an asymmetric manner by
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`text search method, Japanese
`For example, as a full
`using a public key of a receiver, and both of the encoded
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`Unexamined Patent Publication No. HEI 05(1993)-101102
`message body and the encoded extra key are sent to the
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`proposes a retrieving device that enables effective retrieval
`receiver. The receiver of the message decodesthe extra key
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`by reducing the volumeofthe file to be used for presearch
`by meansof the receiver’s secret key and then decodes the
`in the full text search on the basis of the full text search
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`extra key by means of the receiver’s secret key and then
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`method by which the required documentdata are drawn out
`decodes the message body by meansof the extra key thus
`decoded.
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`from a secondary storage device that stores a large amount
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`of document data without giving index information for
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`However, the full text search method disclosed in Japa-
`retrieval.
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`nese Unexamined Patent Publication NO. HEI 05(1993)-
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`Onthe other hand, as a key word search method, Japanese
`101102 and the key word search method disclosed in Japa-
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`Unexamined Patent Publication No. HEI 09(1997)-44521
`nese Unexamined Patent Publication No. HEI 09(1997)-
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`proposes an index making device and a documentretrieving
`44521 are directed to plaintexts which are not encoded, and
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`device for specifying a documentbyregistering, as a com-
`it is not possible to directly search for documentdata thatare
`stored in an encoded form.
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`mon identifier (i.e., an index), a word selected from a
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`plurality of different representations in registering the docu-
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`text search
`Therefore,
`in the above-mentioned full
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`ments and comparing an input key word with the index by
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`method, the searching process must be carried out after all
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`the encoded documentdata are decoded. This necessitates an
`utilizing the index in the retrieving process.
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`for
`Further, known cryptography methods include,
`enormous amount of processing in order to make a search
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`example, symmetric cryptography methods and asymmetric
`among the document data existing in a large amount, thus
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`cryptography methods.
`requiring an extra managementin order to safely maintain
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`A symmetric cryptography method is a cryptography
`secrecy of the documentdata.
`60
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`method in which the same key is used for encoding and
`Further, in the above-mentioned key word search method,
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`decoding processes. In this method, a cryptography com-
`it is possible to search for a documentfile if all the document
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`munication is not possible unless the sender and the receiver
`data are decoded to make indices and only the key wordsare
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`share a commonkeydata, so that the problem is how the key
`stored as plaintexts. However, in this method, the key words
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`can be safely shared. This method is referred to as “private
`are read, whereby the secrecy of the document data is
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`key cryptography” because the key must be kept secret.
`destroyed even though the stored document data are
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`An asymmetric cryptography method is a cryptography
`encoded, thus requiring an extra management in order to
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`method in which different keys are used for an encoding
`safely maintain the secrecy of the documentdata.
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`Netskope Exhibit 1008
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`Page 7 of 12
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`Netskope Exhibit 1008
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`

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`3
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`FIG. 3 is a flowchart showing an access key registration
`The techniques disclosed in Japanese Unexamined Patent
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`process and a procedure (1) for a file retrieving process
`Publication No. HEI 06(1994)-149153, Japanese Unexam-
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`ined Patent Publication No. HEI 06(1994)-169306, and the
`according to an embodimentof the present invention;
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`translated document by Yuu Inamura are directed to an
`FIGS. 4(a) to 4(c) are views showing an access registra-
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`encoding process and a decoding process for establishing a
`tion process and an example of contents (2) to be stored in
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`safe communication between parties that share a common
`a storage section and applied to a file retrieving process
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`secret key, and they do not disclose a technique of searching
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`according to an embodiment of the present invention; and
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`for a specific file at a high speed from a plurality of encoded
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`FIG. 5 is a flowchart showing an access key registration
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`file data stored in a storage device.
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`process and a procedure (2) for a file retrieving process
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`SUMMARYOF THE INVENTION
`according to an embodiment of the present invention.
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`DETAILED DESCRIPTION OF THE
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`invention provides a file data retrieving
`The present
`PREFERRED EMBODIMENTS
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`device comprising: an input section for inputting a search
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`character string and various instructions; a storage section
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`A file data retrieving device according to the present
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`that previously stores a plurality of encoded file data; a
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`invention in which a specific file data is retrieved by use of
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`decoding section for decoding the encoded file data by use
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`an encoded key word at a high speed from a plurality of
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`of a cryptograph key prepared in advance; an extracting
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`encodedfile data stored in a storage device while maintain-
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`section for extracting, from the decodedfile data, a file name
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`ing secrecy of the file data may include an input section, a
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`and a plurality of key words related to the file data; an
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`storage section, a decoding section, an extracting section, an
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`encoding section for encoding the extracted key words; a
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`encoding section, a storage processing section andaretriev-
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`storage processing section for allowing the storage section to
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`ing section. An input device as the input section may
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`store the encoded key words as access keys of the file data
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`include,
`for example, a keyboard, a mouse, a pointing
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`in correspondencewith the stored file data; and a retrieving
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`device, or the like. A storage device as the storage section
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`section for allowing the encoding section to encode the
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`may include, for example, a RAM,a floppy disk, a hard disk,
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`search character string which is input by the input section for
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`a writable CD-ROM, an MD, orthelike.
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`retrieving the file name of the encoded file data, searching
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`The decoding section, the extracting section, the encoding
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`for an access key that coincides with the encoded search
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`section, the storage processing section, and the retrieving
`character string, and retrieving the file name that corre-
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`section may be constructed with a computer including a
`spondsto the access key.
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`CPU, a RAM, a ROM, and an I/O port. The ROM may
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`Also, the present invention provides a recording medium
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`include a program that allows each section to perform its
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`containing a computer program for controlling a file data
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`function. The RAM mayfunction as a work buffer.
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`retrieving device,
`the computer program performing the
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`The file data retrieving device according to the present
`functions of: causing a computer operation to input a search
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`invention may further include a user key setting section for
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`character string and various instructions from an input
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`setting a user key by adding to the access key a name of a
`section; causing a computer operation to previously store a
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`user who is permitted to access the access key, wherein,
`plurality of encoded file data in a storage section; causing a
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`upon input ofthe user key by the inputsection,the retrieving
`computer operation to decode the encodedfile data by use of
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`section makes reference to the access keys stored in the
`a cryptograph key prepared in advance; causing a computer
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`storage section, retrieves an access key that corresponds to
`operation to extract, from the decodedfile data, a plurality
`40
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`the user key from the storage section, and allows the
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`of key words andafile namerelated to the file data; causing
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`decoding section to decode a file data corresponding to the
`a computer operation to encode the extracted keywords;
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`file name by meansof the retrieved access key.
`causing a computer operation to store the encoded key
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`words as access keys of the file data in the storage section
`Here, the user key setting section may be constructed with
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`in correspondence with the stored file data; and causing a
`a CPU of a computer and a user key setting program.
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`computer operation to encode the search character string
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`Since this construction makesit possible to set a user key
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`which is input by the input section for retrieving the file
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`by adding to the access key a name of a user who is
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`name of the encoded file data, to search for an access key
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`permitted to access the access key, the user can retrieve the
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`that coincides with the encoded search character string, and
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`encodedfile name byutilizing the user key, and decode the
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`to retrieve the file name that correspondsto the access key.
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`file data corresponding to the retrieved file name.
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`Thus, the present invention providesa file data retrieving
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`The file data retrieving device according to the present
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`device and a recording medium for use thereof in which a
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`invention may further include a judging section for judging
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`whethera file data that has not been encodedis stored in the
`specific file data is retrieved by use of an encoded key word
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`at a high speed from a plurality of encoded file data stored
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`storage section, wherein upon judgmentthatafile data that
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`55
`in a storage device while maintaining secrecyofthefile data.
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`has not been encoded is stored in the storage section, the
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`extracting section is allowed to extract, from the file data
`BRIEF DESCRIPTION OF THE DRAWINGS
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`that has not been encoded,a file name andaplurality of key
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`The present invention will be better understood from the
`wordsrelated to the file data; the storage processing section
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`following detailed description of preferred embodiments of
`is allowed to store the extracted key wordsas access keys of
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`the invention, taken in conjunction with the accompanying
`the file data in the storage section in correspondence with the
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`drawings, in which:
`stored file data; and the retrieving section is allowed to
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`search for an access key that coincides with the search
`FIG. 1 is a block diagram showing a construction of a
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`character string which is input by the input section for
`retrieving device according to the present invention;
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`retrieving the file nameofthe file data and toretrieve thefile
`FIGS. 2(a@) to 2(c) are views showing an access registra-
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`name that corresponds to the access key.
`tion process and an example of contents (1) to be stored in
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`a storage section and applied to a file retrieving process
`Here, the judging section may be constructed with a CPU
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`according to an embodiment of the present invention;
`of a computer and a judging program.
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`US 6,622,248 B1
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`Page 8 of 12
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`Netskope Exhibit 1008
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`Page 8 of 12
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`Netskope Exhibit 1008
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`

`

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`US 6,622,248 B1
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`6
`5
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`A decoding section 7 decodes an encoded file data by
`This construction makesit possible to retrieve a specific
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`using a cryptograph key (public key) which is prepared in
`file at a high speed from a plurality of file data stored in the
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`advance. The decoding section 7 is constructed with a CPU
`storage device irrespective of whether the file data are
`encoded ornot.
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`and a decoding program.
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`An encoding section 8 encodes the key wordsandthefile
`According to another aspect, the present invention pro-
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`name that are extracted. The encoding section 8 is con-
`vides a recording medium containing a computer program
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`structed with a CPU and an encoding program.
`for controlling a file data retrieving device, the computer
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`Here, the decoding section 7 and the encoding section 8
`program performing the functions of: causing a computer
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`are constructed as a decoding/encoding device which stores
`operation to input a search character string and various
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`a cryptograph key data and a decoding/encoding program
`instructions from an input section; causing a computer
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`capable of performing a cryptography process according to
`operation to previously store a plurality of encodedfile data
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`the symmetric encoding method, the asymmetric encoding
`in a storage section; causing a computer operation to decode
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`method, or the PGP method.
`the encoded file data by use of a cryptograph key prepared
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`in advance; causing a computer operation to extract, from
`A storage processing section 9 allows the storage section
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`the decoded file data, a plurality of key words andafile
`5 to store the encoded key words and the encodedfile name
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`namerelated to the file data; causing a computer operation
`as access keys in the index area. The storage processing
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`to encode the extracted key words; causing a computer
`section 9 is constructed with a CPU anda storage processing
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`program.
`operation to store the encoded key wordsas access keys of
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`the file data in the storage section in correspondence with the
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`A retrieving section 10 allows the encoding section 8 to
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`stored file data; and causing a computer operation to encode
`encode a search character string (key word) input from the
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`the search character string which is input by the input section
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`input section 2, searches for an access key that coincides
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`for retrieving the file name of the encodedfile data, to search
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`with the encoded search character string, and retrieves the
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`for an access key that coincides with the encoded search
`file name that correspondsto the access key. The retrieving
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`character string, and to retrieve the file name that corre-
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`section 10 is constructed with a.CPU andaretrieving
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`spondsto the access key.
`program.
`In the retrieving device according to this
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`By using this recording medium, a file data retrieving
`embodiment,
`the key word search method is adopted.
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`device of the present invention is realized in which an
`However, the retrieval of ordinary documents may beper-
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`intended file is picked up from a plurality of encoded file
`formed by the full text search method.
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`data stored in the storage section, and the file data is
`Auser key setting section 11 sets a user key by adding to
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`retrieved at a high speed.
`the access key a name of a user who is permitted to access
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`the access key. The user Key setting section 11 is constructed
`EMBODIMENTS
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`with an input key, a CPU, and a user key setting program.
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`A judging section 12 judges whether a file data that has
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`not been encoded is stored in the storage section 5. The
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`judging section 12 is constructed with a CPU and a judging
`program.
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`A recording medium 13 stores a program for controlling
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`the file data retrieving device of the present invention. The
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`recording medium is constructed with an IC card made of an
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`EEPROM, a floppy disk, a hard disk, a writable CD-ROM,
`or an MD.
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`The file data retrieving device of the present invention can
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`be easily realized by installing the controlling program of
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`the present invention stored in the recording medium 13,
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`into a RAM ofthe controlling section 1 or into a RAM of a
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`For example, the recording medium 13 may contain a
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`computer program for allowing the controlling section 1
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`(computer) to input a search character string and various
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`instructions from the input section 2; to previously store a
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`plurality of encoded file data in the storage section 5;
`to
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`decode the encoded file data by use of a cryptograph key
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`prepared in advance; to extract, from the decodedfile data,
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`a plurality of key words and a file namerelated to the file
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`data; to encodethe extracted key words;to store the encoded
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`key words as access keysin the storage section 5; to encode
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`the search character string input by the input section 2; to
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`search for an access key that coincides with the encoded
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`search character string; and to retrieve the file name that
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`correspondsto the access key.
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`In this embodim