KR20200051243A - Method for Controlling File Access and Recording Medium Storing Computer Program thereof - Google Patents

Abstract

The present invention relates to a file access setting apparatus and a method thereof and, in particular, to a file access setting method for controlling access to a file by converting a specific field of an access target file. According to the present invention, the file access setting method includes the steps of: obtaining an access target file; decompressing the access target file based on the obtained compression type of the access target file; extracting header data describing data attributes of the access target file from the decompressed access target file; converting at least one field in the extracted header data; and storing header data including the at least one converted field in the access target file.

Description

File access control method and computer program stored in a recording medium {Method for Controlling File Access and Recording Medium Storing Computer Program thereof}

The present invention relates to an apparatus and method for controlling file access. More specifically, the present invention relates to a file access setting apparatus and method for maintaining security of a file processed in a Hangul word processor.

2. Description of the Related Art Recently, as computer-based working environments have become more common, security incidents in which personal information or confidential information contained in electronic documents related to electronic documents are leaked differently from the intention of the document creator have increased. In Korea, the word processing of "Hangul" is becoming more common, and the occurrence of security incidents related to documents used in "Hangul" is increasing. As the incidence of document security incidents increases, the need for document security is gradually increasing, and in Korea, Digital Right Management (DRM) is leading the document security market. Recently, in addition to DRM, solutions such as a data loss prevention (DLP) method and a document centralization method have been provided.

In the modern society in which e-commerce is active, the cost of storing and distributing various documents or documents continues to increase, and in particular, there is a limit that requires more costs than storing or distributing documents in order to solve security problems for electronic documents.

For the management of electronic documents containing only confidential information of individuals or companies, it is often used with encryption and decryption techniques, and various algorithms such as disk encryption or file encryption are also used. For example, disk encryption is a technology that encrypts an entire disk or a partial file with a password, and refers to a technology that encrypts a storage device such as an HDD, SSD, or USB memory, or encrypts a file system. There are some aspects that are not suitable for recent trends such as exchange of documents through. In addition, the encryption / decryption technology for digital documents has a limitation in that performance is reduced on a document processing system or a system cost is required.

Accordingly, there is a need for a document security technique that effectively controls access to electronic files and is advantageous in terms of cost and performance.

Korean Open Patent No. 10-2010-0043140 A

The present invention has been devised to solve the above problems, and discloses an apparatus and method for setting file access. In particular, based on the structure of a file, there is disclosed a file access setting apparatus and method for setting or releasing access to a file by modifying a specific field in the file.

The present invention was devised to achieve the above object, and the file access setting apparatus of the present invention includes a file acquiring unit for acquiring a file to be accessed; A decompression unit for decompressing the access target file based on the obtained compression type of the access target file; A header data extracting unit extracting header data describing data attributes of the access target file from the decompressed access target file; A field converting unit converting at least one field in the extracted header data; And a storage unit for storing header data including the converted at least one field in the access target file. It includes.

In the present invention, the field conversion unit includes a field detection unit that detects at least one field in the header data using preset field location information; And a field value changing unit changing a field value stored in the detected at least one field. In addition, the at least one field may be converted by storing the changed field value in the at least one field according to the field location information.

The access target file includes a compression flag indicating the compression status of the access target file in the header data, and the decompression unit compresses the access target file based on the compression status of the target file indicated by the compression flag. Can be unlocked.

In addition, in order to achieve the above object, the file access releasing apparatus of the present invention includes a file acquiring unit for acquiring an access target file whose access is blocked; A decompression unit for decompressing the access target file based on the obtained compression type of the access target file; A header data extracting unit extracting header data describing data attributes of the access target file from the decompressed access target file; A field recovery unit for recovering at least one field in the extracted header data; And a storage unit for storing header data including the recovered at least one field in the access target file. It includes.

In the present invention, the field recovery unit includes a field detection unit that detects at least one field in the header data using preset field location information; And a field value reduction unit for reducing the field value stored in the detected at least one field. Further comprising, the at least one field may be recovered by storing the reduced field value in the at least one field according to the field location information.

In addition, in order to achieve the above object, the file access setting method of the present invention comprises: obtaining a file to be accessed; Decompressing the access target file based on the obtained compression type of the access target file; Extracting header data describing data attributes of the access target file from the decompressed access target file; Converting at least one field in the extracted header data; And storing header data including the converted at least one field in the access target file. It includes.

In the present invention, the access target file includes a compression flag indicating the compression status of the access target file in the header data, and the decompressing step includes the access target based on the compression status of the target file indicated by the compression flag. You can extract the files.

In the present invention, the converting may include detecting at least one field in the header data using preset field location information; And changing a field value stored in the detected at least one field. In addition, the at least one field may be converted by storing the changed field value in the at least one field according to the field location information.

In addition, in order to achieve the above object, the file access release method of the present invention comprises the steps of obtaining an access target file whose access is blocked; Decompressing the access target file based on the obtained compression type of the access target file; Extracting header data describing data attributes of the access target file from the decompressed access target file; Recovering at least one field in the extracted header data; And storing header data including the recovered at least one field in the access target file. It includes.

In the present invention, the recovering may include detecting at least one field in the header data using preset field location information; And reducing the field value stored in the detected at least one field. Further comprising, the at least one field may be recovered by storing the reduced field value in the at least one field according to the field location information.

The present invention also discloses a computer program stored in a computer-readable recording medium for executing the above-described file access setting method on a computer.

According to the present invention, access to a file can be controlled based on the structure of the file.

In particular, it is possible to effectively maintain the security of the file by using the transform field in the target file.

1 is a block diagram of a file access setting apparatus according to an embodiment of the present invention.
2 is an enlarged block diagram of a field conversion unit in the embodiment of FIG. 1.
3 is a block diagram of an apparatus for releasing file access according to an embodiment of the present invention.
4 is an enlarged block diagram of a field recovery unit in the embodiment of FIG. 3.
5 is a flowchart of a file access setting method according to another embodiment of the present invention.
FIG. 6 is an enlarged flowchart of the step of transforming a field in the embodiment of FIG. 5.
7 is a flowchart of a file access release method according to an embodiment.
8 is an enlarged flow diagram of a step of recovering a field in the embodiment of FIG. 7.
9 is a flowchart of a file access setting method according to another embodiment of the present invention.
10 is a diagram for describing a file structure of an access target file, header data, and compression flag according to an embodiment.
11 is a flowchart of a file access release method according to another embodiment of the present invention.
12 is a view for explaining the structure of a file access control device corresponding to a file access setting device and a file access release device according to another embodiment of the present invention.
13 is a view for explaining a file access control system including a file access setting device and a file access release device according to an embodiment.
14 is a diagram for describing an operation of controlling access to a Korean document using a file access control system according to an embodiment.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the description with reference to the accompanying drawings, the same or corresponding components are assigned the same drawing numbers, and redundant description thereof will be omitted.

In addition, in describing the present invention, when it is determined that detailed descriptions of related well-known configurations or functions may obscure the subject matter of the present invention, detailed descriptions thereof may be omitted.

Terms used in the present application are only used to describe specific embodiments, and are not intended to limit the terms. Singular expressions include plural expressions unless the context clearly indicates otherwise. Each of the steps described below may be provided with one or several software modules or may be implemented with hardware in charge of each function, or a combination of software and hardware.

The specific meaning and examples of each term will be described below in the order of each drawing.

Hereinafter, a configuration of a file access setting apparatus according to an embodiment of the present invention will be described in detail with reference to the related drawings.

1 is a block diagram of a file access setting apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the file access setting apparatus 10 according to an embodiment includes a file acquiring unit 120, a decompressing unit 140, a header data extracting unit 160, a field converting unit 180, and storage It may include a portion 190. According to another embodiment, the file access setting apparatus 10 may further include a rating determination unit (not shown) and a correction unit (not shown). However, not all of the illustrated components are required components, and the file access setting apparatus 10 may be implemented by more components than the illustrated components, and the file access setting apparatus 10 may be implemented by fewer components. Can be implemented.

According to one embodiment, the file access setting device 10 includes the converted field by acquiring the access target file, extracting header data from the obtained access target file, and converting at least one field in the extracted header data It is possible to restrict access to the access target file provided with the header data.

The target access file described in this specification may include an electronic document file processed on a computer, and the target access file described in this specification is a document file processed in a word processor, such as Korean or Microsoft Word (MS). word processor software. Hereinafter, a case in which the target access file is processed by the Hangul word processor software will be described as an example.

According to an embodiment, the file acquiring unit 120 acquires a file to be accessed. For example, the file acquiring unit 120 may acquire a Korean document file as an access target file for setting a user access authority. The Hangul document file acquired by the file acquiring unit 120 may be a Hangul document file identified by the default extension hwp. The basic extension (Basis File Extension) for identifying the type of the file to be accessed described in this specification may include doc, docx, hwp, txt, xls, xlsx, ppt, pptx, pdf, psd. The case where is hwp will be described as an example.

The Hangul document, which is an access target file according to the present disclosure, is compressed by a compression format defined by the second extension. For example, the second extension may include zlib, zip, apk, rar, tar, 7z, etc., but hereinafter, the second extension will be described based on a compression format defined by zlib using a compress or deflate function. For example, the file to be accessed herein is an electronic document compressed in a compressed format defined by zlib, and the file access setting device 10 is configured to decompress the file to be accessed based on the compressed format defined by zlib. The structure of the target access file can be analyzed.

The decompression unit 140 decompresses the access target file based on the compression format of the access target file. That is, the decompression unit 140 may decompress the access target file compressed in a compression format according to the second extension. The file to be accessed according to the present disclosure may further include media data including video data or image data in addition to text data, and the decompressing unit 140 accesses the data to different extents according to attributes of data included in the file to be accessed. The target file can be decompressed. For example, the decompression unit 140 may maintain compression of media data included in the access target file and decompress only text data.

Also, the decompression unit 140 may maintain different compression rates of at least some fields of the access target file according to attributes of data included in the access target file. As described later, the decompression unit 140 may decompress the access target file based on the compression state of the access target file indicated by the compression flag in the header data.

The header data extracting unit 160 according to an embodiment extracts header data describing data attributes of the access target file from the access target file based on a compression format defined by zlib. For example, the header data extraction unit 160 may directly extract header data from an access target file whose extension is changed to a second extension (eg, compressed in a compressed format defined by the second extension). However, the header data extracting unit 160 may extract header data from the access target file decompressed by the decompressing unit.

The header data according to the present disclosure is a file describing data attributes of an access target file, and may preferably include information regarding a compressed state of data included in the access target file and information regarding a file version of the access target file.

The rating determining unit (not shown) according to an embodiment may determine the security level of the access target file based on the content attribute of the access target file. For example, the rating determining unit may determine the security level of the access target file based on at least one of attributes of text data and media data included in the access target file. According to another embodiment, the rating determining unit accesses based on at least one of a connection relationship of each block and sub-blocks in the file to be accessed, location information of blocks, sub-blocks, and fields, and the number of times the text stored in the file to be accessed is viewed. The security level of the target file can be determined. The field converter 180 according to the present disclosure may convert at least one field in header data differently according to the determined security level. This will be described with reference to FIG. 2.

The field conversion unit 180 according to an embodiment includes a field detection unit 182 and a field value changing unit 184. According to another embodiment, the field conversion unit 180 may further include a correction unit (not shown). However, not all of the illustrated components are required components, and the field converting unit 180 may be implemented by more components than the illustrated components, or the field converting unit 180 may be implemented by fewer components. Can be.

For example, the field converter 180 may convert at least one field in the extracted header data. The header data according to the present disclosure may include information about a file signature, information about a file version, information about a file attribute, and a standby array, and the field converting unit 180 includes information about a file signature and a file version At least one field of a field in which information, file attribute information is stored, and a standby array may be converted. The field converting unit 180 detects at least one field in the header data using preset field position information that identifies the positions of a plurality of fields in the header data, changes the field value stored in the detected at least one field, , At least one field in the header data may be converted by storing the changed field value in at least one field in the header data.

According to an embodiment of the present disclosure, if the file to be accessed is a document processed by a Hangul word processor identified by the extension hwp, the field converting unit 180 is in a field corresponding to a position separated by 36 bytes from the header data start position. You can change the field value. For example, the field converting unit 180 sets the reference field in the header data or adjacent to the header data as the starting position of the header data, and sets the reference field as the starting position, and specifies the reference field in the header data separated by a predetermined data distance. The field can be identified.

The field location information according to the present disclosure may refer to coordinate information of a field spaced apart by a predetermined distance based on the location where the header data starts in the access target file. The header data according to the present disclosure may further include a compression flag indicating the compression status of the file to be accessed, and the field converter 180 may include at least one of the header data based on the compression status of the target file indicated by the compression flag. You can convert fields.

According to an embodiment, the field converter 180 may convert a field in header data extracted from the access target file while maintaining the compressed state of the access target file. For example, the access target file of the present disclosure may further include a compression flag indicating the compression state of the access target file, and the field converter 180 maintains the compression state of the access target file indicated by the compression flag while maintaining the header. You can convert fields of data. That is, the file access setting apparatus 10 can reduce the access control cost for the file because the field in the header data can be converted using the compression flag while maintaining the compressed state of the file to be accessed. That is, the field converter 180 may convert at least one field in the header data based on the compression state of the access target file indicated by the compression flag.

According to another embodiment of the present disclosure, the field converter 180 may convert fields in header data in different ways based on the determined security level. For example, when the field converting unit 180 according to the present disclosure converts fields in header data in different ways based on the determined security level, the position and detection of the field to be detected in the header data according to the determined security level The number of to-do fields and the target field value to be stored in the to-be-detected field are set differently, and at least one field in the header data is changed using differently set position of the to-be-detected field, the number of the to-be-detected field and the target field value May be

The correction unit (not shown) according to an embodiment may correct the length and offset of the converted header data when the length of the header data including at least one field in which the changed field value is stored is changed. For example, when the field converter 180 changes the field value stored in the header data by using a target field value that does not match the length of the field value stored in the header data, the length of the header data may vary. have. Accordingly, when the length of the header data is changed, a relative position of fields in the header data is changed, and as a result, a problem may arise that the access restriction setting for the access target file is not made accurately.

That is, when the length of the header data according to the present disclosure is changed, the correction unit adjusts the length of the header data, or resets the positional information of a plurality of fields in the target file based on the reference field to correct the offset of the header data. The access setting device 10 can accurately set access to a file to be accessed. The correction unit according to the present disclosure may be included in the field conversion unit 180, but is included in the file access setting device 10 other than the field conversion unit 180, and the header data including at least one field in which the changed field value is stored. It is possible to detect whether the length is changed, and if the length of the header data is changed, the length and offset of the converted header data may be corrected.

The storage unit 190 according to an embodiment may store header data including at least one converted field in the access target file. The file access setting apparatus 10 according to the present disclosure stores the changed field value in at least one field according to the preset field location information, and finally stores the changed header value in the access target file, thereby saving the header data. You can convert my field.

According to another embodiment, the storage unit 190 may further store conversion identification information indicating whether at least one field in the header data has been converted, and information on the time at least one field has been converted, in an access target file.

The storage unit 190 according to the present disclosure may include an internal memory or an external memory. The internal memory includes, for example, volatile memory (eg, dynamic RAM (DRAM), static RAM (SRAM), or synchronous dynamic RAM (SDRAM)), non-volatile memory (eg, OTPROM (one time programmable ROM (PROM), programmable ROM (PROM), erasable and programmable ROM (EPROM), electrically erasable and programmable ROM (EEPROM), mask ROM, flash ROM, flash memory (e.g. NAND flash or NOR flash, etc.), hard drives, Or it may include at least one of a solid state drive (SSD).

In addition, the external memory according to the present disclosure is a flash drive (flash drive), compact flash (CF), secure digital (SD), micro-SD (micro secure digital), mini-SD (mini secure digital), xD (extreme digital) ), MMC (multi-media card) or memory stick (memory stick). The external memory may be functionally and / or physically connected to the file access setting device 10 through various interfaces. Programs stored in the storage unit 190 may be classified into a plurality of modules according to their functions. For example, a file acquisition unit, a decompression unit, a header data extraction unit, a field conversion unit, a storage unit, and an access control module It may be classified as, but is not limited to this.

2 is an enlarged block diagram of a field conversion unit in the embodiment of FIG. 1.

According to an embodiment, the field conversion unit 180 includes a field detection unit 182 and a field value changing unit 184. For example, the field detection unit 182 may detect at least one field in header data using preset field location information. For example, the header data may include a reference field, a file signature, a file version, a field storing information about a file attribute, and a waiting field, which are classified according to the field location information, and the field detection unit 182 may set a predetermined field location. At least one field may be detected according to the information.

According to an embodiment, the field value changing unit 184 may change a field value stored in at least one detected field. For example, the fields in the header data may include a preset field value (eg, binary data), and the field value changing unit 184 is a target determined based on at least one of a compression state and a determined security level indicated by the compression flag. The field value may be used to change a field value previously stored in fields in the header data.

3 is a block diagram of a file access release device 20 according to an embodiment of the present invention.

The file access release device 20 according to an embodiment may include a file acquisition unit 320, a decompression unit 340, a header data extraction unit 360, a field recovery unit 380, and a storage unit 390. Can be. According to another embodiment, the file access release device 20 may further include an identification unit (not shown) and a correction unit (not shown). However, not all of the illustrated components are required components, and the file access releasing apparatus 20 may be implemented by more components than the illustrated components, and the file access releasing apparatus 20 may be implemented by fewer components. Can be implemented.

The file acquiring unit 320 according to an embodiment acquires an access target file whose access is blocked. Since the file acquiring unit 320 may correspond to the configuration of the file acquiring unit 120 of FIG. 1, a detailed description will be omitted. The decompression unit 340 according to an embodiment may decompress the access target file based on the obtained compression type of the access target file. Since the decompression unit 340 may correspond to the configuration of the decompression unit 140 of FIG. 1, a detailed description will be omitted.

The header data extracting unit 360 according to an embodiment extracts header data indicating data attributes of the access target file from the access target file based on a compression format (eg, zlib) of the access target file. Since the header data extraction unit 360 may correspond to the header data extraction unit 160 of FIG. 1, detailed description will be omitted. This will be described with reference to FIG. 4.

The identification unit according to an embodiment may identify conversion identification information indicating whether at least one field in the header data has been converted. For example, the header data may further include conversion identification information indicating whether at least one field in the header data has been converted (eg, whether a field value in the field has been changed) in the waiting field, and the identification unit is in the waiting field. Based on the conversion identification information, it is possible to identify whether the conversion target field has been converted. According to another embodiment, the identification unit is not included in the field recovery unit 380 but is included in the file access release device 20 to identify whether the conversion target field has been converted.

The field recovery unit 380 according to an embodiment includes a field detection unit 382 and a field value reduction unit 384. The above-described identification unit (not shown) may be further included in the field recovery unit 380. For example, the field recovery unit 380 may recover at least one field in the extracted header data. The header data according to the present disclosure may include a file signature, a file version, a field in which information about a file attribute is stored, and a waiting field, and the field recovery unit 380 stores information about a file signature, file version, file attribute When at least one converted field among the field and the standby field is present, at least one field in the header data may be recovered by reducing the field value in the converted field.

According to another embodiment, the field recovery unit 380 may recover at least one field in the header data based on the conversion identification information stored in the standby field of the header data. For example, if the conversion identification information in the standby field indicates that the converted field in the conversion target field does not exist, the field recovery unit 380 may not recover at least one field in the conversion target field. That is, the file access release device 20 may quickly determine whether to recover the header data by using the conversion identification information of the waiting field in the header data.

The correction unit (not shown) according to an embodiment may correct the length and offset of the converted header data when the length of the header data including at least one field in which the changed field value is stored is changed. Since the correction unit may correspond to the configuration of the correction unit included in the file access setting device 10 of FIG. 1, a detailed description will be omitted. The storage unit 390 according to an embodiment may store header data including the recovered at least one field in the access target file. Since the storage unit 390 may correspond to the storage unit 190 of FIG. 1, detailed description will be omitted.

4 is an enlarged block diagram of a field recovery unit in the embodiment of FIG. 3.

The identification unit according to an embodiment may identify conversion identification information indicating whether at least one field in the header data has been converted. Since the identification part included in the field recovery part may correspond to the identification part in the file access release device of FIG. 3, a detailed description will be omitted.

The field detection unit 382 may detect at least one converted field in the header data using preset field position information or conversion identification information in the header data. For example, when the identified conversion identification information indicates that at least one field converted in the header data exists, the field detector 382 selects at least one converted field in the header data using the preset field position information. Can be detected.

The field value reducing unit 384 according to an embodiment may reduce the field value stored in at least one detected field. For example, initial field values of all fields in the header data may be stored in the standby field in the header data, and the field value reduction unit 384 uses the initial values of the fields pre-stored in the standby field to convert in the header data. Field values of the fields can be reduced. For example, the field value reduction unit 384 may reduce the field value stored in at least one field detected by changing the changed field value in the converted field in the header data to an initial value in the corresponding field. The field value reduction unit 384 may restore the field by storing the recovered field value in at least one field in header data according to the field location information.

5 is a flowchart of a file access setting method according to another embodiment of the present invention.

The file access setting method includes the following steps performed in time series in the file access setting device 10.

In S520, the file acquiring unit acquires the file to be accessed. Since the file acquiring unit may correspond to the configuration of the file acquiring unit 120 of FIG. 1, a detailed description will be omitted.

In S540, the decompression unit decompresses the access target file based on the compression format of the access target file. Since the decompression unit may correspond to the configuration of the decompression unit 140 of FIG. 1, a detailed description will be omitted.

In S560, the header data extracting unit 160 extracts header data describing data attributes of the access target file from the access target file based on a compression format defined by zlib. Since the header data extraction unit may correspond to the configuration of the header data extraction unit 160 of FIG. 1, detailed description will be omitted.

In S580, the field converter may convert at least one field in the extracted header data. For example, the field converting unit may detect at least one field in the header data and change the field value stored in the detected at least one field using preset field position information that identifies the positions of a plurality of fields in the header data. have. Since the field conversion unit may correspond to the configuration of the field conversion unit 180 of FIG. 1, a detailed description will be omitted.

In S590, the storage unit may store header data including the converted at least one field in the access target file. The file access setting apparatus 10 according to the present disclosure stores the changed field value in at least one field according to the preset field location information, and finally stores the changed header value in the access target file, thereby saving the header data. You can convert my field. Since the storage unit may correspond to the configuration of the storage unit 190 of FIG. 1, detailed description will be omitted.

FIG. 6 is an enlarged flowchart of the step of transforming a field in the embodiment of FIG. 5.

In S582, the field detection unit may detect at least one field in header data using preset field location information. Since the field detection unit may correspond to the field detection unit 182 of FIG. 2, detailed description will be omitted.

In S584, the field value changing unit may change the field value stored in the detected at least one field. Since the field value changing unit may correspond to the field value changing unit 184 of FIG. 2, a detailed description will be omitted.

7 is a flowchart of a method for releasing file access according to another embodiment of the present invention.

The file access release method includes the following steps performed in time series in the file access release device 20.

In S720, the file acquiring unit may acquire an access target file whose access is blocked. For example, the file acquisition unit may acquire a Korean document file with access blocked. Since the file acquiring unit may correspond to the file acquiring unit 320 of FIG. 3, detailed description will be omitted.

In S740, the decompression unit decompresses the access target file whose access is blocked. For example, the decompression unit may decompress the Korean document file based on the zlib compression format of the Korean document file. Since the decompression unit may correspond to the configuration of the decompression unit 340 of FIG. 3, a detailed description will be omitted.

In S760, the header data extracting unit extracts header data indicating text attributes of the access target file from the access target file based on the compression format according to the second extension. Since the header data extraction unit may correspond to the header data extraction unit 360 of FIG. 3, a detailed description will be omitted.

In S780, the field recovery unit may recover at least one field in the header data based on the conversion identification information stored in the standby field of the header data. Since the field recovery unit may correspond to the field recovery unit 380 of FIG. 3, detailed description will be omitted.

In S790, the storage unit may store header data including the recovered at least one field in the access target file. Since the storage unit may correspond to the storage unit 390 of FIG. 3, detailed description will be omitted.

8 is an enlarged flow diagram of a step of recovering a field in the embodiment of FIG. 7.

In S782, the field detection unit may detect at least one converted field in the header data using preset field position information or conversion identification information in header data. Since the field detection unit may correspond to the field detection unit 382 of FIG. 4, detailed description will be omitted.

In S784, the field value reducing unit may reduce the field value stored in the detected at least one field. Since the field value reduction unit may correspond to the field value reduction unit 384 of FIG. 4, a detailed description will be omitted.

9 is a flowchart of a file access setting method according to another embodiment of the present invention.

The file access setting method according to another embodiment may include the following steps performed in time series in the file access setting device.

In S910, the file access setting device 10 obtains an access target Hangul file. Although not illustrated in FIG. 9, following S910, the file access setting device 10 may further perform an operation of decompressing the target Hangul file based on the obtained compression type of the target Hangul file.

In S920, the file access setting apparatus 10 may extract header data from the acquired target Hangul file, and change a field value in a field that is 36 bytes away from the start position of the extracted header data.

In S930, the file access setting device 10 may store header data including the changed field value in the target Hangul file.

10 is a diagram for describing a file structure of an access target file, header data, and compression flag according to an embodiment.

Referring to FIG. 10, the access target file 1100 used by the file access setting device 10 or the file access release device 20 includes a reference field 1120, a header block 1140, and a data block 11990 can do. For example, the access target file 1100 may include a plurality of blocks compressed in a zlib compression format. In the present specification, the reference field 1120 is a field for defining field location information of header data, and may not have its own data size, but if necessary (eg, when the length of header data including the converted field is changed) ), The file access setting device 10 may allocate a predetermined data capacity to the reference field.

According to an embodiment, the header block 1140 is a block in which header data is stored, and includes a field and a standby array 1150 in which information about the file signature 1142, the file version 1144, and the file attribute 1146 is stored. It can contain. For example, the header block 1140 is an access target based on information on the file name of the access target file, the file version, whether the access target file is compressed, whether to set access restrictions, whether to save the script, and whether to save the image and video data. Can indicate the data attributes of a file. The data block 1190 includes data about content including text, images, and videos actually stored in the file to be accessed. According to an embodiment, a field at a position spaced apart by 36 bytes using a reference field of header data as a starting position may be a field indicating attribute information of a file to be accessed.

According to an embodiment of the present disclosure, the file signature 1142 is composed of a specific byte in a unique format of the file to be accessed, and may be located at the front of header data. The field where information about the file version 1144 is stored indicates whether the structure of the document format of the file to be accessed has been changed, and whether the version of the current word processor processing the file to be accessed is compatible with the obtained file to be accessed. It can contain. The field in which information about the file attribute 1146 of the access target file is stored may indicate whether the script is stored in the access target file, whether to store image and video data, and information about document history management.

Referring to FIG. 10, the compression flag 1160 according to the present disclosure may be included in the standby array 1150 in the file to be accessed to indicate the compressed state of the file to be accessed. As described above, the decompression unit according to the present disclosure can decompress based on the compression state of the access target file indicated by the compression flag 1160. In addition, as described above, the field converting unit according to the present disclosure may convert at least one field in header data based on the compression state of the target file indicated by the compression flag. The waiting field 1180 is an empty field in which field values in the header data are not stored, and the file access setting device 10 sets a target field value in the waiting field when all field values in other fields in the header data are stored. By storing, at least one field of header data can be converted.

The compression flag 1160 according to the present disclosure includes a reference field 1162, a field in which information 1164 about whether to access the file is compressed, a field in which information about a file length 1166 of header data before compression is stored, and compression A field in which information about the file length of the header data is stored 1168, a field in which information about the file capacity 1170 of the header data before compression is stored, a field in which information about the file capacity 1172 of the header data after compression is stored, and The standby array 1183 field may be included.

For example, the compression status indicated by the compression flag in the header data includes information about whether the file to be accessed is compressed (1164), information about the length of the file before compression (1166), information about the size of the file before compression (1170), It may vary according to at least one of information about a file length after compression 1168 and information about a file capacity after compression 1172.

The file access setting apparatus 10 according to the present disclosure may convert a field of header data in the access target file based on the compression state of the access target file indicated by the compression flag. That is, before converting at least one field in the header data, the file access setting apparatus 10 may first check the compression status of the file to be accessed using a compression flag.

The file access setting apparatus 10 according to the present disclosure may immediately determine the compression state of the access target file by using the information on whether to compress the access target file stored in the compression flag 1160, but before the compression stored in the compression flag The compression state of the file to be accessed may be determined by using at least one of information about the file length of the header data after and information about the capacity of the header data before and after compression.

According to another embodiment, the file access setting apparatus 10 does not read information about the file length of header data before and after compression stored in the compression flag 1160 and information about the capacity of header data before and after compression. In addition, the compression state of the access target file may be determined by summing up information of a block in an access target file, a sub-block included in blocks, and a plurality of fields except for the compression flag.

11 is a flowchart of a file access release method according to another embodiment of the present invention.

The method for releasing file access according to another embodiment may include the following steps performed in time series in the file access releasing device.

In S1110, the file access release device 20 acquires a Korean file with access blocked. Although not illustrated in FIG. 11, subsequent to S1110, the file access release device 20 may further perform an operation of decompressing the target Hangul file based on the obtained compression type of the target Hangul file.

In S1120, the file access release device 20 may extract header data from the obtained target Hangul file, and recover a field value in a field that is 36 bytes away from the start position of the extracted header data. For example, initial field values of all fields in the header data may be stored in the standby field in the header data of the access target Hangul file, and the file access release device 20 uses initial values of the fields previously stored in the standby field. , Field values of changed fields in the header data may be recovered.

In S1130, the file access release device 20 may store header data including the recovered at least one field in a target Hangul file.

12 is a view for explaining the structure of a file access control device corresponding to a file access setting device and a file access release device according to another embodiment of the present invention.

The file access control device 1200 according to the present disclosure may correspond to the file access setting device 10 of FIG. 1 and the file access release device 20 of FIG. 3. For example, the file access setting apparatus 10 according to the present disclosure may include a processor 1300 and a memory 1400. For example, the memory 1400 according to the present disclosure may correspond to the storage 190 of FIG. 1. The processor 1300 according to the present disclosure typically controls the overall operation of the file access setting apparatus 1200 by executing one or more instructions stored in the memory 1400. For example, the processor 1300 executes one or more instructions stored in the memory 1400 to obtain a file acquisition unit 120, a decompression unit 140, a header data extraction unit 160, and a field conversion unit 180. Overall control of the storage unit 190, the identification unit (not shown), the correction unit (not shown), the rating determination unit, the field detection unit 182, and the field value changing unit 184, or the same function as each module You can do

According to another embodiment, the file acquisition unit 120, the decompression unit 140, the header data extraction unit 160, the field conversion unit 180, the storage unit 190, the identification unit (not shown), Bo The functions of the government (not shown), the class determination unit, the field detection unit 182, and the field value changing unit 184 may be performed on a single processor, but may be divided through a plurality of processors. According to another embodiment, the file acquisition unit 120, the decompression unit 140, the header data extraction unit 160, the field conversion unit 180, the storage unit 190, the identification unit (not shown), Bo The government (not shown), the rating determination unit, the field detection unit 182, and the field value changing unit 184 may each include at least one processor, and a file acquisition unit 120 using a processor included in each module ), Decompression unit 140, header data extraction unit 160, field conversion unit 180, storage unit 190, identification unit (not shown), correction unit (not shown), rating determination unit, field detection unit Each function of the 182 and the field value changing unit 184 may be performed.

The file access release device 20 according to the present disclosure may include a processor 1300 and a memory 1400. For example, the memory 1400 according to the present disclosure may correspond to the storage unit 390 of FIG. 3. The processor 1300 according to the present disclosure typically controls the overall operation of the file access release device 1200 by executing one or more instructions stored in the memory 1400. For example, the processor 1300 executes one or more instructions stored in the memory 1400, thereby obtaining a file acquisition unit 320, a decompression unit 340, a header data extraction unit 360, and a field recovery unit 380. Overall control of the storage unit 390, the field detection unit 382, the field value reduction unit 384, the identification unit (not shown), the rating determination unit (not shown), and the correction unit (not shown), or It can perform the same function as the module.

According to another embodiment, the file acquisition unit 320, the decompression unit 340, the header data extraction unit 360, the field recovery unit 380, the storage unit 390, the field detection unit 382, the field value The functions of the reduction unit 384, the identification unit (not shown), the rating determination unit (not shown), and the correction unit (not shown) may be performed in a single processor, but may be dividedly performed through a plurality of processors. According to another embodiment, the file acquisition unit 320, the decompression unit 340, the header data extraction unit 360, the field recovery unit 380, the storage unit 390, the field detection unit 382, the field value The reduction unit 384, the identification unit (not shown), the rating determination unit (not shown), and the correction unit (not shown) may each include at least one processor, and a file using a processor included in each module Acquisition unit 320, decompression unit 340, header data extraction unit 360, field recovery unit 380, storage unit 390, field detection unit 382, field value reduction unit 384, identification unit Each function of the (not shown), the rating determining unit (not shown), and the correction unit (not shown) may be performed.

13 is a view for explaining a file access control system including a file access setting device and a file access release device according to an embodiment.

The file access control system 1500 according to the present disclosure may include a file access setting device 1520 and a file access release device 1560. The file access control system 1500 according to the present disclosure may limit or set a user's access to the contents included in the Hangul document, based on the structure of the Hangul document 1540 which is an object of access control. For example, the file access control system 1500 extracts the header data of the Hangul document and changes the field value of the field corresponding to a distance of 36 bytes from the beginning of the header data (for example, the position of the reference field). A user who does not have permission to access the document 1540 may be blocked.

14 is a view for explaining an operation of controlling access to a Hangul document using a file access control system according to an embodiment.

According to an embodiment, the file access control system 1500 converts at least one field in the header data of the Hangul document, which is an access control object, based on the user input of the user A. Access to a Korean document in which at least one field in the header data is converted may be blocked by the user. The file access control system 1500 may store Hangul files with access blocked in the memory of the file access control system.

According to an embodiment of the present disclosure, the file access control system 1500 recovers at least one modified field in the header data of an access-blocked Hangul document, which is an access control object, based on user B's user input. The Hangul document in which at least one field in the header data is recovered may be allowed access by the user. The file access control system 1500 may store the Hangul file whose access restriction is released in the memory of the file access control system.

The file access control system 1500, the file access setting device 10, and the file access release device 20 according to the present disclosure may be implemented in various types of electronic devices. For example, the file access control system 1500, the file access setting device 10 and the file access release device 20 are for desktops, mobile terminals, laptop computers, tablet PCs, e-book terminals, and digital broadcasting. It may be a terminal, PDA (Personal Digital Assistants), PMP (Portable Multimedia), but is not limited thereto.

All or part of the method of an embodiment of the present invention described above may be embodied in the form of a computer-executable recording medium, such as a program module, being executed by a computer. Here, the computer readable medium can be any available medium that can be accessed by a computer, and includes both volatile and nonvolatile media, removable and non-removable media. In addition, computer readable media may include computer storage media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data.

Further, all or part of a method according to an embodiment of the present invention includes instructions executable by a computer and may be embodied as a computer program (or computer program product) recorded on a medium. The computer program includes programmable machine instructions processed by a processor and may be implemented in a high-level programming language, object-oriented programming language, assembly language, or machine language. . In addition, the computer program may be recorded on a tangible computer-readable recording medium (eg, memory, hard disk, magnetic / optical medium, or solid-state drive (SSD), etc.).

Accordingly, a method according to an embodiment of the present invention may be implemented by executing a computer program as described above by a computing device. The computing device may include at least some of a processor, a memory, a storage device, a high-speed interface connected to the memory and a high-speed expansion port, and a low-speed interface connected to the low-speed bus and the storage device. Each of these components is connected to each other using various buses, and can be mounted on a common motherboard or mounted in other suitable ways.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains may make various modifications, changes, and substitutions without departing from the essential characteristics of the present invention. will be. Therefore, the embodiments and the accompanying drawings disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain the scope of the technical spirit of the present invention. . The scope of protection of the present invention should be interpreted by the claims below, and all technical spirits within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

Claims (17)

In the file access setting method performed by the file access setting device,
Obtaining a file to be accessed;
Decompressing the access target file based on the obtained compression type of the access target file;
Extracting header data representing data attributes of the access target file from the decompressed access target file;
Converting at least one field in the extracted header data; And
Storing header data including the converted at least one field in the access target file; How to set up file access, including. According to claim 1,
The access target file includes a compression flag indicating a compression state of the access target file in the header data,
In the step of releasing, the access target file is decompressed based on the compression state of the target file indicated by the compression flag. The method of claim 1, wherein the converting step
Detecting at least one field in the header data using preset field location information; And
Changing a field value stored in the detected at least one field; Further comprising,
And changing the at least one field by storing the changed field value in the at least one field according to the field location information. The method of claim 3, wherein the field location information
A file access setting method including coordinate information of a field spaced by a predetermined distance based on a position where the header data starts in the access target file. According to claim 2,
The compression flag may include at least one of information on whether the file to be accessed is compressed, information about a file length before compression, information on a file size before compression, information on a file length after compression, and information on a file size after compression. Including,
The compression status of the access target file includes information on whether the access target file is compressed, information on the file length before compression, information on the file size before compression, information on the file length after compression, and information on the file size after compression. File access setting method characterized in that it depends on at least one of the. According to claim 1,
Determining a security level of the file to be accessed; Further comprising,
The converting of the field may include converting at least one field in the header data differently according to the determined security level. The method of claim 1, wherein the storing step
A file for further storing, in the header data, conversion identification information indicating whether at least one field in the access target file including the converted at least one field has been converted, and information on the time when the at least one field has been converted. How to set up access. According to claim 1,
The access target file includes a Hangul document file with an extension of hwp, and the compressed format includes zlib. In the file access release method performed by the file access release device,
Obtaining a file to be accessed which is blocked from accessing;
Decompressing the access target file based on the obtained compression type of the access target file;
Extracting header data describing data attributes of the access target file from the decompressed access target file;
Recovering at least one field in the extracted header data; And
Storing header data including the recovered at least one field in the access target file; How to disable file access, including. The method of claim 9,
The access target file includes a compression flag indicating a compression state of the access target file in the header data,
In the step of releasing, the access target file is decompressed based on the compression state of the target file indicated by the compression flag. The method of claim 10, wherein the recovering step
Detecting at least one field in the header data using preset field location information; And
Reducing field values stored in the detected at least one field; Further comprising,
And recovering the at least one field by storing the reduced field value in the at least one field according to the field location information. A file acquiring unit acquiring a file to be accessed;
A decompression unit for decompressing the access target file based on the obtained compression type of the access target file;
A header data extracting unit extracting header data describing data attributes of the access target file from the decompressed access target file;
A field converting unit converting at least one field in the extracted header data; And
A storage unit for storing header data including the converted at least one field in the access target file; File access setting device comprising a. The method of claim 12,
The access target file includes a compression flag indicating a compression state of the access target file in the header data,
The decompression unit decompresses the access target file based on a compression state of the target file indicated by the compression flag. The method of claim 12, wherein the field conversion unit
A field detector configured to detect at least one field in the header data using preset field location information; And
A field value changing unit for changing a field value stored in the detected at least one field; Further comprising,
And converting the at least one field by storing the changed field value in the at least one field according to the field location information. A file acquiring unit that acquires an access target file whose access is blocked;
A decompression unit for decompressing the access target file based on the obtained compression type of the access target file;
A header data extracting unit extracting header data describing data attributes of the access target file from the decompressed access target file;
A field recovery unit for recovering at least one field in the extracted header data; And
A storage unit for storing header data including the recovered at least one field in the access target file; File access release device comprising a. The method of claim 15, wherein the field recovery unit
A field detector configured to detect at least one field in the header data using preset field location information; And
A field value reduction unit for reducing the field value stored in the detected at least one field; Further comprising,
And recovering the at least one field by storing the reduced field value in the at least one field according to the field location information. A program stored in a computer-readable recording medium that realizes the file access setting method according to any one of claims 1 to 8 through being executed by a processor.

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