CN101206656A - File safety deletion system and method - Google Patents

File safety deletion system and method Download PDF

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Publication number
CN101206656A
CN101206656A CNA2006101708003A CN200610170800A CN101206656A CN 101206656 A CN101206656 A CN 101206656A CN A2006101708003 A CNA2006101708003 A CN A2006101708003A CN 200610170800 A CN200610170800 A CN 200610170800A CN 101206656 A CN101206656 A CN 101206656A
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file
block
deletion
bitmap
document
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CN101206656B (en
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张玥
陈玄同
刘文涵
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XUZHOU LIFANG ELECTROMECHANICAL EQUIPMENT MANUFACTURING CO., LTD.
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Inventec Corp
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Abstract

The invention discloses a system of safely deleting files and a method thereof. Firstly, a requested action is taken according to a file request sent by an operating system; secondly, the type of the file request is judged whether to be a file deleting request; when the file request is the file deleting request, a file system bitmap structure before the deletion operation corresponding to the file deleting request and a file system bitmap structure after the deletion operation are compared to obtain the file corresponding to the deletion operation; finally, the data block content of the deletion file is cleared according to the deletion file.

Description

File safety deletion system and method
Technical field
The present invention relates to a kind of file deleting system and method, relate in particular to the system and method for classified papers in a kind of safety deletion computing machine.
Background technology
Usually some have in the environment of confidentiality in government offices, enterprise etc., have comprised a large amount of classified papers or sensitive data in the computing machine, and are therefore very important for the management of these files and data.Yet move on computers or when deleting these data, operating system can not be clean with data dump usually, just left out the provider location index of preserving data, this just will leak to confidential information and stay opportunity.At present some recover softwares and utilize above-mentioned leak then can obtain these confidential datas, and then cause tremendous loss for corresponding enterprise or unit even country.
Described a kind of method of thorough deleted file data in the United States Patent (USP) 6070174, but it only is confined to New Technology File System (NTFS, New Technology File System), and is not suitable for other file system or operating system, for example Linux etc.Therefore, the enforcement of prior art is subjected to the restriction of OS Type and file system type.
Summary of the invention
In order to solve above-mentioned the problems of the prior art and defective, the object of the present invention is to provide a kind of be applicable to various operating systems and file system and can be safely, the file deleting system and the method for deleted file up hill and dale.
File safety deletion system provided by the present invention comprises a file system driving module, a judge module, a bitmap (bitmap) construction module, a comparing module and a removing module; In this, file system driving module is carried out a solicit operation in order to the file request of sending according to operating system, and backspace file request, judge module receives file request to judge this request type, the bitmap structure module is in order to setting up the block of file system bitmap with expression file place, and according to the renewal of solicit operation recorded bit graph structure; When comparing module was file deletion requests when the file request type, the bitmap structure that upgrades after bitmap structure in the comparison bitmap structure module before the deletion action and the deletion action was to search the deletion action corresponding file; And removing module is removed the block content at deleted file place in order to according to the deleted file of searching.
According to file safety deletion system of the present invention, wherein reference position, length and the data content district of the bitmap structure include file system bitmap of file system, here length is represented the block quantity at file place, and the data content district represents the state of the block at file place with binary bit sequence.And, each binary digit of data content district of the bitmap structure that upgrades after bitmap structure before the comparing module comparison deletion action and the deletion action, and then the block at acquisition deletion action corresponding file place.Removing module then obtains the reference position of deleted file place block and length with the block zero clearing.
In addition, the present invention also provides a kind of file safety deletion method, comprises following steps: set up a file system bitmap according to file place block; Carry out a solicit operation and updating file system bitmap according to the file request that operating system is sent; Whether the type of judging file request is file deletion requests; When request was file deletion requests, the block bitmap structure of the file system of upgrading after the block bitmap structure of the file system before the corresponding deletion action of comparison file deletion requests and the deletion action was to obtain the deletion action corresponding file; And the block content of removing its place according to deleted file.
According to file safety deletion method of the present invention, wherein reference position, length and the data content district of file system bitmap structure include file system bitmap, length is represented the block quantity at file place, and the data content district represents the block state at file place with binary bit sequence.Therefore, when file request is file deletion requests, can change the data content district of its place block correspondence according to deleted file, with updating file system bits graph structure.
File safety deletion system of the present invention and method judge by the request type that detecting operating system passes to file system driver whether a deletion action takes place, and after deletion action is finished, the block that does not re-use is found in variation by file system bitmap before and after the comparison deletion, and then these block contents of zero clearing are to reach the purpose of thorough deletion confidential data.The present invention is not only applicable to the file delete operation of high level of security in various operating systems and the file system, and under the prerequisite of the artificial participation that does not need the user, deletes related data safely, up hill and dale, therefore can not cause the leakage of confidential data.In addition, deletion action is finished on the operating system backstage, thereby can avoid influencing any operation of user.
Describe the present invention below in conjunction with the drawings and specific embodiments, but not as a limitation of the invention.
Description of drawings
Fig. 1 is the system block diagrams of file safety deletion system of the present invention;
Fig. 2 is the general steps process flow diagram of file safety deletion method of the present invention;
Fig. 3 is the process flow diagram of the file system bitmap comparison step of file safety deletion method of the present invention; And
Fig. 4 is the process flow diagram that the block of file safety deletion method of the present invention is removed step.
Wherein, Reference numeral
12 operating systems
14 judge modules
16 file system driving module
18 comparing module
20 bitmap structure modules
22 removing modules
Step 202 operating system is sent file request to file system driver
Step 204 is called file system driver and is carried out solicit operation
Step 206 is returned this operation requests
Does step 208 judge that request type is a deletion action?
Step 210 is obtained the message bit pattern of carrying out before the delete file operation with afterwards
Step 212 compares above-mentioned old bitmap structure and new bitmap structure
Step 214 finds out deleted file place block according to comparative result
Step 216 is removed the content of deleted file place block
The result is to operating system for step 218 return
Step 302 reads the file system bitmap and the old file system bitmap of renewal
In the step 304 pair file system bitmap compare in each binary sequence position
Is the block of step 306 sequence bit correspondence changed into and is not used?
Step 308 is removed content in the corresponding data block
Does step 310 arrive the bitmap afterbody?
Step 312 is preserved this updating file system bitmap
Step 402 obtains the reference position and the length of deleted file place block
Step 404 is with the block zero clearing
Step 406 with data sync to disk
Embodiment
About feature of the present invention and enforcement, conjunction with figs. is described in detail as follows as most preferred embodiment now.
Please refer to Fig. 1, this figure is the system block diagrams of file deleting system of the present invention.
As shown in Figure 1, file deleting system of the present invention comprises judge module 14, comparing module 18, file system driving module 16, bitmap structure module 20 and removing module 22.Describe principle of work of the present invention in detail below in conjunction with Fig. 1.
Judge module 14 capturing operation systems 12 mail to file system driving module 16, the file operation requests of file system driver for example, and then transmit this and ask to file system driving module 16.Respective operations is carried out in the request that file system driving module 16 is sent according to operating system.For example request is when the deleted file, and 16 of file system driving module are carried out deletion action, and the user mode of corresponding change deleted file place block be " use ", and is no longer occupied to represent these block; Perhaps, ask to be data read.Then, file system driving module 16 return requests are to judge module 14.
Judge module 14 is judged its type according to the request that receives, and when judging that request type is delete file operation, then calls comparing module 18.The bitmap structure that comparing module 18 is upgraded after in order to the bitmap structure of relatively carrying out block in the deletion action preceding document system and deletion action, and then search the deletion action corresponding file.The block bitmap structure of file system once at first is described here, and bitmap structure module 20 is set up the diagrammatic representation of the block at file place in the current file system in order to data-driven block position, quantity and user mode with bitmap form.The file system bitmap structure comprises the bitmap reference position, bitmap lengths and data content district, the wherein integer representation of bitmap reference position; Bitmap lengths also is an integer, in order to the quantity of the block that writes down in the log file system bitmap; The data content district represents with binary sequence, the state of a data block of each sign in this binary sequence, and for example 0 expression block is unoccupied, and 1 expression block is occupied, and the length in data content district is determined by bitmap lengths.
File system driving module 16 can be made corresponding change with the binary digit of the block of file delete correspondence in the bitmap after carrying out removal request, for example change 0 into by 1, and expression corresponding data block is no longer occupied, and promptly file wherein is deleted.Comparing by turn of data content district carried out in 18 front and back according to bitmap structure of comparing module, the binary digit that changes, and then find out the file and the place block thereof of deletion.Therefore, comparing module 18 is called removing module 22, and then the content of removing module 22 block that will not re-use according to the bitmap comparative result is thoroughly removed.At last, judge module 14 is back to operating system 12 with operating result, therefore finishes the deletion action of file.
Please refer to Fig. 2 now, this figure is the general steps process flow diagram of file safety deletion method of the present invention.As shown in the figure, file safety deletion method of the present invention comprises following steps: at first operating system is sent file request (step 202) to file system driver, and for example the deletion action of a certain file is carried out in request.Carry out corresponding requests operation (step 204), return request (step 206) then according to above-mentioned request call file system driver.Whether then the operation requests type is judged, be deletion action (step 208) to confirm.If not deletion action then finishes; Otherwise, obtain file delete operation file system bitmap structure and deletion action bitmap structure afterwards before.
Here need set up a file system bitmap structure according to block position, quantity and user mode in the file system, and then the diagrammatic representation of setting up the block at file place with bitmap form.The file system bitmap structure comprises the bitmap reference position, bitmap lengths and data content district, the wherein integer representation of bitmap reference position; Bitmap lengths also is an integer, in order to the quantity of the block that writes down in the log file system bitmap; The data content district represents with binary sequence, the state of a data block of each sign in this binary sequence, and for example 0 expression block is unoccupied, and 1 expression block is occupied, and the length in data content district is determined by bitmap lengths.Therefore, can change the data content district of its place block according to the deleted file of deletion action correspondence, corresponding binary digit in the graphic sequence of ascending the throne is with according to deletion action updating file system bits graph structure.
Then, compare (step 212) according to new, the old bitmap structure before and after the deletion action, and find out the block (step 214) at deleted file place according to comparative structure.Then, remove content (step 216) in the block of searching, last return result is to operating system (step 218).
About the bitmap of step 212 is more specific can be with reference to figure 3, this figure is the process flow diagram of the file system bitmap comparison step of file safety deletion method of the present invention.As shown in the figure, at the file system bitmap that reads the renewal of representing the deletion action correspondence respectively and old file system bitmap (step 302) afterwards, each binary sequence position in the file system bitmap is compared (step 304) by turn.Then, the data content district value of representing according to current binary bit sequence, judge whether the corresponding data block changes into the state (step 306) of not using, for example binary digit for example changes into 0 by 1, expression corresponding data block is unoccupied, and promptly file wherein is deleted, and this is then to advance to step 308, remove content in the corresponding data block, with thorough deletion data wherein.If the block of corresponding sequence bit is still being used, judge then then whether the comparison operation reaches the afterbody (step 310) of bitmap, if do not reach the bitmap afterbody, then advances to step 304, continue to carry out the comparison operation until arriving the bitmap afterbody.Preserve the file system bitmap (step 312) of final updating at last, use when next time relatively treating.
In addition, remove step about the block of file safety deletion method of the present invention and please refer to Fig. 4.As shown in the figure, at first obtain the block reference position and the length (step 402) at deletion action respective file place, then with corresponding data block zero clearing (step 404), to data sync (step 406) to disk wherein at last, so far promptly finish the thorough removing of file content in the block.
Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection domain of the appended claim of the present invention.

Claims (10)

1. a file safety deletion system is characterized in that, includes:
One file system driving module is carried out a solicit operation in order to the file request of sending according to operating system, and returns this document request;
One judge module receives this document request, to judge this document request type;
One bitmap structure module, in order to setting up the block of file system bitmap with expression file place, and according to the renewal of this solicit operation record this document system bitmap;
One comparing module when this document request type is file deletion requests, is compared this document system bits graph structure that upgrades after this document system bits graph structure before the deletion action in this bitmap structure module and the deletion action, to search this deletion action corresponding file; And
One removing module in order to according to this deleted file of searching, is removed the block content at this deleted file place.
2. file safety deletion system according to claim 1, it is characterized in that, this document system bits graph structure comprises reference position, length and the data content district of this document system bitmap, this length is represented the block quantity at file place, and this data content district represents the state of the block at file place with binary bit sequence.
3. file safety deletion system according to claim 2, it is characterized in that, each binary digit of data content district of this document system bits graph structure that upgrades after this document system bits graph structure before this comparing module comparison deletion action and the deletion action, and then obtain the block at this deletion action corresponding file place.
4. file safety deletion system according to claim 2 is characterized in that, this removing module obtains the reference position of this deleted file place block and length with this block zero clearing.
5. file safety deletion system according to claim 3 is characterized in that, this document system drive module changes corresponding data content regions in this document system bitmap according to this deleted file place block.
6. a file safety deletion method is characterized in that, comprises following steps:
Set up a file system bitmap according to file place block;
Carry out a solicit operation and upgrade this document system bitmap according to the file request that operating system is sent;
Judge whether this document request type is file deletion requests;
When this request was file deletion requests, this document system bits graph structure that upgrades after this document system bits graph structure before the corresponding deletion action of comparison this document removal request and the deletion action was to obtain this deletion action corresponding file; And
Remove the block content at its place according to this deleted file.
7. file safety deletion method according to claim 6, it is characterized in that, this document system bits graph structure comprises reference position, length and the data content district of this document system bitmap, this length is represented the block quantity at file place, and this data content district represents the block state at file place with binary bit sequence.
8. file safety deletion method according to claim 7, it is characterized in that, when this document request is file deletion requests, also comprise the step that changes its corresponding data content regions according to this deleted file place block, to upgrade this document system bits graph structure.
9. file safety deletion method according to claim 8 is characterized in that, the step of this comparison file system bitmap structure also comprises following steps:
Read this updating file system bits graph structure;
Compare the binary bit sequence of this updating file system bits graph structure and the preoperative this document system bits of file delete graph structure by turn; And
Find out the block at this deleted file place according to this comparison result.
10. file safety deletion method according to claim 7 is characterized in that, the step of the block at this deleted file place of this zero clearing also comprises following steps:
Obtain the reference position and the length of this block;
This block of zero clearing; And
In data sync to a disk in this block.
CN200610170800A 2006-12-22 2006-12-22 File safety deletion system and method Expired - Fee Related CN101206656B (en)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101409946A (en) * 2008-11-28 2009-04-15 飞图科技（北京）有限公司 Method capable of thoroughly deleting data of mobile phone memory card
CN101795320A (en) * 2010-01-28 2010-08-04 惠州Tcl移动通信有限公司 Method for cleaning up files in mobile communication terminal
CN101901261A (en) * 2010-07-23 2010-12-01 南京国电南自轨道交通工程有限公司 Method for storing real-time database by using similar cluster
CN102332014A (en) * 2011-09-14 2012-01-25 奇智软件（北京）有限公司 Method and device for deleting file
CN103164656A (en) * 2012-06-01 2013-06-19 北京安天电子设备有限公司 Method and system for erasing hidden file based on visible file
CN103186482A (en) * 2011-12-28 2013-07-03 联想(北京)有限公司 Method and device for deleting data in hard disc
CN104615504A (en) * 2015-02-06 2015-05-13 浪潮(北京)电子信息产业有限公司 Method and device for achieving data protection
CN105843807A (en) * 2015-01-12 2016-08-10 中国移动通信集团公司 Data deleting method, device and platform

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CN103853850B (en) * 2014-03-28 2017-02-15 北京工业大学 Method and system for eliminating data for user-centered Android system

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US6081800A (en) * 1997-02-28 2000-06-27 Oracle Corporation Creating bitmaps from multi-level identifiers
US5991778A (en) * 1997-09-30 1999-11-23 Stratfor Systems, Inc. Method and apparatus for real-time secure file deletion
CN1331063C (en) * 2003-06-10 2007-08-08 联想(北京)有限公司 On-line data backup method based on data volume snapshot
CN100349139C (en) * 2004-02-19 2007-11-14 华为技术有限公司 Method for writing data on source film in pistolgraph process

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101409946A (en) * 2008-11-28 2009-04-15 飞图科技（北京）有限公司 Method capable of thoroughly deleting data of mobile phone memory card
CN101795320A (en) * 2010-01-28 2010-08-04 惠州Tcl移动通信有限公司 Method for cleaning up files in mobile communication terminal
CN101901261A (en) * 2010-07-23 2010-12-01 南京国电南自轨道交通工程有限公司 Method for storing real-time database by using similar cluster
CN102332014A (en) * 2011-09-14 2012-01-25 奇智软件（北京）有限公司 Method and device for deleting file
CN103186482A (en) * 2011-12-28 2013-07-03 联想(北京)有限公司 Method and device for deleting data in hard disc
CN103164656A (en) * 2012-06-01 2013-06-19 北京安天电子设备有限公司 Method and system for erasing hidden file based on visible file
CN103164656B (en) * 2012-06-01 2015-12-16 北京安天电子设备有限公司 Based on the method and system of visible mutation erasing hidden file
CN105843807A (en) * 2015-01-12 2016-08-10 中国移动通信集团公司 Data deleting method, device and platform
CN105843807B (en) * 2015-01-12 2019-07-05 中国移动通信集团公司 A kind of data-erasure method, equipment and platform
CN104615504A (en) * 2015-02-06 2015-05-13 浪潮(北京)电子信息产业有限公司 Method and device for achieving data protection
CN104615504B (en) * 2015-02-06 2017-11-10 浪潮(北京)电子信息产业有限公司 A kind of method and device for realizing data protection

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Effective date of registration: 20191220

Address after: No. 99, University Road, high tech Zone, Xuzhou City, Jiangsu Province

Patentee after: XUZHOU LIFANG ELECTROMECHANICAL EQUIPMENT MANUFACTURING CO., LTD.

Address before: Taipei City, Taiwan, China

Patentee before: Yingda Co., Ltd.

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Granted publication date: 20100519

Termination date: 20191222