Selective file erasure using metadata modifications and apparatus

• US 8,782,089 B2
• Filed: 08/22/2013
• Issued: 07/15/2014
• Est. Priority Date: 12/22/2005
• Status: Expired due to Fees

• Current Assignee: Alan Joshua Shapiro
• Original Assignee: Alan Joshua Shapiro
• Inventors: Shapiro, Alan Joshua
• Primary Examiner(s): Woo, Isaac M
• Application Number:
  US13/973,453
• Publication Number:
  US 20130339408A1
• Time in Patent Office: 327 Days
• Field of Search: 707600-899
• US Class Current: 707/791
• CPC Class Codes: G06F 16/00 Information retrieval; Database structures therefor; File system structures therefor
• CPC Class Codes: G06F 16/13 File access structures, e.g. distributed indices arrangements of input from, or output to, record carriers G06F3/06
• CPC Class Codes: G06F 16/162 Delete operations erasing in storage systems G06F3/0652
• CPC Class Codes: G06F 16/164 File meta data generation
• CPC Class Codes: G06F 8/61 Installation
• CPC Class Codes: G06F 8/62 Uninstallation
• CPC Class Codes: G06F 8/63 Image based installation; Cloning; Build to order
• CPC Class Codes: G06Q 20/123 Shopping for digital content
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99956 File allocation

Abstract

A process that ensures the virtual destruction of data files a user wishes to erase from a storage medium, such as a hard drive, flash drive, or removable disk. This approach is appropriate for managing custom distributions from a large file sets as it is roughly linear in compute complexity to the number of files erased but is capped when many files are batch erased.

Claims

1. A computer-implemented method for modifying a first storage medium having a plurality of files stored therein, wherein the plurality of files are stored on the first storage medium according to a file system, the method comprising:

rendering at least a portion of the plurality of files unavailable for use through data structures on the first storage medium maintained by the file system unless and until a modification operation is performed;

obtaining a first set of metadata describing each file of the plurality of files, wherein the first set of metadata includes directory information that identifies locations on the first storage medium at which the plurality of files are stored; and

automatically modifying a first subset of the first set of metadata such that the modified directory information metadata corresponds to a first subset of the unavailable files and such that each file contained within the first subset of the unavailable files is made available for use.

2. The method of claim 1, further comprising overwriting a first data block of at least a first file of the unavailable files not contained within the first subset, and overwriting one or more data blocks of the at least first file that are subsequent to the first data block.

3. The method of claim 1, further comprising encrypting at least a portion of the plurality of files.

4. The method of claim 1, wherein the obtaining of the first set of metadata describing each file of the plurality of files includes obtaining the first set of metadata from the first storage medium.

5. The method of claim 1, wherein the obtaining of the first set of metadata includes obtaining the first set of metadata from a location not on the first storage medium, and wherein the automatically modifying of the first subset of the first set of metadata includes writing the modified directory information metadata into storage locations used by an operating system for access to the first subset of the unavailable files.

6. The method of claim 1, further comprising:

after the automatically modifying of the first subset of the first set of metadata, operatively coupling the first storage medium to an end-user information-processing device for a first time.

7. The method of claim 1, further comprising automatically modifying the first storage medium such that, in place of at least a first file of the unavailable files not contained within the first subset, data space becomes available for storage of other files.

8. The method of claim 1, wherein the automatically modifying of the first subset of the first set of metadata includes:

constructing a list containing the first subset of the unavailable files and storing the list in a hash table;

scanning the first set of metadata; and

copying, based on the list stored in the hash table, the first subset of the first set of metadata into a second set of metadata.

9. A non-transitory computer-readable medium having instructions stored thereon for causing a suitably programmed computer to execute a method for modifying a first storage medium having a plurality of files stored therein, wherein the plurality of files are stored on the first storage medium according to a file system, the method comprising:

rendering at least a portion of the plurality of files unavailable for use through data structures on the first storage medium maintained by the file system unless and until a modification operation is performed;

obtaining a first set of metadata describing each file of the plurality of files, wherein the first set of metadata includes directory information that identifies locations on the first storage medium at which the plurality of files are stored; and

automatically modifying a first subset of the first set of metadata such that the modified directory information metadata corresponds to a first subset of the unavailable files and such that each file contained within the first subset of the unavailable files is made available for use.

10. The computer-readable medium of claim 9, further comprising instructions such that the method further comprises overwriting a first data block of at least a first file of the unavailable files not contained within the first subset, and overwriting one or more data blocks of the at least first file that are subsequent to the first data block.

11. The computer-readable medium of claim 9, further comprising instructions such that the method further comprises encrypting at least a portion of the plurality of files.

12. The computer-readable medium of claim 9, further comprising instructions such that the obtaining of the first set of metadata describing each file of the plurality of files includes obtaining the first set of metadata from the first storage medium.

13. The computer-readable medium of claim 9, further comprising instructions such that the obtaining of the first set of metadata includes obtaining the first set of metadata from a location not on the first storage medium, and such that the automatically modifying of the first subset of the first set of metadata includes writing the modified directory information metadata into storage locations used by an operating system for access to the first subset of the unavailable files.

14. The computer-readable medium of claim 9, further comprising instructions such that the method further comprises, after the automatically modifying of the first subset of the first set of metadata, operatively coupling the first storage medium to an end-user information-processing device for a first time.

15. The computer-readable medium of claim 9, further comprising instructions such that the method further comprises automatically modifying the first storage medium such that, in place of at least a first file of the unavailable files not contained within the first subset, data space becomes available for storage of other files.

16. The computer-readable medium of claim 9, further comprising instructions such that the automatically modifying of the first subset of the first set of metadata includes:

constructing a list containing the first subset of the unavailable files and storing the list in a hash table;

scanning the first set of metadata; and

copying, based on the list stored in the hash table, the first subset of the first set of metadata into a second set of metadata.

17. An apparatus comprising:

a processor;

a first storage medium that has a plurality of files stored therein, wherein the plurality of files are stored on the first storage medium according to a file system;

a protection module that executes in the processor and that is operatively coupled to the first storage medium, wherein the protection module is operable to render at least a portion of the plurality of files unavailable for use through data structures on the first storage medium maintained by the file system unless and until a modification operation is performed;

a first set of metadata that describes each file of the plurality of files, wherein the first set of metadata includes directory information that identifies locations on the first storage medium at which the plurality of files are stored; and

a grypher that executes in the processor and that is operatively coupled to the first storage medium, wherein the grypher is operable to automatically modify a first subset of the first set of metadata such that the modified directory information metadata corresponds to a first subset of the unavailable files and such that each file contained within the first subset of the unavailable files is made available for use.

18. The apparatus of claim 17, wherein the grypher is further configured to overwrite a first data block of at least a first file of the unavailable files not contained within the first subset, and to overwrite one or more data blocks of the at least first file that are subsequent to the first data block.

19. The apparatus of claim 17, wherein the first set of metadata is located on the first storage medium.

20. The apparatus of claim 17, further comprising an end-user information-processing device, wherein the first storage medium is operatively coupled to the end-user information-processing device for a first time after the grypher automatically modifies the first subset of the first set of metadata.