Random bit mask generation for obscuring data on nonvolatile memory device

• US 20060015756A1
• Filed: 09/14/2005
• Published: 01/19/2006
• Est. Priority Date: 03/27/2000
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Chrisop, Roy, Van Oosterhout, Jack
• Granted Patent: US 8,010,807 B2
• Time in Patent Office: Days
• US Class Current: 713/193
• CPC Class Codes: G06F 21/608 Secure printing
• CPC Class Codes: G06F 21/62 Protecting access to data via a platform, e.g. using keys or access control rules
• CPC Class Codes: G06F 2221/2143 Clearing memory, e.g. to prevent the data from being stolen
• CPC Class Codes: G06Q 20/382 insuring higher security of transaction

Abstract

A method and apparatus for preventing unauthorized access to information temporarily stored in memory, such as a hard disk drive, associated with a digital document processor, such as a digital copier, printer, or facsimile machine. This invention includes storing information to memory, conducting an operation on the information, and automatically overwriting the information one or more times with a bit mask. Bit masks may be non-random or random sequences of binary values.

Claims

1. A copier comprising:

a nonvolatile data storage having one or more data store locations for storing one or more image data;

means for detecting an end of at least one of the following in the copier;

an image copying operation; and

an image printing operation;

associated with one or more image data stored in the one or more data store locations;

means for generating at least one bit mask; and

means for writing, upon the detection of the end of at least one of the operations, at least a portion of the at least one generated bit mask to the one or more data store locations associated with the one or more stored image data.

2. The copier of claim 1 wherein the means for generating at least one bit mask is a means for generating at least one pseudorandom bit mask.

3. A copier comprising:

a nonvolatile data storage having one or more data store locations for storing one or more image data;

means for detecting at least one of the following in the copier;

an image scanning operation interruption;

an image copying operation interruption; and

an image printing operation interruption;

associated with one or more image data stored in the one or more data store locations;

means for generating at least one bit mask; and

means for writing, upon the detection of at least one of the interruptions, at least a portion of the at least one generated bit mask to the one or more data store locations associated with the one or more stored image data.

4. The copier of claim 3 wherein the means for generating at least one bit mask is a means for generating at least one pseudorandom bit mask.

5. A method of bit masking image data on a nonvolatile data storage associated with a multi-function device, the method comprising the steps of:

testing for at least one of the following in the multi-function device;

an image copying operation;

an image printing operation; and

an image transmitting operation;

associated with one or more image data from at least one memory location on the nonvolatile data storage; and

if an end of at least one of the tested operations is detected;

for two or more bit masking operations;

generating a bit mask; and

writing at least a portion of the generated bit mask to the at least one memory location associated with the one or more image data.

6. The method of claim 5 wherein the step of generating a bit mask is the step of generating a pseudorandom bit mask.

7. The method of claim 5 wherein the image transmitting operation is a facsimile transmitting operation.

8. A method of bit masking image data on a nonvolatile data storage associated with a multi-function device, the method comprising the steps of:

testing for at least one of the following in the multi-function device;

an image copying operation;

an image printing operation; and

an image transmitting operation;

associated with one or more image data from at least one memory location on the nonvolatile data storage; and

if an end of at least one of the tested operations is detected;

generating at least one bit mask; and

for two or more bit masking operations;

writing at least a portion of the at least one generated bit mask to the at least one memory location associated with the one or more image data.

9. The method of claim 8 wherein the step of generating at least one bit mask is the step of generating a pseudorandom bit mask.

10. The method of claim 8 wherein the image transmitting operation is a facsimile transmitting operation.

11. A multi-function device adapted to execute at least one of the following operations—

an image copying operation, an image printing operation, and an image transmitting operation, the device comprising;

a nonvolatile data storage having one or more data store locations for storing one or more image data;

means for detecting at least one of the following in the multi-function device;

the image copying operation;

the image printing operation; and

the image transmitting operation;

associated with one or more image data stored in the one or more data store locations;

means for generating at least one bit mask; and

means for writing, upon the detection of at least one of the operations, at least a portion of the at least one generated bit mask to the one or more data store locations associated with the one or more stored image data.

12. The device of claim 11 wherein the means for generating at least one bit mask is a means for generating at least one pseudorandom bit mask.

13. The device of claim 11 wherein the means for generating at least one bit mask is a means for generating at least two pseudorandom bit masks.

14. The device of claim 11 wherein the image transmitting operation is a facsimile transmitting operation.

15. A method of bit masking image data on a nonvolatile data storage associated with a multi-function device, the method comprising the steps of:

testing for at least one of the following in the multi-function device;

an image scanning operation interruption;

an image copying operation interruption;

an image printing operation interruption;

an image transmitting operation interruption; and

associated with one or more image data from one or more locations on the nonvolatile data storage; and

if at least one of the tested interruptions is detected;

for two or more bit masking operations;

generating a bit mask; and

writing at least a portion of the generated bit mask to the one or more memory locations on the nonvolatile data associated with the one or more stored image data.

16. The method of claim 15 wherein the step of generating a bit mask is a step of generating a pseudorandom bit mask.

17. The method of claim 15 wherein the image transmitting operation is a facsimile transmitting operation.

18. A method of bit masking image data on a nonvolatile data storage associated with a multi-function device, the method comprising the steps of:

testing for at least one of the following in the multi-function device;

an image scanning operation interruption;

an image copying operation interruption;

an image printing operation interruption; and

an image transmitting operation interruption;

associated with one or more image data from one or more locations on the nonvolatile data storage; and

if at least one of the tested interruptions is detected;

generating at least one bit mask; and

for two or more bit masking operations;

writing at least a portion of the at least one generated bit mask to the one or more memory locations associated with the one or more stored image data.

19. The method of claim 18 wherein the step of generating at least one bit mask is a step of generating a pseudorandom bit mask.

20. The method of claim 18 wherein the image transmitting operation is a facsimile transmitting operation.

21. A multi-function device adapted to execute at least one of the following operations—

an image scanning operation, an image copying operation, an image printing operation, and an image transmitting operation, the device comprising;

a nonvolatile data storage having one or more data store locations for storing one or more image data;

means for detecting at least one of the following in the multi-function device;

the image scanning operation interruption;

the image copying operation interruption;

the image printing operation interruption; and

the image transmitting operation;

associated with one or more image data stored in the one or more data store locations;

means for generating at least one bit mask; and

means for writing, upon the detection of at least one of the interruptions, at least a portion of the at least one generated bit mask to the one or more data store locations associated with the one or more stored image data.

22. The device of claim 21 wherein the means for generating at least one bit mask is a means for generating at least one pseudorandom bit mask.

23. The device of claim 21 wherein the image transmitting operation is a facsimile transmitting operation.