Information processor having information dispersing function

• US 20070266261A1
• Filed: 05/07/2007
• Published: 11/15/2007
• Est. Priority Date: 05/12/2006
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Yasaki, Kouichi, Nishiguchi, Naoki
• Granted Patent: US 7,818,579 B2
• Time in Patent Office: Days
• US Class Current: 713/193
• CPC Class Codes: G06F 21/6209 to a single file or object, e.g. in a secure envelope, encrypted and accessed using a key, or with access control rules appended to the object itself
• CPC Class Codes: G06F 2221/2107 File encryption
• CPC Class Codes: H04L 9/085 Secret sharing or secret splitting, e.g. threshold schemes
• CPC Class Codes: H04L 9/0894 Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage

Abstract

An information processor has an information dispersing function, a dividing unit for dividing a first data (DT0) into n pieces of disperse information, and executing secret sharing scheme capable of restoring the first data (DT0) by using arbitrary k pieces (1<k<n) of disperse information out of the n pieces of disperse information, a first storage control unit for storing the arbitrary k pieces of disperse information generated by the dividing unit into plurality of portable recording devices, an editing unit for reconstructing the first data (DT0) by using the k pieces of disperse information stored in the plurality of recording devices and editing the restored first data (DT0), a difference generating unit, after the dividing unit divides a second data which is post-data (DT1) originated in the restored first data into n pieces of post-edit disperse information, for calculating the difference between post-edit disperse information corresponding to the recording device and pre-edit disperse information which has been stored in the recording device, and a second storage control unit for storing, for each of the recording devices, the post-edit disperse information of the recording device and the difference corresponding to the other recording devices.

Claims

1. An information processor having an information dispersing function, comprising:

a dividing unit for dividing a first data into n pieces of disperse information, and executing secret sharing scheme capable of restoring the first data by using arbitrary k pieces (1<

k<

n) of disperse information out of the n pieces of disperse information;

a first storage control unit for storing the arbitrary k pieces of disperse information out of the disperse information generated by the dividing unit into plurality of recording devices;

an editing unit for reconstructing the first data by using the k pieces of disperse information stored in the plurality of recording devices and editing the restored first data;

a difference generating unit, after the dividing unit divides a second data which is post-edit data originated in the restored first date into n pieces of post-edit disperse information, for calculating the difference between post-edit disperse information corresponding to the recording device and pre-edit disperse information which has been stored in the recording device; and

a second storage control unit for storing, for each of the recording devices, the post-edit disperse information of the recording device and the difference corresponding to the other recording devices.

3. The information processor according to claim 1, wherein the recording device is a portable recording medium which is detachable from the information processor and, by connecting the recording medium, an editing work can be performed.

4. The information processor according to claim 3, wherein the remaining (n−

k) pieces of disperse information which are not stored in the plurality of recording devices out of the n pieces of disperse information generated by the dividing unit are stored in (n−

k) pieces of not-carried information devices in a one-to-one corresponding manner, one of the not-carried information devices is a file server, and all of the n pieces of disperse information generated by the dividing unit are stored in the file server before the recording devices are carried out.

6. The information processor according to claim 4 or 5, wherein the pre-edit disperse information is carry-out disperse information generated by the dividing unit before the recording device is carried out.

7. The information processor according to claim 4 or 5, wherein when the pre-edit disperse information is carry-out disperse information generated by the dividing unit before the recording device is carried out, the second storage control unit stores the carry-out disperse information and the difference generated by the difference generating unit in each of the recording devices, but does not store the post-edit disperse information.

8. The information processor according to claim 4 or 5, wherein the pre-edit disperse information is post-edit disperse information generated in an editing operation of last time, the difference is calculated from the post-edit disperse information and the pre-edit disperse information and, when the editing operation is performed a plurality of times, all of differences calculated for the editing operations of the plurality of times are stored.

9. The information processor according to claim 4 or 5, wherein the portable recording medium is any of a flash memory, a USB memory, a magneto-optical recording medium, a magnetic recording medium, and a network storage.

10. The information processor according to claim 4, further comprising a reconstructing unit for generating post-edit disperse information corresponding to the k pieces of recording devices from disperse information corresponding to the k pieces of recording devices stored in the file server and the differences corresponding to the recording devices stored by the second storage control unit after editing, and reconstructing the post-edit data from the generated k pieces of post-edit disperse information.

11. The information processor according to claim 10, further comprising an updating unit for storing n pieces of post-edit disperse information into corresponding k pieces of recording devices and (n−

k) pieces of information devices, wherein the n pieces of post-edit disperse information are the information obtained by dividing the post-edit data reconstructed by the reconstructing unit into n pieces by the dividing unit.

19. An information processor according to claim 1 or 2, wherein the plurality of recording devices are k pieces of portable recording devices.

2. An information processor having an information dispersing function, comprising:

a dividing unit for dividing a first data into n pieces of disperse information, and executing secret sharing scheme capable of restoring the first data by using arbitrary k pieces (1<

k<

n) of disperse information out of the n pieces of disperse information;

a first storage control unit for storing the arbitrary k pieces of disperse information, out of the disperse information generated by the dividing unit into plurality of recording devices;

an editing unit for reconstructing the first data by using the k pieces of disperse information stored in the plurality of recording devices and editing the restored first data;

a difference generating unit, after the dividing unit divides a second data which is post-edit data originated in the restored first data into n pieces of post-edit disperse information, for calculating the difference between (n−

k) pieces of post-edit disperse information which do not correspond to any of the recording devices and (n−

k) pieces of pre-edit disperse information which do not correspond to any of the recording devices; and

wherein (n−

k) pieces of pre-edit disperse information obtain from the restored first data, and

a second storage control unit for storing, for each of the recording devices, the post-edit disperse information of the recording device and the difference.

5. The information processor according to claim 2, wherein the recording device is a portable recording medium,

the remaining (n−

k) pieces of disperse information which are not stored in the plurality of recording devices out of the n pieces of disperse information generated by the dividing unit are stored in (n−

k) pieces of not-carried information devices in a one-to-one corresponding manner, and the (n−

k) pieces of differences correspond to the (n−

k) pieces of information devices in a one-to-one corresponding manner.

12. The information processor according to claim 5, further comprising an updating unit for generating post-edit disperse information corresponding to the not-carried (n−

k) pieces of information devices from (n−

k) pieces of differences generated by the difference generating unit and (n−

k) pieces of disperse information stored in the not-carried (n−

k) pieces of information devices, and storing the generated post-edit disperse information into the corresponding (n−

k) pieces of information devices.

13. A program of an information processor for making a computer realize:

a dividing function of dividing a first data into n pieces of disperse information, and executing secret sharing scheme capable of restoring the first data by using arbitrary k pieces (1<

k<

n) of disperse information out of the n pieces of disperse information;

a first storage control function of storing the arbitrary k pieces of disperse information out of the n pieces of disperse information generated into plurality of different recording devices;

an editing function of reconstructing the first data by using the k pieces of disperse information stored in the recording devices and editing the restored first data;

a difference generating function, after division of post-edit data into n pieces of post-edit disperse information, of calculating the difference between post-edit disperse information corresponding to the recording device and pre-edit disperse information which has been stored in the recording device; and

a second storage control function of storing, for each of the recording devices, the post-edit disperse information of the recording device and the difference corresponding to the other recording devices.

14. A program of an information processor for making a computer realize:

a dividing function of dividing a first data into n pieces of disperse information, and executing secret sharing scheme capable of restoring the first data DT0 by using arbitrary k pieces (1<

k<

n) of disperse information out of the n pieces of disperse information;

a first storage control function of storing the arbitrary k pieces of disperse information out of the n pieces of disperse information generated into plurality of different recording devices;

an editing function of reconstructing the first data by using the k pieces of disperse information stored in the plurality of recording devices and editing the restored first data;

a difference generating function, after division of post-edit data to n pieces of post-edit disperse information, of calculating the difference between (n−

k) pieces of post-edit disperse information which do not correspond to any of the recording devices and (n−

k) pieces of pre-edit disperse information which do not correspond to any of the recording devices; and

wherein (n−

k) pieces of pre-edit disperse information obtain from the restored first data, and

a second storage control function of storing, for each of the recording devices, the post-edit disperse information of the recording device and the difference.

15. An information dispersing and storing system comprising an information processor capable of editing a first data, a plurality of portable recording devices, and a file server connected to the information processor via a network,

wherein the information processor comprises:

a dividing unit for dividing the first data into n pieces of disperse information, and executing secret sharing scheme capable of restoring the first data by using arbitrary k pieces (1<

k<

n) of disperse information out of the n pieces of disperse information;

a first storage control unit for storing the arbitrary k pieces of disperse information out of the disperse information generated by the dividing unit into plurality of different portable recording devices;

an editing unit for reconstructing the first data by using the k pieces of disperse information stored in the plurality of recording devices and editing the restored first data;

a difference generating unit, after the dividing unit divides a second data which is post-edit data originated in the restored first data into n pieces of post-edit disperse information, for calculating the difference between post-edit disperse information corresponding to the recording device and pre-edit disperse information which has been stored in the recording device; and

a second storage control unit for storing, for each of the recording devices, the post-edit disperse information of the recording device and the difference corresponding to the other recording devices,

when the recording device and the information processor are carried out, all of carry-out disperse information generated by the dividing unit before carry-out is stored in the file server,

in each of the recording devices, carry-out disperse information generated by the dividing unit before carry-out and corresponding to the recording device is stored, and

after the editing process by the editing unit, post-edit disperse information corresponding to the recording device and the difference is stored by the second storage control unit.

16. The information dispersing and storing system according to claim 15, further comprising a reconstructing unit, when a recording device A out of the carried recording devices is lost, for generating post-edit disperse information corresponding to the recording device A by using carry-out disperse information corresponding to the recording device A and stored in the file server and the differences corresponding to the recording device A and stored by the recording devices other than the recording device A,

and reconstructing post-edit data from post-edit disperse information corresponding to the recording devices other than the recording device A and stored in the other recording devices and the generated post-edit disperse information corresponding to the recording device A.

17. An information dispersing and storing system comprising an information processor capable of editing a first data, a plurality of portable recording devices, and a file server connected to the information processor via a network,

wherein the information processor comprises:

a dividing unit for dividing the first data into n pieces of disperse information, and executing secret sharing scheme capable of restoring the first data by using arbitrary k pieces (1<

k<

n) of disperse information out of the n pieces of disperse information;

a first storage control unit for storing the arbitrary k pieces of disperse information which can be carried, out of the disperse information generated by the dividing unit into plurality of recording devices;

an editing unit for reconstructing the first data by using the k pieces of disperse information stored in the plurality of recording devices and editing the restored first data;

a difference generating unit, after the dividing unit divides a second data which is post-edit data originated in the restored first data into n pieces of post-edit disperse information, for calculating the difference between (n−

k) pieces of post-edit disperse information which do not correspond to any of the recording devices and (n−

k) pieces of pre-edit disperse information which do not correspond to any of the recording devices; and

wherein (n−

k) pieces of pre-edit disperse information obtain from the restored data DT0, and

a second storage control unit for storing, for each of the recording devices, the post-edit disperse information of the recording device and the difference, and

when the recording devices and the information processor are carried out, carry-out disperse information generated by the dividing unit before carry-out and corresponding to the file server and the recording devices is stored in the file server and the recording devices.

18. The information dispersing and storing system according to claim 17, further comprising a reconstructing unit, when a recording device A out of the carried recording devices is lost, for generating post-edit disperse information corresponding to the file server by using carry-out disperse information corresponding to the file server and stored in the file server and the difference corresponding to the file server and stored in the recording device other than the recording device A,

and reconstructing post-edit data from post-edit disperse information corresponding to the recording devices other than the recording device A and stored in the other recording devices and the generated post-edit disperse information corresponding to the file server.