Storage and access control method for storage

• US 20060282696A1
• Filed: 06/14/2006
• Published: 12/14/2006
• Est. Priority Date: 06/14/2005
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Hitachi Global Storage Technologies Netherlands BV (Western Digital Corporation)
• Inventors: Inagaki, Yukihide
• Granted Patent: US 7,716,509 B2
• Time in Patent Office: Days
• US Class Current: 713/600
• CPC Class Codes: G06F 1/14 Time supervision arrangements, e.g. real time clock
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 21/79 in semiconductor storage media, e.g. directly-addressable memories
• CPC Class Codes: G06F 21/80 in storage media based on magnetic or optical technology, e.g. disks with sectors preventing unauthorised reproduction or copying of disc-type recordable media G11B20/00
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00492 wherein content or user data is encrypted
• CPC Class Codes: G11B 20/0084 wherein the usage restriction can be expressed as a specific time or date
• CPC Class Codes: G11B 20/00847 wherein the usage restriction is defined by a licence file

Abstract

Embodiments of the invention prevent a storage from being continuously used in a state in which the time of a built-in clock is different from the actual time because of replacement of a battery or intentional tampering of time. In one embodiment, a storage having a recording medium for storing content data includes: a clock that can refer to present time and can set time to reliable standard time on the outside (time synchronization); a built-in power supply that supplies power to the clock; and a nonvolatile memory that records time when the time synchronization for the clock is performed. The storage compares, according to circumstances, the present time indicated by the built-in clock and the time when the time synchronization is performed last time and, when it is made clear that the time synchronization is not performed for time longer than a fixed time set in advance, prohibits an access to a limited access area of the recording medium.

Claims

1. A storage, comprising:

a recording medium;

a built-in power supply;

a clock that can operate with power from the built-in power supply or an external power supply and set time to standard time;

a nonvolatile memory that stores time when the clock sets time; and

a subtracter that outputs time, which has elapsed since time setting was performed last, on the basis of the time setting time stored in the nonvolatile memory and time information obtained from the clock,

wherein when the output of the subtracter exceeds a predetermined fixed time, the storage blocks an entire recording area or a part of the recording area of the recording medium against a readout request from an apparatus on the outside.

2. A storage according to claim 1, wherein a second threshold value smaller than the fixed time is further set in advance and, when the output of the subtracter is between the second threshold value and the fixed time, the storage warns the apparatus on the outside that time setting for the clock is necessary.

3. A storage according to claim 2, wherein, when the output of the subtracter does not exceed the second threshold value, the storage releases the block for the entire recording area or the part of the recording area of the storage medium.

4. A storage according to claim 1, wherein the recording medium has a limited access area and a usual recording area, and the block against a readout request from the apparatus on the outside is applied to the limited access area.

5. A storage according to claim 4, wherein the limited access area is an anti-tamper area for which equipment authentication is necessary prior to an access.

6. A storage according to claim 4, wherein content data is recorded in the usual recording area, and license information of the content data is recorded in the limited access area.

7. An access control method for a storage, comprising:

calculating time, which has elapsed since time setting was performed last, on the basis of present time of a clock, which can operate with power supply from a built-in power supply or an external power supply and set time to standard time, and time when the time setting is performed;

judging whether the elapsed time exceeds a second threshold value smaller than a first threshold value;

judging, when the elapsed time exceeds the second threshold value, whether the elapsed time exceeds the first threshold value;

blocking, when the elapsed time exceeds the first threshold value, a limited access area of a recording medium against an access request from an apparatus on the outside;

warning, when the elapsed time exceeds the second threshold value and does not exceed the first threshold value, the apparatus on the outside that time setting for the clock is necessary; and

releasing, when the elapsed time does not exceed the second threshold value, the blocking for the limited access area of the recording medium.

8. An access control method according to claim 7, wherein the limited access area is an anti-tamper area for which equipment authentication is necessary prior to an access.

9. An access control method according to claim 7, wherein the recording medium has the limited access area and a usual recording area, and the block against a readout request from the apparatus on the outside is applied to the limited access area, and wherein content data is recorded in the usual recording area, and license information of the content data is recorded in the limited access area.

10. A storage, comprising:

a recording medium having a limited access area, in which fixed form information including expiration date information is stored, in a part of a recording area;

a built-in power supply;

a clock that can operate with power from the built-in power supply or an external power supply and set time to standard time;

a nonvolatile memory that stores time when the clock sets time;

a subtracter that outputs time, which has elapsed since time setting was performed last, on the basis of the time setting time stored in the nonvolatile memory and time information obtained from the clock;

a judging device that permits an access to the limited access area of the recording medium when the output of the subtracter does not exceed a preset fixed time; and

a time comparator that compares expiration date information included in the fixed form information, which is read out after the judging device permit the access, and present time obtained from the clock,

wherein when the present time does not reach the expiration date, the storage continues readout of the fixed form information and, when the present time reaches the expiration date, the storage stops the readout of the fixed form information.

11. A storage according to claim 10, wherein the storage erases the fixed form information after the readout of the fixed form information is stopped.

12. A storage according to claim 10, wherein the fixed form information comprises license information for content data stored in the recording medium.

13. A storage according to claim 12, wherein the license information includes encryption and decryption keys for the context data stored in the recording medium.

14. A storage according to claim 12, wherein the license information includes copy control information for the content data stored in the recording medium.

15. An access control method for a storage, comprising:

calculating time which has elapsed since time setting was performed last, on the basis of present time of a clock, which can operate with power supply from a built-in power supply or an external power supply and set time to standard time, and time when the time setting is performed;

judging whether the elapsed time exceeds a second threshold value smaller than a first threshold value;

judging, when the elapsed time exceeds the second threshold value, whether the elapsed time exceeds the first threshold value;

blocking, when the elapsed time exceeds the first threshold value, a limited access area of a recording medium against an access request from an apparatus on the outside;

warning, when the elapsed time exceeds the second threshold value and does not exceed the first threshold value, the apparatus on the outside that time setting for the clock is necessary;

releasing, when the elapsed time does not exceed the second threshold value, the blocking for the limited access area of the recording medium;

reading out, when the block of the limited access area is released and a readout request is applied to the limited access area, fixed information recorded in the limited access information;

comparing expiration date information included in the fixed form information and present time obtained from the clock;

continuing, when the present time does not reach the expiration date, the readout of the fixed form information; and

stopping, when the present time reaches the expiration date, the readout of the fixed form information.

16. An access control method for a storage according to claim 15, further comprising erasing the fixed form information after stopping the readout of the fixed form information.

17. An access control method for a storage according to claim 15, wherein the fixed form information is license information for content data stored in the recording medium.

18. An access control method for a storage according to claim 15, wherein the license information includes encryption and decryption keys for the context data stored in the recording medium.

19. An access control method for a storage according to claim 15, wherein the license information includes copy control information for the content data stored in the recording medium.