Information reproducing apparatus and secure module

• US 20030126457A1
• Filed: 11/27/2002
• Published: 07/03/2003
• Est. Priority Date: 12/27/2001
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Hasebe, Takayuki, Kohiyama, Kiyoshi
• Granted Patent: US 7,913,094 B2
• Time in Patent Office: Days
• US Class Current: 713/193
• 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 21/33 using certificates

Abstract

In an information reproducing apparatus having an open architecture, a secure module stores first information, and has a structure which does not allow access to the first information from outside, and a memory has a structure which can be accessed from outside. A decryption unit loaded in the memory decrypts an encryption applied to the first information by using a predetermined key. A key supply unit implemented in the secure module supplies the predetermined key to the decryption unit. An authentication unit implemented in the secure module supplies second information to the decryption unit, refers to third information returned in response to the second information, and checks for authenticity of the decryption unit. A key-supply stop unit implemented in the secure module stops supply of the predetermined key by the key supply unit when the authentication unit does not authenticate the decryption unit.

Claims

1. An information reproducing apparatus for reproducing information which is transmitted through a transmission medium or stored in a recording medium, comprising:

a secure module storing first information and having a structure which does not allow access to the first information from outside;

a memory which can be accessed from outside;

decryption unit which is loaded in the memory, and decrypts an encryption applied to the first information by using a predetermined key;

key supply unit which is implemented in the secure module, and supplies the predetermined key to the decryption unit;

authentication unit which is implemented in the secure module, supplies second information to the decryption unit, refers to third information returned in response to the second information, and checks for authenticity of the decryption unit, where the second information is predetermined; and

key-supply stop unit which is implemented in the secure module, and stops supply of the predetermined key by the key supply unit when the authentication unit does not authenticate the decryption unit.

2. The information reproducing apparatus according to claim 1, wherein the authentication unit changes an initial value of the second information every time the information reproducing apparatus is started up.

3. The information reproducing apparatus according to claim 1, wherein the authentication unit has a plurality of protocols for checking for authenticity of the decryption unit, and changes a currently used protocol from one to another of the plurality of protocols at predetermined time intervals.

4. The information reproducing apparatus according to claim 1, wherein the key supply unit stops the supply of the predetermined key when the third information is not returned from the decryption unit in a predetermined time.

5. The information reproducing apparatus according to claim 1, wherein the key supply unit stops the supply of the predetermined key when more than one identical response is successively returned from the decryption unit.

6. The information reproducing apparatus according to claim 1, wherein the decryption unit, the key supply unit, the authentication unit, and the key-supply stop unit are, in advance, encrypted and stored in a recording medium, and encryptions applied to the decryption unit, the key supply unit, the authentication unit, and the key-supply stop unit are decrypted and loaded in the memory or the secure module as necessary.

7. The information reproducing apparatus according to claim 1, wherein the decryption unit is loaded in the memory in a different manner on every loading operation.

8. The information reproducing apparatus according to claim 7, wherein the decryption unit is loaded in a different region of the memory on every loading operation.

9. The information reproducing apparatus according to claim 7, wherein the decryption unit is loaded in the memory so that the decryption unit uses a different region of the memory on every loading operation.

10. The information reproducing apparatus according to claim 7, wherein the decryption unit is loaded in the memory so that the decryption unit uses a different register on every loading operation.

11. The information reproducing apparatus according to claim 1, further comprising,

output unit which outputs the first information after the first information is decrypted by the decryption unit, and

encryption unit which reencrypts the first information after the first information is decrypted by the decryption unit before the first information is output by the output unit.

12. The information reproducing apparatus according to claim 11, wherein the encryption unit selects one of a plurality of protocols for reencrypting the first information after the first information is decrypted by the decryption unit.

13. The information reproducing apparatus according to claim 12, wherein the encryption unit is realized by loading a program stored in the secure module, in the memory.

14. The information reproducing apparatus according to claim 1, wherein a plurality of unit loaded in the memory set an interruption prohibit flag in order to prohibit interruption by another program when the plurality of unit operate.

15. The information reproducing apparatus according to claim 1, wherein every time a program stored in the secure module is loaded in the memory, the program is encrypted in a different manner and supplied to the memory.

16. The information reproducing apparatus according to claim 1, wherein the secure module is constituted by a detachable device.

17. A secure module capable of being detachably mounted on an information reproducing apparatus and executing processing related to security when the information reproducing apparatus reproduces information which is transmitted through a transmission medium or stored in a recording medium, where the information reproducing apparatus includes a memory which can be accessed from outside, and decryption unit which is loaded in the memory, and decrypts an encryption applied to the first information by using a predetermined key;

the secure module comprising;

key supply unit which is implemented in the secure module, and supplies the predetermined key to the decryption unit;

authentication unit which is implemented in the secure module, supplies second information to the decryption unit, refers to third information returned in response to the second information, and checks for authenticity of the decryption unit, where the second information is predetermined; and

key-supply stop unit which is implemented in the secure module, and stops supply of the predetermined key by the key supply unit when the authentication unit does not authenticate the decryption unit.

18. An information reproducing method for reproducing information which is transmitted through a transmission medium or stored in a recording medium, comprising:

a secure module storing first information and having a structure which does not allow access to the first information from outside;

a memory which can be accessed from outside;

decryption unit which is loaded in the memory, and decrypts an encryption applied to the first information by using a predetermined key;

key supply unit which is implemented in the secure module, and supplies the predetermined key to the decryption unit;

authentication unit which is implemented in the secure module, supplies second information to the decryption unit, refers to third information returned in response to the second information, and checks for authenticity of the decryption unit, where the second information is predetermined; and

key-supply stop unit which is implemented in the secure module, and stops supply of the predetermined key by the key supply unit when the authentication unit does not authenticate the decryption unit.

19. The information reproducing method according to claim 18, wherein the authentication unit changes an initial value of the second information every time the information reproducing apparatus is started up.

20. The information reproducing method according to claim 18, wherein the authentication unit has a plurality of protocols for checking for authenticity of the decryption unit, and changes a currently used protocol from one to another of the plurality of protocols at predetermined time intervals.

21. The information reproducing method according to claim 18, wherein the key supply unit stops the supply of the predetermined key when the third information is not returned from the decryption unit in a predetermined time.

22. The information reproducing method according to claim 18, wherein the key supply unit stops the supply of the predetermined key when more than one identical response is successively returned from the decryption unit.

23. The information reproducing method according to claim 18, wherein the decryption unit, the key supply unit, the authentication unit, and the key-supply stop unit are, in advance, encrypted and stored in a recording medium, and encryptions applied to the decryption unit, the key supply unit, the authentication unit, and the key-supply stop unit are decrypted and loaded in the memory or the secure module as necessary.

24. The information reproducing method according to claim 18, wherein the decryption unit is loaded in the memory in a different manner on every loading operation.

25. The information reproducing method according to claim 18, wherein the decryption unit is loaded in a different region of the memory on every loading operation.

26. The information reproducing method according to claim 18, wherein the decryption unit is loaded in the memory so that the decryption unit uses a different region of the memory on every loading operation.

27. The information reproducing method according to claim 18, wherein the decryption unit is loaded in the memory so that the decryption unit uses a different register on every loading operation.

28. The information reproducing method according to claim 18, further comprising,

output unit which outputs the first information after the first information is decrypted by the decryption unit, and

encryption unit which reencrypts the first information after the first information is decrypted by the decryption unit before the first information is output by the output unit.

29. The information reproducing method according to claim 28, wherein the encryption unit selects one of a plurality of protocols for reencrypting the first information after the first information is decrypted by the decryption unit.

30. The information reproducing method according to claim 29, wherein the encryption unit is realized by loading a program stored in the secure module, in the memory.

31. The information reproducing method according to claim 18, wherein a plurality of unit loaded in the memory set an interruption prohibit flag in order to prohibit interruption by another program when the plurality of unit operate.

32. The information reproducing method according to claim 18, wherein every time a program stored in the secure module is loaded in the memory, the program is encrypted in a different manner and supplied to the memory.

33. The information reproducing method according to claim 18, wherein the secure module is constituted by a detachable device.