Secure device having key management function and information processing apparatus

• US 20080075290A1
• Filed: 08/15/2007
• Published: 03/27/2008
• Est. Priority Date: 09/26/2006
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Hasegawa, Eiji, Nishiguchi, Naoki
• Granted Patent: US 7,978,857 B2
• Time in Patent Office: Days
• US Class Current: 380/278
• CPC Class Codes: G06F 21/107 License processing; Key processing
• CPC Class Codes: G06F 21/1083 Partial license transfers
• CPC Class Codes: G06F 21/602 Providing cryptographic facilities or services
• CPC Class Codes: G06F 21/72 in cryptographic circuits
• 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: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04L 9/0877 using additional device, e.g. trusted platform module [TPM], smartcard, USB or hardware security module [HSM]
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB

Abstract

A secure device has an input unit for dividing content into a plurality of blocks and inputting the plurality of blocks, a key generating unit for sequentially generating keys for encrypting one or plural blocks, a content encrypting unit for encrypting the one or plural blocks by using the generated key, a key information generating unit for generating key information for restoring the generated key used for the encrypting by the generated key, and a storage control unit for outputting contents of each of the blocks encrypted by the content encrypting unit and the key information generated by the key information generating unit to an external storage. The key sequentially generated by the key generating unit is newly generated when a predetermined condition is satisfied, and varies by every one or plural blocks.

Claims

1. A secure device comprising:

an input unit for dividing content into a plurality of blocks and inputting the plurality of blocks;

a key generating unit for sequentially generating keys for encrypting one or plural blocks;

a content encrypting unit for encrypting the one or plural blocks by using the generated key;

a key information generating unit for generating key information for restoring the generated key used for the encrypting by the generated key; and

a storage control unit for outputting contents of each of the blocks encrypted by the content encrypting unit and the key information generated by the key information generating unit to an external storage,

wherein the key sequentially generated by the key generating unit is newly generated when a predetermined condition is satisfied, and varies by every one or plural blocks.

2. The secure device according to claim 1, further comprising:

a restoration control unit for receiving key information stored in the external storage;

a key information restoring unit for restoring the generated key used for the encrypting from the received key information; and

an output unit for outputting the restored generated key to an information processing mechanism for decrypting contents of each of the blocks stored in the external storage.

3. The secure device according to claim 2, further comprising a key information restoration managing unit for managing a restoration state of the generated key which is restored by the key information restoring unit and, on the basis of the restoration state of the generated key already restored, determining whether the already restored generated key can be updated or not and whether a generated key to be newly restored can be restored or not,

wherein when it is determined that restoration is not permitted, the key information restoring unit does not restore the generated key which is not permitted to be restored.

4. The secure device according to claim 1, wherein the key information includes a generated key which is encrypted with a master key peculiar to the secure device.

5. The secure device according to claim 1, wherein the key information includes the generated key and range information specifying the block of contents to which the generated key is applied for encrypting.

6. The secure device according to claim 1, further comprising a key information storing unit for storing a key generated by the key generating unit,

wherein the key information includes a key index that specifies the generated key stored in the key information storing unit.

7. The secure device according to claim 6, wherein the key information further includes range information that specifies a block of contents to which the generated key specified by the key index is applied.

8. The secure device according to claim 1, wherein the key generating unit generates a key initial value and, from the key initial value, generates a key on the basis of a predetermined rule, and the key information includes the key initial value.

9. An information processing apparatus having a key management function and comprising:

a secure control unit having a function of generating and restoring a key for encrypting content and encrypting contents by using the generated key;

a content storing unit for storing the encrypted content and key information having data by which the generated key used for encrypting the content can be restored; and

an information processing unit for reproducing the contents stored in the content storing unit,

wherein the secure control unit comprises;

an input unit for dividing content into a plurality of blocks and inputting the plurality of blocks;

a key generating unit for sequentially generating keys for encrypting one or plural blocks when a predetermined condition is satisfied;

a content encrypting unit for encrypting the one or plural blocks by using the generated key;

a key information generating unit for generating key information for restoring the generated key used for the encrypting by the generated key;

a storage control unit for outputting contents of each of the blocks encrypted by the content encrypting unit and the key information generated by the key information generating unit to the content storing unit;

a restoration control unit for receiving key information for restoring the generated key used for the encrypting from the information processing unit;

a key information restoring unit for restoring the generated key used for the encrypting from the received key information; and

an output unit for outputting the restored generated key to the information processing unit, and

the information processing unit comprises;

an information obtaining unit for obtaining contents of a block to be reproduced and key information from the content storing unit;

a key obtaining unit for supplying the obtained key information to the secure control unit and obtaining a generated key corresponding to the key information from the secure control unit; and

a content restoring unit for reproducing content by sequentially restoring contents of the block obtained from the content storing unit by using the generated key obtained from the secure control unit.

10. A program for making a computer realize the key management function of the information processing apparatus according to claim 9.