Security chip used in a contents data playing device, update management method, and update management program

1. A security chip used in a contents data playing device, the security chip comprising:

at least one hardware processor; and

a memory configured to store firmware data including a firmware update program and a firmware program;

the firmware update program causes the processor to:

determine whether an update process has been completed on the firmware data when a contents key acquisition instruction or a contents data playing instruction is input to the contents data playing device,

initiate a determination process to determine whether the firmware data needs to be updated based on a comparison between expiration information set in the firmware data and time information received via a network, the time information being encrypted together with a contents key;

decrypt the encrypted time information and confirm that the time information has not been hampered;

in response to a verification that an update process has been completed and a predetermined period has elapsed according to the comparison, determine that the updating of the firmware data is needed;

reject the contents key acquisition instruction or the contents data playing instruction when the firmware data needs to be updated; and

in response to the verification that an update process has been completed and a predetermined period has not elapsed according to the comparison, determine that the updating of the firmware data is not needed;

acquire, via the network, the contents key for decrypting contents data, and

decrypt the contents data by using the contents key.

2. The security chip according to claim 1 ,

wherein the firmware update program further causes the processor to

record, in an update state storage unit, update state information indicating a state of the update process in the update process performed on the firmware data, and

refer to the update state information in response to the request input to the security chip to acquire the contents key or to decrypt the contents data, and reject the request when the update state information indicates that the update process has not been completed.

3. The security chip according to claim 1 , wherein the firmware update program further causes the processor to determine whether the firmware data needs to be updated based on the comparison between the expiration information set in the firmware data and the time information received via the network when the update process has been completed on the firmware data.

4. A method of update management executed by a security chip included in a contents data playing device, the method comprising:

determining whether an update process has been completed on firmware data when a contents key acquisition instruction or a contents data displaying instruction is input to the contents data displaying device;

initiating a determination process to determine whether the firmware data needs to be updated based on a comparison between expiration information set in the firmware data and time information received via a network, the time information being encrypted together with a contents key;

decrypting the encrypted time information and confirming that the time information has not been hampered;

in response to a verification that an update process has been completed and a predetermined period has elapsed according to the comparison, determining that the updating of the firmware data is needed;

rejecting the contents key acquisition instruction or the contents data displaying instruction when the firmware data needs to be updated; and

in response to the verification that an update process has been completed and a predetermined period has not elapsed according to the comparison, determining that the updating of the firmware data is not needed;

acquiring, via the network, the contents key for decrypting contents data; and

decrypting the contents data by using the contents key.

5. The method according to claim 4 , further comprising:

recording, by the security chip, update state information in an update state storage unit, the update state information indicating a state of the update process in the update process performed on the firmware data, wherein

the recording includes referring to the update state information in response to the request input to the security chip to acquire the contents key or to decrypt the contents data, and rejecting the request when the update state information indicates that the update process has not been completed.

6. The method according to claim 4 , wherein whether the firmware data needs to be updated based on the comparison between the expiration information set in the firmware data and the time information received via the network is determined when the update process has been completed on the firmware data.

7. A non-transitory computer-readable recording medium storing a program for executing update management by a security chip included in a contents data playing device, the program causes a computer to execute a process comprising:

determining whether an update process has been completed on firmware data when a contents key acquisition instruction or a contents data displaying instruction is input to the contents data displaying device;

initiating a determination process to determine whether the firmware data needs to be updated based on a comparison between expiration information set in the firmware data and time information received via a network, the time information being encrypted together with a contents key;

decrypting the encrypted time information and confirming that the time information has not been hampered;

in response to a verification that an update process has been completed and a predetermined period has elapsed according to the comparison, determining that the updating of the firmware data is needed;

rejecting the contents key acquisition instruction or the contents data displaying instruction when the firmware data needs to be updated; and

in response to the verification that an update process has been completed and a predetermined period has not elapsed according to the comparison, determining that the updating of the firmware data is not needed;

acquiring, via the network, the contents key for decrypting contents data; and

decrypting the contents data by using the contents key.

8. The non-transitory computer-readable recording medium according to claim 7 , the process further comprising:

recording, by the security chip, update state information in an update state storage unit, the update state information indicating a state of the update process in the update process performed on the firmware data, wherein

the recording includes referring to the update state information in response to the request input to the security chip to acquire the contents key or to decrypt the contents data, and rejecting the request when the update state information indicates that the update process has not been completed.

9. The non-transitory computer-readable recording medium according to claim 7 , wherein whether the firmware data needs to be updated based on the comparison between the expiration information set in the firmware data and the time information received via the network is determined when the update process has been completed on the firmware data.