Encryption device, key distribution device and key distribution system

A key distribution system that distributes key data for using content, the key distribution system comprising:

• an outsource destination encryption device;
• a key distribution device;
• and
• an outsource source encryption device operable to (i) receive first license information proving that the outsource source encryption device is permitted to use the content, (ii) generate second license information that includes the first license information and certification information proving that encryption of the content has been outsourced to the outsource destination encryption device, and (iii) transmit the generated second license information together with the content to the outsource destination encryption device,
• wherein the outsource destination encryption device is operable to (i) receive the second license information together with the content from the outsource encryption device, (ii) transmit the received second license information to a key distribution device, and (iii) receive the key data from the key distribution device, and
• wherein the key distribution system includes:
• an acquiring unit operable to acquire the second license information from the outsource destination encryption device;
• a first judging unit operable to perform a first judgment for judging, using the certification information, whether or not the encryption of the content has been outsourced from the outsource source encryption device to the outsource destination encryption device;
• a second judging unit operable to perform a second judgment for judging, using the first license information, whether or not the outsource source encryption device is permitted to use the content;
• and
• a transmission unit operable to transmit the key data to the outsource destination encryption device if a result of the first judgment and a result of the second judgment are in the affirmative.

An integrated circuit used in a key distribution device that distributes key data used in encryption of content to encryption devices, the integrated circuit comprising:

• an acquiring unit operable to acquire, from a second encryption device, second license information that includes (i) first license information proving that a first encryption device is permitted to use the content and (ii) certification information proving that encryption of the content has been outsourced from the first encryption device to the second encryption device;
• a first judging unit operable to perform a first judgment for judging, using the certification information, whether or not the encryption of the content has been outsourced from the first encryption device to the second encryption device;
• a second judging unit operable to perform a second judgment for judging, using the first license information, whether or not the first encryption device is permitted to use the content;
• and
• a transmission unit operable to transmit the key data to the second encryption device if a result of the first judgment and a result of the second judgment are in the affirmative.

A key distribution method used in a key distribution device that distributes key data used in encryption of content to encryption devices, the key distribution method comprising:

• acquiring, from a second encryption device, second license information that includes (i) first license information proving that a first encryption device is permitted to use the content and (ii) certification information proving that encryption of the content has been outsourced from the first encryption device to a second encryption device;
• performing a first judgment for judging, using the certification information, whether or not the encryption of the content has been outsourced from the first encryption device to the second encryption device;
• performing a second judgment for judging, using the first license information, whether or not the first encryption device is permitted to use the content;
• and
• transmitting the key data to the second encryption device if a result of the first judgment and a result of the second judgment are in the affirmative.

A non-transitory computer readable recording medium on which is recorded a key distribution program for causing a computer to function as a key distribution device that distributes key data used in encryption of content to encryption devices, wherein, when executed, the key distribution program causes the computer to function as:

• an acquiring unit operable to acquire, from a second encryption device, second license information that includes (i) first license information proving that a first encryption device is permitted to use the content and (ii) certification information proving that encryption of the content has been outsourced from the first encryption device to the second encryption device;
• a first judging unit operable to perform a first judgment for judging, using the certification information, whether or not the encryption of the content has been outsourced from the first encryption device to the second encryption device;
• a second judging unit operable to perform a second judgment for judging, using the first license information, whether or not the first encryption device is permitted to use the content;
• and
• a transmission unit operable to transmit the key data to the second encryption device if a result of the first judgment and a result of the second judgment are in the affirmative.