Electronic device, content reproduction control method, program, storage medium, and integrated circuit
AssigneePanasonic Corporation
InventorsHideki Matsushima, Hiroshi Okuyama, Ryousuke Kobayashi, Tomoyuki Haga
Life of this patent
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Abstract
To play back a content while managing the right of use of the content, such as a total time of playback of the content, an electronic device stores right information in a right temporary storage unit 59 and judges whether or not use of the content is permitted, in a process of decoding a frame. Also, the electronic device updates the right information stored in the right temporary storage unit 59. When the frame to be played back is the one at a predetermined position in order, the electronic device stores the right information stored in the right temporary storage unit 59 into a storage area 20.
Claims16
An electronic device comprising:
- a storage unit storing right information used for managing whether or not a content can be played back, the right information being stored in a state protected from unauthorized accesses;
- a receiving unit including a microprocessor operable to receive, one by one, a plurality of frames that constitute the content in an encrypted state;
- a right judging unit including a microprocessor operable to judge whether or not the content is permitted to be played back, in accordance with the right information;
- a control unit including a microprocessor operable to (a) cause the right judging unit to perform the judgment each time an Nth frame, of the plurality of frames, is received by the receiving unit and a value N satisfies a predetermined judgment condition, the value N being a natural number indicating a position of a frame in an order of a playback of the plurality of frames constituting the content, (b) decrypt the Nth frame and cause the decrypted Nth frame to be played back, when the right judging unit judges that the content is permitted to be played back, and (c) restrict the playback of frames, of the plurality of frames, located after the Nth frame, when the right judging unit judges that the content is not permitted to be played back;
- and
- a tamper detection unit including a microprocessor operable to perform a tamper detection for a part of an application module that plays back the content, and each time a tamper is detected, sequentially change the part of the application module for which the tamper detection is to be performed,
- wherein the tamper detection unit performs the tamper detection for a first part of the application module when a value indicating a position of a currently received frame, of the plurality of frames received by the receiving unit, satisfies the predetermined judgment condition a first time, and performs the tamper detection for a second part, which is different from the first part, of the application module when the value indicating the position of the currently received frame, of the plurality of frames received by the receiving unit, satisfies the predetermined judgment condition a second time.
A content playback control method for use in an electronic device for controlling playback of a content, the electronic device including a storage unit storing right information used for managing whether or not a content can be played back, the right information being stored in a state protected from unauthorized accesses, the content playback control method comprising:
- receiving, one by one, a plurality of frames that constitute the content in an encrypted state;
- judging whether or not the content is permitted to be played back, in accordance with the right information;
- causing said judging to perform the judgment each time an Nth frame, of the plurality of frames, is received by said receiving and a value N satisfies a predetermined judgment condition, the value N being a natural number indicating a position of a frame in an order of a playback of the plurality of frames constituting the content;
- decrypting the Nth frame and causing the decrypted Nth frame to be played back, when said judging judges that the content is permitted to be played back;
- restricting the playback of frames, of the plurality of frames, located after the Nth frame, when said judging judges that the content is not permitted to be played back;
- and
- performing a tamper detection for a part of an application module that plays back the content, and each time a tamper is detected, sequentially changing the part of the application module for which the tamper detection is to be performed,
- wherein said performing of the tamper detection performs the tamper detection for a first part of the application module when a value indicating a position of a currently received frame, of the plurality of frames received by said receiving, satisfies the predetermined judgment condition a first time, and performs the tamper detection for a second part, which is different from the first part, of the application module when the value indicating the position of the currently received frame, of the plurality of frames received by said receiving, satisfies the predetermined judgment condition a second time.
A non-transitory computer-readable recording medium having a control program stored thereon, the control program for causing an electronic device to play back a content, the electronic device including a storage unit storing right information used for managing whether or not a content can be played back, the right information being stored in a state protected from unauthorized accesses, the control program causing a computer of the electronic device to execute a method comprising:
- receiving, one by one, a plurality of frames that constitute the content in an encrypted state;
- judging whether or not the content is permitted to be played back, in accordance with the right information;
- causing said judging to perform the judgment each time an Nth frame, of the plurality of frames, is received by said receiving and a value N satisfies a predetermined judgment condition, the value N being a natural number indicating a position of a frame in an order of a playback of the plurality of frames constituting the content;
- decrypting the Nth frame and causing the decrypted Nth frame to be played back, when said judging judges that the content is permitted to be played back;
- restricting the playback of frames, of the plurality of frames, located after the Nth frame, when said judging judges that the content is not permitted to be played back;
- and
- performing a tamper detection for a part of an application module that plays back the content, and each time a tamper is detected, sequentially changing the part of the application module for which the tamper detection is to be performed,
- wherein said performing of the tamper detection performs the tamper detection for a first part of the application module when a value indicating a position of a currently received frame, of the plurality of frames received by said receiving, satisfies the predetermined judgment condition a first time, and performs the tamper detection for a second part, which is different from the first part, of the application module when the value indicating the position of the currently received frame, of the plurality of frames received by said receiving, satisfies the predetermined judgment condition a second time.
An integrated circuit for use in an electronic device for playing back a content, the electronic device including a storage unit storing right information used for managing whether or not a content can be played back, the right information being stored in a state protected from unauthorized accesses, the integrated circuit comprising:
- a receiving unit including a microprocessor operable to receive, one by one, a plurality of frames that constitute the content in an encrypted state;
- a right judging unit including a microprocessor operable to judge whether or not the content is permitted to be played back, in accordance with the right information;
- a control unit including a microprocessor operable to (a) cause the right judging unit to perform the judgment each time an Nth frame, of the plurality of frames, is received by the receiving unit and a value N satisfies a predetermined judgment condition, the value N being a natural number indicating a position of a frame in an order of a playback of the plurality of frames constituting the content, (b) decrypt the Nth frame and cause the decrypted Nth frame to be played back, when the right judging unit judges that the content is permitted to be played back, and (c) restrict the playback of frames, of the plurality of frames, located after the Nth frame, when the right judging unit judges that the content is not permitted to be played back;
- and
- a tamper detection unit operable to perform a tamper detection for a part of an application module that plays back the content, and each time a tamper is detected, sequentially change the part of the application module for which the tamper detection is to be performed,
- wherein the tamper detection unit performs the tamper detection for a first part of the application module when a value indicating a position of a currently received frame, of the plurality of frames received by the receiving unit, satisfies the predetermined judgment condition a first time, and performs the tamper detection for a second part, which is different from the first part, of the application module when the value indicating the position of the currently received frame, of the plurality of frames received by the receiving unit, satisfies the predetermined judgment condition a second time.
Dependencies are inferred from the claim text.