Motion picture data encrypting method and computer system and motion picture data encoding/decoding apparatus to which encrypting method is applied
AssigneeKabushiki Kaisha Toshiba
InventorYasuhiro Ishibashi
Life of this patent
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Abstract
Of I, P, and B pictures contained in an MPEG 2 data stream, only the I picture is subjected to encryption such as scramble processing. Scramble rule data used at that time is stored in the lead-in area of an optical disk. A software DVD decoder reads the scramble rule data stored in the lead-in area, and its certification control module descrambles only the I picture. With this processing, the CPU power required for descramble processing can be reduced, and motion picture data can be decoded by the software DVD decoder in real time.
Claims33
A motion picture data encrypting/decrypting method of encrypting digitally compressed/encoded motion picture data including an intraframe encoded image and an interframe predictive encoded image, thereby preventing illegal use of the motion picture data, comprising the steps of:
- performing scramble processing of calculating, of the digitally compressed/encoded motion picture data, the intraframe encoded image on the basis of a predetermined rule;
- storing the motion picture data including the intraframe encoded image having undergone the scramble processing in an optical disk as a program area of a data sequence constituted by a lead-in area, the program area, and a lead-out area, and storing a scramble rule representing a calculation rule for the scramble processing in the lead-in area;
- reading the motion picture data in the program area from said optical disk;
- and
- executing descramble calculation processing for the intraframe encoded image contained in the read motion picture data on the basis of scramble data, thereby decrypting the motion picture data, wherein the motion picture data sequence is constituted by a header portion and a data portion, and the header portion includes data representing a location of the intraframe encoded image having undergone the scramble processing.
A motion picture data encrypting/decrypting apparatus for encrypting digitally compressed/encoded motion picture data including an intraframe encoded image and an interframe predictive encoded image, thereby preventing illegal use of the motion picture data, comprising:
- means for performing scramble processing of calculating, of the digitally compressed/encoded motion picture data, the intraframe encoded image on the basis of a predetermined rule;
- means for storing the motion picture data including the intraframe encoded image having undergone the scramble processing in an optical disk as a program area of a data sequence constituted by a lead-in area, the program area, and a lead-out area, and storing a scramble rule representing a calculation rule for the scramble processing in the lead-in area;
- means for reading the motion picture data in the program area from said optical disk;
- and
- means for executing descramble calculation processing for the intraframe encoded image contained in the read motion picture data on the basis of scramble data, thereby decrypting the motion picture data, wherein the motion picture data sequence is constituted by a header portion and a data portion, and the header portion includes data representing a location of the intraframe encoded image having undergone the scramble processing.
A computer system comprising:
- a CPU;
- a disk drive device for reading data from a storage medium in which digitally compressed/encoded motion picture data is stored, the motion picture data being stored in an optical disk as a program area of a data sequence constituted by a lead-in area, a program area, and a lead-out area, and the lead-in area storing scramble rule data representing a calculation rule for the scramble processing;
- a disk interface capable of controlling said disk drive;
- means for causing said CPU to extract, of the motion picture data read from said disk drive device via said disk interface, the intraframe encoded image having undergone predetermined scramble processing in accordance with the calculation rule included in the lead-in area;
- and
- means for causing said CPU to execute descramble calculation processing for the extracted intraframe encoded image on the basis of the scramble rule data stored in the lead-in area, thereby decrypting the motion picture data, wherein the data sequence of the motion picture data is constituted by a header portion and a data portion, and the header portion includes data representing a location of the intraframe encoded image having undergone the scramble processing.
A method of encrypting a digitally compressed/encoded motion picture data stream, comprising:
- selecting units of the motion picture from the data stream;
- encrypting the selected units;
- and
- storing data indicating which units are encrypted in a header of the data stream.
A method of decrypting digitally compressed/encoded and partially encrypted motion picture data stream, the data stream being formed of a header and a plurality of packets, some packets being encrypted, and the header storing data indicating which packets are encrypted, comprising:
- reading data indicating which packets are encrypted from the header;
- and
- decrypting the encrypted packets indicated by the read data.
An apparatus for encrypting a digitally compressed/encoded motion picture data stream, comprising:
- means for selecting units of the motion picture from the data stream;
- means for encrypting the selected units;
- and
- means for storing data indicating which units are encrypted in a header of the data stream.
An apparatus for decrypting a digitally compressed/encoded and partially encrypted motion picture data stream, the data stream being formed of a header and a plurality of packets, some packets being encrypted, and the header storing data indicating which packets are encrypted, comprising:
- means for reading data indicating which packets are encrypted from the header;
- and
- means for decrypting the encrypted packets indicated by the read data.
A storage medium for storing a digitally compressed/encoded motion picture data stream, units of the motion picture from the data stream being selected, and the selected units being encrypted, comprising:
- means for storing data indicating which units are encrypted in a header of the data stream.
A storage medium for a digitally compressed/encoded and partially encrypted motion picture data stream, the data stream being formed of a header and a plurality of packets, some packets being encrypted, and the header storing data indicating which packets are encrypted, comprising:
- means for reading data indicating which packets are encrypted from the header, wherein the read data indicates how to decrypt the encrypted packets.
Dependencies are inferred from the claim text.