EP1825470A1 - Procede et dispositif pour ecrire et utiliser des cles servant a chiffrer/dechiffrer du contenu, et support d'enregistrement stockant les cles ecrites a l'aide du procede - Google Patents

Procede et dispositif pour ecrire et utiliser des cles servant a chiffrer/dechiffrer du contenu, et support d'enregistrement stockant les cles ecrites a l'aide du procede

Info

Publication number
EP1825470A1
EP1825470A1 EP05823731A EP05823731A EP1825470A1 EP 1825470 A1 EP1825470 A1 EP 1825470A1 EP 05823731 A EP05823731 A EP 05823731A EP 05823731 A EP05823731 A EP 05823731A EP 1825470 A1 EP1825470 A1 EP 1825470A1
Authority
EP
European Patent Office
Prior art keywords
data
encryption keys
recording medium
clips
continuous playback
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP05823731A
Other languages
German (de)
English (en)
Other versions
EP1825470A4 (fr
Inventor
Sung Wan Park
Byung Jin Kim
Kang Soo Seo
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LG Electronics Inc
Original Assignee
LG Electronics Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR1020050105754A external-priority patent/KR20060066627A/ko
Application filed by LG Electronics Inc filed Critical LG Electronics Inc
Publication of EP1825470A1 publication Critical patent/EP1825470A1/fr
Publication of EP1825470A4 publication Critical patent/EP1825470A4/fr
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
    • G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
    • G11B27/19—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier
    • G11B27/28—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
    • G11B20/0021—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
    • G11B20/0021—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier
    • G11B20/00217—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier the cryptographic key used for encryption and/or decryption of contents recorded on or reproduced from the record carrier being read from a specific source
    • G11B20/00253—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier the cryptographic key used for encryption and/or decryption of contents recorded on or reproduced from the record carrier being read from a specific source wherein the key is stored on the record carrier
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
    • G11B20/0021—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier
    • G11B20/0042—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier the copy protection scheme being related to a specific access protection standard
    • G11B20/00427—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier the copy protection scheme being related to a specific access protection standard advanced access content system [AACS]
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
    • G11B20/0021—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier
    • G11B20/00485—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier characterised by a specific kind of data which is encrypted and recorded on and/or reproduced from the record carrier
    • G11B20/00492—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier characterised by a specific kind of data which is encrypted and recorded on and/or reproduced from the record carrier wherein content or user data is encrypted
    • G11B20/00528—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier characterised by a specific kind of data which is encrypted and recorded on and/or reproduced from the record carrier wherein content or user data is encrypted wherein each title is encrypted with a separate encryption key for each title, e.g. title key for movie, song or data file
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
    • G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
    • G11B27/102—Programmed access in sequence to addressed parts of tracks of operating record carriers
    • G11B27/105—Programmed access in sequence to addressed parts of tracks of operating record carriers of operating discs

Definitions

  • This invention relates to a method for writing and using keys for copy-protecting a content recorded on a recording medium and a recording medium storing keys written by the method.
  • the DVD-ROM which is usually called the DVD, has a storage capacity of 4.7 GB and is commonly used as a storage medium for delivering high-quality digital contents such as movies .
  • TV stations currently broadcast in both analog and digital but only digital TV broadcast will be available in the near future.
  • Digital broadcast provides better video quality over its analog counterpart.
  • Viewers have a natural desire to enjoy movies of higher video quality than that of the DVD. For this reason, read-only and rewritable disks having higher storage capacity than the DVD are under development . Higher-capacity disks can provide viewers with high-quality contents in various and easy ways .
  • the copyright of contents recorded on recording media such as optical disks is sometimes infringed by illegal copying.
  • content data recorded on a recording medium is encrypted and the key used for the encryption is recorded in a particular area of the recording medium (e.g., an area that is not accessible by ordinary read operations) or the key itself or a method for obtaining the key is stored in a certified remote server.
  • More than one title may be recorded on a single DVD but the data of a title does not overlap with the data of another title.
  • each title may be encrypted using different keys for enhancing copy protection.
  • the present invention encrypts or decrypts data clips by selectively applying a plurality of encryption keys to the whole or partial data of each of the data clips.
  • the present invention stores a plurality of encryption keys used for encrypting a plurality of data clips in a key file and places index information for associating each of the plurality of encryption keys with a data segment encrypted with the encryption key in the key file or in another management information file.
  • each of a plurality of encryption keys is used for encrypting or decrypting each of data blocks organized by dividing each of a plurality of data clips with the boundaries of data segments shared by multiple titles.
  • each of a plurality of encryption keys is used for encrypting or decrypting each of a plurality of data clips. In yet another embodiment of the invention, each of a plurality of encryption keys is used for encrypting or decrypting each of data segments pointed to by playitems included in titles.
  • the index information is written in the clip information file storing information on each data clip.
  • the index information is written in the key file storing encryption keys
  • each index information set comprises a pair of information for allowing the access to the associated key and a data clip file name.
  • each index information set comprises a pair of the associated key and a data clip file name.
  • an index information set is created for each of data clips belonging to each title.
  • an index information set is created for each of playitems belonging to each title.
  • a plurality of encryption keys is obtained from a recording medium having content , data thereon.
  • a plurality of encryption keys is obtained from an external server through a network.
  • FIG. 1 illustrates an exemplary relation between a plurality of titles and a plurality of data clip files
  • FIG. 2 illustrates a block diagram of an apparatus for manufacturing read-only recording media having encryption information in accordance with an embodiment of the present invention
  • FIG. 3 illustrates an exemplary relation between a plurality of titles and a plurality of data clip files in which a different encryption key is applied to each of data segments divided in accordance with one embodiment of the present invention
  • FIG. 4 illustrates a data structure for storing encryption information in accordance with the embodiment shown in FIG. 3;
  • FIG. 5 illustrates an exemplary relation between a plurality of titles and a plurality of data clip files in which a different encryption key is applied to each of data segments divided in accordance with another embodiment of the present invention
  • FIGS. 6a and 6b illustrate data structures for storing encryption information in accordance with the embodiment shown in FIG. 5;
  • FIG. 7 illustrates an exemplary relation between a plurality of titles and a plurality of data clip files in which a different encryption key is applied to each of data segments divided in accordance with yet another embodiment of the present invention
  • FIGS. 8a, 8b, and 8c illustrate data structures for storing encryption information in accordance with the embodiment shown in FIG. 7;
  • FIG. 9 illustrates a block diagram of an apparatus for reproducing a recording medium storing encrypted content data and encryption information in accordance with an embodiment of the present invention.
  • Higher-capacity disk media e.g., Blu-ray Disk ROM, BD-
  • ROM in short do not manage each clip file containing A/V data as a title, which is exemplified in FIG. 1.
  • one movie playlist is managed as one title (logical continuous playback unit information) in the BD-ROM and each playitem included therein references the whole or a segment of a clip file.
  • the segments of the clip file that correspond to playitems may overlap.
  • the data segment referenced by playitem H 2 overlaps in part with the data segment referenced by playitem 13i.
  • the data segment referenced by playitem 12i overlaps in part with the data segment referenced by playitem 13 2 .
  • Title #1 and Title #3 have an overlapped segment 1Oi and Title #2 and Title #3 have an overlapped segment 1O 2 .
  • Titles having overlapped segments cannot be encrypted using different keys. If two titles sharing the same segment are encrypted with different keys, the shared segment should be decrypted with two different keys. For example, the overlapped segment 1Oi of Title #1 should be encrypted with two different keys and thus it should be decrypted twice using the two different keys. In other words, a segment shared by more than a title should be decrypted as many times as the number of the titles sharing the segment, which degrades the decoding performance of reproducing apparatuses significantly.
  • content data of titles sharing the same data segment should be encrypted with the same key, which means all the titles shown in FIG. 1 should be encrypted with the same key because Title #1 and Title #2 share a data segment and Title #2 and Title #3 share a data segment. If it is not allowed to encrypt different titles with different keys in high-capacity recording media, the effectiveness of copy protection is seriously deteriorated.
  • FIG. 2 is a block diagram of an apparatus for manufacturing read-only optical disks having encryption information in accordance with the present invention.
  • the apparatus comprises a laser diode 10 for generating a laser beam, a collimator 11 for collimating the generated laser beam, an optical modulator 13 for passing or blocking the parallel beam from the collimator 11 depending on the level of a modulated input signal (e.g., EFM signal) , a condensing lens 14 for concentrating the beam from the optical modulator 13 on a photosensitive layer (e.g., photo resist) located on a glass substrate, an encoder 20 for encoding input content data in a predefined format (e.g., the MPEG format) , a formatter 21 for encrypting the encoded data with a key selected from a key table 30a and for formatting the encrypted data into ECC block data suitable for recording, a high-capacity storage medium 23 (e.g., hard disk drive) for storing data, a disk reading/writing unit 22 for reading/
  • the recording controller 30 appends data required for mapping the data stored in the storage medium 23 to the read-only disk (e.g., key information and index information for key indexing) to the navigation information.
  • the data stored in the storage medium 23 is read under the control of the recording controller 30 and then modulated into a binary signal by the signal modulator 31.
  • the optical modulator 13 passes or blocks the collimated laser beam depending on the level of the modulated signal, thereby forming a pit train corresponding to the modulated signal on the photosensitive layer located on the glass substrate.
  • the condensing lens 14 moves outward slowly during the pit-forming process, thereby making the pit train be a spiral pattern.
  • the pit train represents data corresponding to the content data and navigation data therefor stored in the storage medium 23.
  • a stamper is made using the photosensitive layer having the pit train thereon and read-only disks storing the content data encrypted according to the present invention and navigation data including encryption information are manufactured using the stamper.
  • the encrypted content data and navigation data including encryption information (i.e., encryption key information and index information for key indexing) stored in the storage medium 23 are directly mapped to the read-only disk, the data structure of the storage medium 23 is the same as the data structure of the read-only disk. Therefore, only the method of writing data to the storage medium 23 according to the present invention will now be described because the method also applies to the read-only disk.
  • encryption information i.e., encryption key information and index information for key indexing
  • the recording method according to the present invention also applies to rewritable disks (e.g., Blu-ray Disk Rewritable) in that the content data encrypted according to the present invention and navigation data including encryption information can also be recorded on a rewritable optical disk instead of the storage medium 23.
  • the recording controller 30 controls a servo control unit for moving optical recording means (e.g., optical pickup) to a position at which data will be recorded.
  • An input video signal is encoded in a particular format (e.g., the MPEG format) by the encoder 20 and converted into ECC blocks by the formatter 21 and then written to the storage medium 23 by the reading/writing unit 22.
  • a data stream 101 pre-encoded by another apparatus may be provided from another storage medium.
  • the encoder 20 encodes input content data into GOPs each of which comprises a leading I-picture and possibly more pictures.
  • the recording controller 30 organizes one or more successive GOPs into a navigation unit such that the playback time duration thereof is between 0.4 and 1 second and creates navigation information for the navigation unit.
  • Information necessary for the creation of the navigation units is provided by the encoder 20.
  • One content is written as one or more clip files and video title set information (VTSI) , which is management information for the recorded data, is created and written as a single file (e.g., Video_TS.ifo) .
  • VTSI video title set information
  • the information required for creating the VTSI may be received from a user through a graphical user interface based menu preprogrammed in the recording controller 30.
  • management information including navigation data for the recorded content (e.g., index table, movie object, movie playlist, playitem, etc) is not the concern of the invention and thus will not be described here.
  • the recording and reproduction methods in accordance with the invention will now be described in detail with an emphasis on encryption information required for encrypting each title with one key or a combination of keys.
  • the formatter 21 encrypts the content data encoded by the encoder 20 or provided from another storage medium 101 with encryption keys selected from the encryption key table 30a and converts the encrypted data into ECC block data suitable' for recording.
  • the ECC formatted encrypted data is written to the storage medium 23 by the disk reading/writing unit 22.
  • the recording controller 30 selects an encryption key from the encryption key table 30a and provides the formatter 21 with the selected encryption key so that the formatter 21 can use the encryption key for encrypting data.
  • the predetermined data boundaries which are designated by data titles, data segments included in each title, or playitems, are stored in the recording controller 30.
  • FIG. 3 shows an exemplary content recorded by applying a different encryption key to each of the data segments specified by the predetermined boundaries in accordance with one embodiment of the invention.
  • Each of the data segments is referred to as a content protection system (CPS) unit.
  • CPS content protection system
  • FIG. 3 if there is a data segment shared by different titles (each title corresponding to logical continuous playback unit information) in a clip file, different encryption keys are applied to data divided by the boundaries of the shared data section.
  • the data of Clip File #1 has a data segment 3O 1 shared by two different titles, which divides the data into three data blocks.
  • the three data blocks, Block #1, Block #2, and Block #3 are encrypted using different keys, key 1, key 2, and key 3, respectively.
  • the data of Clip File #2 comprises three data blocks encrypted using three different encryption keys, key 4, key 5, and key 6.
  • AACS advanced access content system
  • the encryption keys applied to AACS key sequences as shown in FIG. 3 are stored in a key file.
  • the key file has a structure as shown in FIG. 4.
  • Content protection system (CPS) unit numbers as key index information are placed in the former part of the key file and used keys are placed in the latter part thereof.
  • the recording controller 30 creates an information field AACS_Key__Index_Info() to store information on keys used for encrypting data contained in a clip file in the associated clip information file (*.clpi) and writes key index information 403 for allowing access to the encryption key applied to each sequence in the information field AACS_Key_Index_Info() .
  • the AACS_Key_Index_Info () field contains the number of AACS key sequences included in the associated clip file 401 and the start position of each sequence 402. In the example shown in FIG. 3, the values to be written in the sequence start position 402 of Clip File #1 are 0, a, and b.
  • the key index information 403 contains information that points to CPS_Unit_number for Key_Index #i entries of the key file shown in FIG. 4, each of the entries storing the number of the CPS unit pointing to the position at which the associated encryption key is stored.
  • a recording apparatus therefore, can access a plurality of encryption keys used for encrypting data of a single clip file.
  • Title #1 is encrypted with key 1
  • key 2 is encrypted with key 3
  • Title #2 is encrypted with key 4, key 5, and key 6.
  • Title #3 is encrypted with key 2 and key 5.
  • FIG. 5 shows an exemplary content recorded by applying a different encryption key to each CPS unit in accordance with another embodiment of the invention, wherein each data section corresponding to a playitem is organized as one CPS unit.
  • the data section CPS_U #2 which is referenced by playitem 3I 2 of Title #1 and includes data section 3Oi shared by different playitems, is encrypted with a single key, key 2
  • the data section CPS_U #3 which is referenced by playitem 32i of Title #2 and includes data section 3O 2 shared by different playitems, is encrypted with a single key, key 3.
  • key 2 and key 3 are also stored in the key file for two playitems 33 ⁇ and 33 2 included in Title #3.
  • FIG. ⁇ a shows the structure of an exemplary embodiment of the key file for allowing reproducing apparatuses to access the encryption keys.
  • keys used for encrypting data of any titles are written in a key storage field 601 and index information for allowing access to keys used for encrypting data of a title is created for each of playitems belonging to the title and stored in the field 602.
  • index information for allowing access to keys used for encrypting data of a title is created for each of playitems belonging to the title and stored in the field 602.
  • key 1, key 2, and key 3 are written in the key storage field 601.
  • Title #1 contains two playitems and thus is associated with two index information fields,
  • CPS_Unit_number for Playitem[k] which respectively store CPS unit numbers 1 and 2.
  • Title #2 is associated with only one index information field which stores CPS unit number 3.
  • the index information fields, CPS_Unit_number for Playitem[k] associated with Title #3 store CPS unit numbers 2 and 3.
  • the key file structure shown in FIG. 6a also includes address information
  • Start_address_of_CPS_Unit_Info_for_Title [i] ) which points to the start address of information on CPS units in each title.
  • the address information is intended for allowing reproduction apparatuses to rapidly access information on the start addresses of CPS units.
  • the exemplary embodiment shown in FIG. 6b stores an encryption key used for encrypting data referenced by each playitem separately for the playitem 611.
  • the titles recorded on a recording medium can be encrypted using different encryption keys.
  • Title #1 is encrypted with key 1 and key 2
  • Title #2 is encrypted with key 3
  • Title #3 is encrypted with key 2 and key 3.
  • FIG. 7 shows an exemplary content recorded by applying a different encryption key to each CPS unit in accordance with yet another embodiment of the invention, wherein each clip file is treated as one CPS unit.
  • each clip file is encrypted using a different encryption key.
  • the playitems of Title #3 references data sections included in the two clip files and thus the keys used for encrypting the referenced data sections (i.e., key 1 and key 2) are stored in the key file.
  • FIG. 8a shows the structure of an exemplary key file for allowing reproducing apparatuses to access the encryption keys.
  • keys used for encrypting data of any titles are written in a key storage field 801 and index information for allowing access to keys used for encrypting data of a title (CPS_Unit__number for a Cliptk]) is created for each clip file belonging to the title.
  • key 1 and key 3 are written in the key storage field 801.
  • the value of the CPS_Unit_number for Clip [k] field for Title #1 is written to 1 and the value of the CPS_Unit_number for Clip [k] field for Title #2 is written to 2.
  • the value of the Num_of_Clips_in_Title [i] field for Title #3 is written to 2 and the values of the CPS_Unit_number for Clip [k] field for Title #3 are written to 1 and 2.
  • the exemplary embodiment shown in FIG. 8b stores an encryption key used for encrypting data of a clip file in the field 811 separately for the clip file.
  • FIG. 8c shows yet another embodiment of the key file which stores encryption keys used for each clip file.
  • information for identifying each clip file e.g., the clip file name and the CPS number of the clip file
  • the used encryption keys are collectively written in the latter part.
  • the titles recorded on a recording medium can be encrypted using different encryption keys.
  • Title #1 is encrypted with key 1
  • Title #2 is encrypted with key 2
  • Title #3 is encrypted with key 1 and key 2.
  • the recording controller 30 may encrypt the encryption keys with a mater key after recording all the encryption keys on the recording medium 23.
  • Encrypted data and information on the keys used for encrypting the data are recorded on a recording medium or a recording medium storing encrypted data and information on the keys used for encrypting the data is manufactured by the aforementioned procedure.
  • FIG. 9 shows a block diagram of an apparatus for reproducing a recording medium 71 storing encrypted content data and encryption information in accordance with the present invention.
  • a reproducing controller 70 receives a reproduction request, a reproducing controller 70 first reads management information including navigation data through an optical pickup 72 by controlling a driver 73 and stores the management information in a memory 79
  • the management information includes an encryption key file having a structure as shown in FIGS. 4, 6a, 6b, 8a, 8b, or 8c.
  • the request for reproduction is made through a user interface (buttons on the reproduction apparatus, remote controller, etc) and user input can be entered through a graphical user interface based menu preprogrammed in the recording controller 30.
  • a deformatter 74 performs error correction operations on the reproduced data. Error corrected data is applied to a demultiplexer 75 if it contains A/V data. The error corrected data which is not A/V data (e.g., encryption information, navigation data, etc) is applied to the reproducing controller 70. If the encryption keys stored in the key file is encrypted, the reproducing controller 70 decrypts the encrypted encryption key with a registered content provider's private key, which was obtained from the content provider and stored in an internal memory.
  • A/V data e.g., encryption information, navigation data, etc
  • the reproducing controller 70 reads data segments of clip files corresponding to a title or titles specified by the reproduction request through the optical pickup 72 by controlling the driver 73.
  • the demultiplexer 75 demultiplexes input data stream into encoded video and audio data.
  • the A/V decoder 76 decrypts the encrypted data using encryption keys obtained by a method to be described later and decodes the decrypted A/V data to retrieve original video and audio signals.
  • the operation of the deformatter 74, demultiplexer 75, and A/V decoder 76 is supervised by the reproducing controller 70.
  • the reproducing controller 70 acquires an encryption key associated with the next CPS unit from the memory 79 and provides the A/V decoder 76 with the encryption key.
  • a key file and clip information files (*.clip) as shown in FIG. 4 are loaded to the memory 79.
  • the reproducing controller 70 acquires key index information (key_index[i] ) which corresponds to the number of the AACS key sequence that begins to be inputted to the A/V decoder 76 from the clip information file and reads an encryption key (Encrypted Unit Key for CPS Unit #k) pointed to by the index information before providing the A/V decoder 76 with the encryption key.
  • each of data sections referenced by playitems is organized as a CPS unit and a key file as shown in FIG. 6a or FIG. 6b is provided and loaded in the memory 79.
  • the reproducing controller 70 reads all the encryption keys from the key file loaded in the memory 79 and provides the A/V decoder 76 with the encryption keys sequentially such that each CPS unit can be decrypted with an encryption key that was used to encrypt the CPS unit.
  • each clip file is organized as a CPS unit and a key file as shown in FIG. 8a, FIG. 8b, or FIG. 8c is provided and loaded in the memory 79.
  • the reproducing controller 70 reads all the encryption keys from the key file loaded in the memory 79 and provides the A/V decoder 76 with the encryption keys sequentially such that each CPS unit can be decrypted with an encryption key that was used to encrypt the CPS unit.
  • the file name of a clip file included in a title the reproduction of which is requested is first identified and the encryption key for the title is acquired through the CPS unit number which pairs with the file name.
  • the encryption information as shown in FIGS. 4, 6a, 6b, 8a, 8b, or 8c is recorded on a recording medium.
  • the present invention efficiently protects the copyright of content data recorded on a high-capacity recording medium by allowing different titles recorded on a recording medium to be encrypted with different encryption keys even in the case where some data sections are shared by more than one title.
  • an encryption key used for encrypting data of a title is revealed by some malicious methods, the data of other titles can be copy protected as long as the data is encrypted with other encryption keys.

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  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Signal Processing (AREA)
  • Storage Device Security (AREA)
  • Signal Processing For Digital Recording And Reproducing (AREA)

Abstract

Des données de chiffrement de contenu relatives à des données de contenu sont enregistrées sur un support d'enregistrement. Une pluralité de clés de chiffrement sont utilisées pour chiffrer ou déchiffrer une pluralité de fichiers séquences contenant des données de contenu, de sorte que chacune des clés de chiffrement sert à chiffrer ou à déchiffrer tout ou partie des données de chacun de la pluralité des fichiers séquences. Le procédé de chiffrement de l'invention permet de chiffrer des titres différents devant être chiffrés à l'aide de clés de chiffrement différentes lorsque certains segments de données sont partagés par de multiples titres.
EP05823731A 2004-12-13 2005-12-06 Procede et dispositif pour ecrire et utiliser des cles servant a chiffrer/dechiffrer du contenu, et support d'enregistrement stockant les cles ecrites a l'aide du procede Ceased EP1825470A4 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US63499804P 2004-12-13 2004-12-13
US63833204P 2004-12-23 2004-12-23
KR1020050105754A KR20060066627A (ko) 2004-12-13 2005-11-05 컨텐트의 암호/해독을 위한 키를 기록하고 사용하는 방법및 장치와 그 방법에 의해 키가 기록되어 있는 기록매체
PCT/KR2005/004146 WO2006065034A1 (fr) 2004-12-13 2005-12-06 Procede et dispositif pour ecrire et utiliser des cles servant a chiffrer/dechiffrer du contenu, et support d'enregistrement stockant les cles ecrites a l'aide du procede

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