Classifications

• • 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
  • G11B20/00094—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving measures which result in a restriction to authorised record carriers
  • G11B20/00123—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving measures which result in a restriction to authorised record carriers the record carrier being identified by recognising some of its unique characteristics, e.g. a unique defect pattern serving as a physical signature of 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
• • 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
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
  • H04L9/32—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials
  • H04L9/3236—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials using cryptographic hash functions
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L2209/00—Additional information or applications relating to cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
  • H04L2209/60—Digital content management, e.g. content distribution

Definitions

• the present invention relates to a method for securing content on a read-only recording medium and a recording medium storing content secured by the method.
• 2.BACKGROUNDART DVD-ROM called as DVD, provides a recording capacity of about 4.7 GBytes and therefore can store content such as movie with quality much better than that of TV signal; DVD is now being widely used.
• the present invention is directed to provide a method for securing content by providing information to confirm authorization of content on a recording medium, thereby preventing unauthorized reproduction much more effectively.
• Another objective of the present invention is to provide a method for securing content, the method enabling prompt validation for reproduction of provided content.
• Another objective of the present invention is to provide a recording medium storing content, the data of which have been processed by a method for securing content, the method preventing unauthorized reproduction of content much more effectively and enabling prompt validation for reproduction.
• a recording medium includes content data recorded after encryption and a resultant value obtained by applying a hash function to the encrypted content data.
• a method for recording data on a recording medium is characterized in that input content data are encrypted and recorded on a recording medium; and a resultant value is recorded on the recording medium, the resultant value being obtained by applying a hash function to the content data recorded after encryption.
• a method for reproducing a recording medium is characterized in that a hash function is applied to content data recorded after encryption and validity of the recorded content data is determined according to a comparison result obtained by comparing a resultant value obtained by the above application with a hash result value recorded on the recording medium.
• a hash function is reapplied to a list of function values obtained by applying a hash function to each block unit dividing the content data recorded after encryption, the resultant value of which is used as a hash result value for determining said validity.
• a list of function values obtained by applying a hash function to each block unit dividing the content data recorded after encryption is used as a hash result value for determining said validity.
• data with electronic signature using public key of a content provider is added to a resultant value obtained by reapplying a hash function to the list of function values.
• decryption key for the content data is obtained from the recording medium or through network; the recorded content data are decoded by the obtained decryption key and decoded output is produced.
• Fig. 1 illustrates, according to the present invention, the structure of a disc manufacturing apparatus for producing read-only recording media having information to check the validity of content data
• Fig. 2 illustrates data processing operations to secure recorded content according to one embodiment of the present invention
• Fig. 3 illustrates the structure of one embodiment of an apparatus reproducing a read-only recording medium storing data-secured content according to the present invention.
• Fig. 1 illustrates the structure of an apparatus according to the present invention, the apparatus being for manufacturing read-only optical discs having information for checking validity, comprising: a laser diode 10 which generates laser beam; a collimator 11 which collimates the generated laser beam as a parallel beam,- an optical modulator 13 which blocks or transmits the parallel beam according to input modulated signal, for example, according to the level of EFM signal; a condensing lens 14 which concentrates output light of the optical modulator 13 onto the surface of a sensitive layer such as photo resist on a glass negative; an encoder 20 which encodes input content data , for example, according to MPEG format; a formatter 21 which encrypts the encoded data according to given key value and configures the encrypted data in terms of ECC (Error Correction Code) block format for recording; a high capacity storing medium 23 such as hard disk drive (HDD) which stores data; a disk reading/writing unit 22 which records on and reads out from the storing medium 23; a signal modulator 31 which modul
• the data controller 30 carries out data processing operations for securing content, which are to be described later, upon the data stored in the above way.
• the data, where the processing operations have been applied, are read by control of the data controller 30 and modulated into binarized signal by the signal modulator 31; the modulated signal blocks or transmits output light of the optical modulator 13 according to the level thereof and forms pit trains at the sensitive layer on the glass negative according to the binarized signal.
• pit trains While pit trains are being formed, the condensing lens 14 gradually moves to outer circumference by the control of the data controller 30, thereby forming pit trains on the sensitive layer along spiral tracks.
• These pit trains are the data corresponding to content data and navigation data stored in the storingmedium 23 ; a stamper is manufacturedbyusing a sensitive layer wherein the pit trains are formed and read-only discs having navigation data according to the present invention are manufactured by using the stamper.
• input video signal is converted to a data stream being encoded in a particular format, for example, MPEG format by the encoder 20, configured in terms of ECC block by the formatter 21 and recorded on the storing medium 23 by the reading/writing unit 22.
• a data stream encoded in advance by a different apparatus can also be provided through another storing medium 101.
• GOP is created, which is a set of pictures having I-picture as the head.
• the data controller 30 configures one or multiple GOPs having presentation time length of 0.4 - 1 second into a single navigation unit and generates navigation information for the unit . Necessary information for configuring by the navigation unit is received from the encoder 20.
• video title set information VTSI
• VTSI video title set information
• necessary information for generating VTSI can be provided by the user through a menu based on GUI (Graphical User Interface) pre-programmed by the data controller 30. Since generation of management information including navigation data for recorded content does not have direct relevancy to the present invention, a further detailed explanation will be omitted.
• the formatter 21 encrypts encoded data based on encryption key 30a approved by the data controller 30 and configures the encrypted data to ECC blocks for recording, thereby making the ECC blocks being recorded on the storingmedium 23 through the reading/writing unit 22.
• the encryption key used for the encryption procedure is one of commonly known methods and recorded or formed at a particular position of a read-only recording medium through the storingmedium23 or directly from stampermanufacturing procedure.
• the data controller 30 carries out data processing operations for securing content data encrypted and recorded in a way described above.
• Fig. 2 illustrates data processing operations for securing recorded content according to one embodiment of the present invention.
• the data controller 30 divides content data recorded after encryption 200 by block units of a fixed size, carries out hashing in order by sequentially reading each block through the reading/writing unit 22, generates a hash table 201, and records again the hash table on the storing medium 23 through the reading/writing unit 22.
• a hash result 201a (hereinafter, it is also referred to as "content digest') is obtained by feeding encrypted data within the block into a hash function 30b previously assigned S201.
• hash table 201 is obtained.
• a hash table 201 Once a hash table 201 is obtained, necessary information for managing the table such as number of content digests, size of each digest (or position of each digest in the table) is created and recorded as header information 201b of the table. After a hash table 201 is obtained, necessary information for managing the table such as number of content digests, size of each digest (or position of each digest in the table) is created and recorded as header information 201b of the table.
• a hash result 202a (hereinafter, it is also referred to as 'hash table digest') is obtained by applying a pre-assigned hash function 30b (at this time,
• the content certificate 202 completed in the above manner is recorded in the form of a file at a specified position within the storing medium 23 or with a specified name through the reading/writing unit 22; thus, data
• FIG. 3 illustrates the structure of one embodiment of an apparatus reproducing a read-only recording medium 71 storing content where a process for securing data has been applied according to the present invention.
• a reproducing controller 70 controls a drive 73 so that an optical pickup 72 first reads out a content certificate under the data structure as shown in Fig. 2.
• the playback request is realized by a user interface (operation buttons of a playback apparatus or remote control associated with the apparatus) .
• User input can be specified, for example, through a menu based on GUI (Graphical User Interface) pre-programmed in the reproducing controller 70.
• GUI Graphic User Interface
• Error correction is applied to read-out data by a deformatter 74; A/V data is fed into a demultiplexer 75 and data other than A/V data (hash table data, navigation data and so on) are fed into the reproducing controller 70.
• the reproducing controller 70 by using private keys of content providers 70a supplied by the content providers and pre-registered on internal memory, interprets the read-out content certificate. During this procedure, a player, having been manufactured illegally and thus, not having registered private keys of content providers, cannot interpret a content certificate stored on a loaded read-only medium.
• the reproducing controller 70 obtains a content hash table for stored content data 200 by hashing using a pre-stored hash function 70b and applies hashing again to the content hash table 201, thereby obtaining a content certificate and subsequently comparingwith the content certificate interpreted previously. If the hash function 70b stored previously in the reproducing controller 70 were the same as a hash function with which a content provider had applied hashing to content, exactly the same certificate would be obtained. If various content providers used a couple of separate hash functions, the reproducing controller 70 would accordinglyprepare multiple hash functions.
• the reproducing controller 70 controls the drive 73 so that the optical pickup 72 reads out content data.
• the demultiplexer 75 reversely multiplexes an input data stream into encoded video/audio data; the A/V decoder 76 interprets input data encrypted data by using decryption key provided by the reproducing controller 70 and generates the original video/audio signal by decoding the decrypted A/V data.
• operations of the deformatter 74, the demultiplexer 75, and the A/V decoder 76 are controlled by the reproducing controller 70.
• the decryption key is obtained by the recording medium 71 through one of commonly known methods. Alternatively, the decryption key can be received through a network from an external server associated with the content stored in the recording medium 71.
• a content hash table is obtainedbyhashing content having encrypted data, whereas hashing for the hash table may not be carried out.
• a content hash table 201 can provided being recorded along with content on a recording medium.
• the apparatus of Fig.3, by a first hashing of content can determine the validity of content stored in a loaded recording medium.
• an apparatus for reproducing a recording medium storing the content can easily check the validity of the stored content by carrying out hashing operations only. In other words, validation of content can be realized independently of decryption procedure of content data.
• an apparatus for reproducing a recording medium storing content in order to check the validity of the content, must first decrypt content data and compare the hashing result obtained by hashing of the decrypted data with a hash table or content certificate in the recording medium. Compared with the method described previously, it takes more time before actual reproduction of valid content is achieved. In addition, considering the fact that decryption procedure for encrypted data is typically carried out at A/V decoding stage, it is not desirable in terms of load since communications traffic between A/V decoder and reproducing controller takes place even for checking validity only.
• the method is more advantageous in the aspects of validation time and effective use of resources.
• the present invention described with limited embodiments above enables reproductionof authorized content (validity checked content) only by carrying out hashing for securing content stored in a read-only recording medium; furthermore, decision about authorization of content, namely, validation is carried out independently of encryption, whereby reproduction or denial of reproduction is made quickly. Therefore, user convenience and function for protecting copyright of a content provider are enhanced.

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

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• 2005
  • 2005-12-13 WO PCT/KR2005/004256 patent/WO2006065050A1/en active Application Filing
  • 2005-12-13 EP EP05819089A patent/EP1825468A4/de not_active Withdrawn

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