EP1218884A2 - Protection contre la reproduction illicite de contenus - Google Patents

Protection contre la reproduction illicite de contenus

Info

Publication number
EP1218884A2
EP1218884A2 EP01949061A EP01949061A EP1218884A2 EP 1218884 A2 EP1218884 A2 EP 1218884A2 EP 01949061 A EP01949061 A EP 01949061A EP 01949061 A EP01949061 A EP 01949061A EP 1218884 A2 EP1218884 A2 EP 1218884A2
Authority
EP
European Patent Office
Prior art keywords
section
sections
data set
data
entirety
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.)
Withdrawn
Application number
EP01949061A
Other languages
German (de)
English (en)
Inventor
Antonius A. M. Staring
Michael A. Epstein
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.)
Koninklijke Philips NV
Original Assignee
Koninklijke Philips Electronics NV
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 US09/537,079 external-priority patent/US6865676B1/en
Application filed by Koninklijke Philips Electronics NV filed Critical Koninklijke Philips Electronics NV
Publication of EP1218884A2 publication Critical patent/EP1218884A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T1/00—General purpose image data processing
    • G06T1/0021—Image watermarking
    • G06T1/005—Robust watermarking, e.g. average attack or collusion attack resistant
    • G06T1/0071—Robust watermarking, e.g. average attack or collusion attack resistant using multiple or alternating watermarks
    • 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
    • G11B20/00166—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving measures which result in a restriction to authorised contents recorded on or reproduced from a record carrier, e.g. music or software
    • 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
    • G11B20/00681—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving measures which prevent a specific kind of data access
    • G11B20/00695—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving measures which prevent a specific kind of data access said measures preventing that data are read from the recording medium
    • 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
    • G11B20/00884—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving a watermark, i.e. a barely perceptible transformation of the original data which can nevertheless be recognised by an algorithm
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2201/00—General purpose image data processing
    • G06T2201/005—Image watermarking
    • G06T2201/0064—Image watermarking for copy protection or copy management, e.g. CGMS, copy only once, one-time copy

Definitions

  • This invention relates primarily to the field of consumer electronics, and in particular to the protection of copy-protected content material.
  • the illicit distribution of copyright material deprives the holder of the copyright legitimate royalties for this material, and could provide the supplier of this illicitly distributed material with gains that encourage continued illicit distributions.
  • content material that is intended to be copy-protected such as artistic renderings or other material having limited distribution rights, are susceptible to wide-scale illicit distribution.
  • the MP3 format for storing and transmitting compressed audio files has made the wide-scale distribution of audio recordings feasible, because a 30 or 40 megabyte digital audio recording of a song can be compressed into a 3 or 4 megabyte MP3 file. Using a typical 56 kbps dial-up connection to the Internet, this MP3 file can be downloaded to a user's computer in a few minutes.
  • a malicious party could read songs from an original and legitimate CD, encode the songs into MP3 format, and place the MP3 encoded song on the Internet for wide-scale illegitimate distribution.
  • the malicious party could provide a direct dial-in service for downloading the MP3 encoded song.
  • the illicit copy of the MP3 encoded song can be subsequently rendered by software or hardware devices, or can be decompressed and stored onto a recordable CD for playback on a conventional CD player.
  • a number of protection schemes including those of the SDMI, have taken advantage of this characteristic of lossy reproduction to distinguish legitimate material from illegitimate material, based on the presence or absence of an appropriate watermark.
  • two types of watermarks are defined: "robust" watermarks, and "fragile” watermarks.
  • a robust watermark is one that is expected to survive a lossy reproduction that is designed to retain a substantial portion of the original content material, such as an MP3 encoding of an audio recording.
  • a fragile watermark is one that is expected to be corrupted by a lossy reproduction or other illicit tampering.
  • the presence of a robust watermark indicates that the content material is copy protected, and the absence or corruption of a corresponding fragile watermark when a robust watermark is present indicates that the copy protected material has been tampered with in some manner.
  • An SDMI compliant device is configured to refuse to render watermarked material with a corrupted watermark, or with a detected robust watermark but an absent fragile watermark, except if the corruption or absence of the watermark is justified by an "SDMI-certified" process, such as an SDMI compression of copy protected material for use on a portable player.
  • an "SDMI-certified" process such as an SDMI compression of copy protected material for use on a portable player.
  • the term "render” is used herein to include any processing or transferring of the content material, such as playing, recording, converting, validating, storing, loading, and the like.
  • This scheme serves to limit the distribution of content material via MP3 or other compression techniques, but does not affect the distribution of counterfeit unaltered (uncompressed) reproductions of content material. This limited protection is deemed commercially viable, because the cost and inconvenience of downloading an extremely large file to obtain a song will tend to discourage the theft of uncompressed content material.
  • the invention provides a method for discovering a theft, a method of decoding, a storage medium, an encoder and decoder as defined in the independent claims.
  • Advantageous embodiments are defined in the independent claims.
  • Each data item comprises one or more sections, the totality of all sections comprising the complete data set.
  • Each section of the data set is linked to another section of the data set, and each section's link is bound to the section via the use of one or more watermarks.
  • the link between sections is formed by a random selection of each linked-to section.
  • each link contains an identifier of the linked-to section that can be used to determine that a retrieval of a linked-to section corresponds to the originally assigned linked-to section. If the identifier associated with the linked-to section does not properly match the presented linked-to section, a rendering of the data items of the data set is prevented.
  • a closed linked list is formed, so that every section of the data set can be included in the verification process, if desired.
  • FIG. 1 illustrates an example system for protecting copy-protected content material in accordance with this invention
  • FIG. 2 illustrates an example data structure that facilitates a determination of the presence of an entirety of a data set in accordance with this invention
  • FIG. 3 illustrates an example alternative data structure that facilitates a determination of the presence of an entirety of a data set, and a verification of sections in the data set, in accordance with this invention.
  • FIG. 4 illustrates an example alternative data structure that facilitates a determination, based on a statistical degree of certainty, that the entirety of the data set is present, in accordance with this invention.
  • the invention is presented herein in the context of digitally recorded songs. As will be evident to one of ordinary skill in the art, the invention is applicable to any recorded information that is expected to be transmitted via a limited bandwidth communications path.
  • the individual content material items may be data records in a larger database, rather than songs of an album.
  • This copending application teaches a binding of the data items in the data set by creating a watermark that contains a data-set-entirety parameter and embedding this watermark into each section of each data item.
  • the copending application also teaches including a section-specific parameter (a random number assigned to each section) in the watermark.
  • the referenced copending application teaches the use of "out of band data" to contain the entirety parameter, or information that can be used to determine the entirety parameter.
  • the section watermarks are compared to this entirety parameter to assure that they are the same sections that were used to create the data set and this entirety parameter.
  • the entirety parameter is based on a hash of a composite of section-specific identifiers.
  • the referenced copending application also teaches the use of digitally signed certificates and other techniques that rely on cryptographic techniques, such as hashing and the like.
  • a self-referential data set is used that facilitates the determination of whether the entirety of the data set is present, without the use of out of band data and without the use of cryptographic functions, such as a hash function. If the entirety of the data set is not present, subsequent processing of the data items of the data set is terminated.
  • a compliant playback or recording device is configured to refuse to render an individual song in the absence of the entire contents of the CD.
  • the time required to download an entire album on a CD in uncompressed digital form, even at DSL and cable modem speeds, can be expected to be greater than an hour, depending upon network loading and other factors.
  • the likelihood of a theft of a song via a wide-scale distribution on the Internet is substantially reduced.
  • FIG. 1 illustrates an example block diagram of a protection system 100 in accordance with this invention.
  • the protection system 100 comprises an encoder 110 that encodes content material onto a medium 130, and a decoder 120 that renders the content material from the medium 130.
  • the encoder 110 includes a selector 112 that selects content material from a source SRC, a binder 116 that builds an entirety verification structure, and a recorder 114 that records the content material onto the medium 130.
  • the selector 112 may be configured to select content material corresponding to songs that are being compiled into an album. For ease of reference, each selected content material item is termed a "data item", and the entirety of the data items forms a "data set".
  • Each data item comprises one or more sections of data that form the data item, the totality of sections also forming the "data set".
  • the binder 116 creates a data structure consisting of links between sections of the data set, by means of which the entirety of the data set can be verified. Preferably, each section's link is bound to the section via the use of one or more watermarks.
  • the recorder 114 appropriately formats, encodes, and stores the data set, with the aforementioned data structure, on the medium 130, using techniques common in the art.
  • the selector 112 selects data items to be added to the data set until the size of the data set is deemed large enough to discourage a subsequent transmission of the data set via a limited bandwidth communications channel.
  • This "discouraging size" is a subjective value, and will depend upon the assumed available communications bandwidth, the loss incurred by the transmission, and so on. Other criteria may also be used to determine whether to add additional data items to the data set. For example, if the data items correspond to songs of an existing album collection, all of the songs will typically be added to the data set, regardless of whether the size of the data set has exceeded the determined discouraging size.
  • data items comprising random data bits may be added to the data set to increase its size. These random bits will typically be stored as out of band data, CD-ROM data, and the like, to prevent it from being rendered as audible sounds by a conventional CD player.
  • the data items may comprise other sample songs that are provided to encourage the sale of other albums, or images and video sections related to the recorded content material.
  • promotional material such as Internet access subscription programs may also be included in the recorded information on the recorded medium.
  • the decoder 120 in accordance with this invention comprises a renderer 122 and a gate 124 that is controlled by an entirety checker 126.
  • the renderer 122 is configured to retrieve information from a medium reading device, such as a CD reader 132.
  • the renderer 122 retrieves the information by specifying a location index, and in response, the reader 132 provides the data located at the specified location index on the medium 130.
  • Block reads of data at contiguous locations on the medium 130 are effected by specifying a location index and a block size.
  • the dotted lines of FIG. 1 illustrate an example song extractor 142 that extracts a song from the medium 130 and communicates it to an example CD imitator 144, representative of a possible illicit download of the song via the Internet.
  • the CD imitator 144 represents, for example, a software program that provides information in response to a conventional CD-read command. Alternatively, the information received from the song extractor can be written to a CD medium, and provided to the conventional CD reader 132.
  • the song extractor 142 is likely to be used because the transmission of the entirety of the contents of the medium 130 is assumed to be discouraged by the purposefully large size of the contents of the medium 130.
  • the entirety checker 126 is configured to obtain data from the medium 130, typically via the renderer 122, to determine whether the entire data set is present.
  • FIG. 2 illustrates an example data structure 200 for storing data items in a data set that facilitates a determination of whether the entirety of the original data set is present.
  • a track T 210 and section S 220 structure is illustrated, consistent with the memory structure of conventional CD and other storage media. As illustrated, each track T 210 may have a different number of sections S 220.
  • each section S 220 contains a link 230 to another section S in the data structure 200. In a preferred embodiment, the link 230 of each section 220 is based on a random selection of available other links.
  • Section S(0,0) 220a has an associated link La 230a that "links to" section S(l,l) at Track Tl, Section S(l,l) 220f.
  • This section 220f has an associated link Lf 230f that links to section (m,0) at Track Tm.
  • the links form a closed linked list, such that a traversal through the data set from link to link forms a closed loop.
  • the first section that receives a random linked-to section (in this example, section S(0,0) 220a) is held in reserve as the random selection process progresses through the data set, via each linked-to section, and assigns a randomly selected available section to each linked-to section.
  • the first section is assigned as the last section's linked-to section.
  • the section S(l,nl) 220h in the example data structure 200 of FIG. 2 represents the last linked-to section of the data set 200, and its linked-to section Lh 23 Oh is the first section S(0,0) 220a, thereby forming a closed linked list of all of the sections 220 of the data set 200.
  • the entirety of the data set 200 is verified by progressing through the data set 200 via the links L 230 and verifying that each linked-to section is present.
  • the link L 230 of each section 220 is preferably encoded as a mix of robust and fragile watermarks, for example, the linked-to track number may be encoded as a robust watermark, and the linked-to section number within that track may be encoded as a fragile watermark.
  • a robust watermark is one whose removal causes substantial damage or corruption of the data in which it is embedded
  • a fragile watermark is one which incurs damage or corruption if the data in which it is embedded is modified or deleted, such as by compression.
  • FIG. 3 illustrates an example alternative data structure 300 that facilitates a further verification that the linked list, and each linked-to section, has not been modified or replaced.
  • a random number R(T,S) 332 is assigned to each section S 220 of each track T 210, as in the referenced copending application, and the random number of each section's linked-to section R(L) 336 is also assigned to each section S 220.
  • the assigned linked-to section's random number R(L) 336 is compared to the random number R(T,S) 332 at the linked-to section.
  • These random numbers are also encoded as a watermark that is embedded in the section 220.
  • these numbers are encoded as a fragile watermark, because a fragile watermark consumes less resources than a robust watermark, and a fragile watermark is sensitive to a modification, such as a compression, of the section data in which it is embedded.
  • a modification such as a compression
  • Other arrangements of robust and fragile watermarks will be evident to one of ordinary skill in the art in view of this invention.
  • other methods of creating the identifiers in each section can be used, such as putting a number in one section, and a function value of that number in its linked-to section.
  • Data items are accumulated to form a data set that is sufficient large so as to discourage a transmission of the data set via a limited bandwidth communications channel, such as a download from the Internet.
  • each section comprising the data item is assigned a random number that is used to identify the section, and its size is added to the accumulated size of the data set.
  • a random closed linked list of the sections of the data set is created, as discussed above.
  • One or more watermarks are created for each section, comprising the random number assigned to the section, the linked-to section, and the random number assigned to the linked-to section.
  • a combination of robust and fragile watermarks are preferably used for encoding the information associated with each section.
  • the section and its embedded watermark(s) are recorded onto the recording medium, such as a CD.
  • an embodiment is discussed of the rendering of data items of a data set in dependence upon the presence of the entirety of the data set, using the example data structure 300 of FIG. 3 to determine the presence of the entirety of the data set. It is assumed that the rendering device has detected the presence of copy-protected material, via for example, the detection of a watermark or other marking of the material.
  • a starting section S is selected, preferably at random.
  • the watermark of the starting section S is read.
  • the watermark includes a link address that specifies the track and section number of another section, and a random number that is associated with the section at the link address.
  • the watermark of the linked-to section is read. This watermark includes the random number assigned to the linked-to section, as well as its link address and associated random number.
  • the random number associated with the linked-to section that is contained in the start section is compared with the random number contained in the linked-to section. If the random numbers are not equal, subsequent processing of data items in the data set, such as the rendering of a song, is terminated.
  • other linked-identifier techniques may also be used, such as storing a random number in one section, and a function, such as a hash, of this number in the linked-to section. If an alternative encoding scheme is used, the comparison is modified accordingly.
  • the process continues, by advancing to the linked-to section.
  • the above section-identifier matching is continued for each subsequent linked-to section, until sufficient confidence is gained that the entirety of the data set is present.
  • absolute confidence can be gained by continuing until the linked-to section becomes the original start section, indicating that all links in the closed linked list have been processed.
  • the reading of each watermark is time consuming, and a substantial delay before the rendering of a song may be unacceptable to consumers.
  • the rendering of the song begins immediately after a few successful random number matches. Thereafter, if the rendering system is able to read information from the medium faster than is required for rendering the material, additional linked-to section watermarks are read and verified, and the rendering is terminated if and when a mis-match is found.
  • FIG. 4 illustrates an alternative data structure 600 that uses randomly linked pairs of sections to verify the presence of an entirety of the data set.
  • each section 620 has an associated linked-to section L 634 and an associated random number R 636.
  • the linked-to section 620' has a linked-to section L 634' that points back to the linked-from section 620. That is, the linked-to addresses L 634, 634' form a linked pair of sections 620, 620'.
  • a common random number R 636 is assigned to each section of the linked pair of sections 620, 620'.
  • the range, or approximate range, of the section addresses can be determined, so that the first "randomly selected section" is a viable section on the recorded medium.
  • the table of contents of the medium may be used to determine the viable track addresses, assuming that the table of contents has an embedded fragile watermark, or other security device, that can be used to determine the validity of the table of contents. If a range cannot be determined, the first randomly selected section will be from the track selected for rendering. In this manner, if a malicious party uses a song extractor 142 (FIG.
  • the selected song is used to generate the first section for verification
  • absolute certainty that all sections are present can be achieved by maintaining a list of tested sections, and verification continued until all section-pairs are tested.
  • This approach assumes that the range of the section addresses can be determined or estimated, so that a truncation of the data set can be detected.
  • the range of the section addresses can be assumed to be continuous through the range of link addresses in the selected song. For example, if one of the link addresses is track 10, section 9, a verification of each section 0 through 9 of track 10 can be made, and a verification of section 0 of tracks 0 through 10 can be made.
  • random section pairs are tested until sufficient confidence is gained to justify the determination, with substantial statistical certainty. That is, for example, if only half the data set is actually present, the random selection of the first section, from within the total range of all sections, is likely to detect an absence of this section 50% of the time; if this section is present, the likelihood of its linked- to section being present is 50%. Thus, a successful pair-test provides 75% confidence that at least half the data set is present. Each successive test increases either the confidence level or the expected proportion of the data set being present, or both.
  • Statistical tests are commonly available for determining an appropriate number of pair-test to achieve a desired level of confidence that a given proportion of the data set is present. In a typical embodiment, the verification of at least five randomly selected pairs is considered sufficient to determine the presence or absence of the entirety of the data set.
  • the watermark, or other parameter requires ten seconds of a recording for a reliable embedding, the remainder of ((the song's length) modulo (10 seconds)) will be recorded on the medium, but not included in the "data set" whose entirety is being checked.
  • some promotional material may be included on the recorded medium, but purposely excluded from the data set, so that it may be freely copied and rendered elsewhere.
  • the example flow diagrams are presented for ease of understanding, and the particular arrangement and sequence of steps are presented for illustration. For example, simple equalities are illustrated in the decision blocks for determining correspondence, whereas depending upon the particular techniques used to encode or decode the parameters, the assessment as to whether the read item corresponds to a determined item can include a variety of intermediate processes.

Abstract

Selon l'invention, on choisit (112) un nombre suffisant d'articles de données destinés à être inclus dans un fichier afin d'entraver la transmission de la totalité du fichier sur un chemin (130) de communication à largeur de bande limitée, telle que l'Internet. Chaque article de données comprend une ou plusieurs sections, qui, ensemble, constituent la totalité du fichier. Chacune des sections du fichier est reliée à une autre section du fichier, chaque liaison entre sections se faisant via l'utilisation d'un ou de plusieurs filigranes. A la présentation du matériel destiné à la restitution, on vérifie (126) la présence de la totalité du fichier par le contrôle de la présence des sections reliées. Pour plus de sécurité, les liaisons entre les sections sont établies sur la base d'une sélection aléatoire de chaque section reliée. Pour vérifier que chaque section reliée correspond à la section d'origine qui a été reliée, chaque liaison contient un identifiant de la section reliée, qui peut servir à déterminer la correspondance entre une section reliée récupérée et la section reliée originellement affectée. Si l'identifiant associé à la section reliée ne correspond pas à la section reliée présentée, le rendu des articles de données du fichier est empêché. Dans un mode de réalisation préféré, une liste liée fermée est formée, de manière que chaque section du fichier puisse, le cas échéant, être incluse dans le processus de vérification.
EP01949061A 2000-02-07 2001-02-05 Protection contre la reproduction illicite de contenus Withdrawn EP1218884A2 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US18083800P 2000-02-07 2000-02-07
US180838P 2000-02-07
US09/537,079 US6865676B1 (en) 2000-03-28 2000-03-28 Protecting content from illicit reproduction by proof of existence of a complete data set via a linked list
US537079 2000-03-28
PCT/EP2001/001207 WO2001057867A2 (fr) 2000-02-07 2001-02-05 Protection contre la reproduction illicite de contenus

Publications (1)

Publication Number Publication Date
EP1218884A2 true EP1218884A2 (fr) 2002-07-03

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP01949061A Withdrawn EP1218884A2 (fr) 2000-02-07 2001-02-05 Protection contre la reproduction illicite de contenus

Country Status (4)

Country Link
EP (1) EP1218884A2 (fr)
JP (1) JP2003521791A (fr)
CN (1) CN1214383C (fr)
WO (1) WO2001057867A2 (fr)

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IL145662A0 (en) * 2000-02-01 2002-06-30 Koninkl Philips Electronics Nv Protecting content from illicit reproduction by proof of existence of a complete data
US20030031317A1 (en) * 2001-08-13 2003-02-13 Michael Epstein Increasing the size of a data-set and watermarking
US7194617B2 (en) * 2001-11-05 2007-03-20 Koninklijke Philips Electronics N.V. Method and apparatus to prevent the unauthorized copying of digital information
US7636440B2 (en) * 2003-01-31 2009-12-22 Hewlett-Packard Development Company, L.P. Digital watermark with variable location
US7627552B2 (en) 2003-03-27 2009-12-01 Microsoft Corporation System and method for filtering and organizing items based on common elements
US7421438B2 (en) 2004-04-29 2008-09-02 Microsoft Corporation Metadata editing control
US7665028B2 (en) 2005-07-13 2010-02-16 Microsoft Corporation Rich drag drop user interface

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US5915027A (en) * 1996-11-05 1999-06-22 Nec Research Institute Digital watermarking
CN1153456C (zh) * 1998-03-04 2004-06-09 皇家菲利浦电子有限公司 水印检测的方法和设备
GB2364513B (en) * 1998-12-23 2003-04-09 Kent Ridge Digital Labs Method and apparatus for protecting the legitimacy of an article

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Also Published As

Publication number Publication date
CN1214383C (zh) 2005-08-10
WO2001057867A2 (fr) 2001-08-09
WO2001057867A3 (fr) 2002-04-18
CN1381047A (zh) 2002-11-20
JP2003521791A (ja) 2003-07-15

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