EP0888676A1 - Procede d'application de filigrane efficace contre les copies illicites - Google Patents

Procede d'application de filigrane efficace contre les copies illicites

Info

Publication number
EP0888676A1
EP0888676A1 EP97909004A EP97909004A EP0888676A1 EP 0888676 A1 EP0888676 A1 EP 0888676A1 EP 97909004 A EP97909004 A EP 97909004A EP 97909004 A EP97909004 A EP 97909004A EP 0888676 A1 EP0888676 A1 EP 0888676A1
Authority
EP
European Patent Office
Prior art keywords
copy
watermarks
watermark
work
watermarked
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Withdrawn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
EP97909004A
Other languages
German (de)
English (en)
Inventor
Frank T. Leighton
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.)
Individual
Original Assignee
Individual
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 US08/615,534 external-priority patent/US5664018A/en
Application filed by Individual filed Critical Individual
Publication of EP0888676A1 publication Critical patent/EP0888676A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/76—Television signal recording
    • H04N5/91—Television signal processing therefor
    • H04N5/913—Television signal processing therefor for scrambling ; for copy protection
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F21/00—Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
    • G06F21/10—Protecting distributed programs or content, e.g. vending or licensing of copyrighted material ; Digital rights management [DRM]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F21/00—Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
    • G06F21/10—Protecting distributed programs or content, e.g. vending or licensing of copyrighted material ; Digital rights management [DRM]
    • G06F21/16—Program or content traceability, e.g. by watermarking
    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
    • H04N1/32149—Methods relating to embedding, encoding, decoding, detection or retrieval operations
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
    • H04N1/32149—Methods relating to embedding, encoding, decoding, detection or retrieval operations
    • H04N1/32288—Multiple embedding, e.g. cocktail embedding, or redundant embedding, e.g. repeating the additional information at a plurality of locations in the image
    • H04N1/32304—Embedding different sets of additional information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
    • H04N1/32149—Methods relating to embedding, encoding, decoding, detection or retrieval operations
    • H04N1/3232—Robust embedding or watermarking
    • 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
    • G06T2201/0063—Image watermarking in relation to collusion attacks, e.g. collusion attack resistant
    • 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
    • G06T2201/0081—Image watermarking whereby both original and watermarked images are required at decoder, e.g. destination-based, non-blind, non-oblivious
    • 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
    • G06T2201/0083—Image watermarking whereby only watermarked image required at decoder, e.g. source-based, blind, oblivious
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/76—Television signal recording
    • H04N5/91—Television signal processing therefor
    • H04N5/913—Television signal processing therefor for scrambling ; for copy protection
    • H04N2005/91307—Television signal processing therefor for scrambling ; for copy protection by adding a copy protection signal to the video signal
    • H04N2005/91335—Television signal processing therefor for scrambling ; for copy protection by adding a copy protection signal to the video signal the copy protection signal being a watermark
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N2201/3201—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N2201/3225—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of data relating to an image, a page or a document
    • H04N2201/3233—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of data relating to an image, a page or a document of authentication information, e.g. digital signature, watermark
    • H04N2201/3236—Details of authentication information generation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N2201/3201—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N2201/3225—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of data relating to an image, a page or a document
    • H04N2201/3233—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of data relating to an image, a page or a document of authentication information, e.g. digital signature, watermark
    • H04N2201/324—Selecting a particular authentication information from amongst a plurality of different authentication information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N2201/3201—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N2201/3269—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of machine readable codes or marks, e.g. bar codes or glyphs
    • H04N2201/327—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of machine readable codes or marks, e.g. bar codes or glyphs which are undetectable to the naked eye, e.g. embedded codes

Definitions

  • the present invention relates generally to preventing unlawful copying of audio, video and other media that can be digitized and, more particularly, to improved watermarking techniques that are robust even against multiple individuals who conspire together with independent copies.
  • a "watermark” is a visible or preferably invisible identification code that is permanently embedded in the data and thus remains present within the data after any decryption process.
  • a digital watermark would be a visible "seal" placed over an image to identify the copyright owner.
  • the watermark might also contain additional information, including the identity of the purchaser of a particular copy of the material.
  • Many schemes have been proposed for watermarking digital data. In a known watermarking procedure, each copy of a document D is varied slightly so as to look the same to the user but also so as to include the identity of the purchaser.
  • the watermark consists of the variations that are unique to each copy. The idea behind such schemes is that the watermark should be hard to remove without destroying the document. Thus, a copy of a watermarked document should be traceable back to the specific version of the original from which it was created.
  • each of a set of copies of the work has a slightly-modified form of a "baseline” watermark that is placed within a critical region of the data.
  • the slight variations in the watermarks are not perceptually visible and do not interfere with the works. If multiple persons collude to attempt to create an "illicit" copy of the work (i.e., a copy without a watermark), however, at least one of the modified watermarks is present in the copy, thereby identifying both the illicit copy and the copier.
  • the work to be protected is digitized into a data file or string of data.
  • a first digital watermark is then inserted in a first copy of the data file, preferably in a critical region of the data.
  • a "critical" region may consist of the entire document or alternatively will be some valuable portion of the work that will end up being significantly corrupted if the watermark is corrupted.
  • a second digital watermark is then inserted in a second copy of the data file in a similar manner, and the process is repeated for additional copies.
  • the first and second digital watermarks are slight variations of a "baseline" watermark, which is kept secret, and one cannot perceive any differences between the first and second copies due to these variations.
  • the baseline watermark may be a digital string that is part of the original data being protected.
  • the variations are "randomized” in such a manner that if two persons were to collude to attempt to create an "illicit" copy of the work (i.e., a copy without a watermark), at least one of the first or second watermarks would still be present in the copy. After the watermark is inserted into the work, the work can be converted back to its original form.
  • the scheme ensures that different possessors of watermarked copies of a work cannot create a "clean" copy that does not include at least one of the slightly-modified watermarks. Indeed, by comparing the watermark of the illicit copy with the baseline watermark, one can determine the identity of the forger.
  • FIGURE 1 is a block diagram illustrating the method of inserting a digital watermark into a copy
  • FIGURE 2 is a block diagram illustrating the method for retrieving a digital watermark from a copy and correlating the retrieved watermark with a stored watermark.
  • the work to be protected may be an image (photographs and graphics), video and/or audio (speech and music).
  • image photographs and graphics
  • video and/or audio speech and music
  • the particular type of work is not relevant to the invention.
  • the work in whatever form, is digitized at step 10 into a data file or string of data either as part of the inventive technique or through some known A/D preprocessing.
  • a “baseline” watermark that is preferably stored and not used in making a particular copy of the work (although this step is not necessarily required).
  • This baseline watermark is then processed to create a set of one or more "modified" watermarks, each of which is related to the baseline watermark in a predetermined manner.
  • the "offsets" needed to create the modified watermarks are not fixed, however, but are "randomized.” In this way, a very small amount of "noise” is added to the offsets that does not alter the perception of the watermarked copies but still ensures that possessors of such copies cannot collude to remove all existence of the watermark in at least one illicit copy.
  • collusion-type attacks are prevented according to the invention by constructing a watermark using randomness in a specific way.
  • an n-length digital string: XT ,X 2 ...,x n is derived at step 1 2 from the data to be watermarked and stored at step 14 for future reference. This may be referred to as the "baseline" watermark.
  • the string is preferably "critical" to the data in that corruption of the string will corrupt the data in a way that can be perceived and which will diminish the value of the corrupted document.
  • Generation of the baseline watermark can be achieved in many ways, e.g., by digitizing some portion of the document and using the resulting data or some subset thereof. (Whatever method is used is also used in the verification process, as discussed below).
  • An n-length watermark vector 1 ( w 2 , ...w n , is then created at step 1 6 and stored at step 1 8 for future reference.
  • the vector is preferably created by choosing each w, from a specified random distribution (preferably the normal distribution).
  • may or may not be the same (e.g., depending on whether it is desired to embed some specific serial number data in the watermark).
  • the watermark vector is then added at step 20 to the string x 1 ,x 2 , ..., x n . and the result reinserted at step 22 into the original data to be protected.
  • the work may then be converted back to its original form (image, video, audio, etc.) at step 24.
  • step 34 by retrieving the original base line watermark, x 1 f x 2 , ...x n , from memory and subtracting out x 1 ,x 2 , ...x n from x ',x 2 '' —* n to compute a derived watermark w 1 ',w 2 ', ...w n ' at step 36.
  • a correlation value (preferably an inner product) is then calculated between the derived watermark and w ( w 2 , ... w n retrieved at step 38, to produce a correlation value at step 40.
  • the correlation value is compared at step 42 to threshold levels, and if the correlation is high (step 44), then there is a match and a watermark is present. If the correlation is low (step 46), the watermark is not present.
  • the inner product scheme works by computing the absolute value of the sum WT W-I ' + ... + w n w n ').
  • a first digital watermark is inserted in a first copy of a data file, preferably in a critical region of the data.
  • a second digital watermark is then inserted in a second copy of the data file in a similar manner, and the process is repeated for additional copies.
  • the first and second digital watermarks are slight variations of a "baseline” watermark, which is kept secret, and one cannot perceive any differences between the first and second copies due to these variations.
  • the variations are "randomized” in such a manner that if two persons were to collude to attempt to create an "illicit" copy of the work (i.e., a copy without a watermark), at least one of the first or second watermarks would still be present in the copy.
  • the watermark may consist of a number (e.g., 1000) of randomly generated numbers with a normal distribution having zero mean and unity variance.
  • could be selected according to N( ⁇ j, ⁇ ,) where ⁇ ... ⁇ n can be a serial number corresponding to the copy being watermarked (or other information that may be embedded).
  • cor(W,W)
  • the correlation will be low if the watermark is not present and the work is not destroyed.
  • the correlation will be high if D' was derived from the watermarked document or if the data has been corrupted beyond recognition (the latter condition being determined by inspection).
  • each of the "modified" watermarks be placed in a critical region of the data.
  • the exact location will depend on the nature of the work being protected. It is also helpful if every entry in this region of data is largely uncorrelated with the other data. It has been suggested (by Cox et al) that this can be accomplished by embedding a watermark in the spectrum of an image, the temporal frequency domain of an audio signal, or the spatio-temporal frequency domain of a video sequence.
  • the above techniques are preferred, one may even encode the watermark in other less, desirable places (such as in the low order or least significant bits) of the data and still obtain the advantages of the collusion-resistant feature of the invention where multiple parties may collude to remove the watermark. Variations
  • the original document (or an original baseline watermark vector) is stored in order to determine whether the watermark is present in a copy of the document.
  • the original baseline watermark vector is retrieved at step 34 and subtracted from the derived baseline watermark vector to produce the derived offset watermark vector. This step can be omitted without changing the detection protocol or its results.
  • the derived offset watermark vector may be set equal to the derived baseline watermark vector. This change increases the noise level in the correlation test, but not beyond tolerable levels.
  • the noise levels can be reduced by specially selecting the original offset watermark vectors to have low noise (e.g., by selecting them to be orthogonal to the original baseline watermark vector to which they are being applied) or by running the correlation test on only specific components of the vectors.
  • Another improvement would be to remove the need to store the original offset watermark vector.
  • it is necessary to store a copy of the original offset watermark vectors see, e.g., step 18) so that they can be later retrieved and correlated with the derived offset watermark vectors (see, e.g., step 38).
  • This step can be largely omitted by the following process.
  • the original offset watermark vectors are computed using a secret random hash function H.
  • the sequence of numbers preferably has same structure and function as discussed above and appear to be random, but the sequence is easily reconstructed given the secret function H and the underlying information to be inserted into the document. Hence, a watermark is identified by reconstructing the original offset watermark vector locally instead of retrieving the vector from a database.
  • the text to be embedded may be a simple serial number, and this serial number can be retrieved from the document by checking all possibilities to see if there is a correlation. This check can be done locally if H is available, since all relevant original offset vectors can be regenerated as needed.
  • the correlation test generates the old dot product (which is large, precisely what is desired) plus the dot product of the offset vector and the original picture. Since the offset vector is random, this dot product is small (in the noise range) for any picture. Therefore, one does not need the original picture to do the correlation test.
  • the secret random hash function H maps a copyright notice or text into a sequence of independent Gaussian offsets (i.e., an offset vector). Then, one may choose the offset vector for some text to be H(text). Now, one need only remember the text, not the whole offset vector. The text may be timestamped so that the same offset vector is only used once, although one can use the same offset vector more than once.
  • This method is provably secure, even against colluders, but has low memory requirements.
  • a two-tiered version, wherein there are two hash functions (one for the sign and one for the magnitude of the offsets) might be used as well. In this way, one of the two (sign or magnitude) would be kept in reserve and not released, even in the secure software.
  • the hardware/software that creates the watermarks is in secure hands (so that H remains secret and cannot be misused). For example, if the adversary is allowed to watermark a blank document, then the scheme can lose security. There are several ways, however, that security can be enhanced as is now explained. In one approach, it is assumed that each copy of the watermarking software produces watermarks unique to the copy. For example, the XYZ Corporation watermarking software produces watermarks of the form H(XYZCORP
  • the original offset watermark vectors can be derived as a function of the document that is being watermarked in addition to the text that is being embedded into the document. This has the effect of making watermarks corresponding to "Do not copy" be different for each document in which they appear. For example, one might use H(x_1 ...X_n

Abstract

On numérise (10) tout d'abord l'oeuvre à protéger par un filigrane, ensuite on dérive (12) un vecteur de filigrane de base et on le mémorise (14). De plus, on crée (16) et on mémorise (18) un vecteur de filigrane décalé. Ensuite, on ajoute le vecteur de filigrane décalé au vecteur de filigrane de base, pour créer un vecteur (20) de filigrane modifié. Puis, on remplace le vecteur de filigrane de base par le vecteur de filigrane modifié dans l'oeuvre numérisée à protéger (22). Enfin, on ramène l'oeuvre filigranée à sa forme d'origine (24).
EP97909004A 1996-03-12 1997-03-12 Procede d'application de filigrane efficace contre les copies illicites Withdrawn EP0888676A1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US08/615,534 US5664018A (en) 1996-03-12 1996-03-12 Watermarking process resilient to collusion attacks
US615534 1996-03-12
US67986396A 1996-07-15 1996-07-15
US679863 1996-07-15
PCT/US1997/003816 WO1997034391A1 (fr) 1996-03-12 1997-03-12 Procede d'application de filigrane efficace contre les copies illicites

Publications (1)

Publication Number Publication Date
EP0888676A1 true EP0888676A1 (fr) 1999-01-07

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP97909004A Withdrawn EP0888676A1 (fr) 1996-03-12 1997-03-12 Procede d'application de filigrane efficace contre les copies illicites

Country Status (3)

Country Link
EP (1) EP0888676A1 (fr)
AU (1) AU2076097A (fr)
WO (1) WO1997034391A1 (fr)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IL124595A (en) 1998-05-21 2009-09-01 Yossef Tsuria Anti-piracy system
JP3868643B2 (ja) * 1998-12-03 2007-01-17 株式会社日立製作所 デジタル情報複製制限方法、デジタル情報複製制限装置およびデジタル情報記録装置
IL129725A (en) 1999-05-02 2011-06-30 Nds Ltd Watermark system
JP3735521B2 (ja) * 1999-09-30 2006-01-18 株式会社東芝 埋め込み符号生成方法及び装置、埋め込み符号検出方法及び装置並びに電子透かし埋め込み装置
US6754364B1 (en) 1999-10-28 2004-06-22 Microsoft Corporation Methods and systems for fingerprinting digital data
US6807634B1 (en) * 1999-11-30 2004-10-19 International Business Machines Corporation Watermarks for customer identification
US6859217B2 (en) 2000-07-19 2005-02-22 Microsoft Corporation System and method to display and manage data within hierarchies and polyarchies of information
US6957230B2 (en) 2000-11-30 2005-10-18 Microsoft Corporation Dynamically generating multiple hierarchies of inter-object relationships based on object attribute values
US7047413B2 (en) 2001-04-23 2006-05-16 Microsoft Corporation Collusion-resistant watermarking and fingerprinting
US6952704B2 (en) 2001-11-26 2005-10-04 Microsoft Corporation Extending a directory schema independent of schema modification
US6944626B2 (en) 2001-11-26 2005-09-13 Microsoft Corp. Dynamically generated schema representing multiple hierarchies of inter-object relationships
US7389335B2 (en) 2001-11-26 2008-06-17 Microsoft Corporation Workflow management based on an integrated view of resource identity

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5488664A (en) * 1994-04-22 1996-01-30 Yeda Research And Development Co., Ltd. Method and apparatus for protecting visual information with printed cryptographic watermarks
US5530759A (en) * 1995-02-01 1996-06-25 International Business Machines Corporation Color correct digital watermarking of images

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9734391A1 *

Also Published As

Publication number Publication date
WO1997034391A1 (fr) 1997-09-18
AU2076097A (en) 1997-10-01

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