JP2011139541A - System for controlling distribution and use of digital work - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and system for controlling the distribution and use of digital works. <P>SOLUTION: A usage right repository determines a usage right designating how a first document is to be utilized or distributed. The usage right includes information on embedding of a watermark into a second document, and the second document is generated as a result of exercising the usage right for the first document. A data repository collects watermark data while the usage right is exercised for the first document. A watermark repository generates the watermark on the basis of the collected watermark data and, according to the information included in the usage right, the generated watermark is embedded in the second document. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to the field of implementation of distribution rights and usage rights for digitally encoded work, and in particular to identifying unauthorized copies of digitally encoded work that has already been rendered.

  Patent Document 1 (issued on May 13, 1997) entitled “System for Controlling the Distribution and Use of Digital Works” is a digitally encoded work ( (Hereinafter, referred to as digital work) distribution protection and a system for compensating for this. However, if a digital work leaves the digital domain (eg, printed, played back, or rendered), the digital work is no longer protected and can be copied without permission. This is a problem for all rendered digital work.

Two known techniques for protecting a digital work by adding information to the digital work itself are "watermarking" and "fingerprinting". Historically, the term watermark refers to a translucent pattern (design) that is stamped on a paper in the manufacturing stage and visible when the paper is viewed through light. Since the watermark is stamped using a combination of water, heat, and pressure, it is not easy to add or change the watermark outside the paper mill. Watermarks are used when creating letterheads to show that their origins and documents are fair and original and not duplicates.

  The term watermark is now used to encompass a wide range of technologies for marking rendered work (including text, digital images, and digital audio) with information that identifies the work or publisher. Some watermarks are noticeable, others are hidden. Information embedded in one type of watermark can be read by a person, but information embedded in another type of watermark can only be read by a computer.

  The term fingerprint is sometimes used in contrast to a watermark and refers to a mark that holds information about the end user and the rendering event rather than the document or publisher. These marks are called "fingerprints" because they can be used to track where they were copied and locate the person or computer that rendered the original.

US Pat. No. 5,629,980

  These types of marks and mark techniques can be used to carry both watermark and fingerprint information. In fact, this is not only possible, but it is often desirable and convenient to combine both types of information (watermarks and fingerprints) into a single mark.

A first aspect of the invention is a method for controlling the distribution and usage of a document, the method comprising: how a usage rights repository is used or distributed for a first document; A usage right that includes information about embedding a watermark in a second document, the second document being a result of exercising the usage right with respect to the first document And the data repository collects watermark data while the usage rights are exercised for the first document, and the watermark repository generates a watermark based on the collected watermark data. , The generated water in the second document according to the information included in the usage right Embed chromatography click involves.
A second aspect of the present invention is a system for controlling the distribution and use of a document, the system specifying how the first document is used or distributed. A usage rights repository for determining the usage rights, wherein the usage rights contain information about embedding a watermark in a second document, the second document exercising the usage rights with respect to the first document And a data repository for collecting watermark data while the usage rights are exercised with respect to the first document, and generating a watermark based on the collected watermark data, In accordance with the information included in the usage right, the generated waterma is added to the second document. Including a watermark repository to embed a click.

  A trusted rendering system for use in a system for controlling the distribution and use of digital work is disclosed. The preferred embodiment of the present invention is implemented as a trust printer. However, the description of the invention described herein is suitable for any rendering device (reproduction device). Trust printers facilitate the protection of printed documents printed from systems that control the distribution and use of digital work. A system for controlling the distribution and use of digital work gives permanent use rights to the digital work. The digital work is transferred in an encrypted form between the repository (storage location) and the repository. The repository is used to request and grant access to digital work. Such repositories are also connected to a credit server that pays for any charges generated as a result of accessing or using the digital work.

  The present invention extends the existing capabilities of the system for controlling the distribution and use of digital work and provides a means of protection when a document is printed. The present invention adds to this system the ability to add watermark information to a document when it is rendered (i.e., when a print right associated with the document is executed). In the preferred embodiment of the trusted printer, the watermark is visible, but other “invisible” watermarking techniques may also be used. The watermark data typically provides information regarding the owner of the document, rights regarding the copy of the document, and information regarding the rendering event (eg when and where the document was printed). This information generally helps to prevent or prevent unauthorized copying of rendered work. It is worth noting that the present invention provides more types of watermarks on the same digital work.

FIG. 3 is a block diagram showing basic interactions between repositories divided by repository type in a system for controlling the distribution and use of digital work in the presently preferred embodiment of the present invention. Fig. 4 represents a repository connected to a usage fee reporting credit server, such as used in a system for controlling the distribution and usage of digital work in the presently preferred embodiment of the invention. FIG. 2 represents a printer as a rendering system, such as used in a system for controlling the distribution and utilization of digital work in the presently preferred embodiment of the present invention. FIG. 4 is a block diagram showing functional elements of a trust printer repository in the presently preferred embodiment of the present invention. Fig. 4 represents a flow chart of the basic steps for generating digital work for printing on a trusted printer, as implemented in the presently preferred embodiment of the invention. In the presently preferred embodiment of the present invention, a representation of a usage right for a digital work printed on a user's trusted printer is presented. Fig. 3 represents a usage right notation for a digital work that can only be printed by a shared trust printer on the network in the presently preferred embodiment of the present invention. Represents a printed page with a watermark encoded glyph. Fig. 4 represents a set of sample embedded data boxes with different capacities, such as used as watermark characters in a watermark font set in the presently preferred embodiment of the present invention. Represents a printing right having watermark information specified as a set used in the presently preferred embodiment of the present invention. Fig. 4 represents a flow chart summarizing the basic steps for an author to place a watermark in his document as performed in the presently preferred embodiment of the invention. Fig. 4 represents a flowchart of the steps required for document printing as performed in the presently preferred embodiment of the invention. Fig. 4 represents a flow chart of an outline of basic steps for embedded data extraction as performed in the presently preferred embodiment of the present invention.

  The risk of unauthorized copying of digital documents (risks) occurs mainly by the following three methods. The first is the digital copy interception (interruption) when the digital copy is sent (eg, by wire [telephone] wiretapping (wiretapping or packet snooping)), the second is remotely stored The unauthorized use and rendering of digital copies, and the third, unauthorized copies of rendered digital work, and the design of the trust rendering device described herein is concerned with all these risks.

Trust regeneration is a combination of four elements: usage rights terminology, encrypted online distribution, automatic charge for copying fees, and a digital watermark for marking the rendered copy.
Usage rights term: The content provider indicates the time, conditions, and fees for printing the document in machine-readable property rights terms.
Encrypted distribution: Digital work is distributed from the trust system to the trust rendering device via the computer network. The digital work is encrypted to reduce the risk of the digital work being interrupted without permission during transmission. Communication with the rendering system is performed by a request-response protocol that confirms the permissions and security of the rendering device.
• Automatic billing: To ensure a reliable deposit flow to the content provider, the usage bill is automatically made online.
Watermark: Finally, to reduce the risk of the rendered work being copied, the rendered work is watermarked and data about the digital work and rendering events is recorded. In addition, the watermark is designed to distinguish the copy from the original. As described below, watermark information is specified in terms of usage rights within the scope of rendering or playback rights.

  The preferred embodiment of the present invention is implemented as a trust printer. Although the preceding description relates primarily to printers, the concepts and techniques described therein apply equally to other types of rendering systems (eg, audio players, video players, displays, multimedia players, etc.).

  A preferred embodiment of the present invention is disclosed in US Pat. No. 5,629,980 issued under the title “System for Controlling the Distribution and Use of Digital Works”. Operating in a system for controlling the distribution and utilization of digital work as described in the issue (incorporated herein by reference). Digital work can be written, audio, graphic, or video-based, including computer programs that can be translated into digital form or generated in digital form and regenerated using suitable rendering means such as software programs. It can be any work. With this system, the owner of a digital work can attach a usage right to the work. The right to use a work defines how it is used and how it is distributed. Digital works and their usage rights are stored in a security repository. Digital work can only be accessed by other security repositories. A repository is protected if it possesses a valid identification (digital) certificate issued by a master repository and can prove that identification in a request response protocol.

  Usage rights terms for controlling digital work are defined by flexible (flexible) and extensible usage rights grammars. Conceptually, a right written in a usage rights grammar is a label attached to a given action and defines the conditions for implementing that right. For example, the COPY right indicates that a digital work may be copied. A condition for enforcing this right is that the requester (client) must pass certain security standards. There may be conditions that restrict the rights themselves. For example, the LOAN right may be defined to limit the period during which the work is “LOANed”. In addition, there may be a requirement for fee payment.

  The repository includes a storage means for storing a digital work and a usage right attached thereto, an external interface for receiving and transmitting data, a processor, and a clock. The repository generally has two main modes of operation: a server (supplier) mode and a requester (requester) mode. The repository responds to an access request to the digital work when operating in the server mode, and makes an access request to the digital work when operating in the requester mode.

  In general, the repository processes each access request to a digital work by examining the usage rights for that work. For example, in a digital work copy request, the digital work is checked to see if it is granted such "copy" rights, and then the conditions for performing that right (eg, the right to make two copies) Is checked. If the condition regarding the right is satisfied, the copy can be made. Any specified changes to the rights set for a copy of a digital work are attached to the copy of the digital work prior to transferring the digital work.

  The repository communicates using a set of repository transactions. Repository transactions include a set of protocols for establishing a secure (hereinafter confidential) session connection between repositories and for processing access requests to the digital work. Note that digital work and various communications are encrypted whenever they are transmitted between repositories.

  Digital work is played back in a rendering system. A rendering system comprises at least a rendering repository and a rendering device (eg, a printer, display, or audio system). The playback system is internally secure. Access to a digital work that is not stored in the rendering repository is through a repository transaction with an external repository that contains the desired digital work. As described in more detail below, the presently preferred embodiment of the present invention is implemented as a rendering system for printing digital work.

  FIG. 1 shows the basic interaction (interaction) between repositories classified according to type in the present invention. As is apparent from FIG. 1, various types of repositories provide different functions. It is fundamental that multiple repositories share a set of core functions that can enable secure and reliable communication. Referring to FIG. 1, repository 101 represents a general instance of a repository. The repository 101 has two operation modes: a server mode and a requester mode. The repository receives and processes an access request to the digital work in the server mode, and activates an access request to the digital work in the requester mode. The repository 101 can communicate with a plurality of other repositories, namely, the authorization repository 102, the rendering repository 103, and the master repository 104. Communication between repositories is performed using the repository transaction protocol 105.

  Communication with the authorization repository 102 occurs when the digital work being accessed has conditions that require authorization. Conceptually, permission is a digital certificate that requires possession of a certificate (certificate) to gain access to the digital work. Permission itself is a digital work that can be moved between repositories and can be left to fees and usage rights terms. Authorization may be required by both repositories involved in accessing digital work.

  Communication with the rendering repository 103 is performed in connection with the rendering of the digital work. As described in more detail below, a rendering system is configured by combining a rendering repository with a rendering device (eg, a printer device).

  Communication with the master repository 104 is performed in connection with acquisition of identification (ID certification). Identification is the means used to recognize a repository as "trustworthy". The use of identification is described below with respect to registration transactions.

  FIG. 2 shows the repository 101 connected to the credit server 201. The credit server 201 is a device that accumulates billing for the repository 101. The credit server 201 communicates with the repository 101 via the billing transaction 202 and records the billing transaction. Billing transactions are periodically reported by the credit server 201 to a billing clearinghouse 203. Credit server 201 communicates with fee clearing house 203 via clearing house transaction 204. The clearing house transaction 204 enables secure encrypted transmission of information to the charge clearing house 203.

  A rendering system is generally defined as a system that includes a repository and a rendering device that can render a digital work in a desired format. The rendering system may be a computer system, a digital audio system, or a printer. In the preferred embodiment, the rendering system is a printer. In any case, the rendering system has a feature of repository security. The combination of the rendering repository and the rendering device can be done in a manner suitable for the type of rendering device.

  FIG. 3 represents a printer as an example of a rendering system. Referring to FIG. 3, the printer system 301 includes a printer repository 302 and a printer device 303. Note that the dashed lines that define the printer system 301 define safe system boundaries. Communication within this boundary is assumed to be secure and clear (ie not encrypted). In some security sebels, this boundary also represents a barrier that aims to provide physical integrity. A printer repository 302 embodies the rendering repository 103 of FIG. The printer repository 302 optionally includes a temporary copy of the digital work (this copy remains until it is printed out by the print engine 303). In other cases, the print repository 302 may include digital work, such as fonts, that remains and is charged for use. This design ensures that all communication lines between the printer repository and the printing device are encrypted except when they are within physically safe boundaries. This design feature removes potential "failure" points through which digital work can be unfairly acquired. Printer device 303 represents a printer component used to generate print output.

  FIG. 3 also shows the repository 304. The repository 304 is connected to the printer repository 302. A repository 304 represents an external repository that includes digital work.

  FIG. 4 shows the functional elements of the trust printer repository. Note that these functional elements are also present in every rendering repository. Referring to FIG. 4, this functional unit includes an operating system 410, a core repository service 411, and a print repository function 412. The operating system 410 is specific to that repository and is typically based on the type of processor used to implement the repository. The operating system 410 also provides a basic server for controlling and interfacing between the basic components of the repository.

  The core repository service 411 includes a set of functions required by each and every repository. In the trusted printer repository, the core repository service is concerned with the request response protocol for receiving the digital work and the decryption of the received digital data.

  The print repository function 412 includes functions for rendering and printing the work and collecting and generating data for the digital watermark. Features unique to the print repository will become apparent from the following description, particularly the description of the flowchart of FIG.

  FIG. 5 represents a flowchart representing the basic steps for generating a digital work that can be printed on a trusted printer so that the final printed document is also secure. It should be noted that many well-known execution steps, such as digital work encryption, have been left out of the basic steps. First, a digital work is written, a usage right including a printing right for designating watermark information is assigned, and deposited in the repository 1 (step 501). As will be described in more detail below, usage rights are assigned using a rights editor. The fact that a digital work has been deposited in the repository 1 indicates that this digital work has been put into the controlled system. Next, repository 1 receives a request to access the digital work from repository 2 (step 502), and repository 1 transfers a copy of the digital work to repository 2 (step 503). In this example, assume that a “trusted” session has been established between repository 1 and repository 2. The request response protocol used in this interaction is disclosed in the aforementioned U.S. Pat. No. 5,629,980, so there is no need to further describe the request response protocol.

  Repository 2 then receives a user request to print the digital work (step 504). Repository 2 then establishes a trust session with the printer repository of the printing system from which the digital work will be printed (step 505). The printer repository receives the encrypted digital work and checks whether this work has a print right (step 506). If the digital work has a print right, the printer repository decrypts the digital work to generate a watermark, and the watermark is printed on the digital work (step 507). Next, the printer repository transmits the decrypted digital work with the watermark to the printer device for printing (step 508). For example, the decrypted digital work may be a digital work Postscript (trademark).

  The main concept in managing digital work governing sale, distribution, and usage is that issuers can assign "rights" to work that specify terms and conditions of use. These rights are expressed in terms of rights as described in the aforementioned US Pat. No. 5,629,980. For a number of reasons, it is advantageous to specify watermark information within its grammar within the scope of rendering or playback rights. First, the notation written in this way is technically independent. Thus, different watermark techniques can be used or changed without changing the digital document. Second, multiple watermarking technologies (eg, visible watermark technology and invisible watermark technology) can be applied to the same digital work. Therefore, even if a visible watermark is deleted, an invisible watermark remains. Third, the watermark information attached to the digital work may be related to a rendering event rather than a distribution result. Fourth, the watermark information can be extended to include the entire digital work distribution chain. Fifth, the security and watermarking function of the rendering system may be specified as a rendering condition. This will further ensure trust rendering of digital work.

  As a result of these benefits, the specification of this type of watermark information fully supports digital work superdistribution. Superdistribution is a distribution concept that takes into account all subsequent distributions where every processor of a digital work can also be a distributor of the digital work.

  When the issuer assigns rights to the digital work, the issuer can distinguish between viewing (or reproduction) rights and printing rights according to the usage rights. The reproduction right is used to make a temporary copy of a work such as a text image on a display or music sound from a speaker. Printing rights are used to make persistent copies, such as audio recordings on pages and magnetic media from laser printers.

  FIG. 6 is an example of usage rights for a digital work that enables trust (trusted) printing from a personal computer. Referring to FIG. 6, various tags for digital work are used. Tags “description” 601, “work-ID” 602, and “owner” 603 provide identification information (ID information) for the digital work.

  Usage rights are specified individually and as part of a group of rights. Rights group 604 is named “regular”. This bundle label provides a minimum security level 606 that applies to the payee 605 and all rights in the group. The payee 605 indicates a person who is paid for the execution of the right. The minimum security level 606 is used to indicate the minimum security level for the repository that wishes to access the associated digital work.

  Next, the rights within the group are specified individually. This usage right does not indicate a charge for transfer 608, deletion 609, or playback 610, but when using digital copy 607, the charge is $ 5. The usage right also has two printing rights 611 and 612, both of which require a trusted printer (designated by 613). The first printing right 611 can be used when the user has a specific prepaid ticket (prepaid ticket, designated by 614). The second print right has a flat fee of $ 10 (designated by 615). In this example, a copy right can be implemented and a digital work can be sent to the user's computer, and the user can play or print the work using play and print rights at his / her convenience. Suppose you can. The fee is recorded from the user's workstation each time the right is executed.

  FIG. 6 shows watermark specifications 616 and 617. Specific details of the watermark specifications 616 and 617 are described below with reference to FIG.

  FIG. 7 represents a different set of rights for the same digital book. In this version, the issuer does not want digital transmission to the customer's workstation. Practical aspects in support of this choice are that the issuer wants to minimize the risk of unauthorized digital copying and is more than provided by the trust system on the available workstation Of high security. Instead, the publisher wants to send the book directly from the online book store to the trusted printer. Printing must be prepaid with a digital ticket (see fee statement 701). In order to allow digital distribution to authorized distributors rather than directly to the customer, the issuer is authorized by both parties in the copy and transfer rights (ie distributor and customer) to authorize digital licenses (see certification specifications 72 and 73). It is necessary to have. Without such a license, the customer cannot access the work at the workstation. Instead, he / she must print the work.

  FIG. 7 also shows a watermark specification 704. The watermark specification 704 will be described in more detail below with reference to FIG.

Here are three main requirements for watermarking on a trusted printer:
Social reminder: This requirement is for a visible printed indication of whether photocopy is allowed. This may be a description printed on the document indicating the security level of the document or an icon or symbol defined internally.
Audit: This requirement is the result of printing, such as who has the right to print, whether photocopy is allowed, who or which printer printed the document, and when the document was printed This is because of how to record information about the document.
Copy search: This requirement is a way to make a difference between a printed original and a photocopy. In general, this requirement involves using printed patterns on the page that tend to be deformed by photocopiers and scanners. In some patterns, the difference between the copy and the printed original can be detected by the human eye, while in other patterns it can be detected by a computer using a scanner.

  In a preferred embodiment, the watermark is generated using an embedded data technique such as the glyph technique developed by Xerox Corporation. Glyph technology used as embedded data printed on media was entitled "Hardcopy Lossless Data Storage and Communications For Electronic Document Processing Systems" U.S. Pat. No. 5,486,686, the disclosure of which is incorporated herein by reference. Using glyphs as digital watermarks on printed documents means that “Quasi-Reprographics With Variable Embedded Data With Applications To Copyright Management,” which applies various embedded data to copyright management and distribution control. Distribution Control, etc.) ”in pending US patent application Ser. No. 08 / 734,570. This patent is assigned to the assignee of the present invention and is incorporated herein by reference.

  In general, embedded data technology is used to attach machine readable data on printed media. Machine-readable data is often in encoded form that is difficult if not impossible for humans to read. Another example of embedded data technology is barcode.

  Embedded data technology can be used to hold hundreds of bits of embedded data per square inch in various achromatic patterns (gray patterns) on a page. Preferably, glyphs are used because the marks representing the encoded data are used to generate more aesthetically appealing marks than other embedded data techniques. If designed carefully, glyphs can be integrated with graphic elements in the page layout. Glyphs can be used with any kind of document. The glyph watermark that holds the document ID (identification) can be embedded by the issuer, but the glyph with data about the print result can be added to the watermark when the printing system is printing. it can. Both document ID and fingerprint data can be embedded in the same watermark.

  The disadvantage of using glyphs and all types of visible separable watermarks is that they can be removed from the document by mechanical or computer work.

  FIG. 8 shows an example of a document image having a watermark with embedded glyphs. Referring to FIG. 8, the document page 801 has various texts 802. Also included is a watermark 803 with embedded glyphs. Note that a document is not limited to text but may include images and graphic data.

  This section briefly describes how embedded data technology can be used in a trust printing system to embed watermark data. Describes how glyph and watermark data are processed at each stage of document generation, publication, and printing.

・ In order to integrate embedded data such as glyphs into the trust printing system, it was decided to include the following necessary items.
-Document designers (designers) such as authors and publishers must specify the location and shape of the watermark on the page for each page so that the watermark can be incorporated into the design of the document. Don't be.
This method must be compatible with mainline document generation (eg word processor) systems.
This method must work within the existing printer protocol. • This method must retain fingerprint (or runtime) data in the usage rights specification.
• This method should not slow down the printing speed significantly.

  In this specification, the term “media-dependent data” is used to refer to information about how the watermark is located and formed in the document content. In this method, data is encoded in a watermark depending on how the usage right is used.

  Publishers create documents using many different tools. Different text editors or word processors have different ways and degrees to control the layout of text, pictures, and diagrams they provide. One thing all text editors have is a way to position text on a page. In fact, this is the least common divisor (minimum common function) of all system functions (capabilities).

By developing this common functionality, we can gain insight into how glyphs are used to represent watermarks.
Glyph watermarks are organized like graphics as rectangular boxes. • Different sized boxes have different data capacity capabilities. A 300 dpi printer can encode about 300 bytes per inch into a glyph. Note that this can represent more data if the original data is compressed before encoding the glyph. Note that some data may be redundantly repeated to increase reliability, but this is an exchange of reliability and data capacity.
Each glyph watermark is displayed in the document creation program as a character in the initial glyph watermark font. Boxes of different sizes and shapes are represented as different characters in the initial glyph watermark font. When a digital work is printed, the encoding of data is similar to the calculation and modification of its watermark font.

  In practice, a designer who lays out a document opens a glyph catalog page containing glyph boxes of different sizes. The glyph box in the catalog is probably test data, eg

Glyph ASCII code). The designer decides early how much data he wants to encode per page (eg, 100, 300, 500 or 1000 bytes). The designer copies a correspondingly sized "box" (actually a character) into his document and places this box anywhere on the page (typically incorporating this box as a design element) .

  FIG. 9 represents a set of sample watermark characters (ie glyph boxes) having different storage capacities. The actual catalog contains further forms and is annotated according to the data ownership of the glyph.

  Note that because the drawing program also has the ability to position characters on the page, a watermark encoded glyph can be placed in the figure.

  When the author saves his work, the document creation program writes a file in which glyph font characters are used to represent the watermark. If the author prints the document at this stage, he / she will replace the test data encoded in the gray-tone glyph box with the dynamically generated watermark data later, You will see how the final sold version (sold version) will look more or less.

  When the author or publisher is ready to publish the work and put this work into a system for controlling the distributed use of digital work, one of the steps is to use the rights editor Assigning rights to the work. The rights editor is a program used when a document owner specifies a period and conditions for using a digital work.

  At this point, document identification data and print result data are designated. FIG. 10 shows watermark information designated for the printing right. Note that the representation of the watermark information is arbitrary within the grammar. Referring to FIG. 10, the print right 1001 specifies that the purchaser of the document must pay $ 10 to print the document (charge display 1002). The document should only be printed on a given type of trusted printer (printer specification 1003). In addition, the watermark must embed a specific string "Title: Moby Dog Copyright 1994 by Zeke Jones. All Rights Reserved" and include various data about the print result (watermark token specification 1004). The watermark token specification is used to specify "fingerprint" information related to the printing of the digital work. Here, the specified print result data is who printed it, the name of the institution that printed it, the name of the printer, the location of the printer, and the time when the digital work was printed. This information is obtained when printed, as described in detail below.

  FIG. 11 shows a flow chart summarizing the basic steps for the creator to place the watermark in his document. As part of the layout of the text document, the designer determines how much data is needed for the watermark (step 1101). Based on the required amount of data, an appropriate watermark character (eg, glyph box) is selected (step 1102). The watermark characters are then placed on the digital work page (s) (step 1103). Finally, as part of the rights assignment for the digital work document, a print right having a watermark specification is created (step 1104). When the document is viewed at this point, the watermark is in a desired position on the document. However, the actual fingerprint and other data identification data have not yet been generated in the embedded data format. This is generated dynamically when printing, as described below.

  The next step for digital work is to issue and distribute this work. During this process, the digital work is protected by encryption and other security systems used and its rights move with the document. As part of this process, any printer or workstation that has a copy of the document can also have a digital certificate that includes information identifying its trust system, trust printer, user, etc. No. 5,629,980).

  FIG. 12 shows a flowchart of the steps necessary to print a document. Referring to FIG. 12, at a certain point, the user decides to print the document (step 1201). This is typically done by a print command that is invoked on the user system via some interface. This opens a request-response protocol between the “user” repository containing the document and the printer repository (step 1202). During this exchange, the printer's security and watermark capabilities are checked. If the printer does not have adequate security or watermark capability, the digital work cannot be printed by the printer. The security level and watermark capability of the printer are specified in the printer's ID certificate. If the printer has the appropriate security level and watermark, then the “user” repository then checks whether the user has the necessary printing rights (step 1203). If the user has the necessary printing rights, the user repository interfaces with the credit server to report the fee required to print the digital work (step 1204). The actual charge for the digital work occurs when the rights are invoked, either when the printing is done or when the document can be proven printed. The latter protects the user from the situation where printing can be inadvertently terminated before all digital work is printed.

  Next, a calculation is performed to collect information to be embedded in the watermark and incorporate it into a new font for the watermark characters. First, information (ie name, location, current date and time, etc.) must be collected from the digital ID certificate belonging to the user or trusted printer (step 1205). This information is "printed" into the computer memory to generate a bitmap image consisting of a plurality of differently sized glyph boxes (step 1206). Since the generation and encoding of glyphs is described in the aforementioned US Pat. No. 5,486,686, it is not considered necessary to describe the encoding of glyph patterns. In any case, this information is then assembled into a font definition (step 1207).

  The digital work is then decrypted and downloaded into the printer (step 1208). When the digital work is downloaded into the printer, the protocol part is also downloaded into the new "revised" glyph font (which now has characters corresponding to the grig box). This font is used by the publisher when generating the document, except that the data that the publisher wants to represent is embedded in the watermark of the document by the Gray code in the font box. Resembles a font.

  Next, the printer prints the digital work (step 1209). When the document is printed, the glyphs that appear on the page contain the desired watermark data.

  FIG. 13 is a flowchart showing an outline of basic steps for extracting embedded data. First, the printed document is scanned to obtain a digital representation (step 1301). Next, the position of the watermark and the corresponding embedded data is found (step 1302). The watermark can be found using a technique for finding a characteristic pixel pattern in the digital representation of the printed document. Alternatively, a template of the document may be generated that can be used to quickly locate the watermark. In any case, the embedded data is extracted from the watermark and decoded (step 1303). Next, the unencoded (decoded) data is converted into a human-readable format (step 1304). This is done on the screen or printed. The extracted data is then used to determine who and where unauthorized copying of the digital work was performed.

  It should be noted that the watermark data extraction means varies depending on the technique used to embed the watermark data. Thus, the actual extraction steps can be various, but these do not depart from the spirit and scope of the present invention.

105 repository transaction 202 charge transaction 204 clearing transaction 301 printer system 801 document page 802 text 803 watermark with embedded glyph 1001 printing right

Claims (2)

A method for controlling the distribution and use of documents, the method comprising:
The usage rights repository determines usage rights that specify how the first document is used or distributed, and the usage rights provide information about embedding the watermark in the second document. The second document is generated as a result of exercising the usage rights with respect to the first document;
A data repository collects watermark data while the usage rights are exercised for the first document;
A watermark repository generates a watermark based on the collected watermark data,
The watermark repository embeds the generated watermark in the second document according to the information included in the usage right;
A method for controlling document distribution and usage. A system for controlling document distribution and usage, the system comprising:
A usage rights repository for determining usage rights that specify how the first document is used or distributed, the usage rights for the embedding of the watermark in the second document; The second document is generated as a result of exercising the usage rights with respect to the first document;
A data repository for collecting watermark data while the usage rights are exercised with respect to the first document;
Including a watermark repository that generates a watermark based on the collected watermark data and embeds the generated watermark in the second document according to the information included in the usage right;
A system for controlling the distribution and use of documents.

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