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FIELD OF THE INVENTION
The present invention relates to the field of distribution and usage rights
enforcement for digitally encoded works.
BACKGROUND OF THE INVENTION
A fundamental issue facing the publishing and information industries as
they consider electronic publishing is how to prevent the unauthorized and
unaccounted distribution or usage of electronically published materials.
Electronically published materials are typically distributed in a digital
form and recreated on a computer based system having the capability to
recreate the materials. Audio and video recordings, software, books and
multimedia works are all being electronically published. Companies in
these industries receive royalties for each accounted for delivery of the
materials, e.g. the sale of an audio CD at a retail outlet. Any
unaccounted distribution of a work results in an unpaid royalty (e.g.
copying the audio recording CD to another digital medium.)
The ease in which electronically published works can be "perfectly"
reproduced and distributed is a major concern. The transmission of digital
works over networks is commonplace. One such widely used network is the
Internet. The Internet is a widespread network facility by which computer
users in many universities, corporations and government entities
communicate and trade ideas and information. Computer bulletin boards
found on the Internet and commercial networks such as CompuServ and
Prodigy allow for the posting and retrieving of digital information.
Information services such as Dialog and LEXIS/NEXIS provide databases of
current information on a wide variety of topics. Another factor which will
exacerbate the situation is the development and expansion of the National
Information Infrastructure (the NII). It is anticipated that, as the NII
grows, the transmission of digital works over networks will increase many
times over. It would be desirable to utilize the NII for distribution of
digital works without the fear of widespread unauthorized copying.
The most straightforward way to curb unaccounted distribution is to prevent
unauthorized copying and transmission. For existing materials that are
distributed in digital form, various safeguards are used. In the case of
software, copy protection schemes which limit the number of copies that
can be made or which corrupt the output when copying is detected have been
employed. Another scheme causes software to become disabled after a
predetermined period of time has lapsed. A technique used for workstation
based software is to require that a special hardware device must be
present on the workstation in order for the software to run, e.g., see
U.S. Pat. No. 4,932,054 entitled "Method and Apparatus for Protecting
Computer Software Utilizing Coded Filter Network in Conjunction with an
Active Coded Hardware Device." Such devices are provided with the software
and are commonly referred to as dongles.
Yet another scheme is to distribute software, but which requires a "key" to
enable it's use. This is employed in distribution schemes where "demos" of
the software are provided on a medium along with the entire product. The
demos can be freely used, but in order to use the actual product, the key
must be purchased. These scheme do not hinder copying of the software once
the key is initially purchased.
A system for ensuring that licenses are in place for using licensed
products is described in PCT Publication WO 93/01550 to Griswold entitled
"License Management System and Method." The licensed product may be any
electronically published work but is most effective for use with works
that are used for extended periods of time such as software programs.
Griswold requires that the licensed product contain software to invoke a
license check monitor at predetermined time intervals. The license check
monitor generates request datagrams which identify the licensee. The
request datagrams are sent to a license control system over an appropriate
communication facility. The license control system then checks the
datagram to determine if the datagram is from a valid licensee. The
license control system then sends a reply datagram to the license check
monitor indicating denial or approval of usage. The license control system
will deny usage in the event that request datagrams go unanswered after a
predetermined period of time (which may indicate an unauthorized attempt
to use the licensed product). In this system, usage is managed at a
central location by the response datagrams. So for example if license fees
have not been paid, access to the licensed product is terminated.
It is argued by Griswold that the described system is advantageous because
it can be implemented entirely in software. However, the system described
by Griswold has limitations. An important limitation is that during the
use of the licensed product, the user must always be coupled to an
appropriate communication facility in order to send and receive datagrams.
This creates a dependency on the communication facility. So if the
communication facility is not available, the licensed product cannot be
used. Moreover, some party must absorb the cost of communicating with the
license server.
A system for controlling the distribution of digitally encoded books is
embodied in a system available from VPR Systems, LTD. of St. Louis, Mo.
The VPR system is self-contained and is comprised of: (1) point of sale
kiosks for storing and downloading of books, (2) personal storage mediums
(cartridges) to which the books are downloaded, and (3) readers for
viewing the book. In a purchase transaction, a purchaser will purchase a
voucher card representing the desired book. The voucher will contain
sufficient information to identify the book purchased and perhaps some
demographic information relating to the sales transaction. To download the
book, the voucher and the cartridge are inserted into the kiosk.
The VPR system may also be used as a library. In such an embodiment, the
kiosk manages the number of "copies" that may be checked out at one time.
Further, the copy of the book is erased from the users cartridge after a
certain check-out time has expired. However, individuals cannot loan books
because the cartridges may only be used with the owners reader.
The foregoing distribution and protection schemes operate in part by
preventing subsequent distribution of the work. While this certainly
prevents unauthorized distributions, it does so by sacrificing the
potential for subsequent revenue bearing uses. For example, it may be
desirable to allow the lending of a purchased work to permit exposure of
the work to potential buyers. Another example would be to permit the
creation of a derivative work for a fee. Yet another example would be to
permit copying the work for a fee (essentially purchasing it). Thus, it
would be desirable to provide flexibility in how the owner of a digital
work may allow it to be distributed.
While flexibility in distribution is a concern, the owners of a work want
to make sure they are paid for such distributions. In U.S. Pat. No.
4,977,594 to Shear, entitled "Database Usage Metering and Protection
System and Method," a system for metering and billing for usage of
information distributed on a CD-ROM is described. The system requires the
addition of a billing module to the computer system. The billing module
may operate in a number of different ways. First, it may periodically
communicate billing data to a central billing facility, whereupon the user
may be billed. Second, billing may occur by disconnecting the billing
module and the user sending it to a central billing facility where the
data is read and a user bill generated.
U.S. Pat. No. 5,247,575, Sprague et al., entitled "Information Distribution
System", describes an information distribution system which provides and
charges only for user selected information. A plurality of encrypted
information packages (IPs) are provided at the user site, via high and/or
low density storage media and/or by broadcast transmission. Some of the
IPs may be of no interest to the user. The IPs of interest are selected by
the user and are decrypted and stored locally. The IPs may be printed,
displayed or even copied to other storage medias. The charges for the
selected IP's are accumulated within a user apparatus and periodically
reported by telephone to a central accounting facility. The central
accounting facility also issues keys to decrypt the IPs. The keys are
changed periodically. If the central accounting facility has not issued a
new key for a particular user station, the station is unable to retrieve
information from the system when the key is changed.
A system available from Wave Systems Corp. of Princeton, N.Y., provides for
metering of software usage on a personal computer. The system is installed
onto a computer and collects information on what software is in use,
encrypts it and then transmits the information to a transaction center.
From the transaction center, a bill is generated and sent to the user. The
transaction center also maintains customer accounts so that licensing fees
may be forwarded directly to the software providers. Software operating
under this system must be modified so that usage can be accounted.
Known techniques for billing do not provide for billing of copies made of
the work. For example, if data is copied from the CD-ROM described in
Shear, any subsequent use of the copy of the information cannot be metered
or billed. In other words, the means for billing runs with the media
rather than the underlying work. It would be desirable to have a
distribution system where the means for billing is always transported with
the work.
SUMMARY OF THE INVENTION
A system for controlling the distribution and use of digital works using
digital tickets is disclosed. A ticket is an indicator that the ticket
holder has already paid for or is otherwise entitled to some specified
right, product or service. In the present invention, a "digital ticket" is
used to enable the ticket holder to exercise usage rights specifying the
requirement of the digital ticket. Usage rights are used to define how a
digital work may be used or distributed. Specific instances of usage
rights are used to indicate a particular manner of use or distribution. A
usage right may specify a digital ticket which must be present before the
right may be exercised. For example, a digital ticket may be specified in
a Copy right of a digital work, so that exercise of the Copy right
requires the party that desires a copy of the digital work be in
possession of the necessary digital ticket. After a copy of the digital
work is successfully sent to the requesting party, the digital ticket is
"punched" to indicate that a copy of the digital work has been made. When
the ticket is "punched" a predetermined number of times, it may no longer
be used.
Digital works are stored in repositories. Repositories enforce the usage
rights for digital works. Each repository has a "generic ticket agent"
which punches tickets. In some instances only the generic ticket agent is
necessary. In other instances, punching by a "special ticket agent"
residing on another repository may be desired. Punching by a "special
ticket agent" enables greater security and control of the digital work.
For example, it can help prevent digital ticket forgery. Special ticket
agents are also useful in situations where an external database needs to
be updated or checked.
A digital ticket is merely an instance of a digital work. Thus, a digital
ticket may be distributed among repositories in the same fashion as other
digital works.
A digital ticket may be used in many commercial scenarios such as in the
purchase of software and prepaid upgrades. A digital ticket may also be
used to limit the number of times that a right may be exercised. For
example, a user may purchase a copy of a digital work, along with the
right to make up to 5 Copies. In this case, the Copy right would have
associated therewith a digital ticket that can be punched up to 5 times.
Other such commercial scenarios will become apparent from the detailed
description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart illustrating a simple instantiation of the operation
of the currently preferred embodiment of the present invention.
FIG. 2 is a block diagram illustrating the various repository types and the
repository transaction flow between them in the currently preferred
embodiment of the present invention.
FIG. 3 is a block diagram of a repository coupled with a credit server in
the currently preferred embodiment of the present invention.
FIGS. 4a and 4b are examples of rendering systems as may be utilized in the
currently preferred embodiment of the present invention.
FIG. 5 illustrates a contents file layout for a digital work as may be
utilized in the currently preferred embodiment of the present invention.
FIG. 6 illustrates a contents file layout for an individual digital work of
the digital work of FIG. 5 as may be utilized in the currently preferred
embodiment of the present invention.
FIG. 7 illustrates the components of a description block of the currently
preferred embodiment of the present invention.
FIG. 8 illustrates a description tree for the contents file layout of the
digital work illustrated in FIG. 5.
FIG. 9 illustrates a portion of a description tree corresponding to the
individual digital work illustrated in FIG. 6.
FIG. 10 illustrates a layout for the rights portion of a description block
as may be utilized in the currently preferred embodiment of the present
invention.
FIG. 11 is a description tree wherein certain d-blocks have PRINT usage
rights and is used to illustrate "strict" and "lenient" rules for
resolving usage rights conflicts.
FIG. 12 is a block diagram of the hardware components of a repository as
are utilized in the currently preferred embodiment of the present
invention.
FIG. 13 is a block diagram of the functional (logical) components of a
repository as are utilized in the currently preferred embodiment of the
present invention.
FIG. 14 is diagram illustrating the basic components of a usage right in
the currently preferred embodiment of the present invention.
FIG. 15 lists the usage rights grammar of the currently preferred
embodiment of the present invention.
FIG. 16 is a flowchart illustrating the steps of certificate delivery,
hotlist checking and performance testing as performed in a registration
transaction as may be performed in the currently preferred embodiment of
the present invention.
FIG. 17 is a flowchart illustrating the steps of session information
exchange and clock synchronization as may be performed in the currently
preferred embodiment of the present invention, after each repository in
the registration transaction has successfully completed the steps
described in FIG. 16.
FIG. 18 is a flowchart illustrating the basic flow for a usage transaction,
including the common opening and closing step, as may be performed in the
currently preferred embodiment of the present invention.
FIG. 19 is a state diagram of server and client repositories in accordance
with a transport protocol followed when moving a digital work from the
server to the client repositories, as may be performed in the currently
preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
TABLE OF CONTENTS
OVERVIEW
RENDERING SYSTEMS
STRUCTURE OF DIGITAL WORKS
ATTACHING USAGE RIGHTS TO A DIGITAL WORK
Resolving Conflicitng Rights
REPOSITORIES
Repository Security Classes
Repository User Interface
CREDIT SERVICES
USAGE RIGHTS LANGUAGE
Copy Count Specification
Control Specification
Time Specification
Security Class and Authorization Specification
Usage Fees and Incentives Specification
Examples of Sets of Usage Rights
REPOSITORY TRNASACTIONS
Message Transmission
Session Initiation Transactions
Billing Transactions
Usage Transacitons
Transmission Protocol
The Copy Transaction
The Transfer Transaction
The Loan Transaction
The Play Transaction
The Print Transaction
The Backup Transaction
The Restore Transaction
The Delete Transaction
The Folder Transaction
The Extract Transaction
The Edit Tranaction
The Authorization Transaction
The Install Transaction
The Uninstall Transaction
DISTRIBUTION AND USE SCENARIOS
GLOSSARY
Overview
A system for controlling use and distribution of digital works is
disclosed. The present invention is directed to supporting commercial
transactions involving digital works. The transition to digital works
profoundly and fundamentally changes how creativity and commerce can work.
It changes the cost of transporting or storing works because digital
property is almost "massless." Digital property can be transported at
electronic speeds and requires almost no warehousing. Keeping an unlimited
supply of virtual copies on hand requires essentially no more space than
keeping one copy on hand. The digital medium also lowers the costs of
alteration, reuse and billing.
There is a market for digital works because creators are strongly motivated
to reuse portions of digital works from others rather than creating their
own completely. This is because it is usually so much easier to use an
existing stock photo or music clip than to create a new one from scratch.
Herein the terms "digital work", "work" and "content" refer to any work
that has been reduced to a digital representation. This would include any
audio, video, text, or multimedia work and any accompanying interpreter
(e.g. software) that may be required for recreating the work. The term
composite work refers to a digital work comprised of a collection of other
digital works. The term "usage rights" or "rights" is a term which refers
to rights granted to a recipient of a digital work. Generally, these
rights define how a digital work can be used and if it can be further
distributed. Each usage right may have one or more specified conditions
which must be satisfied before the right may be exercised. A Glossary of
the terms used herein is provided at the end of the specification.
A key feature of the present invention is that usage rights are permanently
"attached" to the digital work. Copies made of a digital work will also
have usage rights attached. Thus, the usage rights and any associated fees
assigned by a creator and subsequent distributor will always remain with a
digital work.
The enforcement elements of the present invention are embodied in
repositories. Among other things, repositories are used to store digital
works, control access to digital works, bill for access to digital works
and maintain the security and integrity of the system.
The combination of attached usage rights and repositories enable distinct
advantages over prior systems. As noted in the prior art, payment of fees
are primarily for the initial access. In such approaches, once a work has
been read, computational control over that copy is gone. Metaphorically,
"the content genie is out of the bottle and no more fees can be billed."
In contrast, the present invention never separates the fee descriptions
from the work. Thus, the digital work genie only moves from one trusted
bottle (repository) to another, and all uses of copies are potentially
controlled and billable.
FIG. 1 is a high level flowchart omitting various details but which
demonstrates the basic operation of the present invention. Referring to
FIG. 1, a creator creates a digital work, step 101. The creator will then
determine appropriate usage rights and fees, attach them to the digital
work, and store them in Repository 1, step 102. The determination of
appropriate usage rights and fees will depend on various economic factors.
The digital work remains securely in Repository 1 until a request for
access is received. The request for access begins with a session
initiation by another repository. Here a Repository 2 initiates a session
with Repository 1, step 103. As will be described in greater detail below,
this session initiation includes steps which helps to insure that the
respective repositories are trustworthy. Assuming that a session can be
established, Repository 2 may then request access to the Digital Work for
a stated purpose, step 104. The purpose may be, for example, to print the
digital work or to obtain a copy of the digital work. The purpose will
correspond to a specific usage right. In any event, Repository 1 checks
the usage rights associated with the digital work to determine if the
access to the digital work may be granted, step 105. The check of the
usage rights essentially involves a determination of whether a right
associated with the access request has been attached to the digital work
and if all conditions associated with the right are satisfied. If the
access is denied, repository 1 terminates the session with an error
message, step 106. If access is granted, repository 1 transmits the
digital work to repository 2, step 107. Once the digital work has been
transmitted to repository 2, repository 1 and 2 each generate billing
information for the access which is transmitted to a credit server, step
108. Such double billing reporting is done to insure against attempts to
circumvent the billing process.
FIG. 2 illustrates the basic interactions between repository types in the
present invention. As will become apparent from FIG. 2, the various
repository types will serve different functions. It is fundamental that
repositories will share a core set of functionality which will enable
secure and trusted communications. Referring to FIG. 2, a repository 201
represents the general instance of a repository. The repository 201 has
two modes of operation; a server mode and a requester mode. When in the
server mode, the repository will be receiving and processing access
requests to digital works. When in the requester mode, the repository will
be initiating requests to access digital works. Repository 201 is general
in the sense that it's primary purpose is as an exchange medium for
digital works. During the course of operation, the repository 201 may
communicate with a plurality of other repositories, namely authorization
repository 202, rendering repository 203 and master repository 204.
Communication between repositories occurs utilizing a repository
transaction protocol 205.
Communication with an authorization repository 202 may occur when a digital
work being accessed has a condition requiring an authorization.
Conceptually, an authorization is a digital certificate such that
possession of the certificate is required to gain access to the digital
work. An authorization is itself a digital work that can be moved between
repositories and subjected to fees and usage rights conditions. An
authorization may be required by both repositories involved in an access
to a digital work.
Communication with a rendering repository 203 occurs in connection with the
rendering of a digital work. As will be described in greater detail below,
a rendering repository is coupled with a rendering device (e.g. a printer
device) to comprise a rendering system.
Communication with a master repository 205 occurs in connection with
obtaining an identification certificate. Identification certificates are
the means by which a repository is identified as "trustworthy". The use of
identification certificates is described below with respect to the
registration transaction.
FIG. 3 illustrates the repository 201 coupled to a credit server 301. The
credit server 301 is a device which accumulates billing information for
the repository 201. The credit server 301 communicates with repository 201
via billing transactions 302 to record billing transactions. Billing
transactions are reported to a billing clearinghouse 303 by the credit
server 301 on a periodic basis. The credit server 301 communicates to the
billing clearinghouse 303 via clearinghouse transactions 304. The
clearinghouse transactions 304 enable a secure and encrypted transmission
of information to the billing clearinghouse 303.
Rendering Systems
A rendering system is generally defined as a system comprising a repository
and a rendering device which can render a digital work into its desired
form. Examples of a rendering system may be a computer system, a digital
audio system, or a printer. A rendering system has the same security
features as a repository. The coupling of a rendering repository with the
rendering device may occur in a manner suitable for the type of rendering
device.
FIG. 4a illustrates a printer as an example of a rendering system.
Referring to FIG. 4, printer system 401 has contained therein a printer
repository 402 and a print device 403. It should be noted that the dashed
line defining printer system 401 defines a secure system boundary.
Communications within the boundary is assumed to be secure. Depending on
the security level, the boundary also represents a barrier intended to
provide physical integrity. The printer repository 402 is an instantiation
of the rendering repository 205 of FIG. 2. The printer repository 402 will
in some instances contain an ephemeral copy of a digital work which
remains until it is printed out by the print engine 403. In other
instances, the printer repository 402 may contain digital works such as
fonts, which will remain and can be billed based on use. This design
assures that all communication lines between printers and printing devices
are encrypted, unless they are within a physically secure boundary. This
design feature eliminates a potential "fault" point through which the
digital work could be improperly obtained. The printer device 403
represents the printer components used to create the printed output.
Also illustrated in FIG. 4a is the repository 404. The repository 404 is
coupled to the printer repository 402. The repository 404 represents an
external repository which contains digital works.
FIG. 4b is an example of a computer system as a rendering system. A
computer system may constitute a "multi-function" device since it may
execute digital works (e.g. software programs) and display digital works
(e.g. a digitized photograph). Logically, each rendering device can be
viewed as having it's own repository, although only one physical
repository is needed. Referring to FIG. 4b, a computer system 410 has
contained therein a display/execution repository 411. The
display/execution repository 411 is coupled to display device, 412 and
execution device 413. The dashed box surrounding the computer system 410
represents a security boundary within which communications are assumed to
be secure. The display/execution repository 411 is further coupled to a
credit server 414 to report any fees to be billed for access to a digital
work and a repository 415 for accessing digital works stored therein.
Structure of Digital Works
Usage rights are attached directly to digital works. Thus, it is important
to understand the structure of a digital work. The structure of a digital
work, in particular composite digital works, may be naturally organized
into an acyclic structure such as a hierarchy. For example, a magazine has
various articles and photographs which may have been created and are owned
by different persons. Each of the articles and photographs may represent a
node in a hierarchical structure. Consequently, controls, i.e. usage
rights, may be placed on each node by the creator. By enabling control and
fee billing to be associated with each node, a creator of a work can be
assured that the rights and fees are not circumvented.
In the currently preferred embodiment, the file information for a digital
work is divided into two files: a "contents" file and a "description tree"
file. From the perspective of a repository, the "contents" file is a
stream of addressable bytes whose format depends completely on the
interpreter used to play, display or print the digital work. The
description tree file makes it possible to examine the rights and fees for
a work without reference to the content of the digital work. It should be
noted that the term description tree as used herein refers to any type of
acyclic structure used to represent the relationship between the various
components of a digital work.
FIG. 5 illustrates the layout of a contents file. Referring to FIG. 5, a
digital work 509 is comprised of story A 510, advertisement 511, story B
512 and story C 513. It is assumed that the digital work is stored
starting at a relative address of 0. Each of the parts of the digital work
are stored linearly so that story A 510 is stored at approximately
addresses 0-30,000, advertisement 511 at addresses 30,001-40,000, story B
512 at addresses 40,001-60,000 and story C 513 at addresses 60,001-85 K.
The detail of story A 510 is illustrated in FIG. 6. Referring to FIG. 6,
the story A 510 is further broken down to show text 614 stored at address
0-1500, soldier photo 615 at addresses 1501-10,000, graphics 616 stored at
addresses 10,001-25,000 and sidebar 617 stored address 25,001-30,000. Note
that the data in the contents file may be compressed (for saving storage)
or encrypted (for security).
From FIGS. 5 and 6 it is readily observed that a digital work can be
represented by its component parts as a hierarchy. The description tree
for a digital work is comprised of a set of related descriptor blocks
(d-blocks). The contents of each d-block is described with respect to FIG.
7. Referring to FIG. 7, a d-block 700 includes an identifier 701 which is
a unique identifier for the work in the repository, a starting address 702
providing the start address of the first byte of the work, a length 703
giving the number of bytes in the work, a rights portion 704 wherein the
granted usage rights and their status data are maintained, a parent
pointer 705 for pointing to a parent d-block and child pointers 706 for
pointing to the child d-blocks. In the currently preferred embodiment, the
identifier 701 has two parts. The first part is a unique number assigned
to the repository upon manufacture. The second part is a unique number
assigned to the work upon creation. The rights portion 704 will contain a
data structure, such as a look-up table, wherein the various information
associated with a right is maintained. The information required by the
respective usage rights is described in more detail below. D-blocks form a
strict hierarchy. The top d-block of a work has no parent; all other
d-blocks have one parent. The relationship of usage rights between parent
and child d-blocks and how conflicts are resolved is described below.
A special type of d-block is a "shell" d-block. A shell d-block adds no new
content beyond the content of its parts. A shell d-block is used to add
rights and fee information, typically by distributors of digital works.
FIG. 8 illustrates a description tree for the digital work of FIG. 5.
Referring to FIG. 8, a top d-block 820 for the digital work points to the
various stories and advertisements contained therein. Here, the top
d-block 820 points to d-block 821 (representing story A 510), d-block 822
(representing the advertisement 511), d-block 823 (representing story B
512) and and d-block 824 (representing story C 513).
The portion of the description tree for Story A 510 is illustrated in FIG.
9. D-block 925 represents text 614, d-block 926 represents photo 615,
d-block 927 represents graphics 616 by and d-block 928 represents sidebar
617.
The rights portion 704 of a descriptor block is further illustrated in FIG.
10. FIG. 10 illustrates a structure which is repeated in the rights
portion 704 for each right. Referring to FIG. 10, each right will have a
right code field 1001 and status information field 1002. The right code
field 1001 will contain a unique code assigned to a right. The status
information field 1002 will contain information relating to the state of a
right and the digital work. Such information is indicated below in Table
1. The rights as stored in the rights portion 304 may typically be in
numerical order based on the right code.
The approach for representing digital works by separating description data
from content assumes that parts of a file are contiguous but takes no
position on the actual representation of content. In particular, it is
neutral to the question of whether content representation may take an
object oriented approach. It would be natural to represent content as
objects. In principle, it may be convenient to have content objects that
include the billing structure and rights information that is represented
in the d-blocks. Such variations in the design of the representation are
possible and are
TABLE 1
DIGITAL WORK STATE INFORMATION
Property Value Use
Copies -in- Number A counter of the number of copies of a
Use work that are in use. Incremented when
another copy is used; decremented when
use is completed.
Loan-Period Time-Units Indicator of the maximum number of
time-units that a document can be
loaned out
Loaner-Copy Boolean Indicator that the current work is a
loaned out copy of an authorized digital
work.
Remaining- Time-Units Indicator of the remaining time of use
Time on a metered document right.
Document- String A string containing various identifying
Descr information about a document. The
exact format of this is not specified, but
it can include information such as a
publisher name, author name, ISBN
number, and so on.
Revenue- RO-Descr A handle identifying a revenue owner
Owner for a digital work. This is used for
reporting usage fees.
Publication- Date-Descr The date that the digital work was
Date published.
History-list History-Rec A list of events recording the repositories
and dates for operations that copy,
transfer, backup, or restore a digital
work.
viable alternatives but may introduce processing overhead, e.g. the
interpretation of the objects.
Digital works are stored in a repository as part of a hierarchical file
system. Folders (also termed directories and sub-directories) contain the
digital works as well as other folders. Digital works and folders in a
folder are ordered in alphabetical order. The digital works are typed to
reflect how the files are used. Usage rights can be attached to folders so
that the folder itself is treated as a digital work. Access to the folder
would then be handled in the same fashion as any other digital work As
will be described in more detail below, the contents of the folder are
subject to their own rights. Moreover, file management rights may be
attached to the folder which define how folder contents can be managed.
Attaching Usage Rights to a Digital Work
It is fundamental to the present invention that the usage rights are
treated as part of the digital work. As the digital work is distributed,
the scope of the granted usage rights will remain the same or may be
narrowed. For example, when a digital work is transferred from a document
server to a repository, the usage rights may include the right to loan a
copy for a predetermined period of time (called the original rights). When
the repository loans out a copy of the digital work, the usage rights in
the loaner copy (called the next set of rights) could be set to prohibit
any further rights to loan out the copy. The basic idea is that one cannot
grant more rights than they have.
The attachment of usage rights into a digital work may occur in a variety
of ways. If the usage rights will be the same for an entire digital work,
they could be attached when the digital work is processed for deposit in
the digital work server. In the case of a digital work having different
usage rights for the various components, this can be done as the digital
work is being created. An authoring tool or digital work assembling tool
could be utilized which provides for an automated process of attaching the
usage rights.
As will be described below, when a digital work is copied, transferred or
loaned, a "next set of rights" can be specified. The"next set of rights"
will be attached to the digital work as it is transported.
Resolving Conflicting Rights
Because each part of a digital work may have its own usage rights, there
will be instances where the rights of a "contained part" are different
from its parent or container part. As a result, conflict rules must be
established to dictate when and how a right may be exercised. The
hierarchical structure of a digital work facilitates the enforcement of
such rules. A "strict" rule would be as follows: a right for a part in a
digital work is sanctioned if and only if it is sanctioned for the part,
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