U.S. patent application number 13/175624 was filed with the patent office on 2012-01-05 for system and method for rendering content associated with a digital work.
This patent application is currently assigned to ContentGuard Holdings, Inc.. Invention is credited to Peter L.T. Pirolli, Mark J. Stefik.
Application Number | 20120005760 13/175624 |
Document ID | / |
Family ID | 23351914 |
Filed Date | 2012-01-05 |
United States Patent
Application |
20120005760 |
Kind Code |
A1 |
Stefik; Mark J. ; et
al. |
January 5, 2012 |
SYSTEM AND METHOD FOR RENDERING CONTENT ASSOCIATED WITH A DIGITAL
WORK
Abstract
A method, system and software for permitting use of digital
works having rights associated therewith in a system having
repositories configured to enable use of the digital work in
accordance with the rights, including associating a transfer right
with a digital work, the transfer right specifying that the digital
work is transferred from a first repository to a second repository;
transferring the digital work from the first repository to the
second repository in accordance with the transfer right; and in
response to the transferring, step updating transfer right
information in respect of the digital work.
Inventors: |
Stefik; Mark J.; (Portola
Valley, CA) ; Pirolli; Peter L.T.; (San Francisco,
CA) |
Assignee: |
ContentGuard Holdings, Inc.
Wilmington
DE
|
Family ID: |
23351914 |
Appl. No.: |
13/175624 |
Filed: |
July 1, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12771527 |
Apr 30, 2010 |
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13175624 |
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11401925 |
Apr 12, 2006 |
7788182 |
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12771527 |
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10463761 |
Jun 18, 2003 |
7058606 |
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11401925 |
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09778001 |
Feb 7, 2001 |
6708157 |
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10463761 |
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08967084 |
Nov 10, 1997 |
6236971 |
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09778001 |
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08344760 |
Nov 23, 1994 |
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08967084 |
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Current U.S.
Class: |
726/27 |
Current CPC
Class: |
H04N 21/8355 20130101;
H04L 63/123 20130101; Y10S 707/99945 20130101; G06Q 30/0283
20130101; H04N 21/6332 20130101; G06Q 20/3674 20130101; H04L
2463/101 20130101; H04N 21/26613 20130101; G06F 2211/007 20130101;
H04N 7/16 20130101; H04L 9/3297 20130101; H04L 12/1485 20130101;
H04N 21/835 20130101; G06F 2221/2115 20130101; G06Q 30/0601
20130101; H04N 21/23412 20130101; G06F 21/10 20130101; H04L 12/14
20130101; H04L 63/104 20130101; H04N 21/2541 20130101; H04N 21/4627
20130101; H04L 12/1403 20130101; H04L 29/06 20130101; H04N 21/6377
20130101; G06Q 10/101 20130101; H04L 2209/56 20130101; G06Q 30/00
20130101; H04L 61/15 20130101; H04L 2209/603 20130101; H04N 21/2543
20130101; G06Q 20/12 20130101; G06Q 30/06 20130101; H04L 63/0807
20130101; H04L 9/3213 20130101; H04L 63/10 20130101; H04L 63/0428
20130101; H04L 63/0442 20130101; H04L 63/0823 20130101; G06Q 30/02
20130101; G06Q 30/04 20130101; G06Q 50/184 20130101; H04L 12/146
20130101; H04L 63/0464 20130101; G06F 2221/2135 20130101; Y10S
707/99939 20130101; H04L 12/1496 20130101; G06Q 30/0185 20130101;
H04L 29/12009 20130101; H04L 63/102 20130101; H04N 21/83555
20130101; H04L 29/12047 20130101; H04L 63/105 20130101; G06Q
20/1235 20130101 |
Class at
Publication: |
726/27 |
International
Class: |
G06F 21/24 20060101
G06F021/24 |
Claims
1. A method for controlling rendering of digital content, the
method comprising: storing the digital content in a storage,
wherein the digital content is associated with a usage right;
receiving, from a means for requesting, a request for rendering of
the digital content; and processing, by a repository, the request
to make the digital content available to a rendering engine for
rendering if the rendering is permitted by the usage right.
2. An apparatus for rendering digital content, the apparatus
comprising: a rendering engine configured to render digital
content, wherein the digital content is associated with a usage
right; a storage for storing the digital content; means for
requesting use of the stored digital content; and a repository
configured to process the request to make the digital content
available to the rendering engine for rendering if the rendering is
permitted by the usage right.
3. Computer-executable code stored on a non-transitory
computer-readable medium that, when executed by a mobile device,
performs a method for controlling rendering of digital content, the
method comprising: storing the digital content in a storage,
wherein the digital content is associated with a usage right;
receiving, from a means for requesting, a request for rendering of
the digital content; and processing, by a repository, the request
to make the digital content available to a rendering engine for
rendering if the rendering is permitted by the usage right.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/771,527, filed Apr. 30, 2010, which is a
continuation of U.S. patent application Ser. No. 11/401,925, filed
Apr. 12, 2006, now U.S. Pat. No. 7,788,182, which is a divisional
of U.S. patent application Ser. No. 10/463,761, filed on Jun. 18,
2003, now U.S. Pat. No. 7,058,606, which is a continuation of U.S.
patent application Ser. No. 09/778,001, filed on Feb. 7, 2001, now
U.S. Pat. No. 6,708,157, which is a divisional of U.S. patent
application Ser. No. 08/967,084, filed on Nov. 10, 1997, now U.S.
Pat. No. 6,236,971, which is a continuation of U.S. patent
application Ser. No. 08/344,760, filed on Nov. 23, 1994, now
abandoned, the disclosures of all of which are hereby incorporated
by reference herein.
FIELD OF THE INVENTION
[0002] The present invention relates to the field of distribution
and usage rights enforcement for digitally encoded works.
BACKGROUND OF THE INVENTION
[0003] 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.)
[0004] 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.
[0005] 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.
[0006] Yet another scheme is to distribute software, but which
requires a "key" to enable its 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 schemes do not hinder copying of the software once
the key is initially purchased.
[0007] 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.
[0008] 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.
[0009] A system for controlling the distribution of digitally
encoded books is embodied in a system available from VPR Systems,
LTD. of St. Louis, Miss. 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.
[0010] 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 user's cartridge after a certain check-out time has
expired. However, individuals cannot loan books because the
cartridges may only be used with the owner's reader.
[0011] 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.
[0012] 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.
[0013] 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. media. 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.
[0014] 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.
[0015] 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
[0016] 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.
[0017] 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.
[0018] 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.
[0019] 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
[0020] FIG. 1 is a flowchart illustrating a simple instantiation of
the operation of the currently preferred embodiment of the present
invention.
[0021] 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.
[0022] FIG. 3 is a block diagram of a repository coupled with a
credit server in the currently preferred embodiment of the present
invention.
[0023] FIGS. 4a and 4b are examples of rendering systems as may be
utilized in the currently preferred embodiment of the present
invention.
[0024] FIG. 5 illustrates a contents file layout for a digital work
as may be utilized in the currently preferred embodiment of the
present invention.
[0025] 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.
[0026] FIG. 7 illustrates the components of a description block of
the currently preferred embodiment of the present invention.
[0027] FIG. 8 illustrates a description tree for the contents file
layout of the digital work illustrated in FIG. 5.
[0028] FIG. 9 illustrates a portion of a description tree
corresponding to the individual digital work illustrated in FIG.
6.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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.
[0033] FIG. 14 is diagram illustrating the basic components of a
usage right in the currently preferred embodiment of the present
invention.
[0034] FIG. 15 lists the usage rights grammar of the currently
preferred embodiment of the present invention.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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
Overview
[0039] 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.
[0040] 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.
[0041] 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. Appendix 1 provides a Glossary of the terms used
herein.
[0042] 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.
[0043] 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.
[0044] 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.
[0045] 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
help 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.
[0046] 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 its 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.
[0047] 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.
[0048] 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.
[0049] 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.
[0050] 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
[0051] 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.
[0052] 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.
[0053] 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.
[0054] 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 its 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
[0055] 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.
[0056] 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.
[0057] 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 60,001-85K.
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).
[0058] 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
are 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.
[0059] 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.
[0060] 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
d-block 824 (representing story C 513).
[0061] 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.
[0062] 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.
[0063] 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 viable alternatives but may introduce processing
overhead, e.g. the interpretation of the objects.
TABLE-US-00001 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 repostories and dates for operations that
copy, transfer, backup, or restore a digital work.
[0064] 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 defines how folder
contents can be managed.
Attaching Usage Rights to a Digital Work
[0065] 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.
[0066] 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.
[0067] 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
[0068] 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, for ancestor d-blocks
containing the part and for all descendent d-blocks. By sanctioned,
it is meant that (1) each of the respective parts must have the
right, and (2) any conditions for exercising the right are
satisfied.
[0069] It also possible to implement the present invention using a
more lenient rule. In the more lenient rule, access to the part may
be enabled to the descendent parts which have the right, but access
is denied to the descendents which do not.
[0070] Example of applying both the strict rule and lenient is
illustrated with reference to FIG. 11. Referring to FIG. 11, a root
d-block 1101 has child d-blocks 1102-1105. In this case, root
d-block represents a magazine, and each of the child d-blocks
1102-1105 represent articles in the magazine. Suppose that a
request is made to PRINT the digital work represented by root
d-block 1101 wherein the strict rule is followed. The rights for
the root d-block 1101 and child d-blocks 1102-1105 are then
examined. Root d-block 1101 and child d-blocks 1102 and 1105 have
been granted PRINT rights. Child d-block 1103 has not been granted
PRINT rights and child d-block 1104 has PRINT rights conditioned on
payment of a usage fee.
[0071] Under the strict rule the PRINT right cannot be exercised
because the child d-block does not have the PRINT right. Under the
lenient rule, the result would be different. The digital works
represented by child d-blocks 1102 and 1105 could be printed and
the digital work represented by d-block 1104 could be printed so
long as the usage fee is paid. Only the digital work represented by
d-block 1103 could not be printed. This same result would be
accomplished under the strict rule if the requests were directed to
each of the individual digital works.
[0072] The present invention supports various combinations of
allowing and disallowing access. Moreover, as will be described
below, the usage rights grammar permits the owner of a digital work
to specify if constraints may be imposed on the work by a container
part. The manner in which digital works may be sanctioned because
of usage rights conflicts would be implementation specific and
would depend on the nature of the digital works.
Repositories
[0073] Many of the powerful functions of repositories--such as
their ability to "loan" digital works or automatically handle the
commercial reuse of digital works--are possible because they are
trusted systems. The systems are trusted because they are able to
take responsibility for fairly and reliably carrying out the
commercial transactions. That the systems can be responsible ("able
to respond") is fundamentally an issue of integrity. The integrity
of repositories has three parts: physical integrity, communications
integrity, and behavioral integrity.
[0074] Physical integrity refers to the integrity of the physical
devices themselves. Physical integrity applies both to the
repositories and to the protected digital works. Thus, the higher
security classes of repositories themselves may have sensors that
detect when tampering is attempted on their secure cases. In
addition to protection of the repository itself, the repository
design protects access to the content of digital works. In contrast
with the design of conventional magnetic and optical devices--such
as floppy disks, CD-ROMs, and videotapes--repositories never allow
non-trusted systems to, access the works directly. A maker of
generic computer systems cannot guarantee that their platform will
not be used to make unauthorized copies. The manufacturer provides
generic capabilities for reading and writing information, and the
general nature of the functionality of the general computing device
depends on it. Thus, a copy program can copy arbitrary data. This
copying issue is not limited to general purpose computers. It also
arises for the unauthorized duplication of entertainment "software"
such as video and audio recordings by magnetic recorders. Again,
the functionality of the recorders depends on their ability to copy
and they have no means to check whether a copy is authorized. In
contrast, repositories prevent access to the raw data by general
devices and can test explicit rights and conditions before copying
or otherwise granting access. Information is only accessed by
protocol between trusted repositories.
[0075] Communications integrity refers to the integrity of the
communications channels between repositories. Roughly speaking,
communications integrity means that repositories cannot be easily
fooled by "telling them lies." Integrity in this case refers to the
property that repositories will only communicate with other devices
that are able to present proof that they are certified
repositories, and furthermore, that the repositories monitor the
communications to detect "impostors" and malicious or accidental
interference. Thus the security measures involving encryption,
exchange of digital certificates, and nonces described below are
all security measures aimed at reliable communication in a world
known to contain active adversaries.
[0076] Behavioral integrity refers to the integrity in what
repositories do. What repositories do is determined by the software
that they execute. The integrity of the software is generally
assured only by knowledge of its source. Restated, a user will
trust software purchased at a reputable computer store but not
trust software obtained off a random (insecure) server on a
network. Behavioral integrity is maintained by requiring that
repository software be certified and be distributed with proof of
such certification, i.e. a digital certificate. The purpose of the
certificate is to authenticate that the software has been tested by
an authorized organization, which attests that the software does
what it is supposed to do and that it does not compromise the
behavioral integrity of a repository. If the digital certificate
cannot be found in the digital work or the master repository which
generated the certificate is not known to the repository receiving
the software, then the software cannot be installed.
[0077] In the description of FIG. 2, it was indicated that
repositories come in various forms. All repositories provide a core
set of services for the transmission of digital works. The manner
in which digital works are exchanged is the basis for all
transaction between repositories. The various repository types
differ in the ultimate functions that they perform. Repositories
may be devices themselves, or they may be incorporated into other
systems. An example is the rendering repository 205 of FIG. 2.
[0078] A repository will have associated with it a repository
identifier. Typically, the repository identifier would be a unique
number assigned to the repository at the time of manufacture. Each
repository will also be classified as being in a particular
security class. Certain communications and transactions may be
conditioned on. a repository being in a particular security class.
The various security classes are described in greater detail
below.
[0079] As a prerequisite to operation, a repository will require
possession of an identification certificate. Identification
certificates are encrypted to prevent forgery and are issued by a
Master repository. A master repository plays the role of an
authorization agent to enable repositories to receive digital
works. Identification certificates must be updated on a periodic
basis. Identification certificates are described in greater detail
below with respect to the registration transaction.
[0080] A repository has both a hardware and functional embodiment.
The functional embodiment is typically software executing on the
hardware embodiment. Alternatively, the functional embodiment may
be embedded in the hardware embodiment such as an Application
Specific Integrated Circuit (ASIC) chip.
[0081] The hardware embodiment of a repository will be enclosed in
a secure housing which if compromised, may cause the repository to
be disabled. The basic components of the hardware embodiment of a
repository are described with reference to FIG. 12. Referring to
FIG. 12, a repository is comprised of a processing means 1200,
storage system 1207, clock 1205 and external interface 1206. The
processing means 1200 is comprised of a processor element 1201 and
processor memory 1202. The processing means 1201 provides
controller, repository transaction and usage rights transaction
functions for the repository. Various functions in the operation of
the repository such as decryption and/or decompression of digital
works and transaction messages are also performed by the processing
means 1200. The processor element 1201 may be a microprocessor or
other suitable computing component. The processor memory 1202 would
typically be further comprised of Read Only Memories (ROM) and
Random Access Memories (RAM). Such memories would contain the
software instructions utilized by the processor element 1201 in
performing the functions of the repository.
[0082] The storage system 1207 is further comprised of descriptor
storage 1203 and content storage 1204. The description tree storage
1203 will store the description tree for the digital work and the
content storage will store the associated content. The description
tree storage 1203 and content storage 1204 need not be of the same
type of storage medium, nor are they necessarily on the same
physical device. So for example, the descriptor storage 1203 may be
stored on a solid state storage (for rapid retrieval of the
description tree information), while the content storage 1204 may
be on a high capacity storage such as an optical disk.
[0083] The clock 1205 is used to time-stamp various time based
conditions for usage rights or for metering usage fees which may be
associated with the digital works. The clock 1205 will have an
uninterruptible power supply, e.g. a battery, in order to maintain
the integrity of the time-stamps. The external interface means 1206
provides for the signal connection to other repositories and to a
credit server. The external interface means 1206 provides for the
exchange of signals via such standard interfaces such as RS-232 or
Personal Computer Manufacturers Card Industry Association (PCMCIA)
standards, or FDDI. The external interface means 1206 may also
provide network connectivity.
[0084] The functional embodiment of a repository is described with
reference to FIG. 13. Referring to FIG. 13, the functional
embodiment is comprised of an operating system 1301, core
repository services 1302, usage transaction handlers 1303,
repository specific functions, 1304 and a user interface 1305. The
operating system 1301 is specific to the repository and would
typically depend on the type of processor being used. The operating
system 1301 would also provide the basic services for controlling
and interfacing between the basic components of the repository.
[0085] The core repository services 1302 comprise a set of
functions required by each and every repository. The core
repository services 1302 include the session initiation
transactions which are defined in greater detail below. This set of
services also includes a generic ticket agent which is used to
"punch" a digital ticket and a generic authorization server for
processing authorization specifications. Digital tickets and
authorizations are specific mechanisms for controlling the
distribution and use of digital works and are described and more
detail below. Note that coupled to the core repository services are
a plurality of identification certificates 1306. The identification
certificates 1306 are required to enable the use of the
repository.
[0086] The usage transactions handler 1303 comprise functionality
for processing access requests to digital works and for billing
fees based on access. The usage transactions supported will be
different for each repository type. For example, it may not be
necessary for some repositories to handle access requests for
digital works.
[0087] The repository specific functionality 1304 comprises
functionality that is unique to a repository. For example, the
master repository has special functionality for issuing digital
certificates and maintaining encryption keys. The repository
specific functionality 1304 would include the user interface
implementation for the repository.
Repository Security Classes
[0088] For some digital works the losses caused by any individual
instance of unauthorized copying is insignificant and the chief
economic concern lies in assuring the convenience of access and
low-overhead billing. In such cases, simple and inexpensive
handheld repositories and network-based workstations may be
suitable repositories, even though the measures and guarantees of
security are modest.
[0089] At the other extreme, some digital works such as a digital
copy of a first run movie or a bearer bond or stock certificate
would be of very high value so that it is prudent to employ caution
and fairly elaborate security measures to ensure that they are not
copied or forged. A repository suitable for holding such a digital
work could have elaborate measures for ensuring physical integrity
and for verifying authorization before use.
[0090] By arranging a universal protocol, all kinds of repositories
can communicate with each other in principle. However, creators of
some works will want to specify that their works will only be
transferred to repositories whose level of security is high enough.
For this reason, document repositories have a ranking system for
classes and levels of security. The security classes in the
currently preferred embodiment are described in Table 2.
TABLE-US-00002 TABLE 2 REPOSITORY SECURITY LEVELS Level Description
of Security 0 Open system. Document transmission is unencrypted. No
digital certificate is required for identification. The security of
the system depends mostly on user honesty, since only modest
knowledge may be needed to circumvent the security measures. The
repository has no provisions for preventing unauthorized programs
from running and accessing or copying files. The system does not
prevent the use of removable storage and does not encrypt stored
files. 1 Minimal security. Like the previous class except that
stored files are minimally encrypted, including ones on removable
storage. 2 Basic security. Like the previous class except that
special tools and knowledge are required to compromise the
programming, the contents of the repository, or the state of the
clock. All digital communications are encrypted. A digital
certificate is provided as identification. Medium level encryption
is used. Repository identification number is unforgeable. 3 General
security. Like the previous class plus the requirement of special
tools are needed to compromise the physical integrity of the
repository and that modest encryption is used on all transmissions.
Password protection is required to use the local user interface.
The digital clock system cannot be reset without authorization. No
works would be stored on removable storage. When executing works as
programs, it runs them in their own address space and does not give
them direct access to any file storage or other memory containing
system code or works. They can access works only through the
transmission transaction protocol. 4 Like the previous class except
that high level encryption is used on all communications. Sensors
are used to record attempts at physical and electronic tampering.
After such tampering, the repository will not perform other
transactions until it has reported such tampering to a designated
server. 5 Like the previous class except that if the physical or
digital attempts at tampering exceed some preset thresholds that
threaten the physical integrity of the repository or the integrity
of digital and cryptographic barriers, then the repository will
save only document description records of history but will erase or
destroy any digital identifiers that could be misused if released
to an unscrupulous party. It also modifies any certificates of
authenticity to indicate that the physical system has been
compromised. It also erases the contents of designated documents. 6
Like the previous class except that the repository will attempt
wireless communication to report tampering and will employ noisy
alarms. 10 This would correspond to a very high level of security.
This server would maintain constant communications to remote
security systems reporting transactions, sensor readings, and
attempts to circumvent security.
[0091] The characterization of security levels described in Table 2
is not intended to be fixed. More important is the idea of having
different security levels for different repositories. It is
anticipated that new security classes and requirements will evolve
according to social situations and changes in technology.
Repository User Interface
[0092] A user interface is broadly defined as the mechanism by
which a user interacts with a repository in order to invoke
transactions to gain access to a digital work, or exercise usage
rights. As described above, a repository may be embodied in various
forms. The user interface for a repository will differ depending on
the particular embodiment. The user interface may be a graphical
user interface having icons representing the digital works and the
various transactions that may be performed. The user interface may
be a generated dialog in which a user is prompted for
information.
[0093] The user interface itself need not be part of the
repository. As a repository may be embedded in some other device,
the user interface may merely be a part of the device in which the
repository is embedded. For example, the repository could be
embedded in a "card" that is inserted into an available slot in a
computer system. The user interface may be combination of a
display, keyboard, cursor control device and software executing on
the computer system.
[0094] At a minimum, the user interface must permit a user to input
information such as access requests and alpha numeric data and
provide feedback as to transaction status. The user interface will
then cause the repository to initiate the suitable transactions to
service the request. Other facets of a particular user interface
will depend on the functionality that a repository will
provide.
Credit Servers
[0095] In the present invention, fees may be associated with the
exercise of a right. The requirement for payment of fees is
described with each version of a usage right in the usage rights
language. The recording and reporting of such fees is performed by
the credit server. One of the capabilities enabled by associating
fees with rights is the possibility of supporting a wide range of
charging models. The simplest model, used by conventional software,
is that there is a single fee at the time of purchase, after which
the purchaser obtains unlimited rights to use the work as often and
for as long as he or she wants. Alternative models, include metered
use and variable fees. A single work can have different fees for
different uses. For example, viewing a photograph on a display
could have different fees than making a hardcopy or including it in
a newly created work. A key to these alternative charging models is
to have a low overhead means of establishing fees and accounting
for credit on these transactions.
[0096] A credit server is a computational system that reliably
authorizes and records these transactions so that fees are billed
and paid. The credit server reports fees to a billing
clearinghouse. The billing clearinghouse manages the financial
transactions as they occur. As a result, bills may be generated and
accounts reconciled. Preferably, the credit server would store the
fee transactions and periodically communicate via a network with
billing clearinghouse for reconciliation. In such an embodiment,
communications with the billing clearinghouse would be encrypted
for integrity and security reasons. In another embodiment, the
credit server acts as a "debit card" where transactions occur in
"real-time" against a user account.
[0097] A credit server is comprised of memory, a processing means,
a clock, and interface means for coupling to a repository and a
financial institution (e.g. a modem). The credit server will also
need to have security and authentication functionality. These
elements are essentially the same elements as those of a
repository. Thus, a single device can be both a repository and a
credit server, provided that it has the appropriate processing
elements for carrying out the corresponding functions and
protocols. Typically, however, a credit server would be a
card-sized system in the possession of the owner of the credit. The
credit server is coupled to a repository and would interact via
financial transactions as described below. Interactions with a
financial institution may occur via protocols established by the
financial institutions themselves.
[0098] In the currently preferred embodiment credit servers
associated with both the server and the repository report the
financial transaction to the billing clearinghouse. For example,
when a digital work is copied by one repository to another for a
fee, credit servers coupled to each of the repositories will report
the transaction to the billing clearinghouse. This is desirable in
that it insures that a transaction will be accounted for in the
event of some break in the communication between a credit server
and the billing clearinghouse. However, some implementations may
embody only a single credit server reporting the transaction to
minimize transaction processing at the risk of losing some
transactions.
Usage Rights Language
[0099] The present invention uses statements in a high level "usage
rights language" to define rights associated with digital works and
their parts. Usage rights statements are interpreted by
repositories and are used to determine what transactions can be
successfully carried out for a digital work and also to determine
parameters for those transactions. For example, sentences in the
language determine whether a given digital work can be copied, when
and how it can be used, and what fees (if any) are to be charged
for that use. Once the usage rights statements are generated, they
are encoded in a suitable form for accessing during the processing
of transactions.
[0100] Defining usage rights in terms of a language in combination
with the hierarchical representation of a digital work enables the
support of a wide variety of distribution and fee schemes. An
example is the ability to attach multiple versions of a right to a
work. So a creator may attach a PRINT right to make 5 copies for
$10.00 and a PRINT right to make unlimited copies for $100.00. A
purchaser may then choose which option best fits his needs. Another
example is that rights and fees are additive. So in the case of a
composite work, the rights and fees of each of the components works
is used in determining the rights and fees for the work as a whole.
Other features and benefits of the usage rights language will
become apparent in the description of distribution and use
scenarios provided below.
[0101] The basic contents of a right are illustrated in FIG. 14.
Referring to FIG. 14, a right 1450 has a transactional component
1451 and a specifications component 1452. A right 1450 has a label
(e.g. COPY or PRINT) which indicate the use or distribution
privileges that are embodied by the right. The transactional
component 1451 corresponds to a particular way in which a digital
work may be used or distributed. The transactional component 1451
is typically embodied in software instructions in a repository
which implement the use or distribution privileges for the right.
The specifications components 1452 are used to specify conditions
which must be satisfied prior to the right being exercised or to
designate various transaction related parameters. In the currently
preferred embodiment, these specifications include copy count 1453,
Fees and Incentives 1454, Time 1455, Access and Security 1456 and
Control 1457. Each of these specifications will be described in
greater detail below with respect to the language grammar
elements.
[0102] The usage rights language is based on the grammar described
below. A grammar is a convenient means for defining valid sequence
of symbols for a language. In describing the grammar the notation
"[a|b|c]" is used to indicate distinct choices among alternatives.
In this example, a sentence can have either an "a", "b" or "c". It
must include exactly one of them. The braces { } are used to
indicate optional items. Note that brackets, bars and braces are
used to describe the language of usage rights sentences but do not
appear in actual sentences in the language.
[0103] In contrast, parentheses are part of the usage rights
language. Parentheses are used to group items together in lists.
The notation (x*) is used to indicate a variable length list, that
is, a list containing one or more items of type x. The notation
(x)* is used to indicate a variable number of lists containing
x.
[0104] Keywords in the grammar are words followed by colons.
Keywords are a common and very special case in the language. They
are often used to indicate a single value, typically an identifier.
In many cases, the keyword and the parameter are entirely optional.
When a keyword is given, it often takes a single identifier as its
value. In some cases, the keyword takes a list of identifiers.
[0105] In the usage rights language, time is specified in an
hours:minutes:seconds (or hh:mm:ss) representation. Time zone
indicators, e.g. PDT for Pacific Daylight Time, may also be
specified. Dates are represented as year/month/day (or
YYYY/MMM/DD). Note that these time and date representations may
specify moments in time or units of time Money units are specified
in terms of dollars.
[0106] Finally, in the usage rights language, various "things" will
need to interact with each other. For example, an instance of a
usage right may specify a bank account, a digital ticket, etc. Such
things need to be identified and are specified herein using the
suffix "-ID.".
[0107] The Usage Rights Grammar is listed in it's entirety in FIG.
15 and is described below.
[0108] Grammar element 1501 "Digital Work Rights:=(Rights*)" define
the digital work rights as a set of rights. The-set of rights
attached to a digital work define how that digital work may be
transferred, used, performed or played. A set of rights will attach
to the entire digital work and in the case of compound digital
works, each of the components of the digital work. The usage rights
of components of a digital may be different.
[0109] Grammar element 1502 "Right:=(Right-Code {Copy-Count}
{Control-Spec} {Time-Spec} {Access-Spec} {Fee-Spec})" enumerates
the content of a right. Each usage right must specify a right code.
Each right may also optionally specify conditions which must be
satisfied before the right can be exercised. These conditions are
copy count, control, time, access and fee conditions. In the
currently preferred embodiment, for the optional elements, the
following defaults apply: copy count equals 1, no time limit on the
use of the right, no access tests or a security level required to
use the right and no fee is required. These conditions will each be
described in greater detail below.
[0110] It is important to note that a digital work may have
multiple versions of a right, each having the same right code. The
multiple versions would provide alternative conditions and fees for
accessing the digital work.
[0111] A Grammar element 1503
"Right-Code:=Render-Code|Transport--Code|File-Management-Code|Derivative--
Works-Code Configuration-Code" distinguishes each of the specific
rights into a particular right type (although each right is
identified by distinct right codes). In this way, the grammar
provides a catalog of possible rights that can be associated with
parts of digital works. In the following, rights are divided into
categories for convenience in describing them.
[0112] Grammar element 1504 "Render-Code:=[Play: {Player:
Player-ID}|Print: {Printer: Printer-ID}]" lists a category of
rights all involving the making of ephemeral, transitory, or
non-digital copies of the digital work. After use the copies are
erased.
[0113] Play: A process of rendering or performing a digital work on
some processor. This includes such things as playing digital
movies, playing digital music, playing a video game, running a
computer program, or displaying a document on a display.
[0114] Print: To render the work in a medium that is not further
protected by usage rights, such as printing on paper.
[0115] Grammar element 1505
"Transport-Code:=[Copy|Transfer|Loan{Remaining-Rights:
Next-Set-of-Rights}]{(Next-Copy-Rights: Next-Set of Rights)}" lists
a category of rights involving the making of persistent, usable
copies of the digital work on other repositories. The optional
Next-Copy-Rights determine the rights on the work after it is
transported. If this is not specified, then the rights on the
transported copy are the same as on the original. The optional
Remaining-Rights specify the rights that remain with a digital work
when it is loaned out. If this is not specified, then the default
is that no rights can be exercised when it is loaned out.
[0116] Copy: Make a new copy of a work
[0117] Transfer: Moving a work from one repository to another.
[0118] Loan: Temporarily loaning a copy to another repository for a
specified period of time.
[0119] Grammar element 1506 "File-Management-Code:=Backup
{Back-Up-Copy-Rights: Next-Set-of Rights}
|Restore|Delete|Folder|Directory {Name:Hide-Local|Hide-Remote}
{Parts:Hide-Local|Hide-Remote}" lists a category of rights
involving operations for file management, such as the making of
backup copies to protect the copy owner against catastrophic
equipment failure.
[0120] Many software licenses and also copyright law give a copy
owner the right to make backup copies to protect against
catastrophic failure of equipment. However, the making of
uncontrolled backup copies is inherently at odds with the ability
to control usage, since an uncontrolled backup copy can be kept and
then restored even after the authorized copy was sold.
[0121] The File management rights enable the making and restoring
of backup copies in a way that respects usage rights, honoring the
requirements of both the copy owner and the rights grantor and
revenue owner. Backup copies of work descriptions (including usage
rights and fee data) can be sent under appropriate protocol and
usage rights control to other document repositories of sufficiently
high security. Further rights permit organization of digital works
into folders which themselves are treated as digital works and
whose contents may be "hidden" from a party seeking to determine
the contents of a repository.
[0122] Backup: To make a backup copy of a digital work as
protection against media failure.
[0123] Restore: To restore a backup copy of a digital work.
[0124] Delete: To delete or erase a copy of a digital work.
[0125] Folder: To create and name folders, and to move files and
folders between folders.
[0126] Directory: To hide a folder or it's contents.
[0127] Grammar element 1507 "Derivative-Works-Code:
[Extract|Embed|Edit {Process: Process-ID}] {Next-Copy-Rights:
Next-Set-of Rights}" lists a category of rights involving the use
of a digital work to create new works.
[0128] Extract: To remove a portion of a work, for the purposes of
creating a new work.
[0129] Embed: To include a work in an existing work.
[0130] Edit: To alter a digital work by copying, selecting and
modifying portions of an existing digital work.
[0131] Grammar element 1508 "Configuration-Code:=Install|Uninstall"
lists a category of rights for installing and uninstalling software
on a repository (typically a rendering repository.) This would
typically occur for the installation of a new type of player within
the rendering repository.
[0132] Install: To install new software on a repository.
[0133] Uninstall: To remove existing software from a
repository.
[0134] Grammar element 1509 "Next-Set-of-Rights:={(Add:
Set-Of-Rights)} {(Delete: Set-Of-Rights)} {(Replace:
Set-Of-Rights)} {(Keep: Set-Of-Rights)}" defines how rights are
carried forward for a copy of a digital work. If the
Next-Copy-Rights is not specified, the rights for the next copy are
the same as those of the current copy. Otherwise, the set of rights
for the next copy can be specified. Versions of rights after Add:
are added to the current set of rights. Rights after Delete: are
deleted from the current set of rights. If only right codes are
listed after Delete:, then all versions of rights with those codes
are deleted. Versions of rights after Replace: subsume all versions
of rights of the same type in the current set of rights.
[0135] If Remaining-Rights is not specified, then there are no
rights for the original after all Loan copies are loaned out. If
Remaining-Rights is specified, then the Keep: token can be used to
simplify the expression of what rights to keep behind. A list of
right codes following keep means that all of the versions of those
listed rights are kept in the remaining copy. This specification
can be overridden by subsequent Delete: or Replace:
specifications.
Copy Count Specification
[0136] For various transactions, it may be desirable to provide
some limit as to the number of "copies" of the work which may be
exercised simultaneously for the right. For example, it may be
desirable to limit the number of copies of a digital work that may
be loaned out at a time or viewed at a time.
[0137] Grammar element 1510 "Copy-Count:=(Copies:
positive-integer|0|unlimited)" provides a condition which defines
the number of "copies" of a work subject to the right. A copy count
can be 0, a fixed number, or unlimited. The copy-count is
associated with each right, as opposed to there being just a single
copy-count for the digital work. The Copy-Count for a right is
decremented each time that a right is exercised. When the
Copy-Count equals zero, the right can no longer be exercised. If
the Copy-Count is not specified, the default is one.
Control Specification
[0138] Rights and fees depend in general on rights granted by the
creator as well as further restrictions imposed by later
distributors. Control specifications deal with interactions between
the creators and their distributors governing the imposition of
further restrictions and fees. For example, a distributor of a
digital work may not want an end consumer of a digital work to add
fees or otherwise profit by commercially exploiting the purchased
digital work.
[0139] Grammar element 1511 "Control-Spec:=(Control:
{Restrictable|Unrestrictable} {Unchargeable|Chargeable}-)" provides
a condition to specify the effect of usage rights and fees of
parents on the exercise of the right. A digital work is
restrictable if higher level d-blocks can impose further
restrictions (time specifications and access specifications) on the
right. It is unrestrictable if no further restrictions can be
imposed. The default setting is restrictable. A right is
unchargeable if no more fees can be imposed on the use of the
right. It is chargeable if more fees can be imposed. The default is
chargeable.
Time Specification
[0140] It is often desirable to assign a start date or specify some
duration as to when a right may be exercised. Grammar element 1512
"Time-Spec:=({Fixed-Interval|Sliding-Interval|Meter-Tim-e} Until:
Expiration-Date)" provides for specification of time conditions on
the exercise of a right. Rights may be granted for a specified
time. Different kinds of time specifications are appropriate for
different kinds of rights. Some rights may be exercised during a
fixed and predetermined duration. Some rights may be exercised for
an interval that starts the first time that the right is invoked by
some transaction. Some rights may be exercised or are charged
according to some kind of metered time, which may be split into
separate intervals. For example, a right to view a picture for an
hour might be split into six ten minute viewings or four fifteen
minute viewings or twenty three minute viewings.
[0141] The terms "time" and "date" are used synonymously to refer
to a moment in time. There are several kinds of time
specifications. Each specification represents some limitation on
the times over which the usage right applies. The Expiration-Date
specifies the moment at which the usage right ends. For example, if
the Expiration-Date is "Jan. 1, 1995," then the right ends at the
first moment of 1995. If the Expiration-Date is specified as
*forever*, then the rights are interpreted as continuing without
end. If only an expiration date is given, then the right can be
exercised as often as desired until the expiration date.
[0142] Grammar element 1513 "Fixed-Interval:=From: Start-Time" is
used to define a predetermined interval that runs from the start
time to the expiration date.
[0143] Grammar element 1514 "Sliding-Interval:=Interval:
Use-Duration" is used to define an indeterminate (or "open") start
time. It sets limits on a continuous period of time over which the
contents are accessible. The period starts on the first access and
ends after the duration has passed or the expiration date is
reached, whichever comes first. For example, if the right gives 10
hours of continuous access, the use-duration would begin when the
first access was made and end 10 hours later.
[0144] Grammar element 1515 "Meter-Time:=Time-Remaining:
Remaining-Use" is used to define a "meter time," that is, a measure
of the time that the right is actually exercised. It differs from
the Sliding-Interval specification in that the time that the
digital work is in use need not be continuous. For example, if the
rights guarantee three days of access, those days could be spread
out over a month. With this specification, the rights can be
exercised until the meter time is exhausted or the expiration date
is reached, whichever comes first.
[0145] Remaining-Use:=Time-Unit
[0146] Start-Time:=Time-Unit
[0147] Use-Duration:=Time-Unit
[0148] All of the time specifications include time-unit
specifications in their ultimate instantiation.
Security Class and Authorization Specification
[0149] The present invention provides for various security
mechanisms to be introduced into a distribution or use scheme.
Grammar element 1516 "Access-Spec:=({SC: Security-Class}
{Authorization: Authorization-ID*} {Other-Authorization:
Authorization-ID*} {Ticket: Ticket-ID})" provides a means for
restricting access and transmission. Access specifications can
specify a required security class for a repository to exercise a
right or a required authorization test that must be satisfied.
[0150] The keyword "SC:" is used to specify a minimum security
level for the repositories involved in the access. If "SC:" is not
specified, the lowest security level is acceptable.
[0151] The optional "Authorization:" keyword is used to specify
required authorizations on the same repository as the work. The
optional "Other-Authorization:" keyword is used to specify required
authorizations on the other repository in the transaction.
[0152] The optional "Ticket:" keyword specifies the identity of a
ticket required for the transaction. A transaction involving
digital tickets must locate an appropriate digital ticket agent who
can "punch" or otherwise validate the ticket before the transaction
can proceed. Tickets are described in greater detail below.
[0153] In a transaction involving a repository and a document
server, some usage rights may require that the repository have a
particular authorization, that the server have some authorization,
or that both repositories have (possibly different) authorizations.
Authorizations themselves are digital works (hereinafter referred
to as an authorization object) that can be moved between
repositories in the same manner as other digital works. Their
copying and transferring is subject to the same rights and fees as
other digital works. A repository is said to have an authorization
if that authorization object is contained within the
repository.
[0154] In some cases, an authorization may be required from a
source other than the document server and repository. An
authorization object referenced by an Authorization-ID can contain
digital address information to be used to set up a communications
link between a repository and the authorization source. These are
analogous to phone numbers. For such access tests, the
communication would need to be established and authorization
obtained before the right could be exercised.
[0155] For one-time usage rights, a variant on this scheme is to
have a digital ticket. A ticket is presented to a digital ticket
agent, whose type is specified on the ticket. In the simplest case,
a certified generic ticket agent, available on all repositories, is
available to "punch" the ticket. In other cases, the ticket may
contain addressing information for locating a "special" ticket
agent. Once a ticket has been punched, it cannot be used again for
the same kind of transaction (unless it is unpunched or refreshed
in the manner described below.) Punching includes marking the
ticket with a timestamp of the date and time it was used. Tickets
are digital works and can be copied or transferred between
repositories according to their usage rights.
[0156] In the currently preferred embodiment, a "punched" ticket
becomes "unpunched" or "refreshed" when it is copied or extracted.
The Copy and Extract operations save the date and time as a
property of the digital ticket. When a ticket agent is given a
ticket, it can simply check whether the digital copy was made after
the last time that it was punched. Of course, the digital ticket
must have the copy or extract usage rights attached thereto.
[0157] The capability to unpunch a ticket is important in the
following cases:
[0158] A digital work is circulated at low cost with a limitation
that it can be used only once.
[0159] A digital work is circulated with a ticket that can be used
once to give discounts on purchases of other works.
[0160] A digital work is circulated with a ticket (included in the
purchase price and possibly embedded in the work) that can be used
for a future upgrade.
[0161] In each of these cases, if a paid copy is made of the
digital work (including the ticket) the new owner would expect to
get a fresh (unpunched) ticket, whether the copy seller has used
the work or not. In contrast, loaning a work or simply transferring
it to another repository should not revitalize the ticket.
Usage Fees and Incentives Specification
[0162] The billing for use of a digital work is fundamental to a
commercial distribution system. Grammar Element 1517
"Fee-Spec:={Scheduled-Discount}
Regular-Fee-Spec|Scheduled-Fee-Spec|Markup-Spec" provides a range
of options for billing for the use of digital works.
[0163] A key feature of this approach is the development of
low-overhead billing for transactions in potentially small amounts.
Thus, it becomes feasible to collect fees of only a few cents each
for thousands of transactions.
[0164] The grammar differentiates between uses where the charge is
per use from those where it is metered by the time unit.
Transactions can support fees that the user pays for using a
digital work as well as incentives paid by the right grantor to
users to induce them to use or distribute the digital work.
[0165] The optional scheduled discount refers to the rest of the
fee specification--discounting it by a percentage over time. If it
is not specified, then there is no scheduled discount. Regular fee
specifications are constant over time. Scheduled fee specifications
give a schedule of dates over which the fee specifications change.
Markup specifications are used in d-blocks for adding a percentage
to the fees already being charged.
[0166] Grammar Element 1518
"Scheduled-Discount:=(Scheduled-Discount: (Time-Spec Percentage)*)"
A Scheduled-Discount is essentially a scheduled modifier of any
other fee specification for this version of the right of the
digital work. (It does not refer to children or parent digital
works or to other versions of rights.). It is a list of pairs of
times and percentages. The most recent time in the list that has
not yet passed at the time of the transaction is the one in effect.
The percentage gives the discount percentage. For example, the
number 10 refers to a 10% discount.
[0167] Grammar Element 1519 "Regular-Fee-Spec:=({Fee:|Incentive:}
[Per-Use-Spec|Metered-Rate-Spec|Best-Price-Spec|Call-For-Price-Spec]
{Min: Money-Unit Per: Time-Spec} {Max: Money-Unit Per: Time-Spec}
To: Account-ID)" provides for several kinds of fee
specifications.
[0168] Fees are paid by the copy-owner/user to the revenue-owner if
Fee: is specified. Incentives are paid by the revenue-owner to the
user if Incentive: is specified. If the Min: specification is
given, then there is a minimum fee to be charged per time-spec unit
for its use. If the Max: specification is given, then there is a
maximum fee to be charged per time-spec for its use. When Fee: is
specified, Account-ID identifies the account to which the fee is to
be paid. When Incentive: is specified, Account-ID identifies the
account from which the fee is to be paid.
[0169] Grammar element 1520 "Per-Use-Spec:=Per-Use: Money-unit"
defines a simple fee to be paid every time the right is exercised,
regardless of how much time the transaction takes.
[0170] Grammar element 1521 "Metered-Rate-Spec:=Metered: Money-Unit
Per: Time-Spec" defines a metered-rate fee paid according to how
long the right is exercised. Thus, the time it takes to complete
the transaction determines the fee.
[0171] Grammar, element 1522 "Best-Price-Spec:=Best-Price:
Money-unit Max: Money-unit" is used to specify a best-price that is
determined when the account is settled. This specification is to
accommodate special deals, rebates, and pricing that depends on
information that is not available to the repository. All fee
specifications can be combined with tickets or authorizations that
could indicate that the consumer is a wholesaler or that he is a
preferred customer, or that the seller be authorized in some way.
The amount of money in the Max: field is the maximum amount that
the use will cost. This is the amount that is tentatively debited
from the credit server. However, when the transaction is ultimately
reconciled, any excess amount will be returned to the consumer in a
separate transaction.
[0172] Grammar element 1523 "Call-For-Price-Spec:=Call-For-Price"
is similar to a "Best-Price-Spec" in that it is intended to
accommodate cases where prices are dynamic. A Call-For-Price Spec
requires a communication with a dealer to determine the price. This
option cannot be exercised if the repository cannot communicate
with a dealer at the time that the right is exercised. It is based
on a secure transaction whereby the dealer names a price to
exercise the right and passes along a deal certificate which is
referenced or included in the billing process.
[0173] Grammar element 1524 "Scheduled-Fee-Spec:=(Schedule:
(Time-Spec Regular-Fee-Spec)*)" is used to provide a schedule of
dates over which the fee specifications change. The fee
specification with the most recent date not in the future is the
one that is in effect. This is similar to but more general than the
scheduled discount. It is more general, because it provides a means
to vary the fee agreement for each time period.
[0174] Grammar element 1525 "Markup-Spec:=Markup: percentage To:
Account-ID" is provided for adding a percentage to the fees already
being charged. For example, a 5% markup means that a fee of 5% of
cumulative fee so far will be allocated to the distributor. A
markup specification can be applied to all of the other kinds of
fee specifications. It is typically used in a shell provided by a
distributor. It refers to fees associated with d-blocks that are
parts of the current d-block. This might be a convenient
specification for use in taxes, or in distributor overhead.
Examples of Sets of Usage Rights
[0175] ((Play) (Transfer (SC: 3)) (Delete)
[0176] This work can be played without requirements for fee or
authorization on any rendering system. It can be transferred to any
other repository of security level 3 or greater. It can be
deleted.
[0177] ((Play) (Transfer (SC: 3)) (Delete) (Backup) (Restore
(Fee:Per-Use: $5 To: Account-ID-678)))
[0178] Same as the previous example plus rights for backup and
restore. The work can be backed up without fee. It can be restored
for a $5 fee payable to the account described by
Account-ID-678.
[0179] ((Play) (Transfer (SC: 3))
[0180] (Copy (SC:3)(Fee: Per-Use: $5 To: Account-ID-678))
[0181] (Delete (Incentive: Per-Use: $2.50 To: Account-ID-678)))
[0182] This work can be played, transferred, copied, or deleted.
Copy or transfer operations can take place only with repositories
of security level three or greater. The fee to make a copy is $5
payable to Account-ID-678. If a copy is deleted, then an incentive
of $2.50 is paid to the former copy owner.
[0183] ((Play) (Transfer (SC: 3))
[0184] Copy (SC: 3) (Fee: Per-Use: $10 To: Account-ID-678))
[0185] Delete) (Backup) (Restore (SC: 3) (Fee: Per-Use: $5 To:
Account-ID-678)))
[0186] Same as the previous example plus fees for copying. The work
can be copied digitally for a fee of $10 payable to Account-ID-678.
The repository on which the work is copied or restored must be at
security level 3 or greater.
[0187] ((Play) (Transfer (SC: 3))
[0188] (Copy Authorization: License-123-ID (SC: 3)))
[0189] The digital work can be played, transferred, or copied.
Copies or transfers must be on repositories of security level 3 or
greater. Copying requires the license License-123-ID issued to the
copying repository. None of the rights require fees.
[0190] ((Play) (Print Printer: Printer-567-ID (Fee: Per-Use: $1 To:
Account-ID-678)))
[0191] This work can be played for free. It can be printed on any
printer with the identifier Printer-567-ID for a fee of $1 payable
to the account described by Account-ID-678.
[0192] ((Play Player: Player-876-ID) (From: Feb. 2, 1994 Until:
Feb. 15, 1995) (Fee: Metered: $0.01 Per: 0:1:0 Min: $0.25 Per:
0/1/0 To: Account-ID-567))
[0193] This work can be played on any player holding the ID
Player-876-ID. The time of this right is from Feb. 14, 1994 until
Feb. 15, 1995. The fee for use is one cent per minute with a
minimum of 25 cents in any day that it is used, payable to the
account described by Account-ID-567.
[0194] ((Play) (Transfer) (Delete)(Loan 2 (Delete: Transfer
Loan)))
[0195] This work can be played, transferred, deleted, or loaned. Up
to two copies can be loaned out at a time. The loaned copy has the
same rights except that it cannot be transferred. When both copies
are loaned out, no rights can be exercised on the original on the
repository.
[0196] ((Play) (Transfer) (Delete) (Backup) (Restore (SC:3))
[0197] (Loan 2 Remaining-Copy-Rights: (Delete: Play Transfer)
[0198] Next-Set-of-Rights: (Delete: Transfer Loan)))
[0199] Similar to previous example. Rights to Backup and Restore
the work are added, where restoration requires a repository of at
least security level three. When all copies of the work are loaned
out, the remaining copy cannot be played or transferred.
[0200] ((Play) (Transfer) (Copy) (Print) (Backup) (Restore
(SC:3))
[0201] (Loan 1 Remaining-Copy-Rights: (Add: Play Print Backup)
[0202] Next-Set-of-Rights: (Delete: Transfer Loan)
[0203] (Fee: Metered: $10 Per: 1:0:0 To: Account-ID-567))
[0204] (Loan 1 Remaining-Copy-Rights:
[0205] Add: ((Play Player: Player-876-ID) 2 (From: Feb. 14, 1994
Until: Feb. 15, 1995)
[0206] (Fee: Metered: $0.01 Per: 0:1:0 Min: $0.25 Per: 0/1/0
[0207] To: Account-ID-567))))
[0208] The original work has rights to Play, Transfer, Copy, Print,
Backup, Restore, and Loan. There are two versions of the Loan
right. The first version of the loan right costs $10 per day but
allows the original copy owner to exercise free use of the Play,
Print and Backup rights. The second version of the Loan right is
free. None of the original rights are applicable. However a right
to Play the work at the specified metered rate is added.
[0209] ((Play Player: Player-Small-Screen-123-ID)
[0210] (Embed (Fee: Per-Use $0.01 To: Account-678-ID))
[0211] (Copy (Fee: Per-Use $1.00 To: Account-678-ID)))
[0212] The digital work can be played on any player with the
identifier Player-Small-Screen-123-ID. It can be embedded in a
larger work. The embedding requires a modest one cent registration
fee to Account-678-ID. Digital copies can be made for $1.00.
Repository Transactions
[0213] When a user requests access to a digital work, the
repository will initiate various transactions. The combination of
transactions invoked will depend on the specifications assigned for
a usage right. There are three basic types of transactions, Session
Initiation Transactions, Financial Transactions and Usage
Transactions. Generally, session initiation transactions are
initiated first to establish a valid session. When a valid session
is established, transactions corresponding to the various usage
rights are invoked. Finally, request specific transactions are
performed.
[0214] Transactions occur between two repositories (one acting as a
server), between a repository and a document playback platform
(e.g. for executing or viewing), between a repository and a credit
server or between a repository and an authorization server. When
transactions occur between more than one repository, it is assumed
that there is a reliable communication channel between the
repositories. For example, this could be a TCP/IP channel or any
other commercially available channel that has built-in capabilities
for detecting and correcting transmission errors. However, it is
not assumed that the communication channel is secure. Provisions
for security and privacy are part of the requirements for
specifying and implementing repositories and thus form the need for
various transactions.
Message Transmission
[0215] Transactions require that there be some communication
between repositories. Communication between repositories occurs in
units termed as messages. Because the communication line is assumed
to be unsecure, all communications with repositories that are above
the lowest security class are encrypted utilizing a public key
encryption technique. Public key encryption is a well known
technique in the encryption arts. The term key refers to a numeric
code that is used with encryption and decryption algorithms. Keys
come in pairs, where "writing keys" are used to encrypt data and
"checking keys" are used to decrypt data. Both writing and checking
keys may be public or private. Public keys are those that are
distributed to others. Private keys are maintained in
confidence.
[0216] Key management and security is instrumental in the success
of a public key encryption system. In the currently preferred
embodiment, one or more master repositories maintain the keys and
create the identification certificates used by the
repositories.
[0217] When a sending repository transmits a message to a receiving
repository, the sending repository encrypts all of its data using
the public writing key of the receiving repository. The sending
repository includes its name, the name of the receiving repository,
a session identifier such as a nonce (described below), and a
message counter in each message.
[0218] In this way, the communication can only be read (to a high
probability) by the receiving repository, which holds the private
checking key for decryption. The auxiliary data is used to guard
against various replay attacks to security. If messages ever arrive
with the wrong counter or an old nonce, the repositories can assume
that someone is interfering with communication and the transaction
terminated.
[0219] The respective public keys for the repositories to be used
for encryption are obtained in the registration transaction
described below.
Session Initiation Transactions
[0220] A usage transaction is carried out in a session between
repositories. For usage transactions involving more than one
repository, or for financial transactions between a repository and
a credit server, a registration transaction is performed. A second
transaction termed a login transaction, may also be needed to
initiate the session. The goal of the registration transaction is
to establish a secure channel between two repositories who know
each others identities. As it is assumed that the communication
channel between the repositories is reliable but not secure, there
is a risk that a non-repository may mimic the protocol in order to
gain illegitimate access to a repository.
[0221] The registration transaction between two repositories is
described with respect to FIGS. 16 and 17. The steps described are
from the perspective of a "repository-1" registering its identity
with a "repository-2". The registration must be symmetrical so the
same set of steps will be repeated for repository-2 registering its
identity with repository-1. Referring to FIG. 16, repository-1
first generates an encrypted registration identifier, step 1601 and
then generates a registration message, step 1602. A registration
message is comprised of an identifier of a master repository, the
identification certificate for the repository-1 and an encrypted
random registration identifier. The identification certificate is
encrypted by the master repository in its private key and attests
to the fact that the repository (here repository-1) is a bona fide
repository. The identification certificate also contains a public
key for the repository, the repository security level and a
timestamp (indicating a time after which the certificate is no
longer valid.) The registration identifier is a number generated by
the repository for this registration. The registration identifier
is unique to the session and is encrypted in repository-1's private
key. The registration identifier is used to improve security of
authentication by detecting certain kinds of communications based
attacks. Repository-1 then transmits the registration message to
repository-2, step 1603.
[0222] Upon receiving the registration message, repository-2
determines if it has the needed public key for the master
repository, step 1604. If repository-2 does not have the needed
public key to decrypt the identification certificate, the
registration transaction terminates in an error, step 1618.
[0223] Assuming that repository-2 has the proper public key the
identification certificate is decrypted, step 1605. Repository-2
saves the encrypted registration identifier, step 1606, and
extracts the repository identifier, step 1607. The extracted
repository identifier is checked against a "hotlist" of compromised
document repositories, step 1608. In the currently preferred
embodiment, each repository will contain "hotlists" of compromised
repositories. If the repository is on the "hotlist", the
registration transaction terminates in an error per step 1618.
Repositories can be removed from the hotlist when their
certificates expire, so that the list does not need to grow without
bound. Also, by keeping a short list of hotlist certificates that
it has previously received, a repository can avoid the work of
actually going through the list. These lists would be encrypted by
a master repository. A minor variation on the approach to improve
efficiency would have the repositories first exchange lists of
names of hotlist certificates, ultimately exchanging only those
lists that they had not previously received. The "hotlists" are
maintained and distributed by Master repositories.
[0224] Note that rather than terminating in error, the transaction
could request that another registration message be sent based on an
identification certificate created by another master repository.
This may be repeated until a satisfactory identification
certificate is found, or it is determined that trust cannot be
established.
[0225] Assuming that the repository is not on the hotlist, the
repository identification needs to be verified. In other words,
repository-2 needs to validate that the repository on the other end
is really repository-1. This is termed performance testing and is
performed in order to avoid invalid access to the repository via a
counterfeit repository replaying a recording of a prior session
initiation between repository-1 and repository-2. Performance
testing is initiated by repository-2 generating a performance
message, step 1609. The performance message consists of a nonce,
the names of the respective repositories, the time and the
registration identifier received from repository-1. A nonce is a
generated message based on some random and variable information
(e.g. the time or the temperature.) The nonce is used to check
whether repository-I can actually exhibit correct encrypting of a
message using the private keys it claims to have, on a message that
it has never seen before. The performance message is encrypted
using the public key specified in the registration message of
repository-1. The performance message is transmitted to
repository-1, step 1610, where it is decrypted by repository-1
using its private key, step 1611. Repository-1 then checks to make
sure that the names of the two repositories are correct, step 1612,
that the time is accurate, step 1613 and that the registration
identifier corresponds to the one it sent, step 1614. If any of
these tests fails, the transaction is terminated per step 1616.
Assuming that the tests are passed, repository-1 transmits the
nonce to repository-2 in the clear, step 1615. Repository-2 then
compares the received nonce to the original nonce, step 1617. If
they are not identical, the registration transaction terminates in
an error per step 1618. If they are the same, the registration
transaction has successfully completed.
[0226] At this point, assuming that the transaction has not
terminated, the repositories exchange messages containing session
keys to be used in all communications during the session and
synchronize their clocks. FIG. 17 illustrates the session
information exchange and clock synchronization steps (again from
the perspective of repository-1.) Referring to FIG. 17,
repository-1 creates a session key pair, step 1701. A first key is
kept private and is used by repository-1 to encrypt messages. The
second key is a public key used by repository-2 to decrypt
messages. The second key is encrypted using the public key of
repository-2, step 1702 and is sent to repository-2, step 1703.
Upon receipt, repository-2 decrypts the second key, step 1704. The
second key is used to decrypt messages in subsequent
communications. When each repository has completed this step, they
are both convinced that the other repository is bona fide and that
they are communicating with the original. Each repository has given
the other a key to be used in decrypting further communications
during the session. Since that key is itself transmitted in the
public key of the receiving repository only it will be able to
decrypt the key which is used to decrypt subsequent messages.
[0227] After the session information is exchanged, the repositories
must synchronize their clocks. Clock synchronization is used by the
repositories to establish an agreed upon time base for the
financial records of their mutual transactions. Referring back to
FIG. 17, repository-2 initiates clock synchronization by generating
a time stamp exchange message, step 1705, and transmits it to
repository-1, step 1706. Upon receipt, repository-1 generates its
own time stamp message, step 1707 and transmits it back to
repository-2, step 1708. Repository-2 notes the current time, step
1709 and stores the time received from repository-1, step 1710. The
current time is compared to the time received from repository-1,
step 1711. The difference is then checked to see if it exceeds a
predetermined tolerance (e.g. one minute), step 1712. If it does,
repository-2 terminates the transaction as this may indicate
tampering with the repository, step 1713. If not repository-2
computes an adjusted time delta, step 1714. The adjusted time delta
is the difference between the clock time of repository-2 and the
average of the times from repository-1 and repository-2.
[0228] To achieve greater accuracy, repository-2 can request the
time again up to a fixed number of times (e.g. five times), repeat
the clock synchronization steps, and average the results.
[0229] A second session initiation transaction is a Login
transaction. The Login transaction is used to check the
authenticity of a user requesting a transaction. A Login
transaction is particularly prudent for the authorization of
financial transactions that will be charged to a credit server. The
Login transaction involves an interaction between the user at a
user interface and the credit server associated with a repository.
The information exchanged here is a login string supplied by the
repository/credit server to identify itself to the user, and a
Personal Identification Number (PIN) provided by the user to
identify himself to the credit server. In the event that the user
is accessing a credit server on a repository different from the one
on which the user interface resides, exchange of the information
would be encrypted using the public and private keys of the
respective repositories.
Billing Transactions
[0230] Billing Transactions are concerned with monetary transaction
with a credit server. Billing Transactions are carried out when all
other conditions are satisfied and a usage fee is required for
granting the request. For the most part, billing transactions are
well understood in the state of the art. These transactions are
between a repository and a credit server, or between a credit
server and a billing clearinghouse. Briefly, the required
transactions include the following:
[0231] Registration and LOGIN transactions, by which the repository
and user establish their bona fides to a credit server. These
transactions would be entirely internal in cases where the
repository and credit server are implemented as a single
system.
[0232] Registration and LOGIN transactions, by which a credit
server establishes its bona fides to a billing clearinghouse.
[0233] An Assign-fee transaction to assign a charge. The
information in this transaction would include a transaction
identifier, the identities of the repositories in the transaction,
and a list of charges from the parts of the digital work. If there
has been any unusual event in the transaction such as an
interruption of communications, that information is included as
well.
[0234] A Begin-charges transaction to assign a charge. This
transaction is much the same as an assign-fee transaction except
that it is used for metered use. It includes the same information
as the assign-fee 4, ii transaction as well as the usage fee
information. The credit-server is then responsible for running a
clock.
[0235] An End-charges transaction to end a charge for metered use.
(In a variation on this approach, the repositories would exchange
periodic charge information for each block of time.)
[0236] A report-charges transaction between a personal credit
server and a billing clearinghouse. This transaction is invoked at
least once per billing period. It is used to pass along information
about charges. On debit and credit cards, this transaction would
also be used to update balance information and credit limits as
needed.
[0237] All billing transactions are given a transaction ID and are
reported to the credit severs by both the server and the client.
This reduces possible loss of billing information if one of the
parties to a transaction loses a banking card and provides a check
against tampering with the system.
Usage Transactions
[0238] After the session initiation transactions have been
completed, the usage request may then be processed. To simplify the
description of the steps carried out in processing a usage request,
the term requester is used to refer to a repository in the
requester mode which is initiating a request, and the term server
is used to refer to a repository in the server mode and which
contains the desired digital work. In many cases such as requests
to print or view a work, the requester and server may be the same
device and the transactions described in the following would be
entirely internal. In such instances, certain transaction steps,
such as the registration transaction, need not be performed.
[0239] There are some common steps that are part of the semantics
of all of the usage rights transactions. These steps are referred
to as the common transaction steps. There are two sets--the
"opening" steps and the "closing" steps. For simplicity, these are
listed here rather than repeating them in the descriptions of all
of the usage rights transactions.
[0240] Transactions can refer to a part of a digital work, a
complete digital work, or a Digital work containing other digital
works. Although not described in detail herein, a transaction may
even refer to a folder comprised of a plurality of digital works.
The term "work" is used to refer to what ever portion or set of
digital works is being accessed.
[0241] Many of the steps here involve determining if certain
conditions are satisfied. Recall that each usage right may have one
or more conditions which must be satisfied before the right can be
exercised. Digital works have parts and parts have parts. Different
parts can have different rights and fees. Thus, it is necessary to
verify that the requirements are met for ALL of the parts that are
involved in a transaction For brevity, when reference is made to
checking whether the rights exist and conditions for exercising are
satisfied, it is meant that all such checking takes place for each
of the relevant parts of the work.
[0242] FIG. 18 illustrates the initial common opening and closing
steps for a transaction. At this point it is assumed that
registration has occurred and that a "trusted" session is in place.
General tests are tests on usage rights associated with the folder
containing the work or some containing folder higher in the file
system hierarchy. These tests correspond to requirements imposed on
the work as a consequence of its being on the particular
repository, as opposed to being attached to the work itself.
Referring to FIG. 18, prior to initiating a usage transaction, the
requester performs any general tests that are required before the
right associated with the transaction can be exercised, step, 1801.
For example, install, uninstall and delete rights may be
implemented to require that a requester have an authorization
certificate before the right can be exercised. Another example is
the requirement that a digital ticket be present and punched before
a digital work may be copied to a requester. If any of the general
tests fail, the transaction is not initiated, step, 1802. Assuming
that such required tests are passed, upon receiving the usage
request, the server generates a transaction identifier that is used
in records or reports of the transaction, step 1803. The server
then checks whether the digital work has been granted the right
corresponding to the requested transaction, step 1804. If the
digital work has not been granted the right corresponding to the
request, the transaction terminates, step 1805. If the digital work
has been granted the requested right, the server then determines if
the various conditions for exercising the right are satisfied. Time
based conditions are examined, step 1806. These conditions are
checked by examining the time specification for the version of the
right. If any of the conditions are not satisfied, the transaction
terminates per step 1805.
[0243] Assuming that the time based conditions are satisfied, the
server checks security and access conditions, step 1807. Such
security and access conditions are satisfied if: 1) the requester
is at the specified security class, or a higher security class, 2)
the server satisfies any specified authorization test and 3) the
requester satisfies any specified authorization tests and has any
required digital tickets. If any of the conditions are not
satisfied, the transaction terminates per step 1805.
[0244] Assuming that the security and access conditions are all
satisfied, the server checks the copy count condition, step 1808.
If the copy count equals zero, then the transaction cannot be
completed and the transaction terminates per step 1805.
[0245] Assuming that the copy count does not equal zero, the server
checks if the copies in use for the requested right is greater than
or equal to any copy count for the requested right (or relevant
parts), step 1809. If the copies in use are greater than or equal
to the copy count, this indicates that usage rights for the version
of the transaction have been exhausted. Accordingly, the server
terminates the transaction, step 1805. If the copy count is less
than the copies in use for the transaction the transaction can
continue, and the copies in use would be incremented by the number
of digital works requested in the transaction, step 1810.
[0246] The server then checks if the digital work has a "Loan"
access right, step 1811. The "Loan" access right is a special case
since remaining rights may be present even though all copies are
loaned out. If the digital work has the "Loan" access right, a
check is made to see if all copies have been loaned out, step 1812.
The number of copies that could be loaned is the sum of the
Copy-Counts for all of the versions of the loan right of the
digital work. For a composite work, the relevant figure is the
minimal such sum of each of the components of the composite work.
If all copies have been loaned out, the remaining rights are
determined, step 1813. The remaining-rights are determined from the
remaining rights specifications from the versions of the Loan
right. If there is only one version of the Loan right, then the
determination is simple. The remaining rights are the ones
specified in that version of the Loan right, or none if
Remaining-Rights: is not specified. If there are multiple versions
of the Loan right and all copies of all of the versions are loaned
out, then the remaining rights is taken as the minimum set
(intersection) of remaining rights across all of the versions of
the loan right. The server then determines if the requested right
is in the set of remaining rights, step 1814. If the requested
right is not in the set of remaining rights, the server terminates
the transaction, step 1805.
[0247] If Loan is not a usage right for the digital work or if all
copies have not been loaned out or the requested right is in the
set of remaining rights, fee conditions for the right are then
checked, step 1815. This will initiate various financial
transactions between the repository and associated credit server.
Further, any metering of usage of a digital work will commence. If
any financial transaction fails, the transaction terminates per
step 1805.
[0248] It should be noted that the order in which the conditions
are checked need not follow the order of steps 1806-1815.
[0249] At this point, right specific steps are now performed and
are represented here as step 1816. The right specific steps are
described in greater detail below.
[0250] The common closing transaction steps are now performed. Each
of the closing transaction steps are performed by the server after
a successful completion of a transaction. Referring back to FIG.
18, the copies in use value for the requested right is decremented
by the number of copies involved in the transaction, step 1817.
Next, if the right had a metered usage fee specification, the
server subtracts the elapsed time from the Remaining-Use-Time
associated with the right for every part involved in the
transaction, step 1818. Finally, if there are fee specifications
associated with the right, the server initiates End-Charge
financial transaction to confirm billing, step 1819.
Transmission Protocol
[0251] An important area to consider is the transmission of the
digital work from the server to the requester. The transmission
protocol described herein refers to events occurring after a valid
session has been created. The transmission protocol must handle the
case of disruption in the communications between the repositories.
It is assumed that interference such as injecting noise on the
communication channel can be detected by the integrity checks
(e.g., parity, checksum, etc.) that are built into the transport
protocol and are not discussed in detail herein.
[0252] The underlying goal in the transmission protocol is to
preclude certain failure modes, such as malicious or accidental
interference on the communications channel. Suppose, for example,
that a user pulls a card with the credit server at a specific time
near the end of a transaction. There should not be a vulnerable
time at which "pulling the card" causes the repositories to fail to
correctly account for the number of copies of the work that have
been created. Restated, there should be no time at which a party
can break a connection as a means to avoid payment after using a
digital work.
[0253] If a transaction is interrupted (and fails), both
repositories restore the digital works and accounts to their state
prior to the failure, modulo records of the failure itself.
[0254] FIG. 19 is a state diagram showing steps in the process of
transmitting information during a transaction. Each box represents
a state of a repository in either the server mode (above the
central dotted line 1901) or in the requester mode (below the
dotted line 1901). Solid arrows stand for transitions between
states. Dashed arrows stand for message communications between the
repositories. A dashed message arrow pointing to a solid transition
arrow is interpreted as meaning that the transition takes place
when the message is received. Unlabeled transition arrows take
place unconditionally. Other labels on state transition arrows
describe conditions that trigger the transition.
[0255] Referring now to FIG. 19, the server is initially in a state
1902 where a new transaction is initiated via start message 1903.
This message includes transaction information including a
transaction identifier and a count of the blocks of data to be
transferred. The requester, initially in a wait state 1904 then
enters a data wait state 1905.
[0256] The server enters a data transmit state 1906 and transmits a
block of data 1907 and then enters a wait for acknowledgement state
1908. As the data is received, the requesters enters a data receive
state 1909 and when the data blocks is completely received it
enters an acknowledgement state 1910 and transmits an
Acknowledgement message 1911 to the server.
[0257] If there are more blocks to send, the server waits until
receiving an Acknowledgement message from the requester. When an
Acknowledgement message is received it sends the next block to the
requester and again waits for acknowledgement. The requester also
repeats the same cycle of states.
[0258] If the server detects a communications failure before
sending the last block, it enters a cancellation state 1912 wherein
the transaction is cancelled. Similarly, if the requester detects a
communications failure before receiving the last block it enters a
cancellation state 1913.
[0259] If there are no more blocks to send, the server commits to
the transaction and waits for the final Acknowledgement in state
1914. If there is a communications failure before the server
receives the final Acknowledgement message, it still commits to the
transaction but includes a report about the event to its credit
server in state 1915. This report serves two purposes. It will help
legitimize any claims by a user of having been billed for receiving
digital works that were not completely received. Also it helps to
identify repositories and communications lines that have suspicious
patterns of use and interruption. The server then enters its
completion state
[0260] On the requester side, when there are no more blocks to
receive, the requester commits to the transaction in state 1917. If
the requester detects a communications failure at this state, it
reports the failure to its credit server in state 1918, but still
commits to the transaction. When it has committed, it sends an
acknowledgement message to the server. The server then enters its
completion state 1919.
[0261] The key property is that both the server and the requester
cancel a transaction if it is interrupted before all of the data
blocks are delivered, and commits to it if all of the data blocks
have been delivered.
[0262] There is a possibility that the server will have sent all of
the data blocks (and committed) but the requester will not have
received all of them and will cancel the transaction. In this case,
both repositories will presumably detect a communications failure
and report it to their credit server. This case will probably be
rare since it depends on very precise timing of the communications
failure. The only consequence will be that the user at the
requester repository may want to request a refund from the credit
services--and the case for that refund will be documented by
reports by both repositories.
[0263] To prevent loss of data, the server should not delete any
transferred digital work until receiving the final acknowledgement
from the requester. But it also should not use the file. A well
known way to deal with this situation is called "two-phase commit"
or 2PC.
[0264] Two-phase commit works as follows. The first phase works the
same as the method described above. The server sends all of the
data to the requester. Both repositories mark the transaction (and
appropriate files) as uncommitted. The server sends a
ready-to-commit message to the requester. The requester sends back
an acknowledgement. The server then commits and sends the requester
a commit message. When the requester receives the commit message,
it commits the file.
[0265] If there is a communication failure or other crash, the
requester must check back with the server to determine the status
of the transaction. The server has the last word on this. The
requester may have received all of the data, but if it did not get
the final message, it has not committed. The server can go ahead
and delete files (except for transaction records) once it commits,
since the files are known to have been fully transmitted before
starting the 2PC cycle.
[0266] There are variations known in the art which can be used to
achieve the same effect. For example, the server could use an
additional level of encryption when transmitting a work to a
client. Only after the client sends a message acknowledging receipt
does it send the key. The client then agrees to pay for the digital
work. The point of this variation is that it provides a clear audit
trail that the client received the work. For trusted systems,
however, this variation adds a level of encryption for no real gain
in accountability.
[0267] The transactions for specific usage rights are now
discussed.
The Copy Transaction
[0268] A Copy transaction is a request to make one or more
independent copies of the work with the same or lesser usage
rights. Copy differs from the extraction right discussed later in
that it refers to entire digital works or entire folders containing
digital works. A copy operation cannot be used to remove a portion
of a digital work.
[0269] The requester sends the server a message to initiate the
Copy Transaction. This message indicates the work to be copied, the
version of the copy right to be used for the transaction, the
destination address information (location in a folder) for placing
the work, the file data for the work (including its size), and the
number of copies requested.
[0270] The repositories perform the common opening transaction
steps.
[0271] The server transmits the requested contents and data to the
client according to the transmission protocol. If a
Next-Set-Of-Rights has been provided in the version of the right,
those rights are transmitted as the rights for the work. Otherwise,
the rights of the original are transmitted. In any event, the
Copy-Count field for the copy of the digital work being sent right
is set to the number-of-copies requested.
[0272] The requester records the work contents, data, and usage
rights and stores the work. It records the date and time that the
copy was made in the properties of the digital work.
[0273] The repositories perform the common closing transaction
steps.
The Transfer Transaction
[0274] A Transfer transaction is a request to move copies of the
work with the same or lesser usage rights to another repository. In
contrast with a copy transaction, this results in removing the work
copies from the server.
[0275] The requester sends the server a message to initiate the
Transfer Transaction. This message indicates the work to be
transferred, the version of the transfer right to be used in the
transaction, the destination address information for placing the
work, the file data for the work, and the number of copies
involved.
[0276] The repositories perform the common opening transaction
steps.
[0277] The server transmits the requested contents and data to the
requester according to the transmission protocol. If a
Next-Set-Of-Rights has been provided, those rights are transmitted
as the rights for the work. Otherwise, the rights of the original
are transmitted. In either case, the Copy-Count field for the
transmitted rights is set to the number-of-copies requested.
[0278] The requester records the work contents, data, and usage
rights and stores the work.
[0279] The server decrements its copy count by the number of copies
involved in the transaction.
[0280] The repositories perform the common closing transaction
steps.
[0281] If the number of copies remaining in the server is now zero,
it erases the digital work from its memory.
The Loan Transaction
[0282] A loan transaction is a mechanism for loaning copies of a
digital work. The maximum duration of the loan is determined by an
internal parameter of the digital work. Works are automatically
returned after a predetermined time period.
[0283] The requester sends the server a message to initiate the
Transfer Transaction. This message indicates the work to be loaned,
the version of the loan right to be used in the transaction, the
destination address information for placing the work, the number of
copies involved, the file data for the work, and the period of the
loan.
[0284] The server checks the validity of the requested loan period,
and ends with an error if the period is not valid. Loans for a
loaned copy cannot extend beyond the period of the original loan to
the server.
[0285] The repositories perform the common opening transaction
steps.
[0286] The server transmits the requested contents and data to the
requester.
[0287] If a Next-Set-Of-Rights has been provided, those rights are
transmitted as the rights for the work. Otherwise, the rights of
the original are transmitted, as modified to reflect the loan
period.
[0288] The requester records the digital work contents, data, usage
rights, and loan period and stores the work.
[0289] The server updates the usage rights information in the
digital work to reflect the number of copies loaned out.
[0290] The repositories perform the common closing transaction
steps.
[0291] The server updates the usage rights data for the digital
work. This may preclude use of the work until it is returned from
the loan. The user on the requester platform can now use the
transferred copies of the digital work. A user accessing the
original repository cannot use the digital work, unless there are
copies remaining. What happens next depends on the order of events
in time.
[0292] Case 1. If the time of the loan period is not yet exhausted
and the requester sends the repository a Return message.
[0293] The return message includes the requester identification,
and the transaction ID.
[0294] The server decrements the copies-in-use field by the number
of copies that were returned. (If the number of digital works
returned is greater than the number actually borrowed, this is
treated as an error.) This step may now make the work available at
the server for other users.
[0295] The requester deactivates its copies and removes the
contents from its memory.
[0296] Case 2. If the time of the loan period is exhausted and the
requester has not yet sent a Return message.
[0297] The server decrements the copies-in-use field by the number
digital works that were borrowed.
[0298] The requester automatically deactivates its copies of the
digital work. It terminates all current uses and erases the digital
work copies from memory. One question is why a requester would ever
return a work earlier than the period of the loan, since it would
be returned automatically anyway. One reason for early return is
that there may be a metered fee which determines the cost of the
loan. Returning early may reduce that fee.
The Play Transaction
[0299] A play transaction is a request to use the contents of a
work. Typically, to "play" a work is to send the digital work
through some kind of transducer, such as a speaker or a display
device. The request implies the intention that the contents will
not be communicated digitally to any other system. For example,
they will not be sent to a printer, recorded on any digital medium,
retained after the transaction or sent to another repository.
[0300] This term "play" is natural for examples like playing music,
playing a movie, or playing a video game. The general form of play
means that a "player" is used to use the digital work. However, the
term play covers all media and kinds of recordings. Thus one would
"play" a digital work, meaning, to render it for reading, or play a
computer program, meaning to execute it. For a digital ticket the
player would be a digital ticket agent.
[0301] The requester sends the server a message to initiate the
play transaction. This message indicates the work to be played, the
version of the play right to be used in the transaction, the
identity of the player being used, and the file data for the
work.
[0302] The server checks the validity of the player identification
and the compatibility of the player identification with the player
specification in the right. It ends with an error if these are not
satisfactory.
[0303] The repositories perform the common opening transaction
steps.
[0304] The server and requester read and write the blocks of data
as requested by the player according to the transmission protocol.
The requester plays the work contents, using the player.
[0305] When the player is finished, the player and the requester
remove the contents from their memory.
[0306] The repositories perform the common closing transaction
steps.
The Print Transaction
[0307] A Print transaction is a request to obtain the contents of a
work for the purpose of rendering them on a "printer." We use the
term "printer" to include the common case of writing with ink on
paper. However, the key aspect of "printing" in our use of the term
is that it makes a copy of the digital work in a place outside of
the protection of usage rights. As with all rights, this may
require particular authorization certificates.
[0308] Once a digital work is printed, the publisher and user are
bound by whatever copyright laws are in effect. However, printing
moves the contents outside the control of repositories. For
example, absent any other enforcement mechanisms, once a digital
work is printed on paper, it can be copied on ordinary photocopying
machines without intervention by a repository to collect usage
fees. If the printer to a digital disk is permitted, then that
digital copy is outside of the control of usage rights. Both the
creator and the user know this, although the creator does not
necessarily give tacit consent to such copying, which may violate
copyright laws.
[0309] The requester sends the server a message to initiate a
Print, transaction. This message indicates the work to be played,
the identity of the printer being used, the file data for the work,
and the number of copies in the request.
[0310] The server checks the validity of the printer identification
and the compatibility of the printer identification with the
printer specification in the right. It ends with an error if these
are not satisfactory.
[0311] The repositories perform the common opening transaction
steps.
[0312] The server transmits blocks of data according to the
transmission protocol.
[0313] The requester prints the work contents, using the
printer.
[0314] When the printer is finished, the printer and the requester
remove the contents from their memory.
[0315] The repositories perform the common closing transaction
steps.
The Backup Transaction
[0316] A Backup transaction is a request to make a backup copy of a
digital work, as a protection against media failure. In the context
of repositories, secure backup copies differ from other copies in
three ways: (1) they are made under the control of a Backup
transaction rather than a Copy transaction, (2) they do not count
as regular copies, and (3) they are not usable as regular copies.
Generally, backup copies are encrypted.
[0317] Although backup copies may be transferred or copied,
depending on their assigned rights, the only way to make them
useful for playing, printing or embedding is to restore them.
[0318] The output of a Backup operation is both an encrypted data
file that contains the contents and description of a work, and a
restoration file with an encryption key for restoring the encrypted
contents. In many cases, the encrypted data file would have rights
for "printing" it to a disk outside of the protection system,
relying just on its encryption for security. Such files could be
stored anywhere that was physically safe and convenient. The
restoration file would be held in the repository. This file is
necessary for the restoration of a backup copy. It may have rights
for transfer between repositories.
[0319] The requester sends the server a message to initiate a
backup transaction. This message indicates the work to be backed
up, the version of the backup right to be used in the transaction,
the destination address information for placing the backup copy,
the file data for the work.
[0320] The repositories perform the common opening transaction
steps.
[0321] The server transmits the requested contents and data to the
requester. If a Next-Set-Of-Rights has been provided, those rights
are transmitted as the rights for the work. Otherwise, a set of
default rights for backup files of the original are transmitted by
the server.
[0322] The requester records the work contents, data, and usage
rights. It then creates a one-time key and encrypts the contents
file. It saves the key information in a restoration file.
[0323] The repositories perform the common closing transaction
steps.
[0324] In some cases, it is convenient to be able to archive the
large, encrypted contents file to secure offline storage, such as a
magneto-optical storage system or magnetic tape. This creation of a
non-repository archive file is as secure as the encryption process.
Such non-repository archive storage is considered a form of
"printing" and is controlled by a print right with a specified
"archive-printer." An archive-printer device is programmed to save
the encrypted contents file (but not the description file) offline
in such a way that it can be retrieved.
The Restore Transaction
[0325] A Restore transaction is a request to convert an encrypted
backup copy of a digital work into a usable copy. A restore
operation is intended to be used to compensate for catastrophic
media failure. Like all usage rights, restoration rights can
include fees and access tests including authorization checks.
[0326] The requester sends the server a message to initiate a
Restore transaction. This message indicates the work to be
restored, the version of the restore right for the transaction, the
destination address information for placing the work, and the file
data for the work.
[0327] The server verifies that the contents file is available
(i.e. a digital work corresponding to the request has been
backed-up.) If it is not, it ends the transaction with an
error.
[0328] The repositories perform the common opening transaction
steps.
[0329] The server retrieves the key from the restoration file. It
decrypts the work contents, data, and usage rights.
[0330] The server transmits the requested contents and data to the
requester according to the transmission protocol. If a
Next-Set-Of-Rights has been provided, those rights are transmitted
as the rights for the work. Otherwise, a set of default rights for
backup files of the original are transmitted by the server.
[0331] The requester stores the digital work.
[0332] The repositories perform the common closing transaction
steps.
The Delete Transaction
[0333] A Delete transaction deletes a digital work or a number of
copies of a digital work from a repository. Practically all digital
works would have delete rights.
[0334] The requester sends the server a message to initiate a
delete transaction. This message indicates the work to be deleted,
the version of the delete right for the transaction.
[0335] The repositories perform the common opening transaction
steps.
[0336] The server deletes the file, erasing it from the file
system.
[0337] The repositories perform the common closing transaction
steps.
The Directory Transaction
[0338] A Directory transaction is a request for information about
folders, digital works, and their parts. This amounts to roughly
the same idea as protection codes in a conventional file system
like TENEX, except that it is generalized to the full power of the
access specifications of the usage rights language.
[0339] The Directory transaction has the important role of passing
along descriptions of the rights and fees associated with a digital
work. When a user wants to exercise a right, the user interface of
his repository implicitly makes a directory request to determine
the versions of the right that are available. Typically these are
presented to the user--such as with different choices of billing
for exercising a right. Thus, many directory transactions are
invisible to the user and are exercised as part of the normal
process of exercising all rights.
[0340] The requester sends the server a message to initiate a
Directory transaction. This message indicates the file or folder
that is the root of the directory request and the version of the
directory right used for the transaction.
[0341] The server verifies that the information is accessible to
the requester.
[0342] In particular, it does not return the names of any files
that have a HIDE-NAME status in their directory specifications, and
it does not return the parts of any folders or files that have
HIDE-PARTS in their specification. If the information is not
accessible, the server ends the transaction with an error.
[0343] The repositories perform the common opening transaction
steps.
[0344] The server sends the requested data to the requester
according to the transmission protocol.
[0345] The requester records the data.
[0346] The repositories perform the common closing transaction
steps.
The Folder Transaction
[0347] A Folder transaction is a request to create or rename a
folder, or to move a work between folders. Together with Directory
rights, Folder rights control the degree to which organization of a
repository can be accessed or modified from another repository.
[0348] The requester sends the server a message to initiate a
Folder transaction. This message indicates the folder that is the
root of the folder request, the version of the folder right for the
transaction, an operation, and data. The operation can be one of
create, rename, and move file. The data are the specifications
required for the operation, such as a specification of a folder or
digital work and a name.
[0349] The repositories perform the common opening transaction
steps.
[0350] The server performs the requested operation--creating a
folder, renaming a folder, or moving a work between folders.
[0351] The repositories perform the common closing transaction
steps.
The Extract Transaction
[0352] A extract transaction is a request to copy a part of a
digital work and to create a new work containing it. The extraction
operation differs from copying in that it can be used to separate a
part of a digital work from d-blocks or shells that place
additional restrictions or fees on it. The extraction operation
differs from the edit operation in that it does not change the
contents of a work, only its embedding in d-blocks. Extraction
creates a new digital work.
[0353] The requester sends the server a message to initiate an
Extract transaction. This message indicates the part of the work to
be extracted, the version of the extract right to be used in the
transaction, the destination address information for placing the
part as a new work, the file data for the work, and the number of
copies involved.
[0354] The repositories perform the common opening transaction
steps.
[0355] The server transmits the requested contents and data to the
requester according to the transmission protocol. If a
Next-Set-Of-Rights has been provided, those rights are transmitted
as the rights for the new work. Otherwise, the rights of the
original are transmitted. The Copy-Count field for this right is
set to the number-of-copies requested.
[0356] The requester records the contents, data, and usage rights
and stores the work. It records the date and time that new work was
made in the properties of the work.
[0357] The repositories perform the common closing transaction
steps.
The Embed Transaction
[0358] An embed transaction is a request to make a digital work
become a part of another digital work or to add a shell d-block to
enable the adding of fees by a distributor of the work.
[0359] The requester sends the server a message to initiate an
Embed transaction. This message indicates the work to be embedded,
the version of the embed right to be used in the transaction, the
destination address information for placing the part as a work, the
file data for the work, and the number of copies involved.
[0360] The server checks the control specifications for all of the
rights in the part and the destination. If they are incompatible,
the server ends the transaction with an error.
[0361] The repositories perform the common opening transaction
steps.
[0362] The server transmits the requested contents and data to the
requester according to the transmission protocol. If a
Next-Set-Of-Rights has been provided, those rights are transmitted
as the rights for the new work. Otherwise, the rights of the
original are transmitted. The Copy-Count field for this right is
set to the number-of-copies requested.
[0363] The requester records the contents, data, and usage rights
and embeds the work in the destination file.
[0364] The repositories perform the common closing transaction
steps.
The Edit Transaction
[0365] An Edit transaction is a request to make a new digital work
by copying, selecting and modifying portions of an existing digital
work. This operation can actually change the contents of a digital
work. The kinds of changes that are permitted depend on the process
being used. Like the extraction operation, edit operates on
portions of a digital work. In contrast with the extract operation,
edit does not effect the rights or location of the work. It only
changes the contents. The kinds of changes permitted are determined
by the type specification of the processor specified in the rights.
In the currently preferred embodiment, an edit transaction changes
the work itself and does not make a new work. However, it would be
a reasonable variation to cause a new copy of the work to be
made.
[0366] The requester sends the server a message to initiate an Edit
transaction. This message indicates the work to be edited, the
version of the edit right to be used in the transaction, the file
data for the work (including its size), the process-ID for the
process, and the number of copies involved.
[0367] The server checks the compatibility of the process-ID to be
used by the requester against any process-ID specification in the
right. If they are incompatible, it ends the transaction with an
error.
[0368] The repositories perform the common opening transaction
steps.
[0369] The requester uses the process to change the contents of the
digital work as desired. (For example, it can select and duplicate
parts of it; combine it with other information; or compute
functions based on the information. This can amount to editing
text, music, or pictures or taking whatever other steps are useful
in creating a derivative work.)
[0370] The repositories perform the common closing transaction
steps.
[0371] The edit transaction is used to cover a wide range of kinds
of works. The category describes a process that takes as its input
any portion of a digital work and then modifies the input in some
way. For example, for text, a process for editing the text would
require edit rights. A process for "summarizing" or counting words
in the text would also be considered editing. For a music file,
processing could involve changing the pitch or tempo, or adding
reverberations, or any other audio effect. For digital video works,
anything which alters the image would require edit rights. Examples
would be colorizing, scaling, extracting still photos, selecting
and combining frames into story boards, sharpening with signal
processing, and so on.
[0372] Some creators may want to protect the authenticity of their
works by limiting the kinds of processes that can be performed on
them. If there are no edit rights, then no processing is allowed at
all. A processor identifier can be included to specify what kind of
process is allowed. If no process identifier is specified, then
arbitrary processors can be used. For an example of a specific
process, a photographer may want to allow use of his photograph but
may not want it to be colorized. A musician may want to allow
extraction of portions of his work but not changing of the
tonality.
Authorization Transactions
[0373] There are many ways that authorization transactions can be
defined. In the following, our preferred way is to simply define
them in terms of other transactions that we already need for
repositories. Thus, it is convenient sometimes to speak of
"authorization transactions," but they are actually made up of
other transactions that repositories already have.
[0374] A usage right can specify an authorization-ID, which
identifies an authorization object (a digital work in a file of a
standard format) that the repository must have and which it must
process. The authorization is given to the generic authorization
(or ticket) server of the repository which begins to interpret the
authorization.
[0375] As described earlier, the authorization contains a server
identifier, which may just be the generic authorization server or
it may be another server. When a remote authorization server is
required, it must contain a digital address. It may also contain a
digital certificate.
[0376] If a remote authorization server is required, then the
authorization process first performs the following steps:
[0377] The generic authorization server attempts to set up the
communications channel. (If the channel cannot be set up, then
authorization fails with an error.)
[0378] When the channel is set up, it performs a registration
process with the remote repository. (If registration fails, then
the authorization fails with an error.)
[0379] When registration is complete, the generic authorization
server invokes a "Play" transaction with the remote repository,
supplying the authorization document as the digital work to be
played, and the remote authorization server (a program) as the
"player." (If the player cannot be found or has some other error,
then the authorization fails with an error.)
[0380] The authorization server then "plays" the authorization.
This involves decrypting it using either the public key of the
master repository that issued the certificate or the session key
from the repository that transmitted it. The authorization server
then performs various tests. These tests vary according to the
authorization server. They include such steps as checking issue and
validity dates of the authorization and checking any hot-lists of
known invalid authorizations. The authorization server may require
carrying out any other transactions on the repository as well, such
as checking directories, getting some person to supply a password,
or playing some other digital work. It may also invoke some special
process for checking information about locations or recent events.
The "script" for such steps is contained within the authorization
server.
[0381] If all of the required steps are completed satisfactorily,
the authorization server completes the transaction normally,
signaling that authorization is granted.
The Install Transaction
[0382] An Install transaction is a request to install a digital
work as runnable software on a repository. In a typical case, the
requester repository is a rendering repository and the software
would be a new kind or new version of a player. Also in a typical
case, the software would be copied to file system of the requester
repository before it is installed.
[0383] The requester sends the server an Install message. This
message indicates the work to be installed, the version of the
Install right being invoked, and the file data for the work
(including its size).
[0384] The repositories perform the common opening transaction
steps.
[0385] The requester extracts a copy of the digital certificate for
the software. If the certificate cannot be found or the master
repository for the certificate is not known to the requester, the
transaction ends with an error.
[0386] The requester decrypts the digital certificate using the
public key of the master repository, recording the identity of the
supplier and creator, a key for decrypting the software, the
compatibility information, and a tamper-checking code. (This step
certifies the software.)
[0387] The requester decrypts the software using the key from the
certificate and computes a check code on it using a 1-way hash
function. If the check-code does not match the tamper-checking code
from the certificate, the installation transaction ends with an
error. (This step assures that the contents of the software,
including the various scripts, have not been tampered with.)
[0388] The requester retrieves the instructions in the
compatibility-checking script and follows them. If the software is
not compatible with the repository, the installation transaction
ends with an error. (This step checks platform compatibility.)
[0389] The requester retrieves the instructions in the installation
script and follows them. If there is an error in this process (such
as insufficient resources), then the transaction ends with an
error. Note that the installation process puts the runnable
software in a place in the repository where it is no longer
accessible as a work for exercising any usage rights other than the
execution of the software as part of repository operations in
carrying out other transactions.
[0390] The repositories perform the common closing transaction
steps.
The Uninstall Transaction
[0391] An Uninstall transaction is a request to remove software
from a repository. Since uncontrolled or incorrect removal of
software from a repository could compromise its behavioral
integrity, this step is controlled.
[0392] The requester sends the server an Uninstall message. This
message indicates the work to be uninstalled, the version of the
Uninstall right being invoked, and the file data for the work
(including its size).
[0393] The repositories perform the common opening transaction
steps.
[0394] The requester extracts a copy of the digital certificate for
the software. If the certificate cannot be found or the master
repository for the certificate is not known to the requester, the
transaction ends with an error.
[0395] The requester checks whether the software is installed. If
the software is not installed, the transaction ends with an
error.
[0396] The requester decrypts the digital certificate using the
public key of the master repository, recording the identity of the
supplier and creator, a key for decrypting the software, the
compatibility information, and a tamper-checking code. (This step
authenticates the certification of the software, including the
script for uninstalling it.)
[0397] The requester decrypts the software using the key from the
certificate and computes a check code on it using a 1-way hash
function. If the check-code does not match the tamper-checking code
from the certificate, the installation transaction ends with an
error. (This step assures that the contents of the software,
including the various scripts, have not been tampered with.)
[0398] The requester retrieves the instructions in the
uninstallation script and follows them. If there is an error in
this process (such as insufficient resources), then the transaction
ends with an error.
[0399] The repositories perform the common closing transaction
steps.
Distribution and Use Scenarios
[0400] To appreciate the robustness and flexibility of the present
invention, various distribution and use scenarios for digital works
are illustrated below. These scenarios are meant to be exemplary
rather than exhaustive.
Consumers as Unpaid Distributors
[0401] In this scenario, a creator distributes copies of his works
to various consumers. Each consumer is a potential distributor of
the work. If the consumer copies the digital work (usually for a
third party), a fee is collected and automatically paid to the
creator.
[0402] This scenario is a new twist for digital works. It depends
on the idea that "manufacturing" is just copying and is essentially
free. It also assumes that the consumers as distributors do not
require a fee for their time and effort in distributing the
work.
[0403] This scenario is performed as follows:
[0404] A creator creates a digital work. He grants a Copy right
with fees paid back to himself. If he does not grant an Embed
right, then consumers cannot use the mechanism to act as
distributors to cause fees to be paid to themselves on future
copies. Of course, they could negotiate side deals or trades to
transfer money on their own, outside of the system.
Paid Distributors
[0405] In another scenario, every time a copy of a digital work is
sold a fee is paid to the creator and also to the immediate
distributor.
[0406] This scenario does not give special status to any particular
distributor. Anyone who sells a document has the right to add a fee
to the sale price. The fee for sale could be established by the
consumer. It could also be a fixed nominal amount that is
contributed to the account of some charity.
[0407] This scenario is performed as follows:
[0408] A creator creates a digital work. He grants a Copy right
with fees to be paid back to himself. He grants an Embed right, so
that anyone can add shells to have fees paid to themselves.
[0409] A distributor embeds the work in a shell, with fees
specified to be paid back to himself. If the distributor is content
to receive fees only for copies that he sells himself, he grants an
Extract right on the shell.
[0410] When a consumer buys a copy from the distributor, fees are
paid both to the distributor and to the creator. If he chooses, the
consumer can extract the work from the distributor's shell. He
cannot extract it from the creator's shell. He can add his own
shell with fees to be paid to himself.
Licensed Distribution
[0411] In this scenario, a creator wants to protect the reputation
and value of his work by making certain requirements on its
distributors. He issues licenses to distributors that satisfy the
requirements, and in turn, promises to reward their efforts by
assuring that the work will not be distributed over competing
channels. The distributors incur expenses for selecting the digital
work, explaining it to buyers, promoting its sale, and possibly for
the license itself. The distributor obtains the right to enclose
the digital work in a shell, whose function is to permit the
attachment of usage fees to be paid to the distributor in addition
to the fees to be paid to the creator.
[0412] This differs from the previous scenario in that it precludes
the typical copy owner from functioning as a distributor, since the
consumer lacks a license to copy the document. Thus, a consumer
cannot make copies, even for free. All copies must come initially
from authorized distributors. This version makes it possible to
hold distributors accountable in some way for the sales and support
of the work, by controlling the distribution of certificates that
enable distributors to legitimately charge fees and copy owners to
make copies. Since licenses are themselves digital works, the same
mechanisms give the creators control over distributors by charging
for licenses and putting time limits on their validity.
[0413] This scenario is performed as follows:
[0414] A creator purchases a digital distribution license that he
will hand out to his distributors. He puts access requirements
(such as a personal license) on the Copy and Transfer rights on the
distribution license so that only he can copy or transfer it.
[0415] The creator also creates a digital work. He grants an Embed
right and a Copy right, both of which require the distribution
license to be exercised. He grants a Play right so that the work
can be played by anyone. He may optionally add a Transfer or Loan
right, so that end consumers can do some non-commercial exchange of
the work among friends.
[0416] A distributor obtains the distribution license and a number
of copies of the work. He makes copies for his customers, using his
distribution license.
[0417] A customer buys and uses the work. He cannot make new copies
because he lacks a distribution license.
Super Distributors
[0418] This is a variation on the previous scenarios. A distributor
can sell to anyone and anyone can sell additional copies, resulting
in fees being paid back to the creator. However, only licensed
distributors can add fees to be paid to themselves.
[0419] This scenario gives distributors the right to add fees to
cover their own advertising and promotional costs, without making
them be the sole suppliers. Their customers can also make copies,
thus broadening the channel without diminishing their revenues.
This is because distributors collect fees from copies of any copies
that they originally sold. Only distributors can add fees.
[0420] This scenario is performed similarly to the previous ones.
There are two key differences. (1) The creator only grants Embed
rights for people who have a Distribution license. This is done by
putting a requirement for a distributor's license on the Embed
right. Consequently, non-distributors cannot add their own fees.
(2) The Distributor does not grant Extract rights, so that
consumers cannot avoid paying fees to the Distributor if they make
subsequent copies. Consequently, all subsequent copies result in
fees paid to the Distributor and the Creator.
1-Level Distribution Fees
[0421] In this scenario, a distributor gets a fee for any copy he
sells directly. However, if one of his customers sells further
copies, he gets no further fee for those copies.
[0422] This scenario pays a distributor only for use of copies that
he actually sold.
[0423] This scenario is performed similarly to the previous ones.
The key feature is that the distributor creates a shell which
specifies fees to be paid to him. He puts Extract rights on the
shell. When a consumer buys the work, he can extract away the
distributor's shell. Copies made after that will not require fees
to be paid to the distributor.
Distribution Trees
[0424] In another scenario, distributors sell to other distributors
and fees are collected at each level. Every copy sold by any
distributor--even several d-blocks down in the chain--results in a
fee being paid back to all of the previous distributors.
[0425] This scenario is like a chain letter or value chain. Every
contributor or distributor along the way obtains fees, and is
thereby encouraged to promote the sale of copies of the digital
work.
[0426] This scenario is performed similarly to the previous ones.
The key feature is that the distributor creates a shell which
specifies fees to be paid to him. He does not grant Extract rights
on the shell. Consequently, all future copies that are made will
result in fees paid to him.
Weighted Distribution Trees
[0427] In this scenario, distributors make money according to a
distribution tree. The fee that they make depends on various
parameters, such as time since their sale or the number of
subsequent distributors.
[0428] This is a generalized version of the Distribution Tree
scenario, in that it tries to vary the fee to account for the
significance of the role of the distributor.
[0429] This scenario is similar to the previous one. The difference
is that the fee specification on the distributor's shell has
provisions for changes in prices. For example, there could be a fee
schedule so that copies made after the passage of time will require
lower fees to be paid to the distributor. Alternatively, the
distributor could employ a "best-price" billing option, using any
algorithm he chooses to determine the fee up to the maximum
specified in the shell.
Fees for Reuse
[0430] In this scenario, a first creator creates a work. It is
distributed by a first distributor and purchased by a second
creator. The second creator extracts a portion of the work and
embeds in it a new work distributed by a second distributor. A
consumer buys the new work from the second distributor. The first
creator receives fees from every transaction; the first distributor
receives fees only for his sale; the second creator and second
distributor receive fees for the final sale.
[0431] This scenario shows how that flexible automatic arrangements
can be set up to create automatic charging systems that mirror
current practice. This scenario is analogous to when an author pays
a fee to reuse a figure in some paper. In the most common case, a
fee is paid to the creator or publisher, but not to the bookstore
that sold the book.
[0432] The mechanisms for derived works are the same as those for
distribution.
Limited Reuse
[0433] In this scenario, several first creators create works. A
second creator makes a selection of these, publishing a collection
made up of the parts together with some new interstitial material.
(For example, the digital work could be a selection of music or a
selection of readings.) The second creator wants to continue to
allow some of the selected works to be extractable, but not the
interstitial material.
[0434] This scenario deals with fine grained control of the rights
and fees for reuse.
[0435] This scenario is performed as follows:
[0436] The first creators create their original works. If they
grant extraction and embedding rights, then the second creator can
include them in a larger collected work. The second creator creates
the interstitial material. He does grant an Extract right on the
interstitial material. He grants Extract rights on a subset of the
reused material. A consumer of the collection can only extract
portions that have that right. Fees are automatically collected for
all parts of the collection.
Commercial Libraries
[0437] Commercial libraries buy works with the right to loan. They
limit the loan period and charge their own fees for use. This
scenario deals with fees for loaning rather than fees for making
copies. The fees are collected by the same automatic
mechanisms.
[0438] The mechanisms are the same as previous scenarios except
that the fees are associated with the Loan usage right rather than
the Copy usage right.
Demo Versions
[0439] A creator believes that if people try his work that they
will want to buy it or use it. Consumers of his work can copy the
work for free, and play (or execute) a limited version of the work
for free, and can play or use the full featured version for a fee.
This scenario deals with fees for loaning rather than fees for
making copies. The fees are collected by the same automatic
mechanisms.
[0440] This scenario is performed as follows:
[0441] The creator creates a digital work and grants various rights
and fees. The creator grants Copy and Embed rights without a fee,
in order to ensure widespread distribution of the work. Another of
the rights is a limited play right with little or no fee attached.
For example, this right may be for playing only a portion of the
work. The play right can have various restrictions on its use. It
could have a ticket that limits the number of times it is used. It
could have internal restrictions that limit its functionality. It
could have time restrictions that invalidate the right after a
period of time or a period of use. Different fees could be
associated with other versions of the Play right.
Upgrading a Digital Work with a Vendor
[0442] A consumer buys a digital work together with an agreement
that he can upgrade to a new version at a later date for a modest
fee, much less than the usual purchase price. When the new version
becomes available, he goes to a qualified vendor to make the
transaction.
[0443] This scenario deals with a common situation in computer
software. It shows how a purchase may include future "rights." Two
important features of the scenario are that the transaction must
take place at a qualified vendor, and that the transaction can be
done only once per copy of the digital work purchased.
[0444] This scenario is performed as follows:
[0445] The creator creates a digital work, an upgrade ticket, and a
distribution license. The upgrade ticket uses the a generic ticket
agent that comes with repositories. As usual, the distribution
license does not have Copy or Transfer rights. He distributes a
bundled copies of the work and the ticket to his distributors as
well as distribution licenses.
[0446] The distributor sells the old bundled work and ticket to
customers.
[0447] The customer extracts the work and the ticket. He uses the
work according to the agreements until the new version becomes
available.
[0448] When the new work is ready, the creator gives it to
distributors. The new work has a free right to copy from a
distributor if a ticket is available.
[0449] The consumer goes to distributors and arranges to copy the
work. The transaction offers the ticket. The distributor's
repository punches the ticket and copies the new version to the
consumer's repository.
[0450] The consumer can now use the new version of the work.
Distributed Upgrading of Digital Works
[0451] A consumer buys a digital work together with an agreement
that he can upgrade to a new version at a later date for a modest
fee, much less than the usual purchase price. When the new version
becomes available, he goes to anyone who has the upgraded version
and makes the transaction.
[0452] This scenario is like the previous one in that the
transaction can only be done once per copy of the digital work
purchased, but the transaction can be accomplished without the need
to connect to a licensed vendor.
[0453] This scenario is similar to the previous one except that the
Copy right on the new work does not require a distribution license.
The consumer can upgrade from any repository having the new
version. He cannot upgrade more than once because the ticket cannot
work after it has been punched. If desired, the repository can
record the upgrade transaction by posting a zero cost bill to alert
the creator that the upgrade has taken place.
Limited Printing
[0454] A consumer buys a digital work and wants to make a few
ephemeral copies. For example, he may want to print out a paper
copy of part of a digital newspaper, or he may want to make a
(first generation) analog cassette tape for playing in his car. He
buys the digital work together with a ticket required for printing
rights.
[0455] This scenario is like the common practice of people making
cassette tapes to play in their car. If a publisher permits the
making of cassette tapes, there is nothing to prevent a consumer
from further copying the tapes. However, since the tapes are
"analog copies," there is a noticeable quality loss with subsequent
generations. The new contribution of the present invention is the
use of tickets in the access controls for the making of the analog
copies.
[0456] This scenario is performed as follows:
[0457] The creator sells a work together with limited printing
rights. The printing rights specify the kind of printer (e.g., a
kind of cassette recorder or a kind of desktop paper printer) and
also the kind of ticket required. The creator either bundles a
limited number of tickets or sells them separately. If the tickets
use the generic ticket agent, the consumer with the tickets can
exercise the right at his convenience.
Demand Publishing
[0458] Professors in a business school want to put together course
books of readings selected from scenario studies from various
sources. The bookstore wants to be able to print the books from
digital masters, without negotiating for and waiting for approval
of printing of each of the scenarios. The copyright holders of the
scenarios want to be sure that they are paid for every copy of
their work that is printed.
[0459] On many college campuses, the hassle of obtaining copy
clearances in a timely way has greatly reduced the viability of
preparing course books. Print shops have become much more cautious
about copying works in the absence of documented permission.
[0460] Demand Publishing is performed as follows: the creator sells
a work together with printing rights for a fee. There can be rights
to copy (distribute) the work between bookstore repositories, with
or without fee. The printing rights specify the kind of printer.
Whenever a bookstore prints one of the works (either standalone or
embedded in a collection), the fee is credited to the creator
automatically. To discourage unauthorized copying of the print
outs, it would be possible for the printer to print tracer messages
discretely on the pages identifying the printing transaction, the
copy number, and any other identifying information. The tracer
information could be secretly embedded in the text itself (encoded
in the grey scale) or hidden in some other way.
Metered Use and Multiple Price Packages
[0461] A consumer does not know what music to purchase until he
decides whether he likes it. He would like to be able to take it
home and listen to it, and then decide whether to purchase.
Furthermore, he would like the flexibility of paying less if he
listens to it very infrequently.
[0462] This scenario just uses the capability of the approach to
have multiple versions of a right on a digital work. Each version
of the right has its own billing scheme. In this scenario, the
creator of the work can offer the Copy right without fee, and defer
billing to the exercise of the Play right. One version of the play
right would allow a limited performance without fee--a right to
"demo". Another version of the right could have a metered rate, of
say $0.25 per hour of play. Another version could have a fee of
$15.00 for the first play, but no fee for further playing. When the
consumer exercises a play right, he specifies which version of the
right is being selected and is billed accordingly.
Fees for Font Usage
[0463] A designer of type fonts invests several months in the
design of special fonts. The most common way of obtaining revenue
for this work is to sell copies of the fonts to publishers for
unlimited use over unlimited periods of time. A font designer would
like to charge a rate that reflects the amount that the font is
used.
[0464] This scenario is performed as follows: the font designer
creates a font as a digital work. He creates versions of the Play
right that bill either for metered use or "per-use". Each version
of the play right would require that the player (a print layout
program) be of an approved category. The font designer assigns
appropriate fees to exercise the Copy right. When a publisher
client wants to use a font, he includes it as input to a layout
program, and is billed automatically for its use. In this way, a
publisher who makes little use of a font pays less than one who
uses it a lot.
Rational Database Usage Charges
[0465] Online information retrieval services typically charge for
access in a way that most clients find unpredictable and
uncorrelated to value or information use. The fee depends on which
databases are open, dial-up connect time, how long the searches
require, and which articles are printed out. There are no
provisions for extracting articles or photographs, no method for
paying to reuse information in new works, no distinction between
having the terminal sit idly versus actively searching for data, no
distinction between reading articles on the screen and doing
nothing, and higher rates per search when the centralized facility
is busy and slow servicing other clients. Articles can not be
offloaded to the client's machine for off-site search and printing.
To offer such billing or the expanded services, the service company
would need a secure way to account for and bill for how information
is used.
[0466] This scenario is performed as follows:
[0467] The information service bundles its database as files in a
repository. The information services company assigns different fees
for different rights on the information files. For example, there
could be a fee for copying a search database or a source file and a
different fee for printing. These fees would be in addition to fees
assigned by the original creator for the services. The fees for
using information would be different for using them on the
information service company's computers or the client's computers.
This billing distinction would be controlled by having different
versions of the rights, where the version for use on the service
company's computer requires a digital certificate held locally.
Fees for copying or printing files would be handled in the usual
way, by assigning fees to exercising those rights. The distinction
between searching and viewing information would be made by having
different "players" for the different functions. This distinction
would be maintained on the client's computers as well as the
service computers. Articles could be extracted for reuse under the
control of Extract and Embed rights. Thus, if a client extracts
part of an article or photograph, and then sells copies of a new
digital work incorporating it, fees could automatically be
collected both by the information service and earlier creators and
distributors of the digital work. In this way, the information
retrieval service could both offer a wider selection of services
and billing that more accurately reflects the client's use of the
information.
Print Spooling with Rights
[0468] In the simplest scenario, when a user wants to print a
digital document he issues a print command to the user interface.
If the document has the appropriate rights and the conditions are
satisfied, the user agrees to the fee and the document is printed.
In other cases, the printer may be on a remote repository and it is
convenient to spool the printing to a later time. This leads to
several issues. The user requesting the printing wants to be sure
that he is not billed for the printing until the document is
actually printed. Restated, if he is billed at the time the print
job is spooled but the job is canceled before printing is done, he
does not want to pay. Another issue is that when spooling is
permitted, there are now two times at which rights, conditions and
fees could be checked: the time at which a print job is spooled and
the time at which a print is made. As with all usage rights, it is
possible to have rights that expire and to have rights whose fee
depends on various conditions. What is needed is a means to check
rights and conditions at the time that printing is actually
done.
[0469] This scenario is performed as follows: A printing repository
is a repository with the usual repository characteristics plus the
hardware and software to enable printing. Suppose that a user logs
into a home repository and wants to spool print jobs for a digital
work at a remote printing repository. The user interface for this
could treat this as a request to "spool" prints. Underneath this
"spooling" request, however, are standard rights and requests. To
support such requests, the creator of the work provides a Copy
right, which can be used to copy the work to a printing repository.
In the default case, this Copy right would have no fees associated
for making the copy. However, the Next-Set-Of-Rights for the copy
would only include the Print rights, with the usual fees for each
variation of printing. This version of the Copy right could be
called the "print spooling" version of the Copy right. The user's
"spool request" is implemented as a Copy transaction to put a copy
of the work on the printing repository, followed by Print
transactions to create the prints of the work. In this way, the
user is only billed for printing that is actually done.
Furthermore, the rights, conditions and fees for printing the work
are determined when the work is about to be printed.
[0470] Thus, a system for enforcing the usage rights of digital
works is disclosed. While the embodiments disclosed herein are
preferred, it will be appreciate from this teaching that various
alternative, modifications, variations or improvements therein may
be made by those skilled in the art, which are intended to be
encompassed by the following claims.
APPENDIX A
Glossary
Authorization Repository:
[0471] A special type of repository which provides an authorization
service. An authorization may be specified by a usage right. The
authorization must be obtained before the right may be
exercised.
Billing Clearinghouse:
[0472] A financial institution or the like whose purpose is to
reconcile billing information received from credit servers. The
billing clearinghouse may generate bills to users or alternatively,
credit and debit accounts involved in the commercial
transactions.
Billing Transactions:
[0473] The protocol used by which a repository reports billing
information to a credit server.
Clearinghouse Transactions:
[0474] The protocol used between a credit server and a
clearinghouse.
Composite Digital Work:
[0475] A digital work comprised of distinguishable parts. Each of
the distinguishable parts is itself a digital work which has usage
rights attached.
Content:
[0476] The digital information (i.e. raw bits) representing a
digital work.
Copy Owner:
[0477] A term which refers to the party who owns a digital work
stored in a repository. In the typical case, this party has
purchased various rights to the document for printing, viewing,
transferring, or other specific uses.
Creator:
[0478] A term which refers to a party who produces a digital
work.
Credit Server:
[0479] A device which collects and reports billing information for
a repository. In many implementations, this could be built as part
of a repository. It requires a means for periodically communicating
with a billing clearinghouse.
Description Tree:
[0480] A structure which describes the location of content and the
usage rights and usage fees for a digital work. A description tree
is comprised of description blocks. Each description block
corresponds to a digital work or to an interest (typically a
revenue bearing interest) in a digital work.
Digital Work (Work):
[0481] Any encapsulated digital information. Such digital
information may represent music, a magazine or book, or a
multimedia composition. Usage rights and fees are attached to the
digital work.
Distributor:
[0482] A term which refers to a party who legitimately obtains a
copy of a digital work and offers it for sale.
Identification (Digital) Certificate:
[0483] A signed digital message that attests to the identity of the
possessor. Typically, digital certificates are encrypted in the
private key of a well-known master repository.
Master Repository:
[0484] A special type of repository which issues identification
certificates and distributes lists of repositories whose integrity
have been compromised and which should be denied access to digital
works (referred to as repository "hotlists".)
Public Key Encryption:
[0485] An encryption technique used for secure transmission of
messages on a communication channel. Key pairs are used for the
encryption and decryption of messages. Typically one key is
referred to as the public key and the other is the private key. The
keys are inverses of each other from the perspective of encryption.
Restated, a digital work that is encrypted by one key in the pair
can be decrypted only by the other.
Registration Transactions:
[0486] The protocol used between repositories to establish a
trusted session.
Rendering Repository:
[0487] A special type of repository which is typically coupled to a
rendering system. The rendering repository will typically be
embodied within the secure boundaries of a rendering system.
Rendering System:
[0488] The combination of a rendering repository and a rendering
device. Examples of a rendering systems include printing systems,
display systems, general purpose computer systems, video systems or
audio systems.
Repository:
[0489] Conceptually a set of functional specifications defining
core functionality in the support of usage rights. A repository is
a trusted system in that it maintains physical, communications and
behavioral integrity.
Requester Mode:
[0490] A mode of a repository where it is requesting access to a
digital work.
Revenue Owners:
[0491] A term which refers to the parties that maintain an interest
in collecting fees for document use or who stand to lose revenue if
illegitimate copies of the digital work are made.
Server Mode:
[0492] A mode of a repository where it is processing an incoming
request to access a digital work.
Shell Description Block:
[0493] A special type of description block designating an interest
in a digital work, but which does not add content. This will
typically be added by a distributor of a digital work to add their
fees.
Transactions: A term used to refer to the protocols by which
repositories communicate.
Usage Fees:
[0494] A fee charged to a requester for access to a digital work.
Usage fees are specified within the usage rights language.
Usage Rights:
[0495] A language for defining the manner in which a digital work
may be used or distributed, as well as any conditions on which use
or distribution is premised.
Usage Transactions:
[0496] A set of protocols by which repositories communicate in the
exercise of a usage rights. Each usage right has it's own
transaction steps.
* * * * *