ContentGuard Holdings, Inc. v. Google, Inc.

Filing 1

COMPLAINT FOR PATENT INFRINGEMENT against Google, Inc. ( Filing fee $ 400 receipt number 0540-4510268.), filed by ContentGuard Holdings, Inc.. (Attachments: # 1 Exhibit A, # 2 Exhibit B, # 3 Exhibit C, # 4 Exhibit D, # 5 Exhibit E, # 6 Exhibit F, # 7 Exhibit G, # 8 Exhibit H, # 9 Exhibit I, # 10 Exhibit J, # 11 Exhibit K, # 12 Civil Cover Sheet)(Baxter, Samuel)

Exhibit I

111111

1111111111111111111111111111111111111111111111111111111111111
US008393007B2

(54)

(75)

(73)

( *)

United States Patent

(10)

Stefik et al.

c12)

(45)

SYSTEM AND METHOD FOR DISTRIBUTING
DIGITAL CONTENT TO BE RENDERED IN
ACCORDANCE WITH USAGE RIGHTS
INFORMATION

(56)

Notice:

Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.C. 154(b) by 0 days.
This patent is subject to a terminal disclaimer.

References Cited

U.S. PATENT DOCUMENTS
4,817,140
5,204,961
5,390,297
6,135,646

Inventors: Mark J. Stefik, Portola Valley, CA (US);
Peter L. T. Pirolli, San Francisco, CA
(US)
Assignee: ContentGuard Holdings, Inc.,
Wilmington, DE (US)

Patent No.:
US 8,393,007 B2
Date of Patent:
*Mar. 5, 2013

A
A
A
A

3/1989
4/1993
2/1995
10/2000

Chandra eta!.
Barlow
Barber eta!.
Kahn et al.

FOREIGN PATENT DOCUMENTS

EP
EP

0398492 A2
0588415 A1

1111990
3/1994

OTHER PUBLICATIONS
Kohl, John T. et al., "The Evolution of the Kerberos Authentication
Service", Distributed Open Systems, IEEE, 1994, 18 pages.
Non-Final Office Action dated Jun. 12, 2008 cited in U.S. Appl. No.
111304,793.
Final Office Action dated Nov. 14, 2008 cited in U.S. Appl. No.
111304,793.

(Continued)
(21)

Appl. No.: 13/585,408

(22)

Filed:

(65)

Primary Examiner- Brandon Hoffman
(74) Attorney, Agent, or Firm- Marc S. Kaufman; Stephen
M. Hertzler; Reed Smith LLP

Aug. 14, 2012
Prior Publication Data

US 2012/0317658Al

Dec. 13, 2012

Related U.S. Application Data

(60)

Continuation of application No. 13/584,782, filed on
Aug. 13, 2012, which is a continuation of application
No. 11/304,793, filed on Dec. 16, 2005, now
abandoned, which is a division of application No.
11/135,352, filed on May 24, 2005, now Pat. No.
(Continued)

(51)
(52)
(58)

Int. Cl.
G06F 7104
(2006.01)
U.S. Cl. ......................................................... 726/29
Field of Classification Search ........................ None
See application file for complete search history.

(57)
ABSTRACT
Methods, apparatus, and media for distributing digital content to at least one recipient computing device to be rendered
by the at least one recipient computing device in accordance
with usage rights information. An exemplary method comprises determining, by at least one sending computing device,
if the at least one recipient computing device is trusted to
receive the digital content from the at least one sending computing device, sending the digital content, by the at least one
sending computing device, to the at least one recipient computing device only if the at least one recipient computing
device has been determined to be trusted to receive the digital
content from the at least one sending computing device, and
sending usage rights information indicating how the digital
content may be rendered by the at least one recipient computing device, the usage rights information being enforceable
by the at least on recipient computing device.
15 Claims, 13 Drawing Sheets

US 8,393,007 B2
Page 2

Related U.S. Application Data
7,266,529, which is a continuation of application No.
10/322,759, filed on Dec. 19, 2002, now Pat. No.
6,898,576, which is a continuation of application No.
09/778,001, filed on Feb. 7, 2001, now Pat. No. 6,708,
157, which is a division of application No. 08/967,084,
filed on Nov. 10, 1997, now Pat. No. 6,236,971, which
is a continuation of application No. 08/344,760, filed
on Nov. 23, 1994, now abandoned.

(56)

References Cited
OTHER PUBLICATIONS

Non-Final Office Action dated May 27, 2009 cited in U.S. Appl. No.
111304,793.
Final Office Action dated Jan. 22, 2010 cited in U.S. Appl. No.
111304,793.
Decision on Appeal dated Jun. 13, 2012 cited in U.S. Appl. No.
111304,793.

U.S. Patent

Mar.5,2013

US 8,393,007 B2

Sheet 1 of 13

FIG. 1
Creator Creates A
Digital Work

v-101

Usage Rights Attached To
Digital Work and
Deposited In Repository 1

v-1 02

Repository 21nitiates A
v-103
Session With Repository 1

Repository 2 Requests
Access To Digital Work For v-1 04
A Stated Purpose
Repository 1 Checks Usage
Rights of Digital Work for v-1 05
Determined If Access May
Be Granted

I

Actess Denied
Repository 1
Terminates Session
with Error

~106

Access Granted
Repository 1 Transmits
Digital Work To
Repository 2

Repository 1 and 2 Each
Generate Billing
Information And Transmit
To Credit Server

U.S. Patent

Mar.5,2013

US 8,393,007 B2

Sheet 2 of 13

FIG. 2

---

...........................

"" .....

"

--- ----

(

205'
l
I

'

'- ......

...., .......................

__ ......

_

---

-~

"-,.

{

,,~205

I

'v

.,..-.,

,_._.~

l

I
J

,.._l...,
l

Authorization
Repository

/....£..~"i,

'-

\

{

I

l 202

I

I

"-'"

\.

\
\

I

Repository

l

I
I

I

I

l

I
I
I

\\

..~205

)

I

/

)

\

l 201

Rendering
Repository

I
I

I

' , __ .....

I
{

I

l

FIG. 3
302 '\
(
.l..

{

I

/

Repository

" '\\

I

)

1
\

'..._ ... I

I

_.....- 301

Credit
Server

I

I

j

2~1

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I

.t

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'-

"""--·- ---

r--~

----··

r---·-...

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{

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.

-----·- ·---- --·----- ,

I
I

Billing
1
l Clearinghouse !
_,.;
I
1

303 _
__,.

t
~
~---------------~

/

304

203

U.S. Patent

Mar.5,2013

US 8,393,007 B2

Sheet 3 of 13

FIG. 4A
r------------------------,I

I
I
I

i
I

Printer
Repository

1

:

Print Device

I

:

L402

L403 .

L-----·------------,-----~
\

Repository

,_ 401

_/- 404

FIG. 48
/

---410

r------------------------J-----------1

I
I

I
I

I
I

I

414

s

411

412--..,,_
Display
Engine

\

I

I
I

I
I

I

Credit
Server

Display/
Execution
Repository

1--

;-413

I

Execution
Engine

I
I

I
I

I
I

L-----------------

------------------~

Repository

V

415
·

U.S. Patent

Mar.5,2013

US 8,393,007 B2

Sheet 4 of 13

FIG. 5
80,000

20,000

0

50,000

30,000

90,000

70,000

I

10,000

I

I
Story A

Ad

Story B

Story c

)

~

)

)

512

513

511

510

FIG. 6
10,000

0

30,000

25,000

1,500

Text

Photo

Graphics

Sidebar

)
614

)
615

)

)

616

617

U.S. Patent

Mar.5,2013

US 8,393,007 B2

Sheet 5 of 13

FIG. 7
Identifier

~

Starting Address

~

~

Rights Portion

~

Parent Pointer

~
_/-

Child Pointer

FIG. 8

702

_r- 703

length

700

701

704
705
706

_
Child Pointer
L----------'1r~ 700

Top

820

d~block

(Ad)

d-block
(Story B)

d-block
(Story C)

822

821

d-block
(Story A)

823

824

d-block

FIG. 9
821

925

d-block
(Text)

- 926

d-block
(Graphics)

d-block
{Sidebar)

-928

U.S. Patent

Mar.5,2013

Sheet 6 of 13

US 8,393,007 B2

FIG. 10
Right
Code

Status
Information

f

r

1050

1052

FIG. 14
Right

1451

Transactional
Component

-1450

Specification
Component

)
1453
1454

Fees I Incentives

Time

Control

1455

Copy Count

1457
Access

1456

U.S. Patent

Mar.5,2013

US 8,393,007 B2

Sheet 7 of 13

FIG. 11
Identifier (Magazine)
Starting Address (0)
Length {100}000)
Rights Portion
(PRINT~ VIEW)

root
d-block
1101

...,/

Parent Pointer
Child Pointers

f

f

l

Identifier (Article 1)

•

Identifier (Article 2)

Starting Address (0}

Starting Address (25~001)

Length (25,000)

Length (25,000)

Rights Portion
(PRINT} V! EW)

Rights Portion
(PRINT, VIEW)

Parent Pointer

Parent Pointer

Child Pointers

Child Pointers

l_ d-block
1102

d-block _)

f

1105

•

Identifier (Article 3)

Identifier (Article 4)

Starting Address {50)001)

Starting Address (75,001)

Length (25,000)

Length (25,000)

Rights Portion
(VIEW)

Rights Portion
{PRINT (Fee))

Parent Pointer

Parent Pointer

Child Pointers

Child Pointers

d-block_j
1103

d~block )
1104-

U.S. Patent

Mar.5,2013

US 8,393,007 B2

Sheet 8 of 13

FIG. 12
t

Clock

I

I
I

Processing
Element

I

Processor
Memory

t

I
t

I [-~~0=-_L~-1207
r---~~~-

)

L_

1205

----~---· ------

.

---~----

I

_j

External
Interface
)

1206

___

I

1203

t

1

1

:

Descriptor
Storage

Content
Storage

I

_-{--

1204

I

L-------------------J

FIG. 13
User

___...---1305

Interface
Repository Specific
Software
Function I Services

J-1304

Usage Transaction
Handlers

___...---1303

Core Repository
Services f Transaction
Handling

Identification
~

1302

Operating
System

,_,--1301

Certificates

1306
~

U.S. Patent

Mar.5,2013

Sheet 9 of 13

US 8,393,007 B2

FIG. 15
1501 ..--.... Digital Work Rights:"' (Rights*)
1502 - - Right: =(Right-Code {Copy-Count} {Control-spec} {Time-Spec}
{Access-Spec} {Fee.Spec}}
Right-Code:= Render-Code• Transport-Code • File-ManagementCode Derivative-Works-Code • Configuration-Code
1504 - - Render-Code: !::: [Play: {Player: Player-ID} • Print: {Printer: Printer-ID}]
1505 ......_Transport-Code:= {Copy • Transfer • Loan {Remaining-Rights:
Next-Set-of-Rights}] {(Next-Cop)t-Rights: Next-Set-of-Rights}}
1506 - - FHe-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}
1507-- Derivative-Works-Code: =[Extract •Embe<l Edit {Process:
Prooess-ID}] {Next-Copy-Rights:
Next-Set-of Rights}
1508 --Configuration-Code: =
Install • Unins1a!!
1509 - NexhSet-of-Rights: =
{(Add: Set-of-Rights}} {(Delete:
Set-of-Rights)} {(Replace: Set--of•Rlghts)} {(Keep: Set-of-Rights)}
151 0 --Copy-Count: "" (Copies:positive-integer : 0 ! Unlimited}
1511 ---Control-Spec: =
{Control: {Restrlctable : Unrestrictab!e}

1503--

{Unchargeable Chargeable})

1512-- Time-Spec:~ ({Fixed-Interval• Slld!ng-lntemt

Meter·Time}

Until: Expiration-Date)
1513 - - Fixed-Interval: =From: Start-Time
1514 ..-- Slidin~lnterval: =Interval: Usa-Duration
1515 --Meter-Time: =Time-Rernaining: Remaining--Use
1516 --Access-Spec: = ({SC: Secmity-Ciass} {Authorization: Auttlorlzation-ID*}
{Other-Authorization: Authorizalion·l D*} {Ticket: Ticket-10})
1517 --- Fee-Spec: ={Schedu!oo-Discount} Regular-Fee·Spec •Scheduled-Fee-Spec •
Markup-Spec
1518 --Scheduled-Discount:= Scheduled-Discount: (Scheduled-Discount:
(Time..Spec Percentage}*)
1519 ,.......__ Regu!ar-Fee-.Spec: = • Incentive:} [Per-Use-Spec Metered-Rate~
({Fee:
Spec i Best-Price-spec : Ca!I-For-Prtce-Spec]
{Min: Money-Unit Per: Time-Spec} {Max:
Mooey~Unit Per: Time-spec} To: Account·!D)
1520 -........ Per-Use-Spec: = Per-Use: Money-Unit "
·
1521 - - Metered-Rate-Spec: =
Metered: Money-Unit Per: Time-Spec
1522 - Best-Price-Spec: =
Best-Price: Money-unit Max: Money-Unit
1523- Call-For-Price-Spec:= Cell-For-Price
1524 - Scheduled-Fee-Spec: = {Schedule: (Time--Spec Regular-Fea-Specy)
1525 -Markup-Spec: ~ Markup: percentage To: AccounHD

U.S. Patent

Mar.5,2013

Sheet 10 of 13

FIG. 16 REPOSITORY~1

US 8,393,007 B2

REPOSITORY-2

1601
Generate Registration
Identifier

1602.

1605

Transmit Registration
Message

Decrypt Registration
Message
1.----.------l-1606
1---....l

Save Encrypted
Reposltory-1
Registration Identifier

_...---1611
...---------L--.

Decrypt Performance
Message

t-----,

t,__.:;__-r-----'

1607

Extract Reposrtory~1
Identifier

No

No
Generate Performance
Message

1.....-------......-----'161 0
No

L--~

Transmit Performance
Message

Yes
Transmit Nonce
Repository~1

Terminate Transaction

1616

Repository-2
Terminate Transaction

U.S. Patent

Mar.5,2013

US 8,393,007 B2

Sheet 11 of 13

FIG. 17
REPOS!TORY~1

REPOSITORY~2

1701
Create a Session Key Pair

-1704
Decrypt Second Key

1702
Encrypt Second Key Using
Public Key of Repository-2

1705
Generate Timestamp
Exchange Message

1703
Transmit Encrypted Second
Key To Repository*2

-1706
Transmit Timestamp
Exchange Message
To Repository~ 1

(1707
~----------~~

Generate Timestamp
Message

1708
Transmit Timestamp

Message To Repository-.2

1709
Note Current Time

1711
Compare Current Time With
Time From Repository-1

No

Yes
Terminate Transaction

Compute Adjusted
Time Delta

U.S. Patent

Mar.5,2013

US 8,393,007 B2

Sheet 12 of 13

FIG. 18
REQUESTER

SERVER

1801

Server Generates
Transaction Identifier

Tests Passed

1804
No

Tests Failed

-1809

1810 ~
Decrement Copy
~--<
Count For Right

Yes

1813

No

1805

1815

1817
1816

1819

Perform Usage
Transaction Steps

Decrement Copies In Use For
Right By Number In Request

For Metered Use, Subtract
Initiate End~Charge Financial..,__ _- - ! Elapsed Time From Remaining
Transaction to Confirm Billing
Use Time For Right

1818

U.S. Patent

Mar.5,2013

US 8,393,007 B2

Sheet 13 of 13

FIG. 19
SERVER
1912~

(Cancel)
Fail

More
Data

New
Transaction
I
I
I
I
I
I
I

19J2

Send
Next Data
)

More

1906:
Start

1903

L------~

I

l
I

Data

I
I
I
I
I

Data
1907

l
I

l
I

I
I
I
I
I
I

r---....l
I
I
I
I
I
I
I

1

I
I
I
I
I
I

I
1

l

I

i

I

I

_)1914
Commit Report

'--

To Credit Server

+~
I
I
I
l

f
Report Error

To Credit Server

~

Ack

I

l

Watt For Ack

i

No

I

;--1908

I

1915

t

Done
)

1916

I
1

l

Ack
Line

1901

1

··----·-·.··-·----····-·----l _____________ t···--------1--··-···-------··----------···-·· ··--···--··-·· ---- -1---·-----~--- ---

CUENT

L'1

l

I

Wait For

Transaction

)

'

I

j(
1913

(Cancel)
Fail

I

I

Ll

1909

I

I
I

Wait For
Data

f
+

I
I

I
I

1904
1905_/

l

~

I
I

1
I
I
I
I
I
I
I

Data
Received

No

More
Data

: 1916

: )
Commit Report
To Credit Server

,_J More
Data

I

~

)1918
Report Error
To Credit Server

Acknowledge /1910

v1919
Done

US 8,393,007 B2
1

2

SYSTEM AND METHOD FOR DISTRIBUTING
DIGITAL CONTENT TO BE RENDERED IN
ACCORDANCE WITH USAGE RIGHTS
INFORMATION

be made or which corrupt the output when copying is detected
have been employed. Another scheme causes software to
become disabled after a predetermined period of time has
lapsed. A technique used for workstation based software is to
require that a special hardware device must be present on the
workstation in order for the software to run, e.g., see U.S. Pat.
No. 4,932,054 entitled "Method and Apparatus for Protecting
Computer Software Utilizing Coded Filter Network in Conjunction with an Active Coded Hardware Device." Such
devices are provided with the software and are commonly
referred to as dongles.
Yet another scheme is to distribute software, but which
requires a "key" to enable 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.
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 data grams
are sent to a license control system over an appropriate communication facility. The license control system then checks
the datagram to determine if the datagram is from a valid
licensee. The license control system then sends a reply datagram to the license check monitor indicating denial or
approval of usage. The license control system will deny usage
in the event that request datagrams go unanswered after a
predetermined period of time (which may indicate an unauthorized attempt to use the licensed product). In this system,
usage is managed at a central location by the response datagrams. So for example if license fees have not been paid,
access to the licensed product is terminated.
It is argued by Griswold that the described system is advantageous because it can be implemented entirely in software.
However, the system described by Griswold has limitations.
An important limitation is that during the use of the licensed
product, the user must always be coupled to an appropriate
communication facility in order to send and receive datagrams. This creates a dependency on the communication
facility. So if the communication facility is not available, the
licensed product carmot be used. Moreover, some party must
absorb the cost of communicating with the license server.
A system for controlling the distribution of digitally
encoded books is embodied in a system available from VPR
Systems, LTD. of St. Louis, Miss. The VPR system is selfcontained and is comprised of: (1) point of sale kiosks for
storing and downloading ofbooks, (2) personal storage mediurns (cartridges) to which the books are downloaded, and (3)
readers for viewing the book. In a purchase transaction, a
purchaser will purchase a voucher card representing the
desired book. The voucher will contain sufficient information
to identify the book purchased and perhaps some demographic information relating to the sales transaction. To
download the book, the voucher and the cartridge are inserted
into the kiosk.
The VPR system may also be used as a library. In such an
embodiment, the kiosk manages the number of"copies" that
may be checked out at one time. Further, the copy of the book
is erased from the user's cartridge after a certain check-out

CROSS REFERENCE TO RELATED
APPLICATIONS
This application is a continuation of U.S. application Ser.
No. 13/584,782, filed Aug. 13, 2012, which is a continuation
of U.S. application Ser. No. 11/304,793, filed Dec. 16, 2005,
which is a divisional ofU.S. application Ser. No. 11/135,352,
filed May 24, 2005, now U.S. Pat. No. 7,266,529, which is a
continuation of U.S. application Ser. No. 10/322,759, filed
Dec. 19, 2002, now U.S. Pat. No. 6,898,576, which is a
continuation of U.S. application Ser. No. 09/778,001, filed
Feb. 7, 2001, now U.S. Pat. No. 6,708,157, which is a divisional ofU.S. application Ser. No. 08/967,084, filed Nov. 10,
1997,nowU.S. Pat. No. 6,236,971, which is a continuation of
U.S. application Ser. No. 08/344,760, filed Nov. 23, 1994,
now abandoned, the entire disclosures of all of which are
hereby incorporated by reference herein.

10

15

20

FIELD OF THE INVENTION
25

The present invention relates to the field of distribution and
usage rights enforcement for digitally encoded works.
BACKGROUND OF THE INVENTION
30

A fundamental issue facing the publishing and information
industries as they consider electronic publishing is how to
prevent the unauthorized and unaccounted distribution or
usage of electronically published materials. Electronically
published materials are typically distributed in a digital form
and recreated on a computer based system having the capability to recreate the materials. Audio and video recordings,
software, books and multimedia works are all being electronically published. Companies in these industries receive royalties for each accounted for delivery of the materials, e.g. the
sale of an audio CD at a retail outlet. Any unaccounted distribution of a work results in an unpaid royalty (e.g. copying
the audio recording CD to another digital medium.)
The ease in which electronically published works can be
"perfectly" reproduced and distributed is a major concern.
The transmission of digital works over networks is commonplace. One such widely used network is the Internet. The
Internet is a widespread network facility by which computer
users in many universities, corporations and government entities communicate and trade ideas and information. Computer
bulletin boards found on the Internet and commercial networks such as CompuServ and Prodigy allow for the posting
and retrieving of digital information. Information services
such as Dialog and LEXIS/NEXIS provide databases of current information on a wide variety of topics. Another factor
which will exacerbate the situation is the development and
expansion of the National Information Infrastructure (the
Nil). It is anticipated that, as the Nil grows, the transmission
of digital works over networks will increase many times over.
It would be desirable to utilize the Nil for distribution of
digital works without the fear of widespread unauthorized
copying.
The most straightforward way to curb unaccounted distribution is to prevent unauthorized copying and transmission.
For existing materials that are distributed in digital form,
various safeguards are used. In the case of software, copy
protection schemes which limit the number of copies that can

35

40

45

50

55

60

65

US 8,393,007 B2
3

4

time has expired. However, individuals cannot loan books
because the cartridges may only be used with the owner's
reader.
The foregoing distribution and protection schemes operate
in part by preventing subsequent distribution of the work.
While this certainly prevents unauthorized distributions, it
does so by sacrificing the potential for subsequent revenue
bearing uses. For example, it may be desirable to allow the
lending of a purchased work to permit exposure of the work to
potential buyers. Another example would be to permit the
creation of a derivative work for a fee. Yet another example
would be to permit copying the work for a fee (essentially
purchasing it). Thus, it would be desirable to provide flexibility in how the owner of a digital work may allow it to be
distributed.
While flexibility in distribution is a concern, the owners of
a work want to make sure they are paid for such distributions.
In U.S. Pat. No. 4,977,594 to Shear, entitled "Database Usage
Metering and Protection System and Method," a system for
metering and billing for usage of information distributed on a
CD-ROM is described. The system requires the addition of a
billing module to the computer system. The billing module
may operate in a number of different ways. First, it may
periodically communicate billing data to a central billing
facility, whereupon the user may be billed. Second, billing
may occur by disconnecting the billing module and the user
sending it to a central billing facility where the data is read and
a user bill generated.
U.S. Pat. No. 5,247,575, Sprague eta!., 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. Ifthe central accounting facility has not
issued a new key for a particular user station, the station is
unable to retrieve information from the system when the key
is changed.
A system available from Wave Systems Corp. of Princeton,
N.Y., provides for metering of software usage on a personal
computer. The system is installed onto a computer and collects information on what software is in use, encrypts it and
then transmits the information to a transaction center. From
the transaction center, a bill is generated and sent to the user.
The transaction center also maintains customer accounts so
that licensing fees may be forwarded directly to the software
providers. Software operating under this system must be
modified so that usage can be accounted.
Known techniques for billing do not provide for billing of
copies made of the work. For example, if data is copied from
the CD-ROM described in Shear, any subsequent use of the
copy of the information cannot be metered or billed. In other
words, the means for billing runs with the media rather than
the underlying work. It would be desirable to have a distribution system where the means for billing is always transported
with the work.

rights from a grammar, the usage rights specifYing a manner
of use indicating purposes for which the digital content is
used and/or distributed by an authorized party; associating
the usage rights with a digital content; processing a usage
transaction specifying the usage rights to determine if access
to the digital content is granted; and storing the usage rights in
a distributed repository. The usage rights also specifY one or
more conditions which must be satisfied before the manner of
use is exercised. The creating includes selecting symbols
from a first set of predetermined symbols to define a valid
sequence of symbols to indicate the manner of use, selecting
one or more symbols from a second set of predetermined
symbols to define a valid sequence of symbols to indicate the
conditions.
In further embodiments, a system for controlling the distribution and use of digital works using digital tickets is
disclosed. A ticket is an indicator that the ticket holder has
already paid for or is otherwise entitled to some specified
right, product or service. In the present invention, a "digital
ticket" is used to enable the ticket holder to exercise usage
rights specifying the requirement of the digital ticket. Usage
rights are used to define how a digital work may be used or
distributed. Specific instances of usage rights are used to
indicate a particular manner of use or distribution. A usage
right may specify a digital ticket which must be present before
the right may be exercised. For example, a digital ticket may
be specified in a Copy right of a digital work, so that exercise
of the Copy right requires the party that desires a copy of the
digital work be in possession of the necessary digital ticket.
After a copy of the digital work is successfully sent to the
requesting party, the digital ticket is "punched" to indicate
that a copy of the digital work has been made. When the ticket
is "punched" a predetermined number of times, it may no
longer be used.
Digital works are stored in repositories. Repositories
enforce the usage rights for digital works. Each repository has
a "generic ticket agent" which punches tickets. In some
instances only the generic ticket agent is necessary. In other
instances, punching by a "special ticket agent" residing on
another repository may be desired. Punching by a "special
ticket agent" enables greater security and control of the digital
work. For example, it can help prevent digital ticket forgery.
Special ticket agents are also useful in situations where an
external database needs to be updated or checked.
A digital ticket is merely an instance of a digital work.
Thus, a digital ticket may be distributed among repositories in
the same fashion as other digital works.
A digital ticket may be used in many commercial scenarios
such as in the purchase of software and prepaid upgrades. A
digital ticket may also be used to limit the number of times
that a right may be exercised. For example, a user may purchase a copy of a digital work, along with the right to make up
to 5 Copies. In this case, the Copy right would have associated
therewith a digital ticket that can be punched up to 5 times.
Other such commercial scenarios will become apparent from
the detailed description.

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SUMMARY OF THE INVENTION
65

A method, system and software for associating usage rights
with digital content is provided, including creating usage

BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart illustrating a simple instantiation of
the operation of the currently preferred embodiment of the
present invention.
FIG. 2 is a block diagram illustrating the various repository
types and the repository transaction flow between them in the
currently preferred embodiment of the present invention.

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FIG. 3 is a block diagram of a repository coupled with a
credit server in the currently preferred embodiment of the
present invention.
FIGS. 4a and 4b are examples of rendering systems as may
be utilized in the currently preferred embodiment of the
present invention.
FIG. 5 illustrates a contents file layout for a digital work as
may be utilized in the currently preferred embodiment of the
present invention.
FIG. 6 illustrates a contents file layout for an individual
digital work of the digital work of FIG. 5 as may be utilized in
the currently preferred embodiment of the present invention.
FIG. 7 illustrates the components of a description block of
the currently preferred embodiment of the present invention.
FIG. 8 illustrates a description tree for the contents file
layout of the digital work illustrated in FIG. 5.
FIG. 9 illustrates a portion of a description tree corresponding to the individual digital work illustrated in FIG. 6.
FIG. 10 illustrates a layout for the rights portion of a
description block as may be utilized in the currently preferred
embodiment of the present invention.
FIG. 11 is a description tree wherein certain d-blocks have
PRINT usage rights and is used to illustrate "strict" and
"lenient" rules for resolving usage rights conflicts.
FIG. 12 is a block diagram of the hardware components of
a repository as are utilized in the currently preferred embodiment of the present invention.
FIG. 13 is a block diagram of the functional (logical)
components of a repository as are utilized in the currently
preferred embodiment of the present invention.
FIG. 14 is diagram illustrating the basic components of a
usage right in the currently preferred embodiment of the
present invention.
FIG. 15 lists the usage rights grammar of the currently
preferred embodiment of the present invention.
FIG. 16 is a flowchart illustrating the steps of certificate
delivery, hotlist checking and performance testing as performed in a registration transaction as may be performed in
the currently preferred embodiment of the present invention.
FIG. 17 is a flowchart illustrating the steps of session
information exchange and clock synchronization as may be
performed in the currently preferred embodiment of the
present invention, after each repository in the registration
transaction has successfully completed the steps described in
FIG. 16.
FIG. 18 is a flowchart illustrating the basic flow for a usage
transaction, including the common opening and closing step,
as may be performed in the currently preferred embodiment
of the present invention.
FIG. 19 is a state diagram of server and client repositories
in accordance with a transport protocol followed when moving a digital work from the server to the client repositories, as
may be performed in the currently preferred embodiment of
the present invention.

Keeping an unlimited supply of virtual copies on hand
requires essentially no more space than keeping one copy on
hand. The digital medium also lowers the costs of alteration,
reuse and billing.
There is a market for digital works because creators are
strongly motivated to reuse portions of digital works from
others rather than creating their own completely. This is
because it is usually so much easier to use an existing stock
photo or music clip than to create a new one from scratch.
Herein the terms "digital work", "work" and "content"
refer to any work that has been reduced to a digital representation. This would include any audio, video, text, or multimedia work and any accompanying interpreter (e.g. software)
that may be required for recreating the work. The term composite work refers to a digital work comprised of a collection
of other digital works. The term "usage rights" or "rights" is
a term which refers to rights granted to a recipient of a digital
work. Generally, these rights define how a digital work can be
used and if it can be further distributed. Each usage right may
have one or more specified conditions which must be satisfied
before the right may be exercised. Appendix 1 provides a
Glossary of the terms used herein.
A key feature of the present invention is that usage rights
are permanently "attached" to the digital work. Copies made
of a digital work will also have usage rights attached. Thus,
the usage rights and any associated fees assigned by a creator
and subsequent distributor will always remain with a digital
work.
The enforcement elements of the present invention are
embodied in repositories. Among other things, repositories
are used to store digital works, control access to digital works,
bill for access to digital works and maintain the security and
integrity of the system.
The combination of attached usage rights and repositories
enable distinct advantages over prior systems. As noted in the
prior art, payment of fees are primarily for the initial access.
In such approaches, once a work has been read, computational control over that copy is gone. Metaphorically, "the
content genie is out of the bottle and no more fees can be
billed." In contrast, the present invention never separates the
fee descriptions from the work. Thus, the digital work genie
only moves from one trusted bottle (repository) to another,
and all uses of copies are potentially controlled and billable.
FIG. 1 is a high level flowchart omitting various details but
which demonstrates the basic operation of the present invention. Referring to FIG. 1, a creator creates a digital work, step
101. The creator will then determine appropriate usage rights
and fees, attach them to the digital work, and store them in
Repository 1, step 102. The determination of appropriate
usage rights and fees will depend on various economic factors. The digital work remains securely in Repository 1 until
a request for access is received. The request for access begins
with a session initiation by another repository. Here a Repository 2 initiates a session with Repository 1, step 103. As will
be described in greater detail below, this session initiation
includes steps which 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

DETAILED DESCRIPTION OF THE PREFERRED
EMBODIMENT

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Overview
A system for controlling use and distribution of digital
works is disclosed. The present invention is directed to supporting commercial transactions involving digital works. The
transition to digital works profoundly and fundamentally
changes how creativity and commerce can work. It changes
the cost of transporting or storing works because digital property is almost "massless." Digital property can be transported
at electronic speeds and requires almost no warehousing.

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the digital work and if all conditions associated with the right
are satisfied. If the access is denied, repository 1 terminates
the session with an error message, step 106. If access is
granted, repository 1 transmits the digital work to repository
2, step 107. Once the digital work has been transmitted to
repository 2, repository 1 and 2 each generate billing information for the access which is transmitted to a credit server,
step 108. Such double billing reporting is done to insure
against attempts to circumvent the billing process.
FIG. 2 illustrates the basic interactions between repository
types in the present invention. As will become apparent from
FIG. 2, the various repository types will serve different functions. It is fundamental that repositories will share a core set
of functionality which will enable secure and trusted communications. Referring to FIG. 2, a repository 201 represents the
general instance of a repository. The repository 201 has two
modes of operation; a server mode and a requester mode.
When in the server mode, the repository will be receiving and
processing access requests to digital works. When in the
requester mode, the repository will be initiating requests to
access digital works. Repository 201 is general in the sense
that 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.
Communication with an authorization repository 202 may
occur when a digital work being accessed has a condition
requiring an authorization. Conceptually, an authorization is
a digital certificate such that possession of the certificate is
required to gain access to the digital work. An authorization is
itself a digital work that can be moved between repositories
and subjected to fees and usage rights conditions. An authorization may be required by both repositories involved in an
access to a digital work.
Communication with a rendering repository 203 occurs in
connection with the rendering of a digital work. As will be
described in greater detail below, a rendering repository is
coupled with a rendering device (e.g. a printer device) to
comprise a rendering system.
Communication with a master repository 205 occurs in
connection with obtaining an identification certificate. Identification certificates are the means by which a repository is
identified as "trustworthy". The use of identification certificates is described below with respect to the registration transaction.
FIG. 3 illustrates the repository 201 coupled to a credit
server 301. The credit server 301 is a device which accumulates billing information for the repository 201. The credit
server 301 communicates with repository 201 via billing
transactions 302 to record billing transactions. Billing transactions are reported to a billing clearinghouse 303 by the
credit server 301 on a periodic basis. The credit server 301
communicates to the billing clearinghouse 303 via clearinghouse transactions 304. The clearinghouse transactions 304
enable a secure and encrypted transmission of information to
the billing clearinghouse 303.

a repository. The coupling of a rendering repository with the
rendering device may occur in a manner suitable for the type
of rendering device.
FIG. 4a illustrates a printer as an example of a rendering
system. Referring to FIG. 4, printer system 401 has contained
therein a printer repository 402 and a print device 403. It
should be noted that the dashed line defining printer system
401 defines a secure system boundary. Communications
within the boundary is assumed to be secure. Depending on
the security level, the boundary also represents a barrier
intended to provide physical integrity. The printer repository
402 is an instantiation of the rendering repository 205 of FIG.
2. The printer repository 402 will in some instances contain an
ephemeral copy of a digital work which remains until it is
printed out by the print engine 403. In other instances, the
printer repository 402 may contain digital works such as
fonts, which will remain and can be billed based on use. This
design assures that all communication lines between printers
and printing devices are encrypted, unless they are within a
physically secure boundary. This design feature eliminates a
potential "fault" point through which the digital work could
be improperly obtained. The printer device 403 represents the
printer components used to create the printed output.
Also illustrated in FIG. 4a is the repository 404. The
repository 404 is coupled to the printer repository 402. The
repository 404 represents an external repository which contains digital works.
FIG. 4b is an example of a computer system as a rendering
system. A computer system may constitute a "multi-function" device since it may execute digital works (e.g. software
programs) and display digital works (e.g. a digitized photograph). Logically, each rendering device can be viewed as
having 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/executionrepository 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/executionrepository 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.

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Rendering Systems
A rendering system is generally defined as a system comprising a repository and a rendering device which can render
a digital work into its desired form. Examples of a rendering
system may be a computer system, a digital audio system, or
a printer. A rendering system has the same security features as

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Structure of Digital Works
Usage rights are attached directly to digital works. Thus, it
is important to understand the structure of a digital work. The
structure of a digital work, in particular composite digital
works, may be naturally organized into an acyclic structure
such as a hierarchy. For example, a magazine has various
articles and photographs which may have been created and
are owned by different persons. Each of the articles and
photographs may represent a node in a hierarchical structure.
Consequently, controls, i.e. usage rights, may be placed on
each node by the creator. By enabling control and fee billing
to be associated with each node, a creator of a work can be
assured that the rights and fees are not circumvented.
In the currently preferred embodiment, the file information
for a digital work is divided into two files: a "contents" file
and a "description tree" file. From the perspective of a repository, the "contents" file is a stream of addressable bytes whose
format depends completely on the interpreter used to play,
display or print the digital work. The description tree file
makes it possible to examine the rights and fees for a work
without reference to the content of the digital work. It should
be noted that the term description tree as used herein refers to

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any type of acyclic structure used to represent the relationship
between the various components of a digital work.
FIG. 5 illustrates the layout of a contents file. Referring to
FIG. 5, a digital work 509 is comprised of story A 510,
advertisement 511, story B 512 and story C 513. It is assumed
that the digital work is stored starting at a relative address of
0. Each of the parts of the digital work are stored linearly so
that story A 510 is stored at approximately addresses 0-30,
000, advertisement 511 at addresses 30,001-40,000, story B
512 at addresses 40,001-60,000 and story C 513 at addresses
60,001-85K. 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).
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.
A special type of d-block is a "shell" d-block. A shell
d-block adds no new content beyond the content of its parts.
A shell d-block is used to add rights and fee information,
typically by distributors of digital works.
FIG. 8 illustrates a description tree for the digital work of
FIG. 5. Referring to FIG. 8, a top d-block 820 for the digital
work points to the various stories and advertisements contained therein. Here, the top d-block 820 points to d-block821
(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).
The portion of the description tree for Story A 510 is
illustrated in FIG. 9. D-b lock 925 represents text 614, d-block
926 represents photo 615, d-block 927 represents graphics
616 by and d-block 928 represents sidebar 617.
The rights portion 704 of a descriptor block is further
illustrated in FIG. 10. FIG. 10 illustrates a structure which is
repeated in the rights portion 704 for each right. Referring to
FIG.10, each right will have aright code field 1001 and status
information field 1002. The right code field 1001 will contain
a unique code assigned to a right. The status information field
1002 will contain information relating to the state of a right
and the digital work. Such information is indicated below in
Table 1. The rights as stored in the rights portion 304 may
typically be in numerical order based on the right code.

The approach for representing digital works by separating
description data from content assumes that parts of a file are
contiguous but takes no position on the actual representation
of content. In particular, it is neutral to the question of whether
content representation may take an object oriented approach.
It would be natural to represent content as objects. In principle, it may be convenient to have content objects that
include the billing structure and rights information that is
represented in the d-blocks. Such variations in the design of
the representation are possible and are viable alternatives but
may introduce processing overhead, e.g. the interpretation of
the objects.

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TABLE 1
15

DIGITAL WORK STATE INFORMATION
Property

Value

Use

Copies-inUse

Number

Loan-Period

Time-Units

Loaner-Copy

Boolean

RemainingTime
DocumentDescr

Time-Units

RevenueOwner

RO-Descr

A counter of the number of copies of a
work that are in use. Incremented when
another copy is used; decremented when
use is completed.
Indicator of the maximwn nwnber of
time-nnits that a docwnent can be
loaned out
Indicator that the current work is a
loaned out copy of an authorized digital
work.
Indicator of the remaining time of use
on a metered docwnent right.
A string containing various identifYing
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
nwnber, and so on.
A handle identifYing a revenue owner
for a digital work. This is used for
reporting usage fees.
The date tbat the digital work was
published.
A list of events recording the repostories
and dates for operations that copy,
transfer, backup, or restore a digital
work.

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String

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35 PublicationDate
History-list

Date-Descr
History-Rec

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Digital works are stored in a repository as part of a hierarchical file system. Folders (also termed directories and subdirectories) 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

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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 cam10t grant more rights than they
have.

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The attachment of usage rights into a digital work may
occur ina variety of ways. If the usage rights will be the same
for an entire digital work, they could be attached when the
digital work is processed for deposit in the digital work server.
In the case of a digital work having different usage rights for
the various components, this can be done as the digital work
is being created. An authoring tool or digital work assembling
tool could be utilized which provides for an automated process of attaching the usage rights.
As will be described below, when a digital work is copied,
transferred or loaned, a "next set of rights" can be specified.
The "next set of rights" will be attached to the digital work as
it is transported.
Resolving Conflicting Rights
Because each part of a digital work may have its own usage
rights, there will be instances where the rights of a "contained
part" are different from its parent or container part. As a
result, conflict rules must be established to dictate when and
how a right may be exercised. The hierarchical structure of a
digital work facilitates the enforcement of such rules. A
"strict" rule would be as follows: a right for a part in a digital
work is sanctioned if and only if it is sanctioned for the part,
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.
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.
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 childd-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.
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.
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.

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, commnnications integrity, and behavioral integrity.
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.
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.
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.
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

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Repositories
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

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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.
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.
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.
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.
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.
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.
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.

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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.
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.
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.
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

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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.
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.
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.

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TABLE2

a computer system. The user interface may be combination of
a display, keyboard, cursor control device and software
executing on the computer system.
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.

REPOSITORY SECURITY LEVELS
Level Description of Security
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Open system. Docwnent transmission is nnencrypted. No digital
certificate is required for identification. The secmity 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 nnauthorized programs from
running and accessing or copying files. The system does not
prevent the use of removable storage and does not encrypt stored
files.
Minimal security. Like the previous class except that stored files
are minimally encrypted, including ones on removable storage.
Basic secmity. 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 nwnber is unforgeable.
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 nms 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.
Like the previous class except that high level encryption is used on
all commnnications. 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.
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.
Like the previous class except that the repository will attempt
wireless commnnication to report tampering and will employ noisy
alarms.
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.

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
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.
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

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Credit Servers

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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.
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 financia! 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.
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.
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

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reporting the transaction to minimize transaction processing
at the risk of losing some transactions.

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.
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.
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."
The Usage Rights Grammar is listed in it's entirety in FIG.
15 and is described below.
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.
Grammar element 1502 "Right:=(Right-Code {CopyCount} {Control-Spec} {Time-Spec} {Access-Spec} {FeeSpec})" 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.
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.
A Grammar element 1503 "Right-Code:=RenderCode ITransport -Code IF ile-Management -Code IDerivativeWorks-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.
Grammar element 1504 "Render-Code:=[Play: {Player:
Player-ID}IPrint: {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.
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.
Print: To render the work in a medium that is not further
protected by usage rights, such as printing on paper.
Grammar
element
1505
"Transport-Code:=
[CopyiTransferiLoan {Remaining-Rights: Next-Set-ofRights}] {(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

Usage Rights Language
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.
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.
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 Control1457. Each of these specifications will
be described in greater detail below with respect to the language grammar elements.
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"[ albic]" 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.
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 oflists containingx.
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

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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.
Copy: Make a new copy of a work
Transfer: Moving a work from one repository to another.
Loan: Temporarily loaning a copy to another repository for
a specified period of time.
Grammar element 1506 "File-Management-Code:=
Backup
{Back-Up-Copy-Rights:
Next-Set-of
{Name:HideRights} IRestore IDelete IF olderl Directory
Locall Hide-Remote} {Parts :Hide-Local IHide-Remote}"
lists a category of rights involving operations for file management, such as the making ofbackup copies to protect the copy
owner against catastrophic equipment failure.
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.
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.
Backup: To make a backup copy of a digital work as protection against media failure.
Restore: To restore a backup copy of a digital work.
Delete: To delete or erase a copy of a digital work.
Folder: To create and name folders, and to move files and
folders between folders.
Directory: To hide a folder or it's contents.
Grammar element 1507 "Derivative-Works-Code:
[Extract IEmbed IEdit {Process: Process-ID}] {Next -CopyRights: Next-Set-ofRights }"lists a category of rights involving the use of a digital work to create new works.
Extract: To remove a portion of a work, for the purposes of
creating a new work.
Embed: To include a work in an existing work.
Edit: To alter a digital work by copying, selecting and
modifYing portions of an existing digital work.
Grammar
element
1508
"Configuration-Code:=
InstalliUninstall" 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.
Install: To install new software on a repository.
Uninstall: To remove existing software from a repository.
Grammar element 1509 "Next-Set-of-Rights:={ (Add: SetOf-Rights)} {(Delete: Set-Of-Rights)} {(Replace: Set-OfRights)} {(Keep: Set-Of-Rights)}" defines how rights are
carried forward for a copy of a digital work. If the Next-CopyRights 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.
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
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.
Grammar element 1510 "Copy-Count:=(Copies: positiveintegeriOiunlimited)" 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
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.
Grammar element 1511 "Control-Spec:=(Control:
{RestrictableiUnrestrictable}
{UnchargeableiChargeable}-)" 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
It is often desirable to assign a start date or specify some
duration as to when a right may be exercised. Grmar ele1512
"Time-Spec:=( {Fixed-Interval ISlidingment
IntervaliMeter-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.
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

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on the times over which the usage right applies. The Expirasame rights and fees as other digital works. A repository is
tion-Date specifies the moment at which the usage right ends.
said to have an authorization if that authorization object is
For example, if the Expiration-Date is "Jan. 1, 1995," then the
contained within the repository.
In some cases, an authorization may be required from a
right ends at the first moment of 1995. If the Expiration-Date
is specified as *forever*, then the rights are interpreted as
source other than the document server and repository. An
authorization object referenced by an Authorization-ID can
continuing without end. If only an expiration date is given,
then the right can be exercised as often as desired until the
contain digital address information to be used to set up a
expiration date.
communications link between a repository and the authoriGrammar element 1513 "Fixed-Interval:=From: Startzation source. These are analogous to phone numbers. For
Time" is used to define a predetermined interval that runs 10 such access tests, the communication would need to be estabfrom the start time to the expiration date.
lished and authorization obtained before the right could be
Grammar element 1514 "Sliding-Interval:=Interval: Useexercised.
Duration" is used to define an indeterminate (or "open") start
For one-time usage rights, a variant on this scheme is to
have a digital ticket. A ticket is presented to a digital ticket
time. It sets limits on a continuous period of time over which
the contents are accessible. The period starts on the first 15 agent, whose type is specified on the ticket. In the simplest
case, a certified generic ticket agent, available on all reposiaccess and ends after the duration has passed or the expiration
tories, is available to "punch" the ticket. In other cases, the
date is reached, whichever comes first. For example, if the
ticket may contain addressing information for locating a
right gives 10 hours of continuous access, the use-duration
"special" ticket agent. Once a ticket has been punched, it
would begin when the first access was made and end 10 hours
later.
20 carmot be used again for the same kind of transaction (unless
Grammar element 1515 "Meter-Time:=Time-Remaining:
it is unpunched or refreshed in the marmer described below.)
Remaining-Use" is used to define a "meter time," that is, a
Punching includes marking the ticket with a timestamp of the
measure of the time that the right is actually exercised. It
date and time it was used. Tickets are digital works and can be
differs from the Sliding-Interval specification in that the time
copied or transferred between repositories according to their
that the digital work is in use need not be continuous. For 25 usage rights.
In the currently preferred embodiment, a "punched" ticket
example, if the rights guarantee three days of access, those
becomes "unpunched" or "refreshed" when it is copied or
days could be spread out over a month. With this specificaextracted. The Copy and Extract operations save the date and
tion, the rights can be exercised until the meter time is
exhausted or the expiration date is reached, whichever comes
time as a property of the digital ticket. When a ticket agent is
30 given a ticket, it can simply check whether the digital copy
first.
Remaining-U se:=Time-Unit
was made after the last time that it was punched. Of course,
Start-Time:=Time-Unit
the digital ticket must have the copy or extract usage rights
Use-Duration:=Time-Unit
attached thereto.
The capability to unpunch a ticket is important in the folAll of the time specifications include time-unit specifications in their ultimate instantiation.
35 lowing cases:
Security Class and Authorization Specification
A digital work is circulated at low cost with a limitation that
The present invention provides for various security mechait can be used only once.
A digital work is circulated with a ticket that can be used
nisms to be introduced into a distribution or use scheme.
once to give discounts on purchases of other works.
Grmar element 1516 "Access-Spec:=( {SC: SecurityClass} {Authorization: Authorization-ID*} {Other-Authori- 40
A digital work is circulated with a ticket (included in the
zation: Authorization-ID*} {Ticket: Ticket-ID} )"provides a
purchase price and possibly embedded in the work) that can
be used for a future upgrade.
means for restricting access and transmission. Access speciIn each of these cases, if a paid copy is made of the digital
fications can specifY a required security class for a repository
to exercise a right or a required authorization test that must be
work (including the ticket) the new owner would expect to get
satisfied.
45 a fresh (unpunched) ticket, whether the copy seller has used
The keyword "SC:" is used to specify a minimum security
the work or not. In contrast, loaning a work or simply translevel for the repositories involved in the access. If"SC:" is not
ferring it to another repository should not revitalize the ticket.
specified, the lowest security level is acceptable.
Usage Fees and Incentives Specification
The optional "Authorization:" keyword is used to specify
The billing for use of a digital work is fundamental to a
required authorizations on the same repository as the work. so commercial distribution system. Grammar Element 1517
The optional "Other-Authorization:" keyword is used to
"Fee-Spec:={ Scheduled-Discount}
Regular-FeespecifY required authorizations on the other repository in the
SpeciScheduled-Fee-SpeciMarkup-Spec" provides a range
transaction.
of options for billing for the use of digital works.
The optional "Ticket:" keyword specifies the identity of a
A key feature of this approach is the development oflowticket required for the transaction. A transaction involving 55 overhead billing for transactions in potentially small
amounts. Thus, it becomes feasible to collect fees of only a
digital tickets must locate an appropriate digital ticket agent
who can "punch" or otherwise validate the ticket before the
few cents each for thousands of transactions.
transaction can proceed. Tickets are described in greater
The grammar differentiates between uses where the charge
detail below.
is per use from those where it is metered by the time unit.
In a transaction involving a repository and a document 60 Transactions can support fees that the user pays for using a
digital work as well as incentives paid by the right grantor to
server, some usage rights may require that the repository have
users to induce them to use or distribute the digital work.
a particular authorization, that the server have some authoriThe optional scheduled discount refers to the rest of the fee
zation, or that both repositories have (possibly different)
authorizations. Authorizations themselves are digital works
specification-discounting it by a percentage over time. If it
(hereinafter referred to as an authorization object) that can be 65 is not specified, then there is no scheduled discount. Regular
moved between repositories in the same marmer as other
fee specifications are constant overtime. Scheduled fee specidigital works. Their copying and transferring is subject to the
fications give a schedule of dates over which the fee specifi-

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cations change. Markup specifications are used in d-blocks
for adding a percentage to the fees already being charged.
Grammar Element 1518 "Scheduled-Discount:=(Scheduled-Discount: (Time-Spec Percentage)*)" A ScheduledDiscount 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.
Grammar Element 1519 "Regular-Fee-Spec:=({Fee:
IIncentive:} [Per-Use-SpeciMetered-Rate-SpeciBest-PriceSpeciCall-For-Price-Spec] {Min: Money-Unit Per: TimeSpec} {Max: Money-Unit Per: Time-Spec} To: AccountID)" provides for several kinds of fee specifications.
Fees are paid by the copy-owner/userto the revenue-owner
if Fee: is specified. Incentives are paid by the revenue-owner
to the user iflncentive: 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.
Grammar element 1520 "Per-Use-Spec:=Per-Use: Moneyunit" defines a simple fee to be paid every time the right is
exercised, regardless ofhow much time the transaction takes.
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.
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.
Grammar element 1523 "Call-For-Price-Spec:=Call-ForPrice" is similar to a "Best-Price-Spec" in that it is intended to
accommodate cases where prices are dynamic. A Call-ForPrice Spec requires a communication with a dealer to determine the price. This option caunot be exercised if the repository caunot 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.
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.

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
((Play) (Transfer (SC: 3)) (Delete)
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.
((Play) (Transfer (SC: 3)) (Delete) (Backup) (Restore (Fee:
Per-Use: $5 To: Account-ID-678)))
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.
((Play) (Transfer (SC: 3))
(Copy (SC:3)(Fee: Per-Use: $5 To: Account-ID-678))
(Delete (Incentive: Per-Use: $2.50 To: Account-ID-678)))
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.
((Play) (Transfer (SC: 3))
Copy (SC: 3) (Fee: Per-Use: $10 To: Account-ID-678))
Delete) (Backup) (Restore (SC: 3) (Fee: Per-Use: $5 To:
Account-ID-678)))
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.
((Play) (Transfer (SC: 3))
(Copy Authorization: License-123-ID (SC: 3)))
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.
((Play) (Print Printer: Printer-567-ID (Fee: Per-Use: $1 To:
Account-ID-678)))
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.
((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))
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 of25 cents in any day that it is used, payable to the
account described by Account-ID-567.
((Play) (Transfer) (Delete)(Loan 2 (Delete: Transfer
Loan)))
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 carmot be transferred. When
both copies are loaned out, no rights can be exercised on the
original on the repository.

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((Play) (Transfer) (Delete) (Backup) (Restore (SC:3))
with repositories that are above the lowest security class are
(Loan 2 Remaining-Copy-Rights: (Delete: Play Transfer)
encrypted utilizing a public key encryption technique. Public
Next-Set-of-Rights: (Delete: Transfer Loan)))
key encryption is a well kuown technique in the encryption
Similar to previous example. Rights to Backup and Restore
arts. The term key refers to a numeric code that is used with
the work are added, where restoration requires a repository of
encryption and decryption algorithms. Keys come in pairs,
at least security level three. When all copies of the work are
where "writing keys" are used to encrypt data and "checking
loaned out, the remaining copy cannot be played or transkeys" are used to decrypt data. Both writing and checking
ferred.
keys may be public or private. Public keys are those that are
((Play) (Transfer) (Copy) (Print) (Backup) (Restore (SC:
distributed to others. Private keys are maintained in confi3))
10 dence.
(Loan 1 Remaining-Copy-Rights: (Add: Play Print
Key management and security is instrun1ental in the sucBackup)
cess of a public key encryption system. In the currently preNext-Set-of-Rights: (Delete: Transfer Loan)
ferred embodiment, one or more master repositories maintain
(Fee: Metered: $10 Per: 1:0:0 To: Account-ID-567))
the keys and create the identification certificates used by the
15
(Loan 1 Remaining-Copy-Rights:
repositories.
Add: ((Play Player: Player-876-ID) 2 (From: Feb. 14, 1994
When a sending repository transmits a message to a receivUntil: Feb. 15, 1995)
ing repository, the sending repository encrypts all of its data
(Fee: Metered: $0.01 Per: 0:1:0 Min: $0.25 Per: 0/1/0
using the public writing key of the receiving repository. The
To: Account-ID-567))))
The original work has rights to Play, Transfer, Copy, Print, 20 sending repository includes its name, the name of the receiving repository, a session identifier such as a nonce (described
Backup, Restore, and Loan. There are two versions of the
below), and a message counter in each message.
Loan right. Thefirstversionofthe loan right costs $10perday
In this way, the communication can only be read (to a high
but allows the original copy owner to exercise free use of the
probability) by the receiving repository, which holds the priPlay, Print and Backup rights. The second version of the Loan
right is free. None of the original rights are applicable. How- 25 vate checking key for decryption. The auxiliary data is used to
guard against various replay attacks to security. If messages
ever a right to Play the work at the specified metered rate is
ever arrive with the wrong counter or an old nonce, the reposiadded.
tories can assume that someone is interfering with commu((Play Player: Player-Small-Screen-123-ID)
nication and the transaction terminated.
(Embed (Fee: Per-Use $0.01 To: Account-678-ID))
30
The respective public keys for the repositories to be used
(Copy (Fee: Per-Use $1.00 To: Account-678-ID)))
for encryption are obtained in the registration transaction
The digital work can be played on any player with the
described below.
identifier Player-Small-Screen-123-ID. It can be embedded
Session Initiation Transactions
in a larger work. The embedding requires a modest one cent
A usage transaction is carried out in a session between
registration fee to Account-678-ID. Digital copies can be
35 repositories. For usage transactions involving more than one
made for $1.00.
repository, or for financial transactions between a repository
Repository Transactions
and a credit server, a registration transaction is performed. A
second transaction termed a login transaction, may also be
When a user requests access to a digital work, the reposineeded to initiate the session. The goal of the registration
tory will initiate various transactions. The combination of 40 transaction is to establish a secure charmel between two
transactions invoked will depend on the specifications
repositories who kuow each others identities. As it is assumed
assigned for a usage right. There are three basic types of
that the communication channel between the repositories is
transactions, Session Initiation Transactions, Financial
reliable but not secure, there is a risk that a non-repository
Transactions and Usage Transactions. Generally, session inimay mimic the protocol in order to gain illegitimate access to
tiation transactions are initiated first to establish a valid ses- 45 a repository.
sian. When a valid session is established, transactions correThe registration transaction between two repositories is
described with respect to FIGS. 16 and 17. The steps
sponding to the various usage rights are invoked. Finally,
described are from the perspective of a "repository-!" regisrequest specific transactions are performed.
tering its identity with a "repository-2". The registration must
Transactions occur between two repositories (one acting as
a server), between a repository and a document playback 50 be symmetrical so the same set of steps will be repeated for
repository-2 registering its identity with repository-!. Referplatform (e.g. for executing or viewing), between a repository
and a credit server or between a repository and an authorizaring to FIG. 16, repository-! first generates an encrypted
tion server. When transactions occur between more than one
registration identifier, step 1601 and then generates a regisrepository, it is assumed that there is a reliable communicatration message, step 1602. A registration message is comtion channel between the repositories. For example, this could 55 prised of an identifier of a master repository, the identification
be a TCP/IP channel or any other commercially available
certificate for the repository-! and an encrypted random regchannel that has built-in capabilities for detecting and coristration identifier. The identification certificate is encrypted
by the master repository in its private key and attests to the
recting transmission errors. However, it is not assumed that
fact that the repository (here repository-!) is a bona fide
the communication channel is secure. Provisions for security
and privacy are part of the requirements for specifYing and 60 repository. The identification certificate also contains a public
implementing repositories and thus form the need for various
key for the repository, the repository security level and a
transactions.
timestamp (indicating a time after which the certificate is no
Message Transmission
longer valid.) The registration identifier is a number generTransactions require that there be some communication
ated by the repository for this registration. The registration
between repositories. Communication between repositories 65 identifier is unique to the session and is encrypted in repository-l's private key. The registration identifier is used to
occurs in units termed as messages. Because the communiimprove security of authentication by detecting certain kinds
cation line is assumed to be unsecure, all communications

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of communications based attacks. Repository-! then transmits the registration message to repository-2, step 1603.
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.
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 "hatlist", 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 ofhotlist 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 ofhotlist certificates, ultimately
exchanging only those lists that they had not previously
received. The "hotlists" are maintained and distributed by
Master repositories.
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.
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-!. 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-! and repository2. 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-!. 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-!
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!. The performance message is transmitted to repository-!,
step 1610, where it is decrypted by repository-! using its
private key, step 1611. Repository-! 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-! 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.
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-!.) Referring to FIG. 17,
repository-! creates a session key pair, step 1701. A first key
is kept private and is used by repository-! 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 repository2, 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.
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-!, step 1706. Upon
receipt, repository-! 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-!, step 1710. The current time
is compared to the time received from repository-!, 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-!
and repository-2.
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.
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
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:

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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.
Registration and LOGIN transactions, by which a credit
server establishes its bona fides to a billing clearinghouse.
AnAssign-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.
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.
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.)
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.
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
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.
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.
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.
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.
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.
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.
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
carmot be completed and the transaction terminates per step
1805.
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.
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

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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.
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.
It should be noted that the order in which the conditions are
checked need not follow the order of steps 1806-1815.
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.
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, ifthere are
fee specifications associated with the right, the server initiates
End-Charge financial transaction to confirm billing, step
1819.
Transmission Protocol
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 charmel 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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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.
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.
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.

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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.
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.
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.
The transactions for specific usage rights are now discussed.
The Copy Transaction
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.
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.
The repositories perform the common opening transaction
steps.
The server transmits the requested contents and data to the
client according to the transmission protocol. If a Next-SetOf-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.
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.
The repositories perform the common closing transaction
steps.
The Transfer Transaction
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.
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.

The repositories perform the common opening transaction
steps.
The server transmits the requested contents and data to the
requester according to the transmission protocol. If a NextSet-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.
The requester records the work contents, data, and usage
rights and stores the work.
The server decrements its copy count by the number of
copies involved in the transaction.
The repositories perform the common closing transaction
steps.
If the number of copies remaining in the server is now zero,
it erases the digital work from its memory.
The Loan Transaction
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.
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.
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 caunot extend beyond the period of the original
loan to the server.
The repositories perform the common opening transaction
steps.
The server transmits the requested contents and data to the
requester.
If aNext -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.
The requester records the digital work contents, data, usage
rights, and loan period and stores the work.
The server updates the usage rights information in the
digital work to reflect the number of copies loaned out.
The repositories perform the common closing transaction
steps.
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 caunot use the digital work, unless there
are copies remaining. What happens next depends on the
order of events in time.
Case 1. If the time of the loan period is not yet exhausted
and the requester sends the repository a Return message.
The return message includes the requester identification,
and the transaction ID.
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.
The requester deactivates its copies and removes the contents from its memory.
Case 2. If the time of the loan period is exhausted and the
requester has not yet sent a Return message.
The server decrements the copies-in-use field by the number digital works that were borrowed.

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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
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.
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.
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.
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.
The repositories perform the common opening transaction
steps.
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.
When the player is finished, the player and the requester
remove the contents from their memory.
The repositories perform the common closing transaction
steps.
The Print Transaction
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.
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.
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.

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.
The repositories perform the common opening transaction
steps.
The server transmits blocks of data according to the transmission protocol.
The requester prints the work contents, using the printer.
When the printer is finished, the printer and the requester
remove the contents from their memory.
The repositories perform the common closing transaction
steps.
The Backup Transaction
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.
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.
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.
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.
The repositories perform the common opening transaction
steps.
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.
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.
The repositories perform the common closing transaction
steps.
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
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 cata-

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strophic media failure. Like all usage rights, restoration rights
can include fees and access tests including authorization
checks.
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.
The server verifies that the contents file is available (i.e. a
digital work corresponding to the request has been backedup.) If it is not, it ends the transaction with an error.
The repositories perform the common opening transaction
steps.
The server retrieves the key from the restoration file. It
decrypts the work contents, data, and usage rights.
The server transmits the requested contents and data to the
requester according to the transmission protocol. If a NextSet-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.
The requester stores the digital work.
The repositories perform the common closing transaction
steps.
The Delete Transaction
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.
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.
The repositories perform the common opening transaction
steps.
The server deletes the file, erasing it from the file system.
The repositories perform the common closing transaction
steps.
The Directory Transaction

The repositories perform the common opening transaction
steps.
The server sends the requested data to the requester according to the transmission protocol.
The requester records the data.
The repositories perform the common closing transaction
steps.
The Folder Transaction
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.
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.
The repositories perform the common opening transaction
steps.
The server performs the requested operation--creating a
folder, renaming a folder, or moving a work between folders.
The repositories perform the common closing transaction
steps.
The Extract Transaction
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.
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.
The repositories perform the common opening transaction
steps.
The server transmits the requested contents and data to the
requester according to the transmission protocol. If a NextSet-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.
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.
The repositories perform the common closing transaction
steps.
The Embed Transaction
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 offees by a distributor of the work.
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.
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.

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.
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.
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.
The server verifies that the information is accessible to the
requester.
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.

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The repositories perform the common opening transaction
steps.
The server transmits the requested contents and data to the
requester according to the transmission protocol. If a NextSet-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.
The requester records the contents, data, and usage rights
and embeds the work in the destination file.
The repositories perform the common closing transaction
steps.
The Edit Transaction
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.
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.
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.
The repositories perform the common opening transaction
steps.
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.)
The repositories perform the common closing transaction
steps.
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.
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 col-

orized. A musician may want to allow extraction of portions
of his work but not changing of the tonality.
Authorization Transactions
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.
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.
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.
If a remote authorization server is required, then the authorization process first performs the following steps:
The generic authorization server attempts to set up the
communications channel. (If the charmel cannot be set up,
then authorization fails with an error.)
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.)
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 carmot be found or has
some other error, then the authorization fails with an error.)
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.
If all of the required steps are completed satisfactorily, the
authorization server completes the transaction normally, signaling that authorization is granted.
The Install Transaction
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.
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).
The repositories perform the common opening transaction
steps.
The requester extracts a copy of the digital certificate for
the software. If the certificate cannot be found or the master

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repository for the certificate is not known to the requester, the
transaction ends with an error.
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.)
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 tamperchecking 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.)
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.)
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 ruunable
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.
The repositories perform the common closing transaction
steps.
The Uninstall Transaction
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.
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).
The repositories perform the common opening transaction
steps.
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.
The requester checks whether the software is installed. If
the software is not installed, the transaction ends with an
error.
The requester decrypts the digital certificate using the publie 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.)
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 tamperchecking 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.)
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.
The repositories perform the common closing transaction
steps.

works are illustrated below. These scenarios are meant to be
exemplary rather than exhaustive.
Consumers as Unpaid Distributors
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.
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.
This scenario is performed as follows:
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
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.
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.
This scenario is performed as follows:
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.
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.
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
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 tum, 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.
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.

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This scenario is performed as follows:
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.
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.
A distributor obtains the distribution license and a number
of copies of the work. He makes copies for his customers,
using his distribution license.
A customer buys and uses the work. He carmot make new
copies because he lacks a distribution license.
Super Distributors
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.
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 charmel without diminishing their revenues. This is because distributors collect fees
from copies of any copies that they originally sold. Only
distributors can add fees.
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 carmot 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.
!-Level Distribution Fees
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.
This scenario pays a distributor only for use of copies that
he actually sold.
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
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.
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.
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
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.
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.
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. Altematively, 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
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.
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.
The mechanisms for derived works are the same as those
for distribution.
Limited Reuse
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.
This scenario deals with fine grained control of the rights
and fees for reuse.
This scenario is performed as follows:
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
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.
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
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

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a fee. This scenario deals with fees for loaning rather than fees
for making copies. The fees are collected by the same automatic mechanisms.
This scenario is performed as follows:
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
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 trans action.
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.
This scenario is performed as follows:
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.
The distributor sells the old bundled work and ticket to
customers.
The customer extracts the work and the ticket. He uses the
work according to the agreements until the new version
becomes available.
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.
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.
The consumer can now use the new version of the work.
Distributed Upgrading of Digital Works
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.
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.
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
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.
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.
This scenario is performed as follows:
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
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.
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.
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
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.
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.

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Fees for Font Usage
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.
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
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 offioaded 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.
This scenario is performed as follows:
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
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.
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.
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.

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Glossary
Authorization Repository:
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:
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:
The protocol used by which a repository reports billing
information to a credit server.
Clearinghouse Transactions:
The protocol used between a credit server and a clearinghouse.
Composite Digital Work:
A digital work comprised of distinguishable parts. Each of
the distinguishable parts is itself a digital work which has
usage rights attached.

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Content:
The digital information (i.e. raw bits) representing a digital
work.
Copy Owner:
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:
A term which refers to a party who produces a digital work.
Credit Server:
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:
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):
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:
A term which refers to a party who legitimately obtains a
copy of a digital work and offers it for sale.
Identification (Digital) Certificate:
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:
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:
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:
The protocol used between repositories to establish a
trusted session.
Rendering Repository:
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:
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:
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:
A mode of a repository where it is requesting access to a
digital work.
Revenue Owners:
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:
A mode of a repository where it is processing an incoming
request to access a digital work.
Shell Description Block:
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:
A fee charged to a requester for access to a digital work.
Usage fees are specified within the usage rights language.
Usage Rights:
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:
A set of protocols by which repositories communicate in
the exercise of a usage rights. Each usage right has it's own
transaction steps.
What is claimed:
1. A computer-implemented method of distributing digital
content to at least one recipient computing device to be rendered by the at least one recipient computing device in accordance with usage rights information, the method comprising:
determining, by at least one sending computing device, if
the at least one recipient computing device is trusted to
receive the digital content from the at least one sending
computing device;
sending the digital content, by the at least one sending
computing device, to the at least one recipient computing device only if the at least one recipient computing
device has been determined to be trusted to receive the
digital content from the at least one sending computing
device; and
sending usage rights information indicating how the digital
content may be rendered by the at least one recipient
computing device, the usage rights information being
enforceable by the at least on recipient computing
device.
2. The method of claim 1, wherein the usage rights information further includes a condition under which the content
can be rendered.
3. The method of claim 1, wherein the determination of
trust comprises:
receiving a request from at least one recipient computing
device for an authorization object required to render the
digital content; and
transmitting the authorization object to the at least one
recipient computing device when it is determined that
the request should be granted.
4. The method of claim 1, wherein the determination of
trust comprises:
receiving a registration message from the at least one
recipient device, the registration message including an
identification certificate of the recipient computing
device and a random registration identifier, the identification certificate being certified by a master device;

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validating the authenticity of the at least one recipient
conducting a secure transaction using the session key,
device;
wherein the secure transaction includes sending the digiexchanging messages including at least one session key
tal content to the at least one recipient device.
with the at least one recipient device, the session key to
10. The apparatus of claim 9, wherein the validating comprises:
be used in communications; and
conducting a secure transaction using the session key,
verifYing the identification certificate of the at least one
wherein the secure transaction includes sending the digirecipient device;
tal content to the at least one recipient device.
generating a message to test the authenticity of the at least
one recipient device, the generated message including a
5. The method of claim 1, wherein the validating com10
nonce;
prises:
sending the generated message to the at least one recipient
verifying the identification certificate of the at least one
device; and
recipient device;
generating a message to test the authenticity of the at least
verifYing if the at least one recipient device correctly proone recipient device, the generated message including a 15
cessed the generated message.
nonce;
11. At least one non-transitory computer-readable medium
sending the generated message to the at least one recipient
storing computer-readable instructions that, when executed
device; and
by at least one sending computing device, cause the at least
verifying if the at least one recipient device correctly proone sending computing device to:
determine if the at least one recipient computing device is
cessed the generated message.
20
trusted to receive the digital content from the at least one
6. A sending apparatus for distributing digital content to at
sending computing device;
least one recipient computing device to be rendered by the at
send the digital content, by the at least one sending comleast one recipient computing device in accordance with
usage rights information, the sending apparatus comprising:
puting device, to the at least one recipient computing
25
one or more processors; and
device only if the at least one recipient computing device
one or more memories operatively coupled to at least one
has been determined to be trusted to receive the digital
content from the at least one sending computing device;
of the one or more processors and having instructions
and
stored thereon that, when executed by at least one of the
send usage rights information indicating how the digital
one or more processors, cause at least one of the one or
30
content may be rendered by the at least one recipient
more processors to:
determine if the at least one recipient computing device
computing device, the usage rights information being
enforceable by the at least on recipient computing
is trusted to receive the digital content from the sending apparatus;
device.
send the digital content, by the sending apparatus, to the 35
12. The at least one non-transitory computer-readable
medium of claim 11, wherein the usage rights information
at least one recipient computing device only if the at
least one recipient computing device has been deterfurther includes a condition under which the content can be
mined to be trusted to receive the digital content from
rendered.
the sending apparatus; and
13. The at least one non-transitory computer-readable
send usage rights information indicating how the digital 40 medium of claim 11, wherein the determination of trust comcontent may be rendered by the at least one recipient
prises:
computing device, the usage rights information being
receiving a request from at least one recipient computing
enforceable by the at least on recipient computing
device for an authorization object required to render the
device.
digital content; and
7. The apparatus of claim 6, wherein the usage rights infor- 45
transmitting the authorization object to the at least one
mation further includes a condition under which the content
recipient computing device when it is determined that
can be rendered.
the request should be granted.
8. The apparatus of claim 6, wherein the determination of
14. The at least one non-transitory computer-readable
trust comprises:
medium of claim 11, wherein the determination of trust comreceiving a request from at least one recipient computing 50 prises:
receiving a registration message from the at least one
device for an authorization object required to render the
recipient device, the registration message including an
digital content; and
transmitting the authorization object to the at least one
identification certificate of the recipient computing
recipient computing device when it is determined that
device and a random registration identifier, the identifithe request should be granted.
cation certificate being certified by a master device;
55
9. The apparatus of claim 6, wherein the determination of
validating the authenticity of the at least one recipient
trust comprises:
device;
receiving a registration message from the at least one
exchanging messages including at least one session key
recipient device, the registration message including an
with the at least one recipient device, the session key to
identification certificate of the recipient computing 60
be used in communications; and
device and a random registration identifier, the identificonducting a secure transaction using the session key,
cation certificate being certified by a master device;
wherein the secure transaction includes sending the digivalidating the authenticity of the at least one recipient
tal content to the at least one recipient device.
device;
15. The at least one non-transitory computer-readable
exchanging messages including at least one session key 65 medium of claim 14, wherein the validating comprises:
verifYing the identification certificate of the at least one
with the at least one recipient device, the session key to
be used in communications; and
recipient device;

US 8,393,007 B2
53
generating a message to test the authenticity of the at least
one recipient device, the generated message including a
nonce;
sending the generated message to the at least one recipient
device; and

54
verifYing if the at least one recipient device correctly processed the generated message.

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