U.S. patent application number 09/985096 was filed with the patent office on 2002-03-07 for method of encrypting information for remote access while maintaining access control.
Invention is credited to Cristy, John J., Pensak, David A., Singles, Steven J..
Application Number | 20020029340 09/985096 |
Document ID | / |
Family ID | 23252254 |
Filed Date | 2002-03-07 |
United States Patent
Application |
20020029340 |
Kind Code |
A1 |
Pensak, David A. ; et
al. |
March 7, 2002 |
Method of encrypting information for remote access while
maintaining access control
Abstract
The invention provides for encrypting electronic information
such as a document so that only users with permission may access
the document in decrypted form. The process of encrypting the
information includes selecting a set of policies as to who may
access the information and under what conditions. A remote server
stores a unique identifier for the information and associates an
encryption/decryption key pair and access policies with the
information. Software components residing on the author's computer
retrieve the encryption key from the remote server, encrypt the
information, and store the encrypted information at a location
chosen by the author. A user wishing to access the information
acquires the encrypted information electronically. Software
components residing on the viewing user's computer retrieve the
associated decryption key and policies, decrypt the information to
the extent authorized by the policies, and immediately delete the
decryption key from the viewing user's computer upon decrypting the
information and rendering the clear text to the viewing user's
computer screen. The software components are also capable of
prohibiting functional operations by the viewing user's computer
while the clear text is being viewed.
Inventors: |
Pensak, David A.; (West
Chester, PA) ; Cristy, John J.; (Landenberg, PA)
; Singles, Steven J.; (Newark, DE) |
Correspondence
Address: |
Attn: Stuart T.F. Huang
STEPTOE & JOHNSON LLP
1300 Connecticut Ave., NW
Washington
DC
20036
US
|
Family ID: |
23252254 |
Appl. No.: |
09/985096 |
Filed: |
November 1, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09985096 |
Nov 1, 2001 |
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09906811 |
Jul 18, 2001 |
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09906811 |
Jul 18, 2001 |
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09321839 |
May 28, 1999 |
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6289450 |
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Current U.S.
Class: |
713/182 ;
705/51 |
Current CPC
Class: |
H04L 63/0442 20130101;
H04L 63/0428 20130101; H04L 2463/101 20130101; H04L 63/062
20130101; H04L 63/10 20130101; H04L 63/166 20130101 |
Class at
Publication: |
713/182 ;
705/51 |
International
Class: |
H04L 009/00 |
Claims
What is claimed is:
1. A method of controlling distribution of electronic information
comprising the steps of: retrieving, at a user location, a segment
of encrypted electronic information; receiving, from a key server,
(a) a copy of a decryption key for the segment, and (b) at least
one user limitation assigned to the segment and associated with the
decryption key; accessing the segment using the copy of the
decryption key at the user location for the segment and a control
process, the control process responsive to a user limitation to
control distribution of the electronic information; and destroying
the copy of the decryption key at the user location after accessing
the segment.
2. The method of controlling distribution of electronic information
of claim 1, wherein access to the decryption key is controlled by
the key server subject to a unique segment identification
associated with the segment and the user limitation associated with
the segment.
3. A method of accessing first and second encrypted segments of an
electronic document comprising the steps of: retrieving, at the
user location, a first encrypted segment of the electronic
document; receiving, from a key server, (a) a copy of a first
decryption key for the first segment and (b) at least one user
limitation assigned to the first segment and associated with the
first decryption key; accessing the first segment using the copy of
the first decryption key for the first segment; and at the user
location, destroying the copy of the first decryption key for the
first segment as a precondition to receiving a decryption key for
accessing a second segment of the electronic document.
Description
BACKGROUND
[0001] This invention relates to an electronic security system for
electronic objects such as documents, video and audio clips and
other objects that can be transmitted via a network.
[0002] Electronic security systems have been proposed for managing
access to electronic information and electronic documents so that
only authorized users may open protected information and documents.
Several software tools have been developed to work with particular
document readers such as Adobe Acrobat Exchange and Adobe Acrobat
Reader.
[0003] A need still exists for improved systems for providing
access to encrypted information by authorized users and which
prevent unauthorized users from gaining access to the encrypted
information. The present invention allows the authoring user or
other controlling party to maintain access control over the
electronic information.
SUMMARY
[0004] The preferred embodiment(s) of the invention are summarized
here to highlight and introduce some aspects of the present
invention. Simplifications and omissions may be made in this
summary. Such simplifications and omissions are not intended to
limit the scope of the invention.
[0005] The object of the present invention is to provide a system
and method for encrypting electronic information so that access to
the information can be controlled by the author or other
controlling party.
[0006] A further object of the present invention is to provide an
electronic encryption/decryption system and method in which a
central server maintains control over the electronic encryption and
decryption keys.
[0007] A further object of the present invention is to provide an
electronic encryption/decryption system and method in which
electronic encryption and decryption keys are not retained by an
encrypting or decrypting party.
[0008] A further object of the present invention is to provide a
system and method for encrypting electronic information so that
access to the information can be dynamically changed from a single
location without the necessity of collecting or redistributing the
encrypted information.
[0009] A further object of the present invention is to provide an
electronic encryption/decryption system and method in which access
to electronic information can be permanently revoked by destroying
the association of a decryption key to the electronic
information.
[0010] These and other objects will become apparent from the
figures and written description contained herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Preferred embodiment(s) of the invention will be discussed
below with reference to attached drawings in which:
[0012] FIG. 1 is a block diagram illustrating a system
configuration of an authoring tool, a viewing tool, and a remote
server of the electronic encryption system.
[0013] FIG. 2 is a block diagram illustrating a detailed system
configuration and functions associated with each component of the
electronic encryption system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0014] Referring now to the Figures wherein like reference numerals
indicate like elements, in FIG. 1, the system of the preferred
embodiment can be broken down conceptually into three functional
components: an authoring tool 102, a viewing tool 104, and a remote
server 106. For convenience, the embodiments described herein are
described with respect to a document in Adobe Acrobat Exchange, but
other embodiments using other base software packages are possible.
Other types of electronic information, as determined by the base
software package chosen, can be encrypted using the present
invention.
[0015] The authoring tool 102 allows an authoring user 108 to
convert a text document 110 to unreadable form 112 using a strong
encryption algorithm and an encryption key, or set of encryption
keys, provided by the remote server 106. The authoring tool 102
also registers the electronic document or information with the
remote server 106 and associates a set of access policies with the
encryption key so that only selected viewing users 116 under
selected circumstances may view the document in clear text. The
document or information may also be broken down into segments using
the authoring tool 102, so that certain segments within a document
may have different access policies. For example, a set of users may
be allowed to view pages 1-5 of a 10 page document in clear text,
while a subset of those users may be allowed to view all 10 pages
of the document. The authoring tool 102 also allows the authoring
user 108 to block certain functions normally accessible by the
viewing user 116. For example, the authoring user 108 may deny a
viewing user 116 privileges such as printing and copying of the
clear text.
[0016] The viewing tool 104 allows a viewing user 116 to decrypt
the document 112 an authoring user 108 has encrypted, provided the
authoring user 108 has associated an access policy with the
decryption key which grants access to the clear text to the viewing
user 116. The viewing tool 104 retrieves the decryption key 118
associated with the document segment 112 from the remote server
106, decrypts the document into clear text, renders the document
segment, and destroys the decryption key and the clear text version
of the document segment. The viewing tool 104 prevents the saving
of the decryption key or the clear text version of the document.
The viewing tool 104 also blocks the viewing user's machine from
performing certain functions, such as printing or copying, as
directed by the authoring user 108 during registration of the
document 110.
[0017] The secure remote server 106 performs several functions. The
remote server 106 generates encryption keys 114 for each document
segment, maintains decryption keys 118 for registered encrypted
documents 112, authenticates requests for viewing a document
segment, grants access to registered documents 112 by providing
decryption keys 118 and associated access policies to authorized
viewing users 116, and maintains an encrypted secure central
database which provides association between registered authoring
users, registered documents, associated decryption keys, associated
policies for each document, options for each user and document, and
associated registered viewing users. The remote server 106 does not
store or receive the actual document, either encrypted or
unencrypted.
[0018] The authoring tool 102 and the viewing tool 104 each use
essentially the same suite of software tools. As shown in FIG. 2,
the software tools reside on the authoring and viewing users'
computers 222, 224. Registration with the central remote server 206
determines which functions within the suite of software tools are
available to a particular user. The software tools include a
Configuration Utility 226, an Administrator Utility 228, and an
Application Interface 230. In the embodiment using Adobe Acrobat
Exchange, the Application Interface is a "Plug-In," which uses SDK
and Plug-In Standard Interface. The three software tools run in
conjunction with base viewing or playback software 232, such as
Adobe Acrobat Exchange, a web browser, a word processor, an audio
or video playing application, a custom data processing, or a
specialized low-level device driver, such as a hard disk driver,
video driver, or audio driver. The base software package 232 will
depend on the type of data stream to be encrypted/decrypted.
THE SECURE REMOTE SERVER
[0019] The secure remote server 206 is a server which is remote
from an authoring or viewing user 208, 216. The server 206
maintains a database 236 of encryption keys and associated
decryption keys for distribution to registered or authorized users.
The remote server 206 also maintains a database which associates
registered document segments, which are identified by unique
segment IDs, with authoring users, user access profiles, document
access policies and options, and associated encryption/decryption
keys. The remote server 206 does not actually store registered
documents or segments, but instead relates identifying information
about a document to the associated information.
[0020] The remote server 206 also tracks and maintains records of
requests to view documents and to obtain document decryption keys
238. The records may be used to monitor the system for suspicious
activity. For example, a single user requesting the decryption key
for a document several times during a specific time period might be
an indication of suspicious activity. The server can then provide
an alert message to a pager, e-mail or fax, thus allowing timely
investigation of the activity. The request information may also be
used for the purposes of non-repudiation or as a basis for billing
in situations where access to the system or access to protected
information is being sold.
[0021] All communication between the remote server 206 and a user's
computer 222, 224 is encrypted using Secure Socket Layer (SSL)
protocols. Once an SSL tunnel has been negotiated between a user's
machine 222, 224 and the secure server 206, a session key is
negotiated. Thus, communications to and from the secure server 206
and a user's computer 222, 224 are doubly encrypted.
[0022] Registration with the remote server 206 of a user or
automated system wishing to use the system is done separately from
any communication for registering a document or viewing a document.
A user wishing to register documents for viewing by other users, or
viewing registered document registered by other users, must contact
the server independently, possibly through a separate human
Coordinator 240 or separate network link which can collect payment
for the authoring, viewing, and other services, can verify the
identity of the user and provide the server with user
identification information and user authorization profiles.
[0023] The server may be a single server, a set of synchronized
servers, or dual servers with a shared database.
THE CONFIGURATION UTILITY
[0024] The Configuration Utility 226 defines a local user
(authoring or viewing) on the user's computer 222, 224. The
Configuration Utility 226 establishes the communication parameters
for a local user and the remote server 206. For example, the
Configuration Utility 226 will query the user to define a local
user profile, to include name, password and other identifying
information. This local user profile must match the information
provided by a user to the Coordinator 240 at the remote server
206.
[0025] The Configuration Utility 226 is also responsible for
maintaining information regarding the authentication and secure
communication method used by the local user, for example,
certificate, secret passphrase, smart card, etc. The Configuration
Utility 226 maintains information about the local user's secure
communication method, for example, the certificate and
certification authority for a certificate based secure
communication system.
THE ADMINISTRATOR UTILITY
[0026] The Administrator Utility 226 is a network client
application used by the human Coordinator 240 and other users to
control access to documents selected for encryption by defining
policies associated with a document. The Administrator Utility 228
is a software program residing on the user's computer 222, 224. The
Coordinator 240 or authoring user 208 uses the Administrator
Utility 228 to define policies related to a particular user. For
example, the Coordinator 240 can use the Administrator Utility 228
to control the functions available to a particular authoring user
208, which might depend on the fees paid by the authoring user 208,
or the Coordinator 240 can control the amount of access an
authoring user 208 can allow to viewing users 216. Other policies
that an individual can define using the Administrator Utility 228
are site policies, group policies, and default policies.
[0027] The Administrator Utility 228 allows the Coordinator 240 or
authoring or viewing user 208, 216 to determine what documents have
been registered by a particular user by accessing the registered
user database 236. The Administrator Utility 228 also allows an
authoring user to permanently disable the viewing of documents by
deleting the associated decryption key from the server. The
Administrator Utility 228 also allows an authoring user 208 to
initially define the policies related to his documents and to
change the policies after the documents have initially been
registered.
[0028] The Administrator Utility 228 allows a normal authoring user
208 to create, edit, and delete time windows, network
specifications and policy templates; view the list of registered
documents; and view and edit the policies of documents that are
registered. The Administrator Utility 228 allows the Coordinator
240 to create, edit, and delete users and user policies; create,
edit, and delete groups of users and group polices; create, edit,
and delete document groups and document group policies; define and
modify the Site and Default polices; create, edit, and delete
document override policies; and view the activity log and set up
notification policies
THE APPLICATION INTERFACE
[0029] The Application Interface 230 of the prefered embodiment is
a standard "Plug-In" to Adobe Acrobat Exchange using SDK and
Plug-In Standard Interface. The Plug-In 230 provides a user screen
interface to allow the user to access the particular functions
associated with registering and viewing documents and communicating
with the server. The Plug-In Screen may be integral to the Adobe
User Interface Window or may be a separate window. In the preferred
embodiment, the Plug-In 230 modifies the Adobe User Interface
Window by adding functional "buttons" such as register, create
policies, tag, encrypt, view and decrypt.
[0030] The Plug-In 230 allows encryption and decryption of PDF
files using encryption keys from the remote server 206. The Plug-In
230 connects to the server 206, authenticates the user to the
server, registers documents with the server, selects policies at
the server as they have been defined by the authoring user 208
using the Administrator Utility 228.
[0031] In addition, the Plug-In 230 blocks certain functions at the
viewing user's computer 224 that are otherwise available in Adobe
Acrobat Exchange. For example, if the authoring user 208 has
limited access to a document so that a viewing user 216 is
prohibited from printing a viewed document, the Plug-In 230
temporarily disables the print function of Adobe Acrobat Exchange.
Among the functions that the Plug-In 230 can disable are print,
copy, cut, paste, save, and other functions. Other functions may be
disabled or limited as appropriate for the type of file viewed and
the access level. The Application Interface 230 is designed in such
a way that it does not disclose either the decryption key or the
clear text or unencrypted representation of the protected
information content in electronic form.
THE GRAPHICAL USER INTERFACE
[0032] The Graphical User Interface ("GUI")supports standard user
interface objects such as push buttons, text input fields, lists,
menus, and message boxes. The GUI is controlled by the mouse and
keypad. The GUI has multiple windows that allow real time setup of
server configuration such as who may register a document, who may
view a document, when a document may be viewed and on which host
the document key and viewing information resides.
INITIAL USER SETUP
[0033] A user who wishes to register or to access information must
first register and be recognized by the server 206, as represented
by reference numeral 1042, 1044 in FIG. 2. The user 208, 216
contacts the server 206 independently, possibly through a separate
human Coordinator 240 or separate network link which can collect
payment for the authoring, viewing and other services; verify the
identity of the user; and provide the server with user
identification information and user authorization profiles. Once
the user 208, 216 is registered with the server 206, the suite of
software tools is provided to the user.
[0034] The user must have installed the base software 230, such as
Adobe Acrobat Exchange, on his computer. The user then installs the
Application Interface 230 provided by the Coordinator 240, as well
as the Administrator and Configuration Utilities 228, 226. In one
embodiment, upon running the Application Interface 230, the
Application Interface 230 will install the Administrator and
Configuration Utilities 228, 226 on the user's machine. There is no
network activity involved in the installation of the Application
Interface 230, Administrator, or Configuration Utilities 228,
226.
CREATING POLICIES USING THE ADMINISTRATOR
[0035] Once a user 208, 216 is registered and the Configuration
Utility 226 has set up identification and encryption information
for the user 208, 216, the user authorized to do so can use the
Administrator Utility 228 to create policies associated with a
specific document. An authoring user 208 wishing to register a
document creates policies to define who, when and how a document
may be viewed or otherwise accessed.
[0036] The authoring user 208 runs the Administrator Utility 228
which has been installed on his machine 222 and instructs the
Administrator Utility 228 to create policies for a document. The
Administrator Utility 228 will request the information provided
during set up to the Configuration Utility 226 such as username,
passphrase, and method of authentication to verify the user's
identity. The Administrator Utility 228 will also ask on which
server the authoring user 208 wishes to register his document. The
Administrator Utility 228 will then establish a connection to the
remote server through the Application Interface 230.
[0037] The remote server 206 and the authoring or viewing user's
computer 222, 224 communicating with the server 206 will negotiate
a standard Secure Socket Layer (SSL) encryption tunnel, as
represented in FIG. 2 by reference numerals 1046, 1056.
[0038] Once the SSL tunnel is established, the user's computer 222,
224 and the server 206 negotiate a secondary session key, as
represented in FIG. 2 by reference numerals 1048, 1058. All
subsequent communications is additionally encrypted using 128-bit
RC4 and this secondary session key. All communication between the
users'computers 222, 224 and the server 206 is thus doubly
encrypted.
[0039] Once the doubly encrypted communication link is established
between the authoring user's computer 222 and the server 206, the
authoring user's computer 222 provides login and authentication
information to the server 206, 1050. The server 206 authenticates
the authoring user's 208 identity and verifies that the authoring
user 208 has authority to use the system by checking a database of
registered users 236 maintained on the server. The information
provided by the authoring user 208 to the Configuration Utility 226
is compared to the information provided by the user to the
Coordinator 240 during the independent user registration process
1042, 1044. The database 234 contains all of the access controls
related to a particular user, so that if a user is only authorized
to view documents, he will not be allowed to use the system to
register or encrypt documents.
[0040] After the server 206 authenticates the authoring user 208
and verifies that the authoring user 208 is authorized to register
documents, the Administrator Utility 228 allows the authoring user
208 to create policies applicable to a particular viewing user 216,
a group of viewing users, or a default policy for all other users.
The policies are then communicated to the server 206, 1051.
Policies define who may view a document, when, and under what
conditions. Policies are created by combining a set of constraints
including allowable or denied users and groups, time ranges, and
Internet Protocol (IP) addresses. Access to a document by a viewing
user 216 is determined by combining the user policy, document
policy, as well as possibly the group policy and document group
policy. If the Coordinator 240 has created a document override
policy for a document, then the override takes precedence over the
regular document policy defined by the authoring user. Policies
include limiting who may view a document or portion of a document
and the time frame during which a user may view the document.
[0041] The Administrator Utility 228 also allows the authoring user
208 to create options. Options specify what functions of the base
software 232 are temporarily disabled so that the viewing user 216
is prohibited from accessing them while viewing the document. An
option can also enforce a watermark on printing. For example, the
authoring user 208 can prohibit a particular viewing user 216 from
printing, saving, or copying a particular document or portion of a
document. These Options are defined by the authoring user 208 using
the Administrator Utility 228, but the options are enforced by the
Application Interface 230.
ENCRYPTING DOCUMENTS AND DATA STREAMS
[0042] An authoring user 208 wishing to encrypt a document will
open the document on his computer 222. The Application Interface
230 must also be loaded before the document or information can be
encrypted. In the preferred embodiment, the Plug-In 230 adds menu
items to the menu bar in Adobe Acrobat Exchange such as "tag" and
"encrypt." "Tag" allows the authoring user 208 to select segments
of the document to be encrypted. The authoring user 208 can assign
different policies to different tagged segments of a single
document, i.e., policies are associated with segments. A segment
may consist of any subset of the entire document or the entire
document. Once the document has been segmented or "tagged," the
authoring user selects "encrypt" from the menu bar. If the
authoring user 208 has not already logged into the remote server
206, the Plug-In 230 will force a log in to the remote server 206
through the Administrator Utility 228. A log-in screen is provided
and the authoring user 208 must log-in to the server 206. The
server 206 authenticates the authoring user 208 and verifies that
the authoring user 208 is authorized to register documents.
[0043] Once the authoring user has been authenticated, the
authoring user is asked to associate the overall document with a
policy, and this information is communicated to the remote server
1052. This policy becomes the default policy for any portions of
the document which are not tagged and associated with a specific
policy. The Plug-In 230 assigns a unique segment ID for each tagged
segment after the authoring user has tagged all segments and has
instructed the Plug-In 230 to go ahead with the encryption. The
Plug-In 230 transmits the segment IDs to the server 206. The server
206 generates a random encryption key for each segment ID and
communicates the encryption key to the authoring user's computer
222, 1054. The server 206 stores the segment ID, the key associated
with the particular segment ID, and the policy associated with a
particular segment ID in the central database 234, and then
transmits the key to the Plug-In 230 at the authoring user's
computer 222. The Plug-In 230 at the authoring user's computer 222
encrypts the segment, immediately destroys or removes the key from
the authoring user's machine 222, and then deletes the clear text
for the segment from the Plug-In 230. Thus, key lifetime is very
short on the authoring user's machine. The encryption key is never
stored on the authoring user's machine where it is accessible, such
as the hard disk. The key can even be obfuscated while in the
memory of the authoring user's machine. The duration of the key's
existence depends on the speed of the computer which actually
performs the encryption, since the key is destroyed immediately
after the encryption. In the preferred embodiment, 128-bit RC4 is
used for document and segment encryption.
[0044] Once all segments have been encrypted, the Plug-In 230
produces a hash of the entire document and sends the hash to the
server as document identification, 1055. The server 206 stores the
hash with the keys associated with the document. Thus, the document
is never transmitted to the server 206, only the segment IDs and
hash.
[0045] A pop-up window asks the authoring user 208 where he wishes
to store the encrypted document. By default, the encrypted document
overwrites the clear text document on the authoring user's machine
222.
VIEWING, REPLAYING, AND DECRYPTING
[0046] A user wishing to view a document must have installed the
Configuration Utility 226, Administrator Utility 228, and the
Application Interface 230 on his computer 224. The viewing user 216
must be independently registered with the Coordinator 240 as a
user. The viewing user 216 must also have installed the base
software application 232 for viewing the document, such as Adobe
Acrobat Exchange. The viewing user 216 must enter the Configuration
Utility 226 and provide user set up information.
[0047] If the viewing user 216 has not opened the Configuration
Utility 226, the Administrator Utility 228 and the Application
Interface 230, these programs will automatically be opened once the
information to be accessed has been selected, and the system has
recognized that the information is encrypted.
[0048] Once the Configuration Utility 226 has opened, it will
request the user to provide information defining both the viewing
user 216 and the viewing user's computer 224. If the viewing user
216 is a new user, the viewing user 216 will select a button on the
Configuration Utility's interface window indicating that a new user
profile needs to be provided. The Configuration Utility 226 will
provide a query screen to the user and the user will input
identification information, such as a user name. The identification
information will be checked against the information provided to the
server 206 or Coordinator 240 during the independent user
registration process.
[0049] The Application Interface 230 will check to see if the user
is logged onto the remote server 206. If the viewing user 216 has
not logged onto the remote server, the Application Interface 230
provides a pop-up window so that the user can log in to the server.
An SSL tunnel and session key are negotiated, 1056, 1058. The
viewing user's computer 224 provides login and authentication
information to the server 206, 1060. Once logged into the server
206, the Application Interface 230 requests access to the document
or information 1062 by asking the server 206 for the decryption key
for the first segment of the document or information to be
accessed. The server 206 uses the segment ID to check the database
to find the policies associated with the segment and thus to
determine whether the viewing user 216 is authorized to access this
segment or the document as a whole.
[0050] If the viewing user 216 is not authorized to access the
segment, the viewing user 216 is so informed. If the user 216 is
authorized to access the segment, the server 206 sends the
decryption key and options for that segment to the Application
Interface 230 at the viewing user's computer 224 and the
Application Interface 230 decrypts the segment using the decryption
key. After decrypting the segment, the Application Interface 230
immediately discards/destroys the key, renders the decrypted
segment to the screen, and then destroys the decrypted version of
the segment. When the viewing user moves to a different segment,
the process is repeated.
[0051] The Application Interface 230 enforces the options which
were assigned by the authoring user 230 to the segment viewed by
the viewing user 216. For example, if the authoring user 208
assigned that the viewing user 216 cannot print the clear text
document or segment, then the Plug-In 230 disables the print
function of Adobe Acrobat Exchange while the clear text document or
segment is available to the viewing user 216. Other functions which
can be controlled or disabled by the Plug-In 230 are save, copy,
paste, and print with watermark. For other base software packages
such as audio 230, the functions controlled by the Application
Interface 230 could be play, copy, and save unencrypted. Thus,
using the options, the viewing user 216 has no ability to
permanently acquire the clear text document or data.
THE DATABASE
[0052] The secure central database 234 resides on the remote server
206. It may be a distributed or shared database residing on
multiple remote servers 206. In the preferred embodiment the
database 234 is maintained in Berkley DB software. All records
maintained in the central database 234 are encrypted and the
database is password protected. The Coordinator 240 controls the
database 234 and has access to the database 234 using the
password.
[0053] All keys for encryption and decryption are maintained in the
database 234. The database 234 provides a structure for associating
segment IDs with an associated decryption key, policies for
accessing that segment, and options for accessing that segment. The
authoring user 208 may change a policy associated with a segment ID
through the Administrator Utility 228 on his computer. The change
in policy is communicated to the remote server 206 and the database
234 is updated accordingly. The update policy function allows an
authoring user 208 to revoke access to a segment or document by a
user or group of users.
[0054] The authoring user 208 can destroy the decryption key or the
association of a decryption key to a segment or document on the
database 234 using the Administrator Utility 228. By destroying the
decryption key or the association of the decryption key with a
Segment or Document, the authoring user 208 destroys the ability to
decrypt the information, effectively shredding all copies of the
information.
[0055] Regular backups of the database 234 are made without
shutting down the whole database 234.
[0056] One or more preferred embodiments have been described to
illustrate the invention(s). Additions, modifications, and/or
omissions may be made to the preferred embodiment(s) without
departing from the scope or spirit of the invention(s). It is the
intent that the following claims encompass all such additions,
modifications, and/or variations to the fullest extent permitted by
law.
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