U.S. Application No. 08/255,649
`
`USP 8457545
`INFORMATION DISTRIBUTION AND PROCESSING SYSTEM
`Description
`
`This application is a continuation of U.S. patent application Ser. No. 10/073,124, filed Feb. 9,
`2002 now U.S. Pat. No. 7,991,347; which is a continuation of application Ser. No. 09/812,003,
`filed Mar. 19, 2001 (now U.S. Pat. No. 6,349,409); which is a continuation of application Ser.
`No. 09/434,413, filed Nov. 4, 1999 (now U.S. Pat. No. 6,317,785); which is a continuation of
`application Ser. No. 08/939,368, filed Sep. 29, 1997 (now U.S. Pat. No. 6,021,307); which is a
`continuation in part of application Ser. No. 08/644,838, filed May 10, 1996 (now abandoned);
`which is a continuation in part of application Ser. No. 08/279,424, filed Jul. 25, 1994 (now
`abandoned); and application Ser. No. 08/255,649, filed Jun. 8, 1994 (now abandoned); which is a
`continuation in part of application Ser. No. 08/224,280, filed Apr. 74, 1994 (now abandoned); all
`of which are incorporated herein by reference.
`BACKGROUND OF THE INVENTION
`Background1. Field of the Invention
`This application is a continuation in part of application Serial No. 08/224,280 filed April 7, 1994.
`The presentThis invention relates to method and apparatus for distributinggenerally to
`information distribution and processing information, and more specifically relates to method and
`apparatus for preventing unauthorized use ofparticularly to distributing information by partially
`encrypting such informationusing a broadcast channel and a bi-directional communication
`channel.
`With the advance of electronic and communication technology, information conveyed in
`electronic form (“electronic content”) is fast becoming the most economic and reliable way of
`distributing information. However, many information providers are reluctant to distribute
`electronic content because it is very easy to copy and use the information without authorization.
`In spite of the existence of copyright law, experience shows that electronic content are often
`copied and used without paying any royalties to copyright holders. Thus, in order to promote the
`use of electronic conveyance of information, means must be develop to prevent unauthorized
`usage and copying of electronic content.
`
`Methods have been developed to prevent unauthorized copying of electronic content. Several
`years ago, these methods were used by many software developers. However, these copy
`protection methods do not find acceptance in the market place. Consequently, the majority of
`computer software are currently marketed without copy protection.
`2. Description of the Prior Art
`Recently, attention has been turned towards preventing unauthorized uses. For example,
`several companies market “dongles,” or hardware keys, which are attached to a port of a
`computer. A protected software would not execute in a computer without an appropriate key.
`Thus, the protected software could be copied but cannot be used in an unauthorized computer.
`However, many users found that these software and hardware keys cause much inconvenience.
`For example, when a user wishes to remove the software from one computer and execute the
`software in another computer, the associated hardware key has to be moved. So far, no mass
`marketed software uses hardware key to protect against unauthorized uses.
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`Ex. 1029 - Page 1 of 20
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`Groupon, Inc.
`Exhibit 1029
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`Other methods have been developed to prevent unauthorized usage of electronic content.
`One of the methods is disclosed in U.S. Pat. No. 5,010,571 issued to Katznelson. It discloses a
`system for controlling and accounting for retrieval of data from an optical storage medium
`containing encrypted data files from which retrieval must be authorized. The optical storage
`medium is distributed to customers at nominal or no charge. However, in order to decrypt the
`data files, a customer must obtain a decryption key from a remote authorization and key
`distribution station. As a result, unauthorized uses can be prevented. A similar system is
`disclosed in U.S. Pat. No. 4,827,508 issued to Shear. In Shear, the decryption key is stored in a
`secure device in the customer site. The secure device also stores accounting data relating to
`usage of the electronic content. The accounting data is periodically sent to a billing station.
`
`In the above methods disclosed by Katznelson and Shear, vast amount of distributed
`information is encrypted using a single key (or a small number of keys). Thus, if the decryption
`key is inadvertently made public, all these information can be used without paying the
`information providers. Naturally, information providers are reluctant to rely on these methods to
`distribute their valuable asset (i.e., information).
`
`Another problem with these prior art methods is that information providers cannot match
`the security level of encryption to the value of the information. Typically, the security of
`encryption is directly related to the complexity of encryption algorithm and the length of keys.
`The choice of encryption algorithms and the length of keys requires an analysis of the value of
`the information and the costs of encryption. In the methods disclosed by Katznelson and Shear,
`all information are encrypted using the same key. Thus, this key may not match the
`requirements of many information providers.
`
`A further problem of these prior art method is that the encryption algorithm is fixed at the time
`encrypted information is initially distributed. As the installed base of encrypted information
`increases, it becomes difficult to change the encryption algorithm. Thus, these method cannot use
`new cryptographic methods which may be developed in future.
`Recent advances in modem and computer technology allow large amount of digital data to be
`transmitted electronically. A number of information providers (such as newspaper and magazine
`publishers) and on-line information distributors (such as America Online, Dialog and Nexis)
`have formed partnerships to deliver newspaper and other information on-line. In this system, a
`subscriber uses a computer and a modem to connect (e.g., through a regular phone line) to the
`computer of an on-line information distributor. The subscriber can retrieve information,
`including newspaper articles, stored in the computer of the information distributor.
`Another method is disclosed in U.S. Pat. No. 5,247,575 issued to Sprague et al. It discloses that
`encrypted information may be electronically transmitted from a remote site to a receiving device
`in a customer site via wired or wireless means. It also discloses that the decryption key could be
`stored in a removable “key” card. The card can be inserted into the receiving device to decrypt
`the received and encrypted data. This method suffers the same defects described above in
`connection with Katznelson and Shear. In addition, this method requires a communication
`channel having a large bandwidth for transmitting the encrypted information.
`On-line delivery of newspaper has many advantages. For example, the information can be
`updated throughout the day while the printed version is printed only once or twice a day. Further,
`it is possible to do text-based searches on the information. However, it is found that on-line
`deliver of newspaper and other information is slow. For example, a subscriber has to wait many
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`seconds for a newspaper article to be delivered. The quality of the electronic newspaper is low.
`For example, in order to reduce storage and communication requirements, graphic images
`appeared in the printed version are not universally supplied in the on-line version of newspaper.
`One of the reasons for such poor performance is the limited bandwidth of communication
`channels used by on-line information distributors. Another reason is that information is centrally
`processed by the computer at the site of the information distributor, with the result that each
`subscriber only gets a small slice of the time of the computer.
`
`Another way to communication information on-line is through the Internet, which is a worldwide
`interconnection of millions of computers, from low end personal computers to high-end
`mainframes. An important development in the Internet is the World Wide Web (the “Web”). The
`Web is a wide-area hypermedia information delivery and retrieval system aimed to give
`universal access to a large universe of documents. When the Web was first developed around
`1989, it was known to and used by the academic/research community only as a means for fast
`disseminating of information. There was no easily available tool which allows a technically
`untrained person to access the Web. An important development is the release of a Web
`“browser” around 1993. It has a simple but powerful graphic interface. The browser allows a
`user to retrieve web documents and navigate the Web using simple commands and popular tools
`such as point-and-click. Because the user does not have to be technically trained and the browser
`is easy to use, it has the potential of opening up the Internet to the masses.
`
`A document designed to be accessed and read over the web is called a web page. Each web page
`must have an address in a recognized format—the URL, or Uniform Resource Locator—that
`enables computers all over the world to access it. Each web page has an unique URL. A web
`page typically contains both text and images. It is also possible to include audio and movie data.
`
`The Web faces the same problem as the regular on-line delivery of information. This is because
`most people use the above described modem to access the Internet. Thus, the data transfer rate of
`the Web is also limited. Because multimedia data (comprising a combination of text, graphic,
`video and/or audio) has a large data size, even when compressed, it could take a long time to
`retrieve a document from the Web. Further, it is difficult to prevent unauthorized persons from
`access a web page because more than 20 million people in the world has access to the Internet.
`
`Consequently, there is a need to have an improved system for distributing information
`electronically.
`SUMMARY OF THE INVENTION
`The present invention uses two channels to deliver digital information: a broadcast channel and a
`bi-directional channel. The broadcast channel is used to deliver the bulb of the digital
`information to subscribers. The amount of information delivered is preferably sufficient to
`satisfy the needs of a large number of subscribers so that they do not have to obtain additional
`information using the bi-directional channel. The broadcast information is stored on fast storage
`media located at subscriber sites. As a result, search and retrieval of the broadcast information is
`quick. Further, the broadcast information is processed locally using a dedicated on-site processor
`instead of relying on the computers of the information distributors. As a result, the load on the
`computers of the information distributors is reduced. If the subscribers desire to receive
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`additional information relating to the broadcast information, the bi-directional communication
`channel is used to transmit the request and the requested information.
`Broadly stated, the invention involves a method and system for distributing and
`processing digital information. The digital information is separated into two portions. The first
`portion is a clear portion and the second (residual) portion is encrypted. The clear and the
`encrypted portions are sent to a processing system which decrypts the encrypted portion. The
`clear and decrypted portion is combined to obtain a result which is substantially the same as the
`original digital information.
`
`In one embodiment of the present invention, the clear portion is distributed to customers
`at no or nominal cost. The residual portion will be stored in a central station. When a customer
`wishes to use the digital information, the central station encrypts the residual portion using an
`encryption-decryption key-pair generated at that time. The encrypted portion and the decryption
`key are sent to the processing system in a secure manner. As a result, different keys can be used
`to encrypt and decrypt the same information at different times.
`
`One feature of the present invention is that the clear portion is selected in a way to render
`the reconstruction of the original digital information difficult if the residual portion is not known.
`Thus, a customer will not be able to reconstruct the original digital information based on the
`clear portion. As a result, unauthorized use of the digital information is prevented.
`
`In the present invention, the information providers control the choice of encryption algorithms
`and keys. Further, algorithms and keys can be changed at will.
`The distribution costs of broadcast channels are typically much lower than that of a bi-directional
`communication channel. Consequently, the major portion of information is delivered using low
`cost distribution channels. For a large number of subscribers, the broadcast information will
`provide all the information they normally need. Thus, expensive bi-directional communication
`channels are used only occasionally.
`
`These and other features and advantages of the present invention will be fully understood by
`referring to the following detailed description in conjunction with the accompanying drawings.
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a block diagramschematic drawing showing an embodiment of an information
`distribution and processing system in accordance withof the present invention.
`
`FIG. 2 is A flow chart showing the application of the present invention to JPEGshows a
`newspaper article as displayed on a monitor of the information distribution system shown in FIG.
`1.
`Fig. 3 is a schematic diagram showing the application of the present invention to video data.
`FIG. 2B shows the contents of the broadcast information which corresponds to the newspaper
`article of FIG. 2A.
`
`FIG. 4 is a block diagram of a software3 shows another embodiment of the information
`distribution and processing system of the present invention.
`
`FIG. 4 shows an embodiment of the present invention used in a data communication network.
`DETAILED DESCRIPTION OF THE InventionPREFERRED EMBODIMENT
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`The present invention comprises a novel information distribution and processing system and
`related methods. The following description is presented to enable any person skilled in the art to
`make and use the invention. Descriptions of specific applications are provided only as examples.
`Various modifications to the preferred embodiments will be readily apparent to those skilled in
`the art, and the general principles defined herein may be applied to other embodiments and
`applications without departing from the spirit and scope of the invention. Thus, the present
`invention is not intended to be limited to the embodiments shown, but is to be accorded the
`widest scope consistent with the principles and features disclosed herein.
`
`The present invention can be used to solve the above described problem of digital information
`delivery. It uses two channels to deliver digital information: a broadcast channel and a bi-
`directional channel. The broadcast channel is used to deliver the bulb of the digital information
`from a source to subscribers. The time for broadcasting is preferably during a time of low
`communication load (e.g., off-peak hours). Upon receiving, the broadcast information is stored
`on storage media located at subscriber sites. If the subscribers desire to receive additional
`information relating to the broadcast information, the bi-directional communication channel is
`used to transmit the request and the requested information.
`
`The data transfer rate of the storage media (more than a million bytes per second) could be
`hundreds of times faster than that of a modem. As a result, search and retrieval of the broadcast
`information is quick. Further, the broadcast information is processed locally using a dedicated
`on-site processor instead of relying on the computers of the information distributors. As a result,
`the load on the computers of the information distributors is reduced. Even though the requested
`information is delivered using a regular low bandwidth communication channel, the performance
`of the system would not be severely affected because the requested information is only a small
`fraction of the broadcast information.
`
`In one embodiment of the present invention, the broadcast information can be sent in the clear
`while the requested information (which may contain commercially valuable information) is
`encrypted. Because the amount of requested information is a small fraction of the broadcast
`information, there is no need to use much computer resource to process the requested (and
`encrypted) information. In a different embodiment of the invention, the broadcast information is
`encrypted using a simple algorithm while the requested information is encrypted using a
`complex algorithm. Even though extra computer resource is used to decrypt the broadcast
`information, this embodiment may be useful for the case where it is not desirable for the public
`to view the broadcast information.
`
`It should be noted that the word “channel” is not limited to a specific kind of physical
`communication link. The word “channel” merely means a path for communicating information.
`The term “broadcast channel” means a path allowing an information source to deliver digital
`information to many recipients almost simultaneously. The term “bi-directional channel” means
`a path allowing one-to-one interactive communication between a source and a recipient. These
`two “channels” could use the same physical communication link (e.g., telephone lines, television
`cable lines, wireless, optical links, etc.) to perform their respective functions. That is, the same
`physical communication link can support both broadcast and bi-directional channels.
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`FIG. 1 is a block diagram of an information distribution and processing system 300250 in
`accordance with the present invention. System 300lcontains a central station 302 which is
`connected via a communication link 3p3 to In this embodiment, system 250 is designed to
`electronically distribute digital newspaper. It should be pointed out that system 250 can also be
`used advantageously to distribute other types of digital information. System 250 contains a
`plurality of processing units located in subscriber sites,units (such as units 310 and 340.
`Processing units 310 and 340 are also252 and 254) each connected to a bi-directional
`communication links 306 and 307, respectively. Communication links 306 and 307 are
`preferably not connected to central station 302, but may be connected thereto when needed.
`Communication links 303, 306, and 307 could be wired or wireless, remote or local, point-to-
`point or broadcasting.channel (e.g., modems 256 and 258 coupled to units 252 and 254,
`respectively) and a satellite transponder 260 for broadcasting digital data to these subscriber
`units. Modems 256 and 258 may be coupled to a database 259 via line-based or wireless
`telephone communications. In system 250, satellite transponder 260 is used to broadcast the
`content of a newspaper to the subscriber units while telephone modems 256 and 258 allow
`delivering additional information (stored in database 259) to subscriber units 252 and 254,
`respectively, on a demand basis.
`Digital information to be distributed is separated into clear (i.e., unencrypted) portions
`and residual portions in accordance with methods described below. The residual portions are
`essentially the digital information with the clear portions removed. The clear portions are sent to
`processing units 310 and 340 via links 306 and 307, respectively. The residual portions are
`stored in central station 302 and will be encrypted before sending to processing units 310 and
`340 upon demand. Central station 302 also takes care of various accounting and bookkeeping
`functions.
`
`The structure of the processing units are substantially the same. Thus, only one of the
`units, in this case, unit 310, will be described in detail. Unit 310 contains a general processor 312
`connected to a secure processor 314 through a communication link 316 (which could be wired or
`wireless). Secure processor 314 is connected to communication link 303 through a line 318.
`Secure processor 314 is enclosed by a protective mechanism so that unauthorized access
`(physical and electrical) to the internal circuitry can be prevented. Secure processor 314 is used
`to decrypt encrypted portions and temporarily store secret information (such as decryption keys
`and usage data). Unlike secure processor 314, general processor 312 does not have to be placed
`in a secure enclosure. Thus, it could be a conventional computer.
`
`In system 300, general processor 312 is used to process the unencrypted data (e.g.,
`decompression, filtering, and error correction) received from communication link 306 while
`secure processor 314 is used to process encrypted data (e.g., decryption and decompression)
`received from communication link 303. Secure processor 314 and general processor 312 can
`communicate with each other using communication link 316. This link does not have to be a
`secure communication link.
`
`Secure processor 314 preferably contains a unique device ID. This device ID is preferably
`permanently stored in a nonvolatile memory 319, such as a ROM. The device ill allows secure
`processor 314 to identify itself to other devices, such as central station 302.
`The structure of these subscriber units are substantially identical; consequently, only one of these
`units, such as unit 252, is described in detail. Unit 252 contains an antenna 266 for receiving
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`broadcast signals from satellite transponder 260, a signal/data processor 268 for performing
`signal and data processing functions, a monitor 270 for displaying the digital newspaper, and an
`input device 272 (such as a keyboard and/or a mouse).
`A typical operation of system 300 is now described. Information data is separated in
`residual data and unencrypted data according to methods ‘described below. The residual data is
`preferably a small percentage of the unencrypted data. Unencrypted data 326 preferably contains
`an information ID 327 and a content portion 328. Content portion 328 could contains data
`relating to video, text, audio, or their combination.
`
`Unencrypted data 326 is sent to general processor 312 of processing unit 310 through
`communication link 306. General processor 312 sends the information ID 327 to secure
`processor 314, which in turn forwards it to central station 302 via communication link 303. At
`the same time, the device ID stored in memory 319 is also sent to central station 302 so that it
`can keep track of usage and billing information. Central station 302 encrypts the corresponding
`residual data and sends the encrypted data to secure processor 314 via communication link 303.
`Because link 303 is not a secure link, special methods, described below, need to be used for
`central station 302 to securely send the corresponding decryption key to secure processor 314 ..
`Secure processor 314 decrypts the received encrypted data and combines the result with the
`unencrypted data so as to reconstruct the full digital information.
`
`The key used for encrypting and decrypting the encrypted data could be different for each
`processing and communication session described above. Thus, it is more difficult for
`unauthorized persons to obtain the decryption key to decrypt the encrypted data. Even assuming
`that a few decryption keys are inadvertently disclosed to unauthorized persons, only a few pieces
`of information is compromised. This is different from the system disclosed in the prior art, where
`inadvertent disclosure of a single decryption key may compromise vast amount of information.
`
`Processing unit 310 also contains an output unit 322, which may be connected to general
`processor 312 or secure processor 314. Depending on the information processed, output unit 322
`may be a printer, loudspeaker, TV, or LCD display. In situations where it is not desirable to
`expose the reconstructed information, output unit 322 should be securely connected to secure
`processor 314.
`
`Even though Fig. 1 shows secure processor 314 as a single block, the function of secure
`processor 314 could be carried out in several components. For example, the device ID could be
`stored in a smart card 332 which is removably connected to processing unit 310. Smart card 332
`should be protected from unauthorized intrusion.
`
`Methods for separating information into unencrypted and residual portions are now
`described. It has been observed that information generally has a certain degree of correlation. At
`one extreme is information that is highly correlated. An example is video information which
`consists of a series of pictures depicting time progression of a scene. Each picture typically
`differs slightly from an adjacent picture in the series because the time difference in the scene
`depicted by adjacent pictures is typically less than 0.1 second. As a result, video information
`contains many pictures which are substantially the same. Consequently, it is easy to construct a
`picture missing from the series by interpolating from the pictures prior and subsequent to the
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`missing picture. This type of information is considered to have a high degree of temporal
`correlation.
`
`Video information also has another type of correlation. The spatial variation of a picture
`is typically very gentle. For example, if the picture is a human swimming in water, there is little
`variation (in terms of color and intensity) in the portion of the picture relating to water.
`Consequently, it may be easy to recreate a missing portion of a picture by interpolating from
`portions of the picture surrounding the missing portion. This type of information is considered to
`have a high degree of spatial correlation.
`
`At the other extreme is information for which it is difficult to create a missing portion
`from other portions. This type of information has a low degree of correlation. An example of this
`type of information is the binary code of a piece of software. Typically, it is difficult to recreate a
`missing byte (or a series of missing bytes) from other bytes in the binary code.
`
`In the middle of this spectrum of correlation is text information. The structure of many
`languages dictates that redundant words or letters be used at predetermined positions of a
`sentence. Thus, it is possible to guess missing words and letters in a sentence. For example, the
`grammar of the English language imposes a set of rules which includes putting the letter “s” at
`the end of a noun to designate plural quantity. In many sentences, the noun is not the only place
`where plural quantity is indicated. For example, the sentence “there are two birds” uses the word
`“two” to indicate the existence of more than one bird, in addition to the letter “s” attached to the
`word “bird.” Thus, the letter “s” at the end of the word “bird” is correlated to the word “two” in
`the above sentence. Similarly, the word “are” is correlated with the word “two.”
`
`Information can also be classified according to its effect on intended uses if a portion of
`the information is missing. At one extreme is information which would be useless if a small
`portion is missing. An example is the binary code of a piece of software. A computer is unlikely
`to successfully execute the software if the binary code has a few erroneous bytes. This type of
`information is considered to be error intolerant. At the other extreme is information that degrades
`gracefully. For example, when noise of TV signal increases (i.e., portions of video information is
`missing or has erroneous values), color TV pictures often become monochrome. However, it is
`still possible to watch and comprehend the TV pictures, even though they are less pleasing to the
`eyes. This type of information is considered to be error tolerant. Error toleration can also be
`different depending on spatial or temporal types of errors.
`
`It should be pointed out that even though the degree of error tolerance has some
`relationship to the degree of correlation of information, it does not depend solely on the degree
`of correlation. For example, a person typically does not tolerate a small distortion in a familiar
`song while may tolerate a large distortion in a new song, even though the degree of correlation of
`these two songs are the same. As another example, a reader is likely to tolerate a large number of
`missing words in a newspaper article. On the other hand, the same reader probably would not
`tolerate the same percentage of missing words in a poem. Thus, even though the degree of
`correlation of the newspaper article and poem may be the same (because they follow essentially
`the same grammar rules), the degree of error tolerance is different. This is because error
`tolerance depends, to a certain extent, on subjective considerations.
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`In the prior art information distribution and processing systems using cryptography, every
`bit of information is encrypted. One aspect of the present invention is the realization that it may
`not be necessary to completely encrypt the information, especially when it has a low degree of
`correlation. This is because it is often difficult to reconstruct the residual portions based on the
`clear portions of information. In addition, information that has a low degree of error tolerance
`may only need to be encrypted at a few critical places (e.g., the destination address of a jump op
`code, or the last name field of a customer database). This is because a user would not accept the
`information if a small portion is missing or erroneous. Thus, even though most of the
`information is in the clear, it is still not commercially useful if isolated portions are unavailable
`because they cannot be decrypted (i.e., people are still willing to pay a high price to obtain the
`full information, even though they already have 99 percent of the information). Since only a
`small portion of information need to be decrypted, the amount of computation power required to
`decrypt the information is reduced.
`
`Encrypting a portion of information may also help to reduce the computation power
`required for other signal processing tasks. As an example, information which is massive and
`highly correlated (e.g., video information) is often compressed in order to reduce the amount of
`memory space used for storing and the bandwidth used for transmitting the information. Many
`compression methods make extensive use of the correlative nature of information. However,
`many encryption methods have a tendency to randomize information. For example, if the plain
`text is a string of identical letters, the encrypted text using algorithms such as DES may be a
`string of letters in which every letter is different. Consequently, it may be more difficult to
`compress the encrypted text.
`
`The word “encryption” is used broadly in the present invention to include different ways
`of transforming information so that it is difficult for an unauthorized person to correctly
`understand the information. It includes transformation in which a key is required, such as public
`key and secret key encryption methods. It also includes scrambling information according to a
`secret algorithm without using a particular parameter which may be classified as a “key.”
`
`The word “information” is used broadly in the present invention to include data that is organized
`in some logical manner. Examples of information include video signal, audio signal, picture,
`graphic, computer software, text, database, and multimedia composition.
`Signal/data processor 268 contains a transponder interface 282 for processing transponder signal
`received from antenna 266. Transponder interface 282 preferably contains a low noise receiver
`for receiving high frequency (e.g., C or Ku band) transponder signal and a universal data
`interface for converting the transponder signal to digital data. The retrieved data is stored in
`nonvolatile storage 284, such as a hard disk or solid state flash memory. Preferably, satellite
`transponder 260 broadcasts the newspaper data at predetermined times. Thus, a real-time clock
`286 is preferably used to turn an interface 282 at the predetermined times. Processor 268
`contains a microcomputer 290 which coordinates the operation of clock 286, nonvolatile storage
`284, and interface 282. Microcomputer 290 preferably contains a central processing unit (CPU),
`random access memory (RAM) and peripheral interface devices. Proces