Abstract:
A protected content distribution system utilizes media-based copy protection to support online distribution of protected content in a secure and legitimate fashion. Using a media-based copy protection scheme based on broadcast encryption, the protected content distribution system realizes online distribution of protected content such as, for example audio files, movies, etc, authorizing consumption of unlicensed content by transfer of a unique encrypted key to the protected media. This transaction is fast, involving the transfer of an encrypted binding key rather than the protected content. Content is enabled through a unique encrypted key on protected media accessed through a device separate from the media driver.

Description:
FIELD OF THE INVENTION 
   The present invention generally relates to a system for using broadcast encryption techniques to license encrypted protected content such as, for example, music, movies broadcast content (TV), games, ring tones, and ebooks, to individual users. More specifically, the present invention pertains to a method utilizing media-based copy protection to enabling a user to distribute copyrighted or protected content in a secure and legitimate fashion through superdistribution, an electronic wallet, or rental. 
   BACKGROUND OF THE INVENTION 
   The entertainment industry is in the midst of a digital revolution. Music, television, and movies are increasingly becoming digital, offering new advantages to the consumer in quality and flexibility. At the same time the digital revolution also comprises a threat since digital data can be perfectly and quickly copied. If consumers may freely copy entertainment content and offer that content on the Internet, the market for entertainment content would evaporate. 
   The rapid growth in the distribution of digital content over the Internet, such as MP3s and DivX encoded movies, is especially alarming to content owners. These highly controversial and unauthorized distribution channels have caused an increase in demand from the entertainment industry for methods to protect their multi-million dollar content. Developing a content protection system that offers content owners an end-to-end solution they can use to securely distribute their copyrighted content is becoming increasingly important as the amount of content shared across the Internet grows exponentially each year. 
   One conventional approach for distribution of electronic content over a network infrastructure uses prepaid media (reference is made to U.S. Pat. No. 6,434,535 B1). A user obtains a prepaid media that comprises a unique key. The user contacts a specified server with the unique key and a remaining balance of the prepaid media. If the media and the remaining balance are valid, the user can download to the media a selected item of protected content that has been encrypted with the unique key. However, this approach does not allow a user to obtain the protected content from sources other than the specified server nor does this approach provide a method for a user to obtain authorization to use an item of protected content obtained through an unauthorized source. 
   Recently, developments in consumer electronics have created an alternative to traditional digital rights management systems. New recording and playing devices that use this new method, known as CPRM (Content Protection for Recordable Media) technology, have reached the market. It is now possible to directly record content protected in CPRM to writable media. If the recording is prepared in a server, the client needs no special keys or tamper-resistance. This method of content protection utilizes broadcast encryption. Devices do not need to have a conversation to establish a common key. Recent advances in broadcast encryption have made it as powerful as public-key cryptography in terms of revocation power. Because of its one-way nature, broadcast encryption is inherently suited to protect content on storage. 
   Once the client receives the encrypted content using CPRM, the interaction between the content server and the client side module is complete. The server is now free to focus on other requests. On the client side, CPRM requires that the encrypted content be recorded onto a physical piece of media, such as a recordable optical disk. This recording is performed in such a way that the encrypted content can only be played by a compliant device while it is on that particular piece of media. Consequently, encrypted content copied to another physical piece of media cannot by played by a compliant device. 
   CPRM devices use the media key block and media ID located currently on blank DVD recordable disks to calculate a media unique key. The media unique key is used to encrypt title keys. In turn, the title keys encrypt the content stored on the DVDs. Encrypting the title keys in the media unique key causes the title keys to become cryptographically bound to the particular piece of physical media on which the content is burnt. This prevents the encrypted content from being decrypted and accessed from any other physical piece of media. 
   Although this technology has proven to be useful, it is desirable to present additional improvements. Conventional techniques for copy protection of protected content prevent the use of protected content through superdistribution, i.e., file-sharing. For example, a user has a licensed copy of a protected content such as a movie on a DVD. The user shares the content with another user such as a friend over the Internet. The friend copies the content to a protected media such as a DVD-RAM. Conventional copy protection techniques prevent the friend from playing the content. However, conventional copy protection techniques do not allow the friend to purchase a license for use of the acquired content. By limiting the response of the protected media to “do not play”, conventional copy protection techniques limit the sale of protected content through channels such as superdistribution. 
   What is therefore needed is a system, a service, a computer program product, and an associated method for enabling consumers to distribute protected content using protected media in a secure and legitimate fashion. The need for such a solution has heretofore remained unsatisfied. 
   SUMMARY OF THE INVENTION 
   The present invention satisfies this need, and presents a system, a service, a computer program product, and an associated method (collectively referred to herein as “the system” or “the present system”) for enabling authorized use of distributed content on a protected media. The present system utilizes media-based copy protection to support online distribution of protected content in a secure and legitimate fashion. 
   Using a media-based copy protection scheme based on broadcast encryption, the present system realizes online distribution of protected content such as, for example audio files, movies, etc. The protected content is also referenced herein as digital content, copyrighted content, or content. Currently, standards utilizing broadcast encryption comprise video content protection system (VCPS), content protection for recording media (CPRM) and advanced access content system (AACS). While the present system is described in terms of CPRM, it should be clear that the present system may be applied to, for example, any copy protection system utilizing broadcast encryption, or any content protection system that allows digital content to be encrypted and associated with physical media. 
   The present system enables media-based superdistribution of content in a secure and legitimate fashion. For example, a user owns a licensed copy of content such as a movie. The user shares that movie through the Internet with a friend. The friend copies the movie to a protected media such as, for example, a DVD-RAM. Conventional copy protection systems simply prevent the movie from playing because a “binding key” (a unique encrypted key) is not present on the protected media. In contrast, the present system directs the friend to one or more websites from which a license for use of the content may be purchased and the binding key obtained. In this manner, the present system allows superdistribution of content in a secure and legitimate fashion while protecting the rights of the content owner, enabling new marketing techniques for protected content through superdistribution. 
   The present system uses a simple transaction flow to a licensing server to enable authorized superdistribution of protected content. A user receives an item of unlicensed content and transfers that unlicensed content to a protected media. Alternatively, the user receives the protected media with the unlicensed content already on the protected media. The user attempts to play the unlicensed content on a media device. The media device directs the user to a website that presents one or more links to e-commerce businesses where a transaction can be performed to enable the unlicensed content. The unlicensed content is enabled through transfer over the Internet of an encrypted binding key to the protected media. 
   The unlicensed content is distributed outside of channels controlled by conventional content distributors. Consequently, the website provides a link from the user to an authorized distributor for that unlicensed content. A media device provides to the website a content ID for the unlicensed content. The website looks up a list of electronic retailers for that unlicensed content and presents that list to the user. The user can then select an electronic retailer based on personal preferences of the user. Because the user already has possession of the unlicensed content, this transaction involves only the transfer of an encrypted binding key. Consequently, the transaction is fast, requiring moderate bandwidth capability on the part of the server. 
   The user may be directed to the website through a link on a message presented by the player to the user, requiring the user to click on the link to navigate to the website. The media player may automatically launch the website for the user. The website may further operate as an e-commerce business from which the content may be purchased or rented. The superdistribution model allows operation of a peer-to-peer file-sharing service that enables users to swap content over a network in a secure and legitimate fashion. As an advantage, only one protection mechanism is required to protect the content during distribution and media-based playback. 
   In one embodiment, content is enabled through a binding key on a hardware copy protection device such as a dongle. This dongle model does not depend on the superdistribution model. In conventional terms, a dongle is a device that attaches to a computer and controls access to a particular application or other content by the user. In this embodiment, a protected media (further referenced herein as a protected media dongle) is used as the dongle. For example, a PC comprises an SD card adapter; the SD card acts as the protected media dongle. The protected content is bound through encryption to the protected media dongle that is required to be present when the protected content is enabled. The protected media dongle represents a physical token of a license to consume content. The license may represent purchase of the content, rental of the content, promotional give-away of the content, etc. 
   A user receives the protected content, for example, through a download, through an e-mail attachment, by copying from another media, etc. The protected content is copied onto a storage device such as, for example, a hard drive. An application or media player plays or otherwise “consumes” the content. To consume the content, the application requires a key. This key is encrypted and stored on the protected media dongle. Consequently, presence of the protected media dongle is required for the application to obtain and decrypt the key. The key can be obtained via the superdistribution model as described herein, or it can be acquired as part of a regular recording operation. In this manner, a user may have many copies of the content in many locations, but only be able to use or consume the copy that has access to the key on the protected media dongle. In this embodiment, content comprises any content that is consumed on a PC or other media player such as, for example, multimedia content, executable content such as games, etc. The key is distributed independently from the protected media dongle in encrypted form and bound to the protected media dongle using a binding mechanism. 
   An exemplary protected media dongle is a SD card. A conventional SD card has a storage capacity on the order of 64 MB, 258 MB, etc. While the SD card is too small to store, for example, an application, the SD card can store many different keys. A typical key is on the order of approximately 20 bytes. Consequently, an SD card with capacity of 64 MB can contain the keys for 3 million different items of content such as games, movies, applications, databases, video, audio, or any other type of content requiring secure distribution. 
   This embodiment leverages inexpensive copy protection features provided by protected media to protect any form of content on a PC. Rather than trying to protect content on the PC, this embodiment protects a key on the protected media dongle. Consequently, this embodiment extends copy protection capabilities of protected media to the PC and hard drives. 
   This embodiment further provides a portability feature in that content can be copied to another PC. However, a key on a protected media dongle is required for each copy being used at any one time; i.e., if a user has purchased a license for one copy of the content, only one copy of the content may be used at a time. For example, a user may have a vacation home. The user can make a copy of his entire library of video and audio files and store that copy in his vacation home. The user takes his protected media dongle with him to his vacation home and has access to that entire library. However, the content in his regular home cannot be played without the protected media dongle. Only one of the copies of the library can be played at any one time. The ability to play another copy of the library requires obtaining additional keys for the content of the library and storing those additional keys on another protected media dongle. 
   In another embodiment, the present system performs as an electronic wallet. The electronic wallet uses the protection capabilities of protected media to manage budget information. The budget information enables a predetermined number of transactions or a predetermined dollar value that can be spent on transactions. Protected content stored on the protected media is the available budget. The protected media manages a state of the budget, protecting the budget from being copied to other media. The protected media further protects the budget from being “rolled back”; i.e., preventing a user from making a copy of the electronic wallet at an initial value, consuming a portion of the electronic wallet, and the restoring the electronic wallet with the backup to the initial value. 
   The electronic wallet may be purchased by a user or given to the user as, for example, a promotional give-away. Transactions performed using the electronic wallet can be anonymous on the part of the user or may comprise information about the user. The value of the budget on the electronic wallet may be refilled through, for example, an online transaction. The information regarding the value of the budget on the electronic wallet is stored on the electronic wallet rather than at a central processing system which allows the protected wallet to be used in a disconnected environment. To add value to an electronic wallet, a server requires access to the electronic wallet through, for example, a network such as the Internet. 
   An electronic wallet using protected media comprises copy protection and state management. Copy protection prevents duplication of the electronic wallet, eliminating a possibility of the user simply duplicating an electronic wallet unlimited times for unlimited access to the budget on the electronic wallet. State management prevents a user from restoring the budget of the electronic wallet with a copy of the electronic wallet to “roll back” the budget of the electronic wallet to a previous value. 
   For example, a user has received an electronic wallet loaded with an initial credit of three plays as a promotion. The user may then download a protected movie and use the balance managed on the electronic wallet to play the content three times. The user, in an attempt to obtain more plays of the movie than allowed by the promotion, makes a copy of the electronic wallet with three plays in the budget of the electronic wallet. The protected media comprises a key that is required to operate the electronic wallet and thus operate the movie. When the contents of the electronic wallet are copied to any other form of media, the key from the protected media is not available to the electronic wallet; consequently, the copy of the electronic wallet is not functional. 
   In another attempt to obtain more plays of the movie than allowed by the promotion, the user plays the movie three times and then attempts to back up the electronic wallet with the copy of the electronic wallet previously made. 
   A balance available on the electronic wallet is decremented by an application that has recording capabilities. In one embodiment, decrementing the balance is performed by the application provided the application has access to encrypted keys for modifying the electronic wallet. In another embodiment, decrementing the balance is performed online using a server with access to encrypted keys for modifying the electronic wallet. Even if the electronic wallet is modified by a server online, an electronic wallet purchased with cash requires no personal information from the user. The transaction can be anonymous because the presence of the electronic wallet in a form of protected media is sufficient validation for the budget on the electronic wallet. Consequently, the electronic wallet leverages copy-protection features of inexpensive protected media that enables anonymous transactions in an anonymous fashion. 
   The state of the electronic wallet represents any value that can be decremented by the present system. Further the state of the electronic wallet may be incremented by a transaction with, for example, an authorized server or an authenticated application. Any application can “reload” the electronic wallet provided the application has the necessary device keys to write to the protected media. 
   The electronic wallet can be used for generational management of content, limiting the number of copies a user may make of the content. The electronic wallet can be used to provide a user with a number of purchases or a value of purchases from either an e-business or standard retailer with access to the Internet for purchases. 
   In a further embodiment, the present system performs as a protected media subscription container. During the subscription process, a media ID on a protected media designates the protected media as a rental media associated with a specific user. The user can copy content to the rental media from a rental service either remotely or locally. As an example, the user may download content from the rental service to the rental media via the Internet. The user may further copy content to the rental media locally from a device such as a kiosk in a rental retailer. 
   The rental media is a “container” for rented content. The terms of the subscription can, for example, limit the user to possession of three items of content at any time. To obtain possession of another item of content, the user writes over one of the three items of content in the rental media. The user is allowed unlimited downloads to a rental media that is registered with the provider of the rented content. However, the user is limited to possession of a predetermined number of items of rented content at any one time. Alternatively, the maximum number of concurrent rentals might be enforced by the capacity of the media itself. In this scenario, the user has unlimited downloads to the media registered as a rental container. However, since the capacity of the media is limited, the user will have to overwrite old content when downloading new one. 
   The present system uses the unique identification of protected media to provide a secure and legitimate method for operating a content rental business without a need for a trusted clock to limit a time window in which the content may be consumed. Further, the subscription rental model allows use of Internet downloads of content in a secure and legitimate manner, eliminating a need for mailing content to the user and back to the content rental business. 
   The present invention may be embodied in a utility program such as protected content distribution system utility program. The present invention also provides means for the user to obtain a license for consumption of protected content on a protected media. The user invokes the protected content distribution system utility program to enable use of the protected content after obtaining an encrypted key for the protected content. The present invention further provides means for the user to enable use or consumption of protected content on a media device through an encryption key stored on a protected media. The user invokes the protected content distribution system utility program to enable use of the protected media as a protected media dongle from a dongle media device external to a media device on which the protected content is operated. Furthermore, the present invention provides means for a user to obtain and consume a budget on the protected media. The user invokes the protected content distribution system utility program to manage the budget on the protected media. The present invention further provides means for a user to operate the protected media as a rental container. The user invokes the protected content distribution system utility program to manage a rented protected content on the protected media. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The various features of the present invention and the manner of attaining them will be described in greater detail with reference to the following description, claims, and drawings, wherein reference numerals are reused, where appropriate, to indicate a correspondence between the referenced items, and wherein: 
       FIG. 1  is a schematic illustration of an exemplary operating environment in which a protected content distribution system of the present invention can be used for enabling use of protected content obtained through superdistribution; 
       FIG. 2  is comprised of  FIGS. 2A and 2B , and represents a process flow chart illustrating a method of operation of the protected content distribution system of  FIG. 1  in licensing protected content obtained through superdistribution; 
       FIG. 3  is a schematic illustration of an exemplary operating environment in which a protected content distribution system of the present invention can be used for enabling the optional use of protected content through a protected media dongle; 
       FIG. 4  is a process flow chart illustrating a method of operation of the protected content distribution system of  FIG. 3  in using the protected media dongle of  FIG. 3 ; 
       FIG. 5  is a process flow chart illustrating a method of operation of the protected content distribution system of  FIG. 3  in consuming protected content; 
       FIG. 6  is a schematic illustration of an exemplary operating environment in which a protected content distribution system of the present invention can be used as a protected media electronic wallet; 
       FIG. 7  is comprised of  FIGS. 7A and 7B  and represents a process flow chart illustrating a method of operation of the protected content distribution system of  FIG. 7 ; 
       FIG. 8  is a schematic illustration of an exemplary operating environment in which a protected content distribution system of the present invention can be used as a protected media rental container; 
       FIG. 9  comprises  FIGS. 9A and 9B  and represents a process flow chart illustrating a method of operation of the protected content distribution system of  FIG. 1  operating as a protected media rental container for rental of protected content. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   The following definitions and explanations provide background information pertaining to the technical field of the present invention, and are intended to facilitate the understanding of the present invention without limiting its scope: 
   Content: copyrighted media such as, for example, music, movies, audio files, video files, e-books, databases, applications, games, etc., presented in a digital format on electronic devices. 
   Dongle: A device that attaches to a computer to control access to a particular application or item of protected content. 
   Internet: A collection of interconnected public and private computer networks that are linked together with routers by a set of standard protocols to form a global, distributed network. 
   Protected media: Any form of media having a copy-protection technology such as, for example, secure MMC, a flash memory card, a secure digital memory card (SD card), a digital versatile disk with random access memory, a digital versatile disk with read/write capability (DVD-R/W, DVD+RW), and high definition digital versatile disk, and a hard disk digital versatile disc (HD-DVD), etc. 
   Superdistribution: Distribution of content from one user to another through channels other than as a sale from a commercial entity to a consumer, for example, when a user shares a copy of content with a friend. Examples of superdistribution comprise file-sharing schemes such as Napster®, Kazaa®, etc. 
   URL (Uniform Resource Locator): A unique address that fully specifies the location of a content object on the Internet. The general format of a URL is protocol://server-address/path/filename. 
   World Wide Web (WWW, also Web): An Internet client-server hypertext distributed information retrieval system. 
     FIG. 1  portrays an exemplary overall environment in which a system, a service, a computer program product, and an associated method (“the system  10 ”) for distributing protected content using protected media according to the present invention may be used. System  10  includes a software programming code or computer program product that is typically embedded within, or installed on a media device  20 . 
   A media device  20  can read and write to the protected media  15 . The media device  20  is any device that can play or execute protected content  25  on the protected media  15 . A user receives the protected content  25 ; the protected content  25  is an unauthorized copy of copyrighted digital content. For example, the user may receive the protected content  25  by downloading the protected content  25  from a file-sharing website, as an attachment in an e-mail, etc. The user copies the protected content  25  onto an empty protected media  15 . Alternatively, the user may receive the protected media  15  from another source with the protected content  25  already on the protected media  15 . 
   The user attempts to play the protected content  25  on the protected media  15  in the media device  20 . To play, read, execute, or otherwise consume the protected content  25 , the media device requires an encrypted key on the protected media  15  which is bound to that particular piece of media. In general, a bound encrypted key is present on protected media comprising authorized protected content, indicating that a user has received as a result of an authorized transaction rights to consume the protected content on that protected media. 
   When the media device  20  accesses the protected content  25  on the protected media  15 , no valid encrypted key for this particular piece of media is found. The media device  20  accesses system  10  on the protected media  15 . System  10  comprises a link such as a URL to a lookup server  30 . The user accesses the lookup server  30  by means of a lookup server interface  35  and system  10 . The media device  20  can access the lookup server  30  through a network  40 . 
   System  10  provides to the lookup server  30  a unique identifier or a description of the protected content  25  comprising, for example, a title, an author, a composer, a producer, a rights owner, etc. The unique identifier could also consist of a cryptographic hash of the encrypted content. The lookup server  30  looks up retailers or other service providers that are authorized to sell a license for use of the protected content  25 . The user selects one of the service providers using the lookup server interface  35  by, for example, selecting a link or URL. 
   The media device  20  can access a service provider  45  (an available source) through the network  40 . The user completes a transaction with the service provider  45  that conveys to the user rights to consume the protected content  25  on the protected media  15 . This transaction may take the form of a purchase, a rental, or a promotional event that allows the user to consume the protected content  25 . The media device  20  can access a security provider  50  through the network  40 . The media device  20  provides to the security provider  50  proof of the transaction with the service provider  45 . In return, the security provider  50  provides to the user an encrypted key for the protected content  25  on the protected media  15 . The encrypted key “binds” the protected content  25  to the protected media  15 , enabling the user to consume the protected content  25  on the protected media  15  within the terms of the transaction with the service provider  45 . 
   The media device  20  comprises software that allows the user to interface securely with the lookup server  30 , the service provider  45 , and the security provider  50 . The media device  20  is connected to network  40  via a communications link  55  such as a telephone, cable, or satellite link. Lookup server  30  can be connected to network  40  via communications link  60 . Service provider  45  can be connected to network  40  via communications link  65 . Security provider  50  can be connected to network  40  via communications link  70 . While system  10  is described in terms of network  40 , the media device  20  may access the lookup server  30 , the service provider  45 , or the security provider  50  locally rather than remotely. 
     FIG. 2  ( FIGS. 2A ,  2 B) illustrates a method  200  of system  10  in licensing protected content obtained through superdistribution. A user receives the protected content  20  (step  205 ) through some unauthorized method of distribution. The user writes the protected content  20  to the protected media  15  (step  210 ). The user attempts to play the protected content  20  on the media device  20  (step  215 ). The media device  20  discovers that the protected media  15  does not comprise a required encrypted key (step  220 ). The media device  20  accesses the protected content distribution system (system  10 ) (step  225 ). System  10  directs the user to the lookup server  30  through the lookup server interface  35  and provides the lookup server  30  with a description of the protected content  25  (step  230 ). 
   The lookup server  30  looks up retailers or other service providers such as service provider  45  authorized to sell, rent, or give away a user license for consumption of the protected content  25  (step  235 ). The lookup server  30  presents a list of found service providers to the user via the lookup server interface  35  (step  240 ). The user selects a service provider such as the service provider  45  by, for example, selecting a link to the service provider  45  (step  245 ). The user purchases, rents, or receives free of charge a license to consume the protected content  25  (step  250 ). The service provider  45  authorizes transmission of an encrypted key to the media device  20  (step  255 ). Authorization comprises providing a proof of purchase to the media device  20 ; the media device  20  provides the proof of purchase to the security provider  50  in exchange for the encrypted key. Alternatively the service provider  45  sends the proof of purchase directly to the security provider  50 ; the security provider  50  then transmits the encrypted key to the media device  20 . 
   The media device  20  records the encrypted key on the protected media  15  (step  260 ). The encrypted key binds the protected content  25  to the protected media  15 , requiring that the protected content  25  only be consumed from the protected media  15 . The media player  20  plays the protected content  25  on the protected media  15  (step  265 ). 
     FIG. 3  illustrates one embodiment of system  10 , a system  10 A (which is generally similar to system  10 ) in which a protected media  15 A is used as a protected media dongle. It should be clear that the dongle model could be implemented independently from any other model described herein, such as the superdistribution model. 
   The protected media  15 A is generally similar to the protected media  15 . Protected media  15 A is further referenced herein as protected media dongle  15 A. Protected content  25 A is stored on a media device  20 A. The protected content  25 A is generally similar to protected content  25 . The media device  20 A is generally similar to the media device  20 . The media device  20 A further comprises an application  305  for executing, playing, or otherwise consuming the protected content  25 A. In this embodiment, the media device  20 A is any device that can store and access protected content  25 A and access information on the protected media dongle  15 A through a dongle media device  310 . An exemplary media device  20 A is a personal computer. 
   System  10 A stores an encrypted key for the protected content  25 A on the protected media dongle  15 A. To execute or otherwise operate the protected content  25 A, the media device  15 A requires access to the encrypted key for the protected content  25 A. Consequently, the protected content  25 A can only be consumed when the protected media dongle  15 A is inserted in the dongle media device  310 . An exemplary protected media dongle  15 A is an SD card. An exemplary protected media dongle device  310  is an SD card reader/writer. The protected media dongle device  310  is any device that can read from and write to the protected media dongle  15 A. 
     FIG. 4  illustrates a method  400  of system  10  in using a protected media dongle  15 A to provide secure and legitimate use of protected content  25 A stored on a media device  20 A. A user acquires the protected content  25 A (step  405 ). In the case of step  405 , acquiring the protected content  25 A comprises obtaining a license to consume the protected content  25 A. This license may be obtained by downloading the protected content  25 A in a transaction with an authorized source such as the service provider  45  for the protected content  25 A. Alternatively, the license may be obtained for unauthorized content as described in  FIG. 2  in step  205  through step  255 . A result of the transaction with the service provider  45  is an encrypted key that enables the media device  15 A to execute or otherwise consume the protected content  25 A. The protected media dongle device  310  records the encrypted key on the protected media dongle  15 A (step  410 ). 
     FIG. 5  illustrates a method  500  of operation by application  305  executing, playing, or otherwise consuming the protected content  25 A protected by an encrypted key stored on the protected media dongle  15 A. A user launches application  305  to execute the protected content  25 A (step  505 ). Application  305  retrieves an encrypted key for the protected content  25 A from system  10  on the protected media dongle  15 A (step  510 ). 
   Application  305  determines whether the protected content  25 A matches the encryption key on the protected media dongle  15 A (decision step  515 ). If the protected content  25 A does not match the encryption key, the application executes method  400  illustrated in  FIG. 4  to obtain an encryption key (step  520 ). Otherwise, the application  305  enforces usage conditions for the protected content  25 A as managed by system  10  on the protected media dongle  15 A (step  525 ). Usage conditions comprise, for example, a number of times the protected content  15 A can be executed. Application  305  uses the encryption key to decrypt the protected content  15 A on the media device  20 A (step  530 ) and executes or otherwise consumes the protected content  25 A (step  535 ). 
     FIG. 6  illustrates another embodiment of system  10 , a system  10 B (which is generally similar to system  10  or  10 A) in which a protected media  15 B is used as an electronic wallet. The protected media  15 B is generally similar to the protected media  15 . Protected media  15 B is further referenced herein as a protected media electronic wallet  15 B. Protected content  25 B is stored on a protected media electronic wallet  15 B. The protected content  25 B is generally similar to the protected content  25 . The protected content  25 B comprises a budget or a state that can be used by a user to purchase, rent, or otherwise obtain products such as, for example, copyrighted content. The protected media electronic wallet  15 B comprises system  10 B for maintaining the state or the budget of the protected media electronic wallet  15 B. 
   With further reference to  FIG. 6 ,  FIG. 7  ( FIGS. 7A ,  7 B) illustrates a method  700  of system  10 B on the protected media electronic wallet  15 B. A user performs a transaction to obtain a protected media electronic wallet  15 B preloaded with a predetermined budget (step  705 ). The transaction may comprise purchase, subscription, rental, or promotional give-away. Alternatively, the user may select an initial budget or state for the protected media electronic wallet  15 B at, for example, a kiosk in a retail store; a security provider in the kiosk burns the selected initial budget or state on the protected media electronic wallet  15 B. 
   The user inserts the protected media electronic wallet  15 B into a media device  20 B (step  710 ). The media device  20 B is generally similar to the media device  20 . The media device  20 B may be located, for example, in the retail store, at the home of the user, or some other location where the media device  20 B has access to a service provider such as the service provider  45  and a security provider such as the security provider  50 . The user accesses the service provider  50  as directed by system  10  on the protected media electronic wallet  15 B (step  715 ) using, for example, a electronic wallet interface  605 . The user selects a protected content product such as an application, an audio file, a video file, a movie, an electronic book, a database, etc. from products offered by the service provider  50  (step  720 ). 
   The service provider  45  determines whether sufficient value remains in the budget or state of the protected media electronic wallet  15 B to complete the selected transaction (decision step  725 ). If no, the service provider  45  refuses the transaction (step  730 ). If yes, the security provider  50  authorizes the transaction (step  735 ). The security provider issues an encryption key update to the media device reflecting a new balance on the protected media electronic wallet  15 B that reflects a value of the transaction (step  740 ). 
   The user downloads to the protected media electronic wallet  15 B the protected content  25 B as an encrypted file (step  745 ). The media device records new encrypted information reflecting a decremented value for the budget or state of the protected media electronic wallet  15 B that reflects the transaction (step  750 ). The protected media electronic wallet  15 B comprises the budget or state of the protected media electronic wallet  15 B and the downloaded protected content  25 B. The user may download additional downloaded protected content  25 B until the budget or state of the protected media electronic wallet  15 B is exhausted. The user may add to the value of the budget or state of the protected media electronic wallet  15 B by performing a transaction with the service provider  45  and the security provider  50  using, for example, the electronic wallet interface  605 . It should be clear that the downloaded protected content  25 B may occur to a hard drive or to a different protected media, and that the wallet (i.e., budget data) and the actual content might not necessarily be combined on the same protected media. 
   Alternatively, the user may have already obtained the protected content  25 B through other sources such as, for example, through superdistribution, and written the protected content to the protected media electronic wallet  15 B. In this case, the user is obtaining an encrypted key for playing the protected content  25 B, in a manner similar to the process described previously for  FIGS. 1 and 2 . 
   For example, the service provider  45  offers to customers an ability to purchase protected content using the protected media electronic wallet  15 B. A user purchases the protected media electronic wallet  15 B preloaded with 60 credits; the protected media electronic wallet  15 B has a capacity of fifty songs. The protected media electronic wallet  15 B comprises a media ID of 139. The service provider  45  sells a recently released song for six credits while other songs cost three credits. An exemplary list of songs from which the user may select for purchase is shown in Table 1. 
   
     
       
             
           
             
             
             
           
         
             
               TABLE 1 
             
           
           
             
                 
             
             
               An exemplary list of songs for rental using the protected media 
             
             
               electronic wallet 15B. 
             
           
        
         
             
               Movie ID 
               Music Title 
               Credit Cost 
             
             
                 
             
             
               1 
               Song A 
               6 
             
             
               2 
               Song B 
               3 
             
             
               3 
               Song C 
               3 
             
             
                 
             
           
        
       
     
   
   Table 2 illustrates a history of use for the protected media electronic wallet  15 B by the user after purchase of three songs. The budget balance of the protected media electronic wallet  15 B is decremented each time the user purchase a song according to the price of the song. The resulting balance is encrypted in the encryption key and written to the protected media electronic wallet  15 B each time a song is purchased. 
   
     
       
             
           
             
             
             
           
         
             
               TABLE 2 
             
           
           
             
                 
             
             
               An exemplary history of song purchase using the protected media 
             
             
               electronic wallet 15B. 
             
           
        
         
             
               Previous Balance 
               New Balance 
               Song ID 
             
             
                 
             
             
               60 
               54 
               1 
             
             
               54 
               51 
               3 
             
             
               51 
               48 
               2 
             
             
                 
             
           
        
       
     
   
     FIG. 8  illustrates a further embodiment of system  10 , a system  10 C (which is generally similar to system  10 ) in which a protected media  15 C is used as rental container. The protected media  15 C is generally similar to the protected media  15 . The protected media  15 C is further referenced herein as a protected media rental container  15 C. Protected content  25 C is stored on the protected media rental container  15 C. The protected content  25 C is generally similar to the protected content  25 . The protected media rental container  15 C comprises a budget or a state that can be used to rent copyrighted content. The protected media rental container  15 C further comprises system  10 C for maintaining the state or the budget of the protected media rental container  15 C. 
   With further reference to  FIG. 8 ,  FIG. 9  ( FIGS. 9A ,  9 B) illustrates a method  900  of system  10 C on the protected media rental container  15 C. A user subscribes to a protected content rental service and receives the protected media rental container  15 C (step  905 ). The user inserts the protected media rental container  15 C into a media device  20 C (step  910 ). The media device  20 C is generally similar to the media device  20 . In a preferred embodiment, all that is needed to manage the particular rental offering is the media ID. 
   The user selects the rental content for download (step  915 ). The rental service may provide additional copies of the protected media rental container  15 C to the user for an additional fee, as a part of the basic subscription, as a promotional give away, etc. An exemplary media table is illustrated in Table 4 listing exemplary media IDs for the copies of the protected media rental container  15 C. 
   
     
       
             
           
         
             
               TABLE 4 
             
             
                 
             
             
               Exemplary media table listing media IDs. 
             
             
               Media ID 
             
             
                 
             
           
           
             
               123 
             
             
               456 
             
             
                 
             
           
        
       
     
   
   The service provider  45  of the rental service determines if the media ID is authorized to rent the protected content  25 C on the protected media rental container  15 C currently inserted in the media device  20 C (decision step  920 ). If the media ID is not authorized, the service provider  45  offers to add additional media to the subscription (decision step  925 ). If the user declines this offers, the service provider  45  refuses the transaction (step  930 ). If the user accepts the offer, the user enters a transaction with the service provider  45  and upgrades the media subscription to include the protected media rental container  15 C currently inserted in the media device (step  935 ). 
   The user selects a product for rental (step  940 ). In addition, if the media ID is authorized (step  920 ), the user will be authorized to select the desired product for rental. 
   The product comprises, for example, copyrighted content such as a movie, an audio file, a video file, an electronic book, a database, a game, an application, etc. For example, the rental service may rent movies to a user that subscribes to the rental service. An exemplary list of movies available for rental is shown in Table 5. 
   
     
       
             
           
             
             
             
           
         
             
               TABLE 5 
             
           
           
             
                 
             
             
               Exemplary movie table listing a movie ID for each of the movies 
             
             
               available for rental from the rental service. 
             
           
        
         
             
                 
               Movie ID 
               Movie Title 
             
             
                 
                 
             
             
                 
               1 
               Movie A 
             
             
                 
               2 
               Movie B 
             
             
                 
               3 
               Movie C 
             
             
                 
               4 
               Movie D 
             
             
                 
                 
             
           
        
       
     
   
   The user selects, for example, Movie C. The service provider  45  determines whether the subscription of the user allows rental of the selected product (decision step  945 ). For example, a subscription may allow a user to rent three movies at any one time. The protected media rental container  15 C comprises three movies currently rented by the user. In this case, the user can upgrade his subscription to rent more movies on the protected media rental container  15 C, select a movie on the protected media rental container  15 C for overwriting by the newly selected movie, or cancel the transaction. 
   If the protected media rental container  15 C comprises fewer than the maximum allowed number of products that may be rented at any one time, the subscription allows the selected product (decision step  945 ). The service provider  45  allows the media device  20 C to download to the protected media rental container  15 C the selected product and an encryption key prepared by the security provider  50 . The encryption key comprises a media ID for each of the items of protected content allowed for consumption by the user on the protected media rental container  15 C. 
   An exemplary table of movies and associated media ID rented by user ID “psuedo” is shown in Table 6. The user selects Movie D for downloading to the protected media rental container  15 C with media ID 123. The subscription of the user allows rental of two movies at any one time on the protected media rental container  15 C with media ID 123. The subscription does not allow the user to simply add Movie D to the protected media rental container  15 C with media ID 123 (decision step  945 ). 
   
     
       
             
           
             
             
             
             
             
           
         
             
               TABLE 6 
             
           
           
             
                 
             
             
               An exemplary list of movies and associated media ID rented by the 
             
             
               user “pseudo” as of a specific date such as, for example, August 22. 
             
           
        
         
             
                 
               User ID 
               Media ID 
               Movie ID 
               Download Date 
             
             
                 
                 
             
             
                 
               psuedo 
               123 
               1 
               August 15 
             
             
                 
               psuedo 
               456 
               3 
               August 15 
             
             
                 
               psuedo 
               123 
               2 
               August 22 
             
             
                 
                 
             
           
        
       
     
   
   The service provider  45  asks the user whether the user wishes to upgrade the subscription (decision step  955 ). If yes, the user enters a transaction with the service provider  45  and upgrades the subscription to allow the selected product (step  960 ) and processing proceeds to step  950 . If the user does not wish to upgrade the subscription (decision step  955 ), the service provider  45  asks the user whether the user wishes to overwrite a movie on the protected media rental container  15 C with media ID 123 with the new movie (decision step  965 ). If yes, the user selects a movie such as, for example, Movie A (Movie ID 1) for overwriting by the new movie (Movie D with movie ID 4) (step  970 ) and processing proceeds to step  945 ). If the user declines to select a movie for overwriting, the service provider  45  refuses the rental transaction (step  975 ). 
   It is to be understood that the specific embodiments of the invention that have been described are merely illustrative of certain applications of the principle of the present invention. Numerous modifications may be made to the system, service, and method for distributing protected content using protected media described herein without departing from the spirit and scope of the present invention. Moreover, while the present system is described in terms of CPRM, it should be clear that the present system may be applied to, for example, any copy protection system utilizing broadcast encryption. Further, while the present invention is described for illustration purpose only in relation to the WWW, it should be clear that the invention is applicable as well to, for example, to any network over which content may be distributed.