Digital content preparation system6959288Abstract A digital content preparation system that includes a metadata acquisition tool for acquiring metadata associated with the digital content, and a digital content processor for processing the digital content by performing at least one of watermarking, encoding, and encrypting. A work flow manager manages processings by the metadata acquisition tool and the digital content processor. In one preferred embodiment, the metadata acquisition tool includes an automatic metadata acquisition tool and a manual metadata acquisition tool, and the digital content processor includes an encoder and an encrypter. The present invention also provides a method for preparing digital content. According to the method, metadata associated with the digital content is acquired, and the digital content is processed by at least one of watermarking, encoding, and encrypting. Processings in the acquiring step and the processing step are managed. In a preferred method, the acquiring step includes automatically retrieving at least a portion of the metadata and allowing manual entry of at least a portion of the metadata, and the processing step includes encoding the digital content and encrypting the encoded digital content. Claims 1. A digital content preparation system comprising: Description BACKGROUND OF THE INVENTION
The Secure Digital Content Electronic Distribution System is a technical platform that encompasses the technology, specifications, tools, and software needed for the secure delivery and rights management of Digital Content and digital content-related content to an end-user, client device. The End-User Device(s) include PCS, set top boxes (IRDs), and Internet appliances. These devices may copy the content to external media or portable, consumer devices as permitted by the content proprietors. The term Digital Content or simply Content, refers to information and data stored in a digital format including: pictures, movies, videos, music, programs, multimedia and games. The technical platform specifies how Digital Content is prepared, securely distributed through point-to-point and broadcast infrastructures (such as cable, Internet, satellite, and wireless) licensed to End-User Device(s), and protected against unauthorized copying or playing. In addition, the architecture of the technical platform allows for the integration and migration of various technologies such as watermarking, compression/encoding, encryption, and other security algorithms as they evolve over time. The base components of the Secure Digital Content Electronic Distribution System are: (1) rights management for the protection of ownership rights of the content proprietor; (2) transaction metering for immediate and accurate compensation; and (3) an open and well-documented architecture that enables Content Provider(s) to prepare content and permit its secure delivery over multiple network infrastructures for playback on any standard compliant player. 1. Rights Management Rights management in the Secure Digital Content Electronic Distribution System is implemented through a set of functions distributed among the operating components of the system. Its primary functions include: licensing authorization and control so that content is unlocked only by authorized intermediate or End-User(s) that have secured a license; and control and enforcement of content usage according to the conditions of purchase or license, such as permitted number of copies, number of plays, and the time interval or term the license may be valid. A secondary function of rights management is to enable a means to identify the origin of unauthorized copies of content to combat piracy. Licensing authorization and control are implemented through the use of a Clearinghouse(s) entity and Secure Container (SC) technology. The Clearinghouse(s) provides licensing authorization by enabling intermediate or End-User(s) to unlock content after verification of a successful completion of a licensing transaction. Secure Containers are used to distribute encrypted content and information among the system components. A SC is a cryptographic carrier of information or content that uses encryption, digital signatures, and digital certificates to provide protection against unauthorized interception or modification of electronic information and content. It also allows for the verification of the authenticity and integrity of the Digital Content. The advantage of these rights management functions is that the electronic Digital Content distribution infrastructure does not have to be secure or trusted. Therefore allowing transmission over network infrastructures such as the Web and Internet. This is due to the fact that the Content is encrypted within Secure Containers and its storage and distribution are separate from the control of its unlocking and use. Only users who have decryption keys can unlock the encrypted Content, and the Clearinghouse(s) releases decryption keys only for authorized and appropriate usage requests. The Clearinghouse(s) will not clear bogus requests from unknown or unauthorized parties or requests that do not comply with the content's usage conditions as set by the content proprietors. In addition, if the SC is tampered with during its transmission, the software in the Clearinghouse(s) determines that the Content in a SC is corrupted or falsified and repudiate the transaction. The control of Content usage is enabled through the End-User Player Application 195 running on an End-User Device(s). The application embeds a digital code in every copy of the Content that defines the allowable number of secondary copies and play backs. Digital watermarking technology is used to generate the digital code, to keep it hidden from other End-User Player Application 195, and to make it resistant to alteration attempts. In an alternate embodiment, the digital code is just kept as part of the usage conditions associated with the Content 113. When the Digital Content 113 is accessed in a compliant End-User Device(s), the End-User Player Application 195 reads the watermark to check the use restrictions and updates the watermark as required. If the requested use of the content does not comply with the usage conditions, e.g., the number of copies has been exhausted, the End-User Device(s) will not perform the request. Digital watermarking also provides the means to identify the origin of authorized or unauthorized copies of Content. An initial watermark in the Content is embedded by the content proprietor to identify the content proprietor, specify copyright information, define geographic distribution areas, and add other pertinent information. A second watermark is embedded in the Content at the End-User Device(s) to identify the content purchaser (or licensee) and End-User Device(s), specify the purchase or license conditions and date, and add any other pertinent information. Since watermarks become an integral part of the Content, they are carried in the copies independent of whether the copies were authorized or not. Thus the Digital Content always contains information regarding its source and its permitted use regardless of where the content resides or where it comes from. This information may be used to combat illegal use of the Content. 2. Metering As part of its rights management functions, the Clearinghouse(s) keeps a record of all transactions where a key exchange is cleared through the Clearinghouse(s). This record allows for the metering of licensing authorization and the original conditions of use. The transaction record can be reported to responsible parties, such as, content proprietors or Content Provider(s), retailers, and others, on an immediate or periodic basis to facilitate electronic reconciliation of transaction payments and other uses. 3. Open Architecture The Secure Digital Content Electronic Distribution System (System) is an open architecture with published specifications and interfaces to facilitate broad implementation and acceptance of the System in the market place while maintaining rights protection for the content proprietors. The flexibility and openness of the System architecture also enable the System to evolve over time as various technologies, transmission infrastructures, and devices are delivered to the marketplace. The architecture is open regarding the nature of the Content and its format. Distribution of audio, programs, multimedia, video, or other types of Content is supported by the architecture. The Content could be in a native format, such as linear PCM for digital music, or a format achieved by additional preprocessing or encoding, such as filtering, compression, or pre/de-emphasis, and more. The architecture is open to various encryption and watermarking techniques. It allows for the selection of specific techniques to accommodate different Content types and formats and to allow the introduction or adoption of new technologies as they evolve. This flexibility allows Content Provider(s) to pick and evolve the technologies they use for data compression, encryption, and formatting within the Secure Digital Content Electronic Distribution System. The architecture is also open to different distribution networks and distribution models. The architecture supports content distribution over low-speed Internet connections or high-speed satellite and cable networks and can be used with point-to-point or broadcast models. In addition, the architecture is designed so that the functions in the End-User Device(s) can be implemented on a wide variety of devices, including low cost consumer devices. This flexibility allows Content Provider(s) and retailers to offer Content to intermediate or End-User(s) through a variety of service offerings and enables the users to purchase or license Content, play it back, and record it on various compliant player devices. B. System Functional Elements Turning now to FIG. 1, there is shown a block diagram illustrating an overview of a Secure Digital Content Electronic Distribution System 100 according to the present invention. The Secure Digital Content Electronic Distribution System 100 encompasses several business elements that comprise an end-to-end solution, including: Content Provider(s) 101 or the proprietors of the Digital Content,Electronic Digital Content Store(s) 103, Intermediate Market Partners (not shown), Clearinghouse(s) 105, Content Hosting Site 111, Transmission Infrastructures 107, and End-User Device(s) 109. Each of these business elements use various components of the Secure Digital Content Electronic Distribution System 100. A high level description of these business elements and system components, as they pertain specifically to electronic Content 113 distribution, follows. 1. Content Provider(s) 101 Content Provider(s) 101 or content proprietor(s) are owners of original Content 113 and/or distributors authorized to package independent Content 113 for further distribution. Content Provider(s) 101 may exploit their rights directly or license Content 113 to the Electronic Digital Content Store(s) 103, or Intermediate Market Partners (not shown), usually in return for Content usage payments related to electronic commerce revenues. Examples of Content Provider(s) 101 include Sony, Time-Warner, MTV, IBM, Microsoft, Turner, Fox and others. Content Provider(s) 101 use tools provided as part of the Secure Digital Content Electronic Distribution System 100 in order to prepare their Content 113 and related data for distribution. A Work Flow Manager Tool 154 schedules Content 113 to be processed and tracks the Content 113 as it flows through the various steps of Content 113 preparation and packaging to maintain high quality assurance. The term metadata is used throughout this document to mean data related to the Content 113 and in this embodiment does not include the Content 113 itself. As an example, metadata for a song may be a song title or song credits but not the sound recording of the song. The Content 113 would contain the sound recording. A Metadata Assimilation and. Entry Tool 161 is used to extract metadata from the Content Provider(s)' Database 160 or data provided by the Content Provider(s) in a prescribed format (for a music example the Content 113 information such as CD title, artist name, song title, CD artwork,. and more) and to package it for electronic distribution. The Metadata Assimilation and Entry Tool 161 is also used to enter the Usage Conditions for the Content 113. The data in Usage Conditions can include copy restriction rules, the wholesale price, and any business rules deemed necessary. A Watermarking Tool is used to hide data in the Content 113 that identifies the content owner, the processing date, and other relevant data. For an embodiment where the Content 113 is audio, an audio preprocessor tool is used to adjust the dynamics and/or equalize the Content 113 or other audio for optimum compression quality, compress the Content 113 to the desired compression levels, and encrypt the Content 113. These can be adapted to follow technical advances in digital content compression/encoding, encryption, and formatting methods, allowing the Content Provider(s) 101 to utilize best tools as they evolve over time in the marketplace. The encrypted Content 113, digital content-related data or metadata, and encrypted keys are packed in SCs (described below) by the SC Packer Tool and stored in a content hosting site and/or promotional web site for electronic distribution. The content hosting site can reside at the Content Provider(s) 101 or in multiple locations, including Electronic Digital Content Store(s) 103 and Intermediate Market Partners (not shown) facilities. Since both the Content 113 and the Keys (described below) are encrypted and packed in SCs, Electronic Digital Content Store(s) 103 or any other hosting agent can not directly access decrypted Content 113 without clearance from the Clearinghouse(s) and notification to the Content Provider(s) 101. 2. Electronic Digital Content Store(s) 103 Electronic Digital Content Store(s) 103 are the entities who market the Content 113 through a wide variety of services or applications, such as Content 13 theme programming or electronic merchandising of Content 113. Electronic Digital Content Store(s) 103 manage the design, development, business operations, settlements, merchandising, marketing, and sales of their services. Example online Electronic Digital Content Store(s) 103 are Web sites that provide electronic downloads of software. Within their services, Electronic Digital Content Store(s) 103 implement certain functions of the Secure Digital Content Electronic Distribution System 100. Electronic Digital Content Store(s) 103 aggregate information from the Content Provider(s) 101, pack content and metadata in additional SCs, and deliver those SCs to consumers or businesses as part of a service or application. Electronic Digital Content Store(s) 103 use tools provided by the Secure Digital Content Electronic Distribution System 100 to assist with: metadata extraction, secondary usage conditions, SC packaging, and tracking of electronic content transactions. The secondary usage conditions data can include retail business offers such as Content 113 purchase price, pay-per-listen price, copy authorization and target device types, or timed-availability restrictions. Once an Electronic Digital Content Store(s) 103 completes a valid request for electronic Content 113 from an End-User(s), the Electronic Digital Content Store(s) 103 is responsible for authorizing the Clearinghouse(s) 105 to release the decryption key for the Content 113 to the customer. The Electronic Digital Content Store(s) also authorizes the download of the SC containing the Content 113. The Electronic Digital Content Store(s) may elect to host the SCs containing the Digital Content at its local site and/or utilize the hosting and distribution facilities of another Content hosting site. The Electronic Digital Content Store(s) can provide customer service for any questions or problems that an End-User(s) may have using the Secure Digital Content Electronic Distribution System 100, or the Electronic Digital Content Store(s) 103 may contract their customer service support to the Clearinghouse(s) 105. 3. Intermediate Market Partners (not shown) In an alternate embodiment, the Secure Digital Content Electronic Distribution System 100 can be used to provide Content I 13 securely to other businesses called Intermediate Market Partners. These partners may include digital content-related companies offering a non-electronic service, such as televisions stations or video clubs, radio stations or record clubs, that distribute Content 113. These Partners may also include other trusted parties who handle material as part of making or marketing sound recordings, such as record studios, replicators, and producers. These Intermediate Market Partners requires clearance from the Clearinghouse(s) 105 in order to decrypt the Content 113. 4. Clearinghouse(s) 105 The Clearinghouse(s) 105 provides the licensing authorization and record keeping for all transactions that relate to the sale and/or permitted use of the Content 113 encrypted in a SC. When the Clearinghouse(s) 105 receives a request for a decryption key for the Content 113 from an intermediate or End-User(s), the Clearinghouse(s) 105 validates the integrity and authenticity of the information in the request; verifies that the request was authorized by an Electronic Digital Content Store(s) or Content Provider(s) 101; and verifies that the requested usage complies with the content Usage Conditions as defined by the Content Provider(s) 101. Once these verifications are satisfied, the Clearinghouse(s) 105 sends the decryption key for the Content 113 to the requesting End-User(s) packed in a License SC. The key is encrypted in a manner so that only the authorized user can retrieve it. If the End-User's request is not verifiable, complete, or authorized, the Clearinghouse(s) 105 repudiates the request for the decryption key. The Clearinghouse(s) 105 keeps a record of all transactions and can report them to responsible parties, such as Electronic Digital Content Store(s) 103 and Content Provider(s) 101, on an immediate, periodic, or restricted basis. This reporting is a means by which Content Provider(s) 101 can be informed of the sale of Content 113 and the Electronic Digital Content Store(s) 103 can obtain an audit trail of electronic delivery to their customers. The Clearinghouse(s) 105 can also notify the Content Provider(s) 101 and/or Electronic Digital Content Store(s) 103 if it detects that information in a SC has been compromised or does not comply with the Content's Usage Conditions. The transaction recording and repository capabilities of the Clearinghouse(s) 105 database is structured for data mining and report generation. In another embodiment, the Clearinghouse(s) 105 can provide customer support and exception processing for transactions such as refunds, transmission failures, and purchase disputes. The Clearinghouse(s) 105 can be operated as an independent entity, providing a trusted custodian for rights management and metering. It provides billing and settlement as required. Examples of electronic Clearinghouse(s) include Secure-Bank.com and Secure Electronic Transaction (SET) from Visa/Mastercard. In one embodiment, the Clearinghouse(s) 105 are Web sites accessible to the End-User Device(s) 109. In another embodiment, the Clearinghouse(s) 105 is part of the Electronic Digital Content Store(s) 103. 5. End-User Device(s) 109 The End-User Device(s) 109 can be any player device that contains an End-User Player Application 195 (described later) compliant with the Secure Digital Content Electronic Distribution System 100 specifications. These devices may include PCS, set top boxes (IRDs), and Internet appliances. The End-User Player Application 195 could be implemented in software and/or consumer electronics hardware. In addition to performing play, record, and library management functions, the End-User Player Application 195 performs SC processing to enable rights management in the End-User Device(s) 109. The End-User Device(s) 109 manages the download and storage of the SCs containing the Digital Content; requests and manages receipt of the encrypted Digital Content keys from the Clearinghouse(s) 105; processes the watermark(s) every time the Digital Content is copied or played; manages the number of copies made (or deletion of the copy) in accordance with the Digital Content's Usage Conditions; and performs the copy to an external media or portable consumer device if permitted. The portable consumer device can perform a subset of the End-User Player Application 195 functions in order to process the content's Usage Conditions embedded in the watermark. The terms End-User(s) and End-User Player Application 195 are used throughout this to mean through the use or running-on an End-User Device(s) 109. 6. Transmission Infrastructures 107 The Secure Digital Content Electronic Distribution System 100 is independent of the transmission network connecting the Electronic Digital Content Store(s) 103 and End-User Device(s) 109. It supports both point-to-point such as the Internet and broadcast distribution models such as digital broadcast television. Even though the same tools and applications are used to acquire, package, and track Content 113 transactions over various Transmission Infrastructures 107, the presentation and method in which services are delivered to the customer may vary depending on the infrastructure and distribution model selected. The quality of the Content 113 being transferred may also vary since high bandwidth infrastructures can deliver high-quality digital content at more acceptable response times than lower bandwidth infrastructures. A service application designed for a point-to-point distribution model can be adapted to support a broadcast distribution model as well. C. System Uses The Secure Digital Content Electronic Distribution System 100 enables the secure delivery of high-quality, electronic copies of Content 113 to End-User Device(s) 109, whether consumer or business, and to regulate and track usage of the Content 113. The Secure Digital Content Electronic Distribution System 100 could be deployed in a variety of consumer and business-to-business services using both new and existing distribution channels. Each particular service could use a different financial model that can be enforced through the rights management features of the Secure Digital Content Electronic Distribution System 100. Models such as wholesale or retail purchase, pay-per-listen usage, subscription services, copy/no-copy restrictions, or redistribution could be implemented through the rights management of the Clearinghouse(s) 105 and the End-User Player Application 195 copy protection features. The Secure Digital Content Electronic Distribution System 100 allows Electronic Digital Content Store(s) 103 and Intermediate Market Partners a great deal of flexibility in creating services that sell Content 113. At the same time it provides Content Provider(s) 101 a level of assurance that their digital assets are protected and metered so that they can receive appropriate compensation for the licensing of Content 113. II. Cryptography Concepts and their Application to the Secure Digital Content Electronic Distribution System License Control in the Secure Digital Content Electronic Distribution System 100 is based on the use of cryptography. This section introduces basic cryptography technologies of the present invention. The use of public key encryption, symmetric key encryption, digital signatures, digital watermarks and digital certificates is known. Symmetric Algorithms In the Secure Digital Content Electronic Distribution System 100 the Content Provider(s) 101 encrypts the content using symmetric algorithms. They are called symmetric algorithms because the same key is used to encrypt and decrypt data. The data sender and the message recipient must share the key. The shared key is referred to here as the symmetric key. The Secure Digital Content Electronic Distribution System 100 architecture is independent of the specific symmetric algorithm selected for a particular implementation. Common symmetric algorithms are DES, RC2 and RC4. Both DES and RC2 are block cipher. A block cipher encrypts the data using a block of data bits at a time. DES is an official US government encryption standard, has a 64-bit block size, and uses a 56-bit key. Triple-DES is commonly used to increase the security achieved with simple DES. RSA Data Security designed RC2. RC2 uses a variable-key-size cipher and has a block size of 64 bits. RC4 , also designed by RSA Data Security, is a variable-key-size stream cipher. A stream cipher operates on a single data bit at a time. RSA Data Security claims that eight to sixteen machine operations are required for RC4 per output byte. IBM designed a fast algorithm called SEAL. SEAL is a stream algorithm that uses a variable-length key and that has been optimized for 32-bit processors. SEAL requires about five elementary machine instructions per data byte. A 50 MHZ, 486-based computer runs the SEAL code at 7.2 megabytes/second if the 160-bit key used has already been preprocessed into internal tables. Microsoft reports results of encryption performance benchmark in its Overview of CryptoAPI document. These results were obtained by an application using Microsoft's CryptoAPI, running on a 120-MHZ, Pentium-based computer with Windows NT 4.0.
B. Public Key Algorithms In the Secure Digital Content Electronic Distribution System 100, symmetric keys and other small data pieces are encrypted using public keys. Public key algorithms use two keys. The two keys are -mathematically related so that data encrypted with one key can only be decrypted with the other key. The owner of the keys keeps one key private (private key) and publicly distributes the second key (public key). To secure the transmission of a confidential message using a public key algorithm, one must use the recipient's public key to encrypt the message. Only the recipient, who has the associated private key, can decrypt the message. Public key algorithms are also used to generate digital signatures. The private key is used for that purpose. The following section provides information on digital signatures. The most common used public-key algorithm is the RSA public-key cipher. It has become the de-facto public key standard in the industry. Other algorithms that also work well for encryption and digital signatures are ElGamal and Rabin. RSA is a variable-key length cipher. Symmetric key algorithms are much faster than the public key algorithms. In software, DES is generally at least 100 times as fast as RSA. Because of this, RSA is not used to encrypt bulk data. RSA Data Security reports that on a 90 MHZ Pentium machine, RSA Data Security's toolkit BSAFE 3.0 has a throughput for private-key operations (encryption or decryption, using the private key) of 21.6 kilobits/second with a 512-bit modulus and 7.4 kilobits/second with a 1024-bit modulus. C. Digital Signature In the Secure Digital Content Electronic Distribution System 100, the issuer of SC(s) protects the integrity of SC(s) by digitally signing it. In general, to create a digital signature of a message, a message owner first computes the message digest (defined below) and then encrypt the message digest using the owner's private key. The message is distributed with its signature. Any recipient of the message can verify the digital signature first by decrypting the signature using the public key of the message owner to recover the message digest. Then, the recipient computes the digest of the received message and compares it with the recovered one. If the message has not being altered during distribution, the calculated digest and recovered digest must be equal. In the Secure Digital Content Electronic Distribution System 100, since SC(s) contain several data parts, a digest is calculated for each part and a summary digest is calculated for the concatenated part digests. The summary digest is encrypted using the private key of the issuer of the SC(s). The encrypted summary digest is the issuer's digital signature for the SC(s). The part digests and the digital signature are included in the body of the SC(s). The recipients of SC(s) can verify the integrity of the SC(s) and its parts by means of the received digital signature and part digests. A one-way hash algorithm is used to calculate a message digest. A hash algorithm takes a variable-length-input message and converts it into a fixed length string, the message digest. A one-way hash algorithm operates only in one direction. That is, it is easy to calculate the digest for an input message, but it is very difficult (computationally infeasible) to generate the input message from its digest. Because of the properties of the one-way hash functions, one can think of a message digest as a fingerprint of the message. The more common one-way hash functions are MD5 from RSA Data Security and SHA designed by the U.S. National Institute of Technology and Standards (NITS). D. Digital Certificates A digital certificate is used to authenticate or verify the identity of a person or entity that has sent a digitally signed message. A certificate is a digital document issued by a certification authority that binds a public key to a person or entity. The certificate includes the public key, the name of the person or entity, an expiration date, the name of the certification authority, and other information. The certificate also contains the digital signature of the certification authority. When an entity (or person) sends a message signed with its private key and accompanied with its digital certificate, the recipient of the message uses the entity's name from the certificate to decide whether or not to accept the message. In the Secure Digital Content Electronic Distribution System 100, every SC(s), except those issued by the End-User Device(s) 109, includes the certificate of the creator of the SC(s). The End-User Device(s) 109 do not need to include certificates in their SC(s) because many End-User(s) do not bother to acquire a certificate or have certificates issued by non bona-fide Certification Authorities. In the Secure Digital Content Electronic Distribution System 100, the Clearinghouse(s) 105 has the option of issuing certificates to the Electronic Digital Content Store(s) 103. This allows the End-User Device(s) 109 to independently verify that the Electronic Digital Content Store(s) 103 have been authorized by the Secure Digital Content Electronic Distribution System 100. E. Guide To The SC(s) Graphical Representation This document uses a drawing to graphically represent SC(s) that shows encrypted parts, non-encrypted parts, the encryption keys, and certificates. Referring now to FIG. 2 is an example drawing of SC(s) 200. The following symbols are used in the SC(s) figures. Key 201 is a public or private key. The teeth of the key e.g. CLRNGH for Clearinghouse indicate the key owner. PB inside the handle indicates that it is a public key thus key 201 is a Clearinghouse public key. PV inside the handle indicates that it is a private key. Diamond shape is an End-User Digital Signature 202. The initials indicate which private key was used to create the signature thus in EU is the End-User(s) digital signature from table below. Symmetric key 203 is used to encrypt content. An encrypted symmetric key object 204 comprising a symmetric key 203 encrypted with a PB of CLRNGH. The key on the top border of the rectangle is the key used in the encryption of the object. The symbol or text inside the rectangle indicates the encrypted object (a symmetric key in this case). Another encrypted object, in this example a Transaction ID encrypted object 205 is shown. And Usage Conditions 206 for content licensing management as described below. The SC(s) 200 comprises Usage Conditions 206, Transaction ID encrypted object 205, an Application ID encrypted object 207, and encrypted symmetric key object 204, all signed with an End-User Digital Signature 202. The table below shows the initials that identify the signer of SC(s).
F. Example of a Secure Container Encryption The tables and diagrams below provide an overview of the encryption and decryption process used to create and recover information from SC(s). The SC(s) that is created and decrypted in this process overview is a general SC(s). It does not represent any of the specific SC(s) types used for rights management in the Secure Digital Content Electronic Distribution System 100. The process consists of the steps described in FIG. 3 for encryption process. Process Flow for Encryption Process of FIG. 3 Process Flow for Decryption Process of FIG. 4 III. Secure Digital Content Electronic Distribution System Flow The Secure Electronic Digital Content Distribution System 100, consists of several components that are used by the different participants of the system. These participants include the Content Provider(s) 101, Electronic Digital Content Store(s) 103, End-User(s) via End-User Device(s) 109 and the Clearinghouse(s) 105. A high level system flow is used as an overview of the Secure Digital Content Electronic Distribution System 100. This flow outlined below tracks Content as it flows throughout the System 100. Additionally it outlines the steps used by the participants to conduct the transactions for the purchase, unlocking and use of the Content 113. Some of the assumptions made in the system flow include:
It should be understood by those skilled in the art that these assumptions can be altered to accommodate the exact nature of the Digital Content e.g. music, video and program and electronic distribution systems broadcast. The following process flow in illustrated in FIG. 1.
Rights Management Architecture Model Architecture Layer Functions FIG. 5 is a block diagram of the Rights Management Architecture of the Secure Digital Electronic Distribution System 100. Architecturally, four layers represent the Secure Digital Content Electronic Distribution System 100: the License Control Layer 501, the Content Identification Layer 503, Content Usage Control Layer 505, and the Content Formatting Layer 507. The overall functional objective of each layer and the individual key functions for each layer are described in this section. The functions in each of the layers are fairly independent of the functions in the other layers. Within broad limitations, Frictions in a layer can be substituted with similar functions without affecting the functionality of the other layers. Obviously, it is required that the output from one layer satisfies format and semantics acceptable to the adjacent layer. The License Control Layer 501 ensures that:
The Content Identification Layer 503 allows for the verification of the copyright and the identity of the content purchaser. The content's copyright information and identity of the content purchaser enables the source tracking of any, authorized or not, copy of the Content 113. Thus, the Content Identification Layer 503 provides a means to combat piracy. The Content Usage Control Layer 505 ensures that the copy of the Content 113 is used in the purchaser's device according to the Store Usage Conditions 519. The Store Usage Conditions 519 may specify the number of plays and local copies allowed for the Content 113, and whether or not the Content 113 may be recorded to an external portable device. The functions in the Content Usage Control Layer 505 keep track of the content's copy/play usage and update the copy/play status. The Content Formatting Layer 507 allows for the format conversion of the Content 113 from its native representation in the content owner's facilities into a form that is consistent with the service features and distribution means of the Secure Digital Content Electronic Distribution System 100. The conversion processing may include compression encoding and its associated preprocessing, such as frequency equalization and amplitude dynamic adjustment. For Content 113 which is audio, at the purchaser's side, the received Content 113 also needs to be processed to achieve a format appropriate for playback or transfer to a portable device. B. Function Partitioning and Flows The Rights Management Architectural Model is shown in FIG. 5 and this illustrates the mapping of the architectural layers to the operating components making up the Secure Digital Content Electronic Distribution System 100 and the key functions in each layer. 1. Content Formatting Layer 507 The general functions associated with the Content Formatting Layer 507 are Content Preprocessing 502 and Compression 511 at the Content Provider(s) 101, and Content De-scrambling 513 and Decompression 515 at the End-User Device(s) 109. The need for preprocessing and the examples of specific functions were mentioned above. Content Compression 511 is used to reduce the file size of the Content 113 and its transmission time. Any compression algorithm appropriate for the type of Content 113 and transmission medium can be used in the Secure Digital Content Electronic Distribution System 100. For music, MPEG ½/4, Dolby AC-2 and AC-3, Sony Adaptive Transform Coding (ATRAC), and low-bit rate algorithms are some of the typically used compression algorithms. The Content 113 is stored in the End-User Device(s) 109 in compressed form to reduce the storage size requirement. It is decompressed during active playback. De-scrambling is also performed during active playback. The purpose and type of scrambling will be described later during the discussion of the Content Usage Control Layer 505. 2. Content Usage Control Layer 505 The Content Usage Control Layer 505 permits the specification and enforcement of the conditions or restrictions imposed on the use of Content 113 use at the End-User Device(s) 109. The conditions may specify the number of plays allowed for the Content 113, whether or not a secondary copy of the Content 113 is allowed, the number of secondary copies, and whether or not the Content 113 may be copied to an external portable device. The Content Provider(s) 101 sets the allowable Usage Conditions 517 and transmits them to the Electronic Digital Content Store(s) 103 in a SC (see the License Control Layer 501 section). The Electronic Digital Content Store(s) 103 can add to or narrow the Usage Conditions 517 as long as it doesn't invalidate the original conditions set by the Content Provider(s) 101. The Electronic Digital Content Store(s) 103 then transmits all Store Usage Conditions 519 (in a SC) to the End-User Device(s) 109 and the Clearinghouse(s) 105. The Clearinghouse(s) 105 perform Usage Conditions Validation 521 before authorizing the Content 113 release to an End-User Device(s) 109. The enforcement of the content Usage Conditions 517 is performed by the Content Usage Control Layer 505 in the End-User Device(s) 109. First, upon reception of the Content 113 copy from the Content Identification Layer 503 in the End-User Device(s) 109 marks the Content 113 with a Copy/Play Code 523 representing the initial copy/play permission. Second, the Player Application 195 cryptographically scrambles the Content 113 before storing it in the End-User Device(s) 109. The Player Application 195 generates a scrambling key for each Content item, and the key is encrypted and hidden in the End-User Device(s) 109. Then, every time the End-User Device(s) 109 accesses the Content 113 for copy or play, the End-User Device(s) 109 verifies the copy/play code before allowing the de-scrambling of the Content 113 and the execution of the play or copy. The End-User Device(s) 109 also appropriately updates the copy/play code in the original copy of the Content 113 and on any new secondary copy. The copy/play coding is performed on Content 113 that has been compressed. That is, there is no need to decompress the Content 113 before the embedding of the copy/play code. The End-User Device(s) 109 uses a License Watermark 527 to embed the copy/play code within the Content 113. Only the End-User Player Application 195 that is knowledgeable of the embedding algorithm and the associated scrambling key is able to read or modify the embedded data. The data is invisible or inaudible to a human observer; that is, the data introduces no perceivable degradation to the Content 113. Since the watermark survives several steps of content processing, data compression, D-to-A and A-to-D conversion, and signal degradation introduced by normal content handling, the watermark stays with the Content 113 in any representation form, including analog representation. In an alternate embodiment, instead of using a License Watermark 527 to embed the copy/play code within the Content 113, the End-User Player Application 195 uses securely stored Usage Conditions 519. 3. Content Identification Layer 503 As part of the Content Identification Layer 503, the Content Provider(s) 101. also uses a License Watermark 527 to embed data in the Content 113 such as to the content identifier, content owner and other information, such as publication date and geographic distribution region. This watermark is referred to here as the Copyright Watermark 529. Upon reception, the End-User Device(s) 109 watermarks the copy of the Content 113 with the content purchaser's name and the Transaction ID 535 (see the License Control Layer 501 section below), and with other information such as date of license and Usage Conditions 517. This watermark is referred to here as the license watermark. Any copy of Content 113, obtained in an authorized manner or not, and subject to audio processing that preserves the content quality, carries the copyright and license watermarks. The Content Identification Layer 503 deters piracy. 4. License Control Layer 501 The License Control Layer 501 protects the Content 113 against unauthorized interception and ensures that the Content is only released on an individual basis to an End-User(s) that has properly licensed End-User Device(s) 109 and successfully completes a license purchase transaction with an authorized Electronic Digital Content Store(s) 103. The License Control Layer 501 protects the Content 113 by double Encryption 531. The Content 113 is encrypted using an encryption symmetric key generated by the Content Provider(s) 101, and the symmetric key is encrypted using the public key 621 of the Clearinghouse(s). Only the Clearinghouse(s) 105 can initially recover the symmetric key. License control is designed with the Clearinghouse(s) 105 as the "trusted party". Before releasing permission for the License Request 537, (i.e. the Symmetric Key 623 for the Content 113 to an End-User Device(s) 109), the Clearinghouse(s) 105 verifies that the Transaction 541 and the License Authorization 543 are complete and authentic, that the Electronic Digital Content Store(s) 103 has authorization from the Secure Digital Content Electronic Distribution System 100 for the sale of electronic Content 113, and that the End-User(s) has a properly licensed application. Audit/Reporting 545 allows the generation of reports and the sharing of licensing transaction information with other authorized parties in the Secure Electronic Digital Content Distribution System 100 License control is implemented through SC Processing 533. SC(s) are used to distribute encrypted Content 113 and information among the system operation components (more about the SC(s) detailed structure sections below). A SC is cryptographic carrier of information that uses cryptographic encryption, digital signatures and digital certificates to provide protection against unauthorized interception and modification of the electronic information or Content 113. It also allows for the authenticity verification of the electronic data. License control requires that the Content Provider(s) 101, the Electronic Digital Content Store(s) 103, and the Clearinghouse(s) 105 have bona-fide cryptographic digital certificates from reputable Certificate Authorities that are used to authenticate those components. The End-User Device(s) 109 are not required to have digital certificates. C. Content Distribution and Licensing Control FIG. 6 is a block diagram illustrating an overview of the Content Distribution and Licensing Control as it applies to the License Control Layer of FIG. 5. The figure depicts the case in which the Electronic Digital Content Store(s) 103, End-User Device(s) 109 and the Clearinghouse(s) 105 are interconnected via the Internet, and unicast (point-to-point) transmission is used among those components. The communication between the Content Provider(s) 101 and the Electronic Digital Content Store(s) 103 could also be over the Internet or other network. It is assumed that the Content-purchase commercial transaction between the End-User Device(s) 109 and the Electronic Digital Content Store(s) 103 is based on standard Internet Web protocols. As part of the Web-based interaction, the End-User(s) makes the selection of the Content 113 to purchase, provides personal and financial information, and agrees to the conditions of purchase. The Electronic Digital Content Store(s) 103 could obtain payment authorization from an acquirer institution using a protocol such as SET. It is also assumed in FIG. 6 that the Electronic Digital Content Store(s) 103 has downloaded the End-User Player Application 195 to an End-User Device(s) 109 based on standard Web protocols. The architecture requires that the Electronic Digital Content Store(s) 103 assigns a unique application ID to the downloaded Player Application 195 and that the End-User Device(s) 109 stores it for later application license verification (see below). The overall licensing flow starts at the Content Provider(s) 101. The Content Provider(s) 101 encrypts the Content 113 using an encryption symmetric key locally generated, and encrypts the Symmetric Key 623 using the Clearinghouse's 105 public key 621. In an alternate embodiment, the symmetric key instead of being locally generated my be sent to the Content Provider(s) 101 from the Clearinghouse(s) 105. The Content Provider(s) 101 creates a Content SC(s) 630 around the encrypted Content 113, and a Metadata SC(s) 620 around the encrypted Symmetric Key 623, Store Usage Conditions 519, and other Content 113 associated information. There is one Metadata SC(s) 620 and one Content SC(s) 630 for every Content 113 object. The Content 113 object may be a compression level one same song or the Content 113 object may be each song on the album or the Content 113 object may be the entire album. For each Content 113 object, the Metadata SC(s) 620 also carries the Store Usage Conditions 519 associated with the Content Usage Control Layer 505. The Content Provider(s) 101 distributes the Metadata SC(s) 620 to one or more Electronic Digital Content Store(s) 103 (step 601) and the Content SC(s) 630 to one or more Content Hosting Sites (step 602). Each Electronic Digital Content Store(s) 103, in turn creates an Offer SC(s) 641. The Offer SC(s) 641 typically carries much of the same information as the Metadata SC(s) 620, including the Digital Signature 624 of the Content Provider(s) 101 and the Certificate (not shown of the Content Provider(s) 101. As mentioned above, the Electronic Digital Content Store(s) 103 can add to or narrow the Store Usage Conditions 519 (handled by the Control Usage Control Layer) initially defined by the Content Provider(s) 101. Optionally, the Content SC(s) 630 and/or the Metadata SC(s) 620 is signed with a Digital Signature 624 of the Content Provider(s) 101. After the completion of the Content-purchase transaction between the End-User Device(s) 109 and the Electronic Digital Content Store(s) 103 (step 603), the Electronic Digital Content Store(s) 103 creates and transfers to the End-User Device(s) 109 a Transaction SC(s) 640 (step 604). The Transaction SC(s) 640 includes a unique Transaction ID 535, the purchaser's name (i.e. End-User(s)') (not shown), the Public Key 661 of the End-User Device(s) 109, and the Offer SC(s) 641 associated with the purchased Content 113. Transaction Data 642 in FIG. 6 represents both the Transaction ID 535 and the End-User(s) name (not shown). The Transaction Data 642 is encrypted with the Public Key 621 of the Clearinghouse(s) 105. Optionally, the Transaction SC(s) 640 is signed with a Digital Signature 643 of the Electronic Digital Content Store(s) 103. Upon reception of the Transaction SC(s) 640 (and the Offer SC(s) 641 included in it), the End-User Player Application 195 running on End-User Device(s) 109 solicits license authorization from the Clearinghouse(s) 105 by means of an Order SC(s) 650 (step 605). The Order SC(s) 650 includes the encrypted Symmetric Key 623 and Store Usage Conditions 519 from the Offer SC(s) 641, the encrypted Transaction Data 642 from the Transaction SC(s) 640, and the encrypted Application ID 551 from the End-User Device(s) 109. In another embodiment, the Order SC(s) 650 is signed with a Digital Signature 652 of the End-User Device(s) 109. Upon reception of the Order SC(s) 650 from the End-User Device(s) 109, the Clearinghouse(s) 10S verifies: If the verifications are successful, the Clearinghouse(s) 105 decrypts the Symmetric Key 623 and the Transaction Data 642 and builds and transfers the License SC(s) 660 to the End-User Device(s) 109 (step 606). The License SC(s) 660 carries the Symmetric Key 623 and the Transaction Data 642, both encrypted using the Public Key 661 of the End-User Device(s) 109. If any verification is not successful, the Clearinghouse(s) 105 denies the license to the End-User Device(s) 109 and informs the End-User Device(s) 109. The Clearinghouse(s) 105 also immediately informs the Electronic Digital Content Store(s) 103 of this verification failure. In an alternate embodiment, the Clearinghouse(s) 105 signs the License SC(s) 660 with its Digital Signature 663. After receiving the License SC(s) 660, the End-User Device(s) 109 decrypts the Symmetric Key 623 and the Transaction Data 642 previously received from the Clearinghouse(s) 105 and requests the Content SC(s) 630 (step 607) from a Content Hosting Site(s) 111. Upon arrival of the Content SC(s) 630 (step 608), the End-User Device(s) 109 decrypts the Content 113 using the Symmetric Key 623 (step 609), and passes the Content 113 and the Transaction Data 642 to the other layers for license watermarking, copy/play coding, scrambling, and further Content 113 processing as described previously for FIG. 5. Finally, the Clearinghouse(s) 105 on a periodic basis transmits summary transaction reports to the Content Provider(s) 101 and the Electronic Digital Content Store(s) 103 for auditing and tracking purposes (step 610). V. Secure Container Structure A. General Structure A Secure Container (SC) is a structure that consists of several parts which together define a unit of Content 113 or a portion of a transaction, and which also define related information such as Usage Conditions, metadata, and encryption methods. SC(s) are designed in such a way that the integrity, completeness, and authenticity of the information can be verified. Some of the information in. SC(s) may be encrypted so that it can only be accessed after proper authorization has been obtained. SC(s) include at least one bill of materials (BOM) part which has records of information about the SC(s) and about each of the parts included in the SC(s). A message digest is calculated, using a hashing algorithm such as MD-5, for each part and then included in the BOM record for the part. The digests of the parts are concatenated together and another digest is computed from them and then encrypted using the private key of the entity creating the SC(s) to create a digital signature. Parties receiving the SC(s) can use the digital signature to verify all of the digests and thus validate the integrity and completeness of the SC(s) and all of its parts. The following information may be included as records in the BOM along with the records for each part. The SC(s) type determines which records need to be included:
SC(s) may include more than one BOM. For example, an Offer SC(s) 641 consists of the original Metadata SC(s) 620 parts, including its BOM, as well as additional information added by the Electronic Digital Content Store(s) 103 and a new BOM. A record for the Metadata SC(s) 620 BOM is included in the Offer SC(s) 641 BOM. This record includes a digest for the Metadata SC(s) 620 BOM which can be used to validate its integrity and therefore, the integrity of the parts included from the Metadata SC(s) 620 can also be validated using the part digest values stored in Metadata SC(s) 620 BOM. None of the parts from the Metadata SC(s) 620 have records in the new BOM that was created for the Offer SC(s) 641. Only parts added by the Electronic Digital Content Store(s) 103 and the Metadata SC(s) 620 BOM have records in the new BOM. SC(s) may also include a Key Description part. Key Description parts include records that contain the following information about encrypted parts in the SC(s):
The Rights Management Language consists of parameters that can be assigned values to define restrictions on the use of the Content 113 by an End-User(s) after the Content 113 purchase. The restrictions on the use of the Content 113 is the Usage Conditions 517. Each Content Provider(s) 101 specifies the Usage Conditions 517 for each of its Content 113 items. Electronic Digital Content Store(s) 103 interpret the Usage Conditions 517 in Metadata SC(s) 620 and use the information to provide select options they wish to offer their customers as well as add retail purchase information for the Content 113. After an End-User(s) has selected a Content 113 item for purchase, the End-User Device(s) 109 requests authorization for the Content 113 based on Store Usage Conditions 519. Before the Clearinghouse(s) 105 sends a License SC(s) 660 to the End-User(s), the Clearinghouse(s) 105 verifies that the Store Usage. Conditions 519 being requested are in agreement with the allowable Usage Conditions 517 that were specified by the Content Provider(s) 101 in the Metadata SC(s) 620. When an End-User Device(s) 109 receives the Content 113 that was purchased, the Store Usage Conditions 519 are encoded into that Content 113 using the Watermarking Tool or encoded in the securely stored Usage Conditions 519. The End-User Player Application 195 running on End-User Device(s) 109 insures that the Store Usage Conditions 519 that were encoded into the Content 113 are enforced. The following are examples of Store Usage Conditions 519 for an embodiment where the Content 113 is music:
Metadata SC(s) 620 are built by Content Provider(s) 101 and are used to define Content 113 items such as songs. The Content 113 itself is not included in these SC(s) because the size of the Content 113 is typically too large for Electronic Digital Content Store(s) 103 and End-User(s) to efficiently download the containers just for the purpose of accessing the descriptive metadata. Instead, the SC(s) includes an external URL (Uniform Resource Locators) to point to the Content 113. The SC(s) also includes metadata that provides descriptive information about the Content 113 and any other associated data, such as for. music, the CD cover art and/or digital audio clips in the case of song Content 113. Electronic Digital Content Store(s) 103 download the Metadata SC(s) 620, for which they are authorized, and build Offer SC(s) 641. In short, an Offer SC(s) 641 consists of some of the parts and the BOM from the Metadata SC(s) 620 along with additional information included by the Electronic Digital Content Store(s) 103. A new BOM for the Offer SC(s) 641 is created when the Offer SC(s) 641 is built. Electronic Digital Content Store(s) 103 also use the Metadata SC(s) 620 by extracting metadata information from them to build HTML pages on their web sites that present descriptions of Content 113 to End-User(s), usually so they can purchase the Content 113. The information in the Offer SC(s) 641 that is added by the Electronic Digital Content Store(s) 103 is typically to narrow the selection of Usage Conditions 517 that are specified in the Metadata SC(s) 620 and promotional data such as a graphic image file of the store's logo and a URL to the store's web site. An Offer SC(s) 641 template in the Metadata SC(s) 620 indicates which information can be overridden by the Electronic Digital Content Store(s) 103 in the Offer SC(s) 641 and what, if any, additional information is required by the Electronic Digital content Store(s) 103 and what parts are retained in the embedded Metadata SC(s) 620. Offer SC(s) 641 are included in a Transaction SC(s) 640 when an End-User(s) decides to purchase Content 113 from an Electronic Digital Content Store(s) 103. The Electronic Digital Content Store(s). 103 builds a Transaction SC(s) 640 and includes Offer SC(s) 641 for each Content 113 item being purchased and transmits it to the End-User Device(s) 109. The End-User Device(s) 109 receives the Transaction SC(s) 640 and validates the integrity of the Transaction SC(s) 640 and the included Offer SC(s) 641. An Order SC(s) 650 is built by the End-User Device(s) 109 for each Content 113 item being purchased. Information is included from the Offer SC(s) 641, from the. Transaction SC(s) 640, and from the configuration files of the End-User Device(s) 109. Order SC(s) 650 are sent to the Clearinghouse(s) 105 one at a time. The Clearinghouse(s) 105 URL where the Order SC(s) 650 is included as one of the records in the BOM for the Metadata SC(s) 620 and included again in the Offer SC(s) 641. The Clearinghouse(s) 105 validates and processes Order SC(s) 650 to provide the End-User Device(s) 109 with everything that is required to a License Watermark 527 and access purchased Content 113. One of the functions of the Clearinghouse(s) 105 is to decrypt the Symmetric Keys 623 that are needed to decrypt the watermarking instructions from the Offer SC(s) 641 and the Content 113 from the Content SC(s) 630. An encrypted Symmetric Key 623 record actually contains more than the actual encrypted Symmetric Key 623. Before executing the encryption, the Content Provider(s) 101 may optionally append its name to the actual Symmetric Key 623. Having the Content Provider(s)' 101 name encrypted together with the Symmetric Key 623 provides security against a pirate Content Provider(s) 101 that has built its own Metadata SC(s) 620 and Content SC(s) 630 from legal SC(s). The Clearinghouse(s) 105 verifies that the name of the Content Provider(s) 101 encrypted together with the Symmetric Keys 623 matches the name of the Content Provider(s) 101 in the SC(s) certificate. If there are any changes required to be made to the watermarking instructions by the Clearinghouse(s) 105, then the Clearinghouse(s) 105 decrypts the Symmetric Key 623 and then modifies the watermarking instructions and encrypts them again using a new Symmetric Key 623. The Symmetric Key 623 is then re-encrypted using the Public Key 661 of the End-User Device(s) 109. The Clearinghouse(s) 105 also decrypts the other Symmetric Keys 623 in the SC(s) and encrypts them again with the Public Key 661 of the End-User Device(s) 109. The Clearinghouse(s) 105 builds a License SC(s) 660 that includes the newly encrypted Symmetric Keys 623 and updated watermarking instructions and sends it to the End-User Device(s) 109 in response to the Order SC(s) 650. If the processing of the Order SC(s) 650 does not complete successfully, then the Clearinghouse(s) 105 returns to the End-User Device(s) 109 an HTML page or equivalent reporting the failure of the authorization process. A License SC(s) 660 provides an End-User Device(s) 109 with everything that is needed to access a Content 113 item. The End-User Device(s) 109 requests the appropriate Content SC(s) 630 from the Content Hosting Site(s). 111. Content SC(s) 630 are built by Content Provider(s) 101 and include encrypted Content 113 and metadata parts. The End-User Player Application 195 uses the Symmetric Keys 623 from the License SC(s) 660 to decrypt the Content 113, metadata, and watermarking instructions. The watermarking instructions are then affixed into the Content 113 and the Content 113 is scrambled and stored on the End-User Device(s) 109. D. Metadata Secure Container 620 Format The following table shows the parts that are included in a Metadata SC(s) 620. Each box in the Parts column is a separate object included in the SC(s) along with the BOM (with the exception of part names that are surrounded by [ ] characters). The BOM contains a record for each part included in the SC(s). The Part Exists column indicates whether the part itself is actually included in the SC(s) and the Digest column indicates whether a message digest is computed for the part. Some parts may not be propagated when a SC(s) is included in other SC(s) (as determined by the associated template), although the entire original BOM is propagated. This is done because the entire BOM is required by the Clearinghouse(s) 105 to verify the digital signature in the original SC(s). The Key Description Part columns of the following table define the records that are included in the Key Description part of the SC(s). Records in the Key Description part define information about the encryption keys and algorithms that were used to encrypt parts within the SC(s) or parts within another SC(s). Each record includes the encrypted part name and, if necessary, a URL that points to another SC(s) that includes the encrypted part. The Result Name column defines the name that is assigned to the part after it is decrypted. The Encrypt Alg column defines the encryption algorithm that was used to encrypt the part. The Key Id/Enc Key column defines either an identification of the encryption key that was used to encrypt the part or a base64 encoding of the encrypted Symmetric Key 623 bit string that was used to encrypt the part. The Sym Key Alg column is an optio | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||