Content distribution program, content distribution method, server, content utilization apparatus, and content utilization system

An encrypted content and a license are separated from each other to be distributed individually, so that the encrypted content is decrypted using the license in a user apparatus. A server encrypts licenses of a plurality of encrypted contents for package sale to generate an inactive license packaged in one file and distribute the inactive license to a user terminal utilizing an activation license for package sale. An activation license for package sale is distributed in response to a purchase request from the user terminal, a plurality of encrypted licenses contained in the inactive license are decrypted, an encrypted content contained in an object for package sale is decrypted using a license corresponding thereto so that the decrypted content is reproduced.

FIELD OF THE INVENTION

Recently, according to higher speed and larger capacity of a network, and higher performance of a personal computer, contents such as music, video, photography document, or the like are digitized and they are widely distributed on Internet or though movable mediums such as a DVD.

DESCRIPTION OF RELATED ART

Since such digital content can be copied easily, and degradation thereof due to the copying is slight, Digital Right Management system (DRM) for protecting the content such that digital data of the content is not exposed is inevitable in content distribution on network or through a mobile medium. In the DRM, content is encrypted and distributed, while a user acquires a license to decrypt the encrypted content and reproduce the same. In such a distribution system for digital contents, super-distribution where content and its license are distributed independently of each other have been known, where, when a user wish to acquire and reserve an encrypted content from a content distribution server or a mobile medium without charge to reproduce the same, he/she purchases a license from the content distribution server and decrypts the encrypted content according to the purchased license to reproduce and utilize the content. Further, sales of digital content include a package sale for selling a plurality of contents collectively besides individual utilizations of individual contents. The package sale is, for example, an album sale of music contents and it takes a system similar to a system where CDs are produced and sold for each album. In the package sale of digital contents, a plurality of contents are encrypted according to a license to a package and an encrypted content package file packaged to one file is generated and distributed. Simultaneously, a license used for packaging is distributed in response to a purchase request from a user for his/her utilization.Patent Literature 1: JP-A-2001-094549Patent Literature 2: JP-A-2003-187017Patent Literature 3: JP-A-2003-218851Patent Literature 4: JP-A-2002-108710

In such a conventional package sale of digital contents, however, individual contents are encrypted and distributed, and even if licenses for the individual contents have been already sold out, when these contents are collected and sold as a package, contents are encrypted and distributed for each package again, which results in trouble and increase in cost.

In a user apparatus, in addition to individual encrypted contents, a storing region for a package including these contents is required, and when the encrypted contents are redundantly reserved and the encrypted contents are copied in a built-in fixed hard disk and utilized in the user apparatus, such a problem arises that the storing region of the user apparatus is used wastefully.

Further, when an encrypted content is distributed using a mobile medium such as a CD or a DVD, encrypted contents which are individually sold are redundantly distributed for a package sale, which results in requirement for more mobile mediums. As a result, when the number of packages to which one content belongs is increased, an operational cost increases and user burden becomes large.

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide a content distribution program and method, a server, and a content utilization apparatus and system, where regarding package sales of contents, a package including licenses of a plurality of encrypted contents for package sale is encrypted and distributed, and an operation cost for encrypted contents for the package sale is reduced using the encrypted contents distributed with individual licenses.

One aspect of the present invention provides a content distribution program executed by a computer constituting a server.

The content distribution program of the present invention causes a computer constituting a server which separates an encrypted content and a license from each other to distribute the encrypted content and the license individually. The program also causes a user apparatus and to decrypt the encrypted content to reproduce the same based upon the license. The program causes the server to generate an activation license for package sale, and encrypt licenses of a plurality of encrypted contents for package sale using the activation license to generate an inactive license packaged to one file.

The server then distributes the inactive license to a user terminal. When the server receives and processes a purchase request of the package from the user terminal, the program causes the server to distribute the activation license for decrypting a plurality of encrypted licenses contained in the inactive license and decrypting an encrypted content contained in an object for the package sale using a license corresponding thereto to reproduce the decrypted content.

Here, the activation license generating step generates the activation license including a cryptography key encrypting the licenses of a plurality of encrypted contents for package sale and a permission condition of the plurality of encrypted contents for package sale.

The inactive license generating step stores the inactive license together with the encrypted contents in a mobile medium to provide the mobile medium to the user apparatus.

The inactive license generating step generates the inactive license incorporated with metadata constituting an album with contents to be packaged in addition to the cryptography key and the permission condition. The user apparatus reads a plurality of encrypted contents corresponding to the metadata of the inactive license to reproduce contents according to the constitution of the album.

Another aspect of the present invention provides a content utilization program executed by a computer constituting a user apparatus.

The content utilization program of the present invention causes a computer constituting a user apparatus which acquires an encrypted content and a license thereof provided separately to decrypt the encrypted content based on the license and reproduce the same to execute;

a content acquiring step of acquiring a plurality of encrypted contents for package sale to reserve the encrypted contents;

an inactive license acquiring step of encrypting licenses of a plurality of encrypted contents for package sale using an activation license to acquire and reserve an inactive license packaged to one file;

an activation license acquiring step of acquiring and reserving an activation license corresponding to the inactive license according to a package purchase request to the server;

an inactive license activating step of decrypting a plurality of encrypted licenses contained in the inactive license utilizing the activation license and storing the decrypted licenses in a secure license management database; and

a content reproduction processing step of decrypting an encrypted content contained in an object for the package sale using a corresponding license to reproduce the decrypted content.

Here, the activation license includes a cryptography key encrypting the licenses of a plurality of encrypted contents for package sale and a permission condition to the plurality of encrypted contents for package sale.

The encrypted content acquiring step and the inactive license acquiring step read and reserve an encrypted content and an inactive license stored in a mobile medium.

The content reproduction processing step decrypts an acquired single encrypted content by searching a license corresponding thereto and stored in the license management database and using the searched license to reproduce the acquired single encrypted content.

The inactive license acquiring step acquires an inactive license incorporated with metadata constituting an album with contents to be packaged in addition to the cryptography key and the permission condition, and the content reproduction processing step acquires a plurality of encrypted contents corresponding to the metadata of the inactive license to reproduce the contents according to the constitution of the album.

Still another aspect of the present invention is a content distribution method which separates an encrypted content and a license thereof to distribute the content and the license individually, and causes a user apparatus to decrypt the encrypted content based upon the license and reproduce the decrypted content. According to the method, the server generates an activation license for package Sale and encrypts licenses of a plurality of encrypted contents for package sale using the activation license to generate an inactive license packaged to one file. The server then distributes the inactive license to a user terminal.

When the server receives and processes a purchase request of the package from the user terminal, the server distributes the activation license corresponding to the inactive license.

Here, the activation license generating step generates the activation license including a cryptography key encrypting the licenses of a plurality of encrypted contents for package sale and a permission condition of the plurality of encrypted contents for package sale.

The inactive license generating step stores the inactive license together with the encrypted contents in a mobile medium to provide the mobile medium to the user apparatus.

The inactive license generating step generates the inactive license incorporated with metadata constituting an album with contents to be packaged in addition to the cryptography key and the permission condition. The user apparatus reads a plurality of encrypted contents corresponding to the metadata of the inactive license to reproduce contents according to the constitution of the album.

Another aspect of the present invention is a content utilization method which acquires an encrypted content and a license thereof provided separately to decrypt the encrypted content based on the license to reproduce the same, comprising:

a content acquiring step of acquiring and reserving a plurality of encrypted contents for package sale;

an inactive license acquiring step of encrypting licenses of a plurality of encrypted contents for package sale using an activation license to acquire and reserve an inactive license packaged to one file by;

an activation license acquiring step of acquiring and reserving an activation license according to a package purchase request to the server;

an inactive license activating step of decrypting a plurality of encrypted licenses contained in the inactive license utilizing the activation license and storing the decrypted licenses in a secure license management database; and

a content reproduction processing step of decrypting an encrypted content contained in an object for the package sale using a license corresponding to the encrypted content according to content information of the inactive license to reproduce the content.

Yet another aspect of the present invention is a content distribution apparatus (a server) which separates an encrypted content and a license thereof from each other to distribute the content and the license individually and causes a user apparatus to decrypt the encrypted content based upon the license and reproduce the decrypted content, including an activation license generating unit which generates an activation license for package sale, and an inactive license generating unit that encrypts licenses of a plurality of encrypted contents for package sale using the activation license to generate an inactive license packaged to one file.

An inactive license distributing unit distributes the inactive license to a user terminal, and an activation license activating unit, when receiving and processing a purchase request of a package from the user terminal, distributes the activation license to decrypt a plurality of encrypted licenses included in the inactive license and stores the plurality of encrypted licenses decrypted in a secure license management database. An activation license distributing unit decrypts an encrypted content contained in an object for the package sale using a license corresponding to the encrypted content according to content information of the inactive license to reproduce the decrypted content.

Further, another aspect of the present invention is a content utilization apparatus (a server) which acquires an encrypted content and a license thereof provided separately to decrypt the encrypted content based on the license to the same, comprising:

a content acquiring unit which acquires and reserves a plurality of encrypted contents for package sale;

an activation license acquiring unit which encrypts licenses of a plurality of encrypted contents for package sale using an activation license to acquire and reserve an inactive license packaged to one file by;

an activation license acquiring unit which acquires and reserves an activation license according to a package purchase request to the server;

an inactive license activation processing unit which decrypts a plurality of encrypted licenses contained in the inactive license utilizing the activation license and stores the decrypted licenses in a secure license management database; and

a content reproduction processing unit which decrypts an encrypted content contained in an object for the package sale using a license corresponding to content information of the inactive license to reproduce the decrypted content.

The present invention also includes a content distribution system where an encrypted content and a license thereof are separated from each other and are distributed individually by a content distribution apparatus (a server) and the encrypted content is decrypted based upon the license and is reproduced by a content utilization apparatus (a user apparatus), wherein

the content distribution apparatus comprises:

an activation license generating unit which generates an activation license for package sale;

an inactive license generating unit which encrypts licenses of a plurality of encrypted contents for package sale using the activation license to generate an inactive license packaged to one file by;

an inactive license distributing unit which distributes the inactive license to a user terminal; and

an activation license distributing unit which distributes the activation license when receiving a purchase request from the user terminal to process the same, and

the content utilization apparatus comprises

a content acquiring unit which acquires and reserves the encrypted content;

an inactive license acquiring unit which acquires and reserves the inactive license;

an activation license acquiring unit which acquires and reserves the activation license according to a package purchase request to the content distribution apparatus;

an inactive license activation processing unit which decrypts a plurality of encrypted licenses included in the inactive license using the activation license to store the plurality of encrypted licenses decrypted into a secure license management database; and

a content reproduction processing unit which decrypts an encrypted content contained in an object for the package sale using a license corresponding thereto according to content information of the inactive license to reproduce the decrypted content.

Incidentally, the details of the method, the server, and the content utilization apparatus and system are basically the same as those of the content distribution program and content utilization program.

According to various aspects of the present invention, regarding package sale of a plurality of encrypted contents, since the encrypted contents which have been already distributed individually for license sale are utilized, an inactive license packaged to one file by encrypting licenses of encrypted contents for package is generated and distributed without generating encrypted contents newly, and a user is required to only sell an activation license for decrypting the encrypted licenses contained in the inactive license, so that an operational cost of the encrypted contents in a package sale is reduced and simultaneously a storing region of encrypted contents in the user apparatus can be reduced by the individual sale and the package sale sharing the encrypted contents. Further, even if encrypted contents are distributed using mobile mediums such as a DVD, the number of mediums to be used can be restricted to the necessity minimum.

DETAILED DESCRIPTION

FIG. 1is a block diagram of a system configuration of the present invention for package sale of contents. InFIG. 1, a content distribution system is configured with a server10functioning as a center apparatus on a content distribution side and a user apparatus (a content utilization apparatus)12functioning as a client. Of course, a plurality of user apparatuses12may be present corresponding to the server10, but a configuration having only one user apparatus12is explained as an example. The server10is provided with an encrypted content generating unit14, a license generating unit16, an inactive license generating unit28, an activation license generating unit34, a mobile medium recorder38, and a license distributing unit40. The server10includes a content data file18, an encrypted parameter file20, a content permission condition file22, an encrypted content file24, a license file26, an inactive license file30, a package permission condition file32, and an activation license file36as data files used in respective processing units. The encrypted content generating unit14in the server10encrypts individual contents stored in the content data file18using a cryptography key used in a license for content generated in the license generating unit16to generate encrypted contents, and stores the encrypted contents in the encrypted content file24. The encrypted contents are stored in the encrypted content file24for respective individual contents. The license generating unit16generates licenses to respective contents encrypted by the encrypted content generating unit14. In generation of licenses for content, a license is generated by acquiring a cryptography key from the encrypted parameter file20and acquiring a permission condition from the content permission condition file22. Generations of an encrypted content and a license thereof performed by the encrypted content generating unit14and the license generating unit16correspond to processing portions for respective contents in the conventional system. In addition thereto, a license for selling a plurality of contents as a package is generated by the inactive license generating unit28and the activation license generating unit34in the present invention. The activation license generating unit34generates an activation license for package sale used for encrypting licenses of a plurality of encrypted contents. That is, the activation license generating unit34acquires a permission condition required for package sale from the package permission condition file32and acquires a cryptography key from the license file26to generate an activation license. The activation license generated in the activation license generating unit34is stored the activation license file36. The inactive license generating unit28acquires licenses of a plurality of encrypted contents for package sale from the license file26and generates an inactive license packaged in one file by encrypting each license using a cryptography key of activation license generated in the activation license generating unit34, and stores the generated inactive license in the inactive license file30. In this embodiment, the mobile medium recorder38records an encrypted content stored in the encrypted content file24and an inactive license stored in the inactive license file30in a mobile medium42to distribute the same in the market. As the mobile medium, a CD, a DVD, a removable HD, or the like is used. The reason why the mobile medium42is used for distribution of content is because a data amount of encrypted contents and an inactive license for package sale is voluminous, which would result in an increase of cost in network communication. Of course, if a problem about the communication cost is overcome, encrypted contents and an inactive license for package sale may be network-distributed through the network44instead of or in addition to distributing on mobile mediums. When the license distributing unit40receives a content purchase request of contents packaged from the user apparatus12and completes a purchase processing, it distributes a corresponding activation license stored in the activation license file36to the user apparatus12through the network44. Here, the contents distributed from the server10include any contents such as music, video, Karaoke, map, game, electronic book, or Rakugo. Distribution of contents from the server10is performed through a so-called “super-distribution” where content and license are respectively encrypted to be put in distribution. In the following explanation, the encrypted content file24, the inactive license file30, and the activated license file36may be simply expressed as an encrypted content24, an inactive license30, and an activated license36.

As shown inFIG. 2, the user apparatus12functioning as a content utilization apparatus is provided with a content acquiring unit46, a content management database48, an inactive license acquiring unit50, an inactive license activation processing unit51, an activation license acquiring unit52, a license management data54, a digital right managing unit56, an application processing unit58, and a reproduction player unit60. As the user apparatus12, there are a personal computer, a PDA, a vehicle-mounted terminal, an STB, a portable phone, and the like. When a mobile medium42is loaded in a drive, the content acquiring unit46in the user apparatus12reads an encrypted content stored in the mobile medium42to store the same in the content management database48, and when an inactive license used in package sale is stored in the mobile medium42, the inactive license acquiring unit50reads an inactive license to store the same in the content management database48. The content acquiring unit46acquires encrypted contents which are individually distributed to reserve them in the content management database48directly regardless of contents for package sale distributed from the server10. Therefore, when contents sold as a package should be reproduced in the user apparatus12, all encrypted contents for package are not reserved in the content management database48necessarily, and when contents sold as a package are utilized according to license acquisition, an encrypted content which is contained in a content object but is not reserved is newly acquired through a mobile medium42or a network distribution to be reserved in the content management database48. That is, a license acquired for package sale and contents to be sold as a package are distributed separately, where, regarding the contents, only distribution of encrypted contents is performed assuming utilization of individual contents using licenses but contents for such a system where package sale are collectively encrypted and distributed is not adopted. When a license of a plurality of contents sold as a package (for example, contents taking an album configuration), should be acquired, the activation license acquiring unit52issues a purchase request of an activation license required for reproduction of the contents sold as a package to the server10and it acquires an activation license for a package sale via the network44from the server10to store the same in the license management database54after a charging processing to the purchase request has been terminated and a purchase processing has been terminated. The digital right managing unit56functions as a DRM client to the server10and acquires an activation license from the license management database54in the inactive license activation processing unit51based upon user's content selection to display a menu of contents, for example, having an album configuration, for package sale performed by the application processing unit58. The digital right managing unit56acquires an inactive license for package from the content management database48to decrypt encrypted licenses corresponding to a plurality of encrypted contents contained in the inactive license according to the cryptography key of the activation license, and stores decrypted licenses key for contents in the license management database54. Thereafter, the digital right managing unit56reads an inactive license for package sale corresponding to the selected menu from the content management database48, reads a corresponding encrypted content from the content management database48according to content information in the inactive license, acquires the license for content from the license management database54, decrypts the encrypted content using the cryptography key of the license for content to generate content data, and outputs the content data to the reproduction player unit60, where an reproducing operation of the content is performed. That is, the digital right managing unit56functions as a content reproduction processing unit in the user apparatus12and decrypts an encrypted content included in encrypted contents for package sale according to content information in the inactive license to reproduce the content.

FIG. 3is a block diagram of a hardware environment of a computer applied to the sever10shown inFIG. 1. In the computer shown inFIG. 2, a bus201of a CPU200is connected with a RAM202, a hard disk controller (soft)204, a floppy disk drive (soft)210, a CD-ROM drive (soft)214, a mouse controller218, a keyboard controller222, a display controller226, and a communication board230. The hard disk controller204is connected with a hard disk drive206, and is loaded with programs executing a content distribution processing for a package sale of the present invention, and it calls a required program from the hard disk drive206to develop the same on the RAM202and causes the CPU200to execute it at an activation of the computer. The floppy disk driver210is connected with a floppy disk drive (hard)212, and it can perform reading and writing to a floppy disk (R). A CD-ROM214is connected with a CD drive (hard)216and it can read data or a program stored in a CD. The mouse controller218transmits an input operation of a mouse220to the CPU200. The keyboard controller222transmits an input operation of a keyboard224to the CPU200. The display controller226performs display on a display unit228. A communication board230uses a communication line232including wireless to perform communication with apparatuses within a network or an apparatus via LAN on external Internet.

FIG. 4is a block diagram of the user apparatus shown inFIG. 2provided with a digital right management function (DRM function). InFIG. 4, the user apparatus12is composed of tamper resistant modules (TRMs)62and64. The TRM62is provided with a license control unit66and a command control unit68. The command control unit68includes a license acquiring unit70, a license storing unit72, and a license searching unit74. The TRM62performs reservation, search, and read of a license to the license management database54. The TRM64includes an inactive license activation processing unit72, an encrypted content decrypting unit78, decrypted content data80, a CODIC decoder82, and a reproducing unit84. A section including the license control unit66, the command control unit68, the inactive license acquiring unit76, and the encrypted content decrypting unit78constitutes the client DRM unit65according to the present invention to the TRMs62and64. The TRMs62and64are established using a hardware and a software for protection from unauthorized access performed by a third party. IEEE1394 or DTPC (Dynamic Tuning Control Protocol) is used in connection of a device of a mobile medium to the TRMs62and64, for example, in such a case that a drive is connected via a USB port, where encrypted data is transmitted and received. When a LAN is used via the network44, encryption transmission using SSL (Secure Socket Layer) or IPSEC (IP Security Protocol) is adopted. In data transmission between the user apparatus12and the server10, after mutual authentication and exchange of keys are conducted between the both, for example, data transmission of an activation license encrypted according to a hybrid system is performed. In encryption according to the hybrid system, pseudo-random number is generated to generate a session key on the side of a transmission and the session key is encrypted using a public key of a reception side obtained by the first key exchange, while a transmission message is transmitted after it is encrypted using the session key to be connected. On the reception side, a received encrypted session key is decrypted based upon an encrypted secret key (private key) and the received encrypted message is decrypted using the decrypted session key. In a processing operation in the user apparatus12shown inFIG. 4, the inactive license acquiring unit76provided in the TRM62reads an inactive license30for a package sale from such a mobile medium as a DVD to reserve the same in the content management database48. The license acquiring unit70acquires an activation license38corresponding to the inactive license30via the network44according to a purchase request for a package to reserve the license38in the license management database54via the license control unit66. In reproduction of contents sold as a package, the inactive license activation processing unit77provided on the side of the TRM64reads the inactive license30corresponding to a package to be reproduced from the content management database48and acquires an activation license corresponding to the inactive license30through access to the license searching unit74. Encrypted licenses of a plurality of contents contained in the inactive license is decrypted using the cryptography key of the acquired activation license and the encrypted licenses for the plurality of contents are reserved in the license management database54. Then, an encrypted content75to be reproduced is read from the content management database48according to content information in the inactive license based upon menu selection of contents contained in the package, a license for content corresponding thereto is read from the license management database54, the encrypted content to be reproduced is decrypted using the cryptography key of the content license, and a decrypted content data80is outputted. An output of the decrypted content data80complies with a permission condition contained in a license. Since the utilization period or the number of utilization times is set as the permission condition contained in the license, when the condition is satisfied, the encrypted content is decrypted using the cryptography key and a decrypted content80is outputted. The CODIC decoder82is inputted with the decrypted content data80and the decrypted content data80is reproduced and outputted at the reproducing unit84.

FIGS. 5A and 5Bare explanatory diagrams showing encrypted contents, an inactive license, andan activation license together with licenses for individual sale. InFIGS. 5A and 5B, three contents86,88, and90are shown as examples, where licenses104-1,106-1, and108-1are generated for individual distributions of the contents86,88, and90. A cryptography key92and a permission condition110are contained in the license104-1, and the content86is encrypted using a cryptography key92of the license104-1so that an encrypted content98is generated. Therefore, regarding the content86, the encrypted content98and the license104-1are distributed individually. Regarding the content88, the license106-1is generated, a permission condition110and a cryptography key94are contained in the license106-1, the content88is encrypted using the cryptography key94, and an encrypted content100is generated, so that the encrypted content100and the license106-1are distributed individually. Regarding the content90, the license108-1is generated, where a permission condition112and a cryptography key96are contained. The content90is encrypted using the cryptography key96of the license108-1to generate an encrypted content102. Therefore, regarding the content90, the encrypted content102and the license108-1are distributed individually. Contrary to the encrypted content and the license for each content, in the package sale according to the present invention, after a license containing the cryptography keys92,94, and96used for encryption of the contents86,88, and90and a permission condition115unique for package sale is generated, encrypted licenses104-2,106-2, and108-2obtained by encrypting respective licenses using a cryptography key116contained in an activation license118are generated, and an inactive license114is generated by collecting these encrypted licenses into one file. The activation license118contains the cryptography key116and a permission condition120. Regarding the permission condition120, permission conditions such as (1) the number of reproducible times n, (2) a reproducible period, and (3) the number of reproducible bytes are set for package sale of three contents86,88, and90in this example. The content of the permission condition120is basically similar to those of the permission conditions110,112, and115in individual license. In such package sale according to the present invention, the inactive license file114is distributed in the market using such a mobile medium such as a DVD without charge, but the activation license118containing the cryptography key116for decrypting the encrypted licenses104-2,106-2, and108-2contained in the inactive license114is distributed in the market for profit except for a trial package. On the other hand, the encrypted contents98,100, and102to be sold as a package are distributed as individual contents separately from the package sale, where when the contents to be sold as a package are reused, if the user apparatus has acquired encrypted contents98,100, and102in advance, it decrypts them as the encrypted contents to be sold as a package to utilize them. Therefore, according to the present invention, it is unnecessary to generate encrypted contents for the package sale again, where utilization of contents for package sale is realized by sharing encrypted contents in individual contents.

FIGS. 6A and 6Bare explanatory diagrams of a permission condition file provided in the server shown inFIG. 1,FIG. 6Ashowing a content permission condition file22, andFIG. 6Bshowing a package permission condition file32. The content permission condition file22shown inFIG. 6Ais composed of content ID, the number of reproduction times, reproducible period, the number of reproducible bytes and price. For example, referring to content ID=001, the number of reproduction times is three, the reproducible period expires on 1 Sep. 2006, the number of reproducible bytes is 1 MB, and the price is charge-free. The permission condition of the content ID001is scheduled for the so-called charge-free trial utilization of content to a user. Regarding the next content ID002, the number of reproduction times is unlimited, the reproducible period expires on 1 Apr. 2006, the number of reproducible bytes is 4 MB, and the price is 700 yen. Thus, one of permission conditions preliminarily prepared in the content permission condition file22as templates is selected and it is used when a license is generated inFIG. 4. The package permission condition file32shown inFIG. 6Bis composed of package ID, the number of reproduction times, reproducible period, the number of reproducible bytes, and price. For example, taking package ID=001 as an example, the number of reproduction times is three, the reproducible period expires on 1 Sep. 2006, the number of reproducible bytes is 1 MB, and the price is charge-free. This is a permission condition applied when an activation license is provided to a user without charge in package sale and trial utilization is performed. On the other hand, in package ID=002, the number of reproduction times is unrestricted, the reproducible period expires when 6 months elapses from a purchase month, and the price is 1500 yen. This means a permission condition applied, for example, when the package utilized under the permission condition of the package ID001in the trial manner is then utilized by the user for profit. Regarding the contents in the package permission condition file32, templates of a plurality of permission conditions are prepared according to necessity and a condition required is selected from the permission conditions, so that it is used as the permission condition115when the inactive license file114show inFIG. 4is generated.

FIG. 7is an explanatory diagram of a generation function of a license for package sale in the server10shown inFIG. 1, where a case that the three contents86,88, and90shown inFIGS. 5A and 5Bare configured as a package is taken an example. InFIG. 7, in the server10, content licenses104-1,106-1, and108-1are generated corresponding to the three encrypted contents98,100,102to be sold as a package. A cryptography key92and a permission condition115are contained in the content license104-1, a cryptography key94and the same permission condition115are contained in the content license106-1, and a cryptography key96and the permission condition115are contained in the content license108-1. After an encrypting processing122is performed to the three content licenses104-1,106-1, and108-1for package sale thus generated using the cryptography key116for an activation license, a packaging processing124is performed, so that an inactive license114storing the encrypted content licenses104-2,106-2, and108-2in one file is generated. On the other hand, regarding the cryptography key116for an activation license, an activation license118containing the cryptography key116and the permission condition120of the package is generated by the activation license generation126. The encrypted contents98,100, and102, and the inactive license114generated in the server10are provided to the user apparatus12by storing them in a mobile medium42to distribute the mobile medium42. On the other hand, regarding the activation license118, when the server10receives a package purchase request from the user apparatus12where purchasing contract is approved, the activation license118is distributed via the network44, the encrypted licenses104-2,106-2, and108-2in the inactive license file114are decrypted so that decryption and utilization of the encrypted contents98,100, and102can be made possible.

FIG. 8is an explanatory diagram of a data structure of the inactive license114generated by the server10of the present invention. InFIG. 8, the inactive license114is composed of header130storing the number of elements and the like, element information132, the number of elements134-1to134-ncorresponding to the number n of contents for package, and electronic signature136. The element information132includes individual element information pieces138-1to138-ncorresponding to the elements134-1to134-n, as shown in a lower side thereof. Regarding the individual element information pieces138-1to138-n, each individual element piece is composed of content ID140, content information141, encrypted content file name142, license identification information144such as a permission condition, offset of element in file146, and element decrypting information148such as a cryptography block size, as shown on a lower side of the leading individual element information piece138-1. On the other hand, regarding the elements134-1to134-n, each element is composed of size150and encrypted license key152which is a license key encrypted using a cryptography key of an activation license, as shown on an upper side of the leading element134-1. Here, the encrypted license key152in the element134-1is data obtained by encrypting the cryptography key92using the cryptography key116of the activation license118in the case of the encrypted license104-2shown inFIGS. 5A and 5B.

FIG. 9is an explanatory diagram of a data structure of an activation license generated according to the present invention. InFIG. 9, the activation license118is composed of header160such as the number of elements, element information162, element164, and electronic signature166. In this case, since the number of elements is one, the numbers of the element information162and the element164are each one. The element information162is composed of license ID168, inactive license file name170, license identification information172such as permission condition, and offset in file of element174, as shown on a lower side thereof. The element164is composed of size176and inactive license cryptography key178, as shown on an upper side thereof.

FIG. 10is an explanatory diagram of a data structure of an encrypted content generated according to the present invention. InFIG. 10, the encrypted content98is composed of header180such as the number of elements, element information182, and element184. In this case, since the number of elements is one, the number of the element information182is also one. The element information182is composed of content ID, license identification information118such as a permission condition, offset in file of element190, and element decrypting information192such as a cryptography block size, as shown on a lower side thereof. The element184is composed of size194and encrypted content196, as shown on an upper side thereof.

FIGS. 11A and 11Bare time charts of a content distribution processing and a utilization processing in the server10shown inFIG. 1and the user apparatus12shown inFIG. 2. InFIGS. 11A and 11B, the server10individually generates content licenses including a content cryptography key and a permission condition for respective encrypted contents for ordinary sale of contents to circulate the encrypted contents and the content licenses separately from each other at step S1. When a plurality of contents are sold as a package, regarding a plurality of contents for package sale, the server10generates a content license for package sale including the same cryptography key as used for content encryption for individual sale and a permission condition in package sale at step S2. Then, the server10encrypts licenses of respective contents for package sale using a cryptography key contained in the activation license and collects the encrypted licenses in one file to generate an inactive license at step S3. Subsequently, the server10generates an activation license including an activation cryptography key used for encrypting the content license in the inactive license and a permission condition for package sale at step S4. The server10instructs distribution in a state that the inactive license has been stored in a mobile medium such as a DVD together with the encrypted contents according to necessity at step S5. On the other hand, the user apparatus12reads and reserves the inactive license from the mobile medium provided from the server10at step S101. Since a content menu for package sale is contained in the inactive license, the user apparatus12develops a package menu according to application and selects a desired package from the developed menu to issue a purchase request to the server10at step S102. The server10which has received the purchase request for a package from the user apparatus12makes determination about the purchase request for a package at step S6, it distributes a requested activation license to the user apparatus12after package sale completion according to an accounting processing such as user's credit settlement at step S7. The user apparatus12receives and reserves the activation license distributed from the server10at step S103. Next, when the user apparatus12selects a reproduction content desired by a user from the package menu at step S104, it decrypts a plurality of encrypted licenses contained in the inactive license using the cryptography key of the activation license to store them in the license management database54at step S105. The user apparatus12decrypts the selected encrypted content taken out of the license management database54using a corresponding license to output the decrypted content to the reproduction side at step S6.

FIG. 12is a flowchart of a content distribution processing performed by the server10shown inFIG. 1. InFIG. 2, when the server10determines a package generation request at step S1, it generates a content license including a cryptography key and a permission condition for each plural encrypted contents for a package at step S2. The server10encrypts content licenses generated for respective encrypted contents using the cryptography key included in the activation license and collects them in one file to generate an inactive license at step S3. Next, the server10generates an activation license including the cryptography key used for encryption of content licenses in the inactive license and a permission condition for package sale at step S4. Then, the server10instructs processing of a mobile medium storing the inactive license, such as a CD or DVD, at step S5. The server10checks presence/absence of a purchase request of a package from the user apparatus at step S6, and when it determines a purchase request, it distributes an activation license to the user apparatus after a package sale processing is completed according to accounting utilizing a credit card or the like at step S7. The processing from steps S1to S7is repeated until a stop instruction is issued at step S8.

FIGS. 13A and 13Bare flowcharts of a content utilization processing in the user apparatus10shown inFIG. 2. InFIGS. 13A and 13B, the user apparatus12acquires and reserves the inactive license from such a mobile medium as a DVD at step S1, and it checks selection of reproduction content to form a menu of the package in this state at step S2. When the reproduction content from the package menu is selected, the processing proceeds to step S3, where the user apparatus12checks presence/absence of reservation of an encrypted content corresponding to the selected content. Unless the encrypted content is reserved, the processing proceeds to step S4, where the user apparatus12acquires and reserves the encrypted content. The acquisition of the encrypted content is performed through reading from a mobile medium such as a DVD or a distribution request to the server10. Next, the user apparatus12checks presence/absence of reservation of a license of the selected content at step S5. Unless the license is reserved, the user apparatus12issues a purchase request of an activation license to the server10and reserves the distributed activation license at step S6. Subsequently, the user apparatus12decrypts all the encrypted licenses in the inactive license using the cryptography key of the activation license at step S7and reserves the decrypted licenses in the license management database at step S7. The user apparatus12reads a license of the selected content from the license management database to decrypt a corresponding encrypted content at step S9. The user apparatus12outputs the decrypted content to the player unit to cause the player unit to reproduce the content at step10. Of course, output of the decrypted content to the player unit and reproduction thereof at step S10comply with the permission condition contained in the license read at step S9. When the user apparatus12determines reproduction termination at step S11, it checks presence/absence of a stop instruction at step S12, and the user apparatus12repeats the processing from step S2until it receives the stop instruction.

FIG. 14is a flowchart of details of an encrypted content recovery processing sold as a package at step S9shown inFIGS. 13A and 13B. In the content decryption and reproduction processing, the user apparatus12first reads the inactive license114having the data structure shown inFIG. 8at step S1and displays content information of each element with a content selection menu at step S2. Then, the user apparatus12searches individual element information138-1in the element information132corresponding to a designated element in the inactive license114, for example, the element134-1, at step S3. Then, the user apparatus12designates the encrypted content file name142of the individual element information138-1to acquire a corresponding encrypted content from the content management database48at step S4. Subsequently, the user apparatus12acquires a content license corresponding to the individual element information138-1from the license management database54at step S5. Next, the user apparatus12positions a position in the encrypted content corresponding to a reproduction start position designated by a user as a reference start position of the encrypted content data196in the encrypted content98shown inFIG. 10at step S6, it checks whether or not the reference start position reaches the designated number of bytes at step S7, and it terminates reproduction of the content to branch to RETURN when the reference start position reaches the designated number of bytes. Unless the reference start position reaches the designated number of bytes, the processing proceeds to step S8, where the user apparatus12reads the encrypted block from the reference start position to decrypt it using the cryptography key of the content license and updates positioning of the reference start position. The user apparatus12outputs the data decrypted at step S8to the player unit at step S9and it returns back to checking performed at step S7.

Incidentally, the present invention is not limited to the above embodiment, and it includes proper modification which does not damage the object and the advantage. The present invention is not limited by numeral values shown in the above embodiment.