JP2007088802A - Content transmitter, content transmitting program, content receiver and content receiving program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a content transmitter, a content transmitting program, a content receiver, and a content receiving program which prevents unspecified many receive side apparatuses from freely reproducing encrypted contents. <P>SOLUTION: The content transmitter 1 for sending contents according to a limited reproduction system comprises an encrypted license generating means 5 for generating an encrypted license so that a first content key for encrypting the content, a second key for re-encrypting the received contents once decrypted at the receive side, and information for designating an encrypting key for re-encrypting the decrypted contents at the receive side or domain band control information concerning the method of generating the encrypting key are encrypted by a license encrypting key corresponding to a decrypting key held at the receive side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a content transmission apparatus and a content transmission program for managing and transmitting a right related to content, and a content receiving apparatus and a content reception program for protecting and outputting the right related to the received content.

  Conventionally, in digital broadcasting, a limited playback method is used as one method for realizing access control to broadcast content (also referred to as broadcast program or digital content, hereinafter referred to as content) (see, for example, Patent Document 1).

  In this limited playback method, when content is transmitted, the content is encrypted, and a license for decrypting the encrypted content (encrypted content) (the content creator [broadcast Access to the content by playing the content according to the usage condition information given to the receiving user (right holder who acquired the license) using the contract) Control is realized.

  In the limited reproduction method, content encryption is performed using a content key that is a different encryption key for each content. This content key is included in the license together with the use condition information. In the limited playback method, when the encrypted content is received at the receiving side, if the user does not view the encrypted content immediately, it is stored without being decrypted until it is viewed. Is done.

  When the receiving user views the encrypted content, the receiving device uses the license to decrypt the encrypted content into the content, and then decodes the content. Note that if the content creator (broadcaster) grants a license to the user on the receiving side at the time of playback of the content, even if the encrypted content is stored on the receiving side, It is possible to charge only for the content that has been viewed.

  Further, in the limited playback method, the received encrypted content can be freely copied and moved, but is managed so that the license cannot be copied or moved, thereby protecting the content.

  In addition, in the case of free broadcasting by the limited playback method, the encrypted content and the license are combined and broadcast to all receiving devices at the same time. In this case, the receiving device that receives the broadcast obtains the broadcast encrypted content and the license at the same time. However, the receiving device that has not received the broadcast cannot receive the license as well as the encrypted content.

  As a result, even if the encrypted content is input (copied or moved) from the receiving device that received the broadcast to the receiving device that did not receive the broadcast, it cannot be viewed because there is no license. As a result, encrypted content for free broadcasts using the limited playback method can be retransmitted by securely managing the license so that it cannot be copied or moved even if it is retransmitted from the receiving device that received the broadcast. The use of encrypted content can be controlled, and the right (copyright) related to the content can be protected.

Incidentally, the license is re-encrypted with the unique key held in the security module provided in the device after decrypting the encrypted content when the receiving device receives the broadcast. For this reason, since the unique key is different in the security module provided in the other receiving apparatus, the re-encrypted license cannot be decrypted. In this way, there are means for illegally copying and using the license.
Japanese Patent Laid-Open No. 2003-115832

  However, there is a possibility that a technology that invalidates this means even if the license is illegally copied and used, there is a risk that the technology will be illegally developed. Since the encrypted content received by the receiving device is retransmitted to an unspecified number of devices, it can be freely used by an unspecified number of devices using an illegally copied license. There is a problem of being replayed.

  For example, if the same content key is used for all content without changing the content key included in the license in units of content, the content obtained when any content is received if the license is illegally copied Other content can be played with the key. In other words, in this case, the content key can be obtained if the broadcast encrypted content and the license are received even once. Therefore, if the content that has not been received is obtained by some method, the content key is used. Thus, the content can be used. In this way, when a plurality of encrypted contents can be reproduced with a single license, the requirements (conditions) for protecting the rights (copyright) related to the contents in the retransmission of the received contents are set. You will not be satisfied.

  That is, in pay broadcasting of content by the limited playback method, it is optimal to broadcast (send) content keys in units of content, but when this is applied to free broadcasting, naturally the content is Billing for viewing is no longer the purpose, but the rights to the content, that is, copyright protection is the purpose. For the purpose of copyright protection, if a content key is assigned to each content unit, enormous operational costs are incurred for managing the content key even though it cannot be charged. For these reasons, there is a demand to reduce the operation cost, such as copyright protection and sharing the content key as much as possible.

  Therefore, in the present invention, a content transmission apparatus, a content transmission program, and a content that can solve the above-described problems and prevent the encrypted content from being freely reproduced by an unspecified number of receiving-side apparatuses, and the content It is an object to provide a receiving device and a content receiving program.

  In order to solve the above-described problem, the content transmission apparatus according to claim 1 is configured to include an encrypted license generation unit in the content transmission apparatus that transmits the content by the limited reproduction method.

  According to such a configuration, the content transmitting apparatus re-encrypts the first content key for encrypting the content and the decrypted content obtained by decrypting the encrypted content on the receiving side by the encryption license generating unit. A second content key used for encryption and domain bind control information that is information on the encryption key for re-encrypting the decrypted content on the receiving side or information on the generation method to be generated on the receiving side. An encrypted license encrypted with a license encryption key corresponding to the held decryption key is generated. Then, the content transmission device transmits the generated encrypted license via a broadcast wave or a network.

  According to a second aspect of the present invention, there is provided a content transmission device that transmits content by a limited reproduction method and includes an encrypted license generation unit.

  According to this configuration, the content transmitting apparatus decrypts the first content key for encrypting the scramble key for scrambling the content and the content encrypted by the scramble key on the receiving side by the encryption license generating unit. Domain that is information specifying a second content key used for re-encrypting decrypted decrypted content and an encryption key for re-encrypting decrypted content on the receiving side or a generation method for generating An encrypted license is generated by encrypting the binding control information with a license encryption key corresponding to a decryption key held on the receiving side. Then, the content transmission device transmits the generated encrypted license via a broadcast wave or a network.

  The content transmission apparatus according to claim 3, wherein the encrypted license generation unit is configured with the first content key, the second content key, and the domain bind control information. The output propriety information, which is information relating to the output propriety of the re-encrypted content re-encrypted on the receiving side, is encrypted with the license encryption key.

  According to such a configuration, the content transmission apparatus includes the output permission / prohibition information that is information regarding whether or not the re-encrypted content can be output when the encryption license is generated by the encryption license generation unit. The output permission information specifies whether the re-encrypted content is to be stopped (stored) in the receiving device or output from the receiving device.

  The content transmission device according to claim 4 is the content transmission device according to any one of claims 1 to 3, wherein the encrypted license generation unit includes the first content key, the second content key, and the second content key. Along with the domain bind control information, output count control information that is information relating to control of the output count of the re-encrypted content is encrypted with the license encryption key.

  According to this configuration, the content transmission apparatus includes the output count control information that is information relating to the control of the output count of the re-encrypted content when the encryption license is generated by the encryption license generation unit. In this output count control information, if the output count is set to “0”, it is the same as the state where the output is disabled by the output enable / disable information, and if the output count is set to “1” or more, the output enable / disable information is set. It becomes the same as the state where output is enabled.

  The content transmission device according to claim 5 is the content transmission device according to any one of claims 1 to 4, wherein the first content key and the second content key are equal. .

  According to such a configuration, the content transmission apparatus keeps the first content key and the second content key equal, that is, uses one content key when encrypting the content, and at the receiving side. Thus, it is used when re-encrypting the decrypted content.

  The content transmission device according to claim 6 is the content transmission device according to any one of claims 1 to 5, wherein the domain bind information is an encryption for re-encrypting the decrypted content. Specify the key as the second content key, or generate the re-encrypted content by using the domain key and the second content key, which are common keys held in advance by the group that sends out the re-encrypted content The generation method is described.

  According to such a configuration, the content transmitting apparatus designates the encryption key used when re-encrypting the decrypted content on the receiving side as the second content key or, based on the domain bind information, By describing (determining) the generation method to be generated with the two content keys, as a result, the use range of the re-encrypted re-encrypted content is specified. In other words, when the second content key is specified as the encryption key used for re-encryption, the re-encrypted content usage range is the entire device on the receiving side that received the encryption license, and the domain key and the second key are used. If the generation method to generate with the content key is determined, it is between the receiving side devices holding a common domain key.

  According to a seventh aspect of the present invention, there is provided a content transmission program that causes a computer to function as an encryption license generation unit, an encryption unit, and a multiplexing unit in order to transmit content by a limited reproduction method.

  According to this configuration, the content transmission program re-encrypts the first content key for encrypting the content and the decrypted content obtained by decrypting the encrypted content on the receiving side by the encryption license generation unit. A second content key used for encryption and domain bind control information that is information on the encryption key for re-encrypting the decrypted content on the receiving side or information on the generation method to be generated on the receiving side. An encrypted license encrypted with a license encryption key corresponding to the held decryption key is generated. Then, the content transmission program encrypts the content using the first content key by the encryption unit, and multiplexes and transmits the encrypted content and the encrypted license by the multiplexing unit.

  According to an eighth aspect of the present invention, there is provided a content transmission program that causes a computer to function as an encryption license generation unit, an encryption unit, and a multiplexing unit in order to transmit content by a limited reproduction method.

  According to this configuration, the content transmission program decrypts the first content key for encrypting the scramble key for scrambling the content and the content encrypted by the scramble key on the receiving side by the encryption license generation unit. Domain that is information specifying a second content key used for re-encrypting decrypted decrypted content and an encryption key for re-encrypting decrypted content on the receiving side or a generation method for generating An encrypted license is generated by encrypting the binding control information with a license encryption key corresponding to a decryption key held on the receiving side. Then, the content transmission program encrypts the content using the scramble key by the encryption unit, and multiplexes and transmits the encrypted content and the encrypted license by the multiplexing unit.

  The content receiving apparatus according to claim 9, wherein the content receiving apparatus receives and outputs an encrypted content obtained by encrypting the content and an encrypted license including a first content key used when obtaining the encrypted content. The receiving apparatus is configured to include an encryption license decryption unit, an encrypted content decryption unit, a re-encryption key generation unit, and a re-encryption decryption unit.

  According to such a configuration, the content receiving apparatus decrypts the encrypted license by the encrypted license decryption unit, and decrypts the encrypted content by decrypting the first content key for decrypting the encrypted content. A second content key used for re-encrypting the encrypted content and domain bind control information that is information specifying the encryption key for re-encrypting the decrypted content or information relating to the generation method to be generated are obtained. Subsequently, the content receiving apparatus decrypts the encrypted content by using the first content key obtained by the encrypted license decryption unit by the encrypted content decryption unit to obtain the decrypted content.

  Then, the content reception device uses the re-encryption key generation unit to re-encrypt the re-encrypted content obtained by re-encrypting only the second content key or the second content key and the decrypted content based on the domain binding control information. A re-encryption key used when re-encrypting the decrypted content is generated using a domain key that is a common key held in advance in the group to be transmitted. Then, the content receiving apparatus re-encrypts the decrypted content and re-encrypts the re-encrypted content by using the re-encryption key generated by the re-encryption key generating unit. To do.

  11. A content receiving apparatus according to claim 10, wherein the content receiving apparatus receives and outputs an encrypted content obtained by encrypting the content and an encrypted license including a scramble key used when obtaining the encrypted content. The configuration includes an encrypted license decryption unit, an ECM-Kc decryption unit, an encrypted content decryption unit, a re-encryption key generation unit, and a re-encryption decryption unit.

  According to such a configuration, the content receiving apparatus decrypts the encrypted license by the encrypted license decrypting unit and decrypts the ECM-Kc including the scramble key for scrambling the content, and the encryption Information specifying a second content key used to re-encrypt the decrypted content obtained by decrypting the encrypted content, and an encryption key for re-encrypting the decrypted content, or information relating to a generation method for generating the content key. Get domain bind control information. Subsequently, the content receiving apparatus uses the first content key obtained by the encrypted license decryption unit to use the ECM-Kc obtained by encrypting the scramble key with the first content key by the ECM-Kc decryption unit. Decrypt and obtain a scramble key.

  Then, the content receiving device decrypts the encrypted content by using the scramble key obtained by the ECM-Kc decryption unit by the encrypted content decryption unit, and obtains the decrypted content. Then, the content reception device uses the re-encryption key generation unit to re-encrypt the re-encrypted content obtained by re-encrypting only the second content key or the second content key and the decrypted content based on the domain binding control information. A re-encryption key used when re-encrypting the decrypted content is generated using a domain key that is a common key held in advance in the group to be transmitted. Then, the content receiving apparatus re-encrypts the decrypted content and re-encrypts the re-encrypted content by using the re-encryption key generated by the re-encryption key generating unit. To do.

  12. A content receiving apparatus according to claim 11, wherein the content receiving apparatus receives and outputs an encrypted content obtained by encrypting the content and an encrypted license including a first content key used for obtaining the encrypted content. The receiving device includes an encrypted license decryption unit, an encrypted content decryption unit, a re-encryption key generation unit, and a re-encryption decryption unit, and the re-encryption decryption unit outputs the output permission information. Based on the above, the re-encrypted content is output to the outside.

  According to such a configuration, the content receiving apparatus decrypts the encrypted license by the encrypted license decryption unit, and decrypts the encrypted content by decrypting the first content key for decrypting the encrypted content. Domain binding control information which is information relating to a second content key used for re-encrypting the encrypted content, information specifying a re-encryption key for re-encrypting the decrypted content, or a generation method for generating, Output enable / disable information, which is information related to output enable / disable of re-encrypted content obtained by re-encrypting decrypted content, is obtained. Subsequently, the content receiving apparatus decrypts the encrypted content by using the first content key obtained by the encrypted license decryption unit by the encrypted content decryption unit to obtain the decrypted content.

  Then, the content reception device uses the re-encryption key generation unit to re-encrypt the re-encrypted content obtained by re-encrypting only the second content key or the second content key and the decrypted content based on the domain binding control information. A re-encryption key used when re-encrypting the decrypted content is generated using a domain key that is a common key held in advance in the group to be transmitted. A group that sends re-encrypted content is, for example, a group consisting of several content receiving devices provided in one household, or a group of individuals that are installed at home and at work. It is a group consisting of several content receiving devices. Then, the content receiving apparatus re-encrypts the decrypted content and re-encrypts the re-encrypted content by using the re-encryption key generated by the re-encryption key generating unit. To do. Then, the content receiving apparatus outputs the re-encrypted content to the outside by the re-encryption / decryption unit based on the output permission / inhibition information.

  The content reception device according to claim 12, wherein the content reception apparatus receives and outputs an encrypted content obtained by encrypting the content and an encrypted license including a first content key used when obtaining the encrypted content. The apparatus comprises an encryption license decryption means, an encrypted content decryption means, a re-encryption key generation means, and a re-encryption decryption means, wherein the re-encryption decryption means includes output permission information and The re-encrypted content is output to the outside based on the output count control information.

  According to such a configuration, the content receiving apparatus decrypts the encrypted license by the encrypted license decryption unit, and decrypts the encrypted content by decrypting the first content key for decrypting the encrypted content. Domain binding control information which is information relating to a second content key used for re-encrypting the encrypted content, information specifying a re-encryption key for re-encrypting the decrypted content, or a generation method for generating, Output enable / disable information that is information related to whether or not to output the re-encrypted content obtained by re-encrypting the decrypted content and output count control information that is information related to the control of the output count of the re-encrypted content are obtained. Subsequently, the content receiving apparatus decrypts the encrypted content by using the first content key obtained by the encrypted license decryption unit by the encrypted content decryption unit to obtain the decrypted content.

  Then, the content reception device uses the re-encryption key generation unit to re-encrypt the re-encrypted content obtained by re-encrypting only the second content key or the second content key and the decrypted content based on the domain binding control information. A re-encryption key used when re-encrypting the decrypted content is generated using a domain key that is a common key held in advance in the group to be transmitted. Then, the content receiving apparatus re-encrypts the decrypted content and re-encrypts the re-encrypted content by using the re-encryption key generated by the re-encryption key generating unit. To do. Then, the content receiving apparatus outputs the re-encrypted content to the outside by the re-encryption / decryption unit based on the output permission / inhibition information and the output count control information.

  The content receiving device according to claim 13 is a content receiving device that receives and outputs an encrypted content obtained by encrypting the content and an encrypted license including a scramble key used to obtain the encrypted content. An encryption license decryption unit, an ECM-Kc decryption unit, an encrypted content decryption unit, a re-encryption key generation unit, and a re-encryption decryption unit. However, the re-encrypted content is output to the outside based on output enable / disable information.

  According to such a configuration, the content receiving apparatus decrypts the encrypted license by the encrypted license decrypting unit, and then decrypts the ECM-Kc including the scramble key, and the encrypted content. Is information relating to a second content key used for re-encrypting decrypted decrypted content and a re-encryption key for re-encrypting decrypted content, or information relating to a generation method for generating the content key. The domain binding control information and the output permission information that is information regarding whether to output the re-encrypted content obtained by re-encrypting the decrypted content are obtained. Subsequently, the content receiving apparatus uses the first content key obtained by the encrypted license decryption means to use the ECM-Kc obtained by encrypting the scramble key with the first content key by the ECM-Kc decryption means. Decrypt and obtain a scramble key.

  Then, the content receiving device decrypts the encrypted content by using the scramble key obtained by the ECM-Kc decryption unit by the encrypted content decryption unit, and obtains the decrypted content. Then, the content reception device uses the re-encryption key generation unit to re-encrypt the re-encrypted content obtained by re-encrypting only the second content key or the second content key and the decrypted content based on the domain binding control information. A re-encryption key used when re-encrypting the decrypted content is generated using a domain key that is a common key held in advance in the group to be transmitted. Then, the content receiving apparatus re-encrypts the decrypted content and re-encrypts the re-encrypted content by using the re-encryption key generated by the re-encryption key generating unit. To do. Then, the content receiving apparatus outputs the re-encrypted content to the outside by the re-encryption / decryption unit based on the output permission / inhibition information.

  The content receiving device according to claim 14 is a content receiving device that receives and outputs an encrypted content obtained by encrypting the content and an encrypted license including a scramble key used to obtain the encrypted content. An encryption license decryption unit, an ECM-Kc decryption unit, an encrypted content decryption unit, a re-encryption key generation unit, and a re-encryption decryption unit. However, the re-encrypted content is output to the outside based on the output permission information and the output count control information.

  According to such a configuration, the content receiving apparatus decrypts the encrypted license by the encrypted license decrypting unit, and then decrypts the ECM-Kc including the scramble key, and the encrypted content. Is information relating to a second content key used for re-encrypting decrypted decrypted content and a re-encryption key for re-encrypting decrypted content, or information relating to a generation method for generating the content key. Domain binding control information, output permission information that is information regarding whether or not to output re-encrypted content obtained by re-encrypting decrypted content, and output number control information that is information regarding control of the number of times that re-encrypted content is output obtain. Subsequently, the content receiving apparatus decrypts the ECM-Kc encrypted with the first content key by the ECM-Kc decrypting unit using the first content key obtained by the encrypted license decrypting unit, Get a scramble key.

  Then, the content receiving device decrypts the encrypted content by using the scramble key obtained by the ECM-Kc decryption unit by the encrypted content decryption unit, and obtains the decrypted content. Then, the content reception device uses the re-encryption key generation unit to re-encrypt the re-encrypted content obtained by re-encrypting only the second content key or the second content key and the decrypted content based on the domain binding control information. A re-encryption key used when re-encrypting the decrypted content is generated using a domain key that is a common key held in advance in the group to be sent. Then, the content receiving apparatus re-encrypts the decrypted content and re-encrypts the re-encrypted content by using the re-encryption key generated by the re-encryption key generating unit. To do. Then, the content receiving apparatus outputs the re-encrypted content to the outside by the re-encryption / decryption unit based on the output permission / inhibition information and the output count control information.

  The content receiving program according to claim 15 is for receiving and outputting an encrypted content obtained by encrypting the content and an encrypted license including a first content key used for obtaining the encrypted content. In addition, the computer is configured to function as an encryption license decryption unit, an encrypted content decryption unit, a reencryption key generation unit, and a reencryption decryption unit.

  According to such a configuration, the content reception program decrypts the encrypted license by the encrypted license decryption unit, and the decryption in which the encrypted content is decrypted and the first content key for decrypting the encrypted content. A second content key used for re-encrypting the encrypted content, and domain bind control information that is information specifying a re-encryption key for re-encrypting the decrypted content or information relating to a generation method to be generated obtain. Subsequently, the content receiving program decrypts the encrypted content by using the first content key obtained by the encrypted license decryption unit by the encrypted content decryption unit to obtain the decrypted content. Then, the content receiving program uses the re-encryption key generation unit to re-encrypt the re-encrypted content obtained by re-encrypting only the second content key or the second content key and the decrypted content based on the domain binding control information. Generate a re-encryption key to be used when re-encrypting decrypted content using a domain key that is a common key held in advance by the sending group, and generate a re-encryption key by the re-encryption / decryption means Using the re-encryption key generated by the means, the decrypted content is re-encrypted and the re-encrypted content is decrypted.

  In order to receive and output an encrypted content obtained by encrypting content and an encrypted license including a scramble key used when obtaining the encrypted content, the content receiving program according to claim 16 The computer is configured to function as an encryption license decryption unit, an ECM-Kc decryption unit, an encrypted content decryption unit, a reencryption key generation unit, and a reencryption decryption unit.

  According to such a configuration, the content reception program decrypts the encrypted license by the encrypted license decryption unit, and the encrypted content decrypts the first content key for decrypting the ECM-Kc including the scramble key. Domain binding that is information specifying the second content key used to re-encrypt the decrypted content and the re-encryption key for re-encrypting the decrypted content, or information on the generation method to be generated Control information. Subsequently, the content receiving program decrypts the ECM-Kc encrypted with the first content key by the ECM-Kc decrypting unit using the first content key obtained by the encrypted license decrypting unit, Get a scramble key. Then, the content receiving program decrypts the encrypted content by using the scramble key obtained by the ECM-Kc decrypting unit by the encrypted content decrypting unit, thereby obtaining the decrypted content. Then, the content receiving program uses the re-encryption key generation unit to re-encrypt the re-encrypted content obtained by re-encrypting only the second content key or the second content key and the decrypted content based on the domain binding control information. Generate a re-encryption key to be used when re-encrypting decrypted content using a domain key that is a common key held in advance by the sending group, and generate a re-encryption key by the re-encryption / decryption means Using the re-encryption key generated by the means, the decrypted content is re-encrypted and the re-encrypted content is decrypted.

  According to the first, second, seventh, and eighth aspects of the present invention, the decrypted content obtained by decrypting the encrypted content is re-encrypted on the receiving side in accordance with the domain binding control information included in the generated encrypted license. Therefore, it is possible to prevent the encrypted content from being freely reproduced by an unspecified number of receiving devices.

  According to the third aspect of the present invention, since whether or not to output the re-encrypted content is controlled according to the output availability information on the receiving side, the encrypted content can be freely reproduced by an unspecified number of receiving-side devices. Can be prevented.

  According to the fourth aspect of the present invention, the number of times of output of the re-encrypted content is controlled on the receiving side according to the output number control information. It can be prevented from being reproduced.

  According to the fifth aspect of the invention, the information to be transmitted can be reduced by making the first content key and the second content key equal.

  According to the sixth aspect of the present invention, the re-encryption key used on the receiving side is designated as the second content key or generated with the second content key and the domain key based on the domain binding control information. You can decide what to do.

  According to the inventions described in claims 9, 10, 15, and 16, since the decrypted content obtained by decrypting the encrypted content is re-encrypted according to the domain binding control information set on the transmission side, It is possible to prevent the encrypted content from being freely played by the receiving device.

  According to the inventions described in claims 11 and 13, since whether or not to output the re-encrypted content is controlled according to the output enable / disable information set on the transmission side, the encrypted content can be freely selected by an unspecified number of receiving-side devices. Can be prevented from being reproduced.

  According to the invention described in claims 12 and 14, since the number of output times of the re-encrypted content is controlled according to the output number control information set on the transmission side, it can be freely encrypted by an unspecified number of receiving-side devices. It is possible to prevent the content from being reproduced.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
<Configuration of Content Transmission Device [First Embodiment]>
FIG. 1 is a block diagram of a content transmission apparatus (first embodiment). As shown in FIG. 1, a content transmitting apparatus 1 transmits content by a limited playback method, that is, encrypted content or scrambled content (hereinafter, both are referred to as encrypted content). And an encryption license generating means 5, a multiplexing means 7, and a communication processing means 9.

  The encryption unit 3 encrypts the input content using the first content key Kc1. The contents refer to video / audio contents, multimedia contents described in BML (Broadcast Markup Language), Java (registered trademark), and the like. The first content key Kc1 is an encryption key for encrypting content, and is set for each content. The encryption of content by the encryption means 3 uses an encryption algorithm such as AES (Advanced Encryption Standard) or DES (Data Encryption Standard).

  The encrypted license generation means 5 receives the input first content key Kc1, second content key Kc2, domain bind control information, re-encrypted content output permission / inhibition information, and re-encrypted content output count control information as license encryption. An encryption license encrypted using a key is generated.

The second content key Kc2 is an encryption key used when the decrypted content obtained by decrypting the encrypted content is re-encrypted in the content receiving device 11 (see FIG. 2) on the receiving side.
The domain bind control information is information specifying a re-encryption key used for re-encrypting encrypted content transmitted by a broadcaster (content producer) on the transmission side or information on a generation method for generating the information. It is.

The output permission information is obtained by re-encrypting the encrypted content transmitted by the broadcaster (content creator) on the transmission side, and from the content reception device 11 on the reception side to an external device or a removable medium (for example, DVD, USB memory). Information for controlling writing to a storage device such as (information on whether output is possible).
The output count control information is the number of times the encrypted content transmitted by the broadcaster (content creator) on the transmission side is re-encrypted and written from the content reception device 11 on the reception side to an external device or a storage device such as removable media. This is information (information related to the number of outputs) for controlling.
The license encryption key is an encryption key corresponding to the decryption key (license decryption key) held in the content receiving device 11 on the receiving side.

  The multiplexing means 7 sends the multiplexed content obtained by multiplexing the encrypted content obtained by encrypting the content by the encrypting means 3 and the encrypted license generated by the encrypted license generating means 5 to the receiving apparatus. To be sent. The multiplexed content multiplexed by the multiplexing means 7 is in the form of one stream such as MPEG-2 TS (Transport Stream), and this multiplexed content can be transmitted to a broadcast wave or a communication network. (Via a communication network).

  The communication processing unit 9 transmits the encrypted license generated by the encrypted license generating unit 5 to the content receiving apparatus 11 on the receiving side via a communication line network (communication network). In this communication processing means 9, the encrypted content is not transmitted, and only the encrypted license is sent at the same time as the encrypted content or before (before transmitting the encrypted content) or after (after transmitting the encrypted content). Sending. The communication processing means 9 employs a protocol such as TCP / IP. When the encrypted license is transmitted by the communication processing unit 9, the multiplexing unit 7 can transmit only the encrypted content without multiplexing the encrypted content and the encrypted license.

  According to the content transmitting apparatus 1, since the decrypted content obtained by decrypting the encrypted content is re-encrypted according to the domain bind control information in the content receiving apparatus 11 on the receiving side, an unspecified number of receiving sides It is possible to prevent the encrypted content from being freely played on the device.

<Configuration of content receiving apparatus [first embodiment]>
FIG. 2 is a block diagram of the content receiving apparatus (first embodiment). As shown in FIG. 2, the content receiving apparatus 11 receives the multiplexed content or the encrypted content and the encrypted license transmitted from the transmission side, decrypts the encrypted content, and then decodes the decrypted content. Output. Alternatively, the content receiving apparatus 11 outputs re-encrypted content obtained by re-encrypting the decrypted content obtained by decrypting the encrypted content. The content receiving device 11 is configured to output the separation unit 13, the communication processing unit 15, the security module 17, and the encryption module. Encrypted content decrypting means 19, re-encrypting / decrypting means 21, decoding means 23, storage means 25, and external input / output means 27. Note that the security module 17 is detachable from the content receiving apparatus 11, but is indispensable when the apparatus 11 operates. For this reason, it is handled integrally with the apparatus 11 here.

  The separating means 13 receives the multiplexed content transmitted from the content transmission apparatus 1 on the transmission side (see FIG. 1) and separates it into the encrypted content and the encrypted license. In this separation means 13, when the multiplexed content is a TS encoded by MPEG-2, it is separated into the encrypted content and the encrypted license by filtering using the PID in the header of the TS packet. ing. The encrypted content separated by the separation means 13 is output to the encrypted content decryption means 19, and the encrypted license is output to the security module 17.

  The communication processing means 15 receives the encrypted license transmitted from the transmission side via the communication line network (communication network), and outputs the received encrypted license to the security module 17. If the encrypted license is processed by the security module 17 and is determined to be invalid because the license has expired, it is returned from the security module 17 to the communication processing means 15. The result (invalid) processed from the communication processing means 15 to the transmission side is returned to the apparatus 11.

  The security module 17 is a module having tamper resistance, such as an IC card, which processes the input encryption license. The security license decryption means 29, the control information processing means 31, and the re-encryption And an encryption key generation means 33.

  The encrypted license decryption means 29 decrypts the input encrypted license using the license decryption key when decrypting the encrypted content, and the first content key Kc1, the second content key Kc2, the domain bind A license (decryption license) including control information, output permission / inhibition information, and output count control information is obtained and output to the control information processing means 31, and a license holding means 29a is provided.

  When the encrypted content is not decrypted, the license retaining unit 29a retains the input encrypted license without decrypting it. The reason why the encrypted license is retained without being decrypted is to prepare for the case where the received encrypted content is temporarily stored and then decrypted and viewed. In other words, in the limited playback system, the encrypted content is stored in an encrypted state, and is used to decrypt the encrypted content until the receiving viewer decides to view the encrypted content. The first content key Kc1 is also kept encrypted.

  When the license is obtained by the encrypted license decryption means 29, the control information processing means 31 reads and processes various information from the license. Here, a license format (data structure) will be described with reference to FIG.

The license is a license identification that is an ID for identifying the license, a protocol number that is a number for identifying a protocol, an entity identification that is an ID for identifying a broadcaster, and a license decryption key identification that is an ID for identifying a license decryption key First content key identification which is an ID for identifying the first content key Kc1, first content key Kc1, a valid period indicating a period during which the license is valid, and a second content which is an ID for identifying the second content key Kc2. It includes key identification, second content key Kc2, domain binding control information, re-encrypted content output permission information, and re-encrypted content output count control information.
Returning to FIG. 2, the description of the configuration of the content receiving apparatus 11 will be continued.

  The control information processing means 31 first determines whether or not the license is valid (whether or not it is within the valid period) by looking at the validity period of the license input from the encrypted license decryption means 29. ) If the license is valid, the first content key Kc 1 is output to the encrypted content decryption unit 19 and the second content key Kc 2 is output to the re-encryption key generation unit 33. If the license is not valid, the first content key Kc1 is not output to the encrypted content decryption means 19 and the second content key Kc2 is not output to the re-encryption key generation means 33. In this case, the fact that the license is not valid is displayed on the display device (not shown) via the encrypted content decrypting means 19 and the decoding means 23.

  The re-encryption key generating unit 33 is used when re-encrypting the decrypted content decrypted by the encrypted content decrypting unit 19 based on the domain binding control information output from the control information processing unit 31. A re-encryption key Kr is generated.

  For example, when the second content key Kc2 is designated as the re-encryption key Kr in the domain bind control information (the domain bind control information is “No”, that is, when the domain key is not used), the re-encryption is performed. The encryption key generation unit 33 outputs the second content key Kc2 to the re-encryption / decryption unit 21. In addition, when the generation method for generating the re-encryption key Kr is described in the domain binding control information (when the domain binding control information is “Yes”, that is, when the domain key is used), this generation method includes Along with this, a re-encryption key Kr is generated.

  As an example, a hash value obtained through a hash function may be used as the re-encryption key Kr for a value obtained by combining the domain key and the second content key Kc2 held in advance in the security module 17.

  The domain key is information for grouping the content receiving apparatuses 11. For example, when content receivers 11 existing in different locations are to be in the same group, the domain key in the security module 17 attached to each content receiver 11 is set to the same value and held. To do. That is, the content receiving apparatuses 11 belonging to the same group hold a common domain key in the security module 17 to be attached.

  For example, when a plurality of content receiving devices 11 are provided in the home, the domains in the security module 17 provided in each of the content receiving devices 11 to group these content receiving devices 11 together. Set the key in common. The domain key is transmitted by a business operator (for example, a broadcast business operator) that manages the security module 17 via a broadcast or communication network. It is necessary to make a contract with the operator in advance so that a common domain key is set.

  The encrypted content decryption means 19 decrypts the encrypted content separated by the separation means 13 with the first content key Kc1 output from the control information processing means 31 of the security module 17, and decrypts the decrypted content ( Plaintext content) is output to the re-encryption / decryption means 21 and the decoding means 23.

  The re-encryption / decryption means 21 re-encrypts the decrypted content decrypted by the encrypted content decryption means 19 with the re-encryption key Kr output from the security module 17, or the storage means 25 or The re-encrypted content output from the external input / output means 27 is decrypted. Then, the re-encryption / decryption unit 21 outputs the re-encrypted content to the storage unit 25 or the external input / output unit 27, and decrypts the re-encrypted content (plaintext content) obtained by decrypting the re-encrypted content. , Output to the decoding means 23. The re-encryption / decryption means 21 is configured to re-encrypt if the input is decrypted content, and to decrypt if the input is re-encrypted content. .

  The decoding means 23 decodes the decrypted content or the decrypted and re-encrypted content (both plaintext content) into a baseband signal and outputs it to a display device (not shown). The decoding means 23 corresponds to an MPEG-2 decoder or a BML browser.

  The storage unit 25 stores the re-encrypted content re-encrypted by the re-encryption / decryption unit 21. The storage unit 25 is a recording medium such as a hard disk drive built in the apparatus 11 or a reambal medium such as an optical disk. It is constituted by.

  The external input / output unit 27 outputs the re-encrypted content re-encrypted by the re-encryption / decryption unit 21 to the outside of the device 11. Alternatively, the external input / output unit 27 outputs re-encrypted content input from outside the device 11 to the re-encryption / decryption unit 21. The external input / output means 27 corresponds to an interface such as an IEEE 1394 interface or Ethernet (registered trademark).

  According to the content receiving apparatus 11, the re-encryption key Kr for re-encrypting the decrypted content obtained by decrypting the encrypted content is output in accordance with the domain binding control information set on the transmission side. Since the output of the re-encrypted content is controlled according to the number control information, it is possible to prevent the encrypted content from being freely reproduced by an unspecified number of receiving-side devices.

  That is, in the content receiving device 11, re-encrypted content stored in the storage unit 25 or re-encrypted content stored in an external storage device (not shown) connected to the external input / output unit 27 is temporarily invalid. Even if it is distributed to a large number of unspecified receiving devices (other content receiving devices 11), other content receiving devices 11 having security modules 17 having different domain keys or other licenses are not owned. The content receiving device 11 cannot reproduce the re-encrypted content.

  In the content receiving device 11, when re-encrypted content is exchanged between other content receiving devices 11 having security modules 17 having different domain keys, the re-encrypted content is stored even if the license is owned. Can't play. That is, the range in which the encrypted content included in the multiplexed content received by the content receiving device 11 can be retransmitted can be limited to the content receiving device 11 grouped by the domain key. The content receiving apparatus 11 having the security module 17 having a common domain key can reproduce the re-encrypted content if the license is obtained, and share the encrypted content included in the received multiplexed content. And can be used.

  When a group of content receiving apparatuses 11 capable of reproducing re-encrypted content is grouped with a domain key, if the content receiving apparatus 11 is equipped with a GPS, it is within the range specified by the GPS. A group of a plurality of content receiving apparatuses 11 can be formed. In addition, when the content receiving device 11 is configured as a portable terminal (for example, a mobile phone), several content receiving devices 11 (including portable terminals) used by a certain person at home and at work. It is also possible to form a group.

  Therefore, even if the content receiving device 11 retransmits the re-encrypted content obtained by re-encrypting the encrypted content included in the received multiplexed content to the other unspecified number of other content receiving devices 11. The other content receiving apparatus 11 has no meaning because it cannot be played back unless the domain key is common and the license is obtained, and as a result, re-transmission can be prevented, so that the re-encrypted content can be stored safely. 25, and can be safely output to an external storage device (not shown) connected to the external input / output means 27.

  Note that when the re-encrypted content is stored in the storage unit 25 of the content receiving device 11 or when the re-encrypted content is externally output from the content receiving device 11, the output permission information and the output count control information are followed. For example, if “impossible” is described in the output enable / disable information, it cannot be output to the outside, and if it is described twice in the output count control information, the re-encrypted content is stored in the storage means 25 or External output is possible via the external input / output means 27.

<Operation of Content Transmission Device [First Embodiment]>
Next, the operation of the content transmission apparatus 1 will be described with reference to the flowchart shown in FIG. 3 (see FIG. 1 as appropriate).
First, the content transmitting apparatus 1 encrypts the input content with the first content key Kc1 by the encryption unit 3 (step S1). Subsequently, the content transmitting apparatus 1 encrypts the first content key Kc1, the second content key Kc2, the domain bind control information, the output permission information, and the output count control information with the license key by the encrypted license generation unit 5. An encrypted license is generated (step S2).

  Then, the content transmitting apparatus 1 multiplexes the encrypted content output from the encrypting unit 3 and the encrypted license output from the encrypted license generating unit 5 by the multiplexing unit 7 and transmits the multiplexed content. (Step S3). Note that the content transmission apparatus 1 operates the operation means (not shown) by the user of the apparatus 1 and specifies that the encrypted content and the encrypted license are to be transmitted separately, whereby the encrypted license is transmitted. May be transmitted by the communication processing means 9 without being multiplexed by the multiplexing means 7.

<Operation of content receiving apparatus [first embodiment]>
Next, the operation of the content receiving apparatus 11 will be described with reference to the flowchart shown in FIG. 4 (see FIG. 2 as appropriate).
First, the content receiving apparatus 11 receives the multiplexed content by the separating means 13 and separates the multiplexed content into the encrypted content and the encrypted license (step S11). Subsequently, the content receiving apparatus 11 inputs the encrypted license to the security module 17, and the encrypted license decrypting unit 29 decrypts the encrypted license using the license decryption key (step S12).

  Then, the content receiving apparatus 11 outputs the first content key Kc1 extracted from the license decrypted by the encrypted license decrypting means 29 by the control information processing means 31 to the encrypted content decrypting means 19 (step) S13). Then, the content receiving apparatus 11 decrypts the encrypted content by using the first content key Kc1 by the encrypted content decrypting means 19 (step S14). The decrypted decrypted content is displayed on a display device (not shown) by the decoding means 23.

  Further, the content receiving apparatus 11 generates the re-encryption key Kr by the re-encryption key generation unit 33 based on the domain binding control information (step S15), and re-encrypts by the re-encryption / decryption unit 21. Using the key Kr, the decrypted content is re-encrypted (step S16). Then, the content receiving apparatus 11 stores the re-encrypted content in the storage unit 25 and outputs the re-encrypted content to the outside by the external input / output unit 27 based on the output permission information and the output count control information. (Step S17).

<Configuration of Content Transmission Device [Second Embodiment]>
FIG. 5 is a block diagram of the content transmission apparatus (second embodiment). As shown in FIG. 5, the content transmitting apparatus 1A transmits content by the limited reproduction method. The content transmitting apparatus 1A includes an encryption unit 3a, an encrypted license generation unit 5, a multiplexing unit 7a, and a communication processing unit 9. ECM-Kc generating means 35. In addition, about the structure similar to the content transmission apparatus 1 shown in FIG. 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The encryption unit 3a scrambles the input content with the scramble key Ks. The scramble key Ks is an encryption key that is changed in about several seconds. This content transmitting apparatus 1A handles scramble key Ks that is changed in about several seconds, that is, encrypted content that is encrypted with a plurality of encryption keys.

  The ECM-Kc generation means 35 encrypts the scramble key Ks using the first content key Kc1 and generates ECM-Kc defined in ARIB STD-25 “Access Control Method in Digital Broadcasting”. . The ECM-Kc generated by the ECM-Kc generation unit 35 is output to the multiplexing unit 7a.

  The multiplexing unit 7a multiplexes the encrypted content scrambled by the encryption unit 3a, the ECM-Kc generated by the ECM-Kc generation unit 35, and the encryption license generated by the encryption license generation unit 5. The multiplexed content is transmitted to the receiving device.

  According to the content transmitting apparatus 1A, the decrypted content obtained by decrypting the encrypted content is re-encrypted in the receiving apparatus according to the domain bind control information. It is possible to prevent the encrypted content from being freely reproduced.

<Configuration of content receiving apparatus [second embodiment]>
FIG. 6 is a block diagram of the content receiving apparatus (second embodiment). As shown in FIG. 6, the content receiving apparatus 11A receives the multiplexed content or the encrypted content and the encrypted license transmitted from the transmission side, and decrypts and decodes the encrypted content, or outputs them. The re-encrypted content obtained by re-encrypting the decrypted content obtained by decrypting the encrypted content is output. The separating unit 13a, the communication processing unit 15, the security module 17a, the encrypted content decrypting unit 19a, Re-encryption / decryption means 21, decoding means 23, storage means 25, and external input / output means 27 are provided. The security module 17a is detachable from the content receiving apparatus 11A. However, since the security module 17a is required to be attached when the apparatus 11A operates, the security module 17a is handled integrally with the apparatus 11A. ing. In addition, about the structure similar to the content receiver 11 shown in FIG. 2, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The separating means 13a receives the multiplexed content transmitted from the transmitting device (content transmitting device 1A) and separates it into the encrypted content, ECM-Kc, and encrypted license. In the separation means 13a, when the multiplexed content is an MPEG-2 TS, it is separated into the encrypted content, the ECM-Kc, and the encrypted license by filtering using the PID in the header of the TS packet. ing. The encrypted content separated by the separation means 13a is output to the encrypted content decryption means 19a, and the ECM-Kc and the encrypted license are output to the security module 17a.

  The security module 17a is a module having tamper resistance, such as an IC card, which processes the input ECM-Kc and the encryption license. The security license decryption means 29 and the control information processing means 31 are processed. And a re-encryption key generation unit 33 and an ECM-Kc decryption unit 37. In addition, about the structure similar to the security module 17 of the content receiver 11 shown in FIG. 2, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The ECM-Kc decryption unit 37 decrypts the ECM-Kc using the first content key Kc1 output from the control information processing unit 31, and decrypts the scramble key Ks extracted from the decrypted ECM-Kc. Is output to the converting means 19a. When the control information processing unit 31 outputs the first content key Kc1, the validity period included in the decrypted license (license) obtained by decrypting the encrypted license by the encrypted license decrypting unit 29 is If it has passed, the first content key Kc1 is not output to the ECM-Kc decrypting means 37, and the ECM-Kc is not decrypted. Further, the fact that the license is invalid (expired in validity) is displayed on a display device (not shown).

  The encrypted content decryption means 19a is for decrypting the encrypted content using the scramble key Ks output from the ECM-Kc decryption means 37 of the security module 17a. The decrypted content (plaintext content) decrypted by the encrypted content decryption means 19 a is output to the decoding means 23 and the re-encryption decryption means 21.

  According to this content receiving apparatus 11A, the re-encryption key Kr for re-encrypting the decrypted content obtained by decrypting the encrypted content is output in accordance with the domain binding control information set on the transmission side, the output permission information, the output Since the output of the re-encrypted content is controlled according to the number control information, it is possible to prevent the encrypted content from being freely reproduced by an unspecified number of receiving-side devices.

<Configuration of content receiving apparatus [third embodiment]>
FIG. 7 is a block diagram of the content receiving apparatus (third embodiment). As shown in FIG. 7, the content receiving apparatus 11B receives the multiplexed content or the encrypted content and the encrypted license transmitted from the transmission side, and decrypts and decodes the encrypted content for output. A re-encrypted content obtained by re-encrypting the decrypted content obtained by decrypting the encrypted content or a re-multiplexed content obtained by multiplexing the encrypted content and the re-encrypted ECM-Kc obtained by re-encrypting the ECM-Kc is output. The separating means 13a, the communication processing means 15, the security module 17b, the encrypted content decrypting means 19a, the decoding means 23, the storage means 25, the external input / output means 27, the multiplexing means 41, It has. Although the security module 17b is detachable from the content receiving apparatus 11B, it is essential to be attached when the apparatus 11B operates, and therefore, here, the security module 17b is handled integrally with the apparatus 11B. ing. In addition, about the structure similar to 11 A of content receivers shown in FIG. 6, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In this content receiving device 11B, after decrypting the encrypted content scrambled with a plurality of scramble keys Ks, the content is displayed on the display device (not shown) by the decoding means 23 and the encrypted content is decrypted. The re-multiplexed content obtained by re-multiplexing the encrypted content and the re-encrypted ECM-Kc re-encrypted by the security module 17b is output.

  The security module 17b is a module having tamper resistance, such as an IC card, which processes the input ECM-Kc and the encryption license. The security module 17b is an encryption license decryption unit 29 and a control information processing unit 31. A re-encryption key generation unit 33, an ECM-Kc decryption unit 37, and an ECM-Kc generation unit 39. In addition, about the structure similar to the security module 17a of 11 A of content receivers shown in FIG. 6, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The ECM-Kc generation unit 39 re-encrypts the scramble key Ks output from the ECM-Kc decryption unit 37 using the re-encryption key Kr generated by the re-encryption key generation unit 33. ECM-Kc is generated. The re-encrypted ECM-Kc generated by the ECM-Kc generation unit 39 is output to the multiplexing unit 41.

  The multiplexing means 41 stores the re-multiplexed content obtained by multiplexing the encrypted content output from the separating means 13a and the re-encrypted ECM-Kc output from the ECM-Kc generating means 39 of the security module 17b. This is output to the means 25 and the external input / output means 27.

  According to the content receiving apparatus 11B, after decrypting the ECM-Kc, the re-encrypted ECM-Kc is generated by the re-encryption key Kr generated according to the domain binding control information, and the re-encrypted ECM-Kc. Since the output of the re-multiplexed content obtained by re-multiplexing the encrypted content and the encrypted content is controlled according to the output permission information and the output count control information, the encrypted content can be freely played back by an unspecified number of receiving devices. Can be prevented.

  For example, if the encrypted content handled by the content receiving apparatus 11B is scrambled video / audio content, the data amount per hour of the video / audio content increases to about 10 Gbytes. It takes a long time for the conversion process. Therefore, the content receiving apparatus 11B reduces the processing load only by re-encrypting the ECM-Kc of about several tens of bytes using the first content key Kc1.

<Operation of Content Transmission Device [Second Embodiment]>
Next, the operation of the content transmission device 1A will be described with reference to the flowchart shown in FIG. 8 (see FIG. 5 as appropriate).
First, the content transmitting apparatus 1A scrambles the input content with the scramble key Ks by the encryption means 3 (step S21). Subsequently, the content transmitting apparatus 1A generates an ECM-Kc obtained by encrypting the scramble key Ks using the first content key Kc1 by the ECM-Kc generating unit 35 (step S22).

  Then, the content transmitting apparatus 1A uses the encrypted license generating means 5 to encrypt the first content key Kc1, the second content key Kc2, the domain bind control information, the output permission information, and the output count control information with the license key. A license is generated (step S23).

  Then, the content transmitting apparatus 1A outputs the encrypted content output from the encrypting unit 3, the ECM-Kc output from the ECM-Kc generating unit 35, and the encrypted license generating unit 5 by the multiplexing unit 7a. The obtained encrypted license is multiplexed and transmitted as multiplexed content (step S24). The content transmitting apparatus 1A may transmit the encrypted license by the communication processing unit 9 without multiplexing by the multiplexing unit 7a.

<Operation of Content Receiving Device [Second Embodiment]>
Next, the operation of the content receiving apparatus 11A will be described with reference to the flowchart shown in FIG. 9 (see FIG. 6 as appropriate).
First, the content receiving apparatus 11A receives the multiplexed content by the separating unit 13a, and separates the multiplexed content into the encrypted content, the ECM-Kc, and the encrypted license (step S31). Subsequently, the content receiving apparatus 11A inputs the ECM-Kc and the encrypted license to the security module 17a, and the encrypted license decryption unit 29 decrypts the encrypted license using the license decryption key (step S32). ).

  Then, the content receiving apparatus 11A outputs the first content key Kc1 extracted from the license decrypted by the encrypted license decryption unit 29 to the ECM-Kc decryption unit 37 by the control information processing unit 31 (step S31). S33) The ECM-Kc decrypting means 37 decrypts the ECM-Kc using the first content key Kc1 (step S34).

  Then, the content receiving device 11A outputs the scramble key Ks to the encrypted content decryption unit 19a by the ECM-Kc decryption unit 37 (step S35), and uses the scramble key Ks by the encrypted content decryption unit 19a. Then, the encrypted content is decrypted (step S36). The decrypted decrypted content is displayed on a display device (not shown) by the decoding means 23.

  Further, the content receiving apparatus 11A generates the re-encryption key Kr based on the domain binding control information by the re-encryption key generation unit 33 (step S37), and re-encrypts by the re-encryption / decryption unit 21. The decrypted content is re-encrypted using the key Kr (step S38). Then, the content receiving apparatus 11A stores the re-encrypted content in the storage unit 25 and outputs the re-encrypted content to the outside by the external input / output unit 27 based on the output permission information and the output count control information. (Step S39).

<Operation of content receiving apparatus [third embodiment]>
Next, the operation of the content receiving apparatus 11A will be described with reference to the flowchart shown in FIG. 10 (see FIG. 7 as appropriate).
First, the content receiving device 11B receives the multiplexed content by the separating unit 13a, and separates the multiplexed content into the encrypted content, the ECM-Kc, and the encrypted license (step S41). Subsequently, the content receiving apparatus 11B inputs the ECM-Kc and the encrypted license to the security module 17b, and the encrypted license decrypting unit 29 decrypts the encrypted license using the license decryption key (step S42). ).

  Then, the content receiving apparatus 11B outputs the first content key Kc1 extracted from the license decrypted by the encrypted license decryption means 29 by the control information processing means 31 to the ECM-Kc decryption means 37 (step S43) The ECM-Kc decrypting means 37 decrypts the ECM-Kc by using the first content key Kc1 (step S44).

  Then, the content receiving apparatus 11B outputs the scramble key Ks to the encrypted content decryption unit 19a by the ECM-Kc decryption unit 37 (step S45), and uses the scramble key Ks by the encrypted content decryption unit 19a. Thus, the encrypted content is decrypted (step S46). The decrypted decrypted content is displayed on a display device (not shown) by the decoding means 23.

  Further, the content receiving apparatus 11B generates the re-encryption key Kr by the re-encryption key generation unit 33 based on the domain binding control information (step S47), and the ECM-Kc generation unit 39 generates the re-encryption key. Using Kr, re-encrypted ECM-Kc is generated by re-encrypting the scramble key Ks (step S48). Then, the content receiving apparatus 11B multiplexes the encrypted content output from the separating unit 13a and the re-encrypted ECM-Kc output from the ECM-Kc generating unit 39 by the multiplexing unit 41, and re-multiplexes them. As the content, the re-multiplexed content is stored in the storage unit 25, and the re-encrypted content is output to the outside by the external input / output unit 27 based on the output permission information and the output count control information (step S49). .

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. For example, in the present embodiment, the content transmission devices 1 and 1A and the content reception devices 11, 11A, and 11B are configured. However, a general-purpose or special-purpose computer can be used as long as the processing of each configuration of these devices can be realized. It is also possible to configure as a content transmission program and a content reception program described in a language. In these cases, the same effects as those of the content transmission devices 1 and 1A and the content reception devices 11, 11A, and 11B can be obtained.

1 is a block diagram of a content transmission device (first embodiment) according to an embodiment of the present invention. 1 is a block diagram of a content receiving device (first embodiment) according to an embodiment of the present invention. 3 is a flowchart for explaining the operation of the content transmission device (first embodiment) shown in FIG. 1. It is a flowchart for demonstrating operation | movement of the content receiver (1st embodiment) shown in FIG. It is a block diagram of the content transmission apparatus (2nd embodiment) which concerns on embodiment of this invention. It is a block diagram of the content receiver (2nd embodiment) which concerns on embodiment of this invention. It is a block diagram of the content receiver (3rd embodiment) which concerns on embodiment of this invention. It is a flowchart for demonstrating operation | movement of the content transmission apparatus (2nd embodiment) shown in FIG. It is a flowchart for demonstrating operation | movement of the content receiver (2nd embodiment) shown in FIG. It is a flowchart for demonstrating operation | movement of the content receiver (3rd embodiment) shown in FIG. It is a figure for demonstrating the data structure of a license.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A Content transmission apparatus 3 Encryption means 5 Encryption license generation means 7 Multiplexing means 9, 15 Communication processing means 11, 11A, 11B Content reception apparatus 13, 13a Separation means 17, 17a, 17b Security module 19, 19a Encryption Content decrypting means 21 Re-encryption decrypting means 23 Decoding means 25 Storage means 27 External input / output means

Claims (16)

In a content transmission apparatus that transmits content by a limited playback method,
A first content key for encrypting the content, a second content key used to re-encrypt the decrypted content obtained by decrypting the encrypted content on the receiving side, and Information specifying the re-encryption key for re-encrypting the decrypted content or the domain bind control information that is information about the generation method to be generated is encrypted with the license encryption key corresponding to the decryption key held on the receiving side. A content transmission apparatus comprising encrypted license generation means for generating an encrypted license. In a content transmission apparatus that transmits content by a limited playback method,
A first content key for encrypting a scramble key for scrambling the content, and a first content key used for re-encrypting the decrypted content obtained by decrypting the content encrypted by the scramble key on the receiving side. The decryption held on the receiving side is the two content keys and the information specifying the re-encryption key for re-encrypting the decrypted content on the receiving side or the domain binding control information that is information on the generating method to be generated A content transmission apparatus comprising: encrypted license generation means for generating an encrypted license encrypted with a license encryption key corresponding to a key.   The encrypted license generation means is information indicating whether or not to output the re-encrypted content re-encrypted on the receiving side together with the first content key, the second content key, and the domain binding control information. The content transmission apparatus according to claim 1, wherein the content transmission apparatus encrypts the content with the license encryption key.   The encrypted license generation means, together with the first content key, the second content key, and the domain binding control information, outputs the number-of-outputs control information that is information related to the control of the number of times of output of the re-encrypted content. 4. The content transmitting apparatus according to claim 1, wherein the content transmitting apparatus encrypts with a key.   The content transmission apparatus according to any one of claims 1 to 4, wherein the first content key and the second content key are equal.   The domain bind information is specified in advance by specifying a re-encryption key for re-encrypting the decrypted content in the second content key, or in a group for sending the re-encrypted content on the receiving side. 6. The generation method according to claim 1, wherein a generation method is generated by using a domain key that is a common key to be held and the second content key. Content transmission device. In order to send content using the limited playback method,
A first content key for encrypting the content, a second content key used to re-encrypt the decrypted content obtained by decrypting the encrypted content on the receiving side, and Information specifying the re-encryption key for re-encrypting the decrypted content or the domain bind control information that is information about the generation method to be generated is encrypted with the license encryption key corresponding to the decryption key held on the receiving side. Encryption license generation means for generating an encrypted encryption license,
Encryption means for encrypting the content using the first content key;
A multiplexing means for multiplexing the encrypted content encrypted by the encryption means and the encrypted license generated by the encrypted license generating means;
A content transmission program that is made to function as: In order to send content using the limited playback method,
A first content key for encrypting a scramble key for scrambling the content, and a first content key used for re-encrypting the decrypted content obtained by decrypting the content encrypted by the scramble key on the receiving side. The decryption held on the receiving side is the two content keys and the information specifying the re-encryption key for re-encrypting the decrypted content on the receiving side or the domain binding control information that is information on the generating method to be generated Encrypted license generation means for generating an encrypted license encrypted with a license encryption key corresponding to the key;
Encryption means for encrypting the content using the scramble key;
A multiplexing means for multiplexing the encrypted content encrypted by the encryption means and the encrypted license generated by the encrypted license generating means;
A content transmission program that is made to function as: In a content receiving apparatus that receives and outputs an encrypted content obtained by encrypting content and an encrypted license including a first content key used when obtaining the encrypted content.
Decrypt the encryption license, re-encrypt the first content key, a second content key used to re-encrypt the decrypted content obtained by decrypting the encrypted content, and the decrypted content Encryption license decryption means for obtaining information specifying a re-encryption key to be generated or domain binding control information which is information relating to a generation method to be generated;
Using the first content key obtained by the encrypted license decryption means, decrypt the encrypted content and obtain the decrypted content;
Based on the domain bind control information, only the second content key, or the second content key and a common key held in advance in a group for sending the re-encrypted content obtained by re-encrypting the decrypted content Re-encryption key generation means for generating a re-encryption key used when re-encrypting the decrypted content using a domain key;
Re-encrypting the decrypted content using the re-encryption key generated by the re-encryption key generating means, and re-encrypting / decrypting means for decrypting the re-encrypted content;
A content receiving apparatus comprising: In a content receiving apparatus that receives and outputs an encrypted content in which the content is encrypted and an encrypted license including a scramble key used to obtain the encrypted content,
After decrypting the encryption license, it is used to re-encrypt the first content key for decrypting the ECM-Kc including the scramble key and the decrypted content obtained by decrypting the encrypted content. Encrypted license decryption means for obtaining a second content key to be obtained, and domain bind control information that is information specifying a re-encryption key for re-encrypting the decrypted content or information relating to a generation method to be generated,
ECM-Kc decryption means for decrypting the ECM-Kc using the first content key obtained by the encryption license decryption means, and obtaining the scramble key;
Using the scramble key obtained by the ECM-Kc decrypting means, decrypting the encrypted content and obtaining the decrypted content;
Based on the domain bind control information, only the second content key, or the second content key and a common key held in advance in a group for sending the re-encrypted content obtained by re-encrypting the decrypted content Re-encryption key generation means for generating a re-encryption key used when re-encrypting the decrypted content using a domain key;
Re-encrypting the decrypted content using the re-encryption key generated by the re-encryption key generating means, and re-encrypting / decrypting means for decrypting the re-encrypted content;
A content receiving apparatus comprising: In a content receiving apparatus that receives and outputs an encrypted content obtained by encrypting content and an encrypted license including a first content key used when obtaining the encrypted content.
After decrypting the encryption license, the first content key, a second content key used to re-encrypt the decrypted content obtained by decrypting the encrypted content, and the decrypted content are Domain binding control information that is information specifying a re-encryption key for encryption or information relating to a generation method that is generated, and output that is information regarding whether or not re-encrypted content obtained by re-encrypting the decrypted content is output Encrypted license decryption means for obtaining permission information;
Using the first content key obtained by the encrypted license decryption means, decrypt the encrypted content and obtain the decrypted content;
Based on the domain bind control information, using only the second content key or the second content key and a domain key that is a common key stored in advance in a group for sending the re-encrypted content, Re-encryption key generation means for generating a re-encryption key used when re-encrypting the decrypted content;
Re-encrypting the decrypted content using the re-encryption key generated by the re-encryption key generating means, and re-encrypting / decrypting means for decrypting the re-encrypted content,
The content receiving apparatus characterized in that the re-encryption / decryption means outputs the re-encrypted content to the outside based on the output permission / inhibition information. In a content receiving apparatus that receives and outputs an encrypted content obtained by encrypting content and an encrypted license including a first content key used when obtaining the encrypted content.
After decrypting the encryption license, the first content key, a second content key used to re-encrypt the decrypted content obtained by decrypting the encrypted content, and the decrypted content are Domain binding control information that is information specifying a re-encryption key for encryption or information relating to a generation method that is generated, and output that is information regarding whether or not re-encrypted content obtained by re-encrypting the decrypted content is output Encrypted license decryption means for obtaining permission information and output count control information that is information relating to control of the output count of the re-encrypted content;
Using the first content key obtained by the encrypted license decryption means, decrypt the encrypted content and obtain the decrypted content;
Based on the domain bind control information, using only the second content key or the second content key and a domain key that is a common key stored in advance in a group for sending the re-encrypted content, Re-encryption key generation means for generating a re-encryption key used when re-encrypting the decrypted content;
Re-encrypting the decrypted content using the re-encryption key generated by the re-encryption key generating means, and re-encrypting / decrypting means for decrypting the re-encrypted content,
The content receiving apparatus characterized in that the re-encryption / decryption means outputs the re-encrypted content to the outside based on the output permission information and the output count control information. In a content receiving apparatus that receives and outputs an encrypted content in which the content is encrypted and an encrypted license including a scramble key used to obtain the encrypted content,
After decrypting the encryption license, it is used to re-encrypt the first content key for decrypting the ECM-Kc including the scramble key and the decrypted content obtained by decrypting the encrypted content. The second content key, information specifying a re-encryption key for re-encrypting the decrypted content, or domain binding control information that is information relating to a generation method to be generated, and the decrypted content are re-encrypted. Encrypted license decryption means for obtaining output propriety information which is information relating to whether or not to output the re-encrypted content;
ECM-Kc decryption means for decrypting the ECM-Kc using the first content key obtained by the encryption license decryption means, and obtaining the scramble key;
Using the scramble key obtained by the ECM-Kc decrypting means, decrypting the encrypted content and obtaining the decrypted content;
Based on the domain bind control information, only the second content key, or the second content key and a common key held in advance in a group for sending the re-encrypted content obtained by re-encrypting the decrypted content Re-encryption key generation means for generating a re-encryption key used when re-encrypting the decrypted content using a domain key;
Re-encrypting the decrypted content using the re-encryption key generated by the re-encryption key generating means, and re-encrypting / decrypting means for decrypting the re-encrypted content,
The content receiving apparatus characterized in that the re-encryption / decryption means outputs the re-encrypted content to the outside based on the output permission / inhibition information. In a content receiving apparatus that receives and outputs an encrypted content in which the content is encrypted and an encrypted license including a scramble key used to obtain the encrypted content,
After decrypting the encryption license, it is used to re-encrypt the first content key for decrypting the ECM-Kc including the scramble key and the decrypted content obtained by decrypting the encrypted content. The second content key, information specifying a re-encryption key for re-encrypting the decrypted content, or domain binding control information that is information relating to a generation method to be generated, and the decrypted content are re-encrypted. Encrypted license decryption means for obtaining output permission information that is information regarding whether or not to output re-encrypted content and output number control information that is information regarding control of the number of times of output of the re-encrypted content;
ECM-Kc decryption means for decrypting the ECM-Kc using the first content key obtained by the encryption license decryption means, and obtaining the scramble key;
Using the scramble key obtained by the ECM-Kc decrypting means, decrypting the encrypted content and obtaining the decrypted content;
Based on the domain bind control information, only the second content key, or the second content key and a common key held in advance in a group for sending the re-encrypted content obtained by re-encrypting the decrypted content Re-encryption key generation means for generating a re-encryption key used when re-encrypting the decrypted content using a domain key;
Re-encrypting the decrypted content using the re-encryption key generated by the re-encryption key generating means, and re-encrypting / decrypting means for decrypting the re-encrypted content,
The content receiving apparatus characterized in that the re-encryption / decryption means outputs the re-encrypted content to the outside based on the output permission information and the output count control information. In order to receive and output an encrypted content in which the content is encrypted and an encrypted license including the first content key used in obtaining the encrypted content,
After decrypting the encryption license, the first content key, a second content key used to re-encrypt the decrypted content obtained by decrypting the encrypted content, and the decrypted content are Encryption license decryption means for obtaining information specifying a re-encryption key for encryption or domain bind control information which is information relating to a generation method for generation;
Encrypted content decrypting means for decrypting the encrypted content and obtaining the decrypted content using the first content key obtained by the encrypted license decrypting means,
Based on the domain bind control information, only the second content key, or the second content key and a common key held in advance in a group for sending the re-encrypted content obtained by re-encrypting the decrypted content Re-encryption key generating means for generating a re-encryption key used when re-encrypting the decrypted content using a domain key;
Re-encryption means for re-encrypting the decrypted content using the re-encryption key generated by the re-encryption key generating means, and for decrypting the re-encrypted content;
A content receiving program that is made to function as: In order to receive and output an encrypted content in which the content is encrypted and an encryption license including a scramble key used to obtain the encrypted content,
After decrypting the encryption license, it is used to re-encrypt the first content key for decrypting the ECM-Kc including the scramble key and the decrypted content obtained by decrypting the encrypted content. Encrypted license decryption means for obtaining a second content key to be obtained, and information specifying a re-encryption key for re-encrypting the decrypted content, or domain binding control information which is information relating to a generation method for generating,
ECM-Kc decryption in which the scramble key is encrypted with the first content key and decrypted using the first content key obtained by the encryption license decryption means to obtain the scramble key means,
Using the scramble key obtained by the ECM-Kc decrypting means, decrypting the encrypted content and obtaining the decrypted content;
Based on the domain bind control information, only the second content key, or the second content key and a common key held in advance in a group for sending the re-encrypted content obtained by re-encrypting the decrypted content Re-encryption key generating means for generating a re-encryption key used when re-encrypting the decrypted content using a domain key;
Re-encryption means for re-encrypting the decrypted content using the re-encryption key generated by the re-encryption key generating means, and for decrypting the re-encrypted content;
A content receiving program that is made to function as:

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