Content using system

A content using system including a content importing apparatus and at least one content using apparatus that share a network key, where a content is bound to a network by encrypting content key information, which includes a content key required to decrypt the content, using the network key,

• the content importing apparatus including:
• an obtaining unit operable to obtain a content and encrypted content key information, which includes the content key for the content, from the outside;
• an ID generating unit operable to generate a content ID for identifying the content obtained by the obtaining unit;
• and
• an encryption converting unit operable to convert encryption by decrypting the encrypted content key information obtained by the obtaining unit, adding the content ID to the decrypted content key information, and re-encrypting the content key information using the network key,
• and each content using apparatus including:
• a first decrypting unit operable to decrypt the re-encrypted content key information using the network key;
• a second decrypting unit operable to decrypt the content using the content key in the content key information decrypted by the first decrypting unit;
• a writing unit operable to write the content decrypted by the second decrypting unit onto a storage medium;
• a table storing unit operable to store a table in which the content ID included in the content key information decrypted by the first decrypting unit is associated with a number of times the content corresponding to the content ID has been written by the writing unit;
• and
• a suppressing unit operable to obtain the content ID of the content to be written by the writing unit, to refer, in the table, to the number of times the content corresponding to the content ID has been written, and to suppress writing of the content by the writing unit when the number of times has reached a predetermined maximum number of times.

A content using system including a content importing apparatus and at least one content using apparatus that share a network key, where a content is bound to a network by encrypting content key information, which includes a content key required to decrypt the content, using the network key,

• the content importing apparatus including:
• an obtaining unit operable to obtain a content and encrypted content key information, which includes a content key for the content, from the outside;
• an ID generating unit operable to generate a content ID for identifying the obtained content;
• an encryption converting unit operable to convert encryption by decrypting the encrypted content key information obtained by the obtaining unit, adding the content ID to the decrypted content key information, and re-encrypting the content key information using the network key;
• a table storing unit operable to store a table that records the content ID of a content that has been written onto a storage medium by a content using apparatus;
• a table managing unit operable to use, when a write permission judgement request has been received from a content using apparatus, the table to judge whether writing of a content is permitted and to update the table based on a judgement result;
• and
• a content ID receiving unit operable to receive the write permission judgement request from the content using apparatus and to transmit the judgement result obtained from the table managing unit, and
• the content using apparatuses each including:
• a first decrypting unit operable to decrypt the re-encrypted content key information using the network key;
• a content ID transmitting unit operable to transmit to the content importing apparatus a write permission judgement request including the content ID included in the decrypted content key information and to receive the judgement result;
• a second decrypting unit operable to decrypt the content using the content key included in the content key information decrypted by the first decrypting unit only when the received judgement result shows that the writing is permitted;
• and
• a writing unit operable to write the content decrypted by the second decrypting unit onto a storage medium.

A content using system including a content importing apparatus and at least one content using apparatus that share a network key, where a content is bound to the network by encrypting content key information, which includes a content key required to decrypt the content, using the network key,

• the content importing apparatus including:
• an obtaining unit operable to obtain a content and encrypted content key information, which includes a content key for the content, from the outside;
• an ID generating unit operable to generate a content ID for identifying the obtained content;
• an encryption converting unit operable to convert encryption by decrypting the encrypted content key information obtained by the obtaining unit, adding the content ID to the decrypted content key information, and re-encrypting the content key information using the network key;
• a first table storing unit operable to store a table that records the content ID of a content that has been written onto a storage medium by a content using apparatus;
• a table managing unit operable to use, when a write permission judgement request has been received from a content using apparatus, the table to judge whether writing of a content is permitted and to update the table based on a judgement result;
• and
• a table transmitting unit operable to receive synchronization information from a content using apparatus and to transmit the table to the content using apparatus,
• and each content using apparatus including:
• a first decrypting unit operable to decrypt the re-encrypted content key information using an encryption key that has been shared in advance on the network and to output the content key;
• a table receiving unit operable to transmit synchronization information for the table that includes at least a content ID to the content importing apparatus and to receive the table;
• a second table storing unit operable to store the table;
• a table managing unit operable to update the table in the second table storing unit using the table received from the content importing apparatus and to judge whether writing of a content is permitted using the table;
• a second decrypting unit operable to decrypt the encrypted content using the content key only when a judgement result of the table managing unit shows that writing is permitted;
• and
• a writing unit operable to write the content decrypted by the second decrypting unit onto a storage medium.

A content using system including a content importing apparatus and at least one content using apparatus that share a network key and also a content writing apparatus that is connected to at least one of the at least one content using apparatuses and writes a content onto a storage medium, where a content is bound to the network by encrypting content key information, which includes a content key required to decrypt the content, using the network key,

• the content importing apparatus including:
• an obtaining unit operable to obtain a content and encrypted content key information, which includes the content key for the content, from the outside;
• an ID generating unit operable to generate a content ID for identifying the obtained content;
• and
• an encryption converting unit operable to convert encryption by decrypting the encrypted content key information obtained by the obtaining unit, adding the content ID to the decrypted content key information, and re-encrypting the content key information using the network key,
• each content using apparatus including:
• a first decrypting unit operable to decrypt the re-encrypted content key information using the network key;
• and
• a second decrypting unit operable to decrypt the content using the content key included in the decrypted content key information, and
• the content writing apparatus including:
• a writing unit operable to write a content onto a storage medium;
• a table storing unit operable to store a table for recording a content ID of the content written on the storage medium by the writing unit;
• and
• a table managing unit operable to judge whether writing of a content is permitted using the table and to control the writing unit in accordance with a judgement result.

A content using system in which a content importing apparatus and at least one content using apparatus are connected to a network,

• the content importing apparatus including:
• an encryption converting unit operable to convert encryption by decrypting encrypted content key information, generating secret information for influencing a content key, and re-encrypting the content key information using an encryption key that is shared in advance on the network and the secret information;
• and
• an output request processing unit operable to receive a content output request from a content using apparatus and to transmit a request response including at least the secret information,
• and the content using apparatus including:
• an output requesting unit operable to transmit an output request, which includes at least an output destination of a content, to the content importing apparatus, to receive the request response, and to obtain the secret information;
• a first decrypting unit operable to decrypt the re-encrypted content key information using an encryption key shared in advance on the network and the secret information;
• a control unit operable to output content output control information for controlling a selecting unit;
• a second decrypting unit operable to decrypt the encrypted content using the content key;
• a selecting unit operable to select an output destination of the content based on the content output control information;
• and
• at least one output unit operable to output the content.

A content using apparatus that uses a content that has been bound to a network by encrypting content key information, which includes a content key required to decrypt the content, using a network key,

• the content using apparatus comprising:
• a first decrypting unit operable to decrypt the re-encrypted content key information using the network key;
• a second decrypting unit operable to decrypt the content using the content key in the content key information decrypted by the first decrypting unit;
• a writing unit operable to write the content decrypted by the second decrypting unit onto a storage medium;
• a table storing unit operable to store a table in which the content ID included in the content key information decrypted by the first decrypting unit is associated with a number of times the content corresponding to the content ID has been written by the writing unit;
• and
• a suppressing unit operable to obtain the content ID of the content to be written by the writing unit, to refer, in the table, to the number of times the content corresponding to the content ID has been written, and to suppress writing of the content by the writing unit when the number of times has reached a predetermined maximum number of times.

A content importing apparatus that binds a content to a network to which a plurality of apparatuses that share a network key are connected by encrypting content key information, which includes a content key required to decrypt the content, using the network key,

• the content importing apparatus including:
• an obtaining unit operable to obtain a content and encrypted content key information, which includes a content key for the content, from the outside;
• an ID generating unit operable to generate a content ID for identifying the content obtained by the obtaining unit;
• and
• an encryption converting unit operable to convert encryption by decrypting the encrypted content key information obtained by the obtaining unit, adding the content ID to the decrypted content key information, and re-encrypting the content key information using the network key,
• wherein the content ID is used to manage writing of the content, which has been bound to the network, onto a storage medium in an unbound state.

A content using method of using a content on a network to which a plurality of apparatuses are connected,

• the method comprising:
• a binding step which is performed in at least one of the plurality of apparatuses and in which a content is bound to the network by putting the content in a state where only apparatuses on the network can use the content;
• an ID issuing step which is performed in at least one of the plurality of apparatuses and in which a content ID that corresponds to the content that has been bound to the network in the binding step is issued;
• a judging step which is performed in at least one of the plurality of apparatuses and in which a content ID of a content, which has been bound to the network and is to be written in an unbound state, is obtained, a table in which content IDs of contents that have already been written is recorded is referred to in a memory, and a judgement of whether writing the content is permitted is made;
• a bind removing step which is performed in at least one of the plurality of apparatuses and in which the content that has been bound to the network by the binding unit is put in an unbound state when the judgement in the judging step is that writing is permitted;
• and
• a writing step which is performed in at least one of the plurality of apparatuses and in which the content put in the unbound state in the bind removing step is written onto a storage medium.

A content using method performed by an apparatus that uses a content that has been bound to a network by encrypting content key information, which includes a content key that is required to decrypt the content, using a network key,

• the content using method comprising:
• a first decrypting step of decrypting the encrypted content key information using the network key;
• a second decrypting step of decrypting the content using the content key in the content key information decrypted in the first decrypting step;
• a judging step of obtaining a content ID of a content, which has been bound to the network and is to be written in an unbound state, referring to a table, in which content IDs of contents that have already been written is recorded, in a memory, and judging whether writing the content is permitted;
• and
• a writing step of putting the bound content into an unbound state and writing the content in the unbound state onto a storage medium when the judging step has judged that writing is permitted.

A content using program for a content using system that includes a content importing apparatus and at least one content using apparatus that share a network key, where a content is bound to the network by encrypting content key information, which includes a content key required to decrypt the content, using a network key, the content using program including a first program that is executed by the content importing apparatus and a second program that is executed by a content using apparatus,

• the first program having a computer function as:
• an obtaining unit operable to obtain a content and encrypted content key information, which includes a content key for the content, from the outside;
• an ID generating unit operable to generate a content ID for identifying the content obtained by the obtaining unit;
• and
• an encryption converting unit operable to convert encryption by decrypting the encrypted content key information obtained by the obtaining unit, adding the content ID to the decrypted content key information, and re-encrypting the content key information using the network key,
• and the second program having a computer function as:
• a first decrypting unit operable to decrypt the re-encrypted content key information using the network key;
• a second decrypting unit operable to decrypt the content using the content key in the content key information decrypted by the first decrypting unit;
• a writing unit operable to write the content decrypted by the second decrypting unit on a storage medium;
• a table storing unit operable to store a table in which the content ID included in the content key information decrypted by the first decrypting unit is associated with a number of times the content corresponding to the content ID has been written by the writing unit;
• and
• a suppressing unit operable to obtain the content ID of the content to be written by the writing unit, to refer, in the table, to the number of times the content corresponding to the content ID has been written, and to suppress writing by the writing unit when the number of times has reached a predetermined maximum number of times.

A content using program executed by an apparatus that uses a content that has been bound to a network by encrypting content key information, which includes a content key that is required to decrypt the content, using a network key,

• the program having a computer function as:
• a first decrypting unit operable to decrypt the encrypted content key information using the network key;
• a second decrypting unit operable to decrypt the content using the content key in the content key information decrypted by the first decrypting unit;
• a writing unit operable to write the content decrypted by the second decrypting unit onto a storage medium;
• a table storing unit operable to store a table in which the content ID included in the content key information decrypted by the first decrypting unit is associated with a number of times the content corresponding to the content ID has been written by the writing unit;
• and
• a suppressing unit operable to obtain the content ID of the content to be written by the writing unit, to refer, in the table, to the number of times the content corresponding to the content ID has been written, and to suppress writing by the writing unit when the number of times has reached a predetermined maximum number of times.