JP2006099701A - Recorder and data input/output method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recorder realizing proper management of a copy without excessively restricting flexibility of content use of a user. <P>SOLUTION: In this recorder encrypting and decrypting a content on the basis of content control information included in a license, the content including the same content identifier as a content identifier is encrypted to the license including a content decryption key and the content identifier for uniquely identifying the content control information and the content, and the license is updated with a key for decrypting the encrypted content as a content decryption key of the license. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a data input / output method and a recorder for recording or reproducing content requiring copyright protection.

  In December 2003, digital terrestrial broadcasting was started in some areas. Since the content broadcast by terrestrial digital broadcasting is digital content and has the characteristic that information does not deteriorate even if copying is repeated, means for imposing restrictions on the copying of this content from the viewpoint of copyright protection. is needed.

  There is a CGSM (Copy Generation Management System) as a system for appropriately managing such copies, and in terrestrial digital broadcasting, “00” is not restricted by digital copy control information (2 bits) in the digital copy control description. Copy restriction, "01" is defined by the operator, "10" is copyable for only one generation, and "11" is copy prohibition.

  In terrestrial digital broadcasting, since many contents are scheduled to be broadcast with digital copy control information set to “10”, that is, only one generation can be copied, the contents are recorded on a recording medium for private use. But I can't copy from the recorded content.

  For this reason, it is not possible to make a backup in advance in case the content is damaged. If the content is damaged, the user cannot use the content unless rebroadcasting is performed.

  On the other hand, in the current analog broadcasting, it is possible to take a backup in preparation for content damage, and if an acquaintance etc. recorded on a video etc., a copy can be taken from the video, Even if the content is damaged, the user can often use the content.

  As described above, when the current terrestrial analog broadcast is shifted to the digital broadcast, the user's degree of freedom in using the content may be limited.

In Patent Document 1, by acquiring a license from the outside, content data in a digital format that cannot be originally copied can be stored in a data storage device. If the data storage fails, up to a specific amount is made via a network. Thus, there is shown a technique for obtaining correct data and making it possible to change error data in a data storage device.
JP 2003-333507 A

  According to the technology described in Patent Document 1, when data being copied is broken for some reason, data can be acquired and recovered again via a network using a license acquired from the outside. .

  However, this method cannot be used when a license relating to content control is not provided from the outside, that is, when a recorder or the like performs copy control using a copy control license internally, When the encrypted content is damaged, the problem that the content cannot be used even though the license is possessed cannot be solved.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a recorder that realizes proper management of copying without excessively limiting the degree of freedom of content usage by users. That is.

  In view of the above problems, the present invention has the following features.

  The invention of claim 1 is a recorder for recording / reproducing content, wherein a key generation unit for generating a key used for content encryption / decryption, and a content generated by using the key generated by the key generation unit are provided. A content encryption unit for encrypting, a license generation unit for generating a license including content identification information for uniquely identifying content and the key, and a storage area, and recording input data in the storage area And a storage device unit that reads and outputs data recorded in the storage area, an encrypted content output unit that outputs the encrypted content to the storage device unit, and the license to the storage device unit. And a license output unit for outputting.

  The invention of claim 2 is the recorder according to claim 1, wherein the encrypted content acquisition unit for acquiring the encrypted content recorded in the storage device unit, and the license recorded in the storage device unit are acquired. Corresponding to each of these encrypted contents with respect to two encrypted contents, a license obtaining part that performs the decryption part that decrypts the obtained encrypted content using a key used for decrypting the encrypted content A determination unit that determines whether the license to be included includes the same content identification information, wherein each of the two encrypted contents is determined for the first encrypted content and the second encrypted content in the determination unit. It is determined that the first license and the second license corresponding to the same content identification information are included. The decryption unit decrypts the first encrypted content with the key included in the first license, and uses the decrypted content as the third content. The key generation unit encrypts the third content. A key used for decryption is generated, the license generation unit generates a third license including the content identification information and the generated key, and the content encryption unit uses the generated key to generate the third license. The third content is encrypted, the encrypted content output unit outputs the third encrypted content as the second encrypted content to the storage device unit, and the license output unit outputs the third content. A license is output to the storage device unit as the second license.

  A third aspect of the present invention is the recorder according to the first or second aspect, wherein the storage device unit includes a storage area for normal data and a confidential data storage area for confidential data. .

  The invention according to claim 4 is the recorder according to any one of claims 1 to 3, wherein when the license is recorded in the confidential data storage area, the license output unit is connected to the storage device unit. An encryption communication path is constructed between the licenses, and the license is output via the encryption communication path.

  The invention according to claim 5 is the recorder according to any one of claims 1 to 3, wherein when the license is read from the confidential data storage area, the license acquisition unit is connected to the storage device unit. In this case, an encryption communication path is constructed, and the license is acquired through the encryption communication path.

  According to a sixth aspect of the present invention, there is provided data in a recorder for recording / reproducing contents, comprising a storage area, recording input data in the storage area, and reading out and outputting the data recorded in the storage area An input / output method for generating a key used for content encryption / decryption, encrypting the content using the generated key, and content identification information for uniquely identifying the content and a license including the key And generating the encrypted content and the license.

  The invention according to claim 7 is the data input / output method according to claim 6, wherein the encrypted content and the license recorded in the storage device unit are acquired, and the acquired encrypted content is converted into the encrypted content. And decrypting with the key used for decryption of the two encrypted contents, it is determined whether the license corresponding to each of the encrypted contents includes the same content identification information. When it is determined that the first license and the second license corresponding to each of these two encrypted contents include the same content identification information The first encrypted content is decrypted with the key included in the first license, and this is used as the third content. Generating a key used for encryption / decryption of the file, generating a third license including the content identification information and the generated key, and encrypting the third content using the generated key, The third encrypted content is output as the second encrypted content, and the third license is output as the second license.

  The invention according to claim 8 is the data input / output method according to claims 6 and 7, wherein the recording area includes a storage area for normal data and a confidential data storage area for confidential data, When recording the license in the data storage area, the license is output by encrypted communication.

  A ninth aspect of the present invention is the data input / output method according to the sixth or seventh aspect, wherein the recording area includes a storage area for normal data and a confidential data storage area for confidential data, When the license is read from the data storage area, the license is acquired by encrypted communication.

  The “content encryption unit” of the recorder in the claims mainly corresponds to the common key encryption / decryption unit 201 of the encryption / decryption processing unit 107 in the embodiment. The “license generating unit” of the recorder in the claims corresponds mainly to the license processing unit 204 of the encryption / decryption processing unit 107 in the embodiment. The “encrypted content output unit” and “license output unit” of the recorder in the claims mainly correspond to the control unit 205 and storage device interface unit 108 of the encryption / decryption processing unit 107 in the embodiment.

  The features of the present invention and the technical significance thereof will become more apparent from the following description of embodiments. However, the following embodiment is only one embodiment of the present invention, and the meaning of the present invention or the terms of each constituent element is limited to those described in the following embodiment. is not.

  According to the present invention, a re-license can be generated using a license having the same content identifier, and proper management of copying can be realized without excessively limiting the user's freedom of content usage. be able to.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a configuration of a recorder 10 according to the present embodiment. As shown, the recorder 10 includes a main control unit 101, a tuner unit 102, a demodulation unit 103, a TS DEMUX unit 104, an AV decoding unit 105, a program information processing unit 106, an encryption / decryption processing unit 107, and a secure storage medium interface unit 108. And is configured to receive broadcast waves via an external antenna 109.

  The main control unit 101 comprehensively controls the components of the recorder 10.

  The tuner unit 102 receives a specific broadcast wave signal from the broadcast waves received by the antenna unit 109, performs analog / digital conversion, and transmits the analog / digital conversion to the demodulation unit 103.

  The demodulation unit 103 performs demodulation, error correction processing, and the like by a predetermined method for the broadcast wave converted into a digital format by the tuner unit 102. The demodulated data is transmitted to the TS DEMUX unit 104 when played back in real time, and is transmitted to the encryption / decryption processing unit 107 when recorded in the storage device 20. The

  The TS DEMUX unit 104 separates the multiplexed TS packet transmitted from the demodulation unit 103 into an encoded video / audio data packet and a program information data packet. Among these, the encoded video / audio data packet is transmitted to the AV decoding unit 105, and the program information data packet is transmitted to the program information processing unit 106.

  The AV decoding unit 105 decodes the transmitted encoded video / audio data packet. Decode encoded video / audio data.

  The program information processing unit 106 analyzes the transmitted program information data packet.

  The encryption / decryption processing unit 107 encrypts plaintext data transmitted from the demodulation unit 103, that is, the multiplexed TS packet in this embodiment. In addition, decryption processing is performed on the encrypted data output from the storage device 20 and, in the present embodiment, the encrypted TS packet. Details will be described later.

  The storage device interface unit 108 is an interface that controls input / output with the storage device 20.

  The antenna 109 receives a broadcast wave and transmits it to the tuner unit 102.

The storage device 20 has a configuration for encrypting and exchanging confidential data when the confidential data is input and output with the recorder 10. In addition, in order to store confidential data, a confidential data storage area different from a normal storage area is provided, and input / output of data to the confidential data storage area is an encryption / decryption processing unit provided in the storage device 20 Is performed only by a recorder verified to have a legitimate authority. The configuration of the encryption / decryption processing unit provided in the storage device 20 is the same as the configuration of the encryption / decryption processing unit 107 of the recorder 10.
As an example of this storage device, there is a secure recording medium disclosed in Japanese Patent Laid-Open No. 2003-256286.

  FIG. 2 shows a configuration of the encryption / decryption processing unit 107 according to the embodiment. As illustrated, the encryption / decryption processing unit 107 includes a public key encryption / decryption unit 201, a common key encryption / decryption unit 202, a certificate verification unit 203, a license processing unit 204, a control unit 205, a key generation unit 206, and the like. A data bus 207 is provided for electrical connection.

  The public key encryption / decryption unit 201 performs encryption and decryption by a public key cryptosystem using an asymmetric key.

  The common key encryption / decryption unit 202 performs encryption and decryption by a common key encryption method using a symmetric key.

  The certificate verification unit 203 verifies the validity of the storage device 20 using the certificate output from the storage device 20.

  The license processing unit 204 creates a new license. Also, the transmitted license is analyzed.

  The control unit 205 controls the components of the encryption / decryption processing unit 107 in an integrated manner, and controls data input / output between the components. Further, it controls input / output of data to / from the TS DEMUX unit 107 and the storage device interface unit 108 outside the encryption / decryption processing unit 107.

  The key generation unit 206 generates a challenge key and a session key used by the public key encryption / decryption unit 201.

  In the following description, the certificate data C (X, Y) indicates that the data Y has a signature that can be verified with the verification key X. Information E (X, Y) indicates that the data Y is encrypted so that it can be decrypted with the decryption key X.

  FIG. 3 shows details of the license data. The license data includes License ID, Content ID, Crypto Key, Copy Control, and License Status.

  The License ID includes information such as a model ID for identifying a model, a machine ID for identifying a machine belonging to the same model, and a local ID uniquely used for each machine, and uniquely identifies a license created by each machine.

  The Content ID includes a program ID composed of concatenations such as Service ID, Event ID, and Start Time, and information such as a recording start time and a recording end time generated based on JST time. The digital ID content to be recorded can be uniquely identified by the program ID, and the actual recording range of the content can be specified by the recording start time and the recording end time.

  The Crypto Key is a content key used when performing encryption / decryption processing on digital content to be recorded.

  Copy Control includes a Digital Copy Control Descriptor and other necessary information, and indicates copy restrictions for the content to be recorded.

  License Status indicates the status of the license. In the present embodiment, the “provisional license” state indicating that the license is not yet completed when the corresponding content is encrypted, and the license when the corresponding content is encrypted. There is a “official license” status to indicate that there is. The “provisional license” state shifts to the “official license” state when the content encryption processing is completed.

  Next, the operation of the recorder 10 will be described.

  First, an operation in which the recorder 10 records content in the storage device 20 will be described.

  FIG. 4 is a flowchart schematically showing the content recording operation.

  When the main control unit 101 of the recorder 10 receives an instruction to record content in the storage device 20 from an input unit (not shown) (s100), the recorder 10 operates as shown in the figure.

  The content is transmitted as a digital broadcast wave signal from a broadcasting station or the like, and is received by the antenna unit 109 of the recorder 10. The received broadcast wave signal is transmitted to the tuner unit 102 (s102).

  The main control unit 101 instructs the tuner unit 102 to select a broadcast wave signal based on an instruction from a user or the like from an input unit (not shown).

  The tuner unit 102 selects a predetermined broadcast wave signal from the transmitted broadcast wave signal and transmits it to the demodulation unit 103.

  The demodulator 103 performs demodulation, error correction processing, and the like on the transmitted digital broadcast wave signal, extracts a TS packet, and transmits the TS packet to the TS_DEMUX unit 105 (s104).

  The TS_DEMUX unit 105 extracts an encoded video / audio data packet and a program information data packet from the transmitted TS packet. The extracted encoded video / audio data packet is transmitted to the encryption / decryption processing unit 107. The program information data packet is transmitted to the program information processing unit 106 (s106).

  In the program information processing unit 106, a service identification (Service ID) for identifying a service, an event identification (Event ID) for identifying an event, and an event start time (Start) from an EIT (Event Information Table) included in the program information data packet Time), a digital copy control descriptor (Digital Copy Control Descriptor) is extracted. This digital copy control descriptor is information used to control the copy generation in the digital recording device. Also, the current date, current time (JST time), etc. are extracted from TDT (Time and Date Table).

  The extracted information is transmitted to the encryption / decryption processing unit 107 and used when generating a license (s108).

  The key generation unit 206 generates a content key for encrypting the content. Further, the information transmitted to the encryption / decryption processing unit 107 is transmitted to the license processing unit 204 in the encryption / decryption processing unit 107, and the license processing unit 204 performs processing for the content to be recorded based on the transmitted information. Generate license data License. At this point, since the content encryption process has not been completed, the License Status included in the generated license data is information indicating that the license is a temporary license. The generated license data is held in the license processing unit 204 until this processing is completed (s110).

  The license data generated in s110 is recorded in the storage device 20 via the storage device interface 108 (s112).

  5 and 6 show a detailed procedure in the license recording of s112.

  In the encryption / decryption processing unit 107, when the control unit 205 requests a certificate from the storage device 20 via the storage device interface 108 (s200), the storage device 20 stores the certificate data C (KPa, KPd1). Is output to the recorder 10 (s202).

  The certificate data C (KPa, KPd1) output from the storage device 20 is transmitted to the encryption / decryption processing unit 107 via the storage device interface 108 of the recorder 10 (s204), and the proof in the encryption / decryption processing unit 107 is obtained. The document verification unit 203 performs verification using the verification key KPa (s206).

  If the certificate is not valid as a result of the verification (s206N), a verification error is notified and the process is terminated.

  On the other hand, if the certificate is valid as a result of the verification (s206Y), the certificate verification unit 203 extracts the decryption key KPd1 from the certificate data C (KPa, KPd1), and then the key generation unit 206 performs the challenge key. Kch1 is generated (s208).

  Next, the public key encryption / decryption unit 201 encrypts the generated challenge key Kch1 so that it can be decrypted with the extracted decryption key KPd1 to generate first challenge information E (KPd1, Kch1). The generated first challenge information E (KPd1, Kch1) is output to the storage device 20 via the storage device interface 108 (s210).

  Upon receiving the first challenge information E (KPd1, Kch1) output from the recorder 10 (s212), the storage device 20 decrypts this and extracts the challenge key Kch1 (s214), and holds the extracted challenge key Kch1 (S216).

  Subsequently, a session key Ks1 is generated (s218), and the generated session key Ks1 is encrypted so that it can be decrypted with the challenge key Kch1 held in s216, thereby generating first session information E (Kch1, Ks1). (S220). The generated first session information E (Kch1, Ks1) is output to the recorder 10 (s222).

  The recorder 10 receives the first session information E (Kch1, Ks1) transmitted from the storage device via the storage device interface 108 (s224).

  The received first session information E (Kch1, Ks1) is decrypted using the challenge key Kch1 in the common key encryption / decryption unit 202, and the session key Ks1 is extracted (s226).

  Subsequently, the common key encryption / decryption unit 202 performs encryption such that the license data License generated in s110 can be decrypted with the session key Ks1, and generates encrypted license data E (Ks1, License). The generated encrypted license data E (Ks1, License) is output to the storage device 20 via the storage device interface 108 (s228).

  When the storage device 20 receives the encrypted license data E (Ks1, License) output from the recorder 10 (s230), the storage device 20 decrypts the extracted license data License (s232), and the extracted license data License is predetermined. Is recorded in the confidential data storage area (S234).

  An encryption communication path for transmitting license data is established between the recorder 10 and the storage device 20 according to the procedure of s200 to s234, and the license data is generated from the recorder 10 to the storage device 20 via the encryption communication path in s108. License data is recorded.

  Returning to FIG. 4, the encoded video / audio data packet transmitted to the encryption / decryption processing unit 107 uses the content key generated in s110 in the common key encryption / decryption unit 202 in the encryption / decryption processing unit 107. Encrypted. The encrypted content data is recorded in a normal storage area of the storage device 20 via the storage device interface 108 (s114).

  When the content encryption processing and recording processing are completed, the main control unit 101 instructs the encryption / decryption processing unit 107 to update the License Status included in the license data to information indicating that the license is an official license. .

  Based on this instruction, the encryption / decryption processing unit 107 updates the license License Status of the license data generated in s110 to information indicating that the license is an official license, and repeats the procedure from s200 to s234 to repeat the procedure of the recorder 10 and the storage. An encryption communication path is established with the device 20 and the license data is updated (s116). After updating the license data, the main control unit 101 ends this process.

  Next, an operation in which the recorder 10 reproduces content recorded in the storage device 20 will be described.

  7 and 8 are flowcharts schematically showing the content reproduction operation.

  When the main control unit 101 of the recorder 10 receives an instruction to reproduce the content recorded in the storage device 20 from an input unit (not shown), the recorder 10 operates as shown in FIGS.

  First, when the control unit 205 in the encryption / decryption processing unit 107 outputs the certificate data C (KPa, KPd2) including the public key KPd2 to the storage device 20 via the storage device interface 108 (s300), The storage device 20 receives the certificate data C (KPa, KPd2) output from the recorder 10 (s304), and verifies it using the verification key KPa (s304).

  As a result of this verification, if the certificate is not valid (s304N), the recorder 10 is notified of a verification error, and the main control unit 101 of the recorder 10 ends this processing.

  On the other hand, if the certificate is valid as a result of the verification (s304Y), the decryption key KPd2 is extracted from the certificate data C (KPa, KPd2) and held (s306). Subsequently, a challenge key Kch2 is generated (s308), encryption is performed so that the generated challenge key Kch2 can be decrypted with the extracted decryption key KPd2, and second challenge information E (KPd2, Kch2) is generated (s310). . The generated second challenge information E (KPd2, Kch2) is output to the recorder 10 (s312).

  When the recorder 10 receives the second challenge information E (KPd2, Kch2) output from the storage device 20 via the storage device interface 108 (s314), the public key encryption / decryption unit 201 receives the public key KPd2 Is used to extract the challenge key Kch2 (s316), and the extracted challenge key Kch2 is held (s318).

  Subsequently, the key generation unit 206 generates a session key Ks2 (s320), and the common key encryption / decryption unit 202 performs encryption such that the generated session key Ks2 can be decrypted with the challenge key Kch2 held in s318. To generate second session information E (Kch2, Ks2). The generated second session information E (Kch2, Ks2) is transmitted to the recorder 10 via the storage device interface 108 (s322).

  The storage device 20 receives the second session information E (Kch2, Ks2) output from the recorder 10 (s324).

  The received second session information E (Kch2, Ks2) is decrypted using the challenge key Kch2 to extract the session key Ks2 (s326), and the extracted session key Ks2 is held (s328).

  Subsequently, the license data License recorded in the confidential data storage area is read out, encrypted so that it can be decrypted with the session key Ks2, and encrypted license data E (Ks2, License) is generated (s332). The generated encrypted license data E (Ks2, License) is output to the recorder 10 (s324).

  Upon receiving the encrypted license data E (Ks2, License) output from the storage device 20 via the storage device interface 108, the recorder 10 transmits this to the common key encryption / decryption unit 202 (s336). The common key encryption / decryption unit 202 decrypts the transmitted encrypted license data E (Ks2, License) and extracts the license data License (s338). Subsequently, a content key is extracted from the extracted license data License (s340).

  According to the procedure of s300 to s340, an encryption communication path for transmitting license data is established between the recorder 10 and the storage device 20, and license data is read from the storage device 20 to the recorder 10 via the encryption communication path.

  On the other hand, the control unit of the recorder 10 reads the encrypted content data recorded in the normal storage area of the storage device 20 through the storage device interface 108, and reads the read encrypted content data into the encryption / decryption processing unit 107. (S342).

  The encrypted content data transmitted to the encryption / decryption processing unit 107 is transmitted to the common key encryption / decryption unit 202, and decrypted using the content key extracted in s340 (s344).

  The decrypted content is transmitted to the TS_DEMUX unit 104. The TS_DEMUX unit 104 extracts an encoded video / audio data packet from the transmitted content, and the extracted encoded video / audio data packet is transmitted to the AV decoding unit 105, where video and audio are decoded. (S346).

  The content recorded in the storage device 20 can be reproduced by the above procedure. However, at the time of reproduction, for example, there is a possibility that the reproduced video or audio is abnormal, that is, the content itself is damaged.

  In such a case, the content is recovered by the recovery process described below, and can be reproduced again.

  In the present embodiment, the damaged content (hereinafter referred to as the first encrypted content) is converted into another normal encrypted content (hereinafter referred to as the first encrypted content) having the same program ID as the first encrypted content. 2) (referred to as “encrypted content”). The recovery operation will be described below.

  FIG. 9 shows the procedure of this recovery operation.

  When the main control unit 101 of the recorder 10 receives a content recovery instruction from an input unit (not shown), the recorder 10 operates as shown in FIG.

  The recorder 10 establishes an encrypted communication path with the storage device 20 according to the above-described procedures from s300 to s338, and the encrypted content (hereinafter referred to as “No. A license including a content key (hereinafter referred to as a first content key) for decrypting the encrypted content (hereinafter referred to as a first content key) is acquired, and the license processing unit 204 acquires the acquired first license. (S400).

  Next, similarly, a license (hereinafter referred to as a second license) including a content key (hereinafter referred to as a second content key) of normal encrypted content that is not damaged (hereinafter referred to as a second encrypted content) is obtained. (S402).

  The control unit 205 in the encryption / decryption processing unit 107 compares the first license and the second license, and determines whether the program IDs are the same (s404). When the program IDs are not the same (s404N), this process ends.

  When the program IDs are the same in s404 (s404Y), the control unit 205 compares the first license with the second license and determines whether to perform recovery (s406). Specifically, if the license IDs are the same (s406Y), one of them may be a copy of the other content, so this process ends.

  When it is determined in s404 that recovery is possible (s406N), the key generation unit 206 generates a new content key (hereinafter, third content key), and the license processing unit 204 uses the first license transmitted in s400. On the other hand, the third license key generated instead of the first content key is replaced as the content key, and the first license is updated (s408).

  The updated first license rewrites the first license recorded in the confidential data area of the storage device 20 via the encrypted communication path with the storage device 20 established by the procedure from s200 to s234 described above. (S410).

On the other hand, the control unit of the recorder 10 reads the encrypted content data recorded in the normal storage area of the storage device 20 via the storage device interface 108, and sends the read encrypted content data to the encryption / decryption processing unit 107. introduce. The encryption / decryption processing unit 107 decrypts the transmitted encrypted content data using the second content key extracted from the second license, and then encrypts the encrypted content data using the third content key to perform the third encryption. Content is generated (s412).
The generated third encrypted content is replaced with the first encrypted content recorded in the normal storage area of the storage device 20 via the storage device interface 108 (s414).

  In this way, the damaged content can be recovered and played back again.

  Note that, with respect to the recorder 10 of the present embodiment, the operation of reproducing the content received by the recorder 10 from a broadcast wave or the like as it is is the same as the conventional one, and the description thereof is omitted.

  According to the above embodiment, the encrypted content can be decrypted only with the content key included in the corresponding license, and there is only one license, so that the copy of the content can be managed appropriately. .

  In addition, even when a content is damaged while having a valid license, the content can be recovered by re-encrypting the content using another valid identical content and regenerating the license.

  Also, when recording content, the License Status shows the temporary license status indicating that processing has not been completed and the official license status indicating that processing has been completed, so content that normally takes a long time It can be detected that the encrypted content remains complete for some reason during the process, and the necessity of the recovery process can be determined.

  As mentioned above, although embodiment which concerns on this invention was described, it cannot be overemphasized that this invention is not limited to this embodiment, and various changes are possible.

In the above embodiment, the storage device 20 is a storage medium that can be attached to and detached from the recorder 10, such as a removable hard disk drive, but may be a storage medium that is built in the recorder 10.
The embodiment of the present invention can be appropriately modified in various ways within the scope of the technical puncture indicated in the claims.

It is a block diagram which shows the structure of the recorder which concerns on embodiment. It is a block diagram which shows the structure of the encryption / decryption process part which concerns on embodiment. It is a figure which shows the license structure which concerns on embodiment. It is a flowchart which shows roughly the license recording operation | movement which concerns on embodiment. It is a flowchart which shows roughly the license recording operation | movement which concerns on embodiment. It is a flowchart which shows roughly the license recording operation | movement which concerns on embodiment. It is a flowchart which shows roughly the license reproduction | regeneration operation | movement which concerns on embodiment. It is a flowchart which shows roughly the license reproduction | regeneration operation | movement which concerns on embodiment. 4 is a flowchart schematically showing a recovery operation according to the embodiment.

Explanation of symbols

10 recorder 20 storage device

Claims (9)

In a recorder that records and plays back content,
A key generation unit for generating a key used for content encryption / decryption;
A content encryption unit that encrypts content using the key generated by the key generation unit;
A license generating unit for generating a license including content identification information for uniquely identifying content and the key;
A storage device unit that includes a storage area, records input data in the storage area, and reads and outputs the data recorded in the storage area;
An encrypted content output unit for outputting the encrypted content to the storage device unit;
A recorder comprising: a license output unit that outputs the license to the storage device unit. The recorder according to claim 1, wherein
An encrypted content acquisition unit for acquiring encrypted content recorded in the storage device unit;
A license acquisition unit for acquiring a license recorded in the storage device unit;
A decryption unit that decrypts the acquired encrypted content using a key used to decrypt the encrypted content;
A determination unit that determines, for two encrypted contents, whether a license corresponding to each of the encrypted contents includes the same content identification information;
Further comprising
In the determination unit, for the first encrypted content and the second encrypted content, the first license and the second license corresponding to each of these two encrypted contents include the same content identification information. When it is determined that
The decryption unit decrypts the first encrypted content with the key included in the first license, and uses this as the third content,
The key generation unit generates a key used for encryption / decryption of the third content,
The license generation unit generates a third license including the content identification information and the generated key;
The content encryption unit encrypts the third content using the generated key,
The encrypted content output unit outputs the third encrypted content as the second encrypted content to the storage device unit,
The license output unit outputs the third license as the second license to the storage device unit;
A recorder characterized by that. A recorder according to claim 1 and claim 2,
The storage device unit includes a storage area for normal data and a confidential data storage area for confidential data.
A recorder characterized by that. A recorder according to any one of claims 1 to 3,
When recording the license in the confidential data storage area, the license output unit establishes an encrypted communication path with the storage device unit, and outputs the license via the encrypted communication path.
A recorder characterized by that. A recorder according to any one of claims 1 to 3,
When reading the license from the confidential data storage area, the license acquisition unit establishes an encrypted communication path with the storage device unit, and acquires the license via the encrypted communication path.
A recorder characterized by that. A data input / output method in a recorder for recording / reproducing content, comprising a storage area, recording input data in the storage area, and reading and outputting the data recorded in the storage area,
Generate a key used for content encryption / decryption,
Encrypt the content using the generated key,
Generating a license including content identification information for uniquely identifying the content and the key;
A data input / output method comprising outputting the encrypted content and the license. The data input / output method according to claim 6,
Obtain the encrypted content and license recorded in the storage device unit,
Decrypting the acquired encrypted content using a key used to decrypt the encrypted content;
For two encrypted contents, determine whether the license corresponding to each of these encrypted contents contains the same content identification information,
In the determination, for the first encrypted content and the second encrypted content, the first license and the second license corresponding to each of these two encrypted contents include the same content identification information. When it is determined that
The first encrypted content is decrypted with the key included in the first license, and this is used as the third content,
Generating a key used for encryption / decryption of the third content;
Generating a third license including the content identification information and the generated key;
Encrypting the third content using the generated key;
Outputting the third encrypted content as the second encrypted content;
Outputting the third license as the second license;
A data input / output method characterized by that. The data input / output method according to claim 6 or 7,
The recording area includes a storage area for normal data and a confidential data storage area for confidential data,
When recording the license in the confidential data storage area, the license is output by encrypted communication;
A data input / output method characterized by that. The data input / output method according to claim 6 or 7,
The recording area includes a storage area for normal data and a confidential data storage area for confidential data,
Obtaining the license by encrypted communication when reading the license from the confidential data storage area;
A data input / output method characterized by that.

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