JP2005322360A - Recording method, reproducing method, recording device, reproducing device, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly reproduce encrypted contents. <P>SOLUTION: When recording content data in a predetermined storage after encrypting by a cryptography, some of the content data are encrypted by a encryption system which is different from the one used to encrypt the whole content data or are not encrypted, and placed in the fringe data, and recorded together with the content data in the storage (recording medium). When reproducing the content data recorded in the storage, they are reproduced, after encrypting the content data in the fringe data by a decryption system different from the one used to decrypt the whole content data encrypted by another system or without decrypting them. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recording method and a reproducing method for recording encrypted content data in a storage and reproducing the recorded data, a recording apparatus and a reproducing apparatus for recording and reproducing the data, and recording and reproduction with these apparatuses The present invention relates to a recording medium that performs

  Conventionally, for copyright protection and the like, content data such as audio data is encrypted and recorded in various storages. As storage, which is a recording medium, various recording (storage) media such as a memory card, a magneto-optical disk, and a hard disk with a built-in semiconductor memory are used. Note that when a memory or the like is used, it is often referred to as storage. However, when recording is described in this specification, the storage is also included.

  In addition, when content data such as audio data is recorded in various storages, data attached to content called fringe data is generally recorded simultaneously in the storage. Recording the fringe data is not directly related to the encryption of the content data. Normally, even when the content data is encrypted, it is recorded in the storage without being encrypted.

  The fringe data includes various information attached to the content, song title, title, playback time, artist name, and the like. In the fringe data, a tag is defined for each item (title, artist name, etc.), and information about the tag is embedded after the tag with a character string or binary data.

  FIG. 11 is a sequence diagram showing a procedure for reproducing encrypted content data recorded in a conventional storage. In this example, content data encrypted by the descrambling (decryption) module is decrypted based on a command from the software instructing playback, and the decrypted content data is played back by the playback module. It is a thing.

  First, the fringe information attached to the content data is acquired on the software side instructing the reproduction (step S1). Based on the acquired fringe information, information related to the content (such as a list of song titles) is displayed on the GUI screen of the playback device (step S2). When the user selects content from the GUI screen, the decryption module is instructed to decrypt the selected content (step S3).

  The descrambling module determines whether or not the instructed content can be decrypted (step S4). If decryption is possible, the content is decrypted (step S5). Then, the decrypted content data is sent to the playback module to start playback (step S6). Content decryption and playback are performed in parallel. Thereafter, when the playback of one unit of content in the playback module is completed, a playback end instruction is issued from the playback module to the descrambling module or the playback instruction software side (step S7).

As one of the processes for appropriately protecting the copyright of the content data by such encryption, a part of the encryption key used for encrypting the content is a device code (device ID) given to the playback device. (See Patent Document 1). By using the device code as part of the encryption key in this way, reproduction of the encrypted content data recorded in the storage is limited to a specific device with the same device code, and the copy is used. Is effectively limited.
JP 2002-319661 A

  However, as shown in FIG. 11, when the encrypted content data is reproduced, the decryption by the descrambling module is always required, and the decryption process is performed after the reproduction instruction is given by the software that issues the reproduction instruction. There is a problem that it takes a long time until the playback is actually started. Specifically, for example, in the case of audio data, it generally takes 1 to several seconds until the sound of the actually designated song is output after the playback operation is performed, and the waiting time is troublesome. .

  In particular, when audio data of a plurality of songs is recorded in one storage and the beginning of the plurality of songs is played back one after another to perform an operation for finding a song the user is looking for, for example, per song If it takes an extra time even for one second, for example, it will take an extra thirty seconds just by replaying the head of 30 songs one after another, which will be very time consuming. In recent years, the storage capacity of storage has increased, and the amount of data recorded in one storage tends to increase. The number of cases where this is a problem is increasing.

  The present invention has been made in view of such a point, and an object thereof is to enable quick reproduction of encrypted content.

  The present invention provides an encryption method different from an encryption method in which a part of content data is applied to the entire content data when content data is encrypted with a predetermined encryption method and recorded in a predetermined storage. Encrypted with or without encryption, it is arranged in the fringe data, and the fringe data in which a part of the content data is arranged is recorded in the storage (recording medium) together with the content data, and is recorded in the storage When playing back the content data, the content data in the fringe data is decrypted with a method different from the decryption with the encryption method applied to the entire content data or without decryption. It is intended to play.

  In this way, for example, a part of the content data placed in the fringe data is encrypted so that it can be decrypted with a light operation (or not encrypted), and placed in the fringe data during playback. By reproducing a part of the content data, it is possible to reproduce a part of the content data with a lighter operation (or in a state where no decoding operation is necessary) than the decoding operation required for reproducing the content data body. become.

  According to the present invention, a part of the content data can be played back with a lighter computation (or in a state where no decryption computation is necessary) than the decryption computation required for reproducing the content data main body. This part of the data can be played back. Therefore, for example, when the content is stream data such as audio or video, a predetermined portion such as the head portion of the stream can be quickly reproduced, and the operability of the stream data reproducing apparatus is improved.

  In this case, a storage (recording medium) in which a part of the content data is arranged in the fringe data may be created at the time of recording the content data, and the playback device determines the content of the fringe data at the time of playback, and the content data If there is a part of the data, it is only necessary to perform processing for reproducing the data, and the reproducing apparatus only has to manage the area to be reproduced from the storage and the like.

  In addition, part of the content data arranged in the fringe data is data of a predetermined section from the beginning of the stream data, and when reproducing over the predetermined section and a section other than the predetermined section, the decoding method is switched. By playing continuously, only the top part can be played back with less computation processing, and a search for playing back multiple contents one after another can be performed quickly, and it is simply played back continuously from the top of the contents. Even in such a case, there is an effect that it is possible to shorten the waiting time that was necessary until the decryption from the conventional encryption is completed.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
In this example, as shown in FIG. 1, a portable audio device 20 is connected to a personal computer device 10, and content data (audio data, etc.) downloaded by the computer device 10 via the Internet or the like is stored in the audio device. The content data recorded in the storage device 20 is played back by the audio device 20.

  Here, audio data is handled as content data. When the audio data is recorded by the audio device 20, the audio data is encrypted by processing in the computer apparatus 10, and the encrypted data is converted into audio data. The data is recorded in a storage attached to the device 20 and is played back by the audio device 20.

  First, the configuration of the computer device 10 will be described. The computer device 10 performs a data calculation process based on the control unit 11, the ROM 12 storing a program to be processed by the control unit 11, and the control of the control unit 11. A RAM 13 used as an execution area and a data storage unit 14 for storing downloaded data, processed data, and the like are prepared and are connected by a bus line so that data can be transferred between them. For example, a hard disk drive device is used as the data storage unit 14.

  Further, the communication unit 15 is provided as means for communicating with a predetermined communication network in a wired or wireless manner and connected to the Internet or the like, and for example, various content data can be downloaded from a server. Furthermore, a user interface unit 16 to which an input unit such as a keyboard and a pointing device is connected, and a display unit 17 including a display unit such as a liquid crystal display panel and a display driver for driving display on the display unit are provided. In addition to being able to be operated by the user, various displays can be made on the display unit 17. The input means and the display means are integrated when the computer device is a so-called notebook computer device, but may be separate. Further, a peripheral device interface unit 18 is prepared, and peripheral devices can be connected by a serial bus line of a predetermined standard. As the peripheral device interface unit 18, for example, a USB (universal serial bus) standard is used, and the peripheral device is connected via a USB terminal. Or it is good also as a structure which communicates with a peripheral device by the standard which performs near field communication.

  The computer apparatus 10 is installed with software for encrypting audio data downloaded via the Internet or the like, and transferring the encrypted audio data to the audio device 20 and recording it in the storage. In this software, fringe data attached to the encrypted audio data is also generated and recorded in the storage together with the encrypted audio data. As already described in the background section, the fringe data includes various information attached to the content, song title, title, playback time, artist name, etc. Further, in this example, a part of the audio data is included. Is included. A specific configuration of the fringe data of this example will be described later.

  The audio device 20 is a portable audio recording / reproducing apparatus that uses a detachable magneto-optical disk called a mini disk (MD) as a recording medium (storage). The audio signal (analog audio signal or disc audio data) input from the input terminal 21 can be recorded in the storage 40 and the audio signal (analogue) reproduced from the storage 40 is provided. Audio signal or disc audio data) is output from the output terminal 22.

  The audio input / output processing unit 23 is connected to the input terminal 21 and the output terminal 22 and performs input processing and output processing. The audio data to be recorded and processed by the audio input / output processing unit 23 is supplied to the recording / playback data processing unit 24 to have a data structure for recording in the storage 40, and the generated recording data is converted into the recording / playback unit 25. And processing for recording in the storage 40 is performed. At the time of recording, not only the audio data itself that is data of the content body but also fringe data attached to the content is recorded in the storage 40. The fringe data is sometimes called a TOC (table of contents) depending on the system, and is recorded in a separate area on the storage from the content body. Here, the recording / reproducing unit 25 includes a spindle motor that rotates the storage 40 that is a disk-shaped recording medium, a pickup that accesses the disk, and the like.

  Further, the data reproduced from the storage 40 by the recording / reproducing unit 25 is supplied to the recording / reproducing data processing unit 24 to perform reproduction data processing, and the obtained audio data is supplied to the audio input / output processing unit 23 for output. Processing to output from the terminal 22 is performed. For example, headphones (not shown) are connected to the output terminal 22.

  These recording and reproduction processes are performed based on the control of the control unit 26 which is a control means for controlling the processing in each unit in the device 20. When decryption from encryption is necessary at the time of reproduction, the reproduction data supplied to the recording / reproduction data processing unit 24 is decrypted under the control of the control unit 26. If a device code (device ID) is required at the time of decoding, the control unit 26 sends a code assigned to the device.

  A RAM 27 is connected to the control unit 26. For example, fringe data in data reproduced from the storage 40 is transferred to the RAM 27 and used for reproduction control or the like. The control unit 26 is supplied with an operation command from an operation unit 28 including operation keys and controls display on the display unit 29. The operation unit 28 and the display unit 29 may be separate from the device 20.

  In addition, an interface unit 30 for connecting to the computer apparatus 10 is provided, and data can be transferred by performing wired or wireless communication with the peripheral device interface unit 18 on the computer apparatus 10 side. The data transfer between the computer apparatus 10 and the audio device 20 is executed by the control units 11 and 26 of both devices 10 and 20 communicating with each other and controlled by the respective control units 11 and 26. When content data or fringe data is transferred from the computer apparatus 10 to the interface unit 30 on the audio device 20 side, it is sent to the recording / playback data processing unit 24 and recorded in the storage 40.

  Next, processing when audio data is encrypted and recorded in the storage 40 in the system configuration shown in FIG. 1 will be described with reference to the sequence diagram of FIG. In this example, the encryption process is performed on the computer device 10 side, and the audio device 20 records the content data main body and the fringe data in the storage 40 as they are. Here, as the encryption method, two types of encryption methods are prepared: a first encryption algorithm and a second encryption algorithm.

  Among these, the first encryption algorithm is an encryption method specific to the processing of this example, which is performed on a part of data arranged in the fringe data, and the second encryption algorithm is: This is an encryption method applied to the content data body from before. In the first encryption algorithm, the amount of computation required for decrypting the encrypted data is smaller than the amount of computation required for decryption by the second encryption algorithm, and can be easily decrypted with relatively light computation. It is like that. The second encryption algorithm is, for example, an encryption algorithm in which a decodable device is limited to a specific device. Specific examples of the first and second encryption algorithms will be described later.

  The sequence diagram of FIG. 2 is an instruction from the software for recording instructions implemented in the computer apparatus 10, and encrypts the audio data downloaded via the Internet or the like in the computer apparatus 10, and the audio data This shows a process for creating (correcting) fringe data. The encrypted audio data and the created fringe data are sent to the audio device 20 and recorded in the storage.

  Referring to the sequence diagram of FIG. 2, first, after specifying a portion to be encrypted by the first encryption algorithm (step S11), the processing program is instructed to encrypt the audio data (content data) (step S12). ). The portion that is encrypted by the first encryption algorithm is, for example, data of about several tens of seconds at the beginning of the audio data (or data of about several tens of seconds of the main part).

  For the audio data in the range instructed in step S11, a copy of the data is taken, and the copied data is encrypted with the first encryption algorithm (that is, the light encryption algorithm), and the memory in the computer apparatus is stored. (Step S13).

  Then, the entire audio data is encrypted with the second encryption algorithm (step S14). Thereafter, the encrypted data stored in the buffer in step S13 is arranged at a position specified in the format to generate fringe data (step S15). The encrypted audio data created in step S14 and the fringe data created in step S15 are transferred to the audio device 20 and recorded in the storage.

  Here, an example of an area where fringe data is written on the storage is shown in FIG. For example, as shown in FIG. 3A, a content attached data area and an audio data attached information area are prepared adjacent to an encrypted audio data area. The content-attached data area is recorded with the content-attached data area header followed by the content-attached tag 1, data corresponding to the tag 1, content-attached tag 2, data corresponding to the tag 2,. Data is recorded. The tag here is a data unit defined for each item of fringe data. Using one of the tags, data obtained by encrypting a part of data of one content by a light encryption method is used. Be placed. The audio data ancillary information area is adjunct information specific to audio, such as the length of a song.

  Alternatively, as shown in FIG. 3B, a content ancillary data area is prepared in an area different from the encrypted audio data area where the content is recorded, and the content ancillary data area is collectively Record the content-attached data file. The content-attached data area is recorded with the content-attached data area header, the content-attached tag 1, data corresponding to the tag 1, data attached to the content-attached tag 2, data corresponding to the tag 2,. Data is recorded collectively.

  Alternatively, a part of the fringe data is recorded adjacent to the encrypted audio data area as shown in FIG. 3 (a), and the remaining fringe data is encrypted as shown in FIG. 3 (b). The data may be recorded collectively in a different area from the normalized audio data area. How fringe data is recorded in the storage depends on the recording format of the storage (recording medium).

  Next, an example of encryption performed on content data will be described. FIG. 4 is a diagram showing an encryption example 1. In this example, the content key that is the encryption key (key) generated by the content key generation unit 1 is sent to the calculation unit 3 in the computer device 10, and the content data stored in the content data storage unit 2 is transmitted. The operation unit 3 encrypts the data. Further, the content key is also sent to the arithmetic unit 4, encrypted with the common key, and the encrypted content data and the encrypted content key are sent to the audio device 20 as one system data by the adder 5. Here, the encrypted content key is transferred, for example, attached to the header of the encrypted content. In addition to this, the header of the encrypted content is attached with license information with the usage conditions of the content appended, and the audio device 20 reproduces the content according to the license information.

  As shown in FIG. 4, the audio device 20 holds the hash value in the form of MAC and ICV so that the license is not rewritten. When calculating the ICV value, a device ID, which is a device-specific code, is used. The audio device 20 promises to verify the validity of the MAC and ICV values every time the content is played, so that the content can be played only by that device (that is, the state bound to the device). Realized.

  FIG. 5 is a diagram showing an encryption example 2. In this example, the device ID of the device 20 connected at that time held in the device ID holding unit 6 in the computer device 10 is sent to the calculation unit 7 and acquired in advance and stored in the content data storage unit 2. The content data thus encrypted is encrypted by the calculation unit 7. The encrypted content data is sent to the audio device 20.

  The audio device 20 decrypts the content using the device ID for each reproduction. By doing so, the encrypted content cannot be played back by another device.

  The encryption algorithm having a relatively large amount of computation required for encryption and decryption and high secrecy as shown in FIG. 4 and FIG. 5 is the second encryption algorithm described above. The entire content data is encrypted with the second encryption algorithm.

  The first encryption algorithm applied to a part of the content data arranged in the fringe data is applied with encryption that has a smaller calculation amount and can be decrypted relatively easily. . For example, an encryption algorithm that can be decrypted by multiplication (calculation) with a predetermined constant value at the time of decryption is used. Alternatively, the encryption algorithm can be decrypted by multiplication (calculation) with the title data of the song. Alternatively, an encryption algorithm that can decrypt unencrypted data (hereinafter referred to as raw data) as a data array opposite to a normal data array by data rearrangement is used.

  Next, processing when reproducing the content data (audio data) encrypted in this way and sent to the audio device 20 and recorded in the storage 40 will be described with reference to FIG. At the time of this reproduction, the audio device 20 is not normally connected to the computer apparatus 10 and the reproduction process is performed by the audio device 20 alone.

  The control unit 26 in the audio device 20 causes the display unit 29 of the device to display a reproduction list of songs recorded in the storage 40 attached. FIG. 7 is a diagram showing an example of a reproduction list. The title of the song is determined based on the fringe data. As shown in FIG. 7, the user selects the music displayed in the reproduction list by operating the rotary operation means 28a.

  Returning to the description of FIG. 6, when there is a song whose selection is confirmed by such display or the like, data for instructing the reproduction of the selected content data is passed to the processing program executing the reproduction process (step S21). . When this instruction is given, the processing program first extracts the data of the portion written in the first encryption algorithm, which is arranged in the fringe data, for the corresponding content (step S22). At that time, the extracted data is decrypted, and a command is sent to the playback module to perform playback immediately (step S23).

  Thereafter, it is determined whether or not the content body designated in step S21 can be reproduced (step S24). Further, the reproduction module performs reproduction based on the data given from the processing program in step S23.

  The reproduction module notifies the processing module of a pre-termination message before the reproduction of data given from the processing program is completed (step S25). The processing module starts decrypting the content body based on the notification in step S25 (step S27). At this time, the decryption is started from the portion following the portion of data written by the first encryption algorithm. If it is determined in step S24 that the content body is not a reproducible content, this process is not performed. A reproduction module is given a fade-out command to terminate reproduction (step S26).

  If the content body is successfully decrypted, data is sequentially supplied to the playback module, and playback is continued without interruption. When playback of one content is completed, a playback end notification is given (step S28).

  In addition, when another content in the playlist is designated from the application that issues the playback instruction until the playback ends after the start of playback, all processing is immediately ended, The process from step S22 is started for the newly designated song.

  FIG. 8 shows a summary of the processing of this example described so far. That is, as shown in FIG. 8 (a), when the encrypted content data d10, d20, d30... And the encrypted content 1, 2, 3,. Part of the content data d11, d21, and d31 is copied and placed in the fringe as data d12, d22, and d32 that have been encrypted with a small amount of calculation and written to the storage. . Part d11, d21, and d31 of the content data is data of several tens of seconds at the maximum of the top part or main part of each content.

  For example, if there is a reproduction instruction for the content 1, as shown in FIG. 8 (b), it is determined whether or not there is some data d12 of the content data in the fringe data of the content 1. If there is data d12, the data d12 is decoded from the head and reproduced. When the reproduction of the portion of the data d12 is completed and further reproduction is performed (when reproduction is possible), the encrypted content data d10 of the portion following the data d12 is decrypted and reproduced, and the content 1 is completed. Continue to play until

  By processing in this way, when each content is reproduced, it is first reproduced from a part of the content data arranged in the fringe data. In this case, since a part of the content data arranged in the fringe data is lightly encrypted data with a small amount of decryption calculation, it can be quickly decrypted without taking time and a reproduction instruction is given. Playback with audio data output can be started with almost no waiting time, and the operability as a playback device is improved. In particular, when performing a search operation in which the beginning and main parts of a large number of songs (contents) are reproduced one after another for a short time, each song is immediately reproduced without waiting time, so that the operability is greatly improved.

  In the description so far, a part of the content data arranged in the fringe data is lightly encrypted. However, it is encrypted as a part of the content data arranged in the fringe data. As raw data, it may be possible to reduce the processing load at the time of searching.

  The sequence diagram of FIG. 9 is an example of a write process to the storage in that case. The processing will be described with reference to FIG. 9. First, after specifying a portion to be encrypted by the first encryption algorithm (step S51), the processing program is instructed to encrypt the audio data (content data) (step S51). S52). The portion that is encrypted by the first encryption algorithm is, for example, data of about several tens of seconds at the beginning of the audio data (or data of about several tens of seconds of the main part).

  For the audio data in the range designated in step S51, a copy of the data is taken, and the copied data is stored as it is (that is, as raw data) in a buffer constituted by a memory in the computer device ( Step S53).

  Then, the entire audio data is encrypted with the second encryption algorithm (step S54). Thereafter, the raw data stored in the buffer in step S53 is arranged at a position designated in the format to generate fringe data (step S55). The encrypted audio data created in step S54 and the fringe data created in step S15 are transferred to the audio device 20 and recorded in the storage.

  FIG. 10 shows an example of processing for reproducing data recorded in the storage in this way. Referring to FIG. 10, when there is a song for which playback selection has been confirmed, data for instructing playback of the selected content data is passed to the processing program executing playback processing (step S61). When this instruction is given, the processing program first takes out the data of the content written as the raw data of the content arranged in the fringe data for the corresponding content (step S62), and immediately reproduces it to the reproduction module. A command is sent to perform (step S63).

  Thereafter, it is determined whether or not the content body designated in step S61 can be reproduced (step S64). The reproduction module performs reproduction based on the data given from the processing program in step S63.

  The reproduction module notifies the processing module of a pre-end message before the reproduction of data given from the processing program is completed (step S65). The processing module starts decrypting the content body based on the notification in step S65 (step S67). At this time, decoding is started from the portion following the raw data. If it is determined in step S64 that the content body is not a reproducible content, this process is not performed. A reproduction module is given a fade-out command to terminate reproduction (step S66).

  If the content body is successfully decrypted, data is sequentially given to the playback module, and playback is continued without interruption. When playback of one content is completed, a playback end notification is sent (step S68).

  In addition, when another content in the playlist is designated from the application that issues the playback instruction until the playback ends after the start of playback, all processing is immediately ended, The process from step S62 is started for the newly instructed music.

  In this way, a part of the content data to be written in the fringe data is recorded as raw data, so at the start of reproduction of each content data, it is not necessary to decrypt the content data from encryption, which is very easy Can be played.

  In the embodiment described so far, a personal computer device and an audio device are connected, content data downloaded on the personal computer device side is encrypted in the personal computer device, and fringe data is also stored in the computer device. However, the present invention can also be applied to the case where content data is encrypted and recorded with other configurations. For example, the input content data may be encrypted by an audio device that is a recording / playback device, and the fringe data may be generated in the audio device and recorded in the storage. Or conversely, a storage for recording content may be attached to the personal computer device, and all recording processing may be performed by the computer device. The process of generating fringe data at the time of recording as in the present invention and the process of using a part of the content data in the fringe data at the time of reproduction are implemented in various computer devices if they are softwareized (programmed). Can be configured to be processed.

  As for storage, a recording medium other than the disk-shaped recording medium such as the above-described magneto-optical disk, for example, a hard disk or a memory card incorporating a semiconductor memory is used as a recording medium (storage). Also good. In this case, there are a case where a recording medium that is detachable from the apparatus main body such as a magneto-optical disk or a memory card is used, and a case that a recording medium that is not removable from the apparatus main body such as a hard disk is used. Any storage may be used as long as the storage is configured to be attached to the content data.

  The content data itself can also be applied to the case where content data other than audio data is recorded and reproduced. For example, the present invention can be applied to recording and reproducing video data. In the case of stream data such as audio data and video data, for example, the head portion (or main portion) is recorded in the fringe data by the processing of the present invention, so that playback from the head (or main portion) can be performed. It has an effect that can be done quickly.

It is a block diagram which shows the example of whole structure by one embodiment of this invention. It is the sequence diagram which showed the process which writes a part of content data by encrypting to the fringe by one embodiment of this invention. It is explanatory drawing which showed the example of the fringe information by one embodiment of this invention. It is explanatory drawing which showed the encryption example 1 by one embodiment of this invention. It is explanatory drawing which showed the encryption example 2 by one embodiment of this invention. It is the sequence diagram which showed the example of reproduction | regeneration by one embodiment of this invention. It is explanatory drawing which showed the example of a display by one embodiment of this invention. It is explanatory drawing which showed the process outline | summary by one embodiment of this invention. It is the sequence diagram which showed the process which writes a part of content data, without encrypting to the fringe by other embodiment of this invention. It is the sequence diagram which showed the example of reproduction | regeneration by one embodiment of this invention. It is the sequence diagram which showed the example of conventional reproduction | regeneration.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Computer apparatus, 11 ... Control part, 12 ... ROM, 13 ... RAM, 14 ... Data storage part, 15 ... Communication part, 16 ... User interface part, 17 ... Display part, 18 ... Peripheral device interface part, 20 ... Audio Equipment: 21 ... Input terminal, 22 ... Output terminal, 23 ... Audio input / output processing section, 24 ... Recording / playback data processing section, 25 ... Recording / playback section, 26 ... Control section, 27 ... RAM, 28 ... Operation section, 29 ... Display unit, 30 ... interface unit, 40 ... storage

Claims (17)

In a recording method in which content data is encrypted by a predetermined encryption method and recorded in a predetermined storage,
A part of the content data is encrypted with an encryption method different from the predetermined encryption method, or placed in fringe data without being encrypted,
A recording method in which fringe data in which a part of the content data is arranged is recorded in the storage together with the content data. The recording method according to claim 1,
The encryption method that is different from the predetermined encryption method is an encryption method that requires less calculation processing amount than the predetermined encryption method. The recording method according to claim 1,
The predetermined encryption method is an encryption method in which a code assigned to a device to be reproduced is used as part or all of an encryption key. The recording method according to claim 1,
The content data is stream data including audio or video, and a part of the content data is data in a predetermined section from the head of the stream data. In a reproduction method for reproducing content data recorded in a predetermined storage and encrypted by a predetermined encryption method,
When a part of the content data is arranged in the fringe data recorded in the storage together with the content data,
A reproduction method for reproducing content data in the fringe data with or without decryption by a method different from the decryption by the encryption method. The reproduction method according to claim 5, wherein
The decoding method according to the present invention is a method in which the decryption of a method different from the decryption by the predetermined encryption method is a method that requires less calculation processing amount than the predetermined encryption method. The reproduction method according to claim 5, wherein
The predetermined encryption method is an encryption method in which a code assigned to a device to be reproduced is used as part or all of an encryption key. The reproduction method according to claim 5, wherein
The content data is stream data including audio or video, and a part of the content data is data in a predetermined section from the head of the stream data,
A playback method of switching between decoding methods and continuously playing back when playing back over the predetermined section and sections other than the predetermined section. An encryption means for encrypting the content data with a predetermined encryption method;
Fringe data creation means for creating fringe data for the content data encrypted by the encryption means;
Output means for outputting the content data encrypted by the encryption means and the fringe data created by the fringe data creation means for recording in a predetermined storage;
As the fringe data creation means,
A recording apparatus that performs a process of encrypting a part of the content data by an encryption method different from the predetermined encryption method, or arranging the content data in the fringe data without encryption. The recording apparatus according to claim 9, wherein
The encryption method applied to the content data arranged in the fringe data is different from the predetermined encryption method. The encryption method requires less calculation processing amount than the predetermined encryption method. Is a recording device. The recording apparatus according to claim 9, wherein
The predetermined encryption method is an encryption method that uses a code assigned to a playback device as part or all of an encryption key. The recording apparatus according to claim 9, wherein
The content data is stream data including audio or video, and a part of the content data is data in a predetermined section from the head of the stream data. In a playback device for playing back content data encrypted by a predetermined encryption method recorded in a predetermined storage,
Decryption means for decrypting the encrypted content data read from the storage;
Output means for outputting the content data decrypted by the decrypting means;
The content of the fringe data recorded in the storage together with the content data is judged, and when a part of the content data is arranged, the content data in the fringe data is decrypted by the encryption method. And a control means for outputting from the output means without decoding or without decoding. The playback device according to claim 13, wherein
The decoding apparatus according to the present invention is a method in which the decryption of a method different from the decryption by the predetermined encryption method is a method that requires less calculation processing amount than the predetermined encryption method. The playback device according to claim 13, wherein
The predetermined encryption method is an encryption method in which a code assigned to the reproduction device is used as part or all of an encryption key. The playback device according to claim 13, wherein
The content data is stream data including audio or video, and a part of the content data is data in a predetermined section from the head of the stream data,
The control device is a playback device that, when playing back over the predetermined section and a section other than the predetermined section, switches the decoding method to continuously play back and output from the output means. Content data encrypted with a predetermined encryption method,
In a recording medium on which fringe data about the content data is recorded,
A recording medium in which, as the fringe data, a part of the content data is encrypted with an encryption method different from the predetermined encryption method, or is not encrypted.

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