JP2000286887A - Encoder for contents data, recording medium, distribution method and user terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a scramble code from being recognized in the absence of audio data in a distribution system of contents data including the audio data. SOLUTION: An encoder 43A detects a non-voice period of audio data for each partial pack length of one pack length of the audio data and the audio data are scrambled for a voiced period by using an EX-OR circuit 2 that exclusively ORs the audio data with a PN code generated on the basis of a memory device ID and an output signal of a through-path is selected for a non-voice period or a period close thereto. Furthermore, a reproduction side applies a prescribed OR between the scrambled audio data with a scramble code to descramble the audio data for a voiced period and an output signal of the through-path is selected for a non-voice period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a content data encoding device, a recording medium, a distribution method, and a user terminal in a content data distribution system including audio data.

[0002]

2. Description of the Related Art Conventionally, a system for distributing music data and the like using a communication line (Japanese Patent Laid-Open No.
146820) and a system for distributing using a communication satellite (Japanese Patent Laid-Open Nos. 7-143081, 10-16399).
1) has been proposed.

[0003] The applicant of the present application has
A more specific proposal was made in Japanese Patent Application No. 10-288487, filed on 009. The main inventions in this proposal are:
"A user mobile terminal that transmits a mobile terminal ID and electronic money to a store-installed terminal and receives paid content data; a mobile terminal that receives the mobile terminal ID and the electronic money from the mobile terminal; And a store installation terminal that also transmits the installation terminal ID to the charging center, the content ID, and the mobile terminal I.
D, a billing center for receiving the installation terminal ID and the electronic money from the shop installation terminal,
D, receiving the mobile terminal ID and the installation terminal ID,
A content center that distributes the pay content data to the mobile terminal via the store-installed terminal, and a distribution system.

[0004] By the way, an example of distribution in such an example system is a fee, and due to a copyright management problem, scrambled content data to be charged is given by a predetermined method. As an example of the scrambling method, there is a method used for a DVD (digital video disk, digital versatile disk). In this system, the video data is CSS
(Content scramble system). In the CSS system, the original data is scrambled by exclusive-ORing the original data with a PN code as a scrambling code at the time of scrambling. Is exclusive-ORed and descrambled. As another example of the scrambling method, there is a scramble method in which a value obtained by a chaos function is added to original data at the time of scrambling, and a descrambling is performed by subtracting a chaos function value from the scrambled data at the time of descrambling.

[0005]

However, in the case of distributing content data including audio data, in particular, the audio signal has a silent section, and the audio data bits in the silent section become all zeros. For example, if this audio data is scrambled by taking an exclusive OR with the PN code, and if the exclusive OR of the scrambled data and the PN code is taken, the PN code is left as it is. There is a problem that the PN code is output and therefore the PN code is known.

In view of the above problems, the present invention takes an exclusive OR of audio data and a scramble code when scrambling in a system for distributing at least content data including audio data. It is an object of the present invention to provide a content data encoding device, a recording medium, a distribution method, and a user terminal that can prevent a scramble code and a chaos function used at the time from being known. Also, the present invention removes the memory device of the user terminal,
It is an object of the present invention to be able to use even when the terminal is attached to another terminal.

[0007]

The present invention, in order to achieve the above object, comprises the following 1) to 4). That is,

[0008] 1) A content data distribution system having at least a content center for distributing content data including at least audio data, and a user terminal for requesting the distribution of the content data, and connecting these via communication means for data distribution Means for detecting identification information uniquely assigned to the memory device from a memory device built in the user terminal; and a silent section for each partial data length of audio data having a predetermined data length. Means for detecting
In a section other than the silent section, the audio data is scrambled according to the identification information uniquely given to the memory device, and in the silent section, the audio data is not scrambled. Means for formatting into a data structure having the audio data and a flag indicating the presence or absence of scrambling.

[0009] 2) Distribution of content data that has at least a content center that distributes content data including at least audio data, and a user terminal that requests distribution of the content data, and that is connected by communication means to distribute data. A recording medium used in the system, wherein a silent section is detected for each partial data length of audio data having a predetermined data length, and the silent section is provided in accordance with identification information uniquely assigned to a memory device built in the user terminal. In a section that is not a section, the audio data is scrambled by a predetermined method. In the silent section, the audio data is not scrambled, and at least,
A recording medium for content data in which a data structure having the scrambled or unscrambled audio data and a flag indicating whether or not scrambling is performed is recorded.

[0010] 3) A content data distribution method in a content data distribution system having at least a content center that distributes content data including at least audio data, and a user terminal that requests distribution of the content data, Comprises a common header in which at least the ID of the user terminal is set, and a content set, wherein the content set detects a silent section for each partial data length of audio data having a predetermined data length, The audio data is scrambled by a predetermined method in a section other than the silent section based on a scramble key generated according to identification information uniquely assigned to a memory device built in the memory device. In the silent section, audio data is scrambled. Not Le, at least, the method of distributing content data, wherein the data and a flag indicating the presence or absence of the scrambled or unscrambled the audio data and the scramble is distributed are arranged.

[0011] 4) Distribution of content data that has at least a content center that distributes content data including at least audio data, and a user terminal that requests distribution of the content data, and that is connected by communication means to distribute data. The system is used for detecting a silent section for each partial data length of audio data having a predetermined data length, and for a section other than the silent section according to identification information uniquely assigned to a memory device built in the user terminal, The audio data is scrambled by the method described above, and the audio data is not scrambled in the silent section. A user terminal that performs descramble and deformat on the audio data according to the identification information uniquely assigned to the memory device in a section other than the silent section, and in the silent section based on the flag in the silent section. A user terminal having means for not descrambling audio data.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B are general concept block diagrams of a system for distributing content data including at least audio data to which the present invention is applied. The system includes a user portable terminal (transmission side) 40,
Store installation terminal 41, charging center (management center) 4
2. It comprises a content center 43, a communication line 44, a communication satellite 45, and a user portable terminal (reception side) 46.

Each of the portable terminals 40 and 46 has a unique identification code (hereinafter referred to as a player ID or a user terminal ID).
And ). In addition, each user portable terminal 40, 4
6, the memory device and each content also have a unique identification code (hereinafter, referred to as a memory device ID and a content ID). The mobile terminal 40 requests the store setting terminal 41 to transmit the content data. At this time, the mobile terminal 40 stores the content ID and the player I
D and the memory device ID are transmitted.

Each store-installed terminal 41 also has a unique identification code (hereinafter, referred to as a company ID). The installation terminal 41, which has been requested to transmit the content data, notifies the charging center 42 and the content center 43 together with the respective transmission data that the transmission of the content data has been requested from the mobile terminal 40.

The billing center 42 is notified of the content ID, the player ID, and the company ID. The billing center 42 sends a request to send a content data fee corresponding to the content ID to the mobile terminal 40 via the communication line 44 and the installation terminal 41 with reference to a fee table created in advance.

The portable terminal 40 requested to send the content data fee sends the electronic money to the charging center 42 via the installation terminal 41 and the communication line 44 as the content fee. As electronic money, an IC that stores a monetary amount on an IC chip and makes payment through an IC card reader
Card type electronic money (for example, Mondex, VISA
A cash) or an electronic wallet (for example, an NTT flexible electronic ticket) can be used.

When the billing center 42 receives the predetermined electronic money, it notifies the content center 43 of the receipt. Upon receiving the electronic money receipt notification from the charging center 42, the content center 43 sends the content data to the portable terminal 40 via the communication satellite 45 and the installation terminal 41.

After the portable terminal 40 receives the content data via the installation terminal 41, the portable terminal 40 can be detached from the installation terminal 41 and freely carried, and the received content data (for example, music data ) Can be played and enjoyed.

As shown in FIG. 1B, after receiving the content data, the portable terminal (transmitting side) 40 can be detached from the installation terminal 41, can be carried freely, and stored in the portable terminal (transmitting side) 40. The content data can be copied (transferred) to the portable terminal (reception side) 46. The installation terminal 41 does not participate in such copying. In other words, where there is no installation terminal 41, the mobile terminal (transmission side) 40
Content data can be copied between the portable terminal (receiving side) 46 and the portable terminal (receiving side) 46. A fee is also charged for copying the content data between the portable terminals, and electronic money corresponding to the content data fee is sent from the portable terminal (receiving side) 46 to the portable terminal (transmitting side) 40. When the content data is copied between the portable terminals, the portable terminal ID of the portable terminal (receiving side) 46 and the content ID of the copied content data are stored in the portable terminal (transmitting side) 40 as a transfer history. You. This transfer history is stored in the store installation terminal 4 together with the electronic money when the portable terminal (transmission side) 40 is connected to the store installation terminal 41 at a later date.
1 and transferred to the charging center 42. As a result, information as to which portable terminal has acquired which content and electronic money are collected at the charging center 42.

The portable terminal (transmitting side) 40 and the portable terminal (receiving side) 46 are distinguished as a “transmitting side” and a “receiving side” for the sake of convenience, but both have both transmitting and receiving functions. The same thing. The term “sending side” means that the data is transferred between the portable terminals, and the term “transmitting side” is used. The term “receiving side” is used when the data is transferred between the portable terminals. ”.

FIG. 2 is a block diagram showing the configuration of the transmitting-side encoding device. The encoding device 43A is installed in the content center 43 (FIG. 1) and is used to encode transmission data into a predetermined format.

In FIG. 2, for example, stereo two-channel L and R audio signals are converted into M-bit digital data for each channel by an A / D converter 1, and then M-bit data of each channel is converted into M bits in parallel. Is applied to one input terminal of one of the EX-OR circuits 2.
The PN code generator 3 has a scramble key determined by the scramble key determination unit 9 in accordance with the memory device ID, and one word is given an initial value for each sector. And outputs the parallel data to the other input terminal of the EX-OR circuit 2 in parallel.
An exclusive OR is obtained with the code and scrambled. The scrambled audio data is applied to one input terminal of the switch 4, and the audio data converted by the A / D converter 1 is applied to the other input terminal of the switch 4. The switch 4 is switched by the scramble setting flag Fsc, and the data selected by the switch 4 is applied to the DVD audio formatting circuit 8. Also, player ID data,
Similarly, the scramble key data (encryption key data) encrypted by the encryption unit 10 using the memory device ID is D
It is applied to the VD audio formatting circuit 8.

Further, 2 converted by the A / D converter 1
The audio signals of channels L and R are applied to silence section detectors 6L and 6R, respectively, and a silence section or a section close to silence is detected based on the reference data shown in detail in FIG. For example, a starter (first half) of a later-described audio data pack and a half position (second half) of the pack are detected by a detector including a data counter or the like (not shown). Reference data is referred to each time (each first half and second half of the pack). As shown in FIG. 3, the reference data is a code for determining whether or not N M-bit data are “+0” or “−0” continuously.
N is, for example, half of the number of words of the scrambling serial code = 64. This detection signal is ORed by the OR gate 7 to detect a silent section or a section close to silent on either channel, and the scramble setting flag F
The signal is applied to the control terminal of the switch 4 as sc. And
The switch 4 selects the output signal of the EX-OR circuit 2 in a non-silent section or a section not close to silence.
In a silent section or a section close to silent section, an output signal of a through path is selected.

DVD audio formatting circuit 8
Contains a scrambled or unscrambled audio data in a compressed PCM audio pack (A pack) in the title set of the applied physical information section, and sets a scramble setting flag Fsc to the physical data managing the data of the applied physical information section. It is stored in the information department.
When the above data is recorded on a DVD audio disk or a memory IC, data contained in a physical information section is recorded in a lead-in area, and data contained in an applied physical information section is recorded in a data area. It has become so. The area configuration of the DVD audio disk is a well-known configuration, and includes a PCA (post-cutting area) area, a lead-in area, a data area, and a lead-out area from the inner circumference to the outer circumference. .

FIG. 4 is a diagram showing an A-pack of the compressed PCM. The A-pack is composed of 2048 bytes or less, and is composed of a 14-byte pack header and an A packet. The A packet is composed of a packet header of 17, 9, or 14 bytes, a private header, and 1 to 2011 bytes of audio data (scrambled or unscrambled compressed PCM data).

The private header includes: an 8-bit substream ID; a 4-bit reserved area in the ISRC; a 4-bit ISRC number in the ISRC; an 8-bit ISRC data in the ISRC; It is composed of an 8-bit private header length, 16-bit first access unit pointer, 6-byte audio data information (ADI), and 0 to 7 stuffing bytes.

The ADI is: an 8-bit forward access unit search pointer (an address one second ahead can be read during compression)
An 8-bit backward access unit search pointer (used to read the address one second later); an audio sampling frequency fs1 of a 4-bit group "1"; and a 4-bit group "2". Audio sampling frequency fs2, 4 bit reserved area, 4 bit multi-channel type, 3 bit reserved area, 5 bit channel allocation information, 8 bit dynamic range control It consists of information.

Next, the processing of the DVD audio formatting circuit 8 will be described with reference to FIG. First, each time data is input, it is determined whether the start time (first half) or the second half position of the audio pack is present (step S1). If the start time is reached, the data counter DC is set to start counting (step S2). ), And then reset the management data of the scramble setting flag Fsc (step S3)
Next, the process proceeds to step S4. On the other hand, if it is not the start time in step S1, the process proceeds to step S4, and the scramble setting flag Fsc is determined.

Then, in step S4, if "scramble is set", it is determined whether or not the count value of the data counter DC is N or more (step S5). The management data of the scramble setting flag Fsc is set (step S6), and then the process proceeds to step S7. Here, as an example, if the audio data in one pack is 2800, M = 24 bits, and the audio data in one pack is 1800 bytes, the count value of the data counter DC in the half pack is 150 at the maximum.
N = 32. On the other hand, if “scramble setting is not performed” in step S4 and if the count value of the data counter DC is not equal to or more than N in step S5, the process proceeds to step S7. In step S7, it is determined whether the first half or the second half of the audio pack is completed.
If not, the process returns to step S1. If it has, the process proceeds to step S8. In step 8, it is determined whether or not the entire pack has been completed. If not, the process ends. Then, the scramble setting flag Fsc is set in the physical information section (FIG. 6 described later) based on the management data of the scramble setting flag Fsc.

The scramble setting flag Fsc
May be set not only in the physical information section but also in the ADI holding area described above. By doing so, the setting flag is set doubly, and the silent section can be detected using either of them, so that the convenience of performing various decoding can be realized.

When the text data accompanying the audio data is also stored, the text data is formatted into a text data pack (not shown) by the DVD audio formatting circuit 8 without being scrambled.

The audio data compression PCM according to the DVD audio standard employs a lossless compression method. However, the compression method may be a lossy compression method employed by MPEG, or may be another compression method. Not something.

The data thus formatted by the DVD audio formatting circuit 8 is supplied to an output terminal, and is output to, for example, a D
It is recorded on a VD audio disk or a memory device, or transmitted via a satellite broadcast transmitter (not shown) or the Internet. In data distribution, output data is further subjected to a specific encryption (distribution encryption).

FIG. 6 shows a data structure at the time of transmission generated by the DVD audio format circuit 8. As shown in FIG. 3A, the data is composed of a common header area and each content area. The common header area includes a player ID area, a scramble key area,
It is composed of a title information area, a content set number area, a use area information area, a transfer prepaid area, and a transfer history area.

The player ID area is an area for storing an ID for confirming whether or not the user terminal is legitimate. The player ID is first sent from the data transfer destination to the data transfer source. That is, when the mobile terminal 40 receives data from the installation terminal 41, the player ID of the mobile terminal 40 is transmitted from the mobile terminal 40 to the installation terminal 41. When the portable terminal 46 receives data from the portable terminal 40, the player ID of the portable terminal 46 is transmitted from the portable terminal 46 to the portable terminal 40.

The scramble key area is an area for storing the above-mentioned encrypted scramble key used as a secret key in the encryption processing. The title information area is an area for storing title information composed of a character string whose contents can be identified. The total number of content sets stored in the content area is stored in the content set number area. The use area information area in this area stores an area name obtained by dividing the whole country into a plurality. In the case of Japan, Kanto, Kansai, Kyushu,
For example, Hokkaido, etc., in the case of the world, use the country name.
The transfer prepaid area stores content sales information (value).

The transfer history area contains a content ID.
(Hereinafter, referred to as CID) area, a transfer count area, and a transfer date and time area. The number of transfers refers to the number of times data has been transferred from the portable terminal 40 on the transmitting side to the portable terminal 46 on the receiving side, and the transfer date and time refers to the date and time at which the transfer was performed.

FIG. 6B shows a detailed data structure of each content area. As shown in the figure, the content area includes a content header area and a content data area following the content header area. The content header area includes a content ID area, a provider ID area, a player ID area, a transfer level flag area, and an additional information area.

The company ID area stores a company ID, which is an identification code assigned to each installation terminal that receives distribution data. The transfer level flag area stores a transfer level flag which is a type of transfer rate.
The additional information area includes TOC (Total Of Co).
tents) is stored. TOC is
This is a table of contents in which address information for so-called song start and performance time are recorded. The TOC may be stored in the common header or in both the common header and the content header.

In the content data area, for example, a physical information section according to the DVD audio standard described above, audio management information (AMG), a scrambled A pack of the compressed PCM shown in FIG. A content set including an audio title in which text data having a similar data structure is combined is stored.

Next, the reproducing means 40A and 46A in the user terminal device will be described with reference to FIG. The input data stream reproduced from the storage unit 23 in the device is:
The distribution code is decrypted by the data changing unit 24, deformatted by the DVD audio formatting circuit 11, and separated into scrambled audio data, player ID data, and a scramble setting flag Fsc. Further, scramble key data (encryption key data) is read from the scramble key area, and decrypted by the encryption key data decryption unit 11a using the ID read from the memory device ID 23a in the storage unit (memory device) 23. You. Therefore, if the terminal is not a legitimate user terminal configured with a storage unit having a memory device ID, the encryption key data cannot be decrypted and the scramble cannot be decrypted. The scramble setting flag Fsc is applied to a control terminal of the switch circuit 15. P
The N code generator 12 generates a PN code corresponding to the key data supplied from the data format circuit 11 and the initial value supplied from the initial value generation circuit 18 for each clock, and the scrambled audio data is converted to an EX-code. OR circuit 1
3, the exclusive OR is calculated with the PN code and descrambled. In addition, the generation algorithm of this PN code is changed by the key data, and the generated code is not of fixed length, but is generated functionally and continues infinitely.
Initialized with the initial value. The initial value generating circuit 18 generates an initial value based on sector information from the system control circuit 20 to which the reproduction position information of the content comes.

The descrambled audio data is applied to one input terminal b of the switch 15, and the unscrambled audio data is applied to the other input terminal a of the switch 15. Then, based on the scramble setting flag Fsc, the switch 15
EX-OR in a section that is not a silent section or a section close to silent
The output signal of the circuit 13 is selected. On the other hand, in a silent section or a section close to silent section, an output signal of a through path is selected and D
The signal is converted into an analog audio signal by the / A converter 16. Although not shown, the text data pack is separated by the DVD audio reformatting circuit 11 and output as character information via the text data generator 17.

Electronic money corresponding to the content fee of the received content data is paid from the electronic wallet 19. If the TOC is recorded in the TOC memory 18, a high-speed content search stored in the storage unit 23 can be performed. When the user designates the first content set, the second content set,..., The Nth content set from the operation hand unit 21, the TOC refers to the corresponding location of the TOC via the system control unit 20. , The address, the reproduction time, and the like, to start the access and to display the reproduction time. Since there is no need to scan the header of the content, there is no so-called waiting time, and access is easy, so that it can be effectively used for high-speed scanning (intro scan). When the terminal shown in FIG. 7 is used for transfer (transmission), the content stored in the storage unit 23 is decrypted by the data change unit 24 and transmitted from the data transfer interface 25. When the terminal in FIG. 7 receives a content from another terminal, the content is encrypted by the data changing unit 24 before being stored in the storage unit 23.

Next, an encoding device according to a second embodiment and a reproducing means in a user terminal will be described with reference to FIGS. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted, or the description is omitted. FIG. 8 is a diagram showing an encoding device 43B according to the second embodiment. In FIG. 8, the input stereo audio signals of two channels L and R are A / D.
The converter 1 converts the data into M-bit digital data for each channel, and then applies the M-bit data of each channel in parallel to one input terminal of one of the M EX-OR circuits 2. Also, a determination unit (not shown) determines whether the memory device ID transmitted from the user terminal is a legitimate ID, and when the memory device ID is determined to be a legitimate ID, matching information is output to the random number generator 9a. You. The random number generator 9a outputs a scramble key to the PN code generator 3 based on the coincidence information. In the PN code generator 3, one word is given as an initial value for each sector by this scramble key, and a PN code of the number of words corresponding to M bits is generated by a periodic pulse, and the EX-OR circuit 2 is connected in parallel to each word. Output to the other input terminal. Therefore, exclusive OR is performed with the PN code and scrambled. The scrambled audio data is applied to one input terminal of the switch 4, and the audio data converted by the A / D converter 1 is applied to the other input terminal of the switch 4. The switch 4 is switched by a scramble setting flag Fsc generated based on detection of a silent section described later, and the data selected by the switch 4 is applied to the DVD audio formatting circuit 8a.

Also, if the memory device ID is the function generator 1
0a. The function generator 10a generates, for example, a hash value corresponding to the memory device ID, and the hash value is supplied to the encryption unit 10 together with the scramble key generated by the random number generator 9 described above. The encryption unit 10 encrypts the scramble key based on the hash value, and supplies the encrypted scramble blue to the DVD audio formatting circuit 8. In the second embodiment, the encrypted scramble key (encryption key) is stored in advance in the distribution encryption key area in the common header shown in FIG. The data stored here is used.

FIG. 9 is a block diagram showing a second embodiment of the reproducing means 40B, 46B in the user terminal. In the figure, the data stream reproduced from the storage unit 23 in the apparatus is decrypted for distribution,
The D audio deformatting circuit 11a separates the data into scrambled audio data and a scramble setting flag Fsc. The scrambled audio data is applied to the control terminal a of the switch circuit 15 and EX- It is supplied to one of the OR circuits 13. Also, the scramble setting flag Fsc
Is supplied to the control terminal b of the switch circuit 15.

At the same time, the ID of the memory device ID 23a in the storage unit 23 and the encrypted scramble key stored in the common header are read out, and the ID is sent to the same function generator 26 as provided on the encoding side. The hash value is supplied to generate a hash value, and this hash value is supplied to one of the decryption units 27. Also, the decryption unit 27
The other is supplied with an encrypted scramble key, and the encrypted scramble key is decrypted by a hash value to be a scramble key before encryption. And this scramble key is P
It is supplied to one of the N code generators 12.

The PN code generator 12 generates a PN code corresponding to an initial value supplied from the system control unit 20 based on the sector information for each clock, and generates a descrambling signal according to the scramble key. And EX
The exclusive OR is obtained between the descrambling signal and the scrambled audio data in the OR circuit 13 and descrambled. Thereafter, in the same manner as in the first embodiment, the switch 15 is switched by the scramble setting flag Fsc, and the EX-OR circuit 13 is operated in a non-silent section or a non-silent section.
Is selected, and in a silent section or a section close to silent section, an output signal of a through path is selected.

Therefore, according to the second embodiment, a function generator serving as a common secret key generated based on the memory device ID is provided on each of the encoding side and the user terminal side, and this secret key is directly transmitted and received. The secret key is not stolen during transmission.

Next, FIG. 10 shows a third embodiment of the encoding device. In this embodiment, the memory device ID is directly used as the scramble key. Therefore,
The scramble determination unit 9, the random number generator 9a, and the encryption unit 10 in the encoding device shown in FIGS. 2 and 9 are not required, and the memory device ID itself is formatted instead of the encrypted scramble key.
At the time of data transmission, the above-described memory device ID is stored in the common header in place of the encrypted scramble key in the common header. As the reproducing means in the user terminal, instead of the decryption unit 11a of the encryption key data in the reproducing means of FIG. 7 shown as the first embodiment,
For example, a memory device ID confirming unit is provided, and a memory device ID transmitted from the encoding device side,
Memory device ID 23a of the storage unit 23 in the reproducing means
Are compared with each other, and when they match, the matched memory device ID itself is output to the PN code generator 12 as key data. In the case of the third embodiment, the configuration on the encoding side is particularly simplified.

In the above embodiment, the scramble system based on the CSS system has been described. However, another scramble system such as a chaos function system may be used. In the above embodiment, the data structure has been described using DVD audio. However, this is an example of the data structure, and may be, for example, a data broadcasting transmission protocol (typified by the MHEG standard) used for multimedia services. However, the present invention is not limited to this.

[0052]

As described above, according to the present invention, even when pay content data including at least audio data is transmitted, a silent section or close to silent is finely performed for each partial data of audio data having a predetermined data length. Since the sections are detected and the audio data is not scrambled in those sections, the scramble code is known when the exclusive OR of the audio data and the scramble code is obtained, or when the chaos function is used, It is possible to prevent the chaos function from being known. Further, in particular, the memory device of the user terminal can be removed and mounted on another user terminal.

[Brief description of the drawings]

FIG. 1 is a block diagram conceptually showing an entire system for performing transmission and reception to which the present invention is applied.

FIG. 2 is a block diagram showing a first embodiment of a transmitting-side encoding device according to the present invention.

FIG. 3 is an explanatory diagram showing reference data of FIG. 2 in detail;

FIG. 4 is an explanatory diagram showing a format of an audio pack of a DVD audio disc.

FIG. 5 is a flowchart showing processing of a DVD audio formatting circuit in the encoding device.

FIG. 6 is a diagram showing a data structure at the time of transmission.

FIG. 7 is a block diagram showing a first embodiment of a reproducing unit in the user terminal according to the present invention.

FIG. 8 is a block diagram showing a second embodiment of the encoding device on the transmission side according to the present invention.

FIG. 9 is a block diagram showing a second embodiment of the reproducing means in the user terminal according to the present invention.

FIG. 10

[Explanation of symbols]

2 EX-OR circuit (constitutes scramble means by exclusive OR with PN code generator 3) 3, 12 PN code generator 5, 14 Inverter (other scramble means) 6L, 6R Silence section detector ( 7 OR gate 8, 8a DVD audio formatting circuit (formatting means) 13 EX-OR circuit (descramble by exclusive OR together with PN code generator 12) Means are constituted.) 19 Electronic wallet 40, 46 User portable terminal 40A, 40B, 46A, 46B Reproducing means 41 Store installation terminal 43 Content center 43A, 43B, 43C Encoding device 45 Communication satellite

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme coat ゛ (Reference) H04N 7/173 610 H04N 7/167 Z F-term (Reference) 5C064 BA07 BB02 BC17 BD08 BD09 CA12 CA16 CB03 5J104 AA01 AA33 AA41 DA04 JA04 NA35 NA36 PA00 PA07 PA11 5K030 GA15 HA08 HB01 HB08 HB16 JA05 JL02 KA04 KA07 KA08 KA17 LA06 LD19 LD20 LE12 LE14

Claims (4)

[Claims] 1. A content data distribution system having at least a content center for distributing content data including at least audio data, and a user terminal for requesting the distribution of the content data, and connecting these via communication means for data distribution. A means for detecting identification information uniquely assigned to the memory device from a memory device built in the user terminal; and a silent section for each partial data length of audio data having a predetermined data length. A scrambler that scrambles the audio data according to identification information uniquely assigned to the memory device in a section that is not the silent section, and does not scramble the audio data in the silent section. Scrambling Have been or and means for formatting the data structure and a flag indicating whether the audio data and the scramble is not scrambled, the encoding apparatus of the content data with. 2. Content data delivery system comprising at least a content center for delivering content data including at least audio data, and a user terminal for requesting the delivery of the content data, and connecting these via communication means to deliver the data. A recording medium used in a system, comprising detecting a silent section for each partial data length of audio data having a predetermined data length, and detecting the silent section in accordance with identification information uniquely assigned to a memory device built in the user terminal. In a non-interval section, the audio data is scrambled in a predetermined manner, and in the silent section, the audio data is not scrambled. But Recording medium for recorded content data. 3. A content data delivery method in a content data delivery system having at least a content center delivering content data including at least audio data and a user terminal requesting delivery of the content data, Comprises at least a common header in which an ID of the user terminal is set, and a content set, wherein the content set detects a silent section for each partial data length of audio data having a predetermined data length, The audio data is scrambled by a predetermined method in a section that is not the silent section in accordance with identification information uniquely assigned to a memory device incorporated in the memory section. The method of distributing content data, wherein the data and a flag indicating the presence or absence of Le is or unscrambled the audio data and the scramble is distributed are arranged. 4. A content data delivery system comprising at least a content center for delivering content data including at least audio data, and a user terminal for requesting the delivery of the content data, and connecting these via communication means to deliver content data. The system is used for detecting a silent section for each partial data length of audio data having a predetermined data length, and based on a scramble key generated according to identification information uniquely assigned to a memory device built in the user terminal. In the non-silent section, the audio data is scrambled in a predetermined manner, and in the silent section, the audio data is not scrambled. A user terminal for descrambling and reformatting a data structure having the following structure, wherein in a section other than the silent section, the audio data is descrambled according to identification information assigned to the memory device, A user terminal having means for not descrambling the audio data based on the flag.