JP2000286835A - Method for scrambling and descrambling contents data, encoder, 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 EX-OR circuit 2 exclusively ORs audio data with a PN code generated based on a player ID for a voiced period in an encoder 43A so as to scramble the audio data and a DVD audio formatting circuit 8 selects an output signal of a through-path for a non-voice period or a period close thereto. An EX-OR circuit 13 of a descrambler side exclusively ORs the audio data scrambled for a voice period with the PN code to descramble the audio data, and an output signal of the through-path for a non-voice period or a period close thereto is selected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a content data scrambling, descrambling method, encoding device, recording medium, distribution method, and 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, distribution in such an example system is charged, and content data to be charged is scrambled by a predetermined method due to copyright management problems. As an example of the scrambling method, there is a method used for a DVD (digital video disk, digital versatile disk). In this method, video data is scrambled by a method called CSS (content scrambling 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. Content data scrambling, descrambling method that can prevent the scrambling code and chaos function used when being known,
An object is to provide an encoding device, a recording medium, and a user terminal.

[0007]

The present invention, in order to achieve the above object, comprises the following 1) to 5). 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 Detecting at least a silent section of the audio data, and scrambling the audio data in a predetermined manner in a section that is not the silent section according to a predetermined scrambling key, and not scrambling the audio data in the silent section. Transmitting the scrambled or unscrambled audio data to a requesting user terminal; and
Descrambling the audio data in a predetermined manner in a section that is not the silent section, and not descrambling the audio data in the silent section.
A method for scrambling and descrambling content data.

2) 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 at least a silent section of audio data, and scrambling the audio data in a predetermined manner in a section that is not the silent section according to a predetermined scramble key, and in the silent section, Means for scrambling audio data without scrambling, and means for formatting the scrambled or unscrambled audio data and the scrambled key into a data structure having an encrypted key. Encoding device Ceiling data.

[0010] 3) Distribution of content data which has 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 which is connected by communication means for data distribution. A recording medium used in the system, wherein at least a silent section of audio data is detected, and the audio data is scrambled in a predetermined manner in a section that is not the silent section according to a predetermined scramble key, and the audio data is scrambled in the silent section. A recording medium for content data in which a data structure having the scrambled or unscrambled audio data is recorded without scrambling data.

[0011] 4) 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, Consists of at least a common header in which the ID of the user terminal is set, and a content set. The content set detects at least a silent section of audio data, and according to a predetermined scramble key, in a section other than the silent section, The audio data is scrambled in a predetermined manner, and the audio data is not scrambled in the silent section, and the scrambled or unscrambled audio data and the scramble key are not scrambled. The method of distributing content data, wherein the data and a key encrypted is distributed are arranged.

5) 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. Used in the system, at least a silent section of the audio data is detected, the audio data is scrambled by a predetermined method in a section other than the silent section according to a predetermined scramble key, and the audio data is not scrambled in the silent section. A user terminal for descrambling and de-formatting the data structure of the scrambled or unscrambled audio data and the scramble key having an encrypted key, In descrambling the audio data in a predetermined manner, a means that does not descramble the audio data the input in the silent section,
User terminal having.

[0013]

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 I).
D. ). Each content also has a unique identification code (hereinafter, referred to as a content ID). The mobile terminal 40 requests the store setting terminal 41 to transmit the content data. At that time, the mobile terminal 40
Transmits the content ID and the player ID.

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 transmission data described above that the transmission of the content data has been requested from the mobile terminal 40.

The charging 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 transmit 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 can be carried freely. ) Can be played and enjoyed.

As shown in FIG. 2B, 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 convenience, but both have both functions of transmitting and receiving. 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 encoding device on the transmitting side. 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, audio signals of two stereo channels, L and R, are converted into M-bit digital data for each channel by an A / D converter 1, and then M M-bit data of each channel are converted into M digital data in parallel. Is applied to one input terminal of one of the EX-OR circuits 2. P
The N code generator 3 generates a PN code in which one word is M bits by the scramble key determined by the scramble key determination unit 9 according to the player ID, and outputs the PN code to the other input terminal of the EX-OR circuit 2 in parallel. Therefore, the audio data is exclusive-ORed 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 the scramble change flag Fsc, and the data selected by the switch 4
It is applied to the D audio formatting circuit 8. The data of the player ID and the scramble key data (encryption key data) encrypted by the encryption unit 10 using the player ID are also applied to the DVD audio formatting circuit 8.

Further, the audio signals of the two channels L and R converted by the A / D converter 1 are applied to silent interval detectors 6L and 6R, respectively, based on the reference data shown in detail in FIG. A section close to silence is detected. As shown in FIG. 3, the reference data includes N consecutive M bits of “+0” or “−”.
Is a code for determining whether or not the number is "0". N is, for example, the number of words of the scramble serial code = 1.
It is half of 28. This detection signal is logically ORed by the OR gate 7 to detect a silent section or a section close to silent on either channel, and a scramble change flag Fsc
Is applied to the control terminal of the switch 4. The output signal of the EX-OR circuit 2 is selected by the switch 4 in a section that is not a silent section or a section close to silent, and an output signal of a through path is selected in a section that is silent or close to silent.

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, which 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 comprises: a 1-bit audio emphasis flag, a 1 + 2 bit reserved area, a 4-bit downmix code, and a 4-bit group “1” quantization word length “1”.
And the quantization word length “2” of the 4-bit group “2”
A 4-bit audio sampling frequency fs1 of group "1"; a 4-bit audio sampling frequency fs2 of group "2"; a 4-bit reserved area; and a 4-bit multi-channel type. , 3 bits of reserved area, 5 bits of channel allocation information, and 8 bits of dynamic range control 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 or not it is the audio pack start time (step S1). If it is the start time, the data counter DC is set to start counting (step S1).
2) Then, the management data of the scramble change flag Fsc is reset (step S3), and 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 to determine the scramble change flag Fsc.

If "scramble change" is found in step S4, it is determined whether or not the count value of the data counter DC is equal to or more than N (step S5). The management data of the scramble change flag Fsc is set (step S6), and the process proceeds to step S7. Here, as an example, if the audio data in one channel is 2800 bits, M = 24 bits, and one pack is 1800 bytes, the data counter DC
Has a maximum value of 300, but N = 64.
On the other hand, in step S4, "there is a scramble change"
If not, in step S5 the data counter DC
If the count value is not more than N, the process directly proceeds to step S7. In step S7, it is determined whether or not the audio pack has ended. If not, the process returns to step S1. On the other hand, if the audio pack has ended, this process ends. Then, the scramble change flag Fsc is set to control the switch 4 based on the management data of the scramble change flag Fsc.

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, a physical information section conforming to the DVD audio standard, audio management information (AMG), a scrambled A pack of the compressed PCM shown in FIG. 4, for example, and similar data A content set including an audio title in which structured text data 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 deformatting circuit 11, and separated into scrambled audio data and player ID data. Further, the encryption key data is read from the above-mentioned scramble key area, and the decryption unit 11a of the encryption key data decrypts the player ID2.
Decryption is performed using the player ID read from Step 2.
Therefore, if the terminal is not a legitimate user terminal, the encryption key data cannot be decrypted and the scramble cannot be decrypted. The PN code generator 12 generates a PN code corresponding to the scramble key data, and the scrambled audio data is exclusive-ORed with the PN code by the EX-OR circuit 13 and descrambled.

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. The audio data L and R are applied to the silent interval detectors 14L and 14R,
A silent section or a section close to silent is detected based on the reference data shown in FIG. This detection signal is logically ORed by the OR gate 14A to detect a silent section or a section close to silent on either channel, and outputs it as a scramble change flag Fsc. Then, based on the detected scramble change flag Fsc, the switch 15
As a result, the output signal of the EX-OR circuit 13 is selected in a section that is not a silent section or a section that is not close to silence, and D
The signal is converted by the / A converter 16 into an analog audio signal. On the other hand, in a silent section or a section near a silent section, an output signal of a through path is selected. 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.

Therefore, according to the present embodiment, the audio data is not scrambled in the silent section on the encoder side, so that when the exclusive OR of the audio data and the scramble code is obtained, the scramble code is known. Can be prevented.

The detection of a silent section is not limited to the above embodiment. Information about whether or not a scramble has been entered in the above-described physical information section, and whether or not the section is a silent section is determined by referring to this information. You may make it detect. Further, the determination of the silent section is not limited to the above embodiment, and it may be determined whether or not the data of M bits is “+0” or “−0”. In the present embodiment, the scramble method based on the CSS method has been described, but another scramble method such as a chaos function method may be used. Also,
In the above embodiment, the data structure is described using DVD audio, but this is an example of the data structure, and may be, for example, a data broadcasting transmission protocol (MPEG standard is representative) used for a multimedia service. However, it is not limited to this.

[0046]

As described above, according to the present invention, even when paid content data including at least audio data is transmitted, at least a silent section of the audio data is detected, and the audio data is scrambled in the silent section. Since it is not performed, it is possible to prevent the scrambling code from being known when the exclusive OR of the audio data and the scramble code is obtained, and to prevent the chaos function from being known when the chaotic function is used. Further, since the data of the encrypted scramble key for descrambling in a predetermined format is stored together with the audio data, the management becomes easy.

[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 an 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 the DVD audio standard.

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 an embodiment of a reproducing unit in the user terminal according to the present invention.

[Explanation of symbols]

2 EX-OR circuit (constitutes scramble means by exclusive OR together with PN code generator 3) 3,12 PN code generator 6L, 6R, 14L, 14R Silence section detector (silence together with OR gate 7) 7, 14A OR gate 8 DVD audio formatter (formatter) 13 EX-OR circuit (along with PN code generator 12, constitutes a descrambling unit based on exclusive OR) 19 Electronic wallet 40, 46 User portable terminal 40A, 46A Reproducing means 41 Store installation terminal 43 Content center 43A Encoding device 45 Communication satellite

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 5C053 FA13 FA24 GB11 GB40 JA07 KA08 KA21 KA25 5C064 CA12 CA14 CA16 CB08 CC01 CC04 5J104 AA33 CA02 JA04 PA04 PA05

Claims (5)

[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. Detecting at least a silent section of the audio data, scrambling the audio data in a predetermined manner in a section other than the silent section according to a predetermined scrambling key, and not scrambling the audio data in the silent section. Transmitting the scrambled or unscrambled audio data to the requesting user terminal; and in the user terminal, descrambling the audio data in a predetermined manner in a section other than the silent section. Scrambling and descrambling the content data in the silent section. 2. 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 at least a silent section of audio data, and scrambling the audio data by a predetermined method in a section that is not the silent section according to a predetermined scramble key, and in the silent section, Means for scrambling the audio data without scrambling; and means for formatting the audio data into a data structure having the scrambled or unscrambled audio data and the scrambled key encrypted. Encoding device for tents data. 3. A content data delivery system having 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 for delivering data. A recording medium used in a system, wherein at least a silent section of audio data is detected, and the audio data is scrambled in a predetermined manner in a section other than the silent section according to a predetermined scramble key, and the audio data is scrambled in the silent section. A recording medium for content data in which a data structure having the scrambled or unscrambled audio data is recorded without scrambling data. 4. 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, Consists of at least a common header in which the ID of the user terminal is set, and a content set. The content set detects at least a silent section of audio data, and in a section other than the silent section according to a predetermined scramble key, The audio data is scrambled in a predetermined manner, and the audio data is not scrambled in the silent section, and the scrambled or unscrambled audio data and the scramble key are used. The method of distributing content data, wherein the data and a Goka key is distributed are arranged. 5. A content data distribution system comprising 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 to distribute the content data. Used in the system, at least a silent section of the audio data is detected, the audio data is scrambled according to a predetermined scheme in a section other than the silent section according to a predetermined scramble key, and the audio data is not scrambled in the silent section. A user terminal that descrambles and deformats a data structure having the scrambled or unscrambled audio data and a key in which the scramble key is encrypted, In descrambling the audio data in a predetermined manner, the user terminal having means, not descramble the audio data the input in the silent section.