JP2003198525A - Enciphering method for contents and reproducing method for enciphered contents - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an enciphering method for contents for enciphering the contents and a reproducing method for the enciphered contents. <P>SOLUTION: In the enciphering method for the contents in which a packaged enciphered stream is prepared by enciphering the stream of the contents, the method is provided with a step (S301) for dividing the contents into a plurality of contents data, a step (S302) for enciphering at least one of the plurality of divided contents data by a designated key, a step (S303) for forming a plurality of data packets by adding a header to the plurality of divided contents data and for adding key information on the designated key to the header as header information, and a step (S304) for packaging the plurality of divided data packets added with the header into one stream. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a content encryption method for encrypting content such as music and video delivered to a mobile terminal, and a method for reproducing encrypted content by the encryption method.

[0002]

2. Description of the Related Art In recent years, due to the development of network technology,
Content distribution method (system) for distributing music data and video data to mobile terminals and PCs via a network
Is provided. At present, this content distribution system should be equipped with a mechanism such that the data itself is encrypted and can be played back only when purchased in order to protect the copyright of music data and video data (content) and to earn copyright income. Is being actively conducted.

[0003]

In the above-mentioned encryption system, the contents are not illegally copied. Even if it is illegally copied, it cannot be played back without a key for decrypting the code. With such an encryption system, a user who wants to listen to music or images before purchasing can not listen to them.
This is an obstacle to using this system.

Therefore, in recent years, there is an apparatus (Japanese Patent Laid-Open No. 2001-103047) that distributes (distributes) some of the content data without encrypting it so that it can be listened to. According to this distribution device, the encrypted range is described in the header portion 902 of the file as shown in the conceptual diagram of the data stream in FIG. 9, and it is not encrypted if not purchased at the time of reproduction. When the unencrypted content data (plaintext) in the area is reproduced and purchased, the unencrypted content data (plaintext) in the unencrypted area and the encrypted area encrypted content data 1 and 2 Both data areas 901 are reproduced.

However, according to this distribution device,
Since the encrypted area is described in the header 902 at the beginning of the content, data streaming such as broadcasting,
When it is desired to reproduce the data from an arbitrary location on the content, the header information at the beginning of the file needs to be obtained in advance, which causes a problem such as having to seek from the beginning of the data.

Further, according to this distribution (distribution) apparatus, an authoring tool for describing the encrypted area in the header 902 and a process of analyzing the header at the time of reproduction are required, and complicated processing is performed at the time of producing and reproducing the content. Is required.

Therefore, the present invention has been made to solve such a problem, and a step of dividing a content into a plurality of content data and at least one of the plurality of divided content data are designated. Encrypting with a key, adding a header to each of the divided plurality of content data to form a plurality of data packets, and adding key information about the specified key as header information to the header , A step of packaging a plurality of data packets to which the header is added into one stream, so that music data in which a part of the data is encrypted can be auditioned from any place or can be reproduced normally. Method, easy creation of music data in which part of the data is encrypted, listening or normal playback And to provide a method that allows the process.

[0008]

As a means for achieving the above object, the invention described in claim 1 is a content encryption method for encrypting a content stream to create a packaged encrypted stream. At
Dividing the content into a plurality of content data (S301), encrypting at least one of the divided plurality of content data with a designated key (S302), and dividing the plurality of divided content data. A step of adding a header to each content data to form a plurality of data packets, and adding key information regarding the specified key as header information to the header (S30)
3. A method for encrypting content, comprising: 3) and packaging (S304) the plurality of divided and added header data packets into one stream. In the content encryption method of creating an encrypted file in which a file of content is encrypted and packaged, a method of dividing the content into a plurality of files (S701) and the plurality of divided files Encrypting at least one of the files with a designated key (S702), adding the file reproduction order as the file name, and designated key information to each of the plurality of files (S703), A step of packaging a plurality of files into a single file (S704). A method for encrypting content, wherein the invention described in claim 3 is the method for reproducing encrypted stream, which reproduces the encrypted stream created by the method for encrypting content according to claim 1, The step of cutting out and dividing the data packet from the packaged encrypted content (S40)
1), the step of decrypting the cut-out data packet using the specified key based on the header information of the data packet (S402), and the decrypting step (S402). And a step (S403) of reproducing the content, which provides reproduction of encrypted content from any location of the content data, and the invention described in claim 4 provides A method of playing back an encrypted file created by the content encryption method according to claim 2, wherein the packaged encrypted content is divided into a plurality of files (S801), Decrypting the divided files in the designated order using the designated key (S80) And), said decoding step (S80
And a step (S803) of reproducing the content decrypted in 2), which enables reproduction from an arbitrary file location.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The preferred embodiments of the content encryption method and encrypted content playback method of the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of a first embodiment of a content encryption method and an encrypted content reproduction method of the present invention. FIG. 2 is a conceptual diagram showing the structure of a data stream of content (music, video data) encrypted by the content encryption method of the present invention.

FIG. 3 is a flow chart showing a processing procedure at the time of content creation by the content encryption method of the present invention. FIG. 4 is a flowchart showing a processing procedure at the time of content reproduction by the encrypted content reproduction method of the present invention.

In the content encryption method and encrypted content reproduction method of the first embodiment shown in FIG. 1, the audio or video content 106 to be distributed is encrypted by the content distribution apparatus 101 and encrypted for distribution. Content 1
07 is created, distributed using a network or the like, and reproduced by the content reproduction device 108. A content stream is divided into a plurality of content data (content blocks), and the divided data data is encrypted and distributed. Particularly, an encryption method when a broadcast program, movie, etc. is encrypted and distributed. Is effective as.

The content distribution apparatus 101 has a content dividing means (step) 102 for dividing an encrypted portion and an unencrypted portion of the original content 105 into respective packets, and a content dividing means (step) 102.
Packet encryption means (step) 10 for encrypting a packet requiring encryption, out of the packets divided by, with at least one specified key
3 and packet header adding means (step) 104 for adding a header to the beginning of each packet and adding the specified key information to the header as header information for the data packet encrypted by the specified key. And a packaging means (step) 1 for packaging the packet (group) divided by the above processing into one stream.
05 and.

The content reproducing apparatus 108 searches the header portion from an arbitrary position of the encrypted content distributed by the content distributing apparatus, and cuts out the packet of the content dividing means (step) 109, and the means for cutting out the packet. An encrypted content decrypting means (step) 110 is provided for obtaining key information or the like from the header information of the packet, decrypting the encryption, and sequentially transferring the packet to the content reproducing means 111. The content reproducing means (step) 111 is a reproducing means (step) for reproducing compressed or uncompressed audio or video data.

In FIG. 2, a distribution data stream 2
01 is a diagram showing an outline of the distribution content 106 created by the content distribution apparatus 101.
A plurality of data packets are packaged in one distribution data stream. For example, the distribution data stream 201 of FIG. 2 has three data packets 204.
Further, one data packet is composed of a header area 202 and a data area 203.

Next, using the flowchart of FIG.
A content creation processing procedure in which the content distribution apparatus 101 creates distribution content will be described.

In step S301, the original content is divided into a portion requiring encryption and a portion not requiring encryption.
For example, in the case where the middle 10 seconds of the 30-second content is the unencrypted area, the first 10 seconds is the first content data, the middle 10 seconds is the second content data, and the second half is 10 seconds. Is divided into the third content data. The number of pieces of content data may be fixed or variable.

In step S302, the content data that needs to be encrypted is encrypted. In the case of the above-mentioned example, the first half (head) and the second half will be encrypted.

In step S303, header information describing the data size of the content data, encrypted / non-encrypted information, key information used for encryption, etc. is added to the beginning of the content data.

In step S304, the content divided into a plurality of data packets is repackaged into one stream.

Next, using the flowchart of FIG.
The content reproduction device 108 is the content distribution device 101.
A content playback processing procedure when playing back the encrypted content created in 1. will be described.

In step S401, when the data stream distributed from the content distribution apparatus 101 is input to the content reproduction apparatus 108, the content division means 109 searches the header area. For example, a unique ID is placed at the beginning of the header area, and the stream is read up to the portion that matches the ID.

When the header is found, the data packet is cut out based on the header information. The header information describes information such as the number of data in the data packet, information on whether encryption is applied, and key information used when decrypting the encryption.

In step S402, the encrypted content decryption means 110 decrypts the encryption based on the key information and the like described in the header of the cut out data packet.

In step S403, the decrypted content data is sequentially transferred to the content reproducing means 111. The content reproducing means 111 may be a PCM reproducing device, an MPEG video, an audio decoder or the like, but other digital data reproducing device may be applied.

As described above, according to this embodiment, the header search is started first, and the reproduction is started from the portion where the header is found. Therefore, the reproduction can be performed from the middle of the stream.

Further, different keys can be used for non-encryption, encryption, and encryption for each part of the content to be distributed, and services such as audition of encrypted content are also possible. .

Next, a second embodiment of the content encryption method of the present invention will be described with reference to the drawings. FIG. 5 shows a block diagram of the second embodiment of the present invention.
FIG. 6 is a conceptual diagram showing the structure of a content (music, video data) file distributed in that embodiment. FIG. 7 is a flow chart showing a content creation processing procedure at the time of creating content according to the embodiment. FIG. 8 is a flow chart showing a content reproduction processing procedure at the time of reproducing the content of the embodiment.

The second embodiment shown in FIG. 5 is a method of encrypting audio and video contents 506 to be distributed, creating distribution contents 507, and distributing them to the content reproducing device 507 using a network or the like. is there. The content file is divided, and the divided files are encrypted and distributed. This is an effective distribution method when distribution data is downloaded and received by a personal computer (PC).

The content distribution device 501 divides the original content 506 into a file and a content dividing means (step) 502, and a content dividing means (step) 502.
Of the files divided by, the file encryption means (step) 503 that encrypts the files that need to be encrypted with the specified key, and the addition means that adds the file reproduction order and the key information as the file name ( Step) 504, and a file packaging means (step) 505 for packaging the file group divided by the above processing into one file.

The content reproduction apparatus 508 makes the encrypted content distributed from the content distribution apparatus a plurality of files so that the encrypted content is in the same state as before being packaged by the file packaging means (step) 505. A content dividing means (step) 509 for dividing into (group), an encrypted content decrypting means (step) 509 for decrypting the files divided by the content dividing means (step) 509 in a designated file order, and The content reproduction means (step) 511 for sequentially transferring and reproducing the output of the encrypted content decryption means (step) 510 is provided. The content reproducing means (step) 511 is a reproducing means (step) for reproducing compressed or uncompressed audio or video data.

The distribution data file 601 of FIG. 6 shows an outline of the distribution content 506 created by the content distribution (encryption) device 501. One distribution data file 601 is configured by packaging a plurality of data files.

The distribution data file 601 is composed of four data files 602 to 605, and the content dividing means (step) 50 of the content reproducing apparatus 507.
When divided by 8, unencrypted data file 602 (file name (1.kno)) encrypted data file 603 (file name (2.k01)) encrypted data file 604 (file name (3.k02)) encrypted The converted data file 605 (file name (4.k01)) appears.

In this file name, the reproduction order of the files (1 or 2 or 3 etc.) and the information of the type of key used at the time of decryption of the encryption (kno, k01, or k0)
2 etc.) and this file name is used when the encrypted content decrypting means (step) 509 performs processing.

Next, using the flowchart of FIG.
A content creation processing procedure in which the content distribution apparatus creates distribution content will be described. In step S701, the original content is divided into a portion requiring encryption and a portion not requiring encryption.

For example, if the middle 10 seconds of the 30-second content is to be the non-encrypted area, the first 10 seconds is the first file, the middle 10 seconds is the second file,
Split the latter 10 seconds into a third file. At this time,
Use a file name that identifies the time series of the file.

In step S702, the file that needs to be encrypted is encrypted. Using the above embodiment, the two files, the first half (first) and the second half, will be encrypted. At this time, the extension name of each file is changed so that the key used for encryption can be identified.

In step S703, the contents divided into a plurality of files are repackaged into one file to create distribution contents. At this time,
It may be compressed using a file compression technique such as zip.

Next, using the flowchart of FIG.
The content reproduction device 507 is the content distribution device 501.
A description will be given of a reproduction processing procedure when reproducing the encrypted content created in.

At step S801, the contents packaged in a zip file or the like is decompressed by the contents distribution device and divided into a plurality of files.

In step S802, the files are decrypted in the order designated by the file name. For example, if the extension of the file name is kno, it is determined that the file has not been encrypted, and the process of transferring the file name to the content reproduction device without performing the decryption process is performed (step S803). If the extension of the file name is k01, the encryption is decrypted using the key with the key number 01, and the process of step S803 is performed.

As described above, according to the method (system) of this embodiment, it is possible to use different keys for non-encryption, encryption, and further encryption for each part of the content. . Further, since the information necessary for reproduction is provided by the file name and the like, the content creation processing and the content reproduction processing are relatively easy.

Summarizing the characteristics of the first and second embodiments described above, the content encryption method and encrypted content reproduction method (stream type) of the first embodiment are data broadcasting using a network. , It is effective as a distribution method when distributing movies, etc. because the header is inserted periodically, the production side needs an authoring tool etc., and the playback side needs to analyze the header. Will be needed. However, no matter what part of the stream is input to the playback device, if you can find the part of the header,
After that, it can be played back without any problems.

The content encryption method and the encrypted content reproduction method (file type) of the second embodiment are effective as a distribution method when distribution data is downloaded and received by a personal computer (PC). Information such as which file is encrypted with which key and in what order is played is specified by a file name, not by adding a header.

Therefore, on the content production side, for example, a music file of one song can be simply divided into a plurality of pieces, and content that can be partially viewed can be created without inserting a header or the like. Further, the reproducing side can start the reproducing process only by looking at the file name without analyzing the header or the like.

[0045]

As described above, according to the invention described in claim 1, in a content encryption method for creating an encrypted stream in which a stream of content is encrypted and packaged, the plurality of contents are Dividing the content data, encrypting at least one of the plurality of divided content data with a designated key, adding a header to each of the plurality of divided content data, and The method comprises the steps of forming a data packet and adding key information regarding the specified key as header information to the header, and packaging a plurality of data packets to which the header is added into one stream. ,
It is possible to construct a trial listening method that enables playback and trial listening from the position of an arbitrary divided data packet on the way without obtaining header information at the beginning of the entire content data. Then, if a contract is made with the distributor to purchase the content, it is possible to construct a trial listening method in which the key for the content can be obtained and the entire content can be reproduced.

According to the second aspect of the invention, in the content encryption method for encrypting a content file to create a packaged encrypted file, dividing the content into a plurality of files. A step of encrypting at least one of the plurality of divided files with a designated key, a file reproduction order as a file name, and a step of adding designated key information to each of the plurality of files, With the step of packaging multiple files into one file, when receiving, it is possible to play from the location of the divided files in the middle without receiving the file information at the beginning of the file before dividing. , You can build a listening method that allows you to listen. Also, since encryption is specified for each file, there is no need for an authoring tool to describe the encrypted area in the header or processing such as parsing the header during playback, so complicated processing is required during content production and playback. You don't have to.

Further, according to the invention described in claim 1 or claim 2, if the specified key is made to have a different kind of key for each divided data packet or for each divided file, a plurality of keys are provided. You can specify the key for each part and use it differently. For example, there is no non-encrypted part, it is composed of the part encrypted with the key for trial listening and the part encrypted with the official key purchased. The created content is created and the viewing key is distributed to the users who have contracted with the content distributor, and the user who has the key can play the part encrypted with the viewing key without any restrictions. It is possible to prevent the content for viewing from being copied.

Further, according to the invention described in claim 3, since the reproduction can be performed not from the beginning but from the middle of the stream, the application such as data broadcasting and streaming using a network is possible.

Further, according to the invention described in claim 4, at the time of reproduction, the reproduction is performed not from the beginning but from the file in the middle, only by looking at the specified file name without analyzing the header or the like. You can do it.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment of a content encryption method according to the present invention.

FIG. 2 is a diagram showing the configuration of an embodiment of a content (music, video data) data stream distributed by the content encryption method of the present invention.

FIG. 3 is a flowchart showing a processing procedure at the time of content creation by the content encryption method of the present invention.

FIG. 4 is a flowchart showing a processing procedure at the time of content reproduction by the encrypted content reproduction method of the present invention.

FIG. 5 is a block diagram of a second embodiment of the content encryption method of the present invention.

FIG. 6 is a conceptual diagram showing the structure of a content (music, video data) file distributed by the content encryption method of the present invention.

FIG. 7 is a flowchart showing a processing procedure at the time of content creation by the content encryption method of the present invention.

FIG. 8 is a flowchart showing a processing procedure at the time of content reproduction by the encrypted content reproduction method of the present invention.

FIG. 9 is a diagram showing a data configuration of an example of content (music, video data) data distributed by a conventional content encryption method.

[Explanation of symbols]

101, 501 Encrypted content distribution device 102, 502 Content division means (division step) 103 Packet encryption means (encryption step) 104 Packet header addition means (addition step) 105 Packet packaging means (packaging step) ) 106,506 Original content 107,507 Content for distribution 108,508 Content reproduction device 109,509 Content division means (step of division) 110,510 Encrypted content decryption means (step of decryption) 111,511 Content reproduction means (reproduction) Step 201) Distribution data stream 202 Header area 203 Data area 204 Data packet 503 File encryption means (encryption step) 504 File name addition means (addition) 505 file packaging means (packaging step) 601 distribution data file 602 non-encrypted data file (1.kno) 603 encrypted data file (2.k01) 604 encrypted data file (3.k02) 605 Encrypted data file (4.k01)

Claims (4)

[Claims] 1. A method of encrypting a content for encrypting a stream of a content to create an encrypted stream, the method comprising: dividing the content into a plurality of content data; At least 1
A plurality of data packets by adding a header to each of the divided plurality of content data to form a plurality of data packets, and key information about the designated key as header information. A method for encrypting content, comprising: a step of adding to a header; and a step of packaging a plurality of data packets to which the header is added into one stream. 2. A content encryption method for creating an encrypted file by encrypting a package of content files to create an encrypted file, the method comprising: dividing the content into a plurality of files; and at least one of the plurality of divided files. Encrypting one of the files with a designated key, adding a file reproduction order as a file name, and designated key information to each of the plurality of files, and packaging the plurality of files into one file. A method for encrypting content, comprising: 3. A method of playing back an encrypted content, which plays back an encrypted stream created by the content encryption method according to claim 1, wherein the data packet is cut out and divided from the packaged encrypted content. A step of decrypting the cut out data packet using the specified key based on header information of the data packet; and a step of reproducing the content decrypted by the decrypting step. And a method of reproducing encrypted content, wherein the content can be reproduced from any location of the content data. 4. A method of playing back an encrypted file created by the content encryption method according to claim 2, wherein the packaged encrypted content is divided into a plurality of files. And a step of decrypting the divided files in the designated order using the designated key, and a step of reproducing the content decrypted by the decrypting step. A method for reproducing encrypted content, characterized in that the content can be reproduced from.