JP2000163350A - Data distribution method and data distribution device - Google Patents

Abstract

(57) [Summary] [Problem] To maintain integrity during distribution. SOLUTION: A data file requested by a terminal is encoded in a predetermined format, and a data portion for transmission is generated by using a header portion including information for decoding the encoded data and the encoded data, Distribute the data file to the requesting terminal. Unless the encoded data is decoded, the original data file cannot be used, and the integrity during distribution can be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data distribution method and a data distribution device, and more particularly, to a data distribution method and a data distribution device for distributing a data file such as a moving image, a still image, and a sound via a network.

[0002]

2. Description of the Related Art In recent years, with the spread of data processing devices such as personal computers and the development of communication infrastructure such as the Internet, services for distributing data files such as moving images, still images, and sounds via networks have been put into practical use. For example, a desired image file can be downloaded by accessing an image server storing a large number of image files.

[0003]

However, in the above-mentioned conventional service, BMP (bitmap) or GMP
Since image files stored in formats such as IF (CompuServe Graphics Interchange Format) were delivered in their original format, integrity during delivery could not be maintained, and for example, sample images used for paid delivery services There was a problem that the provision of the service was inconvenient.

[0004] That is, since the sample image in the pay distribution service is for confirmation before purchase, it is desirable that the image has the same image quality as the regular image file if possible. Providing such a high-quality sample image is not realistic, since the intended purpose has been achieved and there is no need to obtain the official version until the user pays for the price. , Or by inserting the word "sample" to provide an image with a degraded image quality on purpose, but it takes time to create the sample image. Depending on how the image quality drops,
There is an inconvenience that the willingness to obtain the official version is lost.

Therefore, the present invention can maintain the integrity during distribution, and can also use a regular version of a data file for a sample, thereby reducing the time and effort of creating a sample and reducing the storage capacity of the server. An object of the present invention is to provide a data distribution device that avoids pressure and does not impair the willingness to obtain a regular version.

[0006]

According to a first aspect of the present invention, there is provided a data distribution method for distributing a data file requested by a terminal to the terminal, wherein the data file is encoded in a predetermined format. Generating a data file for transmission with a header portion including information for decoding the encoded data, and distributing the data file to a requesting terminal. And characterized in that: A data distribution method according to a second aspect of the present invention is the data distribution method according to the first aspect, wherein the header portion includes an allowable number of times of decoding. 4. A data distribution apparatus according to claim 3, wherein said data distribution apparatus distributes a data file requested by a terminal to said terminal, wherein said encoding means encodes said data file in a predetermined format; A header section including information for decoding the encoded data, generating means for generating a data file for transmission with the encoded data, and distributing means for distributing the data file to a requesting terminal. It is characterized by. According to a fourth aspect of the present invention, there is provided a data distribution device.
4. The data distribution device according to claim 3, wherein the generation unit includes an allowable number of times of decoding in the header portion. According to a fifth aspect of the present invention, there is provided a recording medium storing a program for implementing the encoding means, the generating means, and the distribution means according to the third aspect.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a server for providing an image file distribution service, and 2 denotes a network (regardless of scale, which transfers data packets corresponding to a predetermined protocol (for convenience, an IP protocol).
LAN, WAN, or Internet is fine), 3
Is a terminal equipped with application software for using the distribution service.

FIG. 2 is a block diagram of the server 1. Reference numeral 10 denotes a communication unit compatible with the IP protocol, 11 denotes a key input unit including a pointing device and a keyboard, and 12 denotes an image file by executing a predetermined server program. (Encoding unit, generation unit, distribution unit) for realizing various functions required for the distribution service of the present invention, 13 is a RAM unit used as a work area of the CPU 12, and 14 is a first unit for storing various programs including the server program. Storage unit,
Reference numeral 15 denotes a second storage unit that stores various image files for distribution, 16 denotes a display unit that displays a management screen of the distribution service, and 17 denotes a bus that connects the units.

FIG. 3 is a diagram showing the configuration of the terminal 3.
A communication unit corresponding to the P protocol; 21 is a key input unit including an OK key, a cancel key, and a cursor key;
Reference numeral 2 denotes a C that executes a predetermined client program and realizes various functions necessary for using an image file distribution service.
PU, 23 is a RAM used as a work area of the CPU 22, 24 is a ROM for storing various programs including the client program, 25 is a display for displaying a use screen of a distribution service, and 26 is a display 25
A touch panel unit 27 provided above the device is a bus connecting each unit.

The configuration shown in FIG. 3 is a so-called PDA (Pe
Although a configuration of a small portable information terminal called rsonal Digital Assistants) is shown, it is not limited to this. A laptop or desktop personal computer or workstation may be used.

FIG. 4 is a conceptual diagram showing processing of server 1 and terminal 3 in the present embodiment. As will be apparent from the following description, in the present embodiment, for example, when distributing the image file 30, the server 1 encodes the image file in a predetermined format (also referred to as encryption). The data file 31 is composed of the header information (A) including information for decoding the encoded data (B) and the encoded data (B).
1 is transmitted to the terminal side. The terminal 3 decodes the encoded data (B) based on the header information (A) of the received data file 31, and reproduces the original image file 30.

Here, when the image file 30 is used as a sample image, the header information (A) can include the number of times of reproduction of the image. The number of times of reproduction regulates the number of times of decoding in the terminal 3. For example, if the number of times of reproduction is set to one, only one reproduction of the image file 30 is permitted, so that image confirmation can be performed prior to obtaining a regular version (unlimited number of times of reproduction).

Moreover, since the image quality is the same as the regular version,
Since it does not impair the willingness to obtain and does not need to separately hold an image for a sample, the labor can be reduced and the server 1
Storage capacity does not squeeze.

FIG. 5 is a structural diagram of the data file 31 transmitted from the server 1 to the terminal 3.
1 is composed of a header part and a data part. DATA
Is the encoded data stored in the data part, and the field configuration of the header part is as follows.

<ID>: (identification code field) A code indicating the original file format of the encoded data DATA is stored. FIG. 6 shows the code list. According to this list, for example, ID is 1 (000 in binary code).
If 1) is stored, the original file format is BM
This is a P image (a file with the extension “bmp”). <CV>: (encoding format field) encoded data DA
A code indicating the encoding format of the TA is stored. For example,
If 1 (0001 in binary code) is stored, it indicates that the encoding is performed by an exclusive OR operation,
Alternatively, when 2 (0010 in binary code) is stored, it indicates that the data is encoded (encrypted) according to DES (Data Encryption Standard). <CD>: (Key data field) The key code used for encoding is stored. For example, if the encoding format is an exclusive OR operation, the operated code is stored, or
In the case of DES, a secret key code is stored. <LN>: (data length field) coded data DAT
The data length (or file size) of the original data of A is stored. <OC>: (optional field) This field is used as needed. In the present embodiment, as shown in FIG. 7, storage of information (MT) indicating the function type of the terminal and permission for decoding are allowed. Used to store the number of times (CT). The function type (MT) of the terminal is, for example, the reproduction performance of an image file (monochrome, color, and the number of display pixels). If 1 (0001 in binary data) is set here,
Indicates a monochrome display of 192 × 132 pixels.
Also, the allowable number of decodings (CT) is set to a small number (for example, one) when the encoded data DATA is used for sampling. <CR>: (Checksum field) Checksum data of the header part is stored.

FIG. 8 is a flowchart of a program executed by the server 1. When you start this program,
First, the process waits for a transmission request from a terminal connected to the network 2 (hereinafter, referred to as “terminal 3”) (S10). When the transmission request is received, the requested image file (BM here) is received.
P file) from the second storage unit 15 (S
11), its file size (data length: 1K here)
B) (S12). Next, an encoding method designated in advance (here, exclusive OR operation) is set (S13), and key data required for the encoding is generated (here, 01010101) and set ( S14). Next, using the set encoding method and key data, the image file read in step S11 is encoded (S15), and when the encoding is completed (S16), the encoded data (DATA) and decoding are performed. Data file 31 for transmitting necessary information etc.
Is generated (S17). Then, the data file 31 is transmitted to the requesting terminal 3 (S18), and after the transmission is completed (S1).
9) Return to the state of waiting for a transmission request.

The contents of the data file 31 generated in step S17 are as follows in this example. <ID>: 0001 indicating the BMP file format is stored. <CV>: 0001 indicating an exclusive OR operation is stored. <CD>: 0101101 is stored. <LN>: 1 KB is stored. <OC>: Not mentioned in the above flowchart,
If the request from the terminal 3 is a request for a sample image, C
In T, n (n is an appropriate number of times that use as a sample image is permitted) is stored, and in MT, the display capability code 00001 (monochrome display of 192 × 132 pixels) of the terminal 3 is stored. <CR>: The checksum code of the header part including the above information is stored.

FIG. 9 is a flowchart of a program executed by the terminal 3. When this program is started, first, the validity of the data file 31 sent from the server 1 is checked. For example, when the header information does not exist (NO determination in S20), it is determined that the data is not valid, and the subsequent processing is not performed. The presence or absence of header information is determined by I
This may be performed based on whether or not the code in FIG. 6 is included in the D field. If an invalid code not found in the list is detected, it is assumed that header information does not exist.

When the header information exists, the data file 31 from the server 1 is received to the end (S21). When the reception is completed (S22), the CV (encoding method), the CD ( Key data) and LN (data length) are extracted (S23 to S25). If a valid code (for example, 0001) is stored in the OC header, the MT (terminal function) of the OC and the CT
(Reproduction count) is also extracted (S26). Next, CV and CD
Based on the encoded data DAT of the data file 31
A is decrypted (S27), and when decryption is completed (S2
8), CT (reproduction count) is decremented by 1 (S29), and after performing terminal-specific processing (S30) according to MT (terminal function),
The decrypted playback data is output to the display unit 25 (here, the image data is in the BMP format).

As described above, according to the present embodiment, the data requested by the terminal 3 (for convenience, an image file) is encoded in a predetermined format, and the encoded data (DA
TA), and a header section including decoding information (CV, CD) and the like necessary for decoding the encoded data, to form a data file 31 for transmission. Since the data file 31 is transmitted to the terminal 3, the original image file cannot be used unless the data file 31 is decrypted, so that data integrity can be maintained.

In addition, the number of times of decoding, that is, encoded data (DATA) is stored in the option field of the header section.
By setting the number of times of reproduction, the number of times of use on the terminal 3 can be restricted, and one image file can be shared between the regular version (without the number of reproductions) and the sample version (with the number of reproductions). Therefore, since it is not necessary to create a sample image again, it is possible to reduce labor and to avoid pressure on the storage capacity of the server 1, and to provide a high-quality sample image equivalent to that of the regular version. A particularly excellent effect that does not impair the motivation can be obtained.

Further, the main functions (encoding means, generating means, distribution means, etc.) of the above-described embodiment are realized by an organic connection between a hardware asset including a microcomputer and software assets such as an OS and various programs. Although the functions are realized functionally, general-purpose hardware resources can be used, and essential items indispensable for the present invention are that they are substantially concentrated in the OS and various programs. Can be said. Therefore, the present invention provides a floppy disk, MO, CD,
It includes a recording medium such as a hard disk or a semiconductor memory (not only a medium that can be put on a distribution channel itself, but also a medium that is provided on a network and provides only recorded contents).

[0023]

According to the first or third aspect of the present invention, a data file requested by a terminal is encoded in a predetermined format, and a header section including information for decoding the encoded data is provided. A data file for transmission is generated with the encoded data, and the data file is distributed to the requesting terminal. Therefore, unless the encoded data is decoded, the original data file cannot be used, and security during distribution is not performed. Sex can be maintained. According to the invention described in claim 2 or claim 4,
In the data distribution method according to the first aspect, the number of times of decoding on the terminal side can be limited because the allowable number of times of decoding is included in the header portion, and can be used for a sample, for example. Therefore, there is no need to create a separate data file for the sample, which saves labor and avoids the pressure on the storage capacity of the server. In addition, it can provide sample data of the same quality as the regular version, which impairs the willingness to obtain the regular version. Nothing.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a network configuration according to an embodiment;

FIG. 2 is a configuration diagram of a server.

FIG. 3 is a configuration diagram of a terminal.

FIG. 4 is a conceptual diagram of processing according to the embodiment;

FIG. 5 is a structural diagram of a transmission data file.

FIG. 6 is a code list diagram of an ID field.

FIG. 7 is a structural diagram of an option field.

FIG. 8 is a flowchart of a server-side processing program.

FIG. 9 is a flowchart of a terminal-side processing program.

[Explanation of symbols]

 Allowed number of CTs 3 Terminal 12 CPU (encoding unit, generating unit, distribution unit) 30 Image file (data file) 31 Data file (data file for transmission)

Claims (5)

[Claims] 1. A data distribution method for distributing a data file requested by a terminal to the terminal, the method comprising: encoding the data file in a predetermined format; and transmitting information for decoding the encoded data. A data distribution method, comprising: generating a data file for transmission using a header section including the encoded data and the encoded data; and distributing the data file to a requesting terminal. 2. The data distribution method according to claim 1, wherein said header section includes an allowable number of times of decoding. 3. A data distribution device for distributing a data file requested by a terminal to the terminal, an encoding unit for encoding the data file in a predetermined format, and an encoding unit for decoding the encoded data. A data distribution apparatus comprising: a header section including information; a generation unit configured to generate a data file for transmission using the encoded data; and a distribution unit configured to distribute the data file to a requesting terminal. 4. The data distribution apparatus according to claim 3, wherein said generating means includes an allowable number of times of decoding in said header portion. 5. A recording medium storing a program for realizing the encoding means, the generation means, and the distribution means according to claim 3.