JPH11250141A - Method for distributing real time contents - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a real time contents distributing method capable of preventing the generation of illegal duplication or distribution without any a trouble in real time reproduction and preventing valid user's convenience from being lost. SOLUTION: In the case of reproducing ciphered contents by a terminal 2, a decihering key acquiring means 5 acquires a corresponding deciphering key from a key center 1 through a computer network 3. A contents deciphering/ reproducing/deleting means 6 deciphers/reproduces/deletes data in the contents in each fixed volume by using the acquired deciphering key, and at the time of ending the decipher/reproduction/deletion of all data of the contents, a deciphered key deleting means 7 deletes the deciphered key.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distribution method suitable for selling digital contents such as music and moving images on a network.

[0002]

2. Description of the Related Art As a method for selling digital contents such as music and moving images that require real-time properties, contents data is directly delivered to a user terminal via a network such as the Internet, and is directly reproduced and provided. Although there is a method, the content data is not sufficiently transmitted due to a change in the bandwidth of the line or the like, and the reproduction of music, moving images, and the like may be interrupted. In addition, when the size of the content is large, a large amount of data continuously flows over the network over a long period of time, which imposes a heavy load on the network and bears a communication fee proportional to the content playback time. There was also the problem that it had to be done.

As a method for solving the above-mentioned problem, there is a method of compressing data, delivering the data to a user terminal via a network, temporarily storing the content, and then decompressing and reproducing the content on the terminal. However, there is another problem that the stored content can be illegally copied and distributed.

[0004] As a typical method for addressing this problem, a method of embedding information of a user or the like in a content with a digital watermark or the like, a method of encrypting the content, and a special software and specific key information for reproducing the content are required. There is a method using a mechanism.

[0005]

However, the former method has an effect of suppressing illegal duplication / distribution of content, but cannot completely prevent it. In the latter method, a valid user of the content is required. There is a problem that the convenience of the system is also impaired.

For example, a music data sales company encrypts content with an encryption key for each user and compresses the data.
This is delivered to the user's terminal via the network,
The user downloads a decryption key that is paired with the encryption key of each user at the time of user registration, and reproduces the decompressed data while decrypting the data with the key and a dedicated player (software).

[0007] This method can solve the problem that the reproduction is interrupted and the like, and can prevent illegal duplication / distribution of the contents. In other words, there is a problem that the convenience of the user is impaired, for example, it is impossible to perform the reproduction by the user.

In general, since the data amount becomes larger than the original data when the encryption processing is performed, the distribution via the network is accompanied by the problem of the load on the network and the long time download. The problem of communication charges remained.

[0009] An object of the present invention is not to hinder real-time reproduction of contents, and to prevent unauthorized duplication and reproduction.
It is an object of the present invention to provide a method for distributing real-time content which can prevent distribution and does not impair convenience of a legitimate user.

[0010] It is another object of the present invention to provide a method for real-time content that can use a medium other than a network such as the Internet for delivery of content, and can solve the problems of load on the network and communication charges associated with long-term download. To provide a delivery method.

[0011]

In order to solve the above-mentioned problems, the present invention provides a method for real-time reproduction of digital contents, such as music and moving images, requiring real-time performance on a user terminal connected to a network. In the content distribution method, the content encrypted with a predetermined encryption key is delivered to the user side, and when using the content, the user obtains a decryption key corresponding to the encryption key through a network, The content is decrypted and reproduced using the decryption key, and the decrypted content and the decryption key are deleted from the user's terminal.

According to the above configuration, the encrypted content already delivered to the user side can be decrypted and reproduced on the terminal of the user, so that the content data is sent as it is via the network. Thus, high-quality real-time reproduction can be performed without interruption of reproduction due to a change in the line band. Further, although the encrypted content remains on the user side, the decrypted content is deleted, so that illegal duplication / distribution of the content can be prevented. In addition, a legitimate user only needs to obtain a decryption key via a network, and can reproduce content on any terminal.

[0013] Further, there is no restriction on the distribution of the encrypted contents, and an inexpensive recording medium such as a CD-ROM can be used. Therefore, the load on the network when a computer network such as the Internet is used. And the problem of communication charges associated with long download times can be solved.

[0014] Decryption / reproduction of the encrypted content and deletion of the decrypted content are continuously performed in units of a certain amount of data in the content, and decryption / reproduction of all data of the content is completed. After that, if the decryption key is deleted, illegal duplication / distribution of the decrypted content can be more strongly prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of an embodiment of a method for delivering real-time contents according to the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of a system according to the present embodiment. In the figure, 1 is a key center, 2 is a plurality of terminals constituted by a personal computer, etc., 3 is a computer for arbitrarily connecting these. Network.
Here, digital contents that need to be sold, such as music and moving images, that require real-time properties, are encrypted with an appropriate encryption key for each content, and stored in a medium such as a CD-ROM and transmitted to the user side. It is assumed that the contents are delivered and ready to be decoded and reproduced on the terminal 2.

FIG. 2 shows a main part of the system, wherein the key center 1 comprises a decryption key providing means 4, and each terminal 2 comprises a decryption key obtaining means 5, a content decrypting / reproducing / deleting means. 6 and a decryption key deleting means 7. Each of these means is realized by a computer constituting the key center 1 and the terminal 2 and their programs.

The key providing means 4 provides a decryption key corresponding to an encryption key for each content to the terminal 2 via the computer network 3 in response to a request from the terminal 2.

The decryption key obtaining means 5 realizes encrypted communication with the key center 1 via the computer network 3 and obtains a decryption key from the key center 1. Here, message a
Contains information specifying which key of which key center is needed, and message b is a message containing a decryption key.

The content decryption / reproduction / deletion means 6 decrypts / reproduces the encrypted content using the decryption key acquired by the decryption key acquisition means 5 and further deletes the content.
At this time, the decryption / playback of the encrypted content and the deletion of the decrypted content are continuously performed in units of a certain amount of data in the content.

The decryption key deletion means 7 deletes the decryption key acquired by the decryption key acquisition means 5 after decryption / reproduction and deletion of all data of the corresponding content are completed.

In the above configuration, when the user instructs the terminal 2 to reproduce a certain (encrypted) content, the decryption key obtaining means 5 is activated, and the decryption key corresponding to the content is determined by which key center A message a specifying whether or not the key is sent to the computer network 3. Upon receiving the message a via the computer network 3, the key center 1 sends a message b containing the corresponding decryption key.
Will be returned.

The decryption key acquiring means 5 of the terminal 2 which has received the message b via the computer network 3 extracts the decryption key from the message b and sends it to the content decrypting / reproducing / deleting means 6.

The content decrypting / reproducing / deleting means 6 reads the first fixed amount of data from the encrypted content, performs decryption / reproduction using the decryption key, and deletes the decrypted data. Next, a certain amount of data subsequent to the read data is read, and the same processing is performed.
In the same manner, similarly, data in the encrypted content is read by a fixed amount, and decryption / reproduction and deletion are repeated.

When the decryption, reproduction and deletion of all data of the content are completed in this way, the decryption key deletion means 7 deletes the decryption key.

[0026]

As described above, according to the present invention,
In the sale of digital content that requires real-time properties, stable playback can be achieved without interruption of content playback. In addition, if the user is a valid user, the content can be reproduced on any terminal connected to the network, and illegal duplication / distribution of the content can be prevented while ensuring the convenience of the valid user.

Further, the delivery of the encrypted contents does not need to be performed via a network.
It can be delivered even when it is stored on inexpensive and large-capacity media such as OM.
Content can be sold without worrying about communication charges associated with long downloads.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing an example of an embodiment of a real-time content distribution method according to the present invention;

FIG. 2 is a configuration diagram of a main part in the system of FIG. 1;

[Explanation of symbols]

1: key center, 2: terminal, 3: computer network, 4: decryption key providing means, 5: decryption key acquisition means, 6: content decryption / reproduction / deletion means, 7: decryption key deletion means.

Claims (2)

[Claims] 1. A method of distributing real-time contents such as music and moving images which requires real-time properties on a user terminal connected to a network, wherein the digital contents are encrypted with a predetermined encryption key. Delivering the content to the user side, and when using the content, the user obtains a decryption key corresponding to the encryption key through a network, decrypts and reproduces the content using the decryption key, A method for delivering real-time content, wherein the decrypted content and the decryption key are deleted from a user terminal. 2. Decryption / playback of the encrypted content and deletion of the content after decryption are continuously performed in units of a fixed amount of data in the content, and decryption / playback of all data of the content is completed. 2. The method according to claim 1, wherein the decryption key is deleted after the execution.