JPH07336317A - Video on demand system - Google Patents

Abstract

PURPOSE:To provide a video on demand system for which the danger of getting a deciphering key stolen by a third person at the time of ciphering video data and distributing them to a video terminal is less, the time required for the deciphering processing of the video terminal is short and a hardware amount is not increased. CONSTITUTION:The video data to be distributed to the video terminal are compression-processed in a video server 1, then ciphered by using a ciphering key and transmitted. Then, the video data distributed from the video server 1 are deciphered by using the deciphering key stored in an IC card 8 in the demand controller 6 of the video terminal, then expansion-processed and displayed at a television monitor 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video-on-demand system, and more particularly to a video-on-demand system in which video data is encrypted from a video server and delivered to a video terminal.
Regarding demand system.

[0002]

2. Description of the Related Art As a system in which a user can watch a program such as a movie or a concert at a general home,
Video on demand is being considered. Video on demand is, for example, "Nikkei Communication" 1
As described on pages 82 to 83 of the April 4, 994 issue, from a video terminal provided in a general home,
This is a system for accessing a database called a video server, which stores data of a large number of programs provided in a center, and distributing a program desired by a user from the video server. As a specific procedure, when the user who owns the video terminal makes a distribution request of a desired program to the video server, the video data of the program is distributed from the video server to the video terminal.

[0003]

Since the video-on-demand system is generally premised on the distribution of programs for a fee, it is used as a measure against unauthorized use by non-subscribers or those who have not paid the fee. , It is necessary to encrypt and distribute the video data from the video server. The encryption is performed using an encryption key, and the video terminal side decrypts (decrypts) using a decryption key corresponding to the encryption key.

Therefore, it is necessary for the video terminal side to know the decryption key in advance, but the issue is how to deliver the decryption key to the video terminal. In the method of delivering the decryption key via the line for the video data, there is a risk that the decryption key will be stolen by a third party. If the decryption key itself is also encrypted and transmitted, such a risk is reduced, but for that purpose, it is necessary to decrypt the encrypted decryption key with another decryption key on the video terminal side. As a result, not only the decoding process takes time, but also the amount of hardware and the cost for decoding increase. Since the video terminal of the video-on-demand system is installed in a general household, it is required to be small and inexpensive, but the method of encrypting the decryption key and transmitting it requires such a requirement. This is contrary to, and is not preferable in practice.

According to the present invention, when the video data is encrypted and distributed to the video terminal, the risk that the decryption key is stolen by a third party is small, and the time required for the decryption processing of the video terminal is short. , An object is to provide a video-on-demand system that does not increase the amount of hardware.

[0006]

In order to solve the above-mentioned problems, the present invention responds to a distribution request from a user who uses a video terminal, from a video server accumulating video data of a plurality of programs, the user In a video-on-demand system that distributes video data of a desired program to the video terminal, the video server is provided with an encryption unit that encrypts the video data to be distributed to the video terminal using a predetermined encryption key, It is characterized in that the video terminal is provided with a decryption means for decrypting the video data distributed from the video server by using a decryption key stored in an IC card loaded in the video terminal.

Further, according to the present invention, the video server is further provided with a compression means for compressing the video data to be delivered to the video terminal, and the compressed video data is encrypted by using a predetermined encryption key. Then, the video terminal is provided with a decompressing means for decompressing the video data distributed from the video server, and the video data decompressed by the decompressing means is decrypted using the decryption key stored in the IC card loaded in the video terminal. It is characterized in that it is adapted to.

[0008]

As described above, the video on demand of the present invention is
In the system, since the IC card loaded in the video terminal stores the decryption key for decrypting the encrypted video data distributed from the video server, the decryption is performed via the line for the video data. Unlike the method of transmitting the key, the possibility that the decryption key is stolen is significantly reduced. Further, since it is not necessary to encrypt the decryption key itself, the processing time required for decryption in the video terminal is shortened and the hardware scale is reduced.

Furthermore, if the video server compresses the video data to reduce the amount of information, then encrypts it, and then decrypts it at the video terminal and then expands it, the line can be occupied until the end of viewing the program. Since it does not exist, effective use of expensive lines and communication use can be saved,
The amount of processing required for encryption and decryption is reduced, and the hardware scale is further reduced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a video-on
It is a block diagram showing a schematic structure of a demand system. In the figure, a video server 1 is arranged at the center of a video-on-demand system and stores data of many programs such as movies in a large-capacity storage medium represented by an optical disc (video disc). This video server 1 is connected to a subscriber terminal device 3 directly and via an ISDN line 2. The subscriber terminal device 3 is connected to one end of the optical fiber 4.

On the other hand, on the subscriber side of the video-on-demand system, a demand control device 6 and a television monitor 7 are provided as video terminals. Demand control device 6
Has a function of mainly sending a program distribution request designated by the user to the video server 1 and supplying video data of the program distributed from the video server 1 to the television monitor 7 for display. It is connected to the other end side of the optical fiber 4 via. Further, the demand control device 6 has an IC
The card 8 can be loaded.

FIG. 2 is a diagram showing the internal structure of the demand control device 6 and the IC card 8. As shown in the figure,
The demand control device 6 includes an ISDN interface unit 11,
Central processing unit 12, read / write device 13, contact unit 1
4, a ROM 15 storing a program as a processing procedure of the central processing unit 12, storage units 16 and 17, a selection key 18, and a display unit 19. ISDN interface unit 1
An interface 1 is interposed between the network control device 5 and the central processing unit 12 and the read / write device 13, and is used when information is exchanged between the video server 1 and the video terminal via the ISDN line 2. Control The central processing unit 12
It is connected to the network terminating device 5, the television monitor 7, the ISDN interface unit 11 and the reading / writing device 13 and performs various demand controls described later. The reading / writing device 13 reads the data recorded in the IC card 8 and I
Data is written to the C card 8. The contact portion 14 is
When the IC card 8 is loaded into the demand control device 6, the IC card 8 is electrically connected to a contact portion, which will be described later, of the IC card 8 in order to enable signal exchange between the two.

First storage unit 16 and second storage unit 17
Is for temporarily storing the received video data for decoding processing and decompression processing. Further, the selection key 18 is a key for selecting a program, and the display section 19 is for displaying a program list and the like.

On the other hand, the IC card 8 includes a storage unit 21 including an IC memory, a central processing unit (CPU) 22, and a central processing unit 2.
ROM 23 storing the program as the processing procedure of No. 2
And a contact portion 24. The storage unit 21 stores a user ID that is assigned to a user who uses the video terminal and that is registered in advance and that identifies the user, and a decryption key for decrypting the encrypted video data. The central processing unit 22 performs the processing described later according to the demand control based on the program stored in the ROM 23. Contact part 24
Is electrically connected to the contact portion 14 of the demand control device 6 in order to enable the exchange of signals between the demand control device 6 and the IC card 8 when the IC card 8 is loaded in the demand control device 6. Connected.

FIG. 3 is a diagram showing an internal configuration of the video server 1. The video server 1 has a central processing unit 31 and an R storing a program as a processing procedure of the central processing unit 31.
OM32, a video software selection unit 33 for selecting and reading out video data (video software) of a program designated by program selection information from the video terminal from the above-mentioned large-capacity storage medium such as an optical disc, read video data , A compression unit 34 for compressing the compressed video data under the control of the central processing unit 31 based on the encryption key 35, and a video output unit 37 for outputting the compressed / encrypted video data. Have.

FIG. 4 is a time chart for explaining a video data processing operation in the video server 1 and the demand control device 6. 4A to 4C show processing operations in the video server 1. FIG. 4A shows video data output from the video software selection unit 33.
The frame is divided into a plurality of blocks B1, B2, .... The video data is compressed by the compression unit 34 in block units as shown in FIG. As a compression technique in the compression unit 34, for example, MP that combines motion compensation predictive coding with DCT (discrete cosine transform) and variable length coding
The EG method can be used. By this compression, the information amount of the video data is highly efficiently reduced, and the lengths (time axis) of the blocks F1, F2, ... Are also compressed as shown in FIG. The video data compressed in this way is encrypted in block units in the encryption unit 36 based on the encryption key 35 as shown in FIG. That is, the blocks F1, F2, ... Of FIG.
Each of S2, ... Is encrypted. in this case,
The encryption key 35 may be constant, but it is more preferable to change it for each block. In addition, every fixed time (for example, every 1 minute)
Alternatively, the decryption key may be changed.

On the other hand, in the demand control device 6, FIG.
Of the image data is received, and first, by using the decryption key stored in the IC card 8, the central processing unit 12 in the demand control device 6 performs decryption, which is the reverse process of the encryption unit 36. The same video data as in FIG. 4B is obtained in 4D. The decryption process may be performed by the central processing unit 22 in the IC card 8. Further, the decoded video data is subjected to a decompression (also called decompression) process which is the reverse process of the compression unit 34, and the original video data is reproduced as shown in FIG. 4 (d).

Next, the operation of the video-on-demand system of this embodiment will be described with reference to the flow chart shown in FIG. In the following description, when the information is transmitted from the video server 1 to the demand control device 6 on the video terminal side, the information output from the video server 1 is sent to the subscriber terminal device 3 directly or via an ISDN line. Then, it is transmitted from the subscriber terminal device 3 to the demand control device 6 via the optical fiber 4 and the network terminating device 5. The demand control device 6 takes in the information sent from the video server 1 from the network terminating device 5 to the central processing unit 12 directly or via the ISDN interface unit 11.

On the other hand, in the communication of information from the demand control device 6 to the video server 1, necessary information is sent from the control unit 12 to the network terminating device 5 directly or via the ISDN interface unit 11, and the network terminating device is further sent. 5 is sent to the video server 1 via the optical fiber 4 and the subscriber terminal device 3. The video server 1 takes in the information sent from the demand control device 6 directly from the subscriber terminal device 3 or via the ISDN line 2.

When the video terminal receives the distribution of the program from the video server 1, the user of the video terminal first loads the IC card 8 into the demand control device 6 (S1). By loading the IC card 8, the user ID stored in the storage unit 21 is sent to the video server 1 (S2). That is, when the IC card 8 is loaded into the demand control device 6,
The central processing unit 22 reads the user ID from the storage unit 21. The read user ID is read by the reading / writing device 13 via the contact portion 24 and the contact portion 14 and sent from the central processing unit 12 to the video server 1.

The video server 1 receives the user ID sent from the video terminal side, and when it confirms that the user ID is already registered, sends the authentication confirmation information to the demand control device 6 on the video terminal side. When this authentication confirmation information is received by the demand control device 6 (S3), the demand control device 6 becomes ready to accept the selection of the program by the user. Here, when the user using the video terminal selects a desired program from the program list displayed on the display unit 19 by the selection key 18 (S4), the program selection information indicating the selected program is displayed in the central processing unit 12. From video server 1
Sent to. In this way, by transmitting the user ID and the program selection information from the demand control device 6 to the video server 1, the user issues a program distribution request to the video server 1.

When the video server 1 receives the program selection information, the video software of the program designated by the program selection information is selected by the video software selection unit 33 and read out as shown in FIG. ), The compression unit 34 compresses in block units (S5). Next, the compressed video data is sent to the encryption unit 36, and encrypted using the encryption key 35 as shown in FIG. 4C (S6). Then, the compressed and encrypted video data is output from the video output unit 37 and transmitted (S7).

On the other hand, the demand control device 6 receives the video data transmitted from the video server 1 (S
8), the data is stored in one of the first and second storage units 16 and 17, and the central processing unit 12 decodes it in block units as shown in FIG. 4D (S9). That is, the video data of the first block is stored in the first storage unit 16,
The video data of the next block is decoded while being read from the video data 6, and the video data of the next block is stored in the second storage unit 17. The video data of the next block is read and decoded while being stored for each block. The data is alternately stored in the units 16 and 17 and decrypted. In this case, the storage unit 2 of the IC card 8
1, the decryption key is read, read from the central processing unit 22 in the IC card 8 via the contact unit 24 and the contact unit 14 by the read / write device 13 in the demand control device 6, and sent to the central processing unit 12. . In the central processing unit 12, the decryption key thus sent from the IC card 8 is used for decryption.

The video data thus decoded by the central processing unit 12 is further processed by the central processing unit 12 as shown in FIG.
, The first and second storage units 16,
It is output to and displayed on the television monitor 7 via the storage unit that has not been subjected to the decoding process out of 17 (S10).
Then, when the program being distributed ends (S11), the user of the video terminal removes the IC card 8 from the demand control device 6, and the series of processing ends (S12).

[0025]

As described above, according to the present invention, since the IC card loaded in the video terminal stores the decryption key for decrypting the encrypted video data from the video server, The possibility of the decryption key being stolen is significantly reduced, and since the decryption key itself does not need to be encrypted, the processing time required for decryption at the video terminal is shortened and the hardware scale is reduced. There is an advantage.

Further, if the video data is compressed in the video server to reduce the amount of information and then encrypted, and the video terminal is decrypted and then expanded, the line can be occupied until the end of viewing the program. Since it does not exist, effective use of expensive lines and communication use can be saved,
The amount of processing required for encryption and decryption is reduced, and the hardware scale is further reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a video-on-demand system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing internal configurations of a demand control device and an IC card in FIG.

FIG. 3 is a block diagram showing the internal configuration of the video server in FIG.

FIG. 4 is a time chart for explaining a video data processing operation in the embodiment.

FIG. 5 is a flowchart for explaining an operation procedure of the embodiment.

[Explanation of symbols]

1 ... Video server 2 ... ISDN line 3 ... Subscriber terminal device 4 ... Optical fiber 5 ... Network terminating device 6 ... Demand control device 7 ... TV monitor 8 ... IC card 11 ... ISDN interface unit 12 ... Central processing unit 13 ... Read / Writing device 14 ... contact part 15 ... ROM 16,17 ... storage part 18 ... selection key 19 ... display part 21 ... storage part 22 ... central processing part 23 ... ROM 24 ... contact part 31 ... central processing part 32 ... ROM 33 ... Video software selection unit 34 ... Compression unit 35 ... Encryption key 36 ... Encryption unit 37 ... Video output unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04N 5/76 B

Claims (2)

[Claims] 1. A video which, in response to a distribution request from a user using a video terminal, distributes video data of a program desired by the user to the video terminal from a video server which stores video data of a plurality of programs. In the on-demand system, the video server has an encryption unit that encrypts video data to be delivered to the video terminal using a predetermined encryption key, and the video terminal is delivered from the video server. A video-on-demand system, characterized in that it has a decryption means for decrypting the obtained video data using a decryption key stored in an IC card loaded in the video terminal. 2. A video which delivers video data of a program desired by the user to the video terminal from a video server which stores video data of a plurality of programs in response to a delivery request from a user who uses the video terminal. In the on-demand system, the video server compresses video data to be distributed to the video terminal, and encrypts the video data compressed by the compression means with a predetermined encryption key. The video terminal stores the video data distributed from the video server in an IC card loaded in the video terminal, and the video data expanded by the expansion means. A video-on-demand system, comprising: a decryption means for decrypting using a decryption key.