JP3893256B2 - Network moving image distribution method and system, network moving image distribution program, and recording medium recording the program. - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and a system for distributing or receiving a moving image while ensuring the security of a moving image by encryption between computers via a network, and a terminal device used in the system.
[0002]
[Prior art]
Conventionally, all moving images are encrypted with one encryption key, the encrypted moving image is distributed, the decryption key is distributed later, and the receiving side performs decryption processing.
[0003]
[Problems to be solved by the invention]
The problem with the prior art is that the entire moving image is encrypted with a single key. When one key is broken, all moving images can be viewed, leading to free viewing and leakage of confidential information. Furthermore, since the entire moving image is encrypted with one key, the communication protocol on the delivery side and the reception side is simple, and some processing cannot be added interactively. For example, even if the advertisement time is put in the middle of a moving picture as in the case of a commercial television, there is only a means for creating and encrypting a moving picture including an advertisement.
[0004]
The present invention is for solving the problems of the above-described conventional technology, and improves security, reduces damage even if the key is broken, and improves interactivity between the distribution side and the reception side. It is an object of the present invention to provide a network moving image distribution method and system, and a terminal device used in the system.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, a network moving image distribution method according to the present invention divides a moving image digitized by MPEG along a time axis, and a part of the divided moving image units with different encryption keys. Encryption process for generating a moving image for distribution, an encrypted moving image distribution process for distributing only the encrypted portion of the moving image for distribution, and the divided moving image unit A key management process for managing the decryption key and the unencrypted portion of the moving image, and distributing the decryption key and the unencrypted portion of the moving image in response to a request for the decryption key from the receiving side receiving the distribution; In the encryption process, all of the B frame and all of the P frame are encrypted, and part or all of the I frame is not encrypted, and the rest of the I frame other than the unencrypted part is encrypted. With features To do.
[0007]
Alternatively, the network moving image distribution method described above is characterized in that, after the key management process, there is a charging information generation process for generating charging information based on the distribution of the decryption key.
[0013]
In order to solve the above problem, the network moving image distribution system according to the present invention divides a moving image digitized by MPEG along a time axis, and uses a different encryption key for each divided moving image unit. An encryption processing unit that encrypts a part and creates a moving image for distribution, an encrypted moving image distribution unit that distributes only an encrypted portion of the moving image for distribution, and the divided moving image Key management that manages the decryption key and the unencrypted portion of the moving image in units, and distributes the decryption key and the unencrypted portion of the moving image in response to a request for the decryption key from the receiving side that received the distribution The encryption processing unit encrypts all of the B frame and all of the P frame, does not encrypt part or all of the I frame, and encrypts the remaining I frames other than the unencrypted part. characterized in that the reduction And
[0014]
Alternatively, the above-described network moving image distribution system includes a charging information generation unit that generates charging information based on the distribution of the decryption key.
[0019]
Alternatively, since the process in the network moving image distribution method is executed by a computer, a network moving image distribution program is used.
[0020]
Alternatively, a network moving image distribution program for executing the process in the network moving image distribution method by a computer is recorded on a recording medium readable by the computer.
[0021]
In the present invention, in order to improve security, which is one of the problems, the distribution side divides the moving image along the time axis, encrypts and distributes the divided moving image units with different encryption keys, When the receiving side receives the encrypted moving image, the receiving side requests the decoding source for the divided moving image unit, the distributing side distributes the decoding key, and the receiving side encrypts from the decoding key. The decoded moving image is decoded and output to a computer device. In this way, the moving image is divided, encrypted with different keys, and distributed to improve security. That is, even if one key is broken, the damage can be reduced by reducing the range that can be viewed with the broken key.
[0022]
In the present invention, in order to further improve security, the distribution side encrypts only a part of the divided moving image units, distributes only the encrypted part, and the reception side performs encryption. When the moving image of only the part that has been received is received, a decryption key is requested from the distribution source for each divided moving image unit, and the distribution side manages the decryption key and the unencrypted part of the moving image. The decryption key and the unencrypted part are distributed in response to the request, and the receiving side decrypts the encrypted moving image from the decryption key, and adds the unencrypted moving image to Restore and output to computer equipment. In this way, a part is encrypted and distributed, and a part that is not encrypted is sent later, so that even if the key is broken, it is not possible to view without a part that is sent later, thus further improving security. Further improve.
[0023]
Furthermore, in the present invention, the distribution side manages the distribution conditions of the decryption key, distributes the information described in the distribution conditions before the distribution of the decryption key so that the processing is added interactively, and the reception side , Receiving information serving as a distribution condition and outputting it to a computer device. In this way, by distributing the distribution condition information before distributing the encryption key in response to a request from the receiving side, it is possible to insert an advertisement in the middle of the video and improve the interactivity between the distributing side and the receiving side Let
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0025]
FIG. 1 is a block configuration diagram of a distribution side (for example, a center device) according to an embodiment of the present invention, and FIG. 2 is a block configuration diagram of a reception side (terminal device) according to an embodiment of the present invention. Shows a processing flow of a moving image distribution method according to an embodiment of the present invention. 1 and 3 and FIGS. 2 and 3 are given the same numbers to clarify the relationship between functional blocks and processes. In addition, in FIG. 1 to FIG. 3, functional blocks and processes indicated by dotted lines are not essential.
[0026]
First, the distribution side in FIG. 1 will be described. 11 is an encryption processing unit that encrypts the digital moving image 31, and 12 is an encryption moving image distribution unit that distributes the moving image 32 encrypted by the encryption processing unit 11. , 13 is a key distribution pre-processing unit that distributes distribution condition information 37 such as an advertisement before distribution of the decryption key 34, and 14 is a portion of the moving image that is not encrypted with the decryption key 34 in units of divided moving images. The key management unit 15 that manages the image 33 and distributes the decryption key 34 and the unencrypted moving image 33 in response to a request for the decryption key from the reception side, 15 is triggered by the distribution of the decryption key 34 There is a billing information creation unit that creates billing information 38. In addition, there is a communication processing unit 16 with a network.
[0027]
Next, the receiving side in FIG. 2 will be described. 21 is an encrypted moving image receiving unit that receives and stores an encrypted moving image 32, and 22 is a decryption key of the received encrypted moving image 32. A key requesting unit 23 for requesting, a key receiving preprocessing unit 24 for receiving and outputting information distributed as a condition for receiving the decryption key before receiving the decryption key, and 24 for receiving the decryption key and the encryption key The moving image restoration unit 25 that receives the moving image 33 of the unconverted portion and restores the original digital moving image 31, 25 is a moving image output unit that outputs the restored digital moving image 31, There is a communication processing unit 26 with the network.
[0028]
The processing in this embodiment will be described in order of time with reference to FIG. Note that the present invention divides a digital moving image along the time axis and performs encryption using different encryption keys in divided units, and the flow of FIG. 3 shows one divided moving image unit. Shows the process. By repeating the flow of FIG. 3 for the number of divided moving images, the entire original moving image is processed.
[0029]
(Step 11) On the distribution side, the digital moving image is partially or entirely encrypted and stored.
[0030]
(Step 12) On the distribution side, only the encrypted part is distributed.
[0031]
(Step 21) On the receiving side, the moving image of only the encrypted part is received and stored.
[0032]
(Step 22) On the receiving side, a decryption key for the encrypted moving image is requested to the distribution source.
[0033]
(Step 13) Upon receiving the request for the decryption key, the distribution side refers to the distribution condition table 36 of FIG. 1 describing the distribution condition of the decryption key. To deliver.
[0034]
An example of the distribution condition table is shown in FIG. The column is a time-series time of the divided moving image and a file name serving as a distribution condition. In addition, it is assumed that the rows are arranged from the top in time series. In this example, File1 is distributed when the moving image is the first (time t0), and File2 is distributed when the moving image is at time t4.
[0035]
(Step 23) Upon receiving information serving as a distribution condition on the receiving side, the information is output to an output device. Specifically, when an advertisement moving image is received, it is reproduced on a display. If an HTML file is received, it is displayed on the Web browser. When the URL is received, a process of accessing from a Web browser is performed. The content is not limited to advertisements, but may be questionnaires or quizzes.
[0036]
As can be seen from the distribution condition table in FIG. 4, information serving as a distribution condition may not be received.
[0037]
(Step 14) The distribution side distributes the requested decryption key. In addition, if there is a portion of the moving image that is not encrypted, the portion of the moving image that is not encrypted is distributed. The decryption key and the unencrypted portion of the moving image are managed by the decryption key management table 35 in FIG. 1, and the unencrypted moving image is encrypted with the decryption key 34 based on the decryption key management table 35. 33 is distributed.
[0038]
An example of the decryption key management table is shown in FIG. The columns are the time-series time of the divided moving image, the decryption key, the pointer and size to the memory storing the unencrypted moving image portion, and the reproduction time of the divided moving image. In addition, it is assumed that the rows are arranged from the top in time series. In this example, key0 is distributed at the time of the first moving image (time t0), and the unencrypted portion stored in the memory is determined from Pointer0 and size0 and distributed.
[0039]
If all are encrypted, there is no unencrypted moving image, and there is no need to manage unencrypted moving images in the decryption key management table.
[0040]
(Step 24) On the receiving side, the decryption key and the unencrypted moving image portion are received, and the encrypted moving image portion already received in Step 21 is decrypted with the decryption key. The portion of the unencrypted moving image received in step 1 is added to restore the original moving image.
[0041]
Note that if all are encrypted, there is no unencrypted moving image, and the original moving image is restored when decrypted with the decryption key.
[0042]
(Step 25) On the receiving side, the restored moving image is output to the output device. In general, display on the display. It may be stored in a file.
[0043]
(Step 15) On the distribution side, if charging is necessary, charging information is created in response to the distribution of the decryption key in step 14.
[0044]
An example of billing information is shown in FIG. The column indicates the date and time when the decryption key was distributed, the user ID used, the name of the distributed video file (the file name of the entire video before division), the distributed decryption key, and the playback time of the video restored by the decryption key It is. By managing moving image files, it becomes possible to specify the contents of moving images, and to record time-based charges by recording playback time.
[0045]
In the first line of the example in FIG. 6, the user “User1” receives the decryption key “Key0” on April 23, 2001 for viewing the movie “Movie1”, and can view a moving image for 2 seconds. It shows that it became.
[0046]
The overall processing flow has been described above. Here is a little supplement.
[0047]
Either of the time order of the processing of step 25 and step 15 may be first. This is because the distribution side and the reception side are separate computer devices, and the processing proceeds separately.
[0048]
Similarly, the distribution side and the reception side are separate computer devices, and considering that the processing proceeds separately, there is no guarantee that step 14 ends and step 14 is processed. In order to guarantee this order, in step 23, the receiving side receives information serving as distribution conditions, outputs the information to an output device, sends a viewing completion signal to the distribution side with confirmation of user viewing, The distribution side may use a method of proceeding with the process of step 14 upon receipt of a viewing completion signal. The confirmation of viewing by the user here means that the reproduction has been completed to the end if it is an advertisement video, or that the questionnaire has been answered if it is a questionnaire. Of course, there is also a method of proceeding the processing by regarding the output to the computer device of information serving as a distribution condition without regard to the user's viewing confirmation, and regarding the confirmation as viewing confirmation.
[0049]
In the description so far, processing in units of one moving image divided along the time axis has been shown. Here, the distribution of the entire moving image will be described with reference to FIG. In FIG. 7, the shaded area indicates an encrypted part.
[0050]
The original moving image is divided along the time axis, and is divided into t0 to t3 in FIG. Each of the divided moving images is partially or entirely encrypted with different encryption keys, and becomes an encrypted part E0 and an unencrypted part S0. Regarding the divided moving image t0, on the line,
1. Encrypted part (E0)
2. Decryption key (key 0)
3. Unencrypted part (S0)
Are delivered in this order. If everything is encrypted, the third unencrypted part (S0) is not distributed. Further, if there is a description in the distribution condition table, information ( File1) serving as a distribution condition is distributed between the first and second. Following the divided moving image t0, the processes of t1, t2, and t3 are repeated.
[0051]
Here, the encryption of a part of a moving image will be described in more detail.
[0052]
As shown in (1) of FIG. 8, in normal MPEG, the I and P pictures are encoded in the same order as the original image, and after processing the I and P pictures first, the B picture inserted between them is encoded later. Turn into. Here, as shown in (2) of FIG. 8, the I frame is extracted, and the remaining B and P frames are encrypted and distributed first. The I frame is not encrypted and is distributed later along with the decryption key.
[0053]
Further, as shown in (2) of FIG. 9, all of the B and P frames and half of the I frame are encrypted and distributed first, and the other half of the I frame is not encrypted and is distributed later together with the decryption key. There is also a way to do it.
[0054]
Now, finally, nothing has been described about the encryption method, but a known encryption method can be used. However, it is desirable that encryption strength is moderately strong and encryption processing can be performed at high speed. PERRM (Reference: “Examination of E-mail Transfer Service Method”, IEICE, Office System Research Group, Vol.97, No.280, pp37-42, (1997.9.26)).
[0055]
Note that some or all of the functions of each unit on the distribution side (center device or the like) shown in FIG. 1 and the reception side (terminal device) shown in FIG. 2 are configured by a computer program, and the program is used by the computer. The present invention can be realized by executing the processing, or the processing process in the distribution-side center device and the receiving-side terminal device shown in FIG. 3 is configured by a computer program, and the program is executed by the computer. Needless to say, a program for realizing the function of the computer or a program for causing the computer to execute the process is recorded on a recording medium readable by the computer, such as an FD (floppy disk). (Registered trademark)), MO, ROM, memory card, CD, DV , And recorded in a removable disk, or stored, it is possible or distribute. It is also possible to provide the above program through a network such as the Internet or electronic mail. Needless to say, this program is created separately for the distribution side (center device or the like) and the reception side (terminal device).
[0056]
【The invention's effect】
According to the present invention, since a moving image is divided and encrypted and distributed with different keys, security is improved. Even if one key is broken, the range that can be viewed with the broken key is small and the damage is reduced.
[0057]
In addition, since a part is encrypted and delivered, and an unencrypted part is sent later , even if the key is broken, it cannot be viewed unless there is a part sent later, and security is further enhanced. improves.
[0058]
Furthermore, after distributing the video, encrypting it with a different key and distributing it, if the distribution conditions are distributed before distributing the encryption key, an advertisement can be inserted in the middle of the video. Improves.
[Brief description of the drawings]
FIG. 1 is a block diagram of a transmitting side of a network moving image distribution system according to an embodiment of the present invention. FIG. 2 is a block diagram of a receiving side of a network moving image distribution system according to an embodiment of the present invention. FIG. 4 is a flowchart showing an example of a delivery condition table in an embodiment of the present invention. FIG. 5 is a decryption key in an embodiment of the present invention. FIG. 6 is a view showing an example of a management table. FIG. 6 is a view showing an example of billing information in an embodiment of the present invention. FIG. 7 is an image view of distribution of all moving images in an embodiment of the present invention. FIGS. 9A and 9B are diagrams showing examples of partial ciphers in an embodiment of the present invention. FIGS. 9A and 9B show another example of partial ciphers in an embodiment of the present invention. Figure [description of symbols]
DESCRIPTION OF SYMBOLS 11 ... Encryption processing part 12 ... Encryption moving image delivery part 13 ... Key distribution pre-processing part 14 ... Key management part 15 ... Billing information creation part 16 ... Communication processing part 21 ... Encrypted moving picture receiving part 22 ... Key request part 23 ... Key Pre-reception processing unit 24 ... moving image restoration unit 25 ... moving image output unit 26 ... communication processing unit

Claims (6)

A process of dividing a moving picture digitized by MPEG along a time axis, encrypting a part of the divided moving picture unit with a different encryption key, and creating a moving picture for distribution;
An encrypted moving image distribution process for distributing only the encrypted portion of the moving image for distribution;
The divided moving image unit manages the moving image of the decryption key and the unencrypted portion, and the decryption key and the unencrypted portion of the moving image according to the request for the decryption key from the receiving side receiving the distribution The key management process to deliver the image,
In the encryption process, all of the B frame and all of the P frame are encrypted, and part or all of the I frame is not encrypted, and the remaining I frames other than the unencrypted part are encrypted. Network video distribution method. After the key management process,
A billing information creation process for creating billing information based on the distribution of the decryption key
The network moving image distribution method according to claim 1, wherein: An encryption processing unit that divides a moving image digitized in MPEG along a time axis, encrypts a part of the divided moving image unit with a different encryption key, and creates a moving image for distribution;
  An encrypted moving image distribution unit that distributes only the encrypted portion of the moving image for distribution;
  The divided moving image unit manages the moving image of the decryption key and the unencrypted portion, and the decryption key and the unencrypted portion of the moving image according to the request for the decryption key from the receiving side receiving the distribution A key management unit that distributes images,
  The encryption processing unit encrypts all of the B frame and all of the P frame, does not encrypt all or part of the I frame, and encrypts the remaining I frames other than the unencrypted part.
A network moving image distribution system characterized by the above. It has a billing information creation unit that creates billing information based on the distribution of the decryption key
  The network moving image distribution system according to claim 3. The process in the network moving image delivery method according to claim 1 or 2 is a program for executing on a computer.
  A network moving image distribution program characterized by the above. A network moving image distribution program for executing the process in the network moving image distribution method according to claim 1 or 2 on a computer is recorded on a computer-readable recording medium.
  A recording medium on which a network moving image distribution program is recorded.

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