JP2006319417A - Information processing method and apparatus, computer program, and computer readable storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique efficiently executing multi-stage access control in a way of controlling accesses to a plurality of frame groups in access control applied to a moving picture. <P>SOLUTION: An importance acquisition section 42 acquires the importance for every frame configuring moving picture data, an encryption key setting section 43 sets an encryption key to each of the frames depending on the acquired importance, and an encryption section 44 uses the encryption key to apply encryption processing to the moving picture data by each frame. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to image data encryption and encryption / decryption techniques.

  Conventionally, image data encryption and scrambling have been performed for the purpose of controlling access to image data and the like. This is a technique in which image data is previously encrypted using an encryption key so that only a person having a decryption key corresponding to the encryption key can correctly reproduce the image data.

In particular, as an encryption technique for moving image data, as disclosed in Patent Document 1, it is possible to control access to the encrypted frame group by encrypting a predetermined frame group.
Japanese Patent Laid-Open No. 7-184188

  However, according to the prior art, one step of controlling whether or not to permit access to a single frame group (corresponding to the decryption key) depending on whether or not the decryption key is distributed. Although access control was possible, multi-stage access control for controlling access to a plurality of frame groups was difficult.

  Furthermore, there is no disclosure of a technique for automatically setting a frame group to be subjected to access control. In particular, encryption is performed when access control is performed on moving image data for a long time (including many frames). This is not efficient because it is determined manually for each frame.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a technique capable of efficiently executing access control for a plurality of frame groups.

  In order to solve the above-described problem, the present invention provides an importance level acquisition step for acquiring an importance level for each frame constituting image data encoded for each frame, and encryption for each frame according to the acquired importance level. An encryption key setting step for setting a key, and an encryption step for performing encryption processing on image data for each frame using the encryption key.

  According to the present invention, it is possible to control access to a moving image according to the importance for each frame.

<Description of overall configuration>
First, an example of a system outline in the present embodiment is shown in FIG. In the figure, an apparatus 11 is an image encryption apparatus that performs an encryption process on image data captured using a digital video camera or the like using a predetermined key. The device 12 is an image delivery server that delivers image data stored in the image DB 13 in response to a predetermined image data acquisition request. The device 14 is a key server that responds to a predetermined key data acquisition request and distributes key information stored in the key DB 15 and necessary for decrypting the encrypted image data. The device 16 is a billing server that executes a predetermined billing process. The device 17 is an image reproduction device that receives image data, decrypts the encryption of the received data, and reproduces the image data. The devices 11 to 17 are connected by a network such as the Internet 18 and can exchange various data with each other. The devices 11 to 17 may be general-purpose devices such as ordinary personal computers. The process flow will be briefly described as follows.

  The apparatus 11 performs compression encoding processing of desired image data and encryption processing using predetermined key data, and transmits the compression encoded and encrypted image data to the image distribution server 12. At the same time, the key data used for the encryption process is transmitted to the key server 14. In the key server 14, it is registered in the key DB 15 together with information (for example, an image ID) for specifying related image data.

  The image viewer uses the image reproduction device 17 to request the image distribution server 12 for desired image data and receives the image data. However, since the desired image data is encrypted, the key server 14 is requested for key information for decrypting it. At that time, for example, the key server 14 may distribute the key data only when it is confirmed by the charging server 16 that the predetermined charging process has been completed. In this way, the key data is transmitted from the key server 14 to the image viewer 17, and the encryption applied to the image data is decrypted by the image reproducing device 17 using the key data to reproduce the image data.

  In the present embodiment, it is assumed that the image data to be encrypted is moving image data that is compression-coded independently for each frame. In particular, in order to simplify the description, as an independent compression encoding method for each frame, it is assumed that the data is compression encoded data called JPEG 2000 standardized by ISO. It will be apparent from the following description that various compression encoding schemes such as JPEG can be applied without being limited to JPEG 2000.

  Before explaining details of the compression process and the encryption process in the apparatus 11, an example of an operation screen (window) of the encryption process in the embodiment will be described with reference to FIG.

  In FIG. 2, 21 is the window. In the upper part of the window 21, there are a column 22 for designating an input file including image data to be encrypted, and a column 23 for designating an output file including image data to be encrypted. The columns 22 and 23 may be specified by directly inputting a file name using a keyboard 315 shown in FIG. 3 to be described later, or a file browser is displayed by clicking a button provided at the right end of each column. You may make it select in it. The image data included in the file designated by the column 22 is displayed on the frame viewer 24. The frame viewer 24 displays moving image data or thumbnails thereof for each frame. Further, the importance level acquisition portion 25 is a user interface that sets the importance level of each frame corresponding to each frame of the frame viewer 24. As the importance setting means, the “manual setting” button 26 provided at the lower end of 25 may be used to directly specify the importance using a keyboard 315 or a mouse 314 shown in FIG. Alternatively, it may be set automatically by using an “automatic setting” button 27 provided at the lower end of 25. The “key selection” button 29 is an interface for selecting key data used for encrypting moving image data. The key data selection screen is displayed by clicking the “key selection” button 29, and the key data to be used for the encryption processing is selected by designating desired key data in the key data selection screen. If the user does not select key data using the “key selection” button 29, the program may automatically generate key data and use the generated key data for the encryption process. Each frame is actually encrypted corresponding to the importance set manually or automatically. In the present embodiment, the degree of reproduction of moving image data changes depending on the importance setting here. (This will be described later in detail.) Therefore, the display unit 28 can reproduce how the moving image data is actually reproduced by selecting the reproduction button 210 according to the set importance degree. Is possible. Note that when the reproduction is stopped, the stop button 211 is selected. After the desired importance is set in this way, the encryption process is actually executed by pressing the button 212, and the encrypted image data is recorded in the file designated in the field 23. The button 213 is selected when canceling the above processing.

  It should be noted that the window shown in FIG. 2 shows an embodiment applicable to the present invention, and it is obvious that the present invention is not limited to this.

  Next, a host computer applicable to this embodiment will be described with reference to FIG. FIG. 3 is a diagram illustrating a basic configuration of a host computer that functions as an image processing apparatus according to the present embodiment and a relationship with peripheral devices thereof. In the figure, a host computer 31 is a commonly used personal computer, for example, and can input and edit / store image data input from a video camera 316 via an I / F unit 317. . Further, the image data obtained here can be distributed via the Internet or the like using the NIC 310 or the modem 312. In addition, various instructions from the user are performed by input from the mouse 314 and the keyboard 315. Inside the host computer 31, blocks to be described later are connected by a bus 318, and various data can be transferred.

  In the figure, reference numeral 32 denotes a monitor capable of displaying various information from the host computer 31.

  Reference numeral 33 denotes a CPU that can control the operation of each unit in the host computer 31 or execute a program loaded in the RAM 35. Reference numeral 34 denotes a ROM that stores a BIOS and a boot program. Reference numeral 35 denotes a RAM for temporarily storing a program and image data to be processed for processing by the CPU 33, and a program for the OS and the CPU 33 to perform various processes described later is loaded therein. Become.

  A hard disk (HD) 36 is used for storing an OS and a program transferred to a RAM or the like, or for storing or reading image data while the apparatus is operating. Reference numeral 37 denotes a CD-ROM drive capable of reading or writing data stored in a CD-ROM (CD-R) which is one of external storage media.

  Reference numeral 38 denotes an FD drive that can read from an FD (floppy (registered trademark) disk) and write to the FD in the same manner as the CD-ROM drive 37. Similarly to the CD-ROM drive 37, 39 is a DVD-ROM (DVD-RAM) drive capable of reading from a DVD-ROM and writing to a DVD-RAM. Note that when a program for image editing is stored in a CD-ROM, FD, DVD-ROM or the like, these programs are installed in the HD 36 and transferred to the RAM 35 as necessary.

  Reference numeral 317 denotes an interface (I / F) for connecting the video camera 316 and the bus 318 to output image data input from the video camera 316 to the HD 36 or the RAM 35.

  Reference numeral 311 denotes an I / F for connecting the host computer 31 to the NIC 310 for connecting image data stored in the RAM 35, HD 36, CD-ROM 37, FD 38, DVD 39, etc. to a network such as the Internet. The host computer 31 transmits data to the Internet via the I / F 311 and receives data from the Internet.

  Reference numeral 313 denotes an I / F for connecting the mouse 314 and the keyboard 315 to the host computer 31. Various instructions input from the mouse 312 and the keyboard 315 are input to the CPU 33 via the I / F 313.

<Cryptographic processing unit and method>
Next, an encryption processing unit and method applicable to the present embodiment will be described with reference to FIG.

  FIG. 4 is a diagram for explaining the encryption processing function and method in the present embodiment. 4, 41 is an image input unit, 42 is an importance level acquisition unit, 43 is an encryption key setting unit, 44 is an encryption unit, and 45 is an image output unit.

  First, in the image input unit 41, image data to be encrypted is input. In this embodiment, moving image data that is compression-coded independently for each frame, such as Motion JPEG 2000, is used as image data. However, the present invention is not limited to this, and it is obvious that a method of independently compressing and encoding various frames such as Motion JPEG can be applied.

  When the image data input in the image input unit 41 is image data that has not been compression-encoded, the image input unit 41 executes compression-encoding processing using Motion JPEG 2000. In addition, when the input image data is compression-encoded using inter-frame correlation such as MPEG-2 or MPEG-4, the MPEG-2 or MPEG-4 is once set. The compression encoding process such as Motion JPEG 2000 may be executed again. In any case, the moving image data compressed and encoded using Motion JPEG 2000 is output from the image input unit 41.

  Next, the importance level acquisition unit 42 will be described. The importance level acquisition unit 42 receives moving image data, acquires the importance level for each frame of the input moving image data, and outputs the acquired importance level for each frame.

  Here, the importance for each frame set by the importance acquisition unit 42 will be described. In the present embodiment, at least two importance levels, that is, one of the first importance level and the second importance level is set for each frame. Hereinafter, for the sake of explanation, it is assumed that the second importance is more important than the first importance.

A method using scene change detection will be described as an example of importance acquisition processing applicable to the present embodiment. When using a scene change, the frame in which the scene change occurs is detected in the input moving image data, and the first importance is detected for the detected scene change frame, while the non-scene change frame is used. In this case, the second importance level is set. (That is, non-scene change frames are set to be more important than scene change frames.)
In this example, the scene change frame is set to be more important than the non-scene change frame. This is because the scene change frame is more effective than the non-scene change frame in order to know the outline of the video.

  As the scene change detection process, for example, compression-encoded image data is temporarily compressed and decoded, and the absolute value of each pixel is calculated between two consecutive frames. Whether the calculated value is larger than a predetermined threshold value. It is possible to apply a method of making a determination based on whether or not.

  Alternatively, the scene change detection process may be executed in advance using image data before being subjected to compression encoding, and only the result of the scene change detection process may be input to the importance level acquisition unit 42. By doing so, it is not necessary to execute a process of once compressing and decoding the compression-encoded image data for the scene change detection process, and the efficiency can be improved.

  However, the present invention is not limited to this, and it is obvious that various scene change detection processes can be applied.

  FIG. 7 shows an example of importance level acquisition processing in the present embodiment when scene change detection is used. In FIG. 7, reference numerals 71 to 79 denote frames in the moving image data. It is assumed that the moving image data has a time axis in the order of 71, 72,. Of these frames, the scene change detection process detects frames 71, 75, and 78 as scene change frames, while frames 72, 73, 74, 76, 77, and 79 are detected as non-scene change frames. The first importance W1 is set for the scene change frame, while the second importance W2 is set for the non-scene change frame.

  Next, a method of using metadata will be described as an example of another importance level acquisition process applicable to the present embodiment. When using the metadata, the metadata added in advance for each frame (or each frame group) of the image data is used, and the first importance is applied to the frame to which the predetermined metadata is added. On the other hand, the second importance is set for other frames. As metadata, for example, performers, scene contents, program names, and the like can be applied.

  In this example, it is set that the frame to which the predetermined metadata is added is more important than the frame to which the predetermined metadata is not added. For example, when the predetermined metadata is a performer, in order to search only the scenes in which the predetermined performer appears in the video, a frame to which metadata about the performer is added is necessary. It is.

  FIG. 8 shows an example of importance level acquisition processing in the present embodiment when metadata is used. In FIG. 8, reference numerals 81 to 89 indicate “scene contents” added as metadata of each frame in each frame in the moving image and in the lower column of each frame. When “person” is set as the predetermined metadata, the frames 85, 86, and 87 having the corresponding metadata have the first importance W1, while the other frames have the second importance W2. Is set.

  As described above, the example using the scene change detection and the example using the metadata have been described as examples of the importance level acquisition process applicable to the present embodiment. However, the present invention is not limited to the importance level acquisition process as described above, and it is obvious that various importance level acquisition processes can be applied.

  The importance level acquisition process described above is automatically processed in the host computer 31 by pressing the “automatic setting” button 27 in FIG. 2 after inputting the input file. ”Button 28 may be pressed by the user using mouse 314, keyboard 315, or the like.

  The details of the importance level acquisition process applicable to the present embodiment have been described above.

  Next, the encryption key setting unit 43 will be described. The encryption key setting unit 43 receives the importance for each frame, sets key data for each frame according to the input importance, and outputs the set key data for each frame.

  Here, an encryption key setting process applicable to the present embodiment will be described. In the present embodiment, an encryption key is set according to the importance acquired by the importance acquisition unit 42 in the previous stage. That is, the first encryption key is set for the first importance, while the second encryption key is set for the second importance.

  An example of the encryption key setting process in the present embodiment will be described using the examples of FIGS. 7 and 8 described above.

  In each of FIGS. 7 and 8, the first encryption key K1 is set for the first importance W1, and the second encryption key K2 is set for the second importance W2. As a result, in FIG. 7 (that is, when scene change detection is used for the importance setting process), the first encryption key K1 is set for the frames 71, 75, and 78, and the frames 72, 73, The second encryption key K2 is set for 74, 76, 77, and 79. On the other hand, in FIG. 8 (that is, when metadata is used for importance setting processing), the first encryption key K1 is set for the frames 85, 86, and 87, and the frames 81, 82, 83, A second encryption key K2 is set for 84, 88, and 89.

  The details of the key information setting process applicable to this embodiment have been described above.

  Next, the encryption unit 44 will be described. The encryption unit 44 receives moving image data and encryption key data, performs an encryption process for each frame using the input encryption key data, and outputs encrypted image data.

  In this embodiment, since encryption processing is executed with a different encryption key for each frame, in the later-described encryption / decryption processing, the correspondence between the encryption key and the frame (that is, which encryption key was used for which frame) Information). For this reason, in this embodiment, as shown in FIG. 9, corresponding key information is recorded in header information.

  Here, a recording method of key information in the present embodiment will be described with reference to FIG.

  FIG. 9A shows an example in which key information is recorded for each frame. 9, reference numerals 91 to 99 denote encoded data corresponding to the respective frames in FIG. The encoded data corresponding to each frame includes header information for recording various compression parameters and the like, and actual compressed encoded data. For example, in FIG. 9A, the fifth frame (95 in the figure) is composed of a header 910 and compressed encoded data 911. FIG. 9A shows that the key information corresponding to the fifth frame (that is, the first key information K1) is recorded in the header information of the fifth frame. Similarly, for other frames, corresponding key information is recorded in the header information of each frame.

  On the other hand, FIG. 9B shows an example in which key information is recorded in representative frames of all frames. In FIG. 9B, reference numerals 912 to 920 denote encoded data corresponding to the respective frames in FIG. The encoded data corresponding to each frame is composed of header information and compressed encoded data as in FIG. For example, when the head frame (912 in the figure) is a representative frame, key information is recorded in the header information 921 of the head frame corresponding to each frame, as shown in FIG. 9B.

  The key information to be recorded may be an identifier indicating the first key information and the second key information, or a key different from the first key information and the second key information. The first key information and the second key information may be encrypted with the information, and the encrypted first key information and second key information may be recorded.

  As described above, the method of recording the key information in the present embodiment has been described. However, the present invention is not limited to this, and it is obvious that the key information can be recorded in the compression encoded data by various methods. is there.

  In this embodiment, the encryption algorithm for the encryption process is not particularly limited, and public key encryption algorithms such as DES (Data Encryption Standard) and AES (Advanced Encryption Standard), and RSA are disclosed. Various encryption algorithms such as a key encryption algorithm can be applied.

  In this embodiment, it is not always necessary to encrypt all data (code string) corresponding to a frame, and it corresponds to a predetermined spatial region, resolution, image quality (layer), component (component), etc. in the frame. Alternatively, partial data (code string) may be selectively encrypted.

  The encryption unit 44 in this embodiment has been described above.

  Finally, the image output unit 45 outputs the moving image data encrypted by the encryption unit 44. The image output unit 45 uses the NIC 310 to transmit to the image distribution server 12 or temporarily accumulates in a storage medium such as the RAM 35, HD 36, CD 37, FD 38, DVD 39.

  The encryption process and method applicable to the present embodiment have been described above.

  Next, the encryption processing and method flow as described above will be described with reference to FIG. FIG. 5 is a flowchart for explaining an encryption process applicable to this embodiment.

  First, in step S51, importance is set for each frame for moving image data to be encrypted (input in 41 of FIG. 4) (42 of FIG. 4). Next, in step S52, encryption key data is set for each frame in accordance with the importance set in step S51 (43 in FIG. 4). In step S53, the encryption process is performed for each frame using the encryption key data set in step S52 (44 in FIG. 4).

  As described above, according to the present embodiment, it is possible to perform frame-by-frame encryption processing corresponding to the importance of each frame on moving image data that has been compression-coded for each frame.

<Encryption / Decryption Processing Unit and Method>
Next, an encryption / decryption process and method applicable to the present embodiment will be described with reference to FIG.

  FIG. 6 is a diagram for explaining the encryption / decryption function in the present embodiment. In FIG. 6, 61 is an image input unit, 62 is an encryption / decryption key setting unit, 63 is an encryption / decryption unit, and 64 is an image output unit.

  First, in the image input unit 61, image data to be encrypted / decrypted is input. The image data input here is easy to understand if it is considered as encrypted image data output from the image output unit 45 in FIG. The input image data is output to the encryption / decryption unit 63.

  Next, the encryption / decryption key setting unit 62 will be described. The encryption / decryption key setting unit 62 receives the access permission information, sets an appropriate encryption / decryption key according to the input access permission information, and outputs the set encryption / decryption key to the subsequent encryption / decryption unit 63. .

  Here, the access permission information is information that determines the degree of decryption (reproduction) of the encrypted moving image data. Here, an example in which billing information is used as access permission information will be described.

  When the billing information is used as the access permission information, the billing process is executed in the billing server 16 (FIG. 1), and the billing information is input to the encryption / decryption key setting unit 62 as the access permission information. In the encryption / decryption key setting unit 62, an encryption / decryption key is set according to the input billing information. For example, as shown in FIG. 10, when the first billing information is input, the first key information K1 is set as the encryption / decryption key, while when the second billing information is input, the first key information K1 is set as the first key information K1. Key information K1 and second key information K2 are set as encryption / decryption keys.

  In particular, in the present embodiment, it is desirable that the second key information is more difficult to obtain than the first key information from the viewpoint of appropriate access control. Therefore, when billing information is used as access permission information, the amount in the second billing information is set higher than the amount in the first billing information.

  Next, as another example of access permission information, an example in the case where viewing location information is used will be described.

  When viewing location information is used as the access permission information, the viewing location information includes an encryption / decryption key setting unit 62 where the output location of image data output from the image output unit 64 (that is, the location where the image is actually viewed) is described later. Is input. In the encryption / decryption key setting unit 62, an encryption / decryption key is set according to the input viewing location information. For example, as shown in FIG. 11, when the first viewing location information is input, the first key information K1 is set as the encryption / decryption key, while when the second viewing location information is input. Sets the first key information K1 and the second key information K2 as encryption / decryption keys.

As described above, in the present embodiment, it is desirable that the second key information is more difficult to obtain than the first key information from the viewpoint of appropriate access control. Therefore, when viewing location information is used as the access permission information, the second viewing location is set to be a more limited location than the first viewing location information. (For example, the second viewing location may be a home, and the first viewing location may be other than the home.)
It should be noted that the present invention is not limited to the access permission information as described above, and various other information such as viewer information, viewing time information, or a combination thereof can be applied. it is obvious.

  The encryption / decryption key setting unit 62 in the present embodiment has been described above.

  Next, the encryption / decryption unit 63 will be described. The encryption / decryption unit 63 receives the encrypted moving image data and the encryption / decryption key, performs encryption / decryption processing on the encrypted image data using the encryption / decryption key, and outputs the decoded moving image data. The

  The encryption / decryption processing in the present embodiment scans encrypted moving image data for each frame, specifies key data corresponding to the frame, and determines whether the specified key data is input as an encryption / decryption key. If it is determined and input, encryption / decryption processing is executed using the encryption / decryption key.

  Here, the key information corresponding to each frame (information indicating the location of the key data. For example, the file name on the server storing the key data) is encoded data by the method shown in FIG. Therefore, the key information can be obtained by analyzing the header information in the encoded data and acquiring the key data. In addition, as described above, when the first key information and the second key information are encrypted with the third key information, each key information is encrypted and decrypted using the third key information. Then, the decrypted first key information and second key information may be used.

  Note that the encryption / decryption unit 63 can output a frame that has not been subjected to the encryption / decryption process due to the absence of the corresponding key information (that is, an encrypted frame) as encrypted. It is. In this case, the moving image data reproduced in the subsequent image output unit 64 is reproduced in a state where some frames (encrypted) are scrambled. Alternatively, it is also possible to remove frames that have not been subjected to encryption / decryption processing and output only frames that have been subjected to encryption / decryption processing. In this case, the moving image data reproduced in the subsequent image output unit 64 is reproduced in a time shorter than the entire reproduction time of the moving image data (since the encrypted frame is removed).

  Finally, the image output unit 64 receives the decrypted image data, and the input moving image data is output to the monitor 32, stored in the RAM 35, HD 36, CD 37, FD 38, and DVD 39, Alternatively, the data is transferred to another host computer via the Internet using the NIC 310.

  The encryption / decryption processing and method applicable to the present embodiment have been described above.

  Next, the encryption / decryption processing and method flow as described above will be described with reference to FIG. FIG. 13 is a flowchart for explaining encryption / decryption processing applicable to this embodiment.

  First, in step S131, an encryption / decryption key is set based on the access permission information (62 in FIG. 6). In step S132, encryption / decryption processing is performed for each frame using the encryption / decryption key data set in step S131 (63 in FIG. 6).

  As described above, according to the present embodiment, encryption / decryption processing can be performed for each frame based on the access permission information.

  Heretofore, the encryption processing unit (method) and the encryption / decryption processing unit (method) applicable to the present embodiment have been described.

  Here, an example of access control that can be realized by using this embodiment will be described with reference to FIG.

  FIG. 12 is a diagram illustrating an example of access control that can be realized using the present embodiment. Here, an example in which scene change detection is used as the above-described importance level acquisition process (see FIG. 7A), and an example in which billing information is used in the encryption / decryption key setting unit 62 (see FIG. 10). It explains using.

  In the figure, 121 is image data input by the image input unit 41, 122 is the importance acquired by the importance acquisition unit 42 (here, the example shown in FIG. 7A is used), and 123. An encryption key set by the encryption key setting unit 43 and 124 is an encrypted moving image encrypted by the encryption unit 44.

  First, when neither the first billing information nor the second billing information is input to the encryption / decryption key setting unit 62 (that is, when no billing process is executed in the billing server 16), Since the encryption / decryption key is not set in the encryption / decryption key setting unit 62, the encryption / decryption processing unit 63 does not execute the encryption / decryption processing on any frame. All frames are played back in a scrambled state. Or nothing is played back.

  Next, when the first billing information is input to the encryption / decryption key setting unit 62, the encryption / decryption key setting unit 62 sets the first key information as shown in FIG. In the processing unit 63, only the scene change frame is subjected to encryption / decryption processing. As a result, in the image output unit 64, a part of the frames (shaded frames in the figure) is scrambled as shown at 126. Played. Alternatively, only the unshaded frames in the figure are played back in a short time.

  Furthermore, when the first charging information and the second charging information are input to the encryption / decryption key setting unit 62, the encryption / decryption key setting unit 62 sets the first key information as shown in FIG. And the second key information are set, and the encryption / decryption processing unit 63 performs encryption / decryption processing. As a result, the image output unit 64 reproduces all frames as indicated by 127.

  In the present embodiment, the importance level is described as two levels (that is, the first importance level and the second importance level). However, the present invention is not limited to this, and the importance level is divided into three or more levels. It is clear that it can adapt to the importance. In the present embodiment, the importance level and the number of access permission information levels are the same (both are two levels). However, the present invention is not limited to this, and the importance level and access control are performed. It is clear that the present invention can be applied even when the stages are different.

  In the following, an example will be described in which there are three levels of importance and two levels of access control. Further, an example in which billing information is used as access permission information will be described, and the importance and billing information in this case are assumed to be associated as shown in FIG. That is, the first charging information is associated with the first key information K1, while the second charging information is associated with the first key information K1, the second key information K2, and The third key information K3 is associated.

  FIG. 14 shows an example of encryption processing and encryption / decryption processing in the case where the importance level is “1”, “2”, and “3”. In the figure, 171 is image data input by the image input unit 41, 172 is the importance acquired by the importance acquisition unit 42, 173 is the encryption key set by the encryption key setting unit 43, and 174 is the encryption unit 44. It is the encryption moving image encrypted in (1).

  Here, an example is shown in which scene change detection and equidistant sampling are used as the importance level acquisition process 42 (FIG. 4). The scene change detection is the same as the processing described above, and in FIG. 14, the first frame and the tenth frame are detected as scene change frames. In the figure, the importance is shown as “1”. On the other hand, equidistant sampling is a process of extracting frames that are equally spaced in time between scene change frames. In FIG. 14, the fourth, seventh, and thirteenth frames are extracted. Has been. In the figure, the importance is indicated as “2”. Further, the remaining frames are indicated as the importance “3”.

  By setting the importance level and delivering the frames in the order of importance, the outline of the video can be known at an early stage after the start of reception, and the video quality (in this case, the motion (Smoothness) can be improved.

  Next, an encryption / decryption process for decrypting the encryption process described above will be described. In the figure, reference numeral 175 denotes that the encryption / decryption key is not set in the encryption / decryption key setting unit 62 when neither the first charging information nor the second charging information is input to the encryption / decryption key setting unit 62. Therefore, the encryption / decryption processing unit 63 does not execute the encryption / decryption processing for any frame, and as a result, the image output unit 64 reproduces all the frames in a scrambled state as indicated by 175. . Or nothing is played back.

  Next, when the first billing information is input to the encryption / decryption key setting unit 62, the encryption / decryption key setting unit 62 sets the first key information as shown in FIG. In the processing unit 63, only the scene change frame is encrypted and decrypted. As a result, in the image output unit 64, a part of frames (shaded frames in the figure) are scrambled as shown by 176. Played. Alternatively, only the unshaded frames in the figure are played back in a short time.

  Further, when the first charging information and the second charging information are input to the encryption / decryption key setting unit 62, the encryption / decryption key setting unit 62 sets the first key information as shown in FIG. The second key information and the third key information are set, and the encryption / decryption processing unit 63 performs encryption / decryption processing. As a result, the image output unit 64 displays all the frames as shown in 177. The frame is played.

  As described above, the present embodiment can be applied to a case where the number of importance levels set in the encryption processing unit is different from the number of access permission information levels set in the encryption / decryption processing unit. Thereby, at the encryption processing stage, the importance can be set independently of the access control stage for reproduction, and there is an effect that it is not necessary to consider the number of access control stages.

  In FIG. 14, it is possible to reproduce a moving image as shown by 178 by performing an encryption / decryption process on the encrypted moving image 174 using the first key information and the second key information. Is clear.

  In the present embodiment, the encryption key setting unit 43 sets the first key information K1 for the first importance W1 and the second key information W2 for the second importance W2. did. In the encryption / decryption key setting unit 62, the first key information K1 for the first billing information, the first key information K1 and the second key information K2 for the second billing information. It was set. However, since it is necessary to set two pieces of key information (that is, the first key information K1 and the second key information K2) for the second billing information, it is not efficient. In particular, as described above, it is necessary to set more key information by increasing the importance level.

  A modification of the encryption key setting unit 43, the encryption / decryption key setting unit 62, and the encryption / decryption unit 63 for solving this problem will be described with reference to FIG.

  In FIG. 16, reference numeral 141 denotes a one-way function, for example, a hash function such as SHA-1 or MD5, or encryption such as DES or AES. In the present embodiment, the encryption key setting unit 43 automatically generates the first key information K1 from the second key information K2 using the one-way function 141. The encryption / decryption key setting unit 62 sets either the first key information K1 or the second key information K2 based on the input access permission information.

  FIG. 17 and FIG. 18 show examples in which charging information and viewing location information are applied as access permission information, respectively. As shown in FIG. 17, the first key information K1 is set when the first billing information is input, and the second key information K2 is set when the second billing information is input. . In addition, as shown in FIG. 18, when the first viewer place is input, the first key information K1 is set, and when the second billing information is input, the second key information K2 is set. Set.

  The encryption / decryption key thus set is output to the encryption / decryption unit 63. When the second key information K2 is input to the encryption / decryption unit 63, the first key is generated from the second key information K2 using the one-way function 141 inside the encryption / decryption unit 63. A generation K1 is generated and used for the above-described encryption / decryption processing.

  As described above, by generating the key information using the one-way function, the number of keys to be set in the encryption / decryption key setting unit 62 can be reduced.

  Although the embodiment according to the present invention has been described above, as described above, an apparatus that encrypts and decrypts image data is a general-purpose information processing apparatus such as a normal personal computer, and operates on it. Since the present invention can be realized by a computer program, it is obvious that the present invention includes a computer program as its category. In addition, the computer program is normally stored in a computer-readable storage medium such as a CDROM, and can be executed by setting it in a corresponding drive of the computer and copying or installing it in the system. It is obvious that the present invention naturally includes such a computer-readable storage medium.

It is a figure which shows the whole system structure in embodiment. It is a figure which shows the example of the GUI screen at the time of performing the encryption process in embodiment. It is a figure which shows the host computer in embodiment. It is a figure explaining the structure of the encryption process part in embodiment. It is a flowchart of the encryption process in embodiment. It is a figure explaining the structure of the encryption / decryption process part in embodiment. It is a figure explaining an example of access control using billing information in an embodiment. It is a figure explaining an example of access control using viewing-and-listening location information in an embodiment. It is a figure explaining the recording method of key information in an embodiment. It is a figure explaining an example of the setting process of the encryption / decryption key at the time of using the accounting information in embodiment. It is a figure explaining an example of the setting process of the encryption / decryption key at the time of using viewing-and-listening place information in embodiment. It is a figure explaining an example of access control in an embodiment. It is a flowchart of the encryption / decryption process in embodiment. It is a figure explaining the example of the encryption process in case the importance level is 3, and an encryption / decryption process. It is a figure explaining the other example of the setting process of the encryption / decryption key at the time of using the accounting information in embodiment. It is a figure explaining the key generation in an embodiment. It is a figure explaining the other example of the setting process of the encryption / decryption key at the time of using the accounting information in embodiment. It is a figure explaining the other example of a setting process of the encryption / decryption key at the time of using viewing-and-listening location information in embodiment.

Claims (11)

An encryption method for encrypting image data encoded for each frame,
Importance acquisition step of acquiring the importance for each frame constituting the image data;
An encryption key setting step for setting an encryption key for each frame according to the acquired importance;
And an encryption step of performing encryption processing on the image data for each frame using the encryption key.   The information processing method according to claim 1, wherein the importance level acquisition step detects a scene change frame from the image data and acquires the level of importance for each frame according to a detection result.   The information processing method according to claim 1, wherein the importance level acquisition step acquires the importance level for each frame based on metadata added to the image data.   The importance includes at least a first importance and a second importance. In the encryption key setting step, a first encryption key is set for the first importance, and the second The information processing method according to claim 1, wherein a second encryption key is set as the importance level of.   The information processing method according to claim 1, wherein the encryption key setting step generates a first encryption key from a second encryption key using a one-way function. An information processing method for decrypting image data encrypted by the information processing method according to any one of claims 1 to 5,
An encryption / decryption key setting step for setting an encryption / decryption key according to access permission information;
And an encryption / decryption step of decrypting the image data using the set encryption / decryption key.   The information processing method according to claim 6, further comprising a billing step for performing billing processing for reproducing the image data, wherein the access permission information is billing information obtained by the billing step. An encryption device for encrypting image data encoded for each frame,
Importance acquisition means for acquiring importance for each frame constituting the image data;
An encryption key setting means for setting an encryption key for each frame according to the acquired importance,
An information processing apparatus comprising: an encryption unit that performs encryption processing on each frame of image data using the encryption key. An information processing apparatus for decoding moving image data encrypted by the information processing apparatus according to claim 8,
An encryption / decryption key setting device for setting an encryption / decryption key according to access permission information;
An information processing apparatus comprising: an encryption / decryption device that decrypts the moving image data using the set encryption / decryption key.   A computer program for executing the information processing method according to claim 1. A computer-readable storage medium storing the computer program according to claim 10.

Images