JP2014127990A - Encryption apparatus, encryption method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encryption apparatus, capable of generating moving image data that can be encrypted and decrypted when the moving image is divided.SOLUTION: An encryption unit 205 in an imaging apparatus 200 counts the number of image frames obtained by coding the moving image data by an in-frame coding method, to generate and encrypt a macro block and a rearrangement table by changing the macro block and the rearrangement table for each certain frame or uncertain frame. An image coding unit 206 adds to a frame a macro block and a rearrangement table applied to a preceding frame than the frame of concern, to code the frame at timing in which the macro block and the rearrangement table are changed among frames encrypted by the encryption unit 205.

Description

  The present invention relates to an encryption device, an encryption method, and a program for encrypting moving image data.

  Conventionally, when encrypting moving image data, there is a moving image encryption method in which moving image blocks are randomly rearranged by scrambling and reordering information corresponding to encryption key information is recorded as additional information of the moving image frame. There is also a moving image encryption method that changes the rearrangement information irregularly or periodically (see Patent Document 1). By this method, encryption can be realized by using the additional information of the moving image frame when encrypting. Further, since it is necessary to use additional information that is changed irregularly or periodically in order to perform decoding, it cannot be easily decoded unless additional information is used.

JP 2001-275111 A

  However, in the conventional moving image encryption method, when a moving image is divided, rearrangement information corresponding to some frames included in the divided latter moving image is included in the divided first moving image. Therefore, a part of the latter half of the divided moving image cannot be decrypted.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to generate moving image data that can be encrypted and decrypted when a moving image is divided.

  The encryption device according to the present invention, for the moving image data, based on the generation means for generating the encryption information at a predetermined timing while changing the encryption information, and the encryption information generated by the generation means, Encryption means for encrypting moving image data for each frame, and encryption information applied to the frame in a frame at a timing when the encryption information is changed among frames encrypted by the encryption means And encoding means for adding and encoding the encryption information applied to the frame before the frame.

  According to the present invention, even if a moving image is divided, the latter half of the divided moving image can be decrypted.

It is a figure which shows an example of schematic structure of the imaging system containing an imaging device. It is a block diagram which shows the structural example of an imaging device and PC. 6 is a flowchart illustrating an example of a shooting processing procedure according to the first embodiment. It is a flowchart which shows an example of the detailed procedure of an encryption process. It is a flowchart which shows an example of the detailed procedure of an encoding process. It is a figure explaining the macroblock before rearrangement. It is a figure explaining the macroblock after rearrangement. It is a figure explaining a macroblock rearrangement table. 4 is a flowchart illustrating an example of a reproduction processing procedure according to the first embodiment. It is a flowchart which shows an example of the detailed procedure of an image decoding process. It is a flowchart which shows an example of the detailed procedure of an encryption / decryption process. It is a figure which shows an example of schematic structure of an imaging device. 10 is a flowchart illustrating an example of a shooting processing procedure according to the second embodiment. 10 is a flowchart illustrating an example of a reproduction processing procedure according to the second embodiment. It is a flowchart which shows an example of the detailed procedure of an encryption process. It is a flowchart which shows an example of the detailed procedure of an encoding process. It is a flowchart which shows an example of the detailed procedure of an image decoding process. It is a flowchart which shows an example of the detailed procedure of an encryption / decryption process.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a diagram illustrating an example of a schematic configuration of an imaging system including an imaging apparatus according to the first embodiment.
As shown in FIG. 1, a personal computer (PC) 100 that functions as a playback device and an imaging device 200 such as a digital camera are connected via an interface 300. For example, USB (Universal Serial Bus) can be used as the interface 300, but a communication interface other than USB can also be used.

  In the first embodiment, a digital camera will be described as an example of the imaging device 200. However, the imaging device 200 according to the first embodiment can be configured by a device other than the digital camera. In addition, the imaging apparatus 200 according to the first embodiment can be configured by an apparatus having an operation mode that operates as a digital camera, such as a mobile phone with a camera function. Furthermore, in the first embodiment, the image data recorded in the imaging apparatus 200 is premised on moving image data, but the moving image encoding method uses an intra-frame encoding method, an inter-frame encoding method, or Any format such as a combination of these may be used.

FIG. 2 is a block diagram illustrating a configuration example of an imaging system including the imaging device 200 according to the first embodiment.
As illustrated in FIG. 2, the PC 100 includes a CPU (Central Processing Unit) 101, a memory 102, a communication unit 104, an image decryption unit 105, an encryption / decryption unit 106, a display unit 107, and an operation unit 108. .

  The CPU 101 is for controlling the entire PC 100. The image decoding unit 105 decodes the encoded data created by the imaging device 200 and extracts the encrypted data and user data in the picture layer. The encryption / decryption unit 106 decrypts the encrypted data extracted by the image decoding unit 105 and extracts video data. The display unit 107 is configured by a display device such as a liquid crystal display. Based on the encoded data supplied from the memory 102 or the communication unit 104, the display unit 107 is a result of processing performed by the image decoding unit 105 and the encryption / decryption unit 106. The video related to the video data is displayed. The display unit 107 can also display menu screen data stored in the memory 102 as a graphical user interface (GUI). The menu screen is for displaying a PC control screen for controlling the PC 100, a PC setting screen for changing the settings of the PC 100, and an image obtained as a result of processing by the image decoding unit 105 and the encryption / decryption unit 106. Image display screen.

  The operation unit 108 is a user interface for operating the PC 100. In addition, the operation unit 108 includes a pointing device such as a mouse (not shown), a tablet (not shown), a trackball, and a keyboard as operation means for operating the PC 100. The user can operate these pointing devices on the menu screen.

Next, the configuration of the imaging device 200 will be described.
As illustrated in FIG. 2, the imaging apparatus 200 includes a CPU 201, a memory 202, a recording unit 203, a communication unit 204, an encryption unit 205, an image encoding unit 206, a display unit 207, an operation unit 208, and an imaging unit 209. doing.

  The CPU 201 is for controlling the entire imaging apparatus 200. The memory 202 stores a computer program for controlling the imaging apparatus 200, predetermined image data to be displayed on the display unit 207, icon information, and the like. The recording unit 203 writes the encoded data created by the image encoding unit 206 in a recording medium such as a memory card (not shown). The display unit 207 is configured by a liquid crystal display or the like, and displays a video related to the video data generated by the imaging unit 209 when the operation mode of the imaging device 200 is a shooting mode. On the other hand, when the operation mode of the imaging apparatus 200 is the playback mode, the display unit 207 displays the video related to the video data played back from the recording medium.

  The encryption unit 205 divides each frame of the video data output from the imaging unit 209 into macro blocks, and rearranges the macro blocks according to the macro block rearrangement table created as the encryption information, thereby creating encrypted data. . Details of the macroblock rearrangement table will be described later in the description of FIG. The encryption unit 205 determines whether the image data encoding method of the video data is intraframe encoding or interframe encoding. Further, the encryption unit 205 counts images (frames) to be encoded by the intraframe encoding method, and changes the macroblock rearrangement table for every predetermined number of frames or for each indefinite frame. Here, the encryption unit 205 may count the time as the change timing and change the macroblock rearrangement table at regular time intervals or at indefinite time intervals.

  The image encoding unit 206 encodes the video data in which the macroblocks are rearranged by the encryption unit 205 using, for example, an MPEG encoding method, and generates encoded data. At this time, in the case of intra-frame encoding, the macroblock rearrangement table applied to the determined current frame and the macroblock rearrangement table applied to the frames up to the previous frame are displayed as user data in the picture layer. Insert into. When inserting user data, it is inserted according to the MPEG syntax.

  The operation unit 208 is a user interface for operating the imaging device 200 and has a plurality of buttons for operating the imaging device 200, and instructions from the user are input to the CPU 201 via the operation unit 208. . Each button in the operation unit 208 includes a switch, a touch panel, and the like. The operation unit 208 includes a shutter button, a power button, a start / stop button, a mode change button, a menu button, a cross button, a SET button, and the like.

  The start / stop button is a button for instructing the CPU 201 to start or temporarily stop recording of video data generated by the imaging unit 209 on a recording medium. The mode change button is a button for instructing the CPU 201 to change the operation mode of the imaging apparatus 200 to any one of the shooting mode, the playback mode, and the like. Note that shooting processing performed by the imaging unit 209 when the start / stop button is pressed when the operation mode of the imaging device 200 is the shooting mode will be described later. The menu button is a button for instructing the CPU 201 to display or hide the menu screen of the imaging apparatus 200. The menu screen of the imaging apparatus 200 includes a menu screen for controlling the imaging apparatus 200 and a menu screen for changing settings of the imaging apparatus 200. Data of these menu screens is stored in the memory 202. Has been.

  The operation unit 208 further includes a playback start button, a playback stop button, a pause button, a fast forward button, a rewind button, and the like. These buttons are buttons for instructing the CPU 201 to execute play, stop, pause, fast forward and rewind of video data recorded on the recording medium. is there.

  Next, the photographing process will be described. The shooting process is performed by pressing the start / stop button when the operation mode of the imaging apparatus 200 is in the shooting mode standby state. In the moving image shooting process, the video data output from the imaging unit 209 is encrypted by the encryption unit 205, further encoded by the image encoding unit 206, and recorded as encoded data on the recording medium by the recording unit 203. . Then, the encoded data is sent to the PC 100 via the communication unit 204. This series of processing is repeated until the start / stop button of the operation unit 208 is pressed again.

  Next, processing performed by the imaging apparatus 200 according to the first embodiment will be described with reference to FIG. FIG. 3 is a flowchart illustrating an example of a shooting processing procedure performed by the imaging apparatus 200 according to the first embodiment. 3 is a process executed when the PC 100 and the imaging apparatus 200 are connected via the interface 300 and the PC 100 and the imaging apparatus 200 are in a power-on state. The process shown in the flowchart of FIG. 3 is controlled by the CPU 201 executing a computer program stored in the memory 202.

  In FIG. 3, the shooting mode is set from the mode change button of the operation unit 208, and the process starts when the start / stop button of the operation unit 208 is pressed during shooting standby. In step S301, it is determined whether or not the start / stop button of the operation unit 208 has been pressed again. If the result of this determination is that the start / stop button has been pressed again, the shooting process is terminated. On the other hand, if the start / stop button has not been pressed again, in step S302, the imaging unit 209 performs shooting processing to create video data. Next, in step S303, the encryption unit 205 encrypts the video data to create encrypted data.

FIG. 4 is a flowchart showing an example of a detailed procedure of the encryption process performed by the encryption unit 205 in step S303 of FIG.
First, in step S401, the image encoding method of the video data output in step S302 is analyzed. In step S402, it is determined whether the image encoding method of the frame to be analyzed is an intra-frame encoding method or an inter-frame encoding method. As a result of this determination, if the interframe coding method is used, the processing is terminated.

  On the other hand, if the result of determination in step S402 is the intraframe coding method, the number of frames in the intraframe coding method is counted in step S403. In step S404, it is determined whether the counted number of frames is equal to or greater than a predetermined value. As a result of the determination, if it is greater than or equal to the predetermined value, the process proceeds to step S405, and if it is less than the predetermined value, the process proceeds to step S407.

  In step S405, a macroblock rearrangement table representing the arrangement of the macroblocks to be divided is created. In step S406, the frame count is reset to zero. Next, in step S407, macroblocks are rearranged using the macroblock rearrangement table newly or already created in step S405, encrypted data is created, and the process ends.

  Returning to the description of FIG. 3, in the next step S304, the image encoding unit 206 encodes the encrypted data using the macroblock rearrangement table to create encoded data.

FIG. 5 is a flowchart illustrating an example of a detailed procedure of the encoding process performed by the image encoding unit 206 in step S304 of FIG.
First, in step S501, the encrypted data is encoded to create encoded data. Next, in step S502, the image coding method analyzed in step S401 is referred to. In step S503, it is determined whether the target frame image coding method is an intra-frame coding method or an inter-frame coding method. As a result of this determination, if the inter-frame coding method is used, the processing is terminated as it is.

  On the other hand, if the result of determination in step S503 is that it is an intraframe coding method, processing proceeds to step S504. Then, the macroblock rearrangement table applied to the determined current frame and the macroblock rearrangement table applied to the frames up to the previous frame are added to the user data in the picture layer of the encoded data created in step S501. Record. Then, the process ends. In the case of the first frame, there is no macroblock rearrangement table applied to the frames up to the previous frame, so no recording is performed.

  Returning to the description of FIG. 3, in step S305, the recording unit 203 records the encoded data created in step S304 on a recording medium. In step S306, the recording unit 203 reads the encoded data from the recording medium, transmits the read encoded data to the PC 100 by the communication unit 204, and returns to step S301.

Next, macroblocks will be described in detail with reference to FIGS. Here, in order to simplify the description, it is assumed that the size of an image (frame) is 64 pixels × 48 pixels, and one macroblock that divides the image is 16 × 16.
FIG. 6 is a diagram illustrating a state in which an image is divided into macro blocks.
In FIG. 6, the numbers in the macroblock indicate an index representing the display position of the original image. In the first embodiment, indexes are assigned in order from the upper left to the lower right, but the index assignment rules may be anything as long as they are unified on the recording and reproduction side. FIG. 7 shows a state in which the image shown in FIG. 6 is rearranged with reference to the macroblock rearrangement table 800 shown in FIG.

Next, details of the macroblock rearrangement table 800 will be described with reference to FIG.
In the element number 801 of the macroblock rearrangement table 800, the number of macroblocks when an image is divided into macroblocks is recorded. In the example shown in FIG. 6, “12” is recorded. On the other hand, in the rearrangement index 802 of the macroblock rearrangement table 800, necessary information such as a random function for changing the index arrangement is recorded. In the example shown in FIG. 6, information on the rearrangement order of the indexes of 12 macroblocks is recorded.

  As described above, the macroblock rearrangement table 800 includes a macroblock rearrangement table applied to the current frame and a macroblock rearrangement table applied up to the previous frame. For this reason, tag data is assigned to each table and recorded in the user data in the picture layer of the encoded data. Furthermore, when the start / stop button is pressed again, the encoded data that will be the last frame of the video is created, and the macroblock rearrangement table applied to the current frame is recorded in the user data in the picture layer. You may make it do.

  Next, the reproduction process will be described. In the first embodiment, a description will be given of a reproduction process when the PC 100 side receives encoded data from the imaging apparatus 200. When the encoded data is received from the imaging apparatus 200 via the communication unit 104, the image decoding unit 105 extracts the encrypted data and the macroblock rearrangement table in the picture layer. Then, the encryption / decryption unit 106 decrypts the encrypted data based on the macroblock rearrangement table and extracts the video data. Finally, the video related to the extracted video data is displayed on the display unit 107 under the control of the CPU 101. This series of processing is repeated until no encoded data is received from the imaging apparatus 200.

  Next, processing performed by the PC 100 according to the first embodiment will be described with reference to FIG. FIG. 9 is a flowchart illustrating an example of a reproduction processing procedure performed in the PC 100 according to the first embodiment. 9 is a process executed when the PC 100 and the imaging device 200 are connected via the interface 300, and the PC 100 and the imaging device 200 are in the power-on state. Further, the processing shown in the flowchart of FIG. 9 is controlled by the CPU 101 executing a computer program stored in the memory 102.

  In FIG. 9, when encoded data is received from the imaging apparatus 200 by the communication unit 104, processing is started. In step S901, it is determined whether encoded data is no longer received from the imaging apparatus 200. If reception is completed as a result of this determination, the reproduction process is terminated. On the other hand, if reception has not ended, in step S902, the image decoding unit 105 performs image decoding processing to extract encrypted data and user data in the picture layer.

FIG. 10 is a flowchart illustrating an example of a detailed procedure of the decoding process performed by the image decoding unit 105 in step S902 of FIG.
First, in step S1001, image decoding is performed on the encoded data sent from the imaging apparatus 200, and the encrypted data (encrypted frame) and user data in the picture layer are extracted. Next, in step S1002, user data in the picture layer is analyzed. In step S1003, it is determined whether a macroblock rearrangement table exists in the user data. If the result of this determination is that there is no macroblock rearrangement table, the process ends. On the other hand, if the result of determination in step S1003 is that a macroblock rearrangement table exists, in step S1004, the macroblock rearrangement table is stored in the memory 102, and the process ends.

  Returning to the description of FIG. 9, in step S903, the encryption / decryption unit 106 performs encryption / decryption on the encrypted data to create video data.

FIG. 11 is a flowchart illustrating an example of a detailed procedure of the encryption / decryption process performed by the encryption / decryption unit 106 in step S903 of FIG.
First, in step S1101, the macro block rearrangement table is searched from the memory 102. In step S1102, it is determined whether a macroblock rearrangement table is stored. If the result of this determination is that a macroblock rearrangement table is stored, the process advances to step S1103. If the macroblock rearrangement table is not stored, the process proceeds to step S1106.

  In step S <b> 1103, it is determined whether or not an image (frame) that has been decrypted and not decrypted is stored in the memory 102. If the result of this determination is that it has been stored in the memory 102, in step S1104, the macroblocks of all the frames stored in the memory 102 are rearranged in the original order with reference to the macroblock rearrangement table, and step S1105. Proceed to

  On the other hand, if the result of determination in step S1103 is not stored in the memory 102, the macroblock rearrangement table is referred to in step S1105, and the macroblocks of the frame decoded in step S902 are rearranged to obtain video data. Create Then, the video data is stored in the memory 102, and the process ends. If the macroblocks of the frames stored in the memory 102 are rearranged in step S1105, the video data is combined into one together with the frames in which the macroblocks are rearranged in step S1106. On the other hand, if the result of determination in step S1102 is that no macroblock rearrangement table is stored, the process advances to step S1106. In step S1106, since the decrypted frame cannot be decrypted, it is stored in the memory 102, and the process ends.

  Returning to the description of FIG. 9, next, in step S <b> 904, it is determined whether or not the video data encrypted / decrypted in step S <b> 903 is stored in the memory 102. If the result of this determination is that video data is stored, the video data stored in the memory 102 is read in step S905, the video is displayed on the display unit 107, and the process returns to step S901. On the other hand, if the result of determination in step S904 is that no video data is stored, processing returns directly to step S901.

  As described above, according to the first embodiment, the previously used macroblock rearrangement table is added together with the macroblock rearrangement table of the current frame. Thereby, even when a moving image is divided, it is possible to prevent an image (frame) that cannot be reproduced from existing.

(Embodiment 2)
In the first embodiment, the method of receiving and reproducing the video data created in the imaging apparatus 200 by the PC 100 has been described. In the second embodiment, a method for reproducing video data created by the imaging apparatus 250 on the imaging apparatus 250 will be described. In the second embodiment, the description will focus on parts different from the first embodiment, and the description of the same parts as in the first embodiment will be omitted.

FIG. 12 is a block diagram illustrating a configuration example of the imaging apparatus 250 according to the second embodiment.
As illustrated in FIG. 12, the imaging device 250 includes an encryption / decryption unit 210 and an image decryption unit 211 in addition to the configuration of the imaging device 200 illustrated in the first embodiment. The image decryption unit 211 performs image decryption on the encoded data recorded on a recording medium such as a memory card (not shown) by the recording unit 203, and extracts the encrypted data and user data in the picture layer. The encryption / decryption unit 210 decrypts the encrypted data extracted by the image decoding unit 211 and extracts video data. Further, the display unit 207 displays a video related to the video data extracted by the encryption / decryption unit 210.

  Hereinafter, processing performed by the imaging apparatus 250 according to the second embodiment will be described with reference to FIG. FIG. 13 is a flowchart illustrating an example of an imaging processing procedure performed by the imaging apparatus 250 according to the second embodiment. Note that the process illustrated in the flowchart of FIG. 13 is a process executed when the imaging apparatus 250 is in the power-on state. Further, the process shown in the flowchart of FIG. 13 is controlled by the CPU 201 executing a computer program stored in the memory 202.

  In FIG. 13, the shooting mode is set from the mode change button of the operation unit 208, and the processing is started when the start / stop button of the operation unit 208 is pressed during shooting standby. A difference from the flowchart of FIG. 3 is that encoded data is not transmitted in step S106. The other processes are the same as those shown in FIG. As a result, the encoded data is recorded by the recording unit 203.

  Next, the reproduction process will be described. As described above, in the second embodiment, a process for reproducing the encoded data recorded by the recording unit 203 in the imaging apparatus 250 will be described. In the reproduction processing of the second embodiment, the encoded data is read from a recording medium (not shown) by the recording unit 203, and the encrypted data and the macroblock rearrangement table in the picture layer are extracted by the image decoding unit 211. Then, the encryption / decryption unit 210 decrypts the encrypted data based on the macroblock rearrangement table to extract the video data, and finally displays the video related to the video data on the display unit 207 under the control of the CPU 201. This series of processing is repeated until the playback stop button of the operation unit 208 is pressed again.

  Next, processing performed by the imaging apparatus 250 according to the second embodiment will be described with reference to FIG. FIG. 14 is a flowchart illustrating an example of a reproduction processing procedure performed by the imaging apparatus 250 according to the second embodiment. Note that the process illustrated in the flowchart of FIG. 14 is a process executed when the imaging apparatus 250 is in the power-on state. Further, the process shown in the flowchart of FIG. 14 is controlled by the CPU 101 executing a computer program stored in the memory 102.

  In FIG. 14, the playback mode is set from the mode change button of the operation unit 208, and the process starts when the playback start button of the operation unit 208 is pressed. In the second embodiment, in order to determine whether or not there is encoded data to be reproduced, the processes in steps S1401 and S1402 are performed instead of the process in step S901 in FIG.

  First, in step S1401, it is determined whether or not a playback stop button has been pressed during playback. If the result of this determination is that the playback stop button has been pressed, the processing is terminated. On the other hand, if the result of determination in step S1401 is that the playback stop button has not been pressed, it is determined in step S1402 whether or not the encoded data file being played has reached the end. As a result of the determination, if the end has been reached, the process is terminated, and if the end has not been reached, the process proceeds to step S902.

  In step S902, encoded data is read from the recording medium by the recording unit 203, and image decoding processing is performed by the image decoding unit 211 in the procedure shown in FIG. In step S903, the encryption / decryption unit 210 performs encryption / decryption on the encrypted data according to the procedure illustrated in FIG. 11 to generate video data. Steps S904 to S905 are the same as those in the first embodiment.

  As described above, according to the second embodiment, the video data created by the imaging device 250 can be reproduced in the imaging device 250.

(Embodiment 3)
In the first and second embodiments, the encryption unit 205 rearranges macroblocks as encryption processing. In the third embodiment, a method of performing encryption using an encryption function using an encryption key instead of rearranging macroblocks will be described. Note that the configuration of the imaging apparatus according to the third embodiment is the same as that of the first embodiment, and a description thereof will be omitted. In the third embodiment, parts different from the first and second embodiments will be described, and the description of the same parts as the first and second embodiments will be omitted.

FIG. 15 is a flowchart illustrating an example of a detailed procedure of the encryption process performed by the encryption unit 205 in step S303 of FIG.
Steps S401 to S404 are the same as those in FIG. If the result of determination in step S404 is that the number of frames in the intraframe encoding method is equal to or greater than a predetermined value, an encryption key for encrypting an image (frame) is created in step S1501. In step S406, the same processing as in step S406 of FIG. 4 is performed, and the process proceeds to step S1502. On the other hand, as a result of the determination in step S404, if the number of frames in the intraframe encoding method is less than the predetermined value, in step S1502, the encryption function is encrypted using the encryption key newly or already created in step S1501. To create encrypted data. Then, the process ends.

FIG. 16 is a flowchart illustrating an example of a detailed procedure of the encoding process performed by the image encoding unit 206 in step S304 of FIG.
Steps S501 to S503 are the same as those in FIG. In step S1601, the encryption key applied to the determined current frame and the encryption key applied to the frames up to the previous frame are recorded in the user data in the picture layer of the encoded data created in step S501. The process is terminated. In the case of the first frame, there is no encryption key applied to the frames up to the previous frame, and no recording is performed.

  As for the reproduction process, reproduction is performed according to the procedure shown in FIG. At this time, in step S902 of FIG. 9, image decoding is performed according to the flowchart shown in FIG. In step S903 in FIG. 9, encryption / decryption is performed according to the flowchart shown in FIG.

FIG. 17 is a flowchart illustrating an example of a detailed procedure of the decoding process performed by the image decoding unit 105 in step S902 of FIG.
Step S1001 is the same as step S1001 of FIG. In step S1701, user data in the picture layer is analyzed. In step S1702, it is determined whether an encryption key exists in the user data. If the result of this determination is that there is no encryption key, the process ends. On the other hand, if the result of determination in step S1702 is that there is an encryption key, in step S1703, the encryption key is stored in the memory 102, and the process ends.

FIG. 18 is a flowchart illustrating an example of a detailed procedure of the encryption / decryption process performed by the encryption / decryption unit 106 in step S903 of FIG.
First, in step S1801, the encryption key is searched from the memory 102. In step S1802, it is determined whether an encryption key is stored. As a result of this determination, if an encryption key is stored, the process proceeds to step S1103. If an encryption key is not stored, the process proceeds to step S1106.

  In step S <b> 1103, it is determined whether or not an image (frame) that has been decrypted and not decrypted is stored in the memory 102. If the result of this determination is that it has been stored in the memory 102, in step S1803, all frames stored in the memory 102 with reference to the encryption key are decrypted by an encryption function using the encryption key, and step S1803 is executed. The process proceeds to S1804.

  On the other hand, if it is not stored in the memory 102 as a result of the determination in step S1103, in step S1804, the frame decoded in step S902 is decrypted with an encryption function using an encryption key to generate video data. To do. Then, the video data is stored in the memory 102, and the process ends. If the frame stored in the memory 102 is encrypted / decrypted in step S1804, the video data is combined into one together with the frame encrypted / decrypted in step S1804. On the other hand, if the result of determination in step S1802 is that no encryption key is stored, processing proceeds to step S1106. In step S1106, since the decrypted frame cannot be decrypted, it is stored in the memory 102, and the process ends.

  As described above, according to the third embodiment, the encryption processing by the encryption unit 205 of the imaging apparatus 200 can be realized by a method using an encryption function using an encryption key instead of rearranging macroblocks. The third embodiment can also be realized by replacing the imaging device 200 with the imaging device 250 according to the second embodiment.

(Embodiment 4)
Various functions and processes described in the first to third embodiments can be realized by a personal computer, a microcomputer, a CPU (Central Processing Unit), or the like using software such as a computer program. Hereinafter, in the fourth embodiment, a personal computer, a microcomputer, a CPU, and the like are referred to as a “computer”. In the fourth embodiment, software such as a computer program for realizing the various functions and processes described in the above embodiments is referred to as “predetermined software”.
Various functions and processes described in the first to third embodiments are realized by a computer executing predetermined software. In this case, the predetermined software is supplied to the computer via a computer-readable recording medium. The computer-readable recording medium in the fourth embodiment includes a hard disk device, an optical disk, a CD-ROM, a CD-R, a memory card, a ROM, a RAM, and the like. In addition, the computer-readable recording medium according to the fourth embodiment is a non-transitory recording medium.

205 Encryption Unit 206 Image Encoding Unit

Claims (9)

Generating means for generating encryption information at a predetermined timing while changing the encryption information for the video data;
An encryption unit that encrypts the moving image data for each frame based on the encryption information generated by the generation unit;
Of the frames encrypted by the encryption means, the frame at the timing when the encryption information is changed is applied to the encryption information applied to the frame and the frame before the frame. An encryption apparatus comprising: encoding means for adding and encoding encryption information.   The encryption apparatus according to claim 1, wherein the generation unit generates encryption information for each predetermined number of frames.   The encryption apparatus according to claim 1, wherein the generation unit generates encryption information at regular time intervals. The generation means generates a table for rearranging macroblocks as the encryption information,
The encryption apparatus according to any one of claims 1 to 3, wherein the encryption unit performs encryption by rearranging macroblocks according to the table. The generation means generates an encryption key as the encryption information,
The encryption apparatus according to any one of claims 1 to 3, wherein the encryption unit performs encryption by an encryption function using the encryption key.   The encryption apparatus according to claim 1, wherein the encoding unit adds encryption information to a frame using an intra-frame encoding method.   The encryption apparatus according to any one of claims 1 to 6, wherein the encoding unit performs encoding by an intra-frame encoding scheme or an inter-frame encoding scheme. A generation step for generating encryption information at a predetermined timing while changing encryption information for video data;
An encryption step for encrypting the video data for each frame based on the encryption information generated in the generation step;
Among the frames encrypted in the encryption step, the encryption information applied to the frame and the frame before the frame are applied to the frame at the timing when the encryption information is changed. An encryption method comprising: an encoding step of encoding by adding encryption information. A generation step for generating encryption information at a predetermined timing while changing encryption information for video data;
An encryption step for encrypting the video data for each frame based on the encryption information generated in the generation step;
Among the frames encrypted in the encryption step, the encryption information applied to the frame and the frame before the frame are applied to the frame at the timing when the encryption information is changed. A program for causing a computer to execute an encoding step of encoding by adding encryption information.

Images