JP4536011B2 - Data storage device and encryption key storage method - Google Patents

Description

  The present invention relates to an apparatus for encrypting and storing data such as video and audio provided through digital broadcasting or a network.

There has been provided an apparatus capable of recording video data of a broadcast program provided by digital broadcasting (see Patent Documents 1 and 2). In this type of recording device, the video data is encrypted and stored with an encryption key unique to the device in order to prevent unauthorized copying of the recorded video data due to copyright. In order to reproduce the stored video data, the encryption key used at the time of encryption is used. The encryption key is usually stored in a nonvolatile memory typified by a flash memory.
JP 2001-45432 A JP-A-6-78304

  Recent recording apparatuses are equipped with a time shift viewing mode. In the time shift viewing mode, the video data of the currently viewed program is continuously stored in a temporary storage unit such as a buffer. Also in the temporary recording in the time shift viewing mode, an encryption key for encrypting the video data is generated and stored in the nonvolatile memory. The video data stored in the buffer is saved in the storage unit only when a save instruction is given by the user. If no such save instruction is given, the video data It is automatically deleted from the buffer when the shift viewing mode is canceled. As described above, in the time-shift viewing mode, when no save instruction is given, useless writing of the encryption key to the nonvolatile memory is performed.

  A nonvolatile memory such as a flash memory has a limit on the number of times it can be rewritten. Therefore, it is necessary to avoid the unnecessary writing of the encryption key to the nonvolatile memory as described above. However, the conventional recording apparatus described above has not been configured to suppress such useless writing of the encryption key to the nonvolatile memory. For this reason, when the useless writing of the encryption key to the nonvolatile memory is frequently performed, the number of times of rewriting of the nonvolatile memory approaches the limit value before the expected lifetime of the device.

  An object of the present invention is to provide a data storage device that solves the above-described problems and can suppress useless writing of an encryption key to a nonvolatile memory.

To achieve the above object, the present invention includes a storage unit for storing the data supplied from the external (e.g., video data of a broadcast program), the encryption key generation unit for generating an encryption key, said encryption key generation a volatile memory which encryption key is stored which is generated by the parts, before SL using encryption key, comprising: a data processing unit for encrypting the data supplied from the outside, the, in the data processing unit only when the encrypted data is stored in the storage unit, it is the encryption key used to encrypt the data to be moved from said volatile memory, separately in the nonvolatile memory provided with the storage unit It is characterized by.

  According to the above configuration, the encryption key used for data encryption is once stored in a volatile memory with no limit on the number of data rewrites, and only when the encrypted data is stored in the storage unit. The encryption key is moved from the volatile memory to the nonvolatile memory. The encryption key used for encrypting the data that is not stored in the storage unit (specifically, the video data automatically deleted from the buffer when the time-shift viewing mode is canceled) is changed from the volatile memory to the nonvolatile memory. Will not be moved to.

Another aspect of the present invention includes a storage unit for storing the data supplied from the external, and a buffer for temporarily storing the data supplied from the outside, an encryption key to generate the encryption key a generating unit, a volatile memory in which the encryption key encryption key generated by the generator is stored, before SL using encryption key, a data processing unit for encrypting the data supplied from the outside, the has, if the encrypted by the data processing unit data has been stored in the storage unit, the encryption key used for encryption of the data is stored in provided separately from the nonvolatile memory and the storage unit, If encrypted data by the data processing unit is stored in the buffer, the encryption key used for encryption of the data is characterized in that it is stored in the volatile memory.

  Even in the above configuration, the encryption key used for encrypting the data temporarily stored in the buffer but not stored in the storage unit is not stored in the nonvolatile memory.

  According to the present invention, an encryption key used for encryption of data that has not been saved (for example, video data automatically deleted from the buffer when the time-shift viewing mode is canceled) is stored in the nonvolatile memory. Therefore, useless writing of the encryption key to the nonvolatile memory can be suppressed accordingly.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a main part of a recording apparatus according to an embodiment of the present invention. Referring to FIG. 1, the recording apparatus includes an input unit 1, a recording processing unit 2, a recording processing determination unit 3, a storage unit 4, a buffer 5, an encryption key writing unit 6, an encryption key generation unit 7, a volatile memory 8, And a nonvolatile memory 9.

  The input unit 1 is an operation for operating the recording device, for example, setting or canceling various modes such as a recording mode and a time shift viewing mode, and video data temporarily stored in the time shift viewing mode (temporary recording data). This is a part where an operation for saving video, an operation for deleting recorded video, and the like are performed. The input unit 1 includes, for example, a remote controller (hereinafter simply referred to as a remote controller) provided with a plurality of buttons, and an input device such as a keyboard and a mouse.

  When an operation for shifting to the recording mode is performed, a recording instruction signal and a recording storage instruction signal are supplied from the input unit 1 to the recording processing unit 2. When an operation for shifting to the time shift viewing mode is performed, a temporary recording instruction signal is supplied from the input unit 1 to the recording processing unit 2. When an operation for storing temporary recording data is performed in the time-shift viewing mode, an encryption key movement signal and a temporary recording storage instruction signal are supplied from the input unit 1 to the recording processing unit 2. When an operation for deleting the recorded video data is performed, a recorded video deletion instruction signal is supplied from the input unit 1 to the recording processing unit 2. When an operation for canceling the time shift viewing mode is performed, a temporarily recorded video deletion instruction signal is supplied from the input unit 1 to the recording processing unit 2.

  The recording processing unit 2 accepts an input from the input unit 1 and performs a mode determination of a recording mode or a time-shifted viewing mode, stores video data supplied from the outside in the storage unit 4 or the buffer 5, The video data stored in the unit 4 is deleted. Specifically, external video data is video data from a tuner for digital broadcasting. The buffer 5 temporarily stores video data in the time shift viewing mode. In the storage unit 4, video data is stored in the recording mode, and temporary recording data instructed to be stored is stored. When storing the video data in the storage unit 4 or the buffer 5, the recording processing unit 2 supplies an encryption key generation instruction signal to the encryption key generation unit 7 and uses the encryption key generated by the encryption key generation unit 7. Then, the video data is encrypted, or the recording / storage instruction signal or the temporary recording / storage instruction signal from the input unit 1 is transferred to the recording process determination unit 3.

  Further, the recording processing unit 2 has table information in which video identification information that can identify video data is associated with encryption key identification information that can identify an encryption key used when encrypting the video data. When the recording / saving instruction signal or the temporary recording / saving instruction signal is transferred, the table information is referred to and the encryption key identification information of the used encryption key is supplied to the recording process determination unit 3. Further, the recording processing unit 2 deletes the corresponding video data from the video data stored in the storage unit 4 in accordance with the recorded video deletion instruction signal from the input unit 1, and deletes the video data by referring to the table information. The encryption key identification information of the encryption key used for encrypting the video data is acquired, and the recorded video deletion instruction signal from the input unit 1 is supplied to the recording process determination unit 3 together with the acquired encryption key identification information. Further, the recording processing unit 2 deletes the temporary recording data stored in the buffer 5 in accordance with the temporary recording video deletion instruction signal from the input unit 1, and refers to the table information to encrypt the deleted temporary recording data. The encryption key identification information of the encryption key used for the conversion is acquired, and a temporary recording video deletion instruction signal from the input unit 1 is supplied to the recording process determination unit 3 together with the acquired encryption key identification information.

  When the encryption key generation unit 7 receives the encryption key generation instruction signal from the recording processing unit 2, the encryption key generation unit 7 generates an encryption key. A known encryption key generation technique using a random number or the like can be applied to the generation of the encryption key. The volatile memory 8 is for temporarily storing the encryption key generated by the encryption key generation unit 7. The encryption key generation unit 7 stores the generated encryption key in the volatile memory 8 in association with encryption key identification information that can identify the encryption key.

  When receiving the recording saving instruction signal or the temporary recording saving instruction signal, the recording process determination unit 3 receives an encryption key movement instruction signal for moving the encryption key stored in the volatile memory 8 to the nonvolatile memory 9. The encryption key identification information supplied from the recording processing unit 2 is supplied to the encryption key writing unit 6. In addition, when receiving the recorded video deletion instruction signal, the recording process determination unit 3 is supplied with an encryption key deletion instruction signal for deleting the encryption key stored in the nonvolatile memory 9 from the recording processing unit 2. It is supplied to the encryption key writing unit 6 together with the encryption key identification information. Furthermore, when receiving the temporarily recorded video deletion instruction signal, the recording process determination unit 3 supplies an encryption key deletion instruction signal for deleting the encryption key stored in the volatile memory 8 from the recording processing unit 2. It is supplied to the encryption key writing unit 6 together with the encrypted encryption key identification information.

  When the encryption key writing unit 6 receives the encryption key movement instruction signal and the encryption key identification information from the recording process determination unit 3, the encryption key writing unit 6 uses the received encryption key identification information among the encryption keys stored in the volatile memory 8. The encryption key specified based on this is moved to the nonvolatile memory 9. In addition, when the encryption key writing unit 6 receives the encryption key deletion instruction signal and the encryption key identification information from the recording process determination unit 3, the encryption key writing unit 6 includes the encryption key stored in the volatile memory 8 or the nonvolatile memory 9. The encryption key specified based on the received encryption key identification information is deleted.

  The nonvolatile memory 9 is a semiconductor memory typified by a flash memory and has a limited number of rewrites.

  Next, encryption key storage processing performed in the recording apparatus of the present embodiment will be described. In the following description, the normal recording mode means that the recording device is turned on and the recording processing unit receives the fact that the user has pressed the input unit such as the recording button on the remote control (recording instruction signal). It means a state in which video data recording (storage in a storage unit) is started. In the time-shift viewing mode, the recording device is turned on, and the recording processing unit starts to temporarily record (store in the buffer) video data supplied to the device from the outside such as a digital broadcasting tuner. It means the state to do. When the mode shifts to the time-shift viewing mode, temporary recording is started. The transition to the time shift viewing mode is performed when the recording processing unit receives a temporary recording instruction signal from the input unit. The recording processing unit stores a flag indicating whether or not to shift to the time-shifted viewing mode in advance in some memory, and after the device is turned on, the recording processing unit checks the presence / absence flag of the memory and shifts to the time-shifted viewing mode. You may make it do. Also, in the time-shifted viewing mode, when the user presses an input unit such as a recording button on the remote controller (temporary recording save instruction signal), the video processing unit temporarily records the video data (memory unit). Storage) can be started.

  The encryption key storage process includes an encryption key storage process and an encryption key deletion process. FIG. 2 shows a basic flow of the encryption key storing process.

  Referring to FIG. 2, first, the recording processing unit 2 determines whether there is a recording instruction based on the input from the input unit 1 (step S10). If there is a recording instruction, the normal recording mode is set (step S11). When there is no recording instruction, the recording processing unit 2 further determines whether or not the time shift viewing mode is set based on the input from the input unit 1 (step S12).

  If the normal recording mode is set, then the recording processing unit 2 transmits an encryption key generation instruction signal to the encryption key generation unit 7. Upon receiving the encryption key generation instruction signal, the encryption key generation unit 7 generates an encryption key and stores the generated encryption key in the volatile memory 8 (step S13). Next, the recording processing unit 2 encrypts the video data using the encryption key generated by the encryption key generation unit 7 and stores the encrypted video data in the storage unit 4, and records the recording save instruction signal from the input unit 1. 3 (step S14). At the time of transferring the recording / saving instruction signal, the recording processing unit 2 supplies the identification information of the encryption key used for encrypting the video data to the recording processing determination unit 3.

  The recording process determination unit 3 that has received the recording save instruction signal and the encryption key identification information supplies the encryption key movement instruction signal to the encryption key writing unit 6 together with the received encryption key identification information. The encryption key writing unit 6 that has received the encryption key move instruction signal and the encryption key identification information stores the encryption key specified based on the received encryption key identification information out of the encryption keys stored in the volatile memory 8. Move to the memory 9 (step S15).

  When the time shift viewing mode is set, the recording processing unit 2 transmits an encryption key generation instruction signal to the encryption key generation unit 7. The encryption key generation unit 7 that has received the encryption key generation instruction signal generates an encryption key, and stores the generated encryption key in the volatile memory 8 (step S16). Next, the recording processing unit 2 encrypts the video data using the encryption key generated by the encryption key generation unit 7 and temporarily stores it in the buffer 5 (step S17). Next, the recording processing unit 2 determines whether or not there is a recording instruction (temporary recording storage instruction) based on the input from the input unit 1 (step S18). When there is a recording instruction (temporary recording storage instruction), the recording processing unit 2 moves the temporary recording data stored in the buffer 5 to the storage unit 4 and changes the recording destination of the video data to the recording unit 4. (Step S19). Next, the recording processing unit 2 encrypts the video data using the encryption key generated by the encryption key generation unit 7 and stores it in the storage unit 4, and determines the recording process instruction signal from the input unit 1 for the recording process. Transfer to the unit 3 (step S20). At the time of transferring the temporary recording / saving instruction signal, the recording processing unit 2 supplies the identification information of the encryption key used for encrypting the video data to the recording processing determination unit 3.

  The recording process determination unit 3 that has received the temporary recording save instruction signal and the encryption key identification information supplies the encryption key movement instruction signal to the encryption key writing unit 6 together with the received encryption key identification information. The encryption key writing unit 6 that has received the encryption key move instruction signal and the encryption key identification information stores the encryption key specified based on the received encryption key identification information out of the encryption keys stored in the volatile memory 8. Move to the memory 9 (step S21).

  The signals supplied from the input unit in step S10 and step S18 are the same, and the recording instruction or the temporary recording storage is based on whether the recording processing unit or the recording process determining unit is instructed to shift to the time-shifted viewing mode. You may determine whether it is an instruction.

  Next, the encryption key deletion process will be described. FIG. 3 shows a basic flow of the encryption key erasure process.

  Referring to FIG. 3, first, the recording processing unit 2 determines whether or not the time shift viewing mode is set based on the input from the input unit 1 (step S30). If it is determined that the mode is not the time shift viewing mode, then the recording processing unit 2 determines whether or not there is a video erasure instruction based on the input from the input unit 1 (step S31). When there is a video erasure instruction, the recording processing unit 2 deletes the corresponding video data from the video data stored in the storage unit 4 in accordance with the recorded video deletion instruction signal from the input unit 1 (step S32). . Next, the recording processing unit 2 refers to the table information, acquires the encryption key identification information of the encryption key used to encrypt the deleted video data, and inputs the input unit 1 together with the acquired encryption key identification information. Is supplied to the recording process determination unit 3. The recording process determination unit 3 that has received the recorded video deletion instruction signal and the encryption key identification information supplies the encryption key deletion instruction signal to the encryption key writing unit 6 together with the encryption key identification information supplied from the recording processing unit 2. . The encryption key writing unit 6 that has received the encryption key deletion instruction signal and the encryption key identification information deletes the encryption key specified based on the received encryption key identification information from among the encryption keys stored in the nonvolatile memory 9. (Step S33).

  If it is determined in step S30 that the time-shifted viewing mode is set, then the recording processing unit 2 determines whether the time-shifted viewing mode has been canceled based on the input from the input unit 1 (step S30). S34). If it is determined that the time shift viewing mode has been canceled, the recording processing unit 2 deletes the temporary recording data stored in the buffer 5 in accordance with the temporary recording video deletion instruction signal from the input unit 1 (step S35). Next, the recording processing unit 2 refers to the table information, acquires the encryption key identification information of the encryption key used for encrypting the deleted temporary recording data, and inputs the encrypted key identification information together with the acquired encryption key identification information. 1 is supplied to the recording process determination unit 3. The recording process determination unit 3 that has received the temporarily recorded video deletion instruction signal and the encryption key identification information supplies the encryption key deletion instruction signal to the encryption key writing unit 6 together with the encryption key identification information supplied from the recording processing unit 2. To do. The encryption key writing unit 6 that has received the encryption key deletion instruction signal and the encryption key identification information deletes the encryption key specified based on the received encryption key identification information from among the encryption keys stored in the volatile memory 8. (Step S36).

  Next, the operation of each component unit based on the above-described encryption key storing process will be specifically described separately for each mode of the normal recording mode and the time shift viewing mode.

(1) Operation in normal recording mode:
The operation in the normal recording mode corresponds to an operation when recording is started by pressing a recording button provided in the input unit 1 or when recording is started at a time set using the recording reservation function.

  (1-1) Upon receiving a recording instruction signal that is an instruction to start recording from the input unit 1, the recording processing unit 2 transmits an encryption key generation instruction signal to the encryption key generation unit 7.

  (1-2) Upon receiving the encryption key generation instruction signal, the encryption key generation unit 7 generates an encryption key and stores it in the volatile memory 8.

  (1-3) The recording processing unit 2 encrypts the video data of the broadcast program supplied from the outside using the encryption key generated by the encryption key generation unit 7 based on the recording storage instruction signal from the input unit 1. And stored in the storage unit 4.

  (1-4) The recording processing unit 2 transfers the recording storage instruction signal from the input unit 1 to the recording processing determination unit 3.

  (1-5) Upon receiving the recording saving instruction signal, the recording process determination unit 3 sends the encryption key used for encrypting the video data stored in the storage unit 4 to the encryption key writing unit 6 in the volatile memory 8. An encryption key move instruction signal for moving from to the non-volatile memory 9 is transmitted.

  (1-6) When receiving the encryption key movement instruction signal, the encryption key writing unit 6 moves the encryption key from the volatile memory 8 to the nonvolatile memory 9.

  (1-7) When receiving the recorded video deletion instruction signal for deleting the recorded video data from the input unit 1, the recording processing unit 2 deletes the corresponding video data from the video data stored in the storage unit 4. To do.

  (1-8) The recording processing unit 2 transfers the recorded video deletion instruction signal from the input unit 1 to the recording processing determination unit 3.

  (1-9) Upon receiving the recorded video deletion instruction signal, the recording process determination unit 3 deletes the encryption key used for encrypting the deleted video data from the nonvolatile memory 9 to the encryption key writing unit 6. For this purpose, an encryption key deletion instruction signal is transmitted.

  (1-10) When receiving the encryption key deletion instruction signal, the encryption key writing unit 6 deletes the encryption key from the nonvolatile memory 9.

(2) Operation in time shift viewing mode:
(2-1) Upon receiving a temporary recording instruction signal that is an instruction to start recording from the input unit 1, the recording processing unit 2 transmits an encryption key generation instruction signal to the encryption key generation unit 7.

  (2-2) Upon receiving the encryption key generation instruction signal, the encryption key generation unit 7 generates an encryption key and stores it in the volatile memory 8.

  (2-3) The recording processing unit 2 uses the encryption key generated by the encryption key generation unit 7 for the video data of the broadcast program supplied from the outside based on the temporary recording storage instruction signal from the input unit 1. It is encrypted and temporarily stored in the buffer 5.

  (2-4) The recording processing unit 2 transfers the temporary recording storage instruction signal from the input unit 1 to the recording process determination unit 3.

  (2-5) Upon receiving the temporary recording save instruction signal, the recording process determination unit 3 sends the encryption key used for encrypting the video data stored in the buffer 5 to the volatile memory 8 to the encryption key writing unit 6. An encryption key move instruction signal for moving from to the non-volatile memory 9 is transmitted.

  (2-6) When receiving the encryption key move instruction signal, the encryption key writing unit 6 moves the encryption key from the volatile memory 8 to the nonvolatile memory 9.

  (2-7) When receiving the temporarily recorded video deletion instruction signal for deleting the temporarily recorded video data from the input unit 1, the recording processing unit 2 selects the corresponding video data from the video data stored in the buffer 5. delete.

  (2-8) The recording processing unit 2 transfers the temporarily recorded video deletion instruction signal from the input unit 1 to the recording processing determination unit 3.

  (2-9) Upon receiving the temporarily recorded video deletion instruction signal, the recording process determination unit 3 deletes the encryption key used for encrypting the deleted video data from the volatile memory 8 to the encryption key writing unit 6. To transmit an encryption key deletion instruction signal.

  (2-10) Upon receiving the encryption key deletion instruction signal, the encryption key writing unit 6 deletes the encryption key from the volatile memory 8.

  In the recording apparatus of the present embodiment, when reproducing the video data stored in the storage unit 4, the encryption key stored in the nonvolatile memory 9 is used. In the time shift viewing mode, when reproducing the temporarily recorded data stored in the buffer 5, the encryption key stored in the volatile memory 8 is used.

  According to the recording apparatus of the present embodiment described above, the encryption key generated by the encryption key generation unit 7 is temporarily stored in the volatile memory 8 with no limit on the number of data rewrites, and the encrypted video data is stored. Only when stored in the unit 4, the encryption key used to encrypt the video data is moved from the volatile memory 8 to the nonvolatile memory 9. The encryption key used for encrypting the video data that is not stored in the storage unit 4 (specifically, the video data that is not instructed to be stored among the video data stored in the buffer 5) is the volatile memory 8 To the non-volatile memory 9. As described above, since the encryption key used for encrypting the video data for which no storage instruction has been issued is not stored in the nonvolatile memory 9, useless writing of the encryption key to the nonvolatile memory 9 is made accordingly. Can be suppressed.

  The recording apparatus according to the present embodiment described above is an example of the present invention, and the configuration and operation of the present invention are such that the use of a volatile memory suppresses unnecessary writing of an encryption key to a nonvolatile memory. Changes can be made as appropriate without departing from the spirit of the invention.

  For example, in the configuration shown in FIG. 1, the recording processing unit 2 and the recording processing determination unit 3 are provided separately. However, the recording processing unit 2 and the recording processing determination unit 3 are configured by one data processing unit. Also good.

  Moreover, although the memory | storage part 4 and the buffer 5 are provided separately, you may provide the memory area corresponding to these memory | storage parts 4 and the buffer 5 in the memory area in one memory | storage device (for example, hard disk).

  Further, the encryption key generation unit 7 may generate different encryption keys for each broadcast program and store them in the volatile memory 8. Normally, video data of a broadcast program provided by digital broadcasting includes a signal indicating the start and end of the broadcast program, and the recording processing unit 2 determines the start and end of the broadcast program based on this signal. To do. Based on this determination, the recording processing unit 2 supplies an encryption key generation instruction signal to the encryption key generation unit 7 so that the encryption key generation unit 7 generates a different encryption key for each broadcast program.

  Furthermore, when the temporarily recorded data stored in the buffer 6 is stored in the storage unit 4 and then the storage destination of the video data is changed to the storage unit 4, the video data stored in the storage unit 4 after the storage destination is switched is stored. The encryption key used for encryption may be different from the encryption key used for encryption of the video data stored in the storage unit 4 after the storage destination is switched.

  Furthermore, the encryption key writing unit 6 may execute the encryption key transfer from the volatile memory 8 to the nonvolatile memory 9 at a timing when the supply of power to the volatile memory 8 is interrupted. In this case, when an input operation for turning off the power of the recording apparatus is performed at the input unit 1, a power cutoff signal is supplied from the input unit 1 to the recording process determination unit 3 through the recording processing unit 2. . Then, the recording process determination unit 3 supplies the encryption key moving instruction signal to the encryption key writing unit 6 at the timing when the power cutoff signal is received. Normally, the operation of the encryption key writing unit 6 is performed under the control of the control unit (CPU). Therefore, according to the configuration in which the encryption key is transferred from the volatile memory 8 to the nonvolatile memory 9 at the timing when the supply of power to the volatile memory 8 is cut off, the video data is stored in the storage unit 4. Each time the encryption key is transferred from the volatile memory 8 to the nonvolatile memory 9, the burden on the control unit (CPU) can be reduced.

  Further, the normal recording mode and the time shift viewing mode may be determined based on a flag indicating whether or not these modes are executed. In addition, the recording processing unit 2 may monitor the state of the flag corresponding to each instruction signal of the recording instruction signal, the recording / storage instruction signal, the temporary recording instruction signal, and the temporary recording / storage instruction signal.

  Further, in the configuration shown in FIG. 1, the input unit 1, the recording processing unit 2, the recording processing determination unit 3, the storage unit 4, and the buffer 5 are provided on the substrate on the apparatus main body side, the encryption key writing unit 6, the encryption key generation The unit 7, the volatile memory 8, and the nonvolatile memory 9 may be provided on a substrate (board) that can be attached to the apparatus.

  Furthermore, the data to be encrypted is not limited to video data. It is good also as a structure which encrypts and preserve | saves other data, such as an audio | voice.

  When the video data is encrypted and stored in the storage unit 4 in the normal recording mode, the encryption key generation unit 7 directly stores the encryption key generated for the encryption of the video data in the nonvolatile memory 9. You may make it write.

  As described above, the recording apparatus for recording a broadcast program provided through digital broadcasting has been described as an embodiment of the present invention. In addition to this, a computer system (for example, data such as audio and video) distributed via a network (for example, The present invention can also be applied to a personal computer. In this case, encryption key storage processing is executed for data distributed by streaming through the network (specifically, data distributed by multicast).

  The present invention can be applied to a recording apparatus (such as a hard disk recorder) or a personal computer that includes a tuner that supports digital broadcasting, and can also be applied to a computer system that distributes content and data through a network.

It is a block diagram which shows the structure of the principal part of the video recording apparatus which is one Embodiment of this invention. It is a flowchart which shows the basic flow of the encryption key storage process performed in the video recording apparatus shown in FIG. It is a flowchart which shows the basic flow of the encryption key deletion process performed in the video recording apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input part 2 Recording process part 3 Recording process judgment part 4 Storage part 5 Buffer 6 Encryption key writing part 7 Encryption key generation part 8 Volatile memory 9 Non-volatile memory

Claims (23)

A storage unit for storing the data supplied from the external,
An encryption key generation unit for generating an encryption key;
A volatile memory in which the encryption key generated by the encryption key generation unit is stored;
Before SL using encryption key, comprising: a data processing unit for encrypting the data supplied from the outside, the,
Wherein the data processing unit only when the encrypted data is stored in the storage unit, the encryption key used to encrypt the data from the volatile memory, nonvolatile memory provided separately from the storage unit A data storage device which is moved to   The data storage device according to claim 1, wherein the data supplied from the outside is video data of a broadcast program. An input unit;
When the recording instruction signal for recording the video data is supplied from the input unit, the data processing unit encrypts the video data using the encryption key generated by the encryption key generation unit and stores the video data A recording processing unit to be stored in the unit,
When the image data that has been encrypted is stored in the storage unit, the encryption key used to encrypt the video data said stored is moved from the volatile memory to the non-volatile memory, according to claim 2 The data storage device described in 1. Further comprising a buffer;
The recording processing unit encrypts the video data using the encryption key generated by the encryption key generation unit when a temporary recording instruction signal for temporarily recording the video data is supplied from the input unit. When the temporary recording save instruction signal for saving the temporarily recorded video data stored in the buffer is supplied from the input unit, the temporary recorded video data is transferred from the buffer to the storage unit. Move and
When the front Symbol temporary recorded video data is stored in the storage unit, the encryption key used to encrypt the video data said stored is moved from the volatile memory to the non-volatile memory, according to claim 3 Data storage device. Further comprising a buffer;
The recording processing unit encrypts the video data using the encryption key generated by the encryption key generation unit when a temporary recording instruction signal for temporarily recording the video data is supplied from the input unit. Stored in the buffer as temporarily recorded video data,
The data storage device according to claim 3, wherein the encryption key generation unit stores the generated encryption key in the volatile memory. A storage unit for storing the data supplied from the external,
A buffer for temporarily storing externally supplied data;
An encryption key generation unit for generating an encryption key;
A volatile memory in which the encryption key generated by the encryption key generation unit is stored;
Before SL using encryption key, comprising: a data processing unit for encrypting the data supplied from the outside, the,
If encrypted data by the data processing unit is stored in the storage unit, the encryption key used for encryption of the data is stored in provided separately from the non-volatile memory and said storage unit, said data processing when encrypted data is stored in the buffer section, the encryption key used for encryption of the data the data storage device characterized in that it is stored in the volatile memory.   The data storage device according to claim 6, wherein the data supplied from the outside is video data of a broadcast program. An input unit;
When the recording instruction signal for recording the video data is supplied from the input unit, the data processing unit encrypts the video data using the encryption key generated by the encryption key generation unit and stores the video data A recording processing unit to be stored in the unit,
When the encrypted video data is stored in the storage unit, the encryption key writing unit stores an encryption key used for encrypting the stored video data in the nonvolatile memory,
The recording processing unit encrypts the video data using the encryption key generated by the encryption key generation unit when a temporary recording instruction signal for temporarily recording the video data is supplied from the input unit. Stored in the buffer,
The encryption key generation unit stores the generated encryption key in the volatile memory,
Thereafter, when the recording processing instruction signal for saving the temporarily recorded video data stored in the buffer is supplied from the input unit, the recording processing unit transfers the temporary recorded video data from the buffer to the storage unit. Move and
When the front Symbol temporary recorded video data is stored in the storage unit, the encryption key used to encrypt the video data said stored is moved from the volatile memory to the non-volatile memory, according to claim 7 Data storage device. The recording processing unit deletes the desired video data from the storage unit upon receiving from the input unit a recorded video deletion instruction signal for deleting the desired video data from the video data stored in the storage unit. And
Encryption key used to encrypt the deletion was the desired image data is deleted from the nonvolatile memory, data storage device according to any one of claims 3,4,5,8. The recording processing unit, when receiving a temporary recording video deletion instruction signal for deleting the temporary recording video data from the input unit, deletes the temporary recording video data from the buffer,
Encryption key used to encrypt the deletion was the temporary recorded video data is deleted from the volatile memory, the data storage device according to any one of claims 4, 5, 8.   The data storage device according to any one of claims 2 to 6 and 8 to 10, wherein the encryption key generation unit generates a different encryption key for each broadcast program and stores the generated encryption key in the volatile memory. Wherein at a timing when power supply to the volatile memory is interrupted, the volatile memory of the encryption key to the non-volatile memory movement is executed, the data of any one of claims 1 to 11 Storage device. A first step in which an encryption key generation unit generates an encryption key;
A second step in which the encryption key generation unit stores the encryption key generated in the first step in a volatile memory;
A third step in which the data processing unit encrypts data supplied from the outside using the encryption key generated in the first step;
When the data processing unit receives an instruction to store the data supplied from the outside, the data encrypted in the third step is stored in the storage unit, and the encryption key writing unit stores the data stored in the data. And a fourth step of moving an encryption key used for encryption from the volatile memory to a non-volatile memory provided separately from the storage unit .   14. The encryption key storage method according to claim 13, wherein the data supplied from the outside is video data of a broadcast program. In the third step, when the data processing unit receives a temporary recording instruction for temporarily recording the video data, the video data is encrypted using the encryption key generated in the first step. Including the steps of
When the data processing unit stores the encrypted video data in a buffer as temporarily recorded video data and receives a temporary recording save instruction to save the temporarily recorded video data stored in the buffer, the temporarily recorded video data together moved from the buffer to the storage unit, the encryption key writing unit, a fifth step of moving said non-volatile memory the encryption key used to encrypt the video data the mobile from the volatile memory The encryption key storage method according to claim 14, further comprising: In the third step, when the data processing unit accepts a temporary recording instruction for temporarily recording the video data, the video data is encrypted using the encryption key generated in the first step. Including the steps of
The encryption key storage method according to claim 14, further comprising a fifth step in which the data processing unit stores the encrypted video data in a buffer as temporarily recorded video data. A first step in which an encryption key generation unit generates an encryption key;
A second step in which the data processing unit encrypts data supplied from the outside using the encryption key generated in the first step;
When the data processing unit receives an instruction to store the data supplied from the outside in the storage unit, the data processing unit stores the data encrypted in the second step in the storage unit, and the encryption key writing unit A third step of storing an encryption key used for encryption of stored data in a non-volatile memory provided separately from the storage unit ;
When the data processing unit receives an instruction to temporarily store the data supplied from the outside in the buffer, the data processing unit stores the data encrypted in the second step in the buffer, and the encryption key writing unit And a fourth step of storing, in a volatile memory, an encryption key used for encrypting the stored data.   The encryption key storage method according to claim 17, wherein the data supplied from the outside is video data of a broadcast program. In the third step, when the data processing unit receives a recording instruction for recording the video data supplied from the outside, the video data is encrypted using the encryption key generated in the first step. Storing the encryption key used for encrypting the stored video data in the nonvolatile memory, and storing the encryption key in the nonvolatile memory.
In the fourth step, when receiving a temporary recording instruction for temporarily recording the video data supplied from the outside, the data processing unit uses the encryption key generated in the first step. The step of encrypting video data and storing it in the buffer as temporarily recorded video data , and storing the encryption key used for encrypting the stored temporarily recorded video data in the volatile memory. Including
When the data processing unit accepts a temporary recording save instruction to save the temporarily recorded video data stored in the buffer, the temporary recording video data is moved from the buffer to the storage unit, and the encryption key writing unit, The encryption key storage method according to claim 18, further comprising a fifth step of moving an encryption key used for encrypting the moved temporarily recorded video data from the volatile memory to the nonvolatile memory. When the data processing unit receives a recorded video deletion instruction to delete desired video data from the video data stored in the storage unit , the data processing unit deletes the desired video data from the storage unit and the encryption The encryption according to any one of claims 15, 16, and 19, further comprising a step in which a key writing unit deletes an encryption key used for encryption of the deleted desired video data from the nonvolatile memory. Key storage method. When the data processing unit receives a temporarily recorded video deletion instruction to delete the temporarily recorded video data, the step of deleting the temporarily recorded video data from the buffer;
The encryption key writing unit further includes a step of deleting, from the volatile memory, an encryption key used for encrypting the deleted temporarily recorded video data. The encryption key storage method described in the paragraph. The encryption key storage method according to any one of claims 14 to 16 and 18 to 21, wherein the first step is a step in which the encryption key generation unit generates a different encryption key for each broadcast program. . The encryption key writing unit executes an encryption key transfer from the volatile memory to the nonvolatile memory at a timing when power supply to the volatile memory is cut off. 22. The encryption key storage method according to any one of 21.

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