JP3608933B2 - Confidential information change system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a secret information change system, a secret information change first device, a secret information change second device, and a medium.
[0002]
[Prior art]
Conventionally, a television program or the like sent by satellite broadcasting is received by a dedicated receiver (hereinafter simply referred to as an STB) and recorded by a VTR device connected to the STB or on a television. Watching is done.
[0003]
In this case, the broadcast video / audio data includes, for example, data that is prohibited from recording and conditional data that can be recorded only once. Therefore, in order to observe these conditions, it is assumed that the user side recognizes this condition correctly and uses a device that operates normally.
[0004]
Therefore, when transmitting AV data that can be recorded only once from the STB to, for example, a VTR device, first, an authentication operation for confirming whether or not the VTR device is a regular device as described above. Will be carried out.
[0005]
The configuration of conventional STB and VTR devices and the authentication operation will be briefly described below.
[0006]
Generally, a common secret function S used for performing the authentication operation is stored in advance in such STB and VTR devices.
[0007]
When there is a request for AV data transmission from the VTR device to the STB, as described above, first, the STB and the VTR device mutually use the secret function S, and the following challenge-response type: An operation called authentication is performed.
[0008]
That is, first, a request (authentication request) is issued from the VTR device to the STB. Upon receiving this, the STB issues a challenge x (response request) to the VTR device and waits for a response from the VTR device. Also, the STB generates S (x) from the above x using its own secret function S. It should be noted that the description of S (x) indicates that x is encrypted with the secret function S.
[0009]
On the other hand, the VTR device independently generates S (x) from the received challenge x using its own secret function S, and sends the S (x) to the STB.
[0010]
The STB compares the S (x) generated by itself with the S (x) sent from the VTR device. If they match, the STB determines that the VTR device is a legitimate device and starts transmitting AV data. To do. If they do not match, it is determined that the VTR device is an unauthorized device, and AV data is not transmitted.
[0011]
When a plurality of devices are connected to the STB, the secret functions possessed by the plurality of devices may be the same or may be unique to each. In the latter case, the STB has all the secret functions unique to these devices, and uses a secret function corresponding to the authentication counterpart device for authentication.
[0012]
[Problems to be solved by the invention]
However, in the authentication method as described above, an unauthorized person imitates the secret function S of a legitimate device as it is, manufactures and sells an unauthorized device that can perform the same authentication method as described above, and the unauthorized device is used. In this case, the authentication method cannot detect that the device is an unauthorized device. Therefore, if it is found that the secret function S is misused by an unauthorized person, the only way to prevent the use of the unauthorized device is to prevent the abused secret function S from being used. For this reason, there is a problem in that even a legitimate device that has a secret function S that is prohibited from being used in advance cannot be used.
[0013]
In consideration of such a conventional problem, the present invention provides a secret information change system, a secret information change first device, a secret information change second device, and the like, which can reduce harmful effects associated with the removal of unauthorized devices, The purpose is to provide a medium.
[0014]
[Means for Solving the Problems]
The first aspect of the present invention provides a first device having a plurality of pieces of first secret information to be used for authentication or predetermined processing,
Among the plurality of second secret information corresponding to the plurality of first secret information, all or a part of the second secret information is included, and the second secret information is used to communicate with the first device. A second device for performing the authentication or the processing corresponding to the predetermined processing,
The first or second secret information is changed based on an external instruction that tells the first or second secret information used by the first or second device to be changed. In the secret information changing system, one of the devices receiving the instruction from the outside instructs the other device to change the secret information based on the instruction.
[0015]
The present invention described in claim 2 is a first device having a plurality of pieces of first secret information to be used for authentication or predetermined processing,
Among the plurality of second secret information corresponding to the plurality of first secret information, all or a part of the second secret information is included, and the second secret information is used to communicate with the first device. A second device for performing the authentication or the processing corresponding to the predetermined processing,
When there is an external instruction to notify that the first or second secret information should be changed, the first or second device selects which of the secret information is to be changed, In the secret information changing system, one device that has received the instruction from the outside instructs the other device to change the secret information based on the instruction.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0021]
(First embodiment)
FIG. 1 is a configuration diagram showing the configuration of a secret information changing system according to an embodiment of the present invention. Hereinafter, the configuration of the secret information changing system and each device according to the present embodiment will be described with reference to FIG. State.
[0022]
As shown in the figure, an antenna 110 is means for receiving broadcast radio waves from a broadcast communication satellite, and a satellite broadcast receiver (hereinafter simply referred to as STB) 120 receives received broadcast radio waves as AV. It is a means for converting to data or the like. In addition to normal television programs broadcast by a broadcasting station (not shown), this broadcast radio wave includes broadcasting of change instruction information that indicates that the secret function currently in use should be changed to another secret function. ing. The broadcast of the change instruction information is performed based on an instruction from a management center (not shown) that manages the secret function. The management center broadcasts such change instruction information when it obtains information that a secret function has been stolen by an unauthorized person and determines that the confidentiality of the secret function is no longer maintained. The change instruction information is attached with unique ID information of the device that is using the stolen secret function. The secret function is used in the authentication work between the devices, and will be described later.
[0023]
The transmission line 160 is a bus line for transmission provided between the STB 120 and the VTR device 140.
[0024]
Next, the internal configuration of the STB 120 will be further described with reference to FIG.
[0025]
In other words, the receiving means 121 is a means that is directly connected to the antenna 110, demodulates the received data, cancels the broadcast scramble applied to the received data, and further separates the multiplexed received data. is there. The received data includes the change instruction information described above. The broadcast of the change instruction information may be multiplexed with radio waves of other program broadcasts as in the present embodiment, but may be broadcast alone.
[0026]
The change instruction information detecting unit 125 detects only the change instruction information with its own unique ID information from the signal output from the receiving unit 121, and indicates that the change instruction information has been detected. It is a means to output to 128. The secret function storage means 126 is means for storing eight secret functions S1 to S8 in advance. Also, it is assumed that identification numbers 1 to 8 corresponding to the secret functions S1 to S8 are given to the secret functions S1 to S8, respectively. The secret function history information storage means 127 is a means for storing the secret function that is prohibited from use and the identification number of the secret function currently in use. The secret function selecting means 128 is a means for obtaining an instruction from the change instruction information detecting means 125 and changing the secret function currently in use to another secret function in consideration of the contents of the secret function history information storage means 127. is there. That is, the secret function selection means 128 is a means for selecting one new secret function from the secret function storage means 126, reading the secret function together with its identification number, and sending them to the authentication means 123 as secret function designation information. . The secret function selection means 128 is a means for updating the contents of the secret function history information storage means 127.
[0027]
On the other hand, the encryption unit 122 encrypts the AV data output from the reception unit 121 in a compressed state using the encryption work key Kw provided in advance based on an instruction from the authentication unit 123, or The work key Kw is encrypted using the subkey Ksub generated by the authentication means 123. The sub key Ksub will be described later. Here, it is necessary to send the work key Kw encrypted as described above to the terminal device because the terminal device decrypts the transferred AV data and records it. This is because it is assumed.
[0028]
The authentication unit 123 is a unit that performs an authentication operation for confirming whether or not the VTR device is a legitimate device with the VTR device that has requested transfer of AV data based on the secret function designation information. The authentication means 123 is a means for sending the identification number information included in the secret function designation information to the VTR device 140 as the authentication partner when starting the authentication.
[0029]
The data transfer means 124 is IEEE 1394 known as a digital interface. The data transfer means 124 is divided into two types, isochronous transfer suitable for transferring data such as video and audio, which requires real-time guarantee, and asynchronous transfer suitable for transferring authentication data and commands which are not necessary. It is a means for performing transfer.
[0030]
Next, the internal configuration of the VTR device 140 will be further described with reference to FIG.
[0031]
As shown in the figure, the data transfer means 141 is a digital interface similar to the data transfer means 124.
[0032]
The secret function storage unit 145 is a unit that stores 16 secret functions S1 to S16 in advance. Further, it is assumed that the secret functions S1 to S16 are given identification numbers 1 to 16 corresponding to the secret functions S1 to S16, respectively. These secret functions S1 to S8 are the same as the secret function possessed by the secret function storage means 126 described above, including the identification number. The secret function designation information extracting unit 146 detects the identification number information from the transmitted signal, extracts the corresponding secret function from the secret function storage unit 145 based on the identification number information, and outputs the secret function to the authentication unit 142 It is.
[0033]
The authentication unit 142 is a unit that performs an authentication operation based on an instruction from the secret function designation information extraction unit 146. The authentication unit 142 is a unit that generates the same subkey Ksub as that generated by the authentication unit 123 and outputs it to the decryption unit 143. The decryption unit 143 decrypts the encrypted work key Kw obtained from the data transfer unit 141 with the subkey Ksub to restore the work key Kw, and decrypts the encrypted AV data with the work key Kw. Means. The recording / reproducing means 144 is means for recording the decrypted AV data and reproducing the recorded data. Here, the first device of the present invention corresponds to the VTR device 140, and the second device of the present invention corresponds to the STB 120. The plurality of first secret information of the present invention corresponds to secret functions S1 to S16. In the present embodiment, the plurality of second secret information corresponding to the plurality of first secret information of the present invention is the same as the plurality of first secret information. Also, some of the second secret information among the plurality of second secret information corresponding to the plurality of first secret information of the present invention corresponds to the secret functions S1 to S8.
[0034]
With the above configuration, the operation of the present embodiment will be described below with reference to FIGS. 1, 2A, and 2B.
[0035]
In the present embodiment, description will be made on the assumption that there are two secret functions that are already prohibited from being used. 2A and 2B are schematic diagrams showing the contents of the secret function history information storage means. In FIG. 2A, the identification numbers of the secret functions S1 and S2 whose use has already been prohibited are 1 and 2, and the prohibited temporal order is the order of the identification numbers 1 and 2. It is also shown that the identification number of the secret function S3 currently in use is 3.
[0036]
Step 101: That is, the management center that has obtained the information that the currently used secret function S3 has been stolen by an unauthorized person between the STB 120 and the VTR device 140 has attached the unique ID information of the STB 120. A predetermined broadcast station is instructed to broadcast the change instruction information.
[0037]
Step 102: The broadcast station broadcasts the change instruction information by multiplexing with the normal broadcast program currently being broadcast, and subsequently multiplexes the normal broadcast programs A, B and C after the normal broadcast program. To broadcast.
[0038]
Step 103: Broadcast data received by the antenna 110 of the STB 120 is subjected to the predetermined processing by the receiving means 121, demultiplexed, and output to the encrypting means 122 and the change instruction information detecting means 125.
[0039]
Step 104: The change instruction information detecting means 125 checks whether or not the signal output from the receiving means 121 includes change instruction information with its own unique ID information. Here, since the presence of the change instruction information with its own ID information is detected, this fact is output to the secret function selection means 128. The secret function selection means 128 that has obtained the above output from the change instruction information detection means 125 first reads the contents of the secret function history information storage means 127 (see FIG. 2A), and the secret whose secrecy cannot be secured. It is understood that the function identification number is 1 to 3. Next, the secret function S4 with the identification number 4 is selected from the remaining secret functions except the secret functions with the identification numbers 1 to 3 from the secret function storage means 126 (see FIG. 1), and these are read out. And output to the authentication means 123 as secret function designation information. With this secret function designation information, the authentication unit 123 updates the secret function S3 and its identification number 3 held in the internal memory 123a with the secret function S4 and its identification number 4. In the present embodiment, selection of a new secret function is performed in ascending order of identification numbers of the secret function storage means 126 as described above. Also, the secret function selection means 128 updates the contents of the secret function history information storage means 127 as shown in FIG. Here, FIG. 2B shows a situation in which the secret function with the identification number 3 is added as a use-prohibited function and the identification number of the secret function to be used is 4 when compared with FIG. 2A. FIG.
[0040]
Step 105: On the other hand, in the VTR device 140, in order to record the broadcast program A, the authentication unit 142 first makes a request to the STB 120 via the data transfer unit 141. The authentication in this embodiment is the same challenge / response type authentication as described above, except that the secret function used for authentication is changed according to an instruction from the outside.
[0041]
Step 106: That is, the data transfer means 124 of the STB 120 that has received the request from the VTR device 140 sends the contents to the authentication means 123. In response to this, the authentication unit 123 sends the challenge x to the VTR device 140, and simultaneously reads out the identification number 4 recorded in the internal memory 123a and sends it as identification number information. The challenge x is generated by generating a random number.
[0042]
Step 107: The secret function designation information extraction unit 146 of the VTR device 140 detects the identification number information from the signal transmitted to the data transfer unit 141, and reads information No. 4 as the identification number from the content. . Then, the secret function S4 corresponding to No. 4 is extracted from the secret function storage unit 145 and output to the authentication unit 142.
[0043]
Step 108: The authenticating means 142 generates S4 (x) from the challenge x using the secret function S4 sent in this way, and sends it to the STB 120 as a response. Further, the authentication unit 142 generates a sub key Ksub · x from the challenge x and sends it to the decryption unit 143.
[0044]
Step 109: The authentication means 123 of the STB 120 compares S4 (x) uniquely generated using the secret function S4 stored in the internal memory 123a with S4 (x) of the response from the VTR device 140. As a result of comparison, in this case, it is determined that they are the same, and authentication is established. Further, the authentication means 123 of the STB 120 generates a subkey Ksub · x from the challenge x as a result of the authentication being established in this way. This subkey is the same as described in step.
[0045]
Hereinafter, since the operation after the authentication is established (steps 110 to 111) is not a characteristic operation of the present embodiment, it will be briefly described.
[0046]
Step 110: The encryption unit 122 obtains authentication establishment information from the authentication unit 123, and encrypts only the broadcast program A from the signal output from the reception unit 121 with the work key Kw. The encryption unit 122 encrypts the work key Kw with the sub key Ksub · x. Then, the encrypted Kw (AV data of broadcast program A) and Ksub · x (Kw) are sent from the data transfer means 124 to the VTR device 140.
[0047]
Step 111: The decryption means 143 decrypts the transmitted Ksub · x (Kw) using the obtained subkey Ksub · x, and further uses the decrypted Kw to produce Kw (broadcast program A AV data) is decoded. The decrypted AV data of the broadcast program A is recorded by the recording / reproducing means 144.
[0048]
By the way, a case where there is a request similar to that described in step 105 from an unauthorized device (not shown) that has stolen the secret function S3 will be briefly described.
[0049]
That is, in this case, since the unauthorized device does not know the new secret function S4, the response to the challenge x from the STB 120 can only generate S3 (x). Therefore, the response from such a device does not coincide with the new S4 (x) prepared as a comparison reference by the STB 120, and authentication is not established. Therefore, the request data is not transferred to such an apparatus, and the subsequent processing is terminated. As a result, only unauthorized devices can be completely eliminated.
[0050]
The authentication operation when there is no change instruction from the management center is basically the same as steps 105 to 111 described above.
[0051]
Next, an operation different from the above when the management center obtains information that the secret function S4 has been stolen by an unauthorized person will be described.
[0052]
When the secret function that cannot be kept confidential and cannot be used increases to some extent, the management center tells the manufacturer of the STB device that the secret function storage means 126 is stored after the STB of the next lot is produced. Instruct to update the contents. In response to this instruction, the manufacturer, when producing the STB of the next lot, removes the secret functions S1 to S4 that have already become unusable from the 16 secret functions S1 to S16. A secret function is newly selected and stored in the secret function storage means 126 together with its identification number (see FIG. 3A). FIG. 3A is a schematic diagram showing the contents of the secret function storage means built in the STB produced as the next lot. FIG. 3B is a schematic diagram showing the contents of the secret function storage means built in the already produced STB. In this way, even if the contents of the secret function storage means built in the STB are updated, the update is only within the range of the secret functions stored in advance in the already produced VTR device. The problem that the VTR apparatus cannot be used does not occur. In this way, by updating the contents of the secret function storage means built in the STB at a predetermined timing, the STB can be placed under the management of the management center. That is, here, it is not assumed that the STB is an unauthorized device, but by placing the STB under the management of the management center in this way, for example, the usage prohibition is not performed without following the change instruction from the management center. It is possible to create an environment in which illegal STBs that continue to use secret functions are unlikely to occur.
[0053]
In the above embodiment, the case where the content of the secret function storage unit 126 is updated at the stage of manufacturing a new device is described. However, the present invention is not limited to this. May be transmitted by broadcast waves from a broadcasting station according to an instruction from the management center, and updating may be performed based on the broadcast waves. In this case, the receiving unit 121 and the change instruction information detecting unit 125 in FIG. 1 need to have the following functions in addition to the above functions. That is, first, update instruction information having secret function data is broadcast from a broadcasting station. Here, the case where the content of the update instruction information is equivalent to that shown in FIG. 3A and the content of the secret function storage means 126 is the same as that shown in FIG. The receiving means 121 receives this update instruction information, outputs it separately from other broadcast data. The change instruction information detecting unit 125 detects update instruction information from the output of the receiving unit 121, and extracts secret functions S5 to S12 and identification numbers 5 to 12 included in the update instruction information. Further, the contents of the secret function storage means 126 (see FIG. 3B) are updated with the extracted secret function and its identification number. As a result, the contents of the secret function storage means 126 are the contents shown in FIG. Other configurations are the same as those described in FIG.
[0054]
(Second Embodiment)
FIG. 4 is a block diagram showing the configuration of the secret information changing system in one embodiment of the present invention. Hereinafter, the configuration of the secret information changing system and each device of the present embodiment will be described with reference to FIG. State.
[0055]
In this embodiment, a secret information changing system composed of the STB 400 and the DVD player 420 will be described. The same components as those described with reference to FIG. Is omitted. Therefore, here, the difference from the above embodiment will be mainly described. The main differences between the present embodiment and the above embodiment are as follows.
(1) The change instruction information is recorded on the DVD.
(2) The content of the change instruction specifies the identification number of the secret function to be used.
(3) The DVD player 420 detects the change instruction information and selects a secret function.
(4) Therefore, the number of secret functions that the secret function storage means 424 in the DVD player has is less than the number of secret functions that the secret function storage means 404 in the STB has.
(5) It is assumed that data is read from the DVD by the DVD player 420 and viewed on the monitor 410 connected to the STB 400, and it is assumed that an illegal STB is excluded.
[0056]
As shown in FIG. 4, the STB 400 and the DVD player 420 are connected via a transmission line 160 by data transfer means 405 and 425. The data transfer means 405 and 425 are both composed of IEEE 1394 as in the above embodiment.
[0057]
As shown in the figure, the configuration of the DVD player 420 is the same as that of the STB 120 shown in FIG. 1 except for the following points such as newly provided with a drive 421 and a data decoding means 422.
[0058]
That is, the drive 421 is means for rotating the set DVD and reading the recording signal. The data decoding means 422 is means for decoding AV data from the signal read by the drive 421. The change instruction information detection unit 125 is a unit that detects change instruction information from a signal output from the drive 421. Unlike the secret function selection unit 128, the secret function extraction unit 424 is a unit that extracts a secret function from the secret function storage unit 423 based on the identification number specified by the change instruction information. Therefore, the secret function history information storage means 127 shown in FIG. 1 is not necessary here. The secret function storage means 423 is a means for storing secret functions S101 to S108 and their identification numbers 101 to 108 different from the secret functions described in FIG. Further, the authentication means 123 is different from FIG. 1 in that it includes a history memory 123b in addition to the internal memory 123a. The history memory 123b is means for recording a history of identification numbers of secret functions whose use is prohibited. Here, the first device of the present invention corresponds to the DVD player 420, and the second device of the present invention corresponds to the STB 400. The reproducing means of the present invention is means including a drive 421 and the like.
[0059]
On the other hand, the configuration of the STB 400 shown in FIG.
[0060]
That is, the secret function designation information extraction unit 406 detects the identification number information from the transmission signal from the DVD player 420, extracts the corresponding secret function from the secret function storage unit 404 based on the identification number information, and authenticates the authentication unit 401. It is a means to output to. The decrypting unit 402 decrypts the encrypted work key Kw using the subkey Ksub sent from the authenticating unit 401, and further decrypts the encrypted AV data using the decrypted work key Kw. Means for sending to the decoder 403. Here, the identification number information is basically the same as that described in the first embodiment. These means other than the decoder 403 are basically the same as the means having the same name among the means in the VTR apparatus 140 described in FIG. However, the secret function and its identification number stored in the secret function storage means 404 are means for storing secret functions S101 to S116 and their identification numbers 101 to 116 different from the secret function described in FIG.
[0061]
The decoder 403 is means for expanding the decoded AV data and outputting the expanded signal to the monitor 410 because it remains compressed. The antenna 110 and the receiving unit 121 are the same as those described in FIG. 1 except that the output of the receiving unit 121 is sent to the decoder 403.
[0062]
Next, the operation of the present embodiment will be described.
[0063]
Here, the management center that has obtained information that the secret function S101 currently used has been stolen by an unauthorized person, ₂ In addition to normal AV data, the DVD manufacturer is instructed to record change instruction information indicating that the secret function with the identification number 102 should be used, and the scene in which the DVD is manufactured is considered. And that new DVD ₂ Will be described.
[0064]
Step 201: The user plays a DVD to watch the desired movie. ₂ Is set in the DVD player 420, and a drive switch (not shown) is turned on. As a result, the drive 421 ₂ Is first rotated to check whether the change instruction information is recorded. If it is recorded, it is detected and output to the secret function extracting means 424.
Step 202: The secret function extracting means 424 examines the contents of the change instruction information. Here, since the content is to use the secret function of the identification number 102, the secret function S102 corresponding to the identification number 102 is extracted from the secret function storage means 423. The extracted secret function S102 and its identification number 102 are sent to the authentication means 123.
[0065]
Step 203: The authentication means 123 uses the secret function S102 sent from the secret function extraction means and its identification number 102 to determine the secret function S101 currently in use recorded in the internal memory 123a and its identification number 101. Update. Furthermore, 101 is additionally recorded in the history memory 123b as the identification number of the secret function prohibited from being used. Use of the history memory 123b will be described later.
[0066]
Step 204: The authentication operation performed by the authentication unit 123 authenticates whether the STB 400 is a legitimate device. The authentication operation performed between the authentication unit 123 and the authentication unit 401 is almost the same as the challenge / response type authentication described in steps 106 to 109.
[0067]
However, in the present embodiment, the DVD player 420 sends a challenge x to the STB 400, and the positions of the STB and its connection device are reversed from those in the first embodiment. At this time, the identification number 102 recorded in the internal memory 123a is read out and sent together with the challenge x as identification number information.
[0068]
The secret function designation information extraction unit 406 of the STB 400 performs the same operation as the secret function designation information extraction unit 146 in step 107, but here, the content of the identification number information indicates the identification number 102. Therefore, the secret function S102 corresponding to the secret function storage unit 404 is extracted and output to the authentication unit 401.
[0069]
Further, the generation of the response and the subkey Ksub · x in the authentication unit 401 is the same as the content of the above step 108.
[0070]
Further, the authentication success / failure determination and the generation of the sub key Ksub · x in the authentication means 123 of the DVD player 420 are the same as the contents of step 109 described above.
[0071]
Step 205: The AV data decrypted by the decrypting means 402 after the authentication is established is sent to the decoder 403, decompressed, and sent to the monitor 410. In this way, the user can watch the desired movie.
[0072]
As a result, as in the case of the above embodiment, only unauthorized devices can be excluded.
[0073]
Next, DVD ₂ Compared with the old DVD ₁ Briefly describe the case of watching.
[0074]
This DVD ₁ It is assumed that the change instruction information indicating that the secret function having the identification number 101 is to be used is recorded.
[0075]
In this case, the following operation is performed before the update of the internal memory 123a described in step 203.
[0076]
That is, the authentication unit 123 compares the contents of the history memory 123b with the updated contents before the update. Here, the identification number 101 has already been recorded as use prohibition in the history memory 123b. Accordingly, it is determined that the use that has already been prohibited is to be restored. In this case, the update is not performed and such change instruction information is ignored.
[0077]
As a result, once the new type DVD is played back, the secret function can be kept new even when the old type DVD is played back, so that unauthorized devices can be more reliably eliminated. .
[0078]
Also in this embodiment, the contents of the secret function storage means 423 built in the DVD player 420 are updated at a predetermined timing in the manufacturer as in the case described in the first embodiment. Yes.
[0079]
(Third embodiment)
FIG. 5 is a block diagram showing the configuration of the secret information changing system according to one embodiment of the present invention. Hereinafter, the configuration of the secret information changing system and each device according to the present embodiment will be described with reference to FIG. State.
[0080]
In the present embodiment, a VTR device 140 and a DVD player 420 similar to those described in the above embodiment are connected to the STB 500 via a transmission line 160. The STB 500 is configured to have both functions of the STB 120 and the STB 400 described in the above embodiment. Accordingly, the same components as those described above are denoted by the same reference numerals and description thereof is omitted.
[0081]
Here, the difference from the above embodiment will be mainly described. The main differences between the present embodiment and the above embodiment are as follows.
(1) The secret function used by the STB 500 is different depending on the type of connected device.
(2) The authentication means 501 of the STB 500 is configured so as to use both the position indicating the secret function to be used and the position instructed on the contrary depending on the relationship with the data transmission / reception partner. That is, the authentication means 501 when transferring AV data from the STB 500 to the VTR device 140 is in a position to instruct the VTR device 140 of a secret function to be used in the authentication operation. On the other hand, the authentication unit 501 in the case where the reproduction signal transferred from the DVD player 420 is displayed on the monitor 410 is in a position where the DVD player 420 instructs the secret function to be used in the authentication operation. These operations are the same as those described separately in the above embodiment, and are omitted here.
[0082]
Next, based on an instruction from the management center, a brief description will be given of a case in which there is change instruction information for a secret function used by the DVD player 420 from a broadcasting station. Note that the contents of this change instruction are contents that specify the identification number of the secret function to be used.
[0083]
This change information passes through the antenna 110 of the STB 500, enters the change instruction information detection means 125 via the reception means 121, and is the same as described above. The change instruction detection unit 125 determines whether or not the secret function that is the target of the change instruction corresponds to a function that the STB 500 itself can change independently. The secret function is determined not to be changed by the STB 500 itself, and the change instruction information is sent to the data transfer means 405 and transferred to the DVD player 420.
[0084]
In the DVD player 420 of this embodiment, a signal transmission line not shown in FIG. 4 is newly provided between the data transfer 425 and the change information detection means 125 shown in FIG. Information is sent to the change instruction information detection means 125. The subsequent operations are the same as when the change instruction information is output from the drive 421.
[0085]
Thus, also in this embodiment, the same effect as in the above case is exhibited.
[0086]
By the way, a program for causing a computer to execute the function of all or a part of each of the units described in any one of the above-described embodiments is stored on a medium such as a magnetic recording medium or an optical recording medium. It is also possible to create a recorded one and use it to perform the same operation as described above.
[0087]
In the above-described embodiment, the case has been described in which the change instruction information from the outside indicates the one to be used when changing the one currently in use. The identification number to be increased may be increased, in other words, the version number of the identification number to be used may be increased, and the inside of each device may have a configuration corresponding thereto. However, in such an ascending type configuration, for example, there is change instruction information for suddenly changing the identification number to 8 when the identification number currently in use is 1, in order to eliminate illegal instructions. However, this may be ignored and only the change to the identification number 2 may be performed.
[0088]
In the above-described embodiment, the case where the number of secret functions included in the STB and each device is different is described. However, the present invention is not limited to this. For example, the number may be the same for both.
[0089]
The first or second secret information of the present invention is a secret function used for authentication in the above embodiment, but is not limited to this. For example, a secret key or public key used for authentication, and other keys It may be a kind of key from which to generate
[0090]
In the above embodiment, the first or second secret information of the present invention is a secret function used for authentication. However, the present invention is not limited to this. For example, data to be transferred is encrypted regardless of authentication. It may be used to do so. In this case, there may be no authentication means.
[0091]
In the above embodiment, the challenge / response type authentication is used as the authentication method, and the instruction of the secret function to be used is performed at the same time as the challenge. However, the present invention is not limited to this. The authentication method may be used. Regardless of the authentication method, the device that has the initiative to change the secret information instructs the secret information to be used.
[0092]
In the above embodiment, the case where the first secret information and the second secret information of the present invention are the same has been described. However, the present invention is not limited to this.
[0093]
【The invention's effect】
As is apparent from the above description, the present invention has the advantage that the adverse effects associated with the elimination of unauthorized devices can be reduced as compared with the prior art.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a configuration of a secret information changing system according to an embodiment of the present invention.
FIGS. 2A and 2B are schematic diagrams showing the contents of secret function history information storage means in the embodiment;
FIG. 3A is a schematic diagram showing the contents of secret function storage means built in the STB produced as the next lot in the present embodiment.
(B): Schematic diagram showing the contents of the secret function storage means built in the already produced STB in the present embodiment
FIG. 4 is a configuration diagram showing a configuration of a secret information changing system according to a second embodiment of the present invention.
FIG. 5 is a configuration diagram showing a configuration of a secret information changing system according to a third embodiment of the present invention.
[Explanation of symbols]
110 Antenna
120 STB
140 VTR device
160 Transmission line
125 Change instruction information detection means
121 Receiving means
126 Secret function storage means
127 Secret function history information storage means
128 Secret function selection means
123 Authentication means
122 Encryption means

Claims (13)

A first device having in advance a plurality of first secret information to be used for authentication or predetermined processing;
Among the plurality of second secret information corresponding to the plurality of first secret information, all or a part of the second secret information is included, and the second secret information is used to communicate with the first device. A second device that performs the authentication or the processing corresponding to the predetermined processing,
The first or second secret information is changed based on an external instruction that tells the first or second secret information used by the first or second device to be changed. And
The secret information change system, wherein one of the devices that has received the instruction from the outside instructs the other device to change the secret information based on the instruction. A first device having in advance a plurality of first secret information to be used for authentication or predetermined processing;
Among the plurality of second secret information corresponding to the plurality of first secret information, all or a part of the second secret information is included, and the second secret information is used to communicate with the first device. A second device that performs the authentication or the processing corresponding to the predetermined processing,
When there is an external instruction to notify that the first or second secret information should be changed, the first or second device selects which of the secret information is to be changed;
The secret information change system, wherein one of the devices that has received the instruction from the outside instructs the other device to change the secret information based on the instruction. The second device has a part of the second secret information among the plurality of second secret information,
Based on an instruction from the outside that informs that the second secret information used by the second device should be changed, which second secret the second device has in the second secret information that the second device has. To select whether to change to information,
3. The secret information changing system according to claim 2, wherein the second device instructs the first device to change the first secret information based on the selection result. The number of second secret information included in the second device is the same as the number of first secret information included in the first device;
When there is an instruction from the outside notifying that the first or second secret information used by the first or second device should be changed, the first or second device has the secret The secret information in the information is selected to be changed, and the first or second device selects the second or first device based on the selection result with respect to the second or first device. The secret information changing system according to claim 2, wherein the secret information changing system instructs to change the first secret information. A management device for managing the first or second secret information used in the first or second device;
The external instruction is an instruction issued from the management apparatus, and the instruction is sent to the first or second apparatus via radio waves or a telephone line. 3. The secret information changing system according to 3 or 4. The first or second device comprises a reproducing means for reproducing a recording medium,
5. The secret information changing system according to claim 1, wherein the instruction from the outside is information recorded in the recording medium reproduced by the reproducing means. The instruction from the outside uses which secret information in the remaining secret information excluding the first or second secret information possessed by the first or second device that is no longer confidential. 2. The secret information changing system according to claim 1, wherein the secret information changing system is an instruction as to whether or not it should be. The second device has a part of the second secret information among the plurality of second secret information,
The management device adopts one of the plurality of first secret information from the remaining first secret information excluding the one whose confidentiality is no longer maintained, and uses them as a new second secret information It is determined to be information,
6. The secret information changing system according to claim 5, wherein the partial second secret information included in the second device is updated with the new second secret information based on the determination. . The second device has a part of the second secret information among the plurality of second secret information,
The management device adopts one of the plurality of first secret information from the remaining first secret information excluding the one whose confidentiality is no longer maintained, and uses them as a new second secret information Information is determined, and the determined new second secret information is transmitted to the second device,
6. The secret information changing system according to claim 5, wherein the second device updates the second secret information already possessed by the transmitted new second secret information. The second device has a part of the second secret information among the plurality of second secret information,
Adopting any one of the plurality of first secret information from the remaining first secret information excluding those whose confidentiality is no longer maintained, and making them new new secret information With a management device to determine,
7. The secret information changing system according to claim 6, wherein the partial second secret information included in the second device is updated with the new second secret information based on the determination. . The second device has a part of the second secret information among the plurality of second secret information,
Adopting any one of the plurality of first secret information from the remaining first secret information excluding those whose confidentiality is no longer maintained, and making them new new secret information A management device for determining and transmitting the determined new second secret information to the second device;
The secret information changing system according to claim 6, wherein the second device updates the second secret information already possessed by the transmitted new second secret information. 7. The secret information changing system according to claim 6, wherein when an instruction inconsistent with the instruction is recorded on the recording medium reproduced by the reproducing means, the instruction is ignored. The secret information is a secret function, a secret key, or a public key used for an authentication operation performed before the data transmission between the data transmitting device and the data receiving device. The secret information changing system according to 1 or 2.

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