JP6031360B2 - Access control program, transmission device, reception device, and information leakage source identification device - Google Patents

Description

  The present invention relates to an access control program, a transmission device, a reception device, and an information leakage source identification device for identifying a leakage source of secret information related to a limited reception function of digital broadcasting.

In the current digital broadcasting, the copyright can be obtained by restricting the broadcast program (hereinafter referred to as “content”) only to the subscriber's receiving device, allowing the content to be received only by a legitimate receiving device, or performing copy restrictions. The function of performing protection is realized using CAS (Conditional Access System) which is an access control method.
Specifically, a function related to access control (for example, decryption of a key for decrypting encrypted content; hereinafter referred to as a CAS function) is mounted on an IC card (CAS card) that is a tamper-resistant module. The access restriction is performed by installing it as a CAS program in the receiving apparatus in software format.

However, this CAS function may break security due to outflow of a key (device key or the like) held inside the receiving apparatus, analysis of an algorithm, or the like. In other words, when the confidential information of the CAS function is leaked, it is possible to manufacture an unauthorized copy receiving apparatus using the confidential information.
In this way, when secret information such as a key in the CAS function is leaked, safety for protecting content in pay TV viewing, content copying, etc. is not secured, and it becomes difficult to continue operation of the broadcast service itself. End up.

  Therefore, in order to solve this problem, the functions related to access control to be mounted on the IC card are stored in the receiving device as a CAS program, and if the CAS function secret information is leaked, the CAS function is set via broadcast waves or communication. A method of updating is disclosed (see Patent Documents 1 and 2).

For example, in the technique disclosed in Patent Document 1, the transmission apparatus uses an ECAS-RMP (ECM: Entitlement Control Message, RMP: Rights Management and Protection), which is common information related to content right protection, to transmit an encrypted CAS program. Transmit to the receiving device. Further, the transmission apparatus transmits a key for decrypting the encrypted CAS program to the reception apparatus by EMM-RMP (EMM: Entitlement Management Message), which is individual information related to content right protection.
On the other hand, the receiving apparatus downloads and decrypts the encrypted CAS program distributed by ECM-RMP using the key distributed by EMM-RMP, thereby accumulating and updating the CAS program.

In the method disclosed in Patent Document 2, the transmission apparatus transmits a CAS program encrypted with a scramble key using a data carousel, encrypts the scramble key with a transmission path protection key, and transmits it to the reception apparatus using ECM-RMP. To do. The transmission device transmits the encrypted transmission path protection key to the reception device by EMM-RMP.
On the other hand, the receiving apparatus decrypts the encrypted scramble key distributed by ECM-RMP with the transmission path protection key distributed by EMM-RMP. Then, the receiving apparatus accumulates and updates the CAS program by decrypting the CAS program transmitted in the data carousel with the scramble key.
As a result, the methods described in Patent Documents 1 and 2 can update the CAS function in the receiving apparatus.

JP 2009-267605 A JP 2012-23547 A

  As described above, the conventional methods described in Patent Documents 1 and 2 update the CAS function even when the confidential information of the CAS function is leaked from the receiving device and an illegal duplicate receiving device is manufactured. Thus, the use of the content can be stopped in the unauthorized copy receiving device.

However, in the conventional method, the CAS function is updated all at once for receiving apparatuses that can receive digital broadcasting without specifying the leakage source of the secret information. For this reason, there is a possibility that a manufacturer that has illegally manufactured a duplicate receiving apparatus first will manufacture a duplicate receiving apparatus that duplicates a new CAS function by using secret information that is illegally obtained from the same receiving apparatus again.
That is, in the conventional method, the manufacture of an illegal copy receiving apparatus and the update of the CAS function are repeated, and there is a problem that the content is not properly protected.

In addition, when the unauthorized copy receiving device is a complete copy of the CAS function of the legitimate receiving device, the CAS function is updated without changing from the legitimate receiving device.
That is, the conventional method has a problem that content may not be properly protected simply by updating the CAS function.

  The present invention has been made in view of such a problem, and an access control program and a transmission apparatus capable of specifying a reception apparatus in which secret information is leaked and copied illegally in units of devices (device keys) It is an object of the present invention to provide a receiving device and an information leakage source specifying device.

  In order to solve the above-described problem, an access control program according to claim 1 is an access control program for limited reception of content incorporated in a digital broadcast receiving apparatus for each device of the receiving apparatus, and is encrypted. In order to decrypt the scramble key obtained by encrypting the content using related information related to the scramble key, the computer of the reception device functions as an individual information processing unit, a common information processing unit, and a decryption stop delay unit. It is characterized by making it.

In such a configuration, the access control program decrypts the individual information, which is information related to the key encrypted by the master key unique to the receiving device, transmitted from the transmitting device by the individual information processing means, using the master key. Get the work key included in the information.
Further, the access control program decrypts the common information, which is related information of the key encrypted by the work key, transmitted from the transmitting device by the common information processing means, with the work key decrypted by the individual information processing means, The scramble key included in the common information is acquired.
With this scramble key, the receiving apparatus can descramble (decrypt) the scrambled (encrypted) content.

Then, the access control program, as the delay parameter of the access control program that is different for each predetermined device of the receiving device, when the common information includes information that instructs the decoding stop delay means to stop the decoding of the scramble key Then, the delay time set in advance in the program is counted, and after the delay time has elapsed, the common information processing means is instructed to stop decoding the scramble key.
Here, the device of the receiving apparatus refers to a predetermined unit such as the manufacturer, model, and manufacturing lot of the receiving apparatus.

As a result, in a receiving device that operates with the access control program installed, when a scramble key decryption stop instruction is given by common information, after a different delay time has elapsed for each device of the receiving device set in the program The decryption of the scramble key is stopped, and as a result, the decryption of the content is stopped.
In this way, when an access control program with a different delay time until decoding stop for each device is incorporated in the receiving device, the access control function is duplicated from the receiving device and a duplicate receiving device is generated due to information leakage By including information instructing to stop decoding in the common information, the delay time differs for each device, and the device of the receiving apparatus that is the source of leakage can be specified.

  Further, the transmission device according to claim 2 uses the related information related to the content and the key that encrypted the content, the access control program for limited reception of the content, and the key that encrypted the access control program. A transmission device for digital broadcasting that transmits related related information to a receiving device, the first individual information generating means, the first common information generating means, the content scramble means, the second individual information generating means, The second common information generating means, the program scramble means, and the multiplexing means are provided.

  In such a configuration, the transmitting apparatus encrypts the first work key with the master key specific to the receiving apparatus by the first individual information generating unit, and the first individual information specific to the receiving apparatus including the encrypted first work key is obtained. Generate. Then, the transmission device encrypts the first scramble key with the first work key by the first common information generation means, and generates first common information common to the reception device including the encrypted first scramble key. Then, the transmission device encrypts the content with the first scramble key by the content scramble unit, and generates an encrypted content.

In addition, the transmission device encrypts the second work key with the device key for each device by the second individual information generation unit for each predetermined device of the reception device, and receives the encrypted second work key. Second individual information for each device of the apparatus is generated. Then, the transmitting device encrypts the second scramble key with the second work key by the second common information generating means, and generates second common information common to the receiving device including the encrypted second scramble key.
Then, the transmission apparatus encrypts an access control program in which a delay time different in advance for each device of the reception apparatus is incorporated as a delay parameter by the program scramble means, and generates an encrypted access control program.

Then, the transmitting device multiplexes the first individual information, the first common information, the encrypted content, the second individual information, the second common information, and the encrypted access control program by the multiplexing unit, Generate a broadcast signal.
As a result, the transmission apparatus can incorporate an access control program having an access control function in which the delay time from the instruction to stop decoding until the decoding stops differs for each device of the reception apparatus.

  The receiving device according to claim 3, wherein the content is encrypted content, the first common information common to the receiving device including the first scramble key encrypted the content, and the first scramble key. The first individual information of each receiving device including the first work key encrypted, the encrypted access control program that encrypts the access control program for limited reception of the content, and the access control program The second common information common to the receiving device including the second scramble key and the second individual information for each device of the receiving device including the second work key obtained by encrypting the second scramble key are multiplexed. A digital broadcast receiving apparatus that receives a broadcast signal from a transmitting apparatus, wherein the separating means, the second individual information processing means, and the second common information processing means , A program descrambling means, and an access control means, wherein the access control means has a first individual information processing means, a first common information processing means, and an operation of an access control program acquired by the program descrambling means, The configuration functions as decoding stop delay means.

In such a configuration, the receiving apparatus separates the multiplexed broadcast signal by the separating unit.
Then, the reception apparatus decrypts the second individual information separated by the separation means by the second individual information processing means with a device key that is a predetermined device unit key of the reception apparatus, and obtains a second work key To do. Further, the receiving device decrypts the second common information separated by the separating means by the second common information processing means with the second work key decrypted by the second individual information processing means, and obtains a second scramble key. .

Then, the receiving apparatus decrypts the encrypted access control program separated by the separating means by the program descrambling means with the second scramble key decrypted by the second common information processing means, and acquires the access control program. Then, the receiving device operates the access control program by the access control means.
Then, the receiving apparatus decrypts the first individual information separated by the separating means by the first individual information processing means with a master key that is a key unique to the receiving apparatus, and obtains a first work key. Further, the receiving device decrypts the first common information separated by the separating means by the first common information processing means with the first work key decrypted by the first individual information processing means, and acquires the first scramble key. .

Then, when the first common information includes information instructing to stop the decoding of the first scramble key by the decoding stop delay means, the receiving device counts a delay time set in advance as a delay parameter, and the delay After the elapse of time, the first common information processing means is instructed to stop decoding the first scramble key.
As a result, when the receiving apparatus is instructed to stop the decoding of the scramble key for decoding the content, an access control function for stopping the decoding is incorporated after the delay time predetermined for each device has elapsed.

  In addition, the information leakage source specifying device according to claim 4 is a reception that incorporates an access control program in which a delay time from when an instruction to stop decoding of a scramble key is instructed to when decoding is actually stopped differs for each device of the receiving device. An information leakage source identifying device that identifies whether a duplicate reception device copied from a device is copied due to information leakage from any of the devices, and includes a pseudo broadcast signal generation unit, an access control function type A pseudo broadcast signal generating means, an individual information generating means, a common information generating means, a content scrambling means, and a multiplexing means. The access control function type determining means is a storage means. The decoding stop detection unit, the delay time measurement unit, and the type determination unit are provided.

In such a configuration, the information leakage source specifying device encrypts the work key with the master key specific to the receiving device and generates the individual information specific to the receiving device including the encrypted work key by the individual information generating unit. The information leakage source specifying device encrypts the scramble key with the work key by the common information generating means, generates common information common to the receiving device including the encrypted scramble key, and at a timing instructed from the outside. The decryption stop information for instructing the stop of decryption by the scramble key is added to the common information.
Further, the information leakage source specifying device encrypts the content with the scramble key by the content scramble means, and generates the encrypted content.
Then, the information leakage source identifying device multiplexes the individual information, the common information, and the encrypted content by the multiplexing unit to generate a pseudo broadcast signal.
As a result, the information leakage source identifying device generates a pseudo broadcast signal including the encrypted content and key-related information for decrypting the encrypted content, and also transmits the pseudo broadcast signal to the copy receiving device via the pseudo broadcast signal. It is possible to instruct to stop decrypting the content.

On the other hand, the information leakage source identification device analyzes the display signal of the copy receiving device by the decoding stop detection means, and detects the stop of the decoding. Then, the information leakage source identifying device measures the delay time from the time when the decoding stop information is added to the common information by the common information generating means to the time when the decoding stop detecting means detects the stop of decoding by the delay time measuring means. To do.
Then, the information leakage source specifying device determines, by the type determination unit, the device identification stored in the storage unit in advance corresponding to the delay time measured by the delay time measurement unit as the information leakage source device.
As described above, since the delay time until the decoding is stopped is different for each device of the receiving apparatus, the information leaking source identifying apparatus measures the delay time to generate information on which device is leaked and generated by the duplicate receiving apparatus. Can be identified.

The present invention has the following excellent effects.
According to the first aspect of the present invention, since a different time is set in advance for each device of the receiving apparatus as the delay time until the scramble key decoding is stopped, the instruction to stop the scramble key decoding is instructed. In this case, different access control can be realized for each device of the receiving apparatus. As a result, even when the access control function is duplicated due to information leakage of the receiving apparatus, the leakage source device can be specified by the difference in delay time until decoding stops.

  According to the second and third aspects of the present invention, an access control program in which the delay time until the scramble key decoding stops for each device of the receiving apparatus can be incorporated into the receiving apparatus for each device. Thereby, even when the access control function is duplicated due to information leakage of the receiving apparatus, the leakage source device can be specified.

  According to the fourth aspect of the present invention, it is possible to stop the decryption of the content (scramble key) with respect to the duplicate receiving device that duplicates the access control function of the receiving device, and further to reduce the delay time until the stop. By measuring the time, a device corresponding to the delay time can be specified.

It is explanatory drawing for demonstrating the outline | summary of this invention, Comprising: (a) is a figure for demonstrating a mode that a different access control program (CAS program) is delivered for every device key, (b) is copied illegally. It is a figure for demonstrating the structure which specifies the information leakage origin from the received receiver. It is a block diagram which shows the structure of the transmitter which concerns on embodiment of this invention. It is a block diagram which shows the functional block of the access control program which concerns on embodiment of this invention. It is a figure which shows an example of the data format of the common information containing decoding stop information. It is a block diagram which shows the structure of the receiver which concerns on embodiment of this invention. It is a flowchart which shows the operation | movement which transmits the access control program (CAS program) of the transmitter which concerns on embodiment of this invention. It is a flowchart which shows the operation | movement which transmits the content of the transmitter which concerns on embodiment of this invention. It is a flowchart which shows the operation | movement which receives the access control program (CAS program) of the receiver which concerns on embodiment of this invention. It is a flowchart which shows the operation | movement which receives the content of the receiver which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the access control function (CAS function) of the access control program which concerns on embodiment of this invention. It is a block diagram which shows the structure of the information leakage origin specific apparatus which concerns on embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
[Outline of the present invention]
First, the outline of the present invention will be described with reference to FIG.
According to the present invention, an access control program (hereinafter referred to as a CAS program) for executing a function related to access control (hereinafter referred to as a CAS function) is created by a different program for each device of the receiving apparatus, and the illegally copied copy When a receiving apparatus is found, it is characterized by detecting from which device the duplicate receiving apparatus has been copied.
That is, in the present invention, as shown in FIG. 1A, the transmission apparatus 1 has CAS programs (CAS-PA, CAS-P A, PA) having different CAS functions for each device of the reception apparatus 2 (for example, for each manufacturer of the reception apparatus). CAS-P B, CAS-PC,...) Are encrypted on a device (device key) basis and transmitted to the receiving device 2 (2 ₁ , 2 ₂ , 2 ₃ ,...).

On the other hand, the receiving device 2 includes a device key assigned in advance for each device such as a receiving device manufacturer, and decrypts the CAS program addressed to itself in the device (device key) unit.
As a result, in the receiving apparatus 2, different CAS functions (CAS function A, CAS function B, CAS function C,...) Function for each device.
Here, in addition to a general CAS function, the CAS program has a function of stopping decoding of content by a broadcast signal. Further, the CAS program is a function that is different for each device (device key) of the receiving device 2, and it is assumed that the time from when an instruction to stop the decryption of the content to when the decryption is actually stopped differs.
As a result, when the receiving apparatus 2 is instructed to stop the decryption of the content, the decryption of the content is stopped at a different time depending on the CAS function for each device.

Here, when an illegally copied copy receiving device 2B is found, in the present invention, as shown in FIG. 1 (b), the information leakage source specifying device 3 makes a secret from which receiving device 2 having the CAS function. It is detected whether the information is leaked and the copy receiver 2B has been copied.
That is, the information leakage source specifying device 3 generates a pseudo-decoding stop of the content as a broadcast stream (broadcast signal), and instructs the decoding stop until the copy receiving device 2B actually stops decoding (that is, Measure the time until video / audio is interrupted.
Since the time until the actual decryption is stopped after this decryption stop instruction is different for each CAS function (device), which CAS function the information leakage source identifying device 3 has leaked from which receiving device 2 has the secret information leaked Can be specified.
Hereinafter, the transmitting device 1, the receiving device 2, and the information leakage source specifying device 3 according to the embodiment of the present invention will be described in detail.

[Configuration of transmitter]
First, the configuration of the transmission apparatus 1 will be described with reference to FIG. 2 (refer to FIG. 1 as appropriate).
The transmission device 1 transmits content (broadcast program) to the reception device 2 via broadcast waves. The transmission device 1 has a function of transmitting and updating a CAS program having a function related to access control to content via a broadcast wave.

  Here, the transmission apparatus 1 includes a storage unit 10, a content scramble unit 11, a first common information generation unit 12, a first individual information generation unit 13, a program scramble unit 14, and a second common information generation unit 15. And second individual information generating means 16 and multiplexing means 17.

The storage means 10 stores a key for scrambling / descrambling the content and the CAS program, a key for generating related information related thereto, and a CAS program P distributed to the receiving device 2. For example, the storage means 10 is composed of a storage medium such as a hard disk.
The scramble key Ks1, the work key Kw1 and the master key Km are keys for generating a key for limited reception of the content C and related information related thereto.

Specifically, the scramble key Ks1 is a key for scrambling the content C. The scramble key Ks1 is updated about once every few seconds. Here, it is assumed that the scramble key Ks1 is updated when a new scramble key Ks1 is appropriately input from the outside.
The scramble key Ks1 is used by the content scramble means 11 when the content C is scrambled.

  The work key Kw1 is a key for encrypting the scramble key Ks1. The work key Kw1 has a longer update time than the scramble key Ks1, and is updated in about one month, for example. Here, it is assumed that a new work key Kw1 is appropriately input from the outside and updated. The work key Kw1 is a key for encrypting the first common information that sets the scramble key Ks1 as key-related information common to the receiving device 2, and is used by the first common information generation means 12.

The master key Km is a key for encrypting the work key Kw1. The master key Km is a fixed key that is assigned to each receiving device 2 in advance that is different for each receiving device 2.
The master key Km is a key for encrypting the first individual information for setting the work key Kw1 as individual key related information for each receiving device 2, and is used by the first individual information generating means 13.

The scramble key Ks2, the work key Kw2 and the device key Kd are keys for generating a key for cryptographically transmitting the CAS program P and related information related thereto.
Specifically, the scramble key Ks2 is a key for scrambling the CAS program P. This scramble key Ks2 is updated about once every few seconds. Here, it is assumed that the scramble key Ks2 is updated by appropriately inputting a new scramble key Ks2 from the outside.

  The work key Kw2 is a key for encrypting the scramble key Ks2. The work key Kw2 has a longer update time than the scramble key Ks2, and is updated in about one month, for example. Here, it is assumed that a new work key Kw2 is appropriately input from the outside and updated. The work key Kw2 is a key for encrypting the second common information for setting the scramble key Ks2 as key-related information common to each device of the receiving device 2 (for example, each manufacturer of the receiving device). Used by the information generating means 15. Note that devices are distinguished in advance by unique identifiers (device identification).

The device key Kd is a key for encrypting the work key Kw2. The device key Kd is a key that is different for each device of the receiving apparatus 2 and is a fixed key that is assigned to the receiving apparatus 2 in advance in units of devices. The device unit is a predetermined unit for authenticating the receiving apparatus 2 and is, for example, for each manufacturer of the receiving apparatus, for each model, for each lot, or the like. Here, the device key Kd is stored in the storage unit 10 in association with the device identification.
The device key Kd is a key for encrypting the second individual information for setting the work key Kw2 as individual key related information for each device of the receiving device 2, and is used by the second individual information generating means 16.

  The CAS program P is a program for operating the CAS function in the receiving device 2. Specifically, the CAS program P extracts the scramble key Ks1 from the broadcast stream (broadcast signal) based on the related information (first common information, first individual information) of the scramble key Ks1 transmitted from the transmission device 1. To do. The CAS program P is a program implemented in units of devices (device identification [device key]) of the receiving device 2 and is stored in advance in the storage unit 10 in association with device identification.

Here, the CAS program P is different from the CAS program P for each device when an instruction (decryption stop information) for stopping the extraction of the scramble key Ks1 corresponding to the content C is notified via the broadcast signal. It has a function of stopping extraction of the scramble key Ks1 after elapse of a predetermined time.
The CAS program P may be configured as software that operates on an OS (Operating System), or may be configured by circuit information that operates on a programmable device such as an FPGA (Field Programmable Gate Array).
Detailed functional blocks of the CAS program P will be described later with reference to FIG.

The content scramble means 11 scrambles (encrypts) the input content (video, audio, data, etc.) C with the scramble key Ks1.
For the encryption with the scramble key Ks1, a common common key encryption algorithm may be used. For example, the encryption is performed by the MULTI2 encryption. The content scramble unit 11 outputs the scrambled content (encrypted content SC) to the multiplexing unit 17.

The first common information generating unit 12 encrypts the scramble key Ks1 used in the content scramble unit 11 with the work key Kw1, and generates common information (first common information) including the encrypted scramble key Ks1. A common common key encryption algorithm may be used for encryption using the work key Kw1.
Here, the first common information is information common to all receiving apparatuses 2. This first common information can be generated as a message having an ECM (Entitlement Control Message) structure defined by the limited reception method (CAS method) of STD-B25 of the Japan Radio Industry Association (ARIB). Here, the first common information generating unit 12 outputs the first common information (ECM-CAS) generated as ECM to the multiplexing unit 17.

The first individual information generating unit 13 encrypts the work key Kw1 used in the first common information generating unit 12 with the master key Km1, and generates individual information (first individual information) including the encrypted work key Kw1. It is. A general common key encryption algorithm may be used for encryption using the master key Km1.
Here, the first individual information is individual information for each receiving device 2. The first individual information can be generated as a message having an EMM (Entitlement Management Message) structure defined by the limited reception method (CAS method) of ARIB STD-B25. Here, the first individual information generating unit 13 outputs the first individual information (EMM-CAS) generated as an EMM to the multiplexing unit 17.

The program scramble means 14 scrambles (encrypts) the CAS program P with the scramble key Ks2. For the encryption with the scramble key Ks2, a common common key encryption algorithm may be used. The program scramble means 14 adds an identifier for identifying the CAS program P when generating the encrypted program SP scrambled from the CAS program P.
Further, the program scramble unit 14 sequentially reads out and scrambles the CAS program P which is different for each device of the receiving device 2 from the storage unit 10.
The program scramble means 14 outputs the scrambled program (encrypted program SP) to the multiplexing means 17.
Note that the program scramble means 14 may scramble the CAS program P in units of predetermined blocks and output it to the multiplexing means 17 in the form of a data carousel.

The second common information generating means 15 encrypts the scramble key Ks2 used in the program scramble means 14 with the work key Kw2, and generates common information (second common information) including the encrypted scramble key Ks2. A common common key encryption algorithm may be used for encryption using the work key Kw2.
Here, the second common information is information common to all receiving apparatuses 2. This second common information can be generated as a message having an ECM structure defined by the content protection method (RMP method) of ARIB STD-B25. Here, the second common information generation unit 15 outputs the second common information (ECM-RMP) generated as an ECM to the multiplexing unit 17.

The second individual information generating unit 16 encrypts the work key Kw2 used in the second common information generating unit 15 with the device key Kd, and generates individual information (second individual information) including the encrypted work key Kw2. It is. A common common key encryption algorithm may be used for encryption using the device key Kd.
Here, the second individual information is individual information for each device of the receiving device 2 (such as the manufacturer of the receiving device 2). The second individual information can be generated as a message having an EMM structure defined by the content protection scheme (RMP scheme) of ARIB STD-B25. The second individual information generating means 16 encrypts the work key Kw2 with the device key Kd corresponding to the same device identification as the CAS program P scrambled by the program scramble means 14.
Here, the second individual information generating unit 16 outputs the second individual information (EMM-RMP) generated as an EMM to the multiplexing unit 17.

  The multiplexing unit 17 is generated by the encrypted content SC generated by the content scramble unit 11, the first common information (ECM-CAS) generated by the first common information generation unit 12, and the first individual information generation unit 13. First individual information (EMM-CAS), encrypted program SP generated by the program scramble means 14, second common information (ECM-RMP) generated by the second common information generation means 15, and second individual information generation The second individual information (EMM-RMP) generated by the means 16 is multiplexed at the input stage to generate a multiplexed signal.

Here, it is assumed that the multiplexing means 17 multiplexes each input information into a TS (transport stream) format (MPEG-2 TS) defined by MPEG-2 Systems.
Although not shown here, the multiplexing means 17 appropriately multiplexes a PSI (Program Specific Information) / SI (Service Information) information table as program arrangement information in addition to these pieces of information. Needless to say. Further, when the transmission apparatus 1 wants to operate by designating the CAS program P, the CAS program P added to the encrypted program SP by the program scramble means 14 and transmitted to the reception apparatus 2 as program designation information in PSI / SI. The identifier may be added.

  By configuring the transmission apparatus 1 in this way, the transmission apparatus 1 is configured such that the time from when the instruction to stop the decoding of the content C is actually stopped until the decoding is actually stopped differs for each device of the reception apparatus 2. In addition, the CAS program P can be updated for each device of the receiving device 2.

[Structure of CAS program]
Next, the configuration of the CAS program (access control program) distributed by the transmission apparatus 1 will be described with reference to FIG. 3 (refer to FIG. 2 as appropriate).
As shown as functional blocks in FIG. 3, the CAS program P is a program for causing the computer of the receiving device 2 to function as the first individual information processing means 21, the first common information processing means 22, and the decoding stop delay means 23. It is.

  The first individual information processing means (individual information processing means) 21 inputs the first individual information (EMM-CAS) multiplexed in the broadcast stream and the master key Km, and uses the master key Km as the first individual information. The work key Kw1 is obtained by decryption. The first individual information processing means 21 outputs the decrypted work key Kw1 to the first common information processing means 22.

The first common information processing means (common information processing means) 22 inputs the first common information (ECM-CAS) multiplexed in the broadcast stream and the work key Kw1 decrypted by the first individual information processing means 21. The first common information is decrypted with the work key Kw1 to obtain the scramble key Ks1. The first common information processing means 22 outputs the decrypted scramble key Ks1 as an output result of the CAS program P.
However, when the first common information includes the decoding stop information, the first common information processing unit 22 outputs a notification indicating that the decoding stop information has been detected (decoding stop detection notification) to the decoding stop delay unit 23. . The first common information processing means 22 stops the output of the scramble key Ks1 after inputting the decryption stop instruction from the decryption stop delay means 23.

Here, the first common information (ECM-CAS) has an ECM structure as shown in FIG. In FIG. 4, information not directly related to the present invention is omitted.
As shown in FIG. 4, the scramble key is encrypted and stored in the fixed part of the ECM body following the ECM section header. Here, among the scramble keys that are updated as appropriate, two (Odd / Even) present and next scramble keys are shown.
As shown in FIG. 4, decoding stop information is stored in the variable part of the ECM main body as necessary. When decoding stop information is set in this variable part, the first common information processing means 22 outputs a decoding stop detection notification to the decoding stop delay means 23.
This decoding stop information is, for example, a predetermined unique identifier indicating that the information is decoding stop information.

The decoding stop delay unit 23 outputs a decoding stop instruction after a delay time set in advance as a delay parameter at the stage when the decoding stop detection notification is input from the first common information processing unit 22. The decoding stop delay means 23 measures the delay time by a timer (timer means) not shown. The delay parameter (delay time) is a different time for each device key assigned to the receiving apparatus 2 embedded in the CAS program P in advance.
Thereby, the CAS program P stops the output of the scramble key Ks1 after the delay time embedded therein has elapsed when the decryption stop information is notified by the first common information after being distributed to the receiving device 2. .

[Receiver configuration]
Next, the configuration of the receiving device 2 will be described with reference to FIG. 5 (refer to FIG. 1 as appropriate).
The receiving device 2 receives content (broadcast program) from the transmitting device 1 via broadcast waves. The receiving device 2 has a function of receiving and updating a CAS program having a function related to access control to content via a broadcast wave.

  Here, the receiving apparatus 2 includes an access control unit 20 including a first individual information processing unit 21, a first common information processing unit 22, and a decoding stop delay unit 23, a separation unit 24, a storage unit 25, a second An individual information processing unit 26, a second common information processing unit 27, a program descrambling unit 28, and a content descrambling unit 29 are provided.

The access control means 20 controls access to the content transmitted from the transmission device 1. The access control means 20 implements the CAS function by loading the CAS program P transmitted from the transmission apparatus 1 into the nonvolatile memory in the reception apparatus 2 and executing the program.
That is, the access control means 20 includes the first individual information processing means 21, the first common information processing means 22, and the decoding stop delay means 23, like the CAS program P described in FIG. . Since the individual configuration is the same as that of the CAS program P described with reference to FIG.

The first individual information (EMM-CAS) input to the first individual information processing means 21 is information separated from the broadcast stream by the separation means 24. The master key Km input to the first individual information processing unit 21 is a key unique to the receiving device 2 stored in advance in the storage unit 25.
The first common information (ECM-CAS) input to the first common information processing means 22 is information separated from the broadcast stream by the separation means 24. Further, the scramble key Ks1 output from the first common information processing unit 22 is output to the content descrambling unit 29.

  The separation unit 24 separates the broadcast stream (multiplexed signal; MPEG-2 TS) transmitted from the transmission device 1. The separating means 24 includes an encrypted content SC, first individual information (EMM-CAS) and first common information (ECM-CAS) including related information for limited reception, a CAS program, from MPEG-2 TS. The second individual information (EMM-RMP) and the second common information (ECM-RMP) including related information for encryption transmission and the encrypted CAS program SP are separated.

The storage unit 25 stores a key for decrypting related information for limited reception and related information for encrypted transmission of a CAS program. For example, the storage means 25 is composed of a storage medium such as a semiconductor memory.
Here, the storage unit 25 is a master key Km that is a key for decrypting related information for limited reception, and a key for decrypting related information for encrypted transmission of a CAS program, and includes a unique identifier ( The device key Kd specified by (device identification) is stored in advance.
The master key Km is a fixed key that is assigned to each receiving device 2 in advance, which is different for each receiving device 2. The device key Kd is a key that is different for each device of the reception apparatus 2 and is a fixed key that is assigned to the reception apparatus 2 in advance in units of devices (device identification).

  The second individual information processing means 26 decrypts the second individual information (EMM-RMP) separated by the separation means 24 with the device key Kd stored in advance in the storage means 25, and acquires the work key Kw2. It is. The second individual information processing means 26 outputs the decrypted work key Kw2 to the second common information processing means 27.

  The second common information processing means 27 decrypts the second common information (ECM-RMP) separated by the separation means 24 with the work key Kw2 decrypted by the second individual information processing means 26, and obtains the scramble key Ks2. To do. The second common information processing means 27 outputs the decrypted scramble key Ks2 to the program descrambling means 28.

The program descramble means 28 descrambles (decrypts) the encrypted CAS program SP separated and extracted by the separation means 24 with the scramble key Ks2 decrypted by the second common information processing means 27.
The program descrambling means 28 loads the descrambled CAS program P into a non-volatile memory (not shown) in the receiving apparatus 2 and operates it.

  More specifically, after the program descrambling means 28 stores the CAS program P in the storage means 25, the access control means 20 uses the PSI / SI to send program designation information including the identifier of the CAS program P. When notified, it is loaded into a nonvolatile memory and executed.

The content descrambling means 29 descrambles (decrypts) the encrypted content SC separated and extracted by the separating means 24 with the scramble key Ks1 output from the first common information processing means 22 of the access control means 20 (CAS program P). )
The content descrambling means 29 outputs the descrambled content C to the outside. As a result, the content is reproduced by a display device (not shown) connected to the outside.

  By configuring the receiving device 2 in this way, the receiving device 2 receives the time from when the CAS program P distributed in device units is instructed to stop the decoding of the content C until the actual decoding is stopped. It is possible to control the apparatus 2 so as to have different times for each device.

[Operations of transmitter and receiver]
Next, operations of the transmission device 1 and the reception device 2 will be described with reference to FIGS.

[Operation of transmitting apparatus: CAS program transmission]
First, the CAS program transmission operation of the transmission device 1 will be described with reference to FIG.
First, the transmitting apparatus 1 encrypts the work key Kw2 with the device key Kd corresponding to the same device (device identification) as the CAS program P to be scrambled by the second individual information generating means 16, and uses the encrypted work key Kw2 The included individual information (second individual information) is generated (step S1).
Then, the transmitting apparatus 1 encrypts the scramble key Ks2 for scrambling the CAS program P with the work key Kw2 by the second common information generating means 15, and common information including the encrypted scramble key Ks2 (second common information). ) Is generated (step S2).

Further, the transmission apparatus 1 reads the device-unit CAS program P from the storage means 10 by the program scramble means 14 and scrambles it with the scramble key Ks2 (step S3).
Then, the transmission apparatus 1 uses the multiplexing unit 17 to generate the second individual information (EMM-RMP) generated in step S1, the second common information (ECM-RMP) generated in step S2, and the step S3. The scrambled encryption program SP is multiplexed to generate a multiplexed signal (broadcast stream) (step S4).

Here, the CAS program transmission operation has been described as a series of operations. However, the second individual information and the second common information are generated at the timing when the work key Kw2 and the scramble key Ks2 are updated, and are multiplexed by the multiplexing unit 17. Multiplexed.
The transmission apparatus 1 performs the above operation for each CAS program P for each device. As a result, the transmission apparatus 1 can transmit different CAS programs P for each device to the reception apparatus 2.

[Transmission Device Operation: Content Transmission]
Next, the content transmission operation of the transmission apparatus 1 will be described with reference to FIG.
First, the transmitting apparatus 1 encrypts the work key Kw1 with the master key Km for each receiving apparatus 2 by the first individual information generating unit 13, and the individual information including the encrypted work key Kw1 (first individual information) Is generated (step S11).
Then, the transmitting device 1 encrypts the scramble key Ks1 for scrambling the content C with the work key Kw1 by the first common information generation means 12, and common information (first common information) including the encrypted scramble key Ks1. Is generated (step S12).

Further, the transmitter 1 scrambles the content C with the scramble key Ks1 by the content scramble means 11 (step S13).
Then, the transmitter 1 uses the multiplexing unit 17 to generate the first individual information (EMM-CAS) generated in step S11, the first common information (ECM-CAS) generated in step S12, and the step S13. The scrambled encrypted content SC is multiplexed to generate a multiplexed signal (broadcast stream) (step S14).
Here, the content transmission operation has been described as a series of operations. However, the first individual information and the first common information are generated at the timing when the work key Kw1 and the scramble key Ks1 are updated and multiplexed by the multiplexing unit 17. It becomes.

  The operation of the transmission apparatus 1 has been described above. In the CAS program transmission operation in FIG. 6 and the content transmission operation in FIG. 7, the operation of the multiplexing unit 17 to generate a multiplexed signal (steps S4 and S14) They do not work individually. That is, the multiplexing means 17 sequentially multiplexes each information at the timing when the information to be multiplexed is generated.

[Receiver Operation: CAS Program Reception]
Next, the CAS program receiving operation of the receiving apparatus 2 will be described with reference to FIG.
First, the receiving device 2 separates the information multiplexed in the broadcast stream (broadcast signal; multiplexed signal) transmitted from the transmitting device 1 by the separating means 24 (step S21).
When the second individual information (EMM-RMP) is included in the information separated in step S21, the receiving device 2 stores the second individual information in the storage unit 25 in advance by the second individual information processing unit 26. The work key Kw2 is obtained by decrypting with the stored device key Kd (step S21).

  In addition, when the second common information (ECM-RMP) is included in the information separated in step S21, the receiving device 2 decodes the second common information in step S21 by the second common information processing unit 27. The work key Kw2 is decrypted to obtain the scramble key Ks2 (step S22).

Then, when the encrypted CAS program SP is included in the information separated in step S21, the receiving device 2 converts the encrypted CAS program SP into the scramble key Ks2 decrypted in step S22 by the program descrambling means 28. Is descrambled (step S23).
Through the above operation, the CAS program P that is different for each device is loaded in the receiving apparatus 2.

[Receiver operation: content reception]
Next, the content reception operation of the reception device 2 will be described with reference to FIG.
First, the receiving device 2 separates the information multiplexed in the broadcast stream (broadcast signal; multiplexed signal) transmitted from the transmitting device 1 by the separating means 24 (step S31).
Then, the receiving device 2 performs access control (CAS function operation) on the content by the access control means (CAS program) 20 (step S32).

Here, the operation of step S32 in the access control means 20 will be described in detail with reference to FIG.
As illustrated in FIG. 10, when the first individual information (EMM-CAS) is included in the information separated in step S <b> 31 of FIG. 9, the reception device 2 includes the first individual information processing unit of the access control unit 20. 21, the first individual information is decrypted with the master key Km stored in advance in the storage means 25 to obtain the work key Kw1 (step S321).

In addition, when the first common information (ECM-CAS) is included in the information separated in step S31 in FIG. 9, the reception device 2 uses the first common information processing unit 22 of the access control unit 20 to perform the first process. The common information is decrypted with the work key Kw1 decrypted in step S321 to obtain the scramble key Ks1 (step S322).
If the first common information includes decoding stop information (Yes in step S323), the first common information processing means 22 notifies the decoding stop delay means 23 to that effect (decoding stop detection notification). Then, the receiving device 2 starts measuring time until the decoding is stopped by the decoding stop delay unit 23 (step S324), and proceeds to step S325.
On the other hand, when the decoding stop information is not included in the first common information (No in step S323), the reception device 2 advances the operation to step S325.

Then, the reception device 2 decodes the first common information processing unit 22 when the time (delay time) of the delay parameter set in advance by the decoding stop delay unit 23 has elapsed (Yes in step S325). By notifying the stop instruction, the first common information processing means 22 stops the output of the scramble key Ks1 (step S326).
On the other hand, if the measured time has not yet passed the delay parameter time (delay time) (No in step S325), the first common information processing means 22 outputs the scramble key Ks1 (step S327).
Thereby, the access control means 20 (CAS program P) stops the output of the scramble key Ks1 after a delay time predetermined for each device has elapsed after receiving the decryption stop information.
Returning to FIG. 9, the content receiving operation of the receiving device 2 will be described.

By the operation described with reference to FIG. 10, it is controlled in step S32 whether or not the scramble key Ks1 is output from the access control means 20 (CAS program P).
When the scramble key Ks1 is output from the access control means 20 (CAS program P) (Yes in step S33), the receiving apparatus 2 uses the content descramble means 29 to encrypt the encrypted content SC separated by the separation means 24. Is descrambled with the scramble key Ks1 (step S34).

On the other hand, when the scramble key Ks1 is not output from the access control means 20 (CAS program P) (No in step S33), the receiving device 2 does not perform descrambling in the content descrambling means 29.
As a result, when the decoding stop is instructed in the broadcast stream (broadcast signal), the receiving device 2 stops the decoding of the content after the delay parameter time (delay time) embedded in the CAS program P elapses.

[Information leakage source identification device]
Next, the information leakage source specifying device 3 will be described with reference to FIG.
The information leakage source specifying device 3 is a copy of the CAS function (which device) that is copied by the duplicate receiving device 2B that has illegally obtained the secret information (key information, algorithm, etc.) of the CAS function from the receiving device 2 and copied it. Is specified.
Here, the information leakage source specifying device 3 includes a pseudo broadcast signal generation unit 31 and a CAS function type determination unit 32.

  Among the functions of the transmission apparatus 1 (see FIG. 2), the pseudo broadcast signal generation unit 31 uses a content, a key for scrambling the content, and related information as a broadcast stream (pseudo broadcast stream [pseudo broadcast signal]). It simulates the function to be generated. Furthermore, the pseudo broadcast signal generation means 31 has a function of adding decoding stop information for stopping descrambling of content to a broadcast stream.

Here, the pseudo broadcast signal generation unit 31 includes a content scramble unit 310, a common information generation unit 311, an individual information generation unit 312, and a multiplexing unit 313.
The content scrambling means 310, the individual information generating means 312 and the multiplexing means 313 are the same as the content scrambling means 11, the first individual information generating means 13 and the multiplexing means 17 of the transmitting apparatus 1 described in FIG. Therefore, the description is omitted. However, the output destination of the pseudo broadcast stream (pseudo broadcast signal) multiplexed by the multiplexing unit 313 is the copy receiving device 2B.

The common information generating unit 311 encrypts the scramble key Ks1 used in the content scramble unit 310 with the work key Kw1, and generates common information including the encrypted scramble key Ks1. It has the same function as the common information generating means 12.
Further, the common information generation unit 311 has a function of adding the decoding stop information to the common information when the decoding stop information is input from the outside. That is, when the decoding stop information is input, the common information generating unit 311 generates the common information as a message having an ECM structure and adds the decoding stop information to the variable part as described in FIG.
Also, the common information generating unit 311 generates common information with the decoding stop information added, and outputs the common information with the decoding stop information to the CAS function type determination unit 32 at the timing when the common information is output to the multiplexing unit 313. Notify that it has been sent to.

Note that the scramble key Ks1 and the work key Kw1 input to the pseudo broadcast signal generation means 31 do not need to be updated and a fixed key may be used.
Further, the master key Km input to the pseudo broadcast signal generation means 31 is sequentially input with the master key Km previously given to the regular receiving device 2. The master key Km is switched at a time interval longer than the maximum delay time of the delay parameter (delay time) embedded in the CAS program P in advance.

The CAS function type determination means (access control function type determination means) 32 analyzes the display signal (video / audio signal) of the copy receiver 2B, and at the time from when the decoding is instructed to when the decoding is actually stopped. Based on this, the CAS function of the copy receiver 2B, that is, which device's CAS function has been copied is specified.
Here, the CAS function type determination unit 32 includes a storage unit 320, a decoding stop detection unit 321, a delay time measurement unit 322, and a type determination unit 323.

  The storage unit 320 stores a delay time D, which is a delay parameter incorporated in advance in the CAS program P of the regular receiving device 2, and a device identification K for identifying the device of the receiving device 2 in association with each other. Is. For example, the storage means 25 is composed of a storage medium such as a hard disk.

The decoding stop detection means 321 detects that the decoding has been stopped by determining whether or not the display signal (video / audio signal) of the copy receiver 2B has been cut off.
The determination of whether or not the display signal is interrupted can be performed by video-capturing the display signal and analyzing the image. For example, the decoding stop detection unit 321 performs video capture of the display signal at a predetermined frame interval, and determines that the display signal has been disconnected when the captured image has not changed for a predetermined time. Further, for example, the decoding stop detection unit 321 analyzes the pixel value of the captured frame image, and determines that the display signal is disconnected when the entire frame image is darkened (blacked out).
When the decoding stop detection unit 321 detects that decoding is stopped, the decoding stop detection unit 321 notifies the delay time measurement unit 322 to that effect.

  In this case, it is assumed that the copy receiving device 2B is a device having a configuration in which the display device is separated, such as a PC (personal computer), and the display signal that is directly output from the copy receiving device 2B by the decoding stop detection unit 321. It was decided to input. However, when the copy receiving device 2B is configured to include a display device such as a television receiver, the display screen of the copy receiving device 2B is taken again by an imaging device such as a camera (not shown), and decoding is stopped. The detection means 321 may input a display signal from the imaging device.

The delay time measuring unit 322 measures a delay time from when the common information with the decoding stop information added is generated until descrambling (decoding) of the content is stopped in the copy receiver 2B.
Here, the delay time measuring unit 322 starts measuring time when notified by the common information generating unit 311 that the common information with decoding stop information has been transmitted, and detects the decoding stop from the decoding stop detecting unit 321. The time until notification of this is measured as a delay time.
The delay time measuring unit 322 outputs the measured delay time to the type determining unit 323.

The type determining unit 323 specifies the type of the CAS function in which the duplicate receiving apparatus 2B is operating based on the delay time measured by the delay time measuring unit 322.
Here, the type determination unit 323 reads the device type K stored in the storage unit 320 corresponding to the delay time measured by the delay time measurement unit 322, and outputs the device type K to the outside as a determination result. The type determination unit 323 determines whether or not the delay time, which is an actual measurement value measured by the delay time measurement unit 322, matches the delay time D stored in the storage unit 320 within a predetermined error range. The corresponding device type K is read out.

In this way, by configuring the information leakage source identification device 3, the information leakage source identification device 3 instructs the copy reception device 2B to stop decoding with the common information (ECM-CAS), and the decoding is actually performed. Based on the delay time until the stop, it is possible to identify which device the confidential information of the duplicate reception apparatus 2B has been duplicated due to the leakage of the CAS function.
The information leakage source specifying device 3 is not limited to this configuration.
For example, the pseudo broadcast signal generation unit 31 and the CAS function type determination unit 32 may be configured as separate devices (pseudo broadcast signal generation device, CAS function type determination device).

As described above, the access control program, the transmission device, the reception device, and the information leakage source identification device that can identify the reception device in which the secret information is leaked and illegally copied according to the present invention in units of devices (device keys) are described. did.
By identifying the information leakage source device in this way, for example, updating an access control program to which a new function is added only for a legitimate receiving device (a receiving device of a device that is not leaking information), etc. Can be operated.
As described above, the present invention can specify the device of the receiving device that has been illegally copied, and thus has an effect as a deterrent against the illegal copying of the receiving device.

DESCRIPTION OF SYMBOLS 1 Transmission apparatus 10 Memory | storage means 11 Content scramble means 12 1st common information generation means 13 1st separate information generation means 14 Program scramble means 15 2nd common information generation means 16 2nd separate information generation means 17 Multiplexing means 2 Receiver 20 Access control means (access control program [CAS program])
21 1st individual information processing means (individual information processing means)
22 1st common information processing means (common information processing means)
23 Decoding stop delay means 24 Separation means 25 Storage means 26 Second individual information processing means 27 Second common information processing means 28 Program descrambling means 29 Content descrambling means 2B Duplicate receiving device 3 Information leakage source specifying device 31 Pseudo broadcast signal generation Means 310 Content scrambling means 311 Common information generating means 312 Individual information generating means 313 Multiplexing means 32 CAS function type determining means (access control function type determining means)
320 storage means 321 decoding stop detection means 322 delay time measurement means 323 type determination means

Claims (4)

An access control program for limited reception of content incorporated in a digital broadcast receiving device for each device of the receiving device, wherein the content is encrypted using related information related to an encrypted scramble key In order to decrypt the scramble key, a computer of the receiving device is
Individual information processing means for obtaining the work key by decrypting the individual information, which is the related information including the work key encrypted with the master key unique to the receiving apparatus, transmitted from the transmitting apparatus,
The common information which is the related information including the scramble key encrypted by the work key transmitted from the transmission device is decrypted with the work key decrypted by the individual information processing means, and the scramble key is obtained. Common information processing means,
When the common information includes information instructing to stop decoding of the scramble key, a delay time set in advance in the program as a delay parameter of an access control program that differs for each predetermined device of the receiving apparatus And after the delay time elapses, decryption stop delay means for instructing the common information processing means to stop decoding of the scramble key,
Access control program to function as The related information related to the content and the key that encrypted the content, the access control program for limited reception of the content, and the related information related to the key that encrypted the access control program are transmitted to the receiving device. A digital broadcast transmitter,
First individual information generating means for encrypting a first work key with a master key for each receiving apparatus and generating first individual information for each receiving apparatus including the encrypted first work key;
First common information generating means for encrypting a first scramble key with the first work key and generating first common information common to the receiving device including the encrypted first scramble key;
Content scramble means for encrypting the content with the first scramble key and generating encrypted content;
For each predetermined device of the receiving device, a second work key is encrypted with the device key for each device, and second individual information for each device of the receiving device including the encrypted second work key is generated. Individual information generating means;
A second common information generating means for encrypting a second scramble key with the second work key and generating second common information common to the receiving device including the encrypted second scramble key;
A program scramble means for encrypting the access control program according to claim 1 in which a delay time different in advance for each device of the receiving apparatus is incorporated as a delay parameter with the second scramble key, and generating an encrypted access control program;
The first individual information, the first common information, the encrypted content, the second individual information, the second common information, and the encrypted access control program are multiplexed to generate a broadcast signal. Multiplexing means;
A transmission device comprising: Reception including encrypted content obtained by encrypting content, first common information common to a receiving device including the first scramble key obtained by encrypting the content, and first work key obtained by encrypting the first scramble key. Common to the receiving device including the first individual information for each device, the encrypted access control program that encrypts the access control program for limited reception of the content, and the second scramble key that encrypts the access control program Digital broadcasting for receiving, from the transmission device, a broadcast signal obtained by multiplexing the second common information and the individual second individual information for each device of the reception device including the second work key obtained by encrypting the second scramble key. Receiving device,
Separating means for separating the multiplexed broadcast signal;
Decrypting the second individual information with a device key which is a predetermined device unit key of the receiving device, and obtaining the second work key;
Second common information processing means for decrypting the second common information with a second work key decrypted by the second individual information processing means and obtaining the second scramble key;
Program descrambling means for decrypting the encrypted access control program with the second scramble key decrypted by the second common information processing means and obtaining the access control program;
Access control means for operating the access control program acquired by the program descrambling means,
The access control means is operated by the access control program.
First individual information processing means for decrypting the first individual information with a master key which is a key of the receiving device and obtaining the first work key;
First common information processing means for obtaining the first scramble key by decrypting the first common information with the first work key decrypted by the first individual information processing means;
When the first common information includes information instructing to stop decoding of the first scramble key, a delay time set in advance as a delay parameter is counted, and after the delay time has elapsed, the first common information processing The receiving apparatus functions as a decryption stop delay means for instructing the means to stop the decryption of the first scramble key. A copy receiving apparatus copied from a receiving apparatus that incorporates an access control program in which a delay time from when an instruction to stop decoding of a scramble key is instructed to when decoding is actually stopped is different for each device of the receiving apparatus. An information leakage source identification device that identifies whether the information was copied due to information leakage from the device,
Pseudo broadcast signal generating means for generating a pseudo broadcast signal and transmitting it to the copy receiver;
An access control function type determination means for identifying an information leakage source device of the access control function of the copy receiver from the display signal obtained by decoding the pseudo broadcast signal by the copy receiver;
The pseudo broadcast signal generating means includes
Individual information generating means for encrypting a work key with a master key for each receiving device, and generating individual information for each receiving device including the encrypted work key;
Decryption stop information for encrypting the scramble key with the work key, generating common information common to the receiving device including the encrypted scramble key, and instructing to stop decryption with the scramble key at an externally instructed timing Common information generating means for adding to the common information;
Content scramble means for encrypting content with the scramble key and generating encrypted content;
A multiplexing means for multiplexing the individual information, the common information, and the encrypted content to generate a pseudo broadcast signal;
The access control function type determination means includes
Storage means for associating and storing device identification, which is information for identifying the device, and a delay time until the decoding stop information is acquired and decoding is stopped;
Decoding stop detection means for analyzing the display signal of the copy receiving device and detecting decoding stop;
A delay time measuring means for measuring a delay time from the time when the decoding stop information is added to the common information in the common information generating means to the time when the decoding stop detecting means detects the stop of decoding;
Type determination means for determining the device identification stored in the storage means as the information leakage source device corresponding to the delay time measured by the delay time measurement means,
An information leakage source identification device comprising:

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