JP2002026902A - Receiver terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a receiver terminal that prevents the use of itself due to interpretation of information with respect to a conditional access(CA) and an illegal copy so as to ensure high security. SOLUTION: The receiver terminal is provided with a means that stores a control program to a nonvolatile memory 1, a means that records ID information identifying the terminal and a key for a conditional access to a nonvolatile memory 2, a means that records the ID information and the key also to the nonvolatile memory 1, a means that reads the ID information and the key recorded in the nonvolatile memories 1, 2 and compares the both when the control program is started, and stops the reception operation when the both differ as a result of the comparison and also with a means that applies encryption by different encryption methods to the keys recorded in the nonvolatile memories 1, 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving terminal device used for digital broadcasting or data communication using a satellite or a cable.

[0002]

2. Description of the Related Art In recent years, digital broadcasting and digital data distribution using satellites and cables have been performed, and receiving terminal devices for receiving these and decoding video and audio have been widely used. Video and audio and data transmitted to these receiving terminal devices are usually scrambled, and a conditional access (hereinafter referred to as CA) mechanism is used so that only the contracted receiving terminal device can descramble. Normally, this is realized by using an IC card or the like, and a program for decrypting the encrypted information and necessary encryption key information are stored in the IC card to enhance confidentiality. (Listed in ARIB standard STB-B1)

[0003]

However, when a relatively small-scale operator operates using a unique CA mechanism, it is necessary to provide an IC at a low cost in order to provide a receiving terminal device at low cost.
It is also required to incorporate a decoding calculation program for CA into the control program of the receiving terminal device without using a card.

[0004] Such a control program incorporating a CA decoding operation program is held in a non-volatile memory such as a flash ROM, while viewing contract information and key information relating to the CA, and ID information for identifying the apparatus are provided. And the like, which is different depending on the receiving terminal device, is separated from the control program and held in another nonvolatile memory such as an EEPROM. A control program incorporating a CA decoding operation program has a program size of at least about 1 Mbyte or more even if its contents are read out.
It is relatively difficult for a third party to decode the decryption mechanism related to the above. On the other hand, since the access method of the EEPROM is standardized (IIC bus method), a device for monitoring a bus line is generally provided, and the recording capacity is about several kilobytes. It is relatively easy to duplicate the EEPROM itself, which is a factor that causes unauthorized use.

An object of the present invention is to solve the above-mentioned problems, and to provide means for preventing the use of a receiving terminal by decrypting information related to CA and illegal copying.

[0006]

In order to achieve the above object, a receiving terminal device of the present invention stores a control program in a nonvolatile memory 1 and identifies the device in a nonvolatile memory 2.
A means for recording ID information and a key for conditional access, and a means for recording the ID information and key in the non-volatile memory 1 are also provided. When the control program is started, the non-volatile memory 1 and the non-volatile memory 2 A means for reading out the ID information and the key recorded in the device, and stopping the receiving operation when both are different as a result of comparison with the means for comparing the two.

[0007] Alternatively, in order to achieve the above object, a receiving terminal device of the present invention divides a key into n pieces, and further performs encryption on the n pieces of the divided keys; It has means for recording the key at n discrete addresses in the nonvolatile memory 2 and means for decrypting the encrypted and discrete key.

[0008] Alternatively, in order to achieve the above object, the receiving terminal device of the present invention uses a part of the ID information or a second identification code generated from the ID information to encrypt the information relating to the key or the CA. And a means for generating an address for recording the encrypted key or information related to the CA using a part of the ID information or a second identification code generated from the ID information.

[0009] Alternatively, in order to achieve the above object, in the receiving terminal device of the present invention, the key recorded in the non-volatile memory 1 is encrypted by a second encryption method different from the key recorded in the non-volatile memory 1. And a means for recording together with dummy data for disturbing a predetermined location in the nonvolatile memory 1.

[0010] Alternatively, in order to achieve the above object, the receiving terminal device of the present invention includes an LED or a screen display means, and when the two are different, a means for notifying the LED or the screen display of an abnormality.

According to the present invention, a third memory such as an EEPROM is used.
Even if the information related to the CA recorded in the non-volatile memory, which is relatively easy to read and write by the user, is falsified or copied illegally and attached to another receiving terminal device, the control program is By verifying the coincidence with the individual information relating to the CA held in the recorded nonvolatile memory, unauthorized use can be prevented.

According to the invention, even if the non-volatile memory is read by a third party, it is difficult to specify the position of the address where information related to CA is recorded, and the key itself is encrypted. Therefore, the decryption is difficult and the security can be improved. Alternatively, according to the above invention, alteration or unauthorized use of information related to CA is detected, and a warning can be given to the user by notifying the LED or screen of the state.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a receiving terminal device according to claim 1, which is an embodiment of the present invention. In FIG. 1, transmission data input to a tuner 1 is extracted as a TS (Transport Stream), and a TS decoder 2 divides and decodes multiplexed video, audio, data, and the like into respective packets. The transmission data is usually scrambled, and the descrambler 3 descrambles the data.

Video and audio packets are input to the AV decoder 4 and decoded from the MPEG format, input to the NTSC encoder 5 and converted into a format that can be viewed on a television monitor. Meanwhile C
The PU 5 controls all operations of the receiving terminal device, and a control program for controlling all operations is stored in the flash memory 8. The EEPROM 9 holds parameters necessary for the operation of the control program, which should be stored even after the power is turned off.

Therefore, the contents of the EEPROM 9 have initial parameters written at the time of shipment, but can be rewritten at any time by the operation of the control program.
The RAM 7 is used as a work area for the operation of the program. The user input receiving unit 10
Receives signals such as operation buttons added to the remote control or the device, which are input means by the user,
The control program performs a predetermined operation according to a user input.

FIG. 2 is a flowchart showing the operation of the maintenance program which is a part of the control program of the receiving terminal device according to the present invention, and only the portions relating to the present invention are described. What is a maintenance program?
Instead of being used as a receiving terminal device by a normal user, a producer performs a diagnosis of the device or sets parameters in an initial state before shipment to the device in order to produce the receiving terminal device. .

A maintenance program is started by an instruction from a user's input means. The input means of the user at this time is a special input means which is not disclosed to the general user. ID information and CA for identifying the receiving terminal device in S201
Key information related to is input from outside. As an external input means, for example, a general-purpose I / F such as a personal computer is used, and the personal computer inputs ID information and key information relating to CA.

The CPU 6 temporarily stores the input ID information and key information in the RAM 7, and encrypts the key in S202.
In S203, the ID information and the encrypted key are stored in the EEPROM 9
To record. Next, in S204, the ID information and the encrypted key are recorded in a predetermined area of the flash memory 8 which is different from the control program.

On the other hand, FIG. 3 is a flowchart showing the operation of the receiving program which is a part of the control program of the receiving terminal device according to the present invention, and only the parts relating to the present invention are described. The receiving program is a program that is normally activated when used by a user. When the receiving program starts, first, in S301, the ID is read from the EEPROM 9
Read the information and the encrypted key information. Next, in step S302, the ID information and the encrypted key information are similarly read from the flash memory 8. Next, the ID read from both in S303
Compare and collate information. If the result matches,
In S305, the encrypted keys read from both are decrypted and compared and collated.

As a result, if they match, it is determined to be normal,
The receiving process is started in S307. On the other hand, if the result of determination in S304 or S306 is that they do not match, it is determined that either the EEPROM 9 or the flash memory 8 has been tampered with, and S3
At 08, the receiving process is stopped, appropriate abnormal processing is performed at S309, and the receiving program ends. The ID information and the key information are different for each receiving terminal device. According to the embodiment, for example, the EEPROM 9 of the first receiving terminal device is illegally copied and the EEPROM 9 copied to the second receiving terminal device is copied.
Even if the PROM is mounted, the ID information and the key information do not match as a result of the comparison with the flash memory, so that the second receiving terminal device cannot perform the receiving process, thereby preventing unauthorized use. In the above example, the keys recorded in both memories are encrypted. However, for example, even if encryption is not performed, the above effect is effective.

Next, a configuration example in the case of encrypting the key of the receiving terminal device according to the second embodiment of the present invention will be described. FIG. 4 is a diagram showing a configuration example when the key is encrypted in S202 of FIG.

The key 401 is composed of an N-bit data string, which is divided into n pieces as indicated by 402, and each of the divided data strings is subjected to a predetermined encryption. Create n. The encryption method is performed using, for example, a predetermined primary key built in the control program.
The divided encryption keys 403 are sequentially written to discrete EEPROM addresses defined in advance by the control program. 404 is an image of the contents of the written EEPROM. In this example, the encryption key 1 is sequentially stored in ascending order of the EEPROM address.
The storage order of ~ n may be random. The above claim 3
In the embodiment of the invention described above, ID information is used to make a method of encrypting a key and an address for recording an encryption key different for each receiving terminal device.

For example, all or part of the ID information 405 or a data string such as a check code generated from the ID information is used as a primary key, and an encryption key 403 and an encryption key 4 are used.
Calculate the address where 03 is stored. Reference numeral 406 denotes an image of the content of the EEPROM in which the encryption key has been written according to this embodiment. For example, the EEPR of the first receiving terminal device
The OM image and the EEPROM image of the second receiving terminal device are different from each other as indicated by reference numerals 404 and 406, so that the disturbing effect is further enhanced, decoding becomes difficult, and decoding of information related to CA can be prevented.

Further, according to the third embodiment, it is effective even when the key itself for performing encryption is not unique and common to the receiving terminal devices. For example, the CA obtained using the key is effective. By using it when encrypting contract information or the like related to, higher security can be ensured.

FIG. 5 is a schematic diagram showing the contents of a flash memory according to a fourth embodiment of the present invention. The control program of the receiving terminal device is recorded in the flash memory in advance. When the ID information and the encrypted key are written to the flash memory in step S204 of FIG. 2, dummy data of a predetermined size is also written together as shown in FIG.

The dummy data is realized by generating a random number by a control program. The contents of the flash memory written in this way are as indicated by 501, and even if the contents are read out by a third party, it is difficult to specify the key information from among them.

Further, by performing a second encryption different from the first encryption applied to the key recorded in the EEPROM,
Even if the contents of the EEPROM and the contents of the flash memory are read, it is difficult to compare the two and identify the key. The second cipher is, for example, changing the primary key from the first cipher, or changing the operation method. Further, the dummy data differs for each device by, for example, generating a random number based on time information obtained from the value of a timer built in the CPU 5.

According to this embodiment, the contents of the flash memory are different between the receiving terminal device A and the receiving terminal device B as indicated by 501 and 502. The flash memories of a plurality of devices are read, and the key information is specified by comparing the two. It is difficult to do so and it is possible to prevent decryption of the key.

FIG. 6 is a schematic diagram of a receiving terminal device according to a fifth embodiment of the present invention. In FIG. 3, if the information of the EEPROM and the flash memory are not matched as a result of the comparison. An example of the abnormal processing S309 will be described.

The receiving terminal device shown in FIG. 6 is equipped with a remote controller 604 as user input means, and has a display panel 603 and a warning LED 602 on a front panel. Further, a television monitor 601 is connected to view a video.

FIG. 7 shows a flowchart of the abnormal processing of the receiving terminal shown in FIG.

As a result of comparing the information in the EEPROM with the information in the flash memory, if a mismatch is detected, the control program proceeds to S7.
01 disables remote control input and disables user operation. Further, in step S702, the LED 602 indicating a warning is turned on, and in step S703, an error code for identifying the above state is displayed on the display panel 603. Further, a warning message is displayed on the screen of the S704 television monitor 601.

According to the above embodiment, unauthorized use can be prohibited and a warning can be issued to the user. In addition, when the apparatus is collected, it is easy to specify an abnormal location.

[0034]

According to the present invention, information about CA recorded in a nonvolatile memory such as an EEPROM which is relatively easy to read and write by a third party is falsified or illegally copied. Even if it is attached to another receiving terminal device, it is possible to prevent the unauthorized use by verifying the matching with the individual information relating to the CA stored in the nonvolatile memory in which the control program is recorded, Can be.

Further, according to the present invention, by a third party,
Even if the nonvolatile memory is read, it is difficult to identify the position of the address where the information related to the CA is recorded, and the key itself is also encrypted, so it is difficult to decipher and enhance the security. be able to. Further or according to the above invention, falsification of information related to CA,
By detecting unauthorized use and notifying the LED or screen of the state, a warning can be given to the user, and the abnormality of the apparatus can be easily specified.

[Brief description of the drawings]

FIG. 1 is a block diagram of a receiving terminal device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of the receiving terminal device according to the embodiment of the present invention;

FIG. 3 is a flowchart illustrating an operation of the receiving terminal device according to the embodiment of the present invention;

FIG. 4 is a diagram showing a configuration example when a key is encrypted according to an embodiment of the present invention;

FIG. 5 is a diagram showing a configuration example when a key is encrypted according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of a receiving terminal device according to an embodiment of the present invention.

FIG. 7 is a flowchart showing the operation of the receiving terminal device according to one embodiment of the present invention;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 tuner 2 TS decoder 3 descrambler 4 AV decoder 5 NTSC encoder 6 CPU 7 RAM 8 flash memory 9 EEPROM 10 user input receiving unit 401 key data string 402 divided key data string 403 encrypted key 404 EEPROM Data string 405 Data string of ID information 406 Data string of EEPROM 501 Contents of flash memory of receiving terminal device A 502 Contents of flash memory of receiving terminal device B 601 TV monitor 602 LED 603 Display plate 604 Remote control

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C064 BA01 BC17 BC22 BC23 BC27 CC06 5J104 AA07 KA02 KA04 NA02 NA07 NA27 NA36 NA37

Claims (5)

[Claims] 1. A receiving terminal device which holds a control program in a nonvolatile memory 1; means for recording ID information for identifying the device in a nonvolatile memory 2 and a key for conditional access; Means for recording information and a key, and when the control program is started, the ID recorded in the nonvolatile memory 1 and the nonvolatile memory 2
A receiving terminal device comprising: means for reading out information and a key, and stopping the receiving operation when the two are different as a result of comparison with the means for comparing the two. Means for dividing the key into n pieces, and further encrypting the n pieces of the divided keys, and dividing the n pieces of the encrypted keys into n discrete addresses of the nonvolatile memory 2. And a means for decoding the encrypted and discrete keys. 3. The key or the CA using a part of the ID information or a second identification code generated from the ID information.
Means for encrypting information relating to the information and means for generating an address for recording the encrypted key or information relating to the CA using a part of the ID information or a second identification code generated from the ID information. 3. The receiving terminal device according to claim 2, comprising: 4. A key to be recorded in the nonvolatile memory 1 is encrypted by a second encryption method different from the key to be recorded in the nonvolatile memory 1 so as to disturb a predetermined place in the nonvolatile memory 1. A receiving terminal device comprising: means for recording together with dummy data; and means for decrypting a key encrypted by the second encryption method. 5. The receiving terminal device according to claim 1, wherein
A receiving terminal device comprising: an LED or a screen display means; and a means for notifying an abnormality to the LED or the screen display when the two are different.