JP2825053B2 - Pay broadcast transmission / reception system and pay broadcast receiving decoder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paid broadcast transmitting / receiving system and a paid broadcast receiving decoder, and more particularly to a paid / received transmitting / receiving system for transmitting and receiving pay broadcasts such as satellite broadcasting and cable television (CATV). Related to a decoder.

[0002] In pay broadcasting such as satellite broadcasting and CATV,
In order to prevent unauthorized reception, it is common practice to transmit a video signal and / or an audio signal (hereinafter, referred to as “broadcast signal”) in a broadcasting center after performing a scrambling process for electrically stirring the signal. In order to receive this broadcast signal and reproduce it normally, obtain the scramble key used to operate the scrambler at the broadcast center, and use this scramble key to decrypt the descrambler in the pay broadcast reception decoder. You only have to make it work.

[0003] A scramble key is usually mixed with a data signal, multiplexed with a broadcast signal, and distributed to a decoder installed at each receiver's home. Therefore, if a person who does not have a formal contract with a pay broadcasting company obtains the scramble key by some means, even a person other than the contractor can easily receive the pay broadcasting illegally. For this reason,
Even if the scramble key is illegally decrypted, a pay broadcast receiving decoder that minimizes unauthorized reception is required.

[0004]

2. Description of the Related Art FIG. 3 is a block diagram showing an example of a conventional pay-broadcasting transmission / reception system disclosed in a document (Telecommunications Technology Council Council Report No. 44, 1990, p. 76). In FIG. 1, reference numeral 30 denotes a broadcasting center, and reference numeral 40 denotes a conventional pay broadcast receiving decoder. The broadcast center 30 includes a video scrambler 31, an audio scrambler 32, a PN generator 33,
It comprises a multiplexing unit 36, a recipient-specific master key file 37, and encrypting units 38 and 39. The pay broadcast receiving decoder 40 includes a signal separation unit 11, a PN generator 14, a video descrambler 15, an audio descrambler 16, a master key storage unit 41, decryption units 42 and 43, and a contract condition comparison circuit 4.
Consists of four.

In the broadcast center 30, the PN generator 3
3 is set by the scramble key Ks, and the PN sequence (pseudo-random sequence) output from the PN generator 33 is converted into the video scrambler 31 and the audio scrambler 3.
2 and separately scramble the video signal and the audio signal to be broadcast. The above-mentioned scramble key Ks is encrypted by the encryption unit 39 together with common information such as broadcast station identification information and services in order to prevent the information from being known to a third party.

Here, the work key Kw is input to the encryption section 39 as an encryption key at the time of transmitting the scramble key Ks.
The individual information such as the contract details and the decoder ID is input to the recipient-specific master key file 37, and a different master key Kmi is read for each recipient (for each decoder). The master key Kmi is input to the encryption unit 38 as an encryption key, and is used for encryption of the work key Kw and the individual information in the encryption unit 38.

The output signals of the video scrambler 31, the audio scrambler 32, and the encryption units 38 and 39 are supplied to the multiplexing unit 3
6 and multiplexed, and transmitted to each receiver as a scrambled broadcast signal. The scramble key Ks is transmitted for synchronization of the PN generators 33 and 14 for transmission and reception.

[0008] The pay broadcast receiving decoder 40 receives the scrambled broadcast signal, and separates each signal multiplexed in the multiplexing unit 36 by the signal separation unit 11.
As a result, the scrambled video signal is input to the video descrambler 15, the scrambled audio signal is input to the audio descrambler 16, the output encrypted signal of the encryption unit 38 is input to the decryption unit 42, and the encrypted data is further encrypted. Part 3
9 is input to the decryption unit 43.

The decoder 40 has a storage section 41 for storing a unique master key Kmi.
Using i, the decryption unit 42 performs a decryption operation, and decrypts the work key Km and the individual information in the received scrambled broadcast signal. The decrypted work key Kw is input to the decryption unit 43 as a decryption key, and decrypts the scramble key Ks and the common information in the scrambled broadcast signal received here.

The individual information extracted from the decoding unit 42 and the common information extracted from the decoding unit 43 are respectively input to a contract condition comparison circuit 44, where it is automatically determined whether a predetermined contract condition is satisfied. Is done. When the contract conditions are satisfied, an operation signal is output from the contract condition comparison circuit 44 to the PN generator 14. The PN generator 14 generates the same PN sequence as the PN sequence output from the PN generator 33 in the broadcast center 30 when the operation signal is input and the correct scramble key Ks is input from the decryption unit 43. Video descrambler 15 and audio descrambler 1
6 is input.

In this manner, the video descrambler 15
A video signal from which the scramble processing has been canceled is extracted from, and an audio signal from which the scramble processing has been canceled is extracted from the audio descrambler 16.

It is to be noted that there is known a conventional pay broadcast receiving decoder that compares the contract condition comparison by the contract condition comparison circuit 44 with the billing condition read from an external card (for example, see, for example). JP-A-2-111185
No.).

[0013]

In the conventional pay broadcast receiving decoder 40, a decryption master key Kmi (where i is an ID number assigned to each decoder) set for each decoder is stored in the IC chip. 4 in decoder 40 in form
1 and is not easily removable.

However, in the conventional pay-broadcast receiving decoder shown in FIG. 3 or the conventional pay-broadcast decoder in which a charging condition is inputted by a card, the master key Kmi is used.
Is built in the decoder in the form of hardware, so that once the contents of the master key Kmi are decrypted illegally, the work key Kw and the scramble key Ks are respectively decrypted, and a countermeasure is taken. There is no. Only by changing the corresponding master key Kmi in the master key file 37 on the broadcast center side, it can be countered.
Since there is no way to know which master key has been decrypted, it is virtually impossible to change only the corresponding master key Kmi. Further, if the contents of the master key file 37 are completely changed, the receiver who purchases and owns the decoder properly cannot receive it.

On the broadcast center 30 side, each decoder must send out all the master keys for the regular subscribers except for the non-payer and the contract terminator among the different master key information. Therefore, as the number of subscribers increases, it is necessary to perform a complicated and time-consuming operation.

The present invention has been made in view of the above points,
By changing the contents of the master key every fixed period, even if the contents of some master keys are illegally decrypted, the pay broadcast transmission / reception system and the pay broadcast reception can minimize the damage caused by the unauthorized reception. The purpose of the present invention is to provide a decoder.

[0017]

In order to achieve the above object, a pay-broadcast transmission / reception system according to the present invention scrambles at least one of a video signal and an audio signal using a pseudo-random sequence, and sets an initial value of the pseudo-random sequence. The scramble key that determines the value and the section corresponding to the broadcast program
The denomination information is subjected to an encryption process using a master key as an encryption key, multiplexed with the video signal and the audio signal, and transmitted as a scrambled broadcast signal. A receiving decoder converts the video signal and the audio signal from the scrambled broadcast signal. Separate the signal, the encrypted scramble key, and the encrypted charging type information, and decrypt the encrypted charging type information and the encrypted scramble key to determine the initial value of the pseudo-random sequence generator. And a pay-broadcasting transmission / reception system for descrambling the video signal and the audio signal separated after reception using a pseudo-random sequence, wherein a transmission side uses a master key common to all reception decoders as the master key. At the same time, the master key is changed at regular intervals, and the receiving decoder performs decryption for decrypting the encrypted scramble key. Attempt to receive a master key to be used as
The charging information corresponding to the broadcast program to be read is input from a recording medium inserted from the outside , and the input charging information is
Charging type information obtained by decrypting the encrypted charging type information
Video signal and sound separated after reception only when
The voice signal is descrambled using the decrypted scramble key.
This is configured to receive data after performing a bull process .

[0018]

Further, in the pay broadcast receiving decoder according to the second aspect, at least one of the decoders is scrambled.
Video and audio signals, and all receiving decoders
And a master key that is changed at regular intervals is called an encryption key.
Encrypted scramble keys and broadcast programs
Release as a multiplexed signal with the charging type information
Signal and at least one is scrambled
Video and audio signals and encrypted scrambling
Signal separation unit that separates each key and charging type information
And the master key and billing information from a recording medium inserted from outside.
Means for reading the information and information from the reading means.
Encryption input from the signal separation unit using the star key as a decryption key
The encrypted scramble key and the encrypted charging type information.
Decoding unit for decoding, and scrambling from decoding unit
Pseudo-random sequence generator with initial value set by key
And the billing information read by the reading means, and decryption
The charging type information decrypted by the
Run when the information matches the decrypted charging type information.
When an operation permission command is output to the dumb sequence generator to operate
In both cases, when a predetermined charging type is set based on the charging type information,
A charging control unit for calculating a new residual number and a charging control unit
Update the new residual count calculated on the storage medium.
Recording means and a pseudo-random sequence from a pseudo-random sequence generator
The signal is scrambled by the signal separator based on the sequence.
Video signal and / or audio signal
And a descrambler for processing .

[0020]

In the pay broadcast transmission / reception system of the present invention, since the master key in the transmission scrambled broadcast signal is changed at regular intervals, the recording medium externally inserted into the decoder also includes the master in the transmission scrambled broadcast signal. It is possible to change to a recording medium on which the same master key is recorded at regular intervals corresponding to the key.

[0021]

[0022] A pay broadcast receiving data according to claim 2 is also provided.
In the coder, it is inserted externally by the reading means
The master key read from the recording medium is for the recipient.
But not common to all recipients (all decoders)
Since the same master key is used, the pay broadcast receiving decoder
The configuration can be common to all recipients. Ma
When the charging type is a predetermined type, the charging control unit calculates a new remaining number and updates the remaining number on the recording medium by the recording means. Therefore, the transmitting side needs to manage the remaining number. Therefore, pay broadcast reception based on the latest remaining frequency recorded on the recording medium can be always performed.

[0023]

Next, an embodiment of the present invention will be described. FIG. 1 shows a configuration diagram of a first embodiment of the present invention. In FIG.
The same components as those described above are denoted by the same reference numerals. In FIG. 1, reference numeral 10 denotes a pay broadcast receiving decoder according to a first embodiment of the present invention, which includes a signal separating unit 11, a decoding unit 12, and a card reader 1.
3, a PN generator 14, a video descrambler 15, and an audio descrambler 16.

[0024] The card reader 13 is Ru equipment der for reading the recorded information of the IC card 20. The IC card 20 is a recording medium on which a master key Kmx serving as a decryption key for decrypting an encrypted scramble key Ks in a scrambled broadcast signal to be received is recorded. P
The N generator 14 is a circuit for generating a PN sequence which is a pseudo random sequence, and its initial value is set by a scramble key Ks.

Reference numeral 30 denotes a broadcast center, which constitutes a pay broadcast transmitting / receiving system together with the pay broadcast receiving decoder 10. The broadcast center 30 includes a video scrambler 31, an audio scrambler 32, a PN generator 33, and a master key file 3.
4. It is composed of an encryption unit 35 and a multiplexing unit 36. The PN generator 33 is a pseudo-random sequence generator having the same configuration as the PN generator 14. Master key file 3
4 stores a number of master keys Km1 to Kmn, and one of the master keys Km1 to Kmn is selected by an external selection command.
mx is selected. The master key Kmx is changed every fixed period (for example, every six months).

By the way, the contents of the contract for pay broadcasting include:
A flat fee that allows you to view all the programs on that channel by paying a fixed monthly fee for each channel, a program table and a list of rates that combine several programs and rate setting methods are prepared. Tiers that viewers select and subscribe to, pay-per-programs that set fees for individual programs and charge only for viewed programs,
A predetermined fee is set for each unit time, and there is a pay-per-time and the like for charging for viewing time. The present embodiment is a system that is effective for pay-per-view broadcasting of the flat fee system.

Next, the operation of this embodiment will be described.
First, a video signal and an audio signal to be broadcast are input to the corresponding video scrambler 31 and audio scrambler 32, where scramble processing is performed based on the PN sequence supplied from the PN generator 33. Various specific methods of the scrambling process have been proposed (for example, for a video signal, a signal switching method within a scanning line, a scanning line transition method, or a combination thereof, and for an audio signal, a PN signal sequence addition method, etc.). Since these are well known and are not the gist of the present invention, detailed description thereof will be omitted.

The initial value of the PN sequence used for the scrambler in the video scrambler 31 and the audio scrambler 32 is set by a scramble key Ks.
The scramble key Ks is input to the encrypting unit 35, where it is encrypted using the master key Kmx read from the master key file 34 according to the selection command as an encryption key. The master key Kmx is used in common by all receiving decoders, and is changed at regular intervals as described above.

The multiplexing section 36 multiplexes the encrypted scramble key Kmx and the video signal and the audio signal which have been scrambled by the video scrambler 31 and the audio scrambler 32, respectively. The multiplexed signal extracted from the multiplexing unit 36 is transmitted as a scrambled broadcast signal by radio or wire.

A pay broadcast receiving applicant (subscriber) purchases the pay broadcast receiving decoder 10 and the IC card 20 from the pay broadcast broadcasting station (or its agent) in advance. I
Master key information (here, Kmx) is recorded in the C card 20 in advance. When the IC card 20 is inserted into the pay broadcast receiving decoder 10, the recorded information is read by the card reader 13, and the master key Kmx is input to the decryption unit 12 as the decryption key.

On the other hand, the pay receiving decoder 10 receives the scrambled broadcast signal, and separates the scrambled video signal and the scrambled audio signal from the received signal by the signal separating unit 11 to separate the video signal from the received signal. The data is input to the rambler 15 and the audio descrambler 16, respectively, and the encrypted scramble key Ks is separated from the received signal and input to the decryption unit 12.

The decryption unit 12 transmits the encrypted scramble key Ks to the master key Km from the card reader 13.
x is decrypted as a decryption key, and the scramble key Ks used in the broadcast center 30 is decrypted. The decrypted scramble key Ks is input to the PN generator 14 and determines the initial value of the output PN sequence.

As a result, a PN sequence synchronized with the PN sequence output from the broadcast center 33 is extracted from the PN generator 14 and supplied to the video descrambler 15 and the audio descrambler 16 to perform descrambler processing. . As a result, from the video descrambler 15 and the audio descrambler 16, normal video signals and audio signals that have been descrambled are respectively extracted.

In this embodiment, the master key Kmx is changed to a master key of another value (for example, Kmy) after a certain period.
Therefore, an IC in which information of the master key Kmx is recorded
Even if the card 20 is used, a pay broadcast cannot be received. Therefore, the receiver can purchase another IC card in which the information of the new master key Kmy is recorded and insert it into the pay broadcast receiving decoder 10 to receive it again.

Therefore, when the scramble key Ks or the master key Kmx is illegally decrypted by some means, there has been no countermeasure in the past, but according to the present embodiment, the unauthorized device is illegal only for the above-mentioned fixed period at the longest. Because viewing is not possible, damage due to unauthorized viewing can be minimized.

In this embodiment, since the master key Kmx and the like are common to all the pay broadcast receiving decoders 10, all the pay broadcast receiving decoders 10 can have the same configuration. It is possible to reduce the cost, and it is possible to eliminate the complexity of creating a master key file corresponding to a receiver in a conventional broadcasting center. Further, in this embodiment, in order to operate the pay broadcast receiving decoder 10, the IC card 20 must be purchased in advance of the fee. Can be prevented from being uncollected.

Next, a second embodiment of the present invention will be described. FIG. 2 shows a configuration diagram of a second embodiment of the present invention. In the figure, the same components as those of FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 2, reference numeral 10 'denotes a pay broadcast receiving decoder according to a second embodiment of the present invention, in which a card reader / writer 18 and a charging control unit 19 are provided instead of the card reader 13 of the first embodiment. There is a feature.

The card reader / writer 18 is a function for reading recorded information of the IC card, in devices each having a function of writing input information to the IC card, and readings <br/>-up means and recording means and the Make up. Further, the encryption unit 35 'in the broadcast center 30 is configured to encrypt the charging type information together with the scramble key Ks.
This embodiment is a pay-broadcasting transmission / reception system effective for pay-per-view (that is, pay-per-program and pay-per-time).

Next, the operation of this embodiment will be described.
In the broadcast center 30, the encryption unit 35 ′, together with the scramble key Ks, charging type information indicating whether the broadcast program is flat fee or pay-per-view (that is, pay-per-program and pay-per-time) is transmitted from the master key file 34. The master key Kmx is encrypted using the encryption key.

The scramble key Ks and the charging type information encrypted by the encrypting unit 35 'are supplied to the multiplexing unit 36 by the video scrambler 31 and the audio scrambler 32, respectively. The signal is multiplexed with a signal to form a scrambled broadcast signal, which is transmitted wirelessly or by wire.

A pay broadcast receiving applicant (subscriber) purchases the pay broadcast receiving decoder 10 'and the IC card 21 from the pay broadcast broadcasting station (or its agent) in advance of the charge.
The IC card 21 is preliminarily recorded with master key information (here, Kmx) and billing information indicating the remaining number of recipients. When the IC card 21 is inserted into the pay broadcast receiving decoder 10 ′, its recorded information is read by the card reader / writer 18, of which the master key Kmx is input to the decryption unit 12 as a decryption key, Is input to the charging control unit 19.

On the other hand, the pay broadcast receiving decoder 10 ′ receives the scrambled broadcast signal transmitted from the broadcast center 30, and the video signal scrambled from the received signal by the signal separator 11 and the audio signal scrambled from the received signal. Video descrambler 1 that separates signals from each other
5 and the voice descrambler 16 and the scramble key Ks encrypted from the received signal.
And the billing type information are separated and input to the decoding unit 12.

The charging control unit 19 checks the remaining number based on the charging information recorded on the IC card 21 input from the card reader / writer 18, and when the remaining number is not zero ( that is, when the charging information is decrypted). The charging type information
An operation permission signal (instruction) is sent to the PN generator 14 only when it matches). Only when this operation permission signal is input, the PN generator 14 generates a PN sequence based on the scramble key Ks from the decryption unit 12 and supplies it to the video descrambler 15 and the audio descrambler 16, respectively. The video signal and the audio signal from which the scramble processing has been canceled are output.

The charging control unit 19 identifies whether the program currently being received is flat fee or pay-per-view based on the charging type information input from the decoding unit 12. For the IC card 21 held in a state inserted in the decoder 10 ',
Only when it is identified as pay-per-view, the operation of calculating the prescribed fee according to the type of the pay-per-program or pay-per-time, and subtracting the frequency corresponding to the computed prescribed fee from the residual frequency of the IC card 21 to write a new residual frequency. repeat.

In this embodiment, similarly to the first embodiment, the master key Kmx has a different value (for example, Km) after a certain period of time.
y). For this reason, even if the IC card 21 in which the information of the master key Kmx is recorded is used, it is impossible to receive a pay broadcast. Therefore, the reception applicant purchases another IC card in which the information of the new master key Kmy and the charging type information are recorded, and inserts it into the pay broadcast receiving decoder 10 'to receive the information again. can do.

Therefore, the present embodiment also has the same features as the first embodiment, such as being able to minimize the damage caused by unauthorized viewing even if the scramble key Ks or the master key Kmx is illegally decrypted by some means. In addition to this, since the remaining number of the IC card 21 is updated and recorded in addition to the above, there is a feature that charging can be performed reliably.

The present invention is not limited to the above embodiments. For example, the recording medium for recording the master key Kmx and the billing information may be a magnetic card other than an IC card, a compact disk, a magnetic disk, and other recording media. Often,
In addition, by using a circuit that automatically generates a desired master key in response to a selection command instead of the master key file 34, the limitation on the storage capacity may be eliminated. Also,
The present invention can, of course, be applied to a pay-broadcasting transmission / reception system that performs scramble processing on only one of a video signal and an audio signal.

[0048]

As described above, according to the pay broadcast transmission / reception system of the present invention, the recording medium inserted into the decoder from the outside necessary for operating the decoder corresponds to the master key in the scrambled broadcast signal. Therefore, it is necessary to change to a recording medium on which the same master key is recorded at regular intervals, so that even if the scramble key or master key is illegally decrypted by any means, the structure of the decoder is It is possible to minimize the damage caused by unauthorized viewing without complicating the present invention, and to eliminate the complexity of creating a master key file corresponding to a receiver in a conventional broadcasting center.

According to the pay broadcast receiving decoder of the present invention, the pay broadcast receiving decoder is used by using a recording medium in which the same master key is recorded in common to all receivers (all decoders). Can be made common to all the receivers, so that the decoder manufacturing cost can be made lower than before.

Further, according to the pay broadcast receiving decoder of the present invention, when the charging type is a predetermined type, the charging control unit calculates a new residual number and updates and records the residual number on the recording medium by the recording means. This eliminates the necessity of managing the residual number on the transmission side, and allows the pay broadcast to be received based on the latest residual number recorded on the recording medium at all times.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is a configuration diagram of an example of a conventional pay broadcast transmission / reception system.

[Explanation of symbols]

 10, 10 'Pay-broadcast receiving decoder 11 Signal separation unit 12 Decoding unit 13 Card reader 14, 33 PN generator 15 Video descrambler 16 Audio descrambler 18 Card reader / writer 19 Billing control unit 20, 21 IC card 30 Broadcasting center 34 Master key file 35, 35 'Encryption unit

Claims (2)

(57) [Claims] At least one of a video signal and an audio signal is scrambled using a pseudo-random sequence, and a scramble key for defining an initial value of the pseudo-random sequence and charging type information corresponding to the broadcast program are defined as: An encryption process using the master key as an encryption key is performed, and at least one of the multiplexed signals is multiplexed with a scrambled video signal and an audio signal, and the multiplexed signal is transmitted as a scrambled broadcast signal. The video signal and the audio signal from the signal and the encrypted scramble key;
And charging classification information that has been encrypted separated respectively, No. dark
Decrypting the encrypted charging type information and the encrypted scramble key to determine the initial value of the pseudo-random sequence generator,
A pay-broadcasting transmission / reception system for descrambling a video signal and an audio signal separated after reception using the pseudo-random sequence, wherein a master key common to all reception decoders is used as the master key on the transmission side. the master key is changed for every predetermined period together with, in the receiving decoder and the master key used as a decryption key for decoding scrambling key which is the encrypted
The billing information corresponding to the broadcast program to be received is read and input from a recording medium inserted from the outside , and is input.
The accounting information decrypts the encrypted accounting type information.
Only after the reception when it matches the charging type information obtained
Decoded scramble of separated video and audio signals
A pay-broadcasting transmission / reception system, which receives a descrambling process using a key . 2. The method according to claim 1, wherein at least one of the plurality of scrambled pieces
Common video and audio signals and all decoders for reception
And a master key that is changed at regular intervals is called an encryption key.
Encrypted scramble keys and broadcast programs
Release as a multiplexed signal with the charging type information
Signal and at least one is scrambled
Video and audio signals and encrypted scrambling
Signal for separating the charging key and the charging type information from each other.
The master key and the billing information from the recording medium inserted from outside
A reading means for reading the master key from the reading means as a decryption key.
And the encrypted scramble key input from the
Decryption unit for decrypting the encrypted charging type information
And an initial value is set by the scramble key from the decryption unit.
Pseudo-random sequence generator, billing information read by the reading means,
The charging type information decrypted by the decrypting unit is input.
And the charging information matches the decoded charging type information.
When an operation enable command is issued to the pseudo-random sequence generator
To operate it, and based on the charging type information,
Charging control that calculates a new remaining number for a fixed charging type
Unit and the new residual number calculated by the charging control unit.
Recording means for updating and recording on a medium; and a pseudo-random sequence from the pseudo-random sequence generator.
Based on the scrambled signal from the signal separation unit.
Processing of existing video and / or audio signals
A pay-broadcast receiving decoder for use in a pay-broadcast transmission / reception system according to claim 1, further comprising: