JPH07202884A - Transmitter and receiver - Google Patents

Abstract

PURPOSE:To simply and surely update a ciphering key for subscription broadcast efficiently. CONSTITUTION:A ciphering decoder 104 decodes received individual information 152 by using a master key Kmi and stores a work key KW included therein. A ciphering decoder 103 decodes received common information 151 by using the work key KW. A PN signal generator 107 uses a scramble key KS to generate a P signal. A descrambler 105 descrambles received data 150 by using the PN signal. Update time information included in the individual information decoded by the ciphering decoder 104 is stored in a time information storage section and a timer 109 and a power supply 125 is energized when the stored time comes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitter and a receiver suitable for use in a pay broadcast transmitter / receiver for automatically updating a work key used in pay broadcast, for example.

[0002]

2. Description of the Related Art Conventionally, encryption used in pay broadcasting usually has a hierarchical structure and is encrypted by using a plurality of keys. Further, the key is periodically updated on the transmitting side so that the key is not sequentially discovered through trial and error inspection.

A hierarchical structure of keys in the conventional pay satellite broadcasting system will be described with reference to FIG. As shown in FIG. 4, a conventional hierarchical key is a triple key (scramble key KS,
It is composed of a work key KW and a master key Kmi). First, on the sending device 210 side, which is an encoder, the data from a data sending device (not shown) is scrambled by the scrambler 201 with the scramble key KS, which is common information, and sent, and on the receiving device 220 side, which is the decoder, the descrambler 205. To descramble. At this time,
As will be described later, descrambling can be performed only when the receiving contract is valid.

The scramble key KS input to the scrambler 201 is updated in a very short cycle (for example, 1 second), and the work key KW having a relatively long update cycle is used so that the scramble key KS is not decrypted. The encrypted data is transmitted to the receiving device 220. Here, the sending device 210
Is a receiver 220 which is a decoder delivered to the contractor.
A unique ID assigned to each and a master key Kmi corresponding thereto are stored in the storage unit 204 in advance. Then, the work key KW assigned to each individual is encrypted by the encryptor 203 using the master key Kmi unique to each decoder and transmitted to the receiving device 220.

In the receiving device 220, which is a decoder, the work key KW in the individually transmitted individual information output from the encryptor 203 is used as a master key Kmi stored in the storage unit 208 and unique to each decoder. Use encryption / decryption unit 207
Decode with and store. Then, with the stored work key KW, the scramble key KS in the common information output from the encryptor 202 is decoded and stored. The descrambler 205 descrambles the output information from the scrambler 201 with the stored scramble key KS. In this way, when the receiving contract is valid (master key Kmi, work key K
Only when W and the scramble key KS are correct, reception (descramble) can be performed. Then, the decoded data is output to a service decoder (not shown).

When the work key KW unique to each person is encrypted with the master key Kmi unique to the decoder and transmitted (updated) at a predetermined timing, the next work key should be delivered during the update cycle. However, by increasing the length of the update cycle, the number of subscribers can be increased because the individual information of the subscribers can be transmitted by that amount. So now, for example, JS
In B (Japan Satellite Broadcasting), the work key KW is updated once
It is said to be the year. At the time of updating, the decoder needs to be in the power-on state, that is, to watch the JSB.
Nowadays, it notifies the time of renewal in the form of direct mail or announcement broadcasting, and turns on the power to subscribers. In addition, since the viewer may not be able to receive the work key in one transmission, it is sent several times, and if it is not updated even after that, or when there is a complaint, send it individually. Is dealt with.

[0007]

However, as described above, the conventional method of updating a work key requires manual operations such as direct mail and announcement broadcasting, and the procedure increases as the number of subscribers increases. There is a problem that management becomes complicated. In addition, since the subscriber is left to turn on the power of the decoder, there is a possibility that the work key may not be updated without turning on the power. Actually, for example, about 1% in the current BS pay broadcasting
The decoder of is not updateable.

[0008] Further, although there are few services (pay programs) at present, there are few troubles. However, if many services are provided by satellite data broadcasting in the future, a work key is required for each service and the update of the work key is required. It is considered that more troubles will occur. Furthermore, the subscriber may continue to turn on the power switch of the device in order to reliably update the work key, which may result in unnecessary power consumption.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transmitting device and a receiving device that can efficiently and easily update an encryption key.

[0010]

The transmitting apparatus of the present invention includes a common information generating circuit 3 as first generating means for generating common information including a scramble key KS as information to be transmitted, and a scramble key KS. A work key KW as an encryption key for encryption, an individual information generation circuit 5 as second generation means for generating individual information as update information for updating the work key KW, and an individual information generation circuit 5 are generated. An encryption device 6 as a first encryption means for encrypting the scramble key KS generated by the common information generating circuit 3 in correspondence with the work key KW, and a second encryption device for encrypting the work key KW and the update information. An encryption device 8 as an encryption device, a scramble key KS encrypted by the encryption device 6, a work key KW encrypted by the encryption device 8 and a transmission circuit 9 as a transmission device for transmitting update information. Characterized in that it obtain.

The receiving device of the present invention is a receiving device for receiving transmitted information, a work key KW, and update information of the work key KW by using the work key KW as an encryption key updated at a predetermined timing. , A time information storage unit and a timer 109 as a first storage means for storing update information.
A power supply control unit 121 as a control unit that controls the power supply 125 based on the update information stored in the time information storage unit and the timer 109; and a second work key KW that is updated based on the update information. Encryption device 1 as storage means
04 and a decryption device 1 as a decryption means for decrypting information based on the work key KW stored in the decryption device 104.
03 and are included.

When the update information includes the update start time for updating the work key KW, the time information storage section and the timer 109
Can turn on the power supply 125 for a certain time at the update start time.

When the update information includes the update start time for updating the work key KW and the update period for the work key KW, the time information storage section and the timer 109 cause the power supply 1 to operate at the update start time.
25 can be turned on, and the power supply 125 can be turned off after a lapse of time corresponding to the update period.

When the update information includes the update start time for updating the work key KW and the update end time for the work key KW,
The time information storage unit and the timer 109 turn on the power supply 125 at the update start time and the power supply 1 at the update end time.
25 can be turned off.

[0015]

In the transmitting apparatus having the above structure, the scramble key KS encrypted by the encryptor 6, the work key KW encrypted by the encryptor 8 and the update information are transmitted to the transmission line by the transmitting circuit 9. Therefore, it is possible to reliably update the work key KW without wasting power.

In the receiving device having the above configuration, the encryption / decryption unit 10
4 rewrites and stores the work key KW each time it is updated. Further, the time information storage unit and the timer 109 store the update information. The power supply control unit 121 controls the power supply 125 based on the control signal from the time information storage unit and the timer 109, so that the work key KW can be efficiently updated easily and reliably.

[0017]

1 to 3 relate to an embodiment of a pay broadcast transmitting apparatus and a receiving apparatus to which the transmitting apparatus and the receiving apparatus of the present invention are applied, and FIG. 1 shows an embodiment of an encoder which is a pay broadcasting transmitting apparatus. 2 is a block diagram showing a configuration of a main part of FIG. 2, FIG. 2 is an explanatory view for explaining a configuration example of individual information used in the encoder of FIG. 1, and FIG. 3 is a main configuration of an embodiment of a decoder which is a pay broadcast receiving device. It is a block diagram showing.

In the encoder of FIG. 1, data to be transferred (character data of newspapers, magazines, etc.) output from the data supply device 1 is supplied to the scrambler 2,
It is designed to be scrambled. It is included in the common information generated by the common information generation circuit 3. The scramble key KS is supplied to the PN signal generator 4, and the PN signal generator 4
The generated PN signal is supplied to the scramble 2. Scramble key KS output by common information generation circuit 3
And the common information including the program number corresponding thereto is supplied to the encryption device 6 and is encrypted corresponding to the work key KW among the individual information output from the individual information generation circuit 5. There is.

Further, the individual information output from the individual information generating circuit 5 (including the contract contents, the work key KW, the next update time information, etc., as described with reference to FIG. 2) is supplied to the encryptor 8. Master key Kmi generated by the master key generation circuit 7
It is designed to be encrypted according to.

The transmission circuit 9 includes a scrambler 2 and an encoder 6.
In addition, the data supplied from the encryptor 8 are combined and transmitted to the satellite, for example, via the antenna 10.

FIG. 2 shows an example of the individual information output by the individual information generating circuit 5. As shown in the figure, the individual information includes encoded identification information 161 (16 bits), related information identification information 162 (2 bits), and user ID 163 (3).
2 bits), work key (KW) 164 (32 bits),
Work key target program information 165 (PV, SV, PR: 40
Bit), contract registration code 166 (12 bits), key expiration date information 167 (11 bits), individual information transmission scheduled date / time information 168 (10 bits), tampering detection information 169
(16 bits) and other information 170 (5 bits), which is based on the report of the Electrical Engineering Council.

As described above, the common information includes information common to each recipient, but the individual information includes information different for each recipient.

Next, the operation of the embodiment shown in FIG. 1 will be described. Scramble key KS generated by common information generation circuit 3
Are supplied to the PN signal generator 4. PN signal generator 4
Generates a PN signal corresponding to the input scramble key KS and supplies it to the scrambler 2. Scrambler 2
Scrambles the data supplied from the data supply device 1 in accordance with the PN signal input from the PN signal generator 4, and outputs the scrambled data to the transmission circuit 9. This scramble key K
S changes (updates) in a relatively short cycle (eg, every second)
To be done.

Of the individual information output by the individual information generating circuit 5, the work key KW is supplied to the encryption device 6. The encryption device 6 encrypts the scramble key KS supplied from the common information generation circuit 3 in correspondence with this work key KW,
Output to the transmission circuit 9. This scramble key KS is output at least once during the update cycle (1 second).

Further, the encryption unit 8 includes a master key generation circuit 7
The master key Kmi that generates
Corresponds to this master key Kmi, and the individual information generation circuit 5
The input individual information is encrypted and output to the transmission circuit 9.

The transmission circuit 9 includes a scrambler 2 and an encoder 6.
And the data supplied from the encryption device 8 are combined and transmitted to the satellite by radio waves via the antenna 10.

The information thus transmitted is transmitted by radio waves to the decoder shown in FIG. 3 via the satellite.

In the decoder of this embodiment, as shown in FIG. 3, the pay broadcast transmitted from the satellite is transmitted to the BS tuner 101.
To receive. The bit stream output from the BS tuner 101 is input to the packet separation circuit 102, and the encrypted data 150, common information 151 (program number, scramble key KS, etc.), individual information 152 (contract details, work key KW, Next update time information, etc.) is separated into three types of packets. Incidentally, 101 is not limited to the BS tuner, but may be a CS tuner or a CATV terminal.

The data 150 is data scrambled by the scramble key KS, and the common information 151 is
It is encrypted with the work key KW and is composed of the program number of the data 150, the scramble key KS, and the like. Also,
The individual information 152 as shown in FIG. 2 is encrypted with the master key Kmi.

The separated individual information 152 (work key (K
W ') 164) is decrypted by the encryption / decryption unit 104 by using the master key (Kmi) 131 having each decoder and stored in advance in the storage unit 105, of which the work key KW is stored. To be done. Then, the stored work key (KW) 132 is input to the encryption / decryption device 103, and using this, the encryption / decryption device 103 decrypts the common information 151 (including the scramble signal K S ′) and scrambles it. The key (KS) 133 is the PN signal generator 107.
Entered in.

The condition comparator 108 stores the contract conditions in the individual information 152 supplied from the encryption / decryption device 104, and stores the stored contract conditions and the contents of the common information 151 input from the encryption / decryption device 103. In comparison, if the contract condition matches the content of the common information 151, the enable signal 134 is output to the PN signal generator 107. When the enable signal 134 is input, the PN signal generator 107 receives the scramble key KS13 from the encryption / decryption unit 103.
A PN signal is generated based on 3, and the descrambler 106
Output to.

Then, the descrambler 106 descrambles the data 150 by the PN signal to program data 1
35 is obtained and output to the service decoder 120. The service decoder 120 decodes the program data 135,
It is output to a TV, a dedicated terminal, etc. not shown.

On the other hand, the individual information transmission scheduled date / time information 168 (representing the next individual part information transmission scheduled date / time) as the update information in the individual information 152 decrypted by the encryption / decryption unit 104 is
It is output to the time information storage unit and the timer 109. The time information storage unit and timer 109 stores the individual information transmission scheduled date and time information 168 and sets the timer. The time information storage unit and the timer 109 output a control signal to the power supply control unit 121 when the stored next individual information transmission scheduled time comes, and the power supply control unit 121 turns on the power supply 125 of the decoder by this control signal. Therefore, the decoder is surely in the operating state upon updating, receives the individual information 152, updates the work key KW, and stores it in the encryption / decryption base 04.

Since the transmission period of individual information can be predicted in advance during the power-on period, it is set to a fixed time (for example, 1 hour), and the work key KW is updated during that period and stored in the encryption / decryption base 104. Then, the power supply 125 is turned off.

As described above, according to the decoder of this embodiment,
The power supply control unit 121 automatically turns on the power supply 125 according to the control signal from the time information storage unit and the timer 109, receives the individual information 152 in the power-on state, updates the work key KW, and sends it to the encryption / decryption unit 104. Since it is stored, the individual information of the pay broadcast can be efficiently updated easily and surely.

The power-on control is not limited to the method of the above-described embodiment (on for a fixed time), and the individual information transmission scheduled date / time information 16 is used as the work key update time information in the individual information 152.
In 8, the work key update start time and the duration for turning on the power from this work key update start time are set, and the time information storage unit of the decoder and the timer 109 turn on the power at the work key update start time and continue. By turning off the power after a lapse of time, the work key KW is updated, and the encryption / decryption unit 10
4 may be stored.

In this case, in addition to the above effects, by setting the update start time and the duration for turning the power on in the individual information, it is possible to flexibly cope with the variation of the next individual information transmission time due to the increase / decrease of subscribers and the change of service. Can be dealt with.

As another method of controlling the power-on, as work key update time information in the individual information 152,
The work key update start time and the work key update end time may be set, and the power may be turned on / off by the time information storage unit of the decoder and the timer 109 based on these two pieces of information.

The work key update start time and the work key update end time in the specific individual information 152 are, for example, generally considered to be a work key update cycle of about once a month. Considering this, 5 bits for "day" and 5 bits for setting "time" in hour unit, total 1
It may be configured to use 0 bits. By doing this, when the next update time is clear (that is, when there is no sudden increase in the number of subscribers or changes in the selected programs)
In, it becomes possible to control the power supply of the decoder more efficiently.

The portion related to encryption and decryption in FIG. 3 (inside the broken line in the figure) is called the security module,
Recently, algorithms and work keys KW have been applied to IC cards, etc.
It tends to be separated from the main body of the decoder by providing the recording part of the.
The same effect can be obtained by recording in.

In the above embodiment, the encryption key is triple, but it may be four or more, or single or double.

[0042]

As described above, according to the transmitting apparatus of the present invention, the encryption key and the update information are transmitted.
It is possible to reliably update the encryption key without wasting power.

Further, according to the receiving apparatus of the present invention, the encryption key is rewritten and stored for each update, and the power supply is controlled based on the update information. Therefore, the encryption key can be updated easily and reliably and efficiently. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a main part of an embodiment of an encoder that is a transmission device of the present invention.

FIG. 2 is an explanatory diagram illustrating a configuration example of individual information used in the encoder in FIG.

FIG. 3 is a block diagram showing a configuration of a main part of an embodiment of a decoder which is a receiving device of the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional pay broadcast transmitter and receiver.

[Explanation of symbols]

 1 data supply device 2 scrambler 3 common information generation circuit 4 PN signal generator 5 individual information generation circuit 6 cipherer 7 master key generation circuit 8 cipherer 101 BS tuner 102 packet separation circuit 103, 104 encryption / decryption device 105 storage unit 106 Descrambler 107 PN signal generator 108 Conditional comparator 109 Time information storage and timer 120 Service decoder 121 Power supply control unit 125 Power supply

Claims (5)

[Claims] 1. A first generating means for generating information to be transmitted, an encryption key for encrypting the information, a second generating means for generating update information for updating the encryption key, and the second means. Corresponding to the encryption key generated by the generating means, the first encryption means for encrypting the information generated by the first generating means, and the second encryption means for encrypting the encryption key and the update information. An encryption unit; and a transmission unit for transmitting the information encrypted by the first encryption unit, the encryption key encrypted by the second encryption unit, and the update information. Transmitting device. 2. A receiving device for receiving the transmitted information, the encryption key, and the update information of the encryption key by using an encryption key updated at a predetermined timing, and a first device for storing the update information. Storage means, control means for controlling a power supply based on the update information stored in the first storage means, and second storage means for storing the encryption key updated based on the update information means, And a decryption unit that decrypts the information based on the storage key stored in the second storage unit. 3. The update information includes an update start time for updating the encryption key, and the control unit turns on the power supply for a certain period of time at the update start time. Receiver. 4. The update information includes an update start time for updating the encryption key and an update period of the encryption key, and the control means turns on the power at the update start time and The receiving device according to claim 2, wherein the power supply is turned off after a corresponding time has elapsed. 5. The update information includes an update start time for updating the encryption key and an update end time for the encryption key, and the control unit turns on the power at the update start time and completes the update. The receiving device according to claim 2, wherein the power supply is turned off at a time.