JPH06169307A - Coding device and decoding device - Google Patents

Abstract

PURPOSE:To prevent the illicit looking and listening of broadcast programs by performing the transmission and reception of broadcast after changing periodically or at random a ciphering key which is used for the scramble processing of the scramble key used for the scramble processing of the video data. CONSTITUTION:A 2nd ciphering circuit 3 of a coding device 1 serving as a broadcast station ciphers a scramble key KI by the present ciphering key Kjn read out of a ciphering key memory 5 for production and output of a scramble key EKI. This key is transmitted to a decoding device 10. A 1st ciphering circuit 2 ciphers the video data by the key KI and outputs the ciphered data. Then a new ciphering key (Kjn+1) is produced by a new ciphering key generating part 4 periodically or at random. Then the circuit 3 applies the scramble processing to the key (Kjn+1) by the key Kjn read out of the memory 5 for production and output of a new ciphering key (EKjn+1).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoding device and a decoding device suitable for use in, for example, a transmission / reception system for television broadcasting or a transmission / reception system for radio broadcasting.
The present invention relates to an encoding device and a decoding device capable of strongly preventing illegal viewing or listening.

[0002]

2. Description of the Related Art Today, pay television broadcast transmission / reception systems are known. In this pay television transmission / reception system, since the video data is subjected to so-called scramble processing, it cannot normally be viewed. Therefore, a person who wants to view the television broadcast receives the decoder for the television broadcast, for example, in exchange for the contract for paying the viewing fee on a regular basis. By connecting this decoder to a television receiver in the home, the scrambled video data can be descrambled and the television broadcast can be viewed.

Here, as shown in FIG. 3, a pay television broadcast transmission / reception system in which such a scramble process is performed is specifically an encoder 5 on the broadcast station side.
0 and a decode 60 provided in the television receiver in the user's home.

The encoder 50 scrambles the video data supplied through the input terminal 51 with the scramble key KI supplied through the input terminal 52 in the first encryption circuit 53, and outputs it. The scramble key KI is regularly changed.

In the second encryption circuit 55, the encoder 50 scrambles the scramble key KI with the unique key Kj supplied through the input terminal 54 to scramble the key EKj (KI).
And output.

Specifically, the second encryption circuit 55 described above.
Adds the addresses a, b, c, d ... To the unique key K so that each decoder has a different address. Then, the unique key Kj (j
By scrambling the scramble key KI with the above address) to obtain scramble keys EKa (KI), EKb (KI), EKc as shown in FIG.
(KI), EKd (KI) ... Are formed and output.

Each of the scramble keys EKa (KI), E
Kb (KI), EKc (KI), EKd (KI) ...
Is output using the time during which the video data is not transmitted.

Next, the video data output from the encoder 50 as described above is sent to the first decoding circuit 61 of the decoder 60 and the scramble key EKj (K
I) are supplied to the second decoding circuit 62, respectively.

The decoder 60 obtains the scramble key EKj by detecting its own decoder address. Then, in the second decryption circuit 62, the scramble key EKj is descrambled by the unique key Kj supplied through the input terminal 63 and corresponding to the address given to each decoder. Decrypt the scramble key KI. The decrypted scramble key KI is supplied to the first decryption circuit 61.

The first decryption circuit 61 decrypts the video data based on the scramble key KI.
The decoded video data is supplied to the user-side television receiver via the output terminal 64. As a result, the user can watch a pay television broadcast.

In such a pay television transmission / reception system, the video data is the scramble key KI.
Since it has been scrambled by, the program cannot be viewed even if only the video data is received unless it is descrambled with the scramble key KI. Further, even if the scramble key KI can be decrypted by accident, the scramble key KI is regularly changed, so unless the unique key Kj is decrypted to regularly decrypt the scramble key KI, You cannot watch television broadcasts continuously. Therefore, illegal viewing is difficult.

[0012]

However, since the above-mentioned unique key Kj is not changed in the above-mentioned television broadcast transmission / reception system, if the unique key Kj is intentionally or accidentally decrypted, the continuation is continued. There is a risk that it will be illegally viewed.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an encoding device and a decoding device capable of strongly preventing illegal viewing.

[0014]

An encoding apparatus according to the present invention is a transmission information scramble means for scrambling transmission information by using a scramble key and outputting the scramble key, and a scramble processing for the scramble key by using an encryption key. And a scramble key scrambling means for outputting the encrypted key, and an encryption key generating means for generating the encryption key.The encryption key generating means uses the scramble key scrambling means to encrypt a new encryption key with the current encryption. The above-mentioned problem is solved by a feature that the current encryption key is updated to a new encryption key and stored after being scrambled by the encryption key and output.

Further, the decrypting apparatus according to the present invention has been descrambled by a scramble key descramble means for descramble-processing a scramble key transmitted after being scrambled by using an encryption key, and transmitted after being scrambled. The transmission information descramble means for descrambled by the scramble key descrambled by the scramble key descramble means and output, and the encryption key generating means for generating the encryption key, The encryption key generating means descrambles the new encryption key with the current encryption key by the scramble key descrambling means and outputs the new encryption key, and then outputs the current encryption key to the new encryption key. The above-mentioned problems are solved by a feature of updating and storing.

[0016]

In the encoding apparatus according to the present invention, the transmission information scramble means scrambles the transmission information using the scramble key and outputs the scramble key, and the scramble key is generated by the encryption key generating means. Is a scrambling process using scrambling and outputting, wherein the encryption key generating means scrambles a new encryption key with the current encryption key by the scrambling key scrambling means and outputs the new encryption key. After that, the current encryption key is updated to a new encryption key and stored.

Thus, the encryption key is changed regularly or randomly, and the encryption key is scrambled and output.

Further, in the decryption device according to the present invention, the transmission information descramble means descrambles the transmission information using the scramble key and outputs the transmission information.
A decryption device which descrambles and outputs the scramble key using an encryption key generated from an encryption key generating means, wherein the encryption key generating means is a scramble key descramble means. After the new encryption key is descrambled with the current encryption key and output, the current encryption key is updated to the new encryption key and stored.

As a result, the above encryption key, which is regularly or randomly changed, is accurately descrambled.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an encoding device and a decoding device according to the present invention will be described below in detail with reference to the drawings. The encoding apparatus and the decoding apparatus according to the present invention can be applied to, for example, a pay television broadcast transmission / reception system as shown in FIG. In FIG. 1, the left side of the figure is a coding device 1 on the television station side, and the right side of the figure is a decoding device provided on the viewer side television receiver. It is 10.

The encoding device 1 includes a first encryption circuit 2 which is a transmission information scramble means for scrambling and outputting video data which is transmission information by using a scramble key, and an encryption key for the scramble key. The second encryption circuit 3 which is a scramble key scramble means for scrambling a new encryption key with the current encryption key, as will be described later.
And an encryption key generating circuit 8 which is an encryption key generating means for generating the encryption key.

The encryption key generation circuit 8 includes a new encryption key generation unit 4 for generating a new encryption key (Kjn + 1) and the current encryption key (Kjn) for the second encryption circuit 3.
And after the new encryption key is scrambled by using the current encryption key in the second encryption circuit 3, the current encryption key is updated to the new encryption key. And an encryption key memory 5 for storing the data.

On the other hand, the decoding device 10 is a first decoding device which is a transmission information descrambling means for descrambling the video data scrambled and sent from the coding device 1 by using a scramble key. Circuit 1
1 and the scramble key sent from the encoding apparatus 1 after being scrambled is descrambled using the encryption key, and is also scrambled from the encoding apparatus 1 using the current encryption key. A second decryption circuit 12 which is a scramble key descrambling means for descramble-processing the new encryption key sent using the current encryption key, and the above-mentioned descramble processing for the scramble key. While generating an encryption key, the second decryption circuit 12 descrambles the new encryption key with the current encryption key, and then the new encryption key is encrypted with the new encryption key. The encryption key generating circuit 16 is an encryption key generating means for updating and storing the encryption key.

The encryption key generation circuit 16 is descrambled by the encryption key memory 14 for supplying the current encryption key to the second decryption circuit 12 and the second decryption circuit 12. The new encryption key is temporarily stored, and after the new encryption key is descrambled by using the current encryption key in the second decryption circuit 12, the new encryption key is stored in the encryption key memory 14. It is composed of a new encryption key memory 13 for updating the stored current encryption key to a new encryption key.

Next, the operation of the encoding apparatus 1 and the decoding apparatus 10 according to the present embodiment having such a configuration will be described.

First, in this pay television transmission / reception system, so-called scramble processing is applied to the video data. For this reason, a person who wants to view this television broadcast receives the decoding device 10 shown in FIG. 1 which is a decoder for this television broadcast, in exchange for, for example, a contract to pay a viewing fee on a regular basis, and decodes this. By connecting the coding device 10 to a television receiver in the home, the scrambled video data can be descrambled, and the television broadcast can be viewed.

The decoding device 10 has its own decoder address (for example, decoder address = a, b,
c, d ...), and the encryption key memory 1
4 shows a current encryption key Kjn (jn = an, bn, cn, dn ... Where n is the current encryption key) as shown in FIG. 2B. It is stored in advance and passed to the user side.

In such a state, the encoding device 1 on the broadcasting station side supplies the scramble key KI to the first encryption circuit 2 and the second encryption circuit 3 via the input terminal 7, respectively. .

The second encryption circuit 3 encrypts the scramble key KI by using the current encryption key Kjn read from the encryption key memory 5, for example, FIG. 2 (a). Scramble key EKan as shown in
(KI), EKbn (KI), EKcn (KI), EK
scrambling key EKjn (K such as dn (KI) ...
I) is formed and output. This encrypted scramble key EKjn (KI) is the second key of the decryption device 10 side.
Is transmitted to the decoding circuit 12.

On the other hand, the first encryption circuit 2 encrypts the video data using the scramble key KI and outputs it. The encrypted video data is transmitted to the first decoding circuit 11 of the decoding device 10.

Next, in the decryption apparatus 10, the second decryption circuit 12 has been scrambled and transmitted using the current encryption key Kjn read from the encryption key memory 14. Scramble key EKj
scramble key K by descrambling n (KI)
I is formed and is supplied to the first decoding circuit 11.

The first decryption circuit 11 descrambles the scrambled and transmitted video data using the descrambled scramble key KI, and outputs the descrambled video data via the output terminal 15. It is supplied to the television receiver on the user side. As a result, an image can be viewed according to the video data that has been scrambled and transmitted.

Here, the broadcasting station side changes the current encryption key Kjn as shown in FIG. 2B to a new encryption key Kjn + 1, for example, periodically or randomly. This new encryption key Kjn + 1 is used for the new encryption key generation unit 4 described above.
And is supplied to the second encryption circuit 3 and the encryption memory 5.

The second encryption circuit 3 scrambles the new encryption key Kjn + 1 with the current encryption key Kjn read from the encryption memory 5 to form a new encryption key EKjn + 1, This is output by utilizing the time when the video data is not transmitted. The new encryption key EKjn + that has been scrambled
1 is supplied to the second decoding circuit 12 of the decoding device 10. Along with this, the encryption memory 5 is
After the scrambling process by the second encryption circuit 3 is completed, the new encryption key Kjn + 1 is stored. As a result, the encryption key for scrambling the scramble key KI is the current encryption key Kjn.
Is changed to a new encryption key Kjn + 1.

Second decoding circuit 1 of the decoding device 10
When detecting its own decoder address, 2 descrambles the new encryption key EKjn + 1 transmitted together with this decoder address with the current encryption key Kjn read from the encryption memory 14, Create a new encryption key Kjn + 1. This new descrambled encryption key Kjn + 1
Is supplied to the new encryption key memory 13. The new encryption key memory 13 temporarily stores the new encryption key Kjn + 1. Then, in the second decryption circuit 12, after the descrambling process of the new encryption key Kjn + 1 is completed, the new encryption key Kjn once stored.
+1 is supplied to the encryption key memory 14. As a result, the current encryption key Kjn stored in the encryption memory 14 is changed to the new encryption key Kjn + 1.

The broadcasting station side changes the encryption key as described above by using a time zone during which video data is not transmitted or received. When the change of the encryption key is completed, the first encryption circuit 2 scrambles the video data with the scramble key KI and outputs the scramble key KI as described above. The new encryption key Kjn + read from the encryption memory 5
1, the scramble processing is performed and the result is output. The scrambled video data is transmitted to the first decryption circuit 11 of the decryption device 10, and the scrambled scramble key EKjn + 1 (KI) is transmitted to the second decryption circuit 12.

Second decoding circuit 1 of the decoding device 10
2 uses the new encryption key Kjn + 1 read from the encryption key memory 14 to generate the scramble key EKj.
The scramble key KI is formed by descrambling n + 1 (KI), and the scramble key KI is supplied to the first decryption circuit 11.

The first decryption circuit 11 decrypts the scrambled and transmitted video data with the new encryption key Kjn + 1 to obtain a scramble key KI.
The data is descrambled and supplied to the television receiver through the output terminal 15. As a result, an image corresponding to the descrambled video data can be viewed.

As is clear from the above description, the encoding apparatus and the decoding apparatus according to the present embodiment periodically or repeatedly provide the encryption key for scrambling the scramble key for scrambling the video data. Since the encryption key is randomly changed and transmitted and received, even if the encryption key is intentionally or accidentally decrypted once, the possibility that the encryption key is continuously decrypted is extremely low, and thus illegal viewing is strongly prevented. be able to.

Further, since the encryption key is scrambled and transmitted / received, the possibility that the scramble key can be accidentally deciphered can be extremely reduced, and the illegal viewing can be prevented more strongly. You can

In the above description of the embodiments, the present invention is applied to the transmission / reception system of television broadcasting, but this is only an example. In addition, the transmission / reception system of radio broadcasting and the telephone system, It is needless to say that the present invention can be applied to a conference system or the like for holding a conference while staying in a remote place, and can be applied to any system as long as it is a system that scrambles information and transmits / receives it.

[0042]

As described above, the encoding device and the decoding device according to the present invention change the encryption key for scrambling the scramble key for scrambling the transmission information periodically or randomly. Even if the encryption key is intentionally or accidentally decrypted, it is extremely unlikely that the encryption key is continuously decrypted, and thus illegal acquisition of transmission information can be strongly prevented.

Further, since the encryption key is scrambled and transmitted / received, the possibility that the scramble key can be accidentally deciphered can be extremely lowered, and the illegal acquisition can be more strongly prevented. You can

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment in a case where an encoding device and a decoding device according to the present invention are applied to a transmission / reception system for television broadcasting.

FIG. 2 is a schematic diagram showing an example of a scramble key used in the television broadcast transmission / reception system of the above embodiment and individual encryption keys of the scramble key.

FIG. 3 is a block diagram of a conventional television broadcast transmission / reception system.

FIG. 4 is a schematic diagram showing an example of a scramble key used in the conventional television broadcast transmitting / receiving system.

[Explanation of symbols]

 1 ... Encoding device 2 ... First encryption circuit 3 ... Second encryption circuit 4.・ ・ ・ ・ ・ ・ ・ New encryption key generator 5 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Encryption key memory 6, 7 ・ ・ ・ ・ ・ ・ Input terminal 8 ・ ・ ・ ・・ ・ ・ Encryption key generation circuit 10 ・ ・ ・ ・ ・ ・ Decryption device 11 ・ ・ ・ ・ ・ ・ ・ First decryption circuit 12 ・ ・ ・ ・ ・ ・ ・ ・ ・ Second Decryption circuit 13 ... New encryption key memory 14 ... Encryption key memory 15 ... Output terminal 16 ... ... Cryptographic key generation circuit

Claims (2)

[Claims] 1. A transmission information scramble means for scrambling and outputting transmission information by using a scramble key, a scramble key scramble means for scrambling and outputting the scramble key by using an encryption key, and the above encryption. Encryption key generating means for generating a key, wherein the encryption key generating means scrambles a new encryption key with the current encryption key by the scrambling key scrambling means and outputs the new encryption key, An encoding device, characterized in that the current encryption key is updated to a new encryption key and stored. 2. A scramble key descramble means for descramble-processing a scramble key that has been scrambled and transmitted using an encryption key, and scramble key descrambler for the transmission information that has been scrambled and transmitted. The transmission information descramble means for descramble processing with the scramble key descrambled by the means and output, and the encryption key generation means for generating the encryption key, wherein the encryption key generation means is The scramble key descramble means descrambles a new encryption key with the current encryption key and outputs the new encryption key, and then the current encryption key is updated to a new encryption key and stored. Decryption device.