JP2004172870A - Scramble broadcasting system for streamed-media data - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scramble broadcasting system for streamed-media data that can easily perform scramble broadcasting of streamed-media data without requiring any special exclusively used hardware etc., for encoding and decoding scramble broadcasts by encoding and decoding the streamed-media data at high speeds. <P>SOLUTION: In this scramble broadcasting system, a downloading side downloads the streamed-media data through a communication channel by encoding the data based on a cryptographic key, and a receiving side decodes the downloaded data based on the cryptographic key. The system is provided with a key bit pattern generating device 30 which generates key bit patterns having prescribed numbers of bits as the cryptographic key. On the downloading side, the streamed-media data are encoded at prescribed time intervals by using different key bit patterns generated from the generating device 30. On the receiving side, the streamed-media data are decoded by using the same key bit patterns as those used on the downloading side. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a stream media data scramble broadcast system, and more particularly to a stream media data scramble broadcast system that can easily perform encoding and decoding without requiring special hardware or the like.
[0002]
[Prior art]
As for stream media data broadcasting such as stream media data distribution broadcasting, satellite broadcasting, and cable television broadcasting using the Internet, scramble broadcasting for protecting contents is required for business reasons. Conventionally, encryption algorithms such as DES, AES, and RSA have been mainly used for scrambling the stream media data.
[0003]
While these algorithms can perform strong encryption, encoding / decoding with software requires a lot of processing, especially when performing real-time encoding / decoding such as broadcast data. Requires dedicated hardware. Although the scramble device for the broadcast service needs to be widely spread in each home, such a problem in cost is a barrier to spread.
[0004]
As a conventional technique relating to a scramble broadcasting method of stream media data, for example, a technique disclosed in Japanese Patent Application Laid-Open No. 8-288939 has been proposed. In Japanese Patent Application Laid-Open No. 8-288939, a broadcast cell is encrypted with an encryption key generated by an encryption key generation unit of a line termination device, and a subscriber terminal encrypts a broadcast cell using a pre-assigned encryption key. A method for decoding is disclosed.
[0005]
[Problems to be solved by the invention]
As described above, in the conventional stream media data scramble broadcasting method, since a special encryption algorithm is used, it is necessary to provide dedicated hardware for scrambling the stream media data. Was costly to implement, and was a factor that hindered its spread.
[0006]
For example, the technology disclosed in Japanese Patent Application Laid-Open No. 8-288939 also requires a dedicated hardware device for encrypting a broadcast cell with an encryption key and for decrypting the encrypted broadcast cell.
[0007]
An object of the present invention is to perform high-speed encoding and decoding on stream media data, and to easily perform scrambled broadcasting without special hardware or the like for encoding and decoding. An object of the present invention is to provide a scramble broadcasting method for stream media data.
[0008]
It is another object of the present invention to provide a stream media data scramble broadcasting system capable of performing high-speed encoding and decoding even by software processing.
[0009]
It is still another object of the present invention to provide a stream media data scramble broadcasting system capable of increasing the strength of a key in scrambling stream media data to a practical level.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a scrambled broadcast of stream media data in which a distribution side encodes stream media data with an encryption key and distributes the stream media data through a communication line, and a reception side decrypts the distributed stream media data with the encryption key. The system further includes a key bit pattern generation device that generates a key bit pattern having a predetermined number of bits as the encryption key, and the distribution side performs a predetermined time interval at a different time interval from the key bit pattern generation device. The stream media data is decoded using a key bit pattern, and the receiving side decodes the stream media data using the same key bit pattern as the distribution side.
[0011]
The scramble broadcasting system of the present invention according to claim 2, wherein the key bit pattern is changed for each fixed amount of stream media data, so that the distribution side and the reception side can code based on the fixed amount of data. The key bit pattern used for encryption and decryption is changed.
[0012]
The scramble broadcasting system according to the third aspect of the present invention performs the encoding and the decoding by performing an exclusive OR operation on the input stream media data using the key bit pattern. I do.
[0013]
The scramble broadcasting system according to a fourth aspect of the present invention is characterized in that the number of bits of the key bit pattern is increased or decreased according to the type of the stream media data.
[0014]
The scramble broadcasting system according to claim 5, wherein the encoding is performed by using two bit patterns of the key bit pattern generated by the key bit pattern generation device and a bit pattern obtained by inverting the key bit pattern. And decoding.
[0015]
In the scramble broadcasting system according to the present invention, when encoding the stream media data, information for uniquely identifying the key bit pattern is embedded in the stream media data, and the stream media data is decoded. In this case, the key bit pattern used for decryption is obtained from the key bit pattern generation device based on the embedded key bit pattern information.
[0016]
The present invention according to claim 7 is a stream media data scramble broadcasting system in which a distribution side encodes stream media data using an encryption key and distributes the stream media data via a communication line, and a reception side decrypts the distributed stream media data using an encryption key. A scramble processing program for executing encoding and decoding of the stream media data, wherein the distribution side generates a key bit pattern of a predetermined number of bits as the encryption key at predetermined time intervals. Performing a function of decoding the stream media data using a different key bit pattern generated from the pattern generation device, the receiving side, the stream media data using the same key bit pattern as the distribution side Performing the function of decrypting .
[0017]
9. The scramble processing program according to claim 8, wherein the key bit pattern is changed for each constant data amount of the stream media data, so that the distribution side and the reception side can code based on the constant data amount. And a function of changing the key bit pattern used for encryption and decryption.
[0018]
The scramble processing program of the present invention according to claim 9, having a function of performing the encoding and decoding by performing an exclusive OR operation on the input stream media data using the key bit pattern. It is characterized by.
[0019]
A scramble processing program according to a tenth aspect of the present invention is characterized in that the program has a function of increasing or decreasing the number of bits of the key bit pattern according to the type of the stream media data.
[0020]
The scramble processing program of the present invention according to claim 11, wherein the key bit pattern generated by the key bit pattern generation device and the bit pattern obtained by inverting the key bit pattern are used for the encoding. And decoding.
[0021]
The scrambling processing program according to the twelfth aspect of the present invention has a function of embedding information for uniquely identifying the key bit pattern into the stream media data when encoding the stream media data. At the time of decryption, it has a function of acquiring the key bit pattern used for decryption from the key bit pattern generation device based on the information of the embedded key bit pattern.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
[0023]
FIG. 1 is a block diagram showing a system configuration of an embodiment to which a stream media data scramble broadcasting system according to the present invention is applied.
[0024]
The system according to this embodiment includes a scrambler 10 that encodes (scrambles) stream media data, a scrambler 20 that decodes (descrambles) encoded stream media data, and an encoding / scrambler 20. It includes a key bit pattern generation device 30 that generates a key bit pattern for taking an exclusive OR in a decryption process.
[0025]
As an example shown in FIG. 2, the scramble device 10 is provided as a function or as an option to a server 100 or the like of a service provider (service provider or the like) that provides a distribution service of stream media data as content over a communication line such as the Internet. The stream encoding unit 12 is provided with a predetermined key bit pattern distributed from the key bit pattern generation device 30 and managed by the key bit pattern management unit 11 for the input raw stream media data. Encoding processing by exclusive OR is performed.
[0026]
Further, identification information for uniquely identifying a key bit pattern used for encoding is embedded in the encoded stream media data. By using this identification information, a necessary key bit pattern can be requested from the key bit pattern generation device 30 when the descrambling device 20 decodes the stream media data.
[0027]
In addition, the scrambler 10 is not limited to a service provider that provides a distribution service of stream media data as content on a communication line such as the Internet as described above. The distribution device is also provided as its function or as an option.
[0028]
The coded stream media data is output from the stream coding unit 12, distributed over a network such as the Internet by packet communication or the like, and input to the descrambler 20.
[0029]
The descrambling device 20 may be provided as a function or an option (for example, to a client terminal (receiving device) 200 of a user who receives (receives a broadcast) stream media data as content, as shown in an example in FIG. A predetermined key distributed from the key bit pattern generation device 30 and managed by the key bit pattern management unit 21 with respect to the input coded stream media data. Using the bit pattern, the stream decoding unit 22 performs decoding processing by exclusive OR. The decoded stream media data is output from the stream decoding unit 22, is provided to the user's client terminal 200, and is displayed on the image display device.
[0030]
If the user receives a cable television broadcast, the descrambling device 20 is provided as, for example, a function or option of a cable television set-top box.
[0031]
The key bit pattern generation device 30 is connected to a device such as the server 100 of the broadcast service provider and a device such as the client terminal 200 of the user via a communication line such as the Internet. A predetermined key bit pattern used for encoding and decoding by sum is generated and distributed.
[0032]
The key bit pattern generation device 30 has an independent key bit pattern distribution service provider server 300 that distributes a predetermined key bit pattern to a service provider and a user as shown in an example in FIG. Or it is provided as an option.
[0033]
The key bit pattern management unit 11 and the key bit pattern management unit 21 request the key bit pattern generation device 30 to distribute the key bit pattern periodically or for each predetermined data amount.
[0034]
In addition, the server 300 of the key bit pattern distribution service provider counts and manages the distribution amount (number of distributions) of the key bit pattern for each user who receives the stream media data, so that the user can respond in accordance with the counted value. It is also possible to provide a service of collecting a charge (viewing fee) for the content and paying it to a broadcasting service provider.
[0035]
In this manner, by collecting a charge according to the distribution amount of the key bit pattern necessary for decoding the stream media data, it is possible to reliably perform an appropriate charge according to the amount of the stream media data that is received. Also, it is possible to reduce the burden associated with collecting charges for broadcasting service providers.
[0036]
Next, the operation of the present system configured as described above will be described in detail with reference to FIGS.
[0037]
First, an operation of performing encoding processing (scramble processing) on raw stream media data will be described.
[0038]
Raw stream media data input to the scrambler 10 shown in FIG. 1 is encoded by the stream encoding unit 12 using a predetermined key bit pattern managed by the key bit pattern management unit 11. The detailed algorithm will be described with reference to FIG. 4 and the flowchart of FIG.
[0039]
The raw stream media data 40 shown in FIGS. 3 and 4 is the stream media data before being encoded and input to the scrambler 10. The key bit pattern 50 is a key bit pattern generated by the key bit pattern generation device 30 and used to perform an exclusive OR operation with the raw stream media data 40 passed through the key bit pattern management unit 11. The number of bits of the key bit pattern 50 is arbitrary, but the encoding process and the decoding process in FIGS.
[0040]
As the key bit pattern, in actual operation, for example, the number of bits such as 32 bits, 128 bits, and 512 bits is used. Since the confidentiality of the coded stream media data increases in proportion to the strength as a key of the key bit pattern, if the confidentiality is desired to be increased, the number of bits of the key bit pattern is increased so that it cannot be easily released. However, even if the number of bits of the key bit pattern is increased more than necessary, the degree of confidentiality does not change much, and only processing takes time.
[0041]
The number of bits of the key bit pattern may be changed according to the type of stream media data (movie, news, etc.), that is, according to confidentiality.
[0042]
When the scrambler 10 receives the input of the raw stream media data 40 (step 101 in FIG. 7), the key bit pattern 50 serving as a key for performing the scramble processing of the raw stream media data 40 exists in the key bit pattern management unit 11. It is confirmed whether or not to perform (Step 102). That is, it is confirmed whether the key bit pattern 50 currently used exists in the key bit pattern management unit 11. The key bit pattern management unit 11 holds the key bit pattern currently used for encoding until the key bit pattern is changed.
[0043]
If the key bit pattern 50 does not exist, a request is issued to the key bit pattern generation device 30 to receive the key bit pattern (step 103). When the key bit pattern 50 is held, the encoding process is executed in the following procedure (steps 104 to 108).
[0044]
First, the exclusive OR of the 4 bit data (bit number 1 to bit number "1001") from the head of the raw stream media data 40 and the key bit pattern 50 is calculated (step 105).
[0045]
While determining whether or not all the raw stream media data 40 has been scrambled (step 106), the generated bit string “0100” is stored as the scrambled stream data 61 (step 107).
[0046]
Subsequently, the exclusive OR of the data of the next 4 bits (“1010” of bit number 5 to bit number 8) in the raw stream media data 40 and the key bit pattern 50 is calculated. The generated bit string “0111” is concatenated to the continuation of the stored scrambled stream data 61. This procedure is repeated, and after processing for exclusive ORing all bits in the raw stream media data 40 with the key bit pattern 50 is completed, the finally generated and stored scrambled stream data 61 is output. (Step 108). The scrambled stream data 61 is sent to the user's client terminal 200 via a communication line by packet communication or the like, and is input to the descrambler 20.
[0047]
In the above-described encoding process, the key bit pattern generation device 30 is requested to the key bit pattern generation device 30 for each predetermined data amount unit of stream media data, for example, for MPEG data, for each predetermined number of packets, or at predetermined time intervals. Thus, the key bit pattern to be used is changed.
[0048]
Also, every time the key bit pattern is changed, identification information for uniquely identifying the key bit pattern used in the encoding process is embedded. If it is a packet, it is embedded in its header.
[0049]
Next, an operation of removing the scramble from the scrambled stream media data and extracting the raw stream media data in the descrambler 20 will be described with reference to the flowcharts of FIGS. 5, 6, and 8.
[0050]
The scrambled stream media data (scrambled stream data 61 output from the scrambler 10) input to the descrambler 20 in FIG. 1 uses a key bit pattern managed by the key bit pattern manager 21. Although the stream is decoded by the stream decoding unit 22, a detailed algorithm thereof will be described with reference to FIGS.
[0051]
The scrambled stream data 61 in FIGS. 5 and 6 is the encoded (scrambled) stream media data input to the key bit pattern management unit 21.
[0052]
The key bit pattern 80 for decrypting the scrambled stream data 61 (descramble the scramble) is generated exclusively by the key bit pattern generation device 30 and exclusive with the scrambled stream data 61 passed through the key bit pattern management unit 21. This is a key bit pattern for ORing. The key bit pattern 80 has the same bit pattern as the key bit pattern 50 used to generate the exclusive OR of the raw stream media data 40 by the scrambler 10 and generate the scrambled stream data 61.
[0053]
Upon receiving the input of the scrambled stream data 61 (FIG. 8, step 201), the descrambling device 20 determines whether a key bit pattern serving as a key for descrambling the scrambled stream data 61 exists in the key bit pattern management unit 21. It is confirmed whether or not it is (step 202). If the key bit pattern does not exist, the key bit pattern generation device 30 requests and receives the key bit pattern distribution from the key bit pattern generation device 30 based on the identification information of the key bit pattern embedded in the scrambled stream data 61 (step 203). ). That is, it is checked whether the currently used key bit pattern 80 exists in the key bit pattern management unit 21. The bit pattern management unit 21 holds the key bit pattern currently used for decryption until the key bit pattern is changed.
[0054]
When the key bit pattern 80 is held or when the key bit pattern 80 is acquired, the decryption processing is performed (descrambling) according to the following procedure (steps 204 to 208).
[0055]
First, an exclusive OR of data of 4 bits (“0100” of bit number 1 to bit number 4) from the head of the scrambled stream data 61 and the key bit pattern 80 is obtained (step 205).
[0056]
Until the descrambling of all the scrambled stream data 61 ends (step 206), the generated bit string “1001” is stored as the raw stream media data 91 (step 207).
[0057]
Subsequently, the exclusive OR of the data of the next 4 bits (“0111” of bit number 5 to bit number 8) in the scrambled stream data 61 and the key bit pattern 80 is calculated. The generated bit string “1010” is stored in connection with the continuation of the stored raw stream media data 91. This procedure is repeated, and after the process of taking the exclusive OR of all the bits in the scrambled stream data 61 with the key bit pattern 80 is completed, the raw stream media data 91 finally generated and stored is generated. It is output as stream media data (step 208).
[0058]
Between the scrambler 10 and the descrambler 20, it is prearranged to change the key bit pattern for each predetermined unit of data amount of stream media data. At predetermined time intervals, a new key bit pattern is obtained from the key bit pattern generation device 30 and subjected to encoding processing, and the descrambling device 20 embeds it in scrambled stream data for each predetermined unit data amount. If a new key bit pattern is acquired from the key bit pattern generation device 30 based on the identification information and the decoding process is performed, the encoding and the decoding can be synchronized.
[0059]
Next, another embodiment of the present invention will be described in detail with reference to the drawings.
[0060]
In the examples of FIGS. 3 to 6, encoding and decoding are performed on a certain amount of certain stream media data using one type of key bit pattern.
[0061]
However, a plurality of key bit patterns obtained from a plurality of key bit pattern generation devices 20 are used at the same time, a plurality of key bit patterns obtained at different timings are used at the same time, or one type of key bit pattern is generated by inversion. By using a plurality of key bit patterns at the same time, or by combining these methods, it is possible to perform encoding and decoding using a plurality of key bit patterns.
[0062]
By using the above method, the scrambling strength (confidentiality) can be increased as compared with the case where one type of key bit pattern is used. As a result, the present invention can be applied to more types of stream media data.
[0063]
FIG. 9 shows an example in which scrambling is performed using two key bit patterns. In this example, the key bit pattern 55 is generated by inverting the key bit pattern 50. This inversion of the key bit pattern is performed in the scrambler 10 and the descrambler 20. Thus, the scrambling device 10 and the descrambling device 20 can effectively perform the encoding process and the decoding process using two key bit patterns only by sharing one key bit pattern.
[0064]
In FIG. 9, scrambled stream data 303 is generated by performing an exclusive OR operation on the input raw stream media data 40 using key bit patterns 50 and 55 and encoding the resulting data. The key bit patterns 50 and 55 are applied in this order to the data after the bit number 9 of the raw stream media data 300 to obtain an exclusive OR, and finally the scrambled media data 303 that can be distributed on the network Generate
[0065]
FIG. 10 shows an example of descrambling using two key bit patterns 90 and 95. The key bit patterns 90 and 95 are the same key bit patterns as the key bit patterns 50 and 55 used for scrambling in FIG. 9, respectively. The raw stream media data 401 is generated by performing an exclusive OR operation on the scrambled stream data 303 using the key bit patterns 90 and 95 and decoding. The key bit patterns 90 and 95 are applied in this order to the data after the bit number 9 of the scrambled stream data 303 to obtain an exclusive OR, and the raw stream media data 401 is regenerated.
[0066]
The stream media data scramble broadcasting method of the present invention not only realizes the functions of each device as a constituent element in hardware but also executes the functions of each device described above and performs scrambling of the stream media data and scrambling of the scramble. This can be realized by loading a scramble processing program (application) for canceling into a memory of a computer processing unit (CPU) of a server of a broadcast service provider and a client terminal of a user and executing the program. That is, the functions of the scramble processing device and the descrambling device can be realized by software. The scramble processing program is stored in a magnetic disk, a semiconductor memory, or another recording medium, loaded from the recording medium into a computer processing unit, and controls the operation of the computer processing unit to realize the above-described functions.
[0067]
Although the present invention has been described with reference to the preferred embodiments and examples, the present invention is not necessarily limited to the above embodiments and examples, and various modifications may be made within the scope of the technical idea. Can be implemented.
[0068]
In the above embodiment, a case has been described where the descrambling device requests the key bit pattern generation device to generate a key bit pattern based on the identification information of the key bit pattern embedded in the stream data. However, instead of embedding the identification information of the key bit pattern in the stream data, the descrambling device may make the scramble device inquire of the identification information of the key bit pattern.
[0069]
【The invention's effect】
As described above, according to the stream media data scramble broadcasting method of the present invention, the following excellent effects can be obtained.
[0070]
High-speed encoding and decoding are performed on stream media data, and scramble broadcasting can be performed simply. Also, there is no need for special hardware for encoding and decoding, and broadcasting and reception of stream media data using encoding and decoding can be performed by a small device such as a mobile terminal or a home gateway in a home. Can be easily performed. Therefore, the cost of the scrambler and the descrambler can be reduced as compared with the conventional case, and the device can be widely spread. This makes it possible to start a full-scale broadcast service using packet communication.
[0071]
The reason is that the processing of the exclusive OR using the key bit pattern used for encoding and decoding in the present invention is implemented as a machine language level instruction in many CPUs, so that the processing by software is performed. But it can be done at high speed.
[0072]
The key strength in scrambling can be raised to a practical level by limiting the effective time of the key bit pattern and appropriately changing the pattern for the following reason.
[0073]
First, since it is more difficult to infer the original (raw) data in stream media data than character data, a method of simply applying a key from the head of the key space and checking whether or not the decryption has succeeded (A technique used for DES decryption) or a technique of collecting a large amount of encoded data and then examining the tendency (general decryption technique) to make it difficult to decrypt. In other words, practical key strength can be provided by encoding and decoding using exclusive OR processing using a key bit pattern.
[0074]
Second, in the case where the stream media data itself has a value correlated with time (for example, news distribution, etc.), data that has passed from the time of distribution loses its value as information, so that it is not possible to spend time for decoding. Therefore, in the case of stream media data such as news, even if the number of bits of the key bit pattern is small, practical key strength can be provided.
[0075]
Third, since the processing of the exclusive OR can be easily performed, even if the size of the key (bit pattern) is increased to a necessary and sufficient strength, the processing of the encoding and the decoding is not significantly affected. Therefore, sufficient key strength can be provided by increasing the number of bits of the key bit pattern.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a stream media data scramble broadcasting system according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating an overall configuration of a stream media data scramble broadcasting system according to the first embodiment of the present invention.
FIG. 3 is a diagram illustrating an algorithm when encoding using a key bit pattern according to the present invention.
FIG. 4 is a diagram illustrating an algorithm when encoding using a key bit pattern according to the present invention.
FIG. 5 is a diagram illustrating an algorithm when decoding is performed using a key bit pattern according to the present invention.
FIG. 6 is a diagram illustrating an algorithm when decoding is performed using the key bit pattern according to the present invention.
FIG. 7 is a flowchart illustrating an operation of a scrambler that performs encoding using a key bit pattern.
FIG. 8 is a flowchart illustrating an operation of a descrambling device that performs decryption using a key bit pattern.
FIG. 9 is a diagram illustrating an algorithm when encoding is performed using two key bit patterns.
FIG. 10 is a diagram illustrating an algorithm when decryption is performed using two key bit patterns.
[Explanation of symbols]
10 Scrambler
11 Key bit pattern management unit
12 Stream encoding unit
20 Descrambler
21 Key bit pattern management unit
22 Stream Decoding Unit
30 Key bit pattern generation device
40 raw stream media data
50 key bit pattern
61 Scramble stream data
80 key bit pattern
91 Raw stream media data

Claims (12)

In a stream media data scramble broadcasting system in which a distribution side encodes stream media data with an encryption key and distributes the stream media data via a communication line, and a reception side decodes the distributed stream media data with an encryption key,
A key bit pattern generation device that generates a key bit pattern of a predetermined number of bits as the encryption key,
The distribution side, at predetermined time intervals, performs decoding of the stream media data using a different key bit pattern generated from the key bit pattern generation device,
The scramble broadcasting system for stream media data, wherein the receiving side decodes the stream media data using the same key bit pattern as the distribution side. By changing the key bit pattern for each fixed data amount of stream media data, the distribution side and the reception side can set the key bit pattern used for encoding and decoding based on the fixed data amount. 2. The stream media data scramble broadcast system according to claim 1, wherein the stream media data is changed. The stream according to claim 1, wherein the encoding and decoding are performed by performing an exclusive OR operation on the input stream media data using the key bit pattern. Media data scramble broadcasting system. The stream media data scramble broadcasting system according to any one of claims 1 to 3, wherein the number of bits of the key bit pattern is increased or decreased according to the type of the stream media data. The encoding and decoding are performed using two bit patterns of the key bit pattern generated by the key bit pattern generation device and a bit pattern obtained by inverting the key bit pattern. The stream media data scramble broadcasting system according to any one of claims 1 to 4. At the time of encoding the stream media data, information for uniquely identifying the key bit pattern is embedded in the stream media data, and at the time of decoding the stream media data, the information of the embedded key bit pattern is embedded. The stream media data scramble broadcasting system according to any one of claims 1 to 5, wherein the key bit pattern used for decryption is obtained from the key bit pattern generation device based on information. In the stream media data scrambling broadcast system, the distribution side encodes the stream media data with an encryption key and distributes the stream media data via a communication line, and the reception side decodes the distributed stream media data with the encryption key. And a scramble processing program for performing decryption,
A key bit pattern generation device that generates a key bit pattern of a predetermined number of bits as the encryption key,
On the distribution side, at predetermined time intervals, decryption of the stream media data using different key bit patterns generated from a key bit pattern generation device that generates a key bit pattern of a predetermined number of bits as the encryption key Execute the function to perform
A scramble processing program, wherein the receiving side executes a function of decoding the stream media data using the same key bit pattern as that of the distribution side. By changing the key bit pattern for each fixed data amount of stream media data, the distribution side and the reception side can set the key bit pattern used for encoding and decoding based on the fixed data amount. 8. The non-transitory computer-readable storage medium according to claim 7, further comprising a changing function. 9. The apparatus according to claim 7, further comprising a function of performing the encoding and decoding by performing an exclusive OR operation on the input stream media data using the key bit pattern. The scramble processing program described. The storage medium according to any one of claims 7 to 9, further comprising a function of increasing or decreasing the number of bits of the key bit pattern according to the type of the stream media data. The encoding and decoding are performed using two bit patterns of the key bit pattern generated by the key bit pattern generation device and a bit pattern obtained by inverting the key bit pattern. The scramble processing program according to any one of claims 7 to 10. When encoding the stream media data, it has a function of embedding information for uniquely identifying the key bit pattern in the stream media data, and when decoding the stream media data, the embedded key The scramble processing program according to any one of claims 7 to 11, further comprising a function of acquiring the key bit pattern used for decryption from the key bit pattern generation device based on bit pattern information.

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