JP2002108395A - Digital music reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital music reproducing device which can prevent data having been decoded from being read out of a circuit. SOLUTION: This device is equipped with a circuit for decoding a code and a circuit for expanding compression in the same computing element and supplies data having been decoded to the circuit which expands the compression through an internal path of the computing element to prevent the data having been decoded from being read out of the circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encryption / decryption circuit for decrypting digital music data which has been compressed and encrypted, and an apparatus for decompressing the data decrypted by the encryption / decryption circuit to obtain the original digital data. The present invention relates to a digital music reproducing apparatus comprising a compression / decompression circuit for decompressing music data and reproducing digital music data decompressed by the compression / decompression circuit.

[0002]

2. Description of the Related Art There are various compression encoding methods for digital music data such as MP3 and TwinVQ. These compression-encoding methods enable music reproduction of sufficient quality even with a relatively narrow band and small capacity, and have led to a rapid spread of digital music reproduction devices for reproducing digital music data. The digital music reproducing apparatus includes a compression / decompression circuit that performs decoding corresponding to the compression encoding method used to compress and encode digital music data, expands the data, and restores the original digital data. In the digital music reproducing apparatus supporting various compression encoding methods, a programmable arithmetic element is often used as the compression / decompression circuit. A plurality of compression / decompression programs describing procedures for restoring original digital music data corresponding to a plurality of compression / encoding methods are recorded in a memory, and any one of the compression / decompression programs is loaded when necessary. The processing for restoring the original digital music data is performed by the arithmetic element. A problem in the digital music reproducing apparatus is a copyright on digital music data. Since the compression-coded digital music data has a small capacity, the time required for copying is short, and the compression coding method that is usually used is limited, so that reproduction of the copied data is easy. Of course, since the data is digital data, there is no sound quality degradation that occurs when an analog signal is copied. Therefore, there is a high possibility that the same music as the original music will be distributed by illegal copying. For this reason, there is a digital music reproducing apparatus which can reproduce digital music data which has been compressed and encrypted (compressed and encrypted) in advance. The digital music data that has been compressed and encrypted is decrypted in accordance with the cryptographic specifications, and the data obtained by compressing the data (data obtained by compressing the original digital music data) is expanded. The music data is restored. If the data has been compressed and encrypted in advance, the original digital music data cannot be obtained even if the data is copied.

[0003]

When digital music data that is not originally encrypted or digital music data that has been decrypted can be handled freely, illegal copying or distribution can be performed. It will be easier to do and will hinder the development of the music culture and, consequently, the digital music industry. However, in a digital music reproducing apparatus capable of reproducing digital music data that has been compressed and encrypted in advance, even if a programmable arithmetic element is used to decompress compressed data, decompression of compressed data and decryption of encryption are separate. This was performed using an arithmetic element. In other words, the data after the encryption and decryption flows on the data bus appearing in the electric circuit as it is. It is not impossible to read the data flowing on the data bus connecting the separate arithmetic elements, and there is a risk that the data after the encryption / decryption and thus the original digital music data will be illegally copied. The present invention has been made in view of such problems in the related art, and provides a digital music reproducing apparatus capable of preventing data after encryption and decryption from being read from a circuit. It is intended to do so.

[0004]

In order to achieve the above object, the present invention provides an encryption / decryption circuit for performing encryption / decryption on compressed and encrypted digital music data, and an encryption / decryption circuit using the encryption / decryption circuit. A digital music data reproducing apparatus for reproducing digital music data for reproducing the digital music data restored by the compression / decompression circuit, comprising: An encryption / decryption circuit and the compression / decompression circuit are provided in the same operation element, and data decrypted by the encryption / decryption circuit is supplied to the compression / decompression circuit through an internal bus of the operation element. It is configured as a characteristic digital music playback device. In the digital music reproducing apparatus according to the present invention, there is provided an encryption / decryption circuit for performing encryption / decryption of the compressed and encrypted digital music data; A compression / decompression circuit for restoring data is provided in the same operation element, and the data decrypted by the encryption / decryption circuit is supplied to the compression / decompression circuit through an internal bus of the operation element. For this reason, the data decrypted by the decryption circuit cannot be directly obtained from the bus outside the arithmetic element, and the data after the decryption is read from the circuit cannot be obtained. Can be prevented. However, even if the decrypted data cannot be obtained from the bus outside the arithmetic element, the decrypted data used for performing the decryption may be obtained from the bus external to the arithmetic element. If possible, the original digital music data may be restored from the compressed and encrypted digital music data using the decrypted data. Accordingly, in the digital music reproducing apparatus, for example, an encryption / decryption data recording memory for recording encryption / decryption data used by the encryption / decryption circuit to perform encryption / decryption on the compressed and encrypted digital music data is also provided by the arithmetic operation. The decryption data may be provided in an element and supplied to the decryption circuit from the decryption data recording memory through the internal bus of the arithmetic element. In this case, the decryption data used for performing the decryption cannot be obtained from the bus outside the arithmetic element, so that the copy of the original digital music data can be more firmly prevented.

The digital music data decompressed by the compression / decompression circuit has a large capacity and takes a long time to be copied, but once copied, almost the same original data can be obtained. There is no. Therefore, in the digital music player,
For example, a digital-to-analog converter for converting the digital music data restored by the compression / decompression circuit into an analog signal is also provided in the arithmetic element, and the digital music data restored by the compression / decompression circuit is stored in an internal bus of the arithmetic element. May be supplied to the digital-to-analog converter. In this case, the digital music data decompressed by the compression / decompression circuit cannot be obtained from a bus outside the arithmetic element, and illegal duplication can be made more difficult. In the digital music reproducing apparatus, a plurality of compression / decompression programs used by the compression / decompression circuit may be prepared in order to support a plurality of compression / encoding methods. Since it is expensive, a non-volatile, relatively low-speed memory is used to reduce the cost. However, if the compression / decompression program is supplied to the compression / decompression circuit from a nonvolatile memory having a relatively low speed, the processing speed is reduced. Therefore, in the digital music reproducing apparatus, for example, a volatile compression / decompression program for recording a partial compression / decompression program recorded in a nonvolatile compression / decompression program recording memory for recording a compression / decompression program used by the compression / decompression circuit. A temporary recording memory may be provided in the arithmetic element, and the part of the compression / decompression program may be supplied from the compression / decompression program temporary recording memory to the compression / decompression circuit. In this case, it is sufficient that the compression / decompression program temporary recording memory has enough capacity to record a part of the compression / decompression program stored in the compression / decompression program recording memory. Since a relatively high-speed volatile compression / decompression program is supplied from a temporary recording memory, high-speed processing can be realized while suppressing costs.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
The following embodiments are specific examples of the present invention and do not limit the technical scope of the present invention. FIG. 1 is a diagram showing a schematic configuration of a digital music reproducing apparatus according to an embodiment of the present invention. As shown in FIG. 1, a digital music reproducing apparatus according to an embodiment of the present invention includes a digital music data recording memory 101, an arithmetic element 102, a compression / decompression program recording memory 103,
It comprises an A converter 104, an analog circuit 105, and the like. The digital music data recording memory 101 is a memory for storing digital music data that has been compressed and encrypted, and is connected to the arithmetic element 102. The arithmetic element 102 restores the digital music data from the digital music data recording memory 101 to the original digital music data before being compressed and encrypted, and is connected to the D / A converter 104. I have. The compression / decompression program recording memory 103 is connected to the outside of the arithmetic element 102, and supplies a compression / decompression program for performing decoding corresponding to the compression coding method in which the digital music data is compression-coded to the calculation element 102. The D / A converter 104 converts the digital music data supplied from the arithmetic element 102 into an analog signal, and is connected to the analog circuit 105. Analog circuit 105
Connects the D / A converter 104 and a speaker, performs processing such as amplification if necessary, and then performs D / A conversion 104
The analog signal from is input to the speaker.

A main part of the digital music reproducing apparatus according to the embodiment of the present invention is the arithmetic element 102 in each of the above-described configurations. FIG. 1 also shows the internal configuration of the arithmetic element 102. As shown in FIG.
The data input circuit 11, the decryption circuit 12,
It includes a compression / decompression circuit 13, a data output circuit, and a decryption data recording memory 21. The data input circuit 11 is connected to the digital music data recording memory 101 and is an interface for inputting digital music data compressed and encrypted from the digital music data recording memory 101 to the arithmetic element 102. The encryption / decryption circuit 12 is a circuit for decoding the encryption of the compressed and encrypted digital music data input from the data input circuit 11 using the encryption / decryption data recorded in the encryption / decryption data recording memory 21. is there. The compression / decompression circuit 13 uses the compression / decompression program recorded in the compression / decompression program recording memory 103 to decompress the data decrypted by the decryption circuit 12 to recover the original digital music data before compression. Circuit. The data output circuit 11 is an interface for outputting the digital music data obtained by the compression / decompression circuit 13 to the D / A converter 104.
The decryption data recording memory 21 is a memory for recording decryption data for decryption, and supplies the decryption data to the decryption circuit 12.
For example, in the case of using the DES common key encryption method, the encryption / decryption data recording memory 21 records parameter data for DES encryption and a common key that is to be kept secret common to the encryption processing side. The components in the arithmetic element 102 as described above are connected by an internal bus (in FIG. 1, indicated by an arrow in the arithmetic element 102 for the sake of convenience), and what is obtained from a connection path outside the arithmetic element 102 is , Data input to the data input circuit 11, data output from the data output circuit 14, and a compression / decompression program. Since the data output from the encryption / decryption circuit 12 is compressed but not encrypted, and the compression encoding method that is often used is limited, it is difficult to restore the original digital music data. It is simple and the data capacity is relatively small, so it is easy to copy. Such data also passes only through the internal bus of the arithmetic element 102 and is hidden from the outside. Also, the decrypted data recorded in the decrypted data recording memory 21 passes only through the internal bus and is hidden from the outside. If the decrypted data in the decrypted data recording memory 21 is illegally obtained, the original digital music data can be easily restored from the compressed digital music data even if only the compressed digital music data is obtained. However, such a situation is also prevented by hiding the decrypted data from the outside. As described above, in the digital music reproducing apparatus according to the embodiment of the present invention, the decryption circuit and the compression / decompression circuit are provided in the same arithmetic element, and the decryption circuit is decrypted by the decryption circuit. Since the data is supplied to the compression / decompression circuit through the internal bus of the arithmetic element, it is possible to prevent the decrypted data from being read from the circuit. Further, the decryption data storage memory is also provided in the arithmetic element, and the decryption data is supplied from the decryption data storage memory to the decryption circuit through the internal bus of the arithmetic element. The decrypted data required to restore the original digital music data from the compressed and encrypted data can also be hidden from the outside.

[0008]

In the above embodiment, the compression / decompression program was directly supplied to the compression / decompression circuit 13 from a compression / decompression program recording memory 103 arranged outside the arithmetic element 102. For example, as shown in FIG. A volatile compression / decompression program temporary recording memory 31 for temporarily recording the compression / decompression program is provided in the arithmetic element 102, and a required one of the compression / decompression programs stored in the compression / decompression program recording memory 103 is used. The compression / decompression program may be stored in the compression / decompression program temporary recording memory 31, and the compression / decompression program may be supplied to the compression / decompression circuit 13 through the compression / decompression program temporary recording memory 31. In order to perform higher-speed processing, it is preferable to read the compression / decompression program from a high-speed memory. However, a volatile high-speed memory is expensive, and the capacity required to store many of the compression / decompression programs is reduced. Attempting to secure it makes it difficult to keep costs down. On the other hand, since a nonvolatile low-speed memory is relatively inexpensive, the cost can be suppressed even if the capacity of the compression / decompression program recording memory 103 is increased. Therefore, the capacity of storing one or a part of the compression / decompression program stored in the compression / decompression program recording memory 103 is changed to the compression / decompression program temporary recording memory 3.
1, and the compression / decompression program used by the compression / decompression circuit 13 is supplied from the compression / decompression program temporary recording memory 31. Compression / decompression program recording memory 10
If the capacity of No. 3 can store a small number of compression / decompression programs, the increase in cost is not so large, and high-speed processing can be realized while suppressing the cost. Further, in the above embodiment, D / D
The A / D converter 104 is provided, but as shown in FIG. 3, for example, the D / A converter 104 is also provided inside the arithmetic element 102, and digital music data output from the data output circuit 14 is transmitted to the internal bus of the arithmetic element 102. May be supplied to the D / A converter 41. Data output circuit 1
The digital music data output from 4 has a large capacity and takes a long time to be copied, but once copied, almost the same data as the original is obtained. Therefore, by supplying the digital music data output from the data output circuit 14 to the D / A converter 41 through the internal bus of the arithmetic element 102, the digital music data is also concealed. This can make unauthorized duplication more difficult.

[0009]

As described above, according to the digital music reproducing apparatus of the present invention, an encryption / decryption circuit for performing encryption / decryption of compressed and encrypted digital music data, and encryption / decryption by the encryption / decryption circuit. A compression / decompression circuit for decompressing the decoded data and restoring the original digital music data is provided in the same arithmetic element, and the data decrypted by the encryption / decryption circuit is transferred to the internal bus of the arithmetic element. Since the data is supplied to the compression / decompression circuit through the circuit, it is possible to prevent the decrypted data from being read from the circuit. In the digital music reproducing apparatus, for example, an encryption / decryption data recording memory for recording encryption / decryption data used by the encryption / decryption circuit to perform encryption / decryption on the compressed / encrypted digital music data is also included in the arithmetic operation. If the decryption data is provided in the element and supplied to the decryption circuit from the decryption data recording memory through the internal bus of the arithmetic element, the decryption data used for decryption is also provided. The digital music data cannot be obtained from a bus outside the arithmetic element, and the duplication of the original digital music data can be prevented more firmly. Further, in the digital music reproducing apparatus, for example, a digital-analog converter for converting the digital music data decompressed by the compression / decompression circuit into an analog signal is provided in the arithmetic element, and the digital signal decompressed by the compression / decompression circuit is provided. If music data is supplied to the digital-to-analog converter through the internal bus of the arithmetic element, the digital music data decompressed by the compression / decompression circuit cannot be obtained from a bus external to the arithmetic element. Duplication can be made more difficult. Further, in the digital music reproducing apparatus, for example, a volatile compression / decompression program for recording a partial compression / decompression program recorded in a nonvolatile compression / decompression program recording memory for recording a compression / decompression program used by the compression / decompression circuit If a temporary recording memory is provided in the arithmetic element, and a part of the compression / decompression program is supplied from the compression / decompression program temporary recording memory to the compression / decompression circuit, high-speed processing can be realized while suppressing costs.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a digital music playback device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a digital music reproducing apparatus according to one embodiment of the present invention.

FIG. 3 is a diagram showing a schematic configuration of a digital music playback device according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 12 encryption / decryption circuit 13 compression / decompression circuit 21 encryption / decryption data recording memory 31 compression / decompression program temporary recording memory 102 arithmetic element 104 D / A converter

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[Procedure amendment]

[Submission date] August 3, 2001 (2001.8.3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004]

In order to achieve the above object, the present invention provides an encryption / decryption circuit for performing encryption / decryption on compressed and encrypted digital music data, and an encryption / decryption circuit using the encryption / decryption circuit. A digital music data reproducing apparatus for reproducing digital music data for reproducing the digital music data restored by the compression / decompression circuit, comprising: An encryption / decryption circuit; the compression / decompression circuit;
Non-volatile compression / decompression program that records compression / decompression programs
Some compression / decompression programs recorded in RAM recording memory
Volatile compression / decompression program for temporary recording memory
Preparative provided within the same computing device, the encrypted data decoded by said decrypting circuit is supplied to the decompression circuit through the internal bus of the computing device, wherein a portion of the decompression
Is the program a temporary storage for the compression / decompression program?
The digital music reproducing device is supplied to the compression / decompression circuit . In the digital music reproducing apparatus according to the present invention, there is provided an encryption / decryption circuit for performing encryption / decryption of the compressed and encrypted digital music data; A compression / decompression circuit for restoring data is provided in the same operation element, and the data decrypted by the encryption / decryption circuit is supplied to the compression / decompression circuit through an internal bus of the operation element. For this reason, the data decrypted by the decryption circuit cannot be directly obtained from the bus outside the arithmetic element, and the data after the decryption is read from the circuit cannot be obtained. Can be prevented . Ma
In the digital music reproducing apparatus, a plurality of compression codes
Use of the compression / decompression circuit to support
In some cases, multiple compression / decompression programs are prepared.
Since relatively fast memories are expensive,
If you try to suppress it, use non-volatile relatively slow memory.
Will be used. However, the relatively low non-volatility
The compression and decompression program from the fast memory
When supplied to the circuit, the processing speed is reduced. However
According to the above invention, the compression / decompression program temporary recording method
Memory stores the data in the compression / decompression program recording memory.
Space for recording some of the decompressed programs
It is sufficient to secure it, and some of the above-mentioned compression / decompression programs
Is a relatively fast volatile decompression program temporary recording
It is supplied from memory, so it is fast while keeping costs down.
Processing can be realized. However, even if the decrypted data cannot be obtained from the bus outside the arithmetic element, the decrypted data used for performing the decryption can be obtained from the bus external to the arithmetic element. If possible, the original digital music data may be restored from the compressed and encrypted digital music data using the decrypted data. Therefore, in the digital music reproducing apparatus, for example, an encryption / decryption data recording memory for recording encryption / decryption data used by the encryption / decryption circuit to perform encryption / decryption on the compressed / encrypted digital music data also includes the arithmetic operation. The decryption data may be provided in an element and supplied to the decryption circuit from the decryption data recording memory through the internal bus of the arithmetic element. In this case, the decrypted data used for performing the decryption cannot be obtained from the bus outside the arithmetic element, so that the copy of the original digital music data can be prevented more firmly.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

The digital music data decompressed by the compression / decompression circuit has a large capacity and takes a long time to be copied, but once copied, almost the same original data can be obtained. There is no. Therefore, in the digital music player,
For example, a digital-to-analog converter for converting the digital music data restored by the compression / decompression circuit into an analog signal is also provided in the arithmetic element, and the digital music data restored by the compression / decompression circuit is stored in an internal bus of the arithmetic element. May be supplied to the digital-to-analog converter. In this case, the digital music data decompressed by the compression / decompression circuit cannot be obtained from a bus outside the arithmetic element, and illegal duplication can be made more difficult .

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Toshiaki Shimoda 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo F-term in Kobe Steel Research Institute Kobe Research Institute 5D044 AB05 BC03 FG10 FG18 GK07 HL08 HL09 5D045 DA20 5J064 AA00 BC01 BC02 BC07 BD03

Claims (4)

[Claims] An encryption / decryption circuit for decrypting digital music data which has been compressed and encrypted, and a compression for expanding data decrypted by the encryption / decryption circuit and restoring the original digital music data. A digital music reproducing apparatus for reproducing digital music data decompressed by the compression / decompression circuit, wherein the encryption / decryption circuit and the compression / decompression circuit are provided in the same arithmetic element; A digital music reproducing apparatus characterized in that data decrypted by a circuit is supplied to the compression / decompression circuit through an internal bus of the arithmetic element. And a decryption data recording memory for recording decryption data used by the decryption circuit for performing decryption on the compressed and encrypted digital music data is provided in the arithmetic element. 2. The digital music reproducing apparatus according to claim 1, wherein said decryption data is supplied from said decryption data recording memory to said decryption circuit through an internal bus of said arithmetic element. 3. A digital-to-analog converter for converting the digital music data decompressed by the compression / decompression circuit into an analog signal is provided in the arithmetic element, and the digital music data decompressed by the compression / decompression circuit is subjected to the arithmetic operation. 3. The digital music reproducing apparatus according to claim 1, wherein said digital music converter is supplied to said digital-to-analog converter through an internal bus of said element. 4. A volatile compression / decompression program temporary recording memory for recording a partial compression / decompression program recorded in a nonvolatile compression / decompression program recording memory for recording a compression / decompression program used by the compression / decompression circuit. 2. The digital music reproducing apparatus according to claim 1, wherein said part of the compression / decompression program is provided in an arithmetic element and supplied to said compression / decompression circuit from said compression / decompression program temporary recording memory.