JP2004252050A - Device for authenticating digital audio data creator, reproducing device, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital audio data creator authentication device, a reproducing device, and a recording medium that inhibit data whose copyright is nonlegitimate from being reproduced to contribute to protection of copyright. <P>SOLUTION: On a transmission side 11, the individual division units of digital audio data (a) which are divided along the time axis are watermarked with creator characteristic information. On a reception side, on the other hand, watermark information is extracted and a verification part 15 verifies whether the watermark information is legitimate. A reproduction part 16 reproduces the digital audio information only when it is judged that the watermark information is legitimate. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a digital audio data creator authentication device, a reproducing device, and a recording medium, and more particularly to a digital audio data creator that provides a predetermined service on a receiving side only to digital audio data created by an authorized creator. The present invention relates to an audio data creator authentication device, a playback device, and a recording medium.
[0002]
[Prior art]
Digital audio has a remarkable distribution because it can easily make a copy with almost the same sound quality as the original sound. In addition, by using MPEG-audio Layer III (commonly known as MP3) or Advanced Audio Coding (commonly known as AAC) specified by ISO / IEC as a digital audio encoding method, audio having almost the same sound quality as the original sound is used. Data can be easily distributed through the Internet and the like.
[0003]
On the other hand, copyrights are often included in audio data, and due to the development of such technology, there are many cases where audio data with copyrights is illegally distributed. In order to determine whether or not such illegal data is circulating on the Internet, it is necessary to (1) add some unique information to the audio data or (2) embed the unique information, that is, a digital watermark. Is being done.
[0004]
[Problems to be solved by the invention]
However, in the method (1), since special information is added to the original data, there is a problem that a person who knows the format of the original data is easily attacked. Further, the method (2) is achieved by means for decoding digital audio data in which the digital watermark information is embedded and converting the digital audio data into an analog signal in order to check whether the digital watermark information is actually embedded. Most of them are. However, conventionally, there has been a problem that the processing capability of the means is not so high, and the detection accuracy of incorrect data is not good.
[0005]
The present invention has been made in view of the above-described conventional technology, and has as its object to provide a digital audio data creator authentication device, a reproducing device, and a recording medium that can accurately detect illegal audio data in which copyright or the like has been violated. To provide. Another object of the present invention is to provide a digital audio data creator authentication apparatus, a reproduction apparatus, and a recording medium that prohibit reproduction of data with illegal copyright and contribute to protection of copyright.
[0006]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention provides, on a transmission side, means for dividing digital audio data in a time axis direction, and for each of the division units, and in each specific part, the audio data creator. The first feature lies in that means for overwriting unique information is provided. According to this feature, it is possible to provide digital audio data including data that can specify an audio data creator.
[0007]
Also, the present invention provides a means for extracting the unique information written on the reproduction side from the specific portion, and determining whether the information extracted from the specific portion matches the unique information of the audio data creator. The second characteristic lies in that a means for judging whether or not, and a means for deciding that file reproduction of digital audio data is permitted when they match, and not permitted when they do not match. According to this feature, even a playback device having a low processing capability can play back only legitimate audio data created by a legitimate creator and prohibit playback of illegal audio data. Therefore, it is possible to provide a playback device that protects the copyright of the audio data creator, for example, a mobile phone.
[0008]
Further, according to the present invention, digital audio data overwritten with unique information of an audio data creator is stored for each division unit of digital audio data divided in a time axis direction, and in each specific portion. There is a third feature in providing a computer-readable recording medium. According to this feature, it is possible to provide a recording medium that stores audio data suitable for protecting the copyright of the audio data creator.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a schematic system according to an embodiment of the present invention.
[0010]
On the transmitting side 1, creator-specific information (x bits; x is a positive integer) is scrambled by a scrambling unit 2, and scrambled y-bit (y is a positive integer) data is output to a watermark insertion unit 4. . This scrambling can be performed, for example, by performing exclusive-OR processing (XOR) on the creator-specific information with a fixed bit string. This scrambling is not always necessary and may be omitted.
[0011]
On the other hand, the digital audio data a is input to the dividing unit 3 and divided in the time axis direction. This division is preferably performed every predetermined fixed time t seconds, for example, as shown in FIG. By this division, a plurality of frames having the configuration as shown in FIG. One frame is composed of a header, side information, and a data part as shown in the figure.
[0012]
The watermark insertion unit 4 embeds or overwrites the scrambled creator-specific information as watermark information in the data portion of the frame divided by the division unit 3. Since this embedding does not degrade the quality or sound quality of digital audio data, it is preferable to embed one bit per frame (see FIG. 2C). However, the embedding is not limited to this, and a plurality of bits may be embedded. . Further, it is preferable that the embedding is replaced with bit information in a specific portion. Note that the specific part in which the watermark information is to be embedded is determined in advance by the transmitting side 1 and the receiving side 11.
[0013]
It is preferable that the specific portion is a specific position on a grammar. The specific position can be determined based on amplitude information, a quantization coefficient, or amplitude information of a specific frequency of the audio data. For the amplitude information of the specific frequency, for example, the lowest order of the scale factor corresponding to the maximum frequency component among the scale factors of each frame in MPEG-1 Audio Layer-1, and for the quantization coefficient, for example, MPEG-1 Audio Of the samples assigned for each frequency in each frame in Layer-1, the lowest order of a sample of a specific frequency, and regarding the amplitude information, for example, the lowest order of each sample of uncompressed digital audio data is specified. Location. When the specific position is determined as described above, the influence on the audio data due to the embedding of the watermark information can be reduced as much as possible, and the deterioration of the audio data can be prevented as much as possible.
[0014]
The audio data into which the watermark information has been inserted as described above is output from the data output unit 5 as watermarked audio data d (see FIG. 2D). In the case where the watermark information is y bits and 1 bit is embedded per frame, when the number of audio data frames is y or more, the watermark information is not embedded in the frames after y. Become.
[0015]
The watermarked audio data d is transmitted wirelessly. Alternatively, it is stored in a computer-readable recording medium (CDROM or the like). The receiving side 11 (for example, a mobile device such as a mobile phone) receives the watermarked audio data d by the receiving unit 12. When reproducing the watermarked audio data d recorded on the recording medium, a recording medium reading unit is used instead of the receiving unit 12.
[0016]
The watermarked audio data d received by the receiving unit 12 is sent to the watermark extracting unit 13 and the reproducing unit 16. Since the watermark extracting unit 13 knows in advance in which part of the audio data the watermark data is inserted, the watermark extracting unit 13 correctly extracts the data of the specific part. The descrambling unit 14 descrambles the creator-specific information when the creator-specific information is inserted after being scrambled. The verification unit 15 determines whether or not the scrambled watermark information matches the creator-specific information. If it determines that the scrambled watermark information matches the creator-specific information, it determines that the audio data is copyrighted and valid audio data. , The reproduction in the reproduction unit 16 is permitted. Conversely, if it is determined that they do not match, it is determined that the audio data is illegal audio data that violates copyright, and reproduction is not permitted.
[0017]
When the inventor performed an experiment based on the present embodiment, the verification unit 15 on the receiving side can determine that the valid content in which the correct creator-specific information is embedded is 100% valid, and Unauthorized contents with embedded URLs were determined to be almost 100% illegal.
[0018]
It should be noted that, for a playback device having no function as in the present invention, that is, a playback device not having the watermark extraction unit 13, the verification unit 15, and the like, the quality of the audio data is slightly reduced, but the playback is always possible. . Therefore, when the present invention is implemented on the transmitting side, audio data can be reproduced even if a reproducing apparatus different from the method of the present invention is used on the receiving side, for example, a mobile phone of another maker, and there is no practical problem. . However, if the data is played back by a playback device of a different type, the creator will also play back audio data that is illegal.
[0019]
【The invention's effect】
As is apparent from the above description, according to the present invention, since only legitimate audio data created by a legitimate creator can be reproduced, it is possible to provide a device suitable for protecting copyright. Become. In addition, since it is only necessary to verify whether or not the creator's unique information is embedded at a predetermined position, it can be realized by a system having a data processing capacity not so high. Further, it is possible to provide a recording medium for storing audio data suitable for protecting copyright.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention.
FIG. 2 is a diagram for explaining a data structure created on a transmission side in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Transmission side, 3 ... Division part, 4 ... Watermark insertion part, 5 ... Data output part, 11 ... Receiving side, 12 ... Receiving part, 13 ... Watermark extraction Unit, 15: verification unit, 16: reproduction unit.

Claims (5)

Means for dividing digital audio data in the time axis direction;
Means for overwriting the specific information of the creator of the audio data for each of the division units and for each specific part. 2. The digital audio data creator authentication device according to claim 1,
The digital audio data creator authentication device, wherein the specific portion is a specific position on a grammar. The digital audio data creator authentication device according to claim 2,
The specific position in the grammar is a position where the degree of deterioration of the audio data is small, determined based on the amplitude information of the specific information of the audio data, the quantization coefficient of the audio data, or the amplitude information of the audio data. A digital audio data creator authentication device, characterized in that: Means for extracting, from the specific part, unique information written in digital audio data according to claim 1, 2, or 3;
Means for determining whether the information extracted from the specific part matches the unique information of the audio data creator,
Means for deciding that file reproduction of digital audio data is permitted when they match, and disabling the file reproduction when they do not match. A computer-readable recording in which digital audio data overwritten with specific information of an audio data creator is stored for each division unit of digital audio data divided in a time axis direction and in a specific portion thereof. Medium.

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