JP2001125484A - Device and method for embedding watermark data, transmission method, recording medium and watermark - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize the deterioration of contents data when embedding a watermark data in the contents data, and also to hardly remove only the watermark data embedded in the contents data by the third party. SOLUTION: An error detection code is added to a watermark data, and further, a watermark data obtained by ciphering the watermark data, to which the error detection signal has been added based on an inputted password, in embedded in contents data by selecting one of plural selecting means different in intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In a system for distributing digitized content data, in order to prevent illegal copying and resale of the content, information on the creator such as the copyright of the content is watermarked (digital wa).
watermark data embedding device to record as termark)
The present invention relates to a watermark data embedding method, a transmission method for transmitting data in which watermark data is embedded, a recording medium in which watermark data is embedded, and a watermark data reading method.

[0002]

2. Description of the Related Art With the advance of digital technology, various works such as movies, music, and photographs are distributed as digital data. These digital data are digitized image data and audio data such as still images and moving images, and content data such as MIDI data. The digital data is recorded on a recording medium such as a CD-ROM and sold, or is distributed by a network such as the Internet. Have been sent and received.

[0003] Such digital data is characterized in that a complete copy can be easily and easily made in large quantities. This is because a user who has obtained the digital data illegally makes a copy equivalent to the original and re-creates it. It shows the possibility of distribution and resale. As a result, the price to be paid to the creator of the digital data or a person who has been legally entrusted to sell the digital data is not paid, and the copyright may be infringed.

[0004] The problem of the copyright of such digital data is becoming more serious, and in recent years, digital watermarking technology has been spotlighted as a technology for preventing this problem.

According to this technique, in order to protect the rights of a data creator and a provider, information about the creator and the user is inserted into the data in a form in which the user cannot distinguish it, and the copyright holder is identified. It is for confirming or, in the case of unauthorized use, identifying the user.

[0006] The conditions necessary for this digital watermark include:
Embedding the watermark data so that if the watermark data is forcibly removed, the content data itself will be broken (watermark information indicating the copyright remains in the content data), and where the watermark information is embedded in the content data Is difficult to understand, and even if the watermark data is embedded, the content data may be kept in the original state and quality.

A digital watermarking technique satisfying these conditions is to embed watermark data in a part (redundant part) that is not important for human perception in content data such as image data and audio data, thereby reducing the total data amount. It is considered to embed watermark data without changing.

[0008] Further, a method has been considered in which attention is paid to specific data in the content data, and a part of the specific data is replaced with other data to form a digital watermark.

[0009]

However, when embedding the watermark data in the content data, it is difficult to determine at what strength the watermark data should be embedded. This has the problem that the greater the embedding strength of the watermark data, the greater the effect on the content data, and consequently the greater the degradation of the content data. However, if the embedding strength of the watermark data is too weak, there is a problem that it is relatively easy for a third party to intentionally remove the watermark data.

[0010]

SUMMARY OF THE INVENTION Therefore, the present invention provides an error detection code adding means 1 for adding an error detection code to watermark data embedded in content data, and an error detection code adding means based on an input password. An encryption unit 2 for encrypting the added watermark data, a plurality of watermark data embedding units 4 having different embedding strengths for embedding the encrypted watermark data in the content data, A watermark data embedding apparatus, comprising: an embedding means selecting means 3 for selecting an embedding means 4 for embedding data from the plurality of watermark data embedding means 4.

A step of adding an error detection code to watermark data to be embedded in the content data; a step of inputting a password; and a step of encrypting the watermark data to which the error detection code is added based on the password. Selecting a embedment unit for actually embedding watermark data from a plurality of watermark data embedding units each having a different embedding strength for embedding the encrypted watermark data in the content data; There is provided a watermark data embedding method comprising the step of embedding the encrypted watermark data by a selected embedding means.

Further, an error detection code is added to the watermark data to be embedded in the content data, and the watermark data to which the error detection code is added is encrypted based on the input password. Embedment means for actually embedding watermark data is selected from a plurality of watermark data embedding means having different embedding strengths for embedding watermarked data, and the encrypted watermark data is selected by the selected embedding means. And transmitting the content data in which the watermark data obtained by embedding the content data is embedded.

Still further, an error detection code is added to the watermark data embedded in the content data, the watermark data to which the error detection code is added is encrypted based on the input password, and the encryption is performed on the content data. The embedding means for actually embedding the watermark data is selected from a plurality of watermark data embedding means each having a different embedding strength for embedding the watermark data thus obtained, and the encrypted watermark is selected by the selected embedding means. A recording medium 100 characterized by recording the content data in which watermark data obtained by embedding data is embedded.

Further, an error detection code is added to the watermark data to be embedded in the content data, and the watermark data to which the error detection code is added is encrypted based on the input password. In order to embed watermark data, a plurality of embedding means having different embedding strengths are respectively selected from a plurality of embedding means, and a plurality of embedding means obtained by embedding watermark data obtained by embedding the watermark data obtained by different embedding methods are provided. The watermark data is read from the content data in which the watermark data is embedded by all reading means corresponding to the embedding means, and the read watermark data is decrypted using the password, and the validity of the result is checked. Detecting the error In sure to provide a watermark data reading method characterized by what has been confirmed as true watermark data to be valid.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a watermark data embedding apparatus, a watermark data embedding method, a transmission method for transmitting data with embedded watermark data, a recording medium with embedded watermark data, and a watermark data reading method according to the present invention will be described with reference to the drawings. This will be described with reference to FIG.

FIG. 1 is a block diagram showing the concept of a watermark data embedding device according to the present invention. According to the figure, after the watermark data is added with the error detection code by the error detection code adding means 1, it is sent to the encryption means 2, where the encryption data is encrypted based on the password input by the user. You.

The watermark data added with the error detection code and encrypted is embedded in the content data by N watermark embedding encoders 4 having different strengths. The encoder 4 employs watermark embedding methods having different strengths, and the watermark data is embedded arbitrarily or randomly selected from the encoder 4 by the selector 3.

Here, an example of the above-described watermark embedding method of different strength will be described based on a case where a watermark is embedded in 16-bit quantized sample data. Four encoders 4 having different watermark embedding strengths (N =
4), the watermark embedding strength of the first encoder is the weakest, the watermark embedding strength of the second encoder, the watermark embedding strength of the third encoder increases in order, and the fourth embedding strength increases. Assuming that the watermark embedding strength of the encoder is the strongest, when the original content data is the following 16-bit sample data, the sample data in which the watermark data is embedded by the first encoder is as follows. Become. 1001100100011110 (when the embedded bit is 0) 1001100100011111 (when the embedded bit is 1) Further, the sample data in which the watermark data is embedded by the second encoder is as follows. 1001100100011100 (when the embedded bit is 0) 1001100100011110 (when the embedded bit is 1) Further, the sample data in which the watermark data is embedded by the third encoder is as follows. 10011000100011000 (when the embedded bit is 0) 1001100100011100 (when the embedded bit is 1) Further, the sample data in which the watermark data is embedded by the fourth encoder is as follows. 10011001000100000 (when the embedded bit is 0) 1001100100010001000 (when the embedded bit is 1) The watermark data is embedded in the content data by the encoder 4 selected by the selector 3 from among these encoders 4. At this time, the influence on the original content data increases as the watermark embedding strength increases. When a third party attacks the content data in which the watermark data is embedded to remove the watermark data, for example, the content data in which the watermark data is embedded by the first encoder is used. It is possible to remove the watermark data by attacking the lower 1 bit (when focusing only on the strength), but attack the lower 4 bits for the content data in which the watermark data is embedded by the fourth encoder. Otherwise, the watermark data cannot be removed. Then, an attack must be performed assuming a case where the watermark strength is the strongest, and the quality of the content data after the attack is greatly degraded, so that it may not be possible to fulfill the role as the content data.

Therefore, an encoder used for embedding watermark data is selected according to the importance of the content data and the like, and the embedding strength of the watermark data is arbitrarily set or randomly selected, so that a third party in the content data can be selected. It is possible to efficiently avoid attacks from the Internet.

In this embodiment, the embedding strength of the watermark data is increased as the higher-order bits of the content data are embedded, and the lower bits are treated as noise components. Is, of course, not limited to this.

As described above, the converted content data in which the watermark data is embedded is stored in the recording medium 1 as necessary.
00 or recorded in the storage unit 101 connected to the transmission unit 102 for transmission to each terminal or the like. Thus, it becomes possible to distribute the content data in which the watermark data is embedded by the recording medium 100, and to distribute the content data in which the watermark data is embedded by the transmission unit 102.

In order to read the watermark data from the converted content data in which the watermark data is embedded, the watermark data reading device shown in FIG. 2 is used. According to the figure, the converted content data is read out according to all the watermark data reading methods defined by the N decoders 5. The read temporary watermark data is decrypted by the decrypting means 6 based on the password input by the user. The decoded temporary watermark data is sent to the error detection unit 7 using the error detection code added when embedding the watermark.
The temporary watermark data evaluated as valid and regarded as valid is selected by the data selecting means 8 and the true watermark data is output as embedded content data.

[0023]

As described above, according to the watermark data embedding apparatus, the watermark data embedding method, the recording medium, the transmission method, and the watermark data reading method according to the present invention, an attack on the watermark data by a third party is assumed. If you do not know the password for encrypting the watermark data, you cannot determine how strong the watermark data is embedded in the content data. Attack on the content data, and the quality of the content data after the attack is greatly deteriorated. That is, unless the password is known, there is an effect that only the watermark data cannot be efficiently removed from the content data.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the concept of a watermark information embedding device according to the present invention.

FIG. 2 is a block diagram illustrating the concept of a watermark information reading device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Error detection code addition means 2 Encryption means 3 Selector 4 Encoder 5 Decoder 6 Decryption means 7 Validity check means 8 Data selection means 100 Recording medium 101 Storage means 102 Transmission means

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Claims (5)

[Claims] 1. An error detection code adding means for adding an error detection code to watermark data embedded in content data, and an encryption for encrypting the watermark data to which the error detection code has been added based on an input password. Means, a plurality of watermark data embedding means each having a different embedding strength for embedding the encrypted watermark data in the content data, and an embedding means for actually embedding the watermark data in the plurality of watermark data. An embedding means selecting means for selecting from embedding means. 2. A step of adding an error detection code to watermark data embedded in content data; a step of inputting a password; and a step of encrypting the watermark data to which the error detection code has been added based on the password. Selecting an embedding unit for actually embedding watermark data from a plurality of watermark data embedding units having different embedding strengths for embedding the encrypted watermark data in the content data, A watermark data embedding method comprising the step of embedding the encrypted watermark data by the selected embedding means. 3. An error detection code is added to watermark data to be embedded in content data, and the watermark data to which the error detection code is added is encrypted based on an input password. Embedment means for actually embedding watermark data is selected from a plurality of watermark data embedding means having different embedding strengths for embedding watermarked data, and the encrypted watermark data is selected by the selected embedding means. And transmitting the content data in which the watermark data obtained by embedding is embedded. 4. An apparatus for adding an error detection code to watermark data to be embedded in content data, encrypting the watermark data to which the error detection code has been added based on an input password, and encrypting the content data. Embedment means for actually embedding watermark data is selected from a plurality of watermark data embedding means having different embedding strengths for embedding watermarked data, and the encrypted watermark data is selected by the selected embedding means. A recording medium for recording the content data in which watermark data obtained by embedding the content data is embedded. 5. An apparatus for adding an error detection code to watermark data to be embedded in content data, encrypting the watermark data to which the error detection code has been added based on an input password, and encrypting the content data. In order to embed watermark data, a plurality of embedding means having different embedding strengths are obtained by selecting and embedding one embedding means from a plurality of embedding means having different embedding strengths. The watermark data is read from the content data in which the watermark data is embedded by all reading means corresponding to the embedding means, and the read watermark data is decrypted using the password, and the validity of the result is checked. By detecting the error A method of reading watermark data, wherein the method confirms and confirms that the data is valid as true watermark data.