KR100346564B1 - Method and apparatus for information hiding using random sequence and hadamard matrix - Google Patents

Abstract

The present invention relates to a method and method for concealing multiple pieces of information using a random sequence and a Hadamard matrix, and a method and method for concealing multiple pieces of information using a random sequence and a Hadamard matrix for efficiently extracting hidden information. According to the present invention, a new spreading code is generated by multiplying an orthogonal Hadamard matrix and a random sequence, multiplying a new spreading code by an information signal to be concealed, and spreading a band, and then adding a predetermined video signal to a spread spectrum information signal. Insert the process to output the concealed signal of the information signal, and extract the original information signal from the concealed signal output by the spreading code of the same type as the new spreading code, and then set it to 1 if the extracted information signal is more than a predetermined value. If the extracted information signal is equal to or less than a predetermined value, the threshold processing is set to zero. The present invention also provides a Hadamard matrix having an orthogonality, a first multiplier for generating a spreading code by a Hadamard matrix and a random sequence, a second multiplier for spreading a band of an information signal to be concealed by the spreading code, and a constant image. An adder for concealing the information signal spread by the signal, a third multiplier for generating a Hadamard matrix having the same form as a Hadamard matrix and a random sequence, and a spreading code based on the random sequence, and concealed by a spreading code of the third multiplier And a fourth multiplier for extracting the original information signal from the extracted information signal, and a threshold processing means for setting the value to 1 when the extracted original information signal is greater than or equal to a predetermined value and to 0 when less than or equal to a predetermined value. Therefore, a new spreading code is generated using a Hadamard matrix and a random sequence having orthogonality, and the multiple spreading information is concealed by the new spreading code. It can prevent the occurrence of accurate extraction of multiple concealed information, as well as concealed information about the image compression algorithm and Gaussian noise that can be generated on the communication path when the concealed information signal is transmitted through the network. Accurate extraction of can be performed.

Description

Multiple information concealment apparatus and method using random sequence and Hadamard matrix {METHOD AND APPARATUS FOR INFORMATION HIDING USING RANDOM SEQUENCE AND HADAMARD MATRIX}

The present invention relates to an apparatus and method for concealing multiple information, and more particularly, to an apparatus and method for concealing multiple information using a random sequence and a Hadamard matrix.

Recently, with the rapid development of computer network and multimedia related technologies, the demand for digitized voice and video media is also rapidly increasing.

As such services for digital media have evolved into more comprehensive multimedia services in the information society of the 21st century, the use of digital media using communication networks such as the Internet is expected to increase beyond the demand.

When transmitting voice or video information through a digital medium using a communication network such as the Internet, the information is concealed and transmitted so that the information is not exposed to the outside due to the importance of the information, and the receiver of the transmitted information accurately hides the information. Research into a method for receiving information transmitted by recovering without error, that is, digital information hiding technology, has been actively conducted.

The characteristics under consideration in the various digital information concealment technologies currently under study can be divided into three categories.

That is, the capacity of information that can be extracted after being concealed in the digital image, the imperceptibility of the information that is concealed, and the robustness that cannot easily remove the information concealed by accident or by other intentions. (robustness).

However, since the characteristics such as unrecognition and robustness considered in the above-described digital information concealment technology are in conflict with each other, it is very difficult to realize the information concealment technology that satisfies all the characteristics at the same time.

For example, captioning, which is one of digital information concealment techniques, is a technique for extracting cover images that are combined to conceal information. Therefore, the amount of information to be concealed is important, and copyright protection is illegal in copyright protection. More robustness to removal is important. And, in secure communication, the most unconsciousness to prevent leakage of information to be transmitted to the outside is considered most.

However, the ideal information concealment technology should be able to be used universally for all purposes. In this respect, the information concealment technology has a large amount of information to be concealed, illegal users cannot recognize concealed information, It must have high robustness to removal.

Representative information concealment techniques for digital media published to date include spread spectrum techniques which have been used for military purposes in the past, such as frequency hopping and direct sequence (DS). This makes it difficult for an illegal user to extract concealed information by spreading the energy of the information by a spreading code having a noise characteristic of the original information to be concealed. In this case, a random sequence is generally used as a spreading code having a noise characteristic.

The information concealment technique by the spread spectrum technique described above is as follows.

First, the frequency hopping spreading method of the spread spectrum technique converts a carrier frequency of a signal to be spread spectrum by temporally converting a narrowband signal into a time average by temporally converting the carrier frequency of the information signal according to a predetermined pattern within a range known to the transmitting and receiving sides of the information signal. Convert to a wideband signal. That is, the frequency band is spread by irregularly changing the frequency of the carrier modulated with the data sequence by the frequency synthesizer.

At this time, the modulation operation on the transmitting side is called frequency hopping, and the frequency band is reduced by hopping and reducing the carrier frequency in a manner opposite to that of the transmitting side on the receiving side.

In addition, the DS method of the spread spectrum scheme is composed of +1 and -1 having a much wider bandwidth characteristic than the original information, and obtains the spreading information by spreading the spreading code, for example, by multiplying the information signal directly with a random sequence. From the information concealed through spreading, the original information can be extracted by multiplying the same spreading signal used for spreading.

The information concealment by the above-described DS method will be described in detail with reference to the drawings.

1 is a schematic block diagram showing a conventional information concealment apparatus using a random sequence.

As shown in FIG. 1, the first random sequence 102 in the form of noise having no correlation with the information signal 100, the first multiplier 104 for multiplying the random sequence 102 and the information signal 100, The adder 108 outputs a predetermined digital image signal for concealing the information signal, that is, a stago image obtained by adding the cover image 106 and the signal output from the first multiplier 104 and the cover image 106. And a second multiplier 114 for extracting the original information signal 112 by multiplying the second random sequence 110 having the same form as the first random sequence 102 by the stego image.

The information concealment apparatus configured as described above spreads the information signal 100 by multiplying the information signal 100 and the first random sequence 102 by the first multiplier 104, and outputs it from the first multiplier 104. The diffused information signal 100 is combined with the cover image 106 by the adder 108 to transmit a stego image that conceals the information signal.

The original information signal is restored by multiplying the same second random sequence 110 as the first random sequence 102 by the second multiplier in order to recover the received stego image.

As described above, since a signal having a constant information is spread by a spreading code or frequency pattern such as a random sequence, it is noise that is meaningless to an illegal user who does not know the used frequency pattern or spreading code, but the exact frequency pattern. And since the person who knows the spreading code can extract the hidden information, it naturally has a high secretion characteristic.

In addition, since it has a wide frequency bandwidth, it is robust to image compression using signal processing techniques such as fast fourier transformer or discrete cosine transform.

A method for concealing a plurality of information signals by the information concealment apparatus according to the conventional DS technique is as follows.

First, the different concealed signals and the random sequences multiplied by each concealed signal are called d ₁ and r ₁ , respectively, and the information signals and cover images spread by the random sequences are M (x, y) and C (x, y). In this case, the spread information signal M (x, y) and the stego image signal S (x, y) in which information to be distributed to various users are concealed may be represented by Equations 1 and 2, respectively.

Here, i represents the number of random sequences and the number of information signals used for multiple concealment.

The random sequence r ₁ used in Equation 1 is used for error-free restoration of the information signal.

Each other, such as 3, must have orthogonality that is the inner product of two vectors that are not zero. That is, the meaning of having orthogonality indicates that the random sequences r ₁ should not have the same value.

Where n is the number of pixels and G ² represents the average energy present in each pixel of the random sequence.

In addition, in the ideal case where the random sequence and the cover image do not have correlation with each other, the original signal can be accurately extracted even by concealing the information signal with the minimum energy. Since there is some correlation between the images, it is necessary to adjust the energy of the inserted information signal to a minimum for accurate reconstruction of the concealed information signal.

The reconstruction process of the concealed information signal may be represented by Equation 5 by the correlation between the stego image and the random sequence.

Since the information signal existing in the stego image created through this process is included at a lower energy level than the cover image, it is not easy to visually recognize the presence or absence of the information signal in the stego image, and Even if it is recognized, it is impossible to detect the information signal if the information on the random sequence produced by the numerous combinations is not known.

In addition, since stealth information is present in all frequency domains even when the Stego image is modified using a signal processing technique using a frequency domain, it is possible to detect the hidden information signal.

In the case of multiple information concealment, which hides several pieces of information in one digital image using a DS technique, each piece of information uses a different spreading code, that is, a random sequence. In this case, a random sequence without cross correlation is used for error-free extraction of the hidden information.

In other words, the random sequence should have characteristics such as white noise, and the repetition period must be infinitely long to satisfy such characteristics.

However, when the random sequence to be used to multiply the digital image by the conventional DS technique is used corresponding to the size of the digital image, since the length or area is limited, cross correlation cannot be completely removed, and thus exists in the random sequence. There is a problem that accurate information cannot be extracted when multiple hidden information is extracted due to a certain cross correlation.

Accordingly, the present invention has been made to solve various problems of the prior art, and a random sequence and a Hadamard matrix for multiple concealing a plurality of pieces of information by combining a spreading code for concealing information with a random sequence and a Hadamard matrix are provided. It is an object of the present invention to provide a multiple information hiding apparatus and method used.

1 is a schematic block diagram showing a conventional information concealment apparatus using a random sequence.

2 is a schematic block diagram of a multiple information concealment apparatus using a random sequence and a Hadamard matrix according to the present invention;

Figure 3a shows an 8 * 8 Hadamard matrix.

3b shows a random sequence of 8 * 8.

4A is a graph showing a correlation noise ratio when using a new spreading code versus an added noise when only a random sequence is used.

4B shows a histogram for FIG. 4A.

5 is a schematic operation explanatory diagram for concealing Roman II using random sequence and Hadamard matrix according to the present invention.

FIG. 6 is a schematic operation explanatory diagram for extracting Roman II hidden by FIG. 5; FIG.

7A is a diagram showing an energy spectral distribution of an information signal.

FIG. 7B illustrates the spectral distribution of the concealed information signal with the new spreading code.

8 illustrates multiple information signals to be concealed.

FIG. 9 illustrates a random sequence and first and third Hadamard matrices for concealing multiple information of FIG. 8; FIG.

10A illustrates a cover image for concealing an information signal.

FIG. 10B is a diagram illustrating a resonant frequency of an information signal band-spread by a spreading code formed by the random sequence and the Hadamard matrix of FIG. 9; FIG.

10C is a diagram illustrating a stego image in which an information signal is concealed.

11 and 12 show original information of extracted from an information signal concealed by a new spreading code.

FIG. 13A shows a stego image compressed by a Joint Photographic Expert Group (JPEG). FIG.

Fig. 13B shows an information signal before threshold processing extracted from a compressed stego image.

13C is a diagram showing an information signal after the threshold processing in FIG. 13B.

14A is a diagram illustrating a stego image with Gaussian noise added.

FIG. 14B is a diagram showing an information signal before threshold processing in which the information signal is extracted from the stego image of FIG. 14A; FIG.

FIG. 14C is a diagram showing an information signal after threshold processing of the information signal extracted from the stego image of FIG. 14A. FIG.

<Explanation of symbols for the main parts of the drawings>

210: encoding means 211: first random sequence

212 first Hadamard matrix 213 first multiplier

214: information signal 215: second multiplier

216: cover image 217: adder

220: decoding means 221: second random sequence

222: second Hadamard matrix 223: third multiplier

224 fourth multiplier

In order to achieve the above object, the present invention multiplies a Hadamard matrix having an orthogonality and a random sequence to generate a new spreading code, multiplies the new spreading code by an information signal to be concealed, and spreads the band and spreads the spread spectrum information signal. Inserts a predetermined video signal into the output signal and outputs the concealed signal of the information signal, extracts the original information signal from the concealed signal output by the spreading code of the same form as the new spreading code, and then extracts the information signal. It is characterized by providing a multi-sequence concealment method using a random sequence and a Hadamard matrix, which is configured to perform a critical process of setting the value to 1 when the value is greater than or equal to 1 and setting the value to 0 when the extracted information signal is less than or equal to a predetermined value.

In addition, the present invention has another feature in that a random sequence and a Hadamard matrix have a basic set of 64 × 64 pixels, and a multiple information concealment method using a random sequence and a Hadamard matrix having a basic set of 8 * 8 forms. .

The present invention also provides a Hadamard matrix having an orthogonality, a first multiplier for generating a spreading code by a Hadamard matrix and a random sequence, a second multiplier for spreading a band of an information signal to be concealed by the spreading code, and a constant image. An adder for concealing the information signal spread by the signal, a third multiplier for generating a Hadamard matrix having the same form as a Hadamard matrix and a random sequence, and a spreading code based on the random sequence, and concealed by a spreading code of the third multiplier And a fourth multiplier for extracting the original information signal from the extracted information signal and threshold processing means for setting the value to 1 when the extracted original information signal is greater than or equal to a predetermined value and to 0 when less than or equal to the predetermined value. And providing multiple information concealment apparatus using Hadamard matrix.

Hereinafter, an apparatus and method for concealing multiple information using a random sequence and a Hadamard matrix according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited or limited by the following examples.

2 is a schematic block diagram of a multiple information concealment apparatus using a random sequence and a Hadamard matrix according to the present invention.

As shown in FIG. 2, the present invention provides a decoding unit for restoring and extracting an encoding unit 210 that conceals a predetermined information signal and transmits it through a network, and an information signal concealed by the encoding unit 210. Means 220.

The encoding means 210 comprises a first random sequence 211 in the form of noise produced by numerous combinations, a first Hadamard matrix 212 having an orthogonality, a first random sequence 211 and a first Hadamard matrix 212. Multiply by a first multiplier 213 for outputting a spreading code and a spreading code output from the first multiplier 213 and an information signal 214 to output a spread information signal. The cover image 216 for concealing the signal 214 and the spread image signal output from the second multiplier 215 are added to the cover image 216 and transmitted to the decoding means 220 through the network. It consists of an adder 217 to make.

In addition, the decoding unit 220 may include a second random sequence 221 and a second Hadamard matrix 222 and a second random sequence having the same form as the first random sequence 211 and the first Hadamard matrix 212. 212) by multiplying the second Hadamard matrix 222 by multiplying the third multiplier 223 for outputting the spreading code and the spread code output from the third multiplier 223 and the stego image transmitted from the encoding unit 210. And a fourth multiplier 224 for extracting the original information signal 225.

Referring to the operation of the information concealment apparatus according to the present invention having such a configuration as follows.

First, if the Hadamard matrix is h _i (x, y), the first random sequence 211 and the first Hadamard matrix 212 are multiplied by the first multiplier 213 to obtain a new spreading code as shown in Equation (6). Outputs

Here, the equations representing the new spreading code, the correlation between the cover image and the new spreading code, and the extraction of the concealed information signal generated by the newly spreading code r _i ′ are shown in Equations 7 to 9 below.

As in Equation 7 to Equation 9, by using the newly generated spreading code r _i 'by multiplying the random sequence by the Hadamard matrix, the orthogonality of the Hadamard matrix can be satisfied while maintaining the noise-like property of the random sequence. Therefore, a new information concealment code having orthogonality can be generated in the same space.

A new spreading code based on a random sequence and a Hadamard matrix will be described with reference to FIG.

FIG. 3A illustrates an 8 * 8 Hadamard matrix, and FIG. 3B illustrates an 8 * 8 random sequence.

A new spreading code is generated by multiplying the complementary Hadamard matrix of FIG. 3A with the random sequence of FIG. 3B, wherein the Hadamard matrix and the random sequence are composed entirely of 512 × 512 pixels with a default set of 64 × 64 pixels. One basic set spreads an information signal while having orthogonality corresponding to a 1-bit information signal in which 64x64 pixels are configured with the same value of '1' or '0'.

A new spreading code generated by multiplying the above-mentioned random sequence by the Hadamard matrix and the correlation noise ratio according to the information hiding by the random sequence will be described with reference to FIG. 4.

FIG. 4A is a graph showing a correlation noise ratio when using added noise to a new spreading code when only a random sequence is used, and FIG. 4B is a histogram of FIG. 4A.

As shown in FIG. 4, when the information is concealed using a new spreading code based on the random sequence and the Hadamard matrix, 40 to 343% of the noise is reduced by the orthogonality of the Hadamard matrix compared to the information concealment using only the random sequence. Reduce the error in the extraction of information.

As described above, a new spreading code generated by multiplying the first random sequence 211 and the first Hadamard matrix 212 by the first multiplier 213 and the second multiplier 215 for the information signal 214 to be concealed. Multiply again to spread the band of the information signal 214.

The cover image 216 is added to the spread spectrum information signal 214 by the adder 217 to output an encoded stego image.

The second random sequence 221 and the second Hadamard matrix 222 that are identical to the first random sequence 211 and the first Hadamard matrix 212 are multiplied by the third multiplier 223 to generate a new spreading code. .

The new spreading code and the transmitted stego image are multiplied by the fourth multiplier 224 to extract the original information signal 225.

An embodiment of information hiding using a random sequence and a Hadamard matrix according to the present invention will be described with reference to the accompanying drawings.

FIG. 5 is a schematic operation explanatory diagram for concealing Roman II by using a random sequence and a Hadamard matrix according to the present invention, and FIG. 6 is a schematic operation explanatory diagram for extracting Roman II being concealed by FIG. FIG. 7A is a diagram illustrating the energy spectral distribution of the information signal, and FIG. 7B is a diagram illustrating the spectral distribution of the information signal concealed by the new spreading code.

As shown in FIG. 5, the random sequence 500 and the Hadamard matrix 502 are multiplied by the first multiplier 504 to generate a new spreading code, and the second multiplier 506 generates a new spreading code and information signal 508. Outputs a spread spectrum information signal having orthogonality.

Subsequently, the spreader information signal output from the second multiplier 506 and the cover image 510 are summed by the adder 512 to output a stego image 514. Here, the stego image 514 is similar to the cover image 510, and thus it is not possible to easily determine whether the information signal is concealed, and although it is possible to know whether the information signal is concealed or not, a new spread generated by the Landon sequence and the Hadamard matrix. The high incompatibility of the code makes it difficult to extract hidden information signals.

In addition, as shown in FIG. 6, the Stego image 514 output by the information concealment process as shown in FIG. 5 is the same as the Hadamard matrix 502 and the random sequence 500 used in the information concealment process of FIG. 5. The Hadamard matrix 600 and the random sequence 602 are multiplied by the third and fourth multipliers 604 and 606, respectively, to extract the concealed information signal to accurately obtain the original information signal 607.

Referring to FIG. 7 again, the information signal modulated by multiplying an information signal to be concealed by a spreading code having a bandwidth wider than that of the information signal is shown in FIG. 7A. At this time, the constant energy of the information signal becomes small in inverse proportion to the size of the widened bandwidth. If the multiplied multiplication signal is multiplied by the same spreading code, the bandwidth of the spread information signal is spread back to the original bandwidth of the information signal and the original information is obtained. The signal is extracted.

Therefore, even if multiple information concealment codes of information signals having a certain energy level, i.e., multiple overlapping using a random sequence, are overlapped with the lower energy level, the information signal is not recognized in the stego image. By multiplying again, multiple information signals can be extracted.

Another embodiment of the multiple information concealment method using the random sequence and the Hadamard matrix according to the present invention as described above will be described with reference to the accompanying drawings.

FIG. 8 is a diagram illustrating multiple information signals to be concealed, and FIG. 9 is a diagram illustrating a random sequence and first and third Hadamard matrices for concealing multiple information of FIG. 8. FIG. 10A illustrates a cover image for concealing an information signal, and FIG. 10B illustrates a resonant frequency of an information signal spread by a spreading code formed by a random sequence and a Hadamard matrix of FIG. 9, and FIG. 10C. Is a diagram showing a stego image where the information signal is concealed. 11 and 12 are diagrams illustrating original information of s extracted from an information signal concealed by a new spreading code.

First, as shown in FIG. 8, the random sequence and the first through the third to third information signals composed of all of the Roman letters 'I', 'II', and 'III' composed of all 64 bits having one 64 × 64 pixel as one bit are shown. After multiplying three spreading codes generated by multiplying the Hadamard matrix, a stego image as shown in FIG. 10C having a band spread is obtained by adding a cover image as shown in FIG. 10A. At this time, since the stego image where the information signal is concealed is almost the same as the cover image, the information signal cannot be distinguished.

Here, since the three spreading codes generated by the random sequence and the Hadamard matrix of FIG. 9 are not correlated with each other, the parameters used can be easily modified to conceal more information without errors.

When the information signal concealed with the spread spectrum band as shown in the stego image of FIG. 10C is detected by the same random sequence and the spreading code generated by the Hadamard matrix as shown in FIG. 9, the output signal is output as shown in FIG. 11. Constant noise due to the correlation between the image and the new spreading code is included.

Therefore, when the threshold processing is performed to remove noise due to the correlation between the cover image and the information concealment code as shown in FIG. 11, the correct original information signal is extracted as shown in FIG. 12.

Here, the threshold processing will be described. In general, image processing data may be classified into color, gray, and binary, and binary image data may be classified into two colors, black and white, using a gray threshold value. This is data that handles data.

The boundary value processing of the binary image data, that is, the threshold processing, sets the pixel value of the output image corresponding to the case where the pixel value of the input image is equal to or greater than a certain value having brightness to 1, and otherwise sets it to 0. In this case, various results may be obtained according to how the threshold value is set and how image data is processed based on the threshold value.

The image compression by the information concealment apparatus and method using the random sequence and the Hadamard matrix according to the present invention will be described with reference to the accompanying drawings.

FIG. 13A is a diagram illustrating a stego image compressed by a Joint Photographic Expert Group (JPEG), and FIG. 13B is a diagram showing an information signal before threshold processing extracted from a compressed stego image, and FIG. 13C is after the threshold processing of FIG. 13B. Is an illustration of an information signal.

As shown in FIG. 13A, a stego image in which an information signal is spread by a random sequence and a Hadamard matrix is compressed by a JPEG having an image characteristic of 80% and transmitted through a predetermined network, and the receiving side receives a band. Extracting the information signal concealed by the same random sequence spread and the Hadamard matrix is shown in FIGS. 13B and 13C, which can extract accurate information without generating an error in image compression to some extent.

FIG. 14A is a diagram illustrating a stego image with Gaussian noise added, and FIG. 14B is a diagram illustrating an information signal before threshold processing, in which an information signal is extracted from the stego image of FIG. 14A, and FIG. 14C is a diagram of the stego image of FIG. 14A. The figure shows the information signal after the threshold processing of the extracted information signal. The concealed information is accurately recovered even with the Gaussian noise generated when the concealed information signal is transmitted through a predetermined network.

The method and apparatus for multiple information concealment using the random sequence and the Hadamard matrix according to the present invention generate a new spreading code using the Hadamard matrix and the random sequence having orthogonality, and thus conceal the multiple information by the new spreading code. When the multiple information is hidden by the random sequence, noise can be prevented due to the cross-correlation of the random sequence, so that accurate extraction of the hidden multiple information can be performed.

In addition, there is an effect that it is possible to perform accurate extraction of the concealed information on the image compression algorithm when the concealed information signal is transmitted through the network and Gaussian noise that may be generated on the communication path.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to vary the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated that modifications and variations can be made.

Claims (11)

Generating a new spreading code by a Hadamard matrix having randomness and a random sequence; Spreading a band of the information signal to be concealed by the spreading code; Inserting a predetermined video signal into the spread spectrum information signal and outputting a concealed signal of the information signal; Extracting an original information signal from the concealment signal by a spreading code identical to the spreading code Multiple information hiding method using a random sequence and Hadamard matrix comprising a. The method of claim 1, The new spreading code is a multiple information concealment method using a random sequence and a Hadamard matrix generated by multiplying the random sequence and the Hadamard matrix. The method of claim 1, The concealment signal is a multiple information concealment method using a random sequence and a Hadamard matrix generated by adding the spreading code and the information signal. The method of claim 1, And the random sequence and the Hadamard matrix have a basic set of 64 × 64 pixels, and the basic set has a 8 * 8 form. The method of claim 1, Performing threshold processing to set the extracted original information to 1 when the extracted original information is equal to or greater than a predetermined value and to set it to 0 when the extracted original information is equal to or less than the predetermined value; Multiple information concealment method using a random sequence and Hadamard matrix further comprises. The method of claim 1, And a predetermined sequence signal and the concealment signal comprises a substantially identical image. Hadamard matrix with orthogonality; A first multiplier for generating a spreading code based on the Hadamard matrix and a random sequence; A second multiplier for spreading a band of the information signal to be concealed by the spreading code; An adder for concealing the spread spectrum information signal by a predetermined video signal; A third multiplier for generating a spreading code based on the Hadamard matrix and the random sequence having the same form as the Hadamard matrix and the random sequence; A fourth multiplier for extracting an original information signal from the concealed information signal by a spreading code of the third multiplier Multiple information concealment apparatus using a random sequence and Hadamard matrix comprising a. The method of claim 7, wherein The spreading code is a multiple information concealment apparatus using a random sequence and a Hadamard matrix generated by multiplying the random sequence and the Hadamard matrix. The method of claim 7, wherein The concealment signal is a multiple information concealment apparatus using a random sequence and a Hadamard matrix generated by adding the spreading code and the information signal. The method of claim 7, wherein And the random sequence and the Hadamard matrix have a basic set of 64 × 64 pixels, and the basic set has a 8 * 8 form. The method of claim 7, wherein Threshold processing means for setting it to 1 when the extracted original information is equal to or greater than a predetermined value and to 0 when it is smaller than or equal to the predetermined value. Multiple information concealment apparatus using a random sequence and Hadamard matrix further comprises.