JP2002269075A - Embedding of information in document and decoding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secretly transmit secret information by embedding different information in a digitized ordinary document and decoding the information. SOLUTION: A standardized document is generated (step S110) by substituting a basic word for wording which can be rewritten with a word and/or representation showing the same concept in a document constituting an arbitrary document (original) according to a mutually shared dictionary database. According to a data row obtained from the data to be embedded through binary coding, coding processing for rewriting the standard document into a basic word for 0 and a word other than the basic word for 1 from the beginning is performed (step S130). The decoded document is a very natural document which seems to be the same with the original at a glance. The coded document makes it possible to reproduce the embedded data by decoding differences from the standardized document by algorithm reverse to the above algorithm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an information embedding technique for embedding desired information in an arbitrary digitized text and an information decoding technique for decoding the embedded information.

[0002]

2. Description of the Related Art With the progress of word processors and character reading devices, personal sentences such as diaries and letters, business sentences such as contracts, and specialized sentences such as papers and novels have been digitized. Also, with the dramatic improvement of information distribution technology such as the Internet, it is possible to instantly distribute digitized text to the world or to disclose it to the public.

[0003] On the other hand, digitized texts can be easily copied and edited, such as changing or deleting only a part thereof, easily. The sentence digitized in this way is different from a sentence written in characters on paper, and an infinite use form can be considered depending on a user's idea. Such various forms of use can sometimes bring unforeseen disadvantages to the rightful right holder of the digitized text. Therefore, techniques for protecting digital information such as images and data, not limited to digitized sentences, are being developed. For example, as this type of protection technology, an encryption technology for transmitting and receiving secret information on the Internet, a digital watermark technology for embedding copyright information and the like in a digital work, and the like are known. According to these information protection technologies, a digitized text can only be recognized as a meaningless character string without using an encryption key. The use of the sentence can be restricted.

[0004]

However, the following problems have not been solved in the conventional digital text encryption technology and digital watermarking technology. Conventional encryption technology converts digitized text into meaningless character strings and distributes them, so the protected text has no meaning unless it is restored using an encryption key. It is possible to distribute and disclose the sentence without worry.

On the other hand, when a third party finds a meaningless character string on the Internet or the like, the character string is an encrypted sentence, and the character string contains some information that is important enough to be encrypted. Can be easily known that is hidden. Therefore, these encrypted character strings are suitable targets for so-called hackers and the like, and are exposed to a risk that the encryption is broken. In addition, since a meaningless character string is immediately identified as an encrypted text, for example, even if you want to contact a friend secretly, the fact that you exchanged with the encrypted text is It is easily understood by a third party.

[0006] On the other hand, in the case of a digital watermark, the exchanged data itself is not encrypted, so that the above problem does not occur. However, digital watermarks are usually embedded in the original data in a form that cannot be read by human audiovisual information, so that highly redundant information such as images and music can easily embed a considerable amount of data. Although,
It has been difficult to embed information in text data, especially plain text data without any decoration. In the case of Japanese character codes, for example, one character is represented by two bytes (16 bits). However, changing any one bit corresponds to a different character code. We can't embed any information here.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and embeds different information in a digitized ordinary text and reproduces the information.
An object of the present invention is to provide an excellent information embedding technology and an information reproducing technology that can transmit secret information in secret.

[0008]

Means for Solving the Problems and Their Functions / Effects To achieve the above object, the present invention provides
First, a method of handling information will be described. That is, the information handling method of the present invention is a method of handling information for embedding and decoding desired information in a digitized text, and based on a predetermined rule, different words and / or notations but the same. A standardization step of rewriting the sentence into a standard sentence by a word and / or a notation representing a concept; and a word and / or notation rewritten in the standardization step, the data according to the desired information, Determining whether to use a word and / or a notation representing the same concept, and embedding the data by rewriting the sentence; and receiving an encrypted sentence in which the data is embedded by the step; Extracting the rewritten words and / or notations of the encrypted text based on the extracted words and / or tables. Based on, and summarized in that and a decoding step of decoding the embedded data.

According to this information handling method, a process for standardizing a digitized text is performed,
At the time of this standardization, it is determined according to data corresponding to the information to be embedded, which of the words and / or notations representing the same concept used in the standardization is to be used, and the text is rewritten accordingly. Then, the data is embedded in the text to generate an encrypted text. When decrypting the encrypted text, a rewritten word and / or notation is extracted from the encrypted document based on a predetermined rule, and the embedded data is decrypted from the extracted word and / or notation.

That is, according to the information handling method of the present invention,
In digitized text, not the data itself,
A part for standardizing different words and / or notations is provided with redundancy, and data corresponding to desired information is embedded therein. For this reason, other information can be embedded in information that is considered to have little redundancy, such as text data. Moreover, in this case, since the digitized text can be read as it is, there is an advantage that the fact that the data is embedded is not apparent from the appearance.

The information embedding device of the present invention corresponding to such a method is an information embedding device for embedding desired information in a digitized sentence, wherein different words and / or notations are used based on a predetermined rule. The standardization means for rewriting the sentence into a standard sentence by a word and / or notation expressing the same concept, and the word and / or notation rewritten in the standardization step, in accordance with data corresponding to the desired information An embedding unit that determines which of a word and / or a notation representing the same concept is to be used and rewrites the sentence to generate an encrypted sentence in which the data is embedded.

Thus, the information embedding apparatus of the present invention generates an encrypted text by rewriting the digitized text with words and / or notations representing the same concept as the text constituting the text. Can be. Therefore, the encrypted text is generated as a very natural text that at first glance is not different from the original text. Therefore, there is an advantage that the fact that other data is embedded is not apparent from the appearance.

The encrypted text is obtained by temporarily rewriting words and / or notations constituting the original text into a standard text and standardizing the standard text, and rewriting the standard text according to data and predetermined rules. Therefore, by detecting the difference between the encrypted text and the standard text by the reverse algorithm of the predetermined rule, the data embedded in the encrypted text is
It can be easily extracted. Then, it becomes possible to reproduce the desired information embedded from the extracted code. Such an information embedding device of the present invention, for example,
A wide variety of applications are conceivable, such as a digital watermark for embedding copyright information or information for specifying an information distributor, for encryption transmission.

Here, it is preferable that the standardizing means and the embedding means use the same dictionary database as a predetermined rule for rewriting words and / or notations. Note that the dictionary database is, for example, disclosed in
No. 73171, JP-A-10-240743,
As disclosed in JP-A-6-301718 and JP-A-62-17872, various techniques used to change a variety of sentences caused by uncertainty of words and notations into a constant expression are disclosed. Available. You can use so-called thesaurus and synonym dictionaries, etc., and the fluctuation of the notation in Japanese, for example, the fluctuation of the notation such as "rewrite" and "rewrite", and the fluctuation of the treatment of long sounds such as "energy" and "energy" It is also possible to use such as. Since such a dictionary database tends to be complicated and large in volume for more natural sentence creation, by using the same dictionary database for standardization means and embedding means, the information embedding device can be reduced in size. Inexpensively, the processing speed can be improved.

Preferably, the dictionary database has characters, words, and phrases at the stage of rewriting. Rewriting to words and / or notations that represent the same concept is complicated in the order of rewriting characters such as full-width katakana to half-width katakana, rewriting words using synonyms, rewriting phrases by analyzing sentences, and The rewriting causes a subtle difference in concept.
Therefore, by configuring the dictionary database to include the stages of characters, words, and phrases, the rewriting becomes effective stepwise from the character level to the phrase level according to the amount of information to be embedded. It is possible to embed information at a higher speed and with less change in concept.

Further, it is more preferable that the dictionary database is configured so that use of arbitrary data is prohibited and / or data can be changed. The information embedding apparatus that has customized the dictionary database in this way can embed information that can be reproduced only by a person having the same regularity as the customized dictionary database. Confidentiality of the information can be further improved.

The standardizing means may be configured to include a difference data generating unit for generating difference data based on a difference between the digitized text and the standard text when rewriting the digitized text into a standard text. Such difference data can be used to reproduce the original digitized text from the encrypted text.

The above-described information embedding device is significant not only as a completed device but also as a processing method which is an algorithm of the processing. That is, the information embedding method as another invention is an information embedding method for embedding desired information in a digitized text, and based on a predetermined rule, the same concept is used although different words and / or notations are used. A standardization step of rewriting the sentence into a standard sentence by a word and / or notation to be expressed, and the same concept according to data corresponding to the desired information regarding the word and / or notation rewritten in the standardization step. And embedding a step of rewriting the sentence to embed the data by deciding which of the word and / or the notation to use.

It is obvious that the same operation and effect as the above-mentioned information embedding device can be achieved by the invention of this method. In addition, in order to realize the processing method according to the invention of the method on a computer, the method is configured as a program to be executed by a computer, and the program is distributed over the Internet or the like, or a CD-ROM, a floppy (registered trademark) disk, May be recorded on a recording medium and distributed.

The encrypted text in which the desired information is embedded by the information embedding apparatus, the method and the program described above is analyzed by the information reproducing apparatus of another invention as follows, and the desired information embedded is embedded. Can be easily reproduced. That is, an information decryption device according to another invention is an information decryption device that decrypts data corresponding to the desired information from an encrypted text obtained by the information embedding device according to claim 1, wherein Extraction means for extracting the rewritten word and / or notation of the encrypted text based on rules, and decoding means for decoding the embedded data based on the extracted word and / or notation The gist is that.

The extracting means in the present invention extracts the rewritten word and / or notation of the encrypted text based on a predetermined rule. Then, the decoding means decodes the embedded data based on the words and / or notations extracted by the extracting means.

Thus, the information reproducing apparatus of the present invention can reproduce the desired data embedded in the encrypted text, which is a normal digitized text, and can reproduce the desired data through the encrypted text. Receiving can be done secretly. Therefore, upon receiving the encrypted text in which the desired information is embedded, it seems to the third party that the reception of the encrypted text itself is meaningful, and it is desirable to leave a trace of secret communication without leaving any trace. Information can be received. For this reason, it is not necessary to tell that the data is embedded unnecessarily, and it is possible to increase the reliability of confidentiality.

The information reproducing apparatus of the present invention which exhibits such excellent effects is paired with the above-mentioned information embedding apparatus, for example, for encryption transmission, copyright information or information for specifying an information distributor. A wide variety of applications are conceivable, such as as a digital watermark that embeds a.

Here, the extracting means includes, as a predetermined rule for extracting the rewritten word and / or notation,
It is desirable to use the same dictionary database as the standardization means and embedding means described above. This is because the use of a predetermined dictionary database greatly improves the information reproduction accuracy. Also, if this dictionary database is customized, it is impossible to reproduce desired information even with an information embedding device or an information reproducing device having a similar algorithm. Performance is further improved.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the configuration and operation of the present invention described above, embodiments of the present invention will be described below through examples. (1) Configuration of the embodiment: FIG. 1 shows a program embodying an information embedding method and an information decoding method according to an embodiment of the present invention installed in computers 20 and 30 connected to a network 10 such as the Internet. An example is shown. Also, many other computers 4
Numeral 0 denotes an unspecified user connected to the network 10, and the computer 20 exchanges text data such as e-mail with the users of the many computers 30 and 40. I have. Some of these computers 40 include malicious users who try to illegally obtain information circulating on the network 10. In this embodiment, the following example will be described. First, the computer 20 embeds information in a digitized text (text data), and then sends the text to another computer 30 via the network 10. Next, the computer 30 that has received the mail reproduces the information embedded in the computer 20 from the text of the mail.

FIG. 2 shows the internal configuration of the computers 20 and 30.
It was shown to. In this figure, the computer 20 is taken as an example. The computer 20 includes a network interface (NT-I / F) 21 for controlling data exchange with the network 10 via a modem or a router 18.
CPU 22 for processing, ROM 23 for storing processing programs and fixed data, RA as a work area
M24, a timer 25 for managing time, a display circuit 26 for controlling display on a monitor 29, a hard disk (HD) 27 for storing various data described later, and an input interface (I / F) for controlling an interface with the keyboard 11 and the mouse 12. ) 28 etc. The hard disk 27
Has been described as a fixed type, but a removable type may be used, or a removable storage device (CD-ROM,
CD-R, CD-RW, DVD, flexible disk, etc.). In this embodiment, the processing program of the computer 20 is stored in the ROM 2
3 is stored in the hard disk 2
7, and may be developed and executed on the RAM 24 at the time of startup. Alternatively, the data may be read from the above-mentioned removable recording medium. Furthermore, the program may be read from another server via the network 10 and executed.

In the computer 20 shown in FIG. 1, a user edits a document (text data) inputted from the keyboard 11 or text data taken from the outside via the network 10 and finally edits the hard disk 2.
7 is stored. Then, this is attached to the mail as an attached document and transmitted to the user of another computer 30 via the network 10.

In the present embodiment, the computers 20, 30
Stores a dictionary database DDB for standardizing documents, in addition to a dictionary for kana-kanji conversion, on the hard disk 27. FIG. 3 is an explanatory diagram of a data example of the dictionary database. As shown in the figure, the dictionary database is a collection of standardized dictionaries in which words and notations that are different words and notations but represent the same concept, that is, so-called skewed data are accumulated. The computer 20 performs the following four levels of standardization on the text created and stored on the hard disk 27. Character standardization processing (standardization of characters to be replaced with predetermined characters), character-level notation fluctuation, and unification of notation fluctuations that have no change in the concept, such as the presence or absence of long sounds in katakana endings and katakana full-width / half-width characters is there. Notation unification processing (processing to unify notation fluctuation to a predetermined notation), word-level notation fluctuation, and unification of plural kanji notations with almost no difference in meaning. Independent word processing (processing of replacing an independent word with another independent word in accordance with a predetermined replacement criterion), which is a fluctuation of the notation of the independent word, and performs replacement between words that may have slightly different meanings, It unifies the independent words used. Adjunct processing (processing to replace adjuncts with other adjuncts in accordance with prescribed rules) This is to unify fluctuations in phrase-level notation, stop redundant sentence and body expressions, use plain and ordinary expressions, and passive expressions And unify the passive language.

The fourth attached word processing (processing of swaying of the notation at the phrase level) is performed before and after by a so-called sentence standardization technique or the like, which is used to change the diversity of the sentence into a constant expression. FIG. 3 shows an example in order to explain that it is a part of the data of the dictionary database, taking into account the sentence and the usage of words.

In the computer 20, an information embedding program as shown in the flowchart of FIG. 4 is executed to embed desired information in an arbitrary digital text. When the information embedding program is executed, first, a process of specifying a digital text (hereinafter simply referred to as an original text) to be embedded with information is performed (step S100), and a user of the computer 20 is prompted to specify the original text. I do. The original text may be specified by a document stored in the hard disk 27 or may be specified as a document created by e-mail or the like and temporarily stored in mail software. FIG. 5 shows the computer 20 in this specific processing (step S100).
This is an example of the original sentence specified by the user.

When the original sentence is specified in this manner, a standardization process (step S110) for specifying the fluctuation of the expression existing in the sentence of the original sentence and standardizing the expression is then performed. FIG.
Is a display screen displayed on the computer 20 when the standardization process is executed. As shown in the figure, a check box RB1 for specifying at which level of the character level, word level, or phrase level the standardization process is to be performed, and a radio button R for selecting whether or not to create difference data described later.
B2 and a button B for instructing execution and cancellation of standardization
B3 and BB4 are prepared. In the present embodiment, a case will be described in which the word level is selected as the standardization level and "create" is selected in the difference data as shown in FIG. 6, and the execution button BB3 is clicked.

When the standardization level is the word level,
In the original sentence shown in FIG. 5, the notation fluctuation defined at the character level and the word level in the dictionary database is searched, and a standardization process for replacing all the search results with basic words is performed. Therefore, in the present embodiment, the original is
Will be rewritten as shown in In addition,
In FIG. 7, () is attached to the fluctuation of the notation existing in the original sentence, and [] is added to the fluctuation of the notation replaced by the basic word. This standardization process (step S
110), the original sentence is rewritten into a sentence using the basic words of the dictionary database (hereinafter referred to as a standardized sentence).

When creation of difference data is selected, 0 is assigned to () and 1 is assigned to [] for each of the notations shown in () and [] in FIG. A data string is created. Therefore, in the example shown in FIG. 7, the data string is “0100000000000001”. Then, this data string is divided into eight from the beginning,
A binary representation of an 8-bit ASCII code is determined as difference data. If the data string is not a multiple of 8, data of 0 is added and adjusted at the end so as to be a multiple of 8. Therefore, the difference data in this embodiment is two-byte data of “01000000b” (“b” indicates binary data) and “00000010b”. In addition, this binary code is AS
When converted into a CII code, they correspond to “＠” and “SX” (control code).

In this way, the original text is standardized (step S1).
When the standardized text and the difference data are prepared after 10), the process of specifying embedded information for prompting the user of the computer 20 for information to be embedded next is performed (step S120). In this processing, data to be embedded is specified by a method such as specifying an electronic file in which information to be embedded is described in advance, or directly inputting information from the keyboard 11 of the computer 20 by a key. Hereinafter, in the present embodiment, a case where a character “A” (half-width) is input from a keyboard as data to be embedded will be described.

When data is input from the keyboard 11, an encryption process (step S130) is executed in response to the data. In this encryption process, assuming that the information to be embedded is a single-byte “A”, the ASCII code “41”
Is converted to binary data "010000001b". According to this bit string, the standardization execution portions indicated by () and [] in FIG. A process of rewriting to a synonym other than a character is performed. That is, the second and eighth characters from the beginning of the shaking of the notation shown in ()
The “engineer” is rewritten to “your company” and “occupation” different from the basic characters, and a text as shown in FIG. 8 (hereinafter referred to as an encrypted text) is created.

Subsequently, processing for outputting difference data is performed (step S140). The difference data is obtained by similarly converting the difference between the original sentence and the standardized sentence into a bit string of “0” and “1”. In the present embodiment, the difference data is output in a form attached to the encrypted text, but may be output as a file different from the encrypted text.

Thus, the user of the computer 20
An encrypted text in which the data “A” is embedded can be obtained, and the encrypted text is transmitted to the computer 30 as mail. At this time, the difference data can be attached to the mail, or the difference data can be included in the encrypted text as embedded information and transmitted.

According to the above-described encryption processing of this embodiment, different data can be superimposed on normal text data and embedded. That is, other data is embedded here by skillfully utilizing the redundancy obtained by the work of standardizing text data. Moreover, the encrypted text obtained in this way can be read in the same manner as ordinary text, so that there is no fear that others will realize that the text is a cipher text. Further, since the data is embedded by making the words and notations constituting the text different, the obtained encrypted text can be understood as it is if read.

Next, an information decryption program for reproducing the information "A" from the encrypted text by the computer 30 will be described. FIG. 9 is a flowchart of the information decoding program executed by the computer 30. When this program is executed, the computer 30 executes a decoding point determination process (step S200) for determining the point of information decoding. FIG. 10 shows a display screen displayed on the monitor 29 of the computer 30 at the time of executing the decryption point determination process. As shown in the figure, a check box RB11 for designating which and which of the character level, the notation fluctuation level, the independent word level, and the attached word (phrase) level are to be used, and the A radio button RB12 for specifying the presence / absence and buttons BB13 and BB14 for instructing execution and cancellation of decoding are provided. In the present embodiment, description will be made on the assumption that a user of the computer 20 transmits a word-level encrypted text and also transmits difference data attached to an e-mail. In this case, a word-level check box and a radio button indicating that there is difference data are selected as shown in FIG. 10, and an execution button is clicked. The level of decryption cannot be determined unless the sender and receiver of the data match. Therefore, if the level of the decryption is kept confidential to both parties, the reliability of the encryption can be further enhanced. Needless to say, the same decryption dictionary database must be used for both, and in this regard, the reliability of the encryption is extremely high.

Subsequently, a process of specifying an encrypted text (Step S210) for prompting the user to specify a text file is performed, and a process of reading the specified encrypted text is performed. The user of the computer 30 specifies the encrypted text (FIG. 7) attached to the mail at this time.
At this time, the difference data is also read.

In the subsequent decryption process (step S220), the specified encrypted text is searched from the beginning of the text of the encrypted text using the dictionary database illustrated in FIG. Is performed. A data string is created to be 0 when the fluctuation of the notation is a basic word and 1 when it is other than a basic word, and this data string is divided into eight from the beginning. For example, in the case of the encrypted sentence shown in FIG. 8, the words that can be standardized in the first eight places are "basic word", "other than basic word", "basic word", "basic word", and so on. Therefore, if these are converted into binary codes for the first eight locations, “010
A data string “00001b” is created. This is A
When converted to the SCII code, the character "A" is decoded.

Next original text reproduction process (step S230)
Is a process executed only when it is checked in step S200 that there is difference data.
0 prompts the user to identify the difference data and obtains it,
The original text is reproduced from the encrypted text. In this process, all the fluctuations of the notation are converted into basic words in order to first convert the encrypted text back into the standardized text. Then, the specified difference data “＠” and “SX” are converted into a binary code,
Based on the data of (1) and (1), a process of rewriting to a character other than the basic character is performed if the value is 0 from the beginning of the standardized sentence and remains as the basic character. By this processing, the encrypted text shown in FIG. 8 is converted into the original text shown in FIG. 5, and the text created first by the user of the computer 20 can be reproduced. In the above description, the embedding data has not been subjected to a compression process or the like for the sake of convenience of understanding, but the data embedded in the text is actually compressed. As a compression technique, a known technique such as LZ encoding can be used. By compressing the information to be embedded, the amount of information that can be embedded in the text data increases, so when embedding the difference information for restoring the original text together as in this embodiment,
The effect is particularly great.

According to the information embedding method and the information reproducing method of the present embodiment configured as described above, the network 1
The encrypted text transmitted / received via “0” is in the form of an ordinary text (see FIG. 8), and other data (“A” in this embodiment) is embedded in this text. Not noticed. Different information can be embedded in a digitized ordinary text to form an encrypted text, and the encrypted text can be used to secretly transmit desired information. Therefore, when the encrypted text in which the desired information is embedded is delivered, it seems to a third party that the delivery of the encrypted text itself is meaningful, and the desired content can be obtained without leaving a trace of secret communication. Information can be distributed. Therefore, highly reliable secret protection is achieved without being subject to code breaking by hackers or the like.
In addition, reading the encrypted text makes sense and can also be used to convey information. In this embodiment, the use form of the encryption for embedding the information “A” has been described. However, if the information to be embedded is copyright information, it can be used as an electronic watermark.

The dictionary database shown in FIG. 3 can arbitrarily set three levels of character level, word level, and phrase level as candidates for rewriting. Therefore, when it is desired to suppress the difference between the original text and the encrypted text with a slight difference in expression, the character level or the swaying level of the notation is selected, and when the amount of information to be embedded is large, the independent word level and the attached word (phrase) level are also selected. Various uses are possible. Moreover, the original text is standardized (step S11).
By creating the difference data at the time of 0), the original text can be faithfully reproduced from the encrypted text, and even if a nuance is required, the encrypted text can be created with confidence, and the secret information embedded Can be sent.

Note that, in the dictionary database shown in FIG. 3, the notation to be standardized is either an alternative.
Actually, for example, in the independent word "important", there are many synonyms such as "important" and "important" in addition to "important". In addition, there may be a word having a plurality of notations such as “rewrite”, “rewrite”, and “rewrite”. In the case of replacing a self-contained word having a large number of such synonyms, for example, a word arrangement in a dictionary may be used to replace a word arranged immediately after a basic word used in standardization. . In addition, the difference data may be generated by expressing the number of words replaced with a plurality of bits. That is, synonyms such as "important, important, important, important" are arranged in this order in the dictionary database, and it is assumed that the basic word is "important" and the original sentence is "important," When it is replaced with the basic word “important”, the distance from the basic word is 2 and “10”
That is, the difference data is generated. In this way, even if the standardized dictionary database has a plurality of replacement words for one basic word, encryption and decryption, and further, original text recovery can be performed.

The present invention is not limited to the above embodiment, but may be embodied in various forms without departing from the gist of the invention. For example, the dictionary database may be customized by adding a dictionary utility program which enables the use of arbitrary data in the dictionary database and / or changes data in the above embodiment. If the users of the computers 20 and 30 share the customized dictionary database, even if the encrypted text is illegally obtained by another computer 40 that transmits and receives the cipher using the same algorithm, the original text and the The confidentiality can be further improved without the embedded information being reproduced.

Further, in the above-described embodiment, an example has been described in which the use of a basic word or other characters is made to correspond to 0 or 1, thereby embedding 1-bit information by using a fluctuation of one notation. However, multiple bits may be embedded in the fluctuation of a specific notation. For example, the basic word “the other day” in the dictionary database illustrated in FIG.
Assuming that four replacement words “previous”, “overdue”, and “recently” are registered, the basic words “previous” are “0”, “previous” is “1”, and By associating “00” and “earlier” with “01”, it is possible to embed 2-bit information by using the fluctuation of one notation.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an Internet connection of computers 20, 30 to which an information embedding method and an information reproducing method according to an embodiment of the present invention are applied.

FIG. 2 is a block diagram showing an internal configuration of a computer 20.

FIG. 3 is an explanatory diagram illustrating a configuration of a dictionary database stored in the computers 20, 30.

FIG. 4 is a flowchart of an information embedding program executed by the computer 20.

FIG. 5 is an explanatory diagram illustrating an original text in which information is embedded.

FIG. 6 shows a computer 20 for standardizing original text.
It is an explanatory view of a display screen.

FIG. 7 is an explanatory diagram illustrating a standardized sentence in which an original sentence is standardized.

FIG. 8 is an explanatory diagram illustrating an encrypted text in which information “A” is embedded in a standardized text.

FIG. 9 is a flowchart of an information reproduction program executed by the computer 30.

FIG. 10 is an explanatory diagram of a display screen of a computer 30 in a process of decrypting an encrypted text.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Network 11 ... Keyboard 12 ... Mouse 18 ... Router 20 ... Computer 22 ... CPU 23 ... ROM 24 ... RAM 25 ... Timer 26 ... Display circuit 27 ... Hard disk 29 ... Monitor 30 ... Computer 40 ... Computer

Claims (10)

[Claims] 1. An information embedding device for embedding desired information in a digitized text, based on a predetermined rule, different words and / or notations but words and / or notations representing the same concept. Standardization means for rewriting the sentence into a standard sentence; words and / or words to be rewritten in the standardization process
Or, regarding notation, it is determined which of the word and / or notation representing the same concept is to be used according to the data corresponding to the desired information, and the sentence is rewritten to generate an encrypted sentence in which the data is embedded. An information embedding device comprising: 2. The standardizing means and the embedding means include words and / or embeddings.
2. The information embedding apparatus according to claim 1, wherein the same dictionary database is used as a predetermined rule for rewriting the notation. 3. The information embedding device according to claim 2, wherein the dictionary database has at least one stage of a character, a word, and a phrase as a candidate for rewriting. 4. The information embedding device according to claim 2, wherein the dictionary database is capable of prohibiting use of arbitrary data and / or changing data. 5. The standardization means according to claim 1, further comprising: a difference data generating unit configured to generate difference data based on a difference between the digitized text and the standard text when rewriting the digitized text into a standard text. 1 to Claim 4
An information embedding device according to any one of the above. 6. An information embedding method for embedding desired information in a digitized text, based on a predetermined rule, using different words and / or notations but words and / or notations representing the same concept. A standardization step of rewriting the sentence into a standard sentence, and a word and / or a word to be rewritten in the standardization step.
Or, regarding notation, an embedding step of deciding which of a word and / or notation representing the same concept is to be used in accordance with data corresponding to the desired information, rewriting the text, and embedding the data. Information embedding method. 7. An information decryption device for decrypting data corresponding to the desired information from an encrypted text obtained by the information embedding device according to claim 1, wherein the encryption is performed based on the predetermined rule. An information decoding apparatus, comprising: an extracting unit that extracts a rewritten word and / or a notation of a formatted text; and a decoding unit that decodes the embedded data based on the extracted word and / or notation. 8. The method according to claim 1, wherein the extracting unit includes a rewritten word and / or
8. The information reproducing apparatus according to claim 7, wherein when extracting the notation, the same dictionary database as that used when embedding the data is used. 9. A program for realizing a process of embedding desired information in a digitized text in a computer, based on a predetermined rule, a word and / or a word and / or a notation that represents the same concept even though it is a different word and / or notation. Or, by notation, a function of rewriting the sentence into a standard sentence, and regarding the word and / or notation that is the object of the rewriting, the word and / or notation representing the same concept according to data corresponding to the desired information. And a program for causing a computer to implement a function of rewriting the text and embedding the data by determining which of the above is to be used. 10. A method of handling information for embedding and decoding desired information in a digitized sentence, wherein a word and / or a different word and / or a notation but representing the same concept are written based on a predetermined rule. Or, by notation, a standardization step of rewriting the sentence into a standard sentence, and the words and / or rewritten in the standardization step.
Or, regarding notation, an embedding step of deciding which of a word and / or a notation representing the same concept is to be used in accordance with data corresponding to the desired information, rewriting the text and embedding the data, Receiving an encrypted text in which data is embedded by the process, and extracting a rewritten word and / or notation of the encrypted text based on the predetermined rule; Decoding the embedded data based on the information processing method.