JP2005192148A - Document creating apparatus for verifying alteration, alteration detecting apparatus, document creating method for verifying alteration, alteration detecting method, document creation program for verifying alteration, alteration detection program, and recording medium for storing the programs - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a document creation technique for alteration verification, capable of more easily detecting alteration, by embedding information in the background of an image in a printing document, and to provide a verification method. <P>SOLUTION: The document creation technique includes a means 111 for acquiring a document image to be processed for acquiring an image to be processed; an optional information acquisition means 112 for acquiring optional information; an arbitrary information superimposition means 113 for generating an image, where the optional information acquired by the arbitrary information acquisition means is superimposed on the image acquired by the means for acquiring the document image to be processed; and a verification information superimposing means 114 for generating image information for alteration verification, where verification information is superimposed on the image generated by the arbitrary information superimposing means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to falsification verification technology for printed materials. In particular, with regard to print creation technology and verification technology that supports tampering verification, a falsification verification document creation device, a falsification detection device, and falsification that can more easily detect tampering by embedding information in the background of an image of a printed document The present invention relates to a verification document creation, a falsification detection method, a falsification verification document creation program, a falsification detection program, and a recording medium in which these programs are stored.

  The “printed material verification information creation device and printed material verification device” described in Patent Document 1 discloses a method for converting a printed material into a printed material corresponding to tampering verification. In this method, dependency information dependent on a printed material is printed as verification information on the printed material in a form such as a barcode, and when verifying, the printed material and the dependency information read from the printed material are collated.

  In addition, the “apparatus, system, method, program, printed material, and recording medium related to addition of printed material verification information and printed material verification” described in Patent Document 2 includes means for preventing falsification of the content of the printed material and confirming uniqueness at the same time. Is provided.

Further, “Form Non-Falsification Verification Method, Form Printing Device, and Form Tampering Existence Verification Device” described in Patent Document 3 discloses a form falsification verification method and a falsification verification device. In this method, a form image is coded in a reproducible format, further recorded in a form in a predetermined recording format, and when verifying, the form image and the form image reproduced from the code are visually compared. Validate.
JP-A-8-297743 JP 2002-99209 A JP 2002-298120 A

  However, the technique disclosed in Patent Document 1 is intended for what has already been printed, and does not support generation of printed data originally corresponding to digital data as falsification verification.

  In addition, since the technology of Patent Document 2 uses ID paper that outputs ID information in response to radio waves, it cannot be easily produced at low cost a printed material corresponding to tampering verification.

  Furthermore, since the technique of Patent Document 3 is verified visually, it cannot be said that productivity is high, and is not suitable for a case where a large amount of printed matter is verified in a short time.

  It is an object of the present invention to provide a technique for creating a printed material that can be verified whether the contents have been tampered with, and a technique for verifying tampering. In particular, it is an object of the present invention to provide a print document creation technique and a verification technique that enable detection and suppression of forgery using a creation apparatus and prevention of key decryption using a verification apparatus.

  The falsification verification document creation apparatus of the present invention includes a processing target document image acquisition unit that acquires an image to be processed, an arbitrary information acquisition unit that acquires arbitrary information, and the image acquired by the processing target document image acquisition unit. In addition, arbitrary information superimposing means for generating an image in which the arbitrary information acquired by the arbitrary information acquiring means is superimposed, and falsification verification image information in which verification information is superimposed on the image generated by the arbitrary information superimposing means are generated. And verification information superimposing means.

  In the falsification verification document creation apparatus according to the present invention, the arbitrary information can be a print date and time of the falsification verification document.

  In the falsification verification document creation apparatus of the present invention, the arbitrary information can be the printer information of the falsification verification document.

  In the falsification verification document creation apparatus of the present invention, the arbitrary information is obtained by encrypting the key used when creating the falsification verification document with the public key of the person or organization who wants to perform the verification. Can do.

  The falsification verification apparatus according to the present invention includes an image acquisition unit that acquires a print document to be verified as an image, an arbitrary information extraction unit that extracts arbitrary information from the image acquired by the image acquisition unit, and an image acquisition unit that acquires the information. Whether the contents of the printed matter and the superimposed arbitrary information are falsified depending on whether the verification information extraction means for extracting the verification information from the image and the verification information extracted by the verification information extraction means have predetermined characteristics A tampering verification unit that verifies whether or not, and a verification result output unit that outputs a result verified by the tampering verification unit.

  The falsification verification document creation method of the present invention includes a processing target document image acquisition step for acquiring an image to be processed, an arbitrary information acquisition step for acquiring arbitrary information, and the image acquired in the processing target document image acquisition step. In addition, an arbitrary information superimposing step for generating an image in which the arbitrary information acquired in the arbitrary information acquiring step is superimposed, and falsification verification image information in which verification information is superimposed on the image generated in the arbitrary information superimposing step are generated. And a verification information superimposing step.

  In the falsification verification document creation method of the present invention, the arbitrary information can be the print date and time of the falsification verification document.

  8. The falsification verification document creation method according to claim 6, wherein the arbitrary information is printer information of a falsification verification document.

  In the falsification verification document creation method of the present invention, the arbitrary information may be encrypted with the public key of the person or organization that wants to perform the verification, and the key used when creating the falsification verification document. it can.

  The falsification verification method of the present invention includes an image acquisition step for acquiring a print document to be verified as an image, an arbitrary information extraction step for extracting arbitrary information from the image acquired in the image acquisition step, and an acquisition in the image acquisition step. Whether the contents of the printed matter and the superimposed arbitrary information are falsified depending on whether the verification information extraction step for extracting verification information from the image and whether the verification information extracted by the verification information extraction means has predetermined characteristics It is characterized by comprising tampering verification means for verifying whether or not and a verification result output step for outputting the verification result verified in the tampering verification step.

  The falsification verification document creation program of the present invention can execute the steps in the falsification verification document generation method, and the falsification verification program of the present invention can execute the steps of the falsification verification method.

  The recording medium of the present invention stores the falsification verification document creation program and the falsification verification program.

  (1) Tampering can be detected more easily by embedding information in the background of an image of a printed document.

  (2) The printed date and time can be extracted from the falsification verification document. In particular, by repeatedly embedding the entire document in a form that is difficult to understand visually, even when a part of the document has been tampered with, information on the printing date and time can be reliably extracted. Thus, for example, if the print date and time extracted from the falsification verification document printed one year ago is yesterday, it can be determined that the falsification verification document may be a forged document.

  (3) A printed person can be created from a falsification verification document. In particular, by repeatedly embedding the entire document in a form that is difficult to understand visually, even if a part of the document has been tampered with, it is possible to reliably extract the printed person information. Thereby, it is possible to prevent impersonation of a printed person and to specify a forged person.

  (4) According to the present invention, since the persons or organizations that can perform verification can be limited, it is possible to prevent an attack such as decryption of a key using a verification apparatus by an unauthorized person.

  (5) It is possible to generate a print document in which information necessary for detection and prevention of forgery of the print document and prevention of attacks such as key decryption are embedded. Furthermore, it is possible to generate a print document that can detect falsification of the embedded arbitrary information itself.

Embodiments of the present invention will be described below.
Embodiment 1
In the first embodiment, not only information for verifying tampering but also printing date information can be embedded in a print document to detect tampering (or forgery) and to suppress tampering. Can do.

  First, a recording medium storing a falsification verification document creation apparatus, a falsification verification document creation method, a falsification verification document creation program, and a falsification verification document creation program according to this embodiment will be described.

  1A is a functional block diagram of the falsification verification document creation apparatus, and FIG. 1B is a hardware block diagram of the falsification verification document creation apparatus.

  1A, the falsification verification document creation apparatus 1 includes a processing target document image acquisition unit 111, an arbitrary information acquisition unit 112, an arbitrary information superimposition unit 113, a verification information superimposition unit 114, and a printing unit 115. It is comprised including. 1B, the falsification verification document creation device 1 includes a CPU 121, a ROM 122, a RAM 123, a keyboard 124, a hard disk 125, a printer 126, an image scanner 127, and a communication circuit 128. It consists of The RAM 123 stores a processing target document image acquisition program (scanner program, communication program, etc.), an arbitrary information acquisition program, an arbitrary information superimposition program, a verification information superimposition program, and a printing program. These programs constitute the falsification verification document creation program of the present invention. Each of these programs cooperates with the CPU 121 (or further cooperates with other components) to process the document image acquisition unit 111, the arbitrary information acquisition unit 112, the arbitrary information superimposition unit 113, and the verification information superimposition unit 114. And the printing means 115. Each program can be stored in a recording medium such as a floppy disk or a magneto-optical disk and distributed.

  The document image to be processed for creating the falsification verification document can be acquired by the image scanner 127 in FIG. 1B, or can be acquired by the communication circuit 128 in FIG. 1B through the network or the public line. It can be acquired from a device, can also be acquired from the hard disk 125 in FIG. 1B, and can also be acquired from an application such as a word processor.

  The operation of the falsification verification document creation apparatus 1 shown in FIG. First, the processing target document image acquisition unit 111 acquires the processing target document image DG shown in FIG.

  The arbitrary information acquisition unit 112 can acquire, for example, arbitrary information such as the printing date, the name of the creator, and the creation location from the keyboard 124 or the like. For example, when the arbitrary information is a printing date, the printing date is encoded with a sequence of “0” and “1”. For example, as shown in FIG. 3, the year and month can be represented by 4 bits, the day can be represented by 5 bits, and the entire year, month and day can be represented by 13 bits.

  The arbitrary information superimposing unit 113 defines all or part of the image acquired by the processing target document image acquiring unit 111 as a processing region A, and divides the processing region A into a plurality of rectangular regions. Some of these rectangular areas include character strokes (including all or part of characters) and others do not. In this case, whether or not the stroke of the character is included in the predetermined area can also be determined by whether or not a black pixel connected component having a predetermined length exists in each rectangular area.

  The arbitrary information superimposing means 113 embeds the above-described arbitrary information in at least two areas that do not include a character stroke (not including a part of the character). Thereby, even if there is alteration, arbitrary information can be extracted. In particular, by embedding arbitrary information in all areas in the processing area A that do not include characters, it is possible to detect with high accuracy even for some tampering, and less affected by dirt (strong against dirt). High-precision detection is possible.

  As shown in FIG. 4 (processing area A), with respect to the bit string indicating the printing date (“0011011101101” in the example of FIG. 4), if “1”, there is a dot (indicated by a black circle in FIG. 4), “0 ", There is no dot (however, it is indicated by a white circle in FIG. 4) and the dots are arranged from the upper left to the lower right of the rectangular area. In FIG. 4, five rectangular areas A1 to A5 are displayed, and the rectangular area A1 and the rectangular area A5 do not include character strokes. Therefore, the same arbitrary information (printing date is displayed in the two rectangular areas. Each bit string is embedded.

  This arbitrary information is formed in a portion corresponding to 13 dots in FIG. 4 (hereinafter, “arbitrary information portion”). For example, a bit string “0001110010110” representing the printing date is displayed in the row a11 of the rectangular area A1. The first 5 bits are embedded, the next 5 bits are embedded in row a12, and the remaining 3 bits are embedded in row a13. The same dot pattern as that of the rectangular area A1 is embedded in the rectangular area A5. The processing area A is defined as A1 to A5 in the above example, but the processing area A can be further expanded to the left side, right side, upper side, and lower side of A1 to A5.

  Next, the verification information superimposing means 114 embeds the falsification verification information for the processing area A (area consisting of the rectangular areas A1 to A5) as shown in FIG. In the present embodiment, as the verification information, information in which the number of dots in the processing area A is an even number or an odd number is employed (see Japanese Patent Application No. 2002-367853).

  That is, the verification information superimposing unit 114 embeds verification information for verifying further tampering in the processing area in which the dot is embedded by the arbitrary information superimposing unit 113. In the present embodiment, random numbers “0” or “1” are separately generated for the rectangular areas A1 to A5, and the number of dots in each rectangular area is an even number if the random number is “0”, and an odd number if the random number is “1”. Adjust so that Here, the random number is generated from a key which is secret information. In FIG. 5, random numbers “0”, “1”, “0”, “0”, “1” are assigned to the rectangular areas A1 to A5. Accordingly, the number of dots in the rectangular areas A1 to A5 is adjusted to be even, odd, even, even, or odd.

  First, for the rectangular area A1, since eight dots are already embedded in the portion representing the arbitrary information (see FIG. 4), the dots are arranged at regular intervals in the blank portion excluding the arbitrary information portion, and the number of the dots is as follows. Adjust to an even number. In FIG. 4, for convenience of explanation, a blank portion between 8 dots is indicated by white dots.

  In the example of FIG. 5, the twelve dots shown in FIG. 4 are arranged in the blank area of the rectangular area A1. In FIG. 5, these dots are densely arranged in the arbitrary information portion. However, for example, every other dot can be formed. Since the rectangular areas A2, A3, and A4 include character strokes, the dots are arranged so that the total number of dots is odd, even, and even so as not to overlap with the strokes. In FIG. 5, the dots in the rectangular areas A2 to A4 are densely arranged in a portion that does not overlap with the stroke. However, for example, every other dot may be formed.

  Since the random number “1” is set for the rectangular area A5, dots are arranged so that the number of dots is an odd number as in the rectangular area A1.

  The number of dots can be adjusted by setting dots and then deleting the dots as much as possible.

  As described above, the falsification verification image DD as shown in FIG. 6 in which the verification information is embedded is created, and this image DD is printed by the printing unit 115.

  Next, a falsification detection device, a falsification detection method, a falsification detection program, and a recording medium storing the program will be described.

  FIG. 7A is a functional block diagram of the falsification verification apparatus, and FIG. 7B is a hardware block diagram of the falsification verification apparatus.

  In FIG. 7A, the tampering verification apparatus 2 includes an image acquisition unit 211, an arbitrary information extraction unit 212, an arbitrary information extraction unit 213, a tampering verification unit 214, and a verification result display unit 215. ing. 7B, the falsification verification device 2 includes a CPU 221, a ROM 222, a RAM 223, a hard disk 224, a display 225, an image scanner 226, and a communication circuit 227. The RAM 223 stores an image reading program (scanner program, communication program, etc.), an arbitrary information extraction program, an arbitrary information extraction program, a falsification verification program, and a verification result output program. Each of these programs constitutes the document verification program of the present invention, and cooperates with the CPU 221 (or further cooperates with other components) to acquire the image acquisition means 211, arbitrary information extraction means 212, arbitrary information extraction means 713, It functions as a falsification verification unit 214 and a verification result display unit 215. Each program can be stored in a recording medium such as a floppy disk or a magneto-optical disk and distributed.

  The document image to be verified can be acquired by the image scanner 226 in FIG. 7B, or can be acquired from another device via the network or public line by the communication circuit 227 in FIG. 7B. It can also be acquired from the hard disk 224 in FIG. 7B, and can also be acquired from an application such as a word processor.

  Hereinafter, the operation of the tampering verification apparatus 2 shown in FIG. 7A will be described by taking as an example the case where the document image to be verified is a printed matter.

  First, a document image to be verified is acquired by the image acquisition unit 211 (image scanner 226). The arbitrary information extraction unit 212 divides the entire acquired image into rectangular areas as in the creation. Then, print date information embedded as arbitrary information is extracted from an area that does not include a character stroke. It is checked by the falsification verification means 214 whether the extracted print date information has been falsified. The verification information extraction unit 213 extracts the number of dots embedded in each area as verification information.

  Here, as shown in FIG. 8A, a case where the printing date and time is embedded in the rectangular areas A1 and A5 and tampering is performed for each printing date and time is taken as an example. In this example, it is assumed that the amount of money “¥ 10,000” has been altered to “¥ 50,000”, and at this time, the rectangular area in which the printing date and time are embedded is copied. The original amount is not listed.

  The falsification verification unit 214 first generates a random number of “0” or “1” for each region using the time of creation and the key. Then, the alteration verification is determined by whether or not the even or odd number of dots in each region matches the even or odd number of the random number.

  In the example of FIG. 8B, since the rectangular areas A3 and A4 fail (does not match the random number) as indicated by the circled numbers 1 and 2, it can be determined that the area has been tampered with. Also, it can be determined that the print date information embedded in the areas A1 and A5 that do not include the character stroke is not authentic. That is, when it is determined that any of the areas A1 to A5 has been tampered with, the extracted print date information may have been tampered with. Therefore, the print date information extracted from the area that has been tampered with is discarded, and the print date information extracted from the area that has not been tampered with (area not shown in FIG. 8A).

  The verification result display unit 215 displays the extracted print date on the display 225 and the like together with the document image in which the falsified portion is emphasized. By confirming the displayed print date, it can be determined whether or not the print document to be verified has been forged.

  Further, not only the printing date but also the name and affiliation of the person who performed printing can be embedded in the same manner.

In the above example, it is possible to detect falsification of the amount of money, and information relating to the falsified document remains without being lost. Therefore, even if the document is altered, it is possible to easily identify what kind of document the original was.
<< Embodiment 2 >>
For the document image for falsification verification, a person or organization having the authority to perform verification can be set for each document image. A situation in which a distributed document image for verifying tampering can be verified by any number of people is not desirable in terms of security. In the crypto world, in general, security is often secured by keeping information called keys secret, but there is a possibility that attacks that try to know key values (codes) etc. will be performed by repeatedly performing verification actions There is.

  In the second embodiment, a key K encrypted with the public key k1 of the person or organization can be embedded as arbitrary information in order to limit the person or organization having the authority to perform verification.

  FIG. 9 shows an example where the document image creator A for falsification verification designates B as the verifier.

  The creator A uses the falsification verification document creation device 31 to create the falsification verification document D1. At this time, B is designated as the verifier. The document creation apparatus 31 obtains B's public key from the public key management center 32. Then, the key K is encrypted using the public key k1 of B, and this is embedded in the image in the same manner as the method described in the first embodiment. Further, verification information for verifying tampering is embedded, and a tampering verification document is generated.

  In the case of verification, first, the verifier B passes his / her private key k2 to the falsification verification device 33. The falsification verification device 33 extracts the encrypted key K embedded in the verification target image D2, and decrypts it using the B private key k2. The falsification verification device 33 acquires a key K necessary for verification. If the secret key k2 is not correct, it cannot be decrypted and the key K cannot be acquired. Since only B owns B's private key k1, this means that only B can obtain the key K required for verification. Then, tampering is verified using the acquired key. As described above, it is possible to create and verify a falsification verification document in which a verifier is limited.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of Embodiment 1 of the present invention, where (A) is a functional block diagram of a falsification verification document creation device, and (B) is a hardware block diagram of a falsification verification document creation device. It is a figure which shows the image used as the process target in Embodiment 1 of FIG. It is the figure which represented the date in the bit string which shows the specific example of verification information. It is a figure which shows a mode that the printing date of FIG. 3 has been arrange | positioned in the rectangular area. It is a figure which shows a mode that the falsification verification information was embedded about the process area by the verification information superimposing means. It is a figure which shows the image which embedded the verification information. (A) is a functional block diagram of the falsification verification device, and (B) is a hardware block diagram of the falsification verification device. 4A and 4B are explanatory diagrams showing falsification verification processing, in which FIG. 4A shows a state where a part of a document image before falsification is to be tampered with, and FIG. 4B shows a part of the document image after falsification. It is. It is a figure which shows an example of a system in case the creator of a falsification verification document designates another person as a verifier.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Falsification verification document preparation apparatus 2 Falsification verification apparatus 111 Processing object document image acquisition means 112 Arbitrary information acquisition means 113 Arbitrary information superimposition means 114 Verification information superimposition means 115 Printing means 121,221 CPU
122,222 ROM
123,223 RAM
124 Keyboard 125, 224 Hard disk 126 Printer 127, 226 Image scanner 128, 227 Communication circuit 211 Image acquisition means 212 Arbitrary information extraction means 213 Arbitrary information extraction means 214 Falsification verification means 215 Verification result display means 225 Display

Claims (14)

Processing target document image acquisition means for acquiring an image to be processed;
Arbitrary information acquisition means for acquiring arbitrary information;
Arbitrary information superimposing means for generating an image obtained by superimposing the arbitrary information acquired by the arbitrary information acquiring means on the image acquired by the processing target document image acquiring means;
Verification information superimposing means for generating falsification verification image information in which verification information is superimposed on the image generated by the arbitrary information superimposing means;
A document creation device for falsification verification, comprising:   The falsification verification document creation apparatus according to claim 1, wherein the arbitrary information is a print date and time of a falsification verification document.   3. The falsification verification document creation device according to claim 1, wherein the arbitrary information is printer information of a falsification verification document.   4. The arbitrary information according to claim 1, wherein the arbitrary information is a public key of a person or organization who wants to perform verification, and is obtained by encrypting a key used when creating a falsification verification document. Document creation device for falsification verification described in 1. Image acquisition means for acquiring a print document to be verified as an image;
Arbitrary information extracting means for extracting arbitrary information from the image acquired by the image acquiring means;
Verification information extraction means for extracting verification information from the image acquired by the image acquisition means;
Falsification verification means for verifying whether or not there is any falsification in the contents of the printed matter and the superimposed arbitrary information depending on whether the verification information extracted by the verification information extraction means has a predetermined characteristic;
Verification result output means for outputting the result verified by the falsification verification means;
A tamper verification device characterized by comprising: A processing target document image capturing step for acquiring an image to be processed;
An arbitrary information acquisition step of acquiring arbitrary information;
An arbitrary information superimposing step for generating an image in which the arbitrary information acquired in the arbitrary information acquiring step is superimposed on the image acquired in the processing target document image acquiring step;
A verification information superimposing step for generating falsification verification image information in which verification information is superimposed on the image generated in the arbitrary information superimposing step;
A method for creating a falsification verification document, comprising:   7. The falsification verification document creation method according to claim 6, wherein the arbitrary information is a print date and time of a falsification verification document.   8. The falsification verification document creation method according to claim 6, wherein the arbitrary information is printer information of a falsification verification document.   9. The optional information according to claim 6, wherein the arbitrary information is a public key of a person or organization who wants to perform verification, and is obtained by encrypting a key used when creating a falsification verification document. Document creation method for falsification verification described in 1. An image acquisition step for acquiring a print document to be verified as an image;
An arbitrary information extracting step of extracting arbitrary information from the image acquired in the image acquiring step;
A verification information extraction step of extracting verification information from the image acquired in the image acquisition step;
Falsification verification means for verifying whether the contents of the printed matter and the arbitrary information superimposed are falsified by whether the verification information extracted by the verification information extraction means has predetermined characteristics;
A verification result output step for outputting the verification result verified in the falsification verification step;
A tamper verification method characterized by comprising:   A program for creating a falsification verification document, wherein the steps according to claim 6 are executed.   11. A falsification verification program that executes each step according to claim 10.   A computer-readable recording medium storing the falsification verification document creation program according to claim 11.   A computer-readable recording medium storing the falsification verification program according to claim 12.

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