JP5445060B2 - Secret sharing method of character information and printed material used therefor - Google Patents

Description

The present invention relates to a secret sharing method for character information and a printed material used for the secret sharing method for character information. More specifically, character information is distributed into two invisible shared images, and one distributed image is formed on the printed material. A secret sharing method for character information in which the other dispersed image is formed on a transparent substrate and the two dispersed images are overlapped to visually restore the character information, and the shared image formed on the printed material is The present invention relates to a secret sharing method for character information that is machine-readable information, and a printed matter used for the secret sharing method for character information.

At first glance, there is disclosed a technique that is a uniform striped pattern, but moire is generated by overlapping predetermined discriminating films, and the latent image is visualized and made visible. It is used for preventing counterfeiting of printed matter (for example, see Patent Document 1).

Also, a machine-readable two-dimensional code that is composed entirely of fine black and white cell patterns and contains a large amount of information in a predetermined area has been put into practical use (described in FIG. 4).

Further, as a means for enhancing security, a visual decryption secret sharing method (VSSS) technique is disclosed (see US Pat. No. 5,488,664 and British Patent No. 2289016).
The visual secret sharing scheme (Visual Secret Sharing Schemes) restores a secret image by collecting k (≦ n) distributed images among n secret images when the secret image is distributed into n encrypted images. It is a technique.
For example, the secret image 1000 represented by “PASS WORD” in FIG. 5 is dispersed into a point drawing image (first share image) 100 and a point drawing image (second share image) 200, and the point drawing is dispersed into two. The original secret image 1000 is restored by superimposing the images 100 and 200.

Also, secret image information is converted into distributed information by VSSS, one distributed image information (shared image) is printed on a medium, and the other distributed image information (shared image) is printed on a transparent substrate, and two distributed images are printed. A method of restoring the secret image information as visible information by superimposing the images has been put into practical use.

JP 2001-213042 A

A service that adds premiums by printing information such as “winning” and “out-of-line” on the ticket face such as admission tickets invisible (states that cannot be recognized as characters without using special media or devices for discrimination) However, tickets such as admission tickets are often filled with necessary items, making it impossible to create a space for adding the above premium information.
Many of these coupons are printed with ultraviolet or infrared absorbing ink to detect counterfeit products such as copies, but the ink cost is high and character information is mechanically recognized. There are issues such as being unable to do so.
Therefore, the present invention disperses character information into two non-visually shareable images, and forms one shared image on a printed material as machine-readable information, and forms the other shared image on a transparent substrate. Then, a secret sharing method of character information for superimposing two dispersed images to restore the character information so as to be visible, and a printed matter used for the method are provided.

In order to achieve the above object, the first aspect of the character information secret sharing method of the present invention is to distribute the imaged character information into two non-visually shareable images by the visual composite secret sharing method. In the secret sharing method of character information that enables the character information to be restored by superimposing two encrypted share images, the one shared image is a two-dimensional code, and the two-dimensional code type to be used A step of creating a two-dimensional code including the character information, a two-dimensional code including the character information as a first share image, and the imaged character information from the first share image Creating a shared image including the second shared image, and at least one of the first shared image and the second shared image is a transparent substrate (hereinafter referred to as a transparent substrate). Forming to say), is characterized in that it has a, a step for restoring the character information according to the first share of the image and the second share of the image by superimposing the image.

The second aspect is characterized in that, in the first aspect, the first share image is formed on an opaque base material, and the second share image is formed on a transparent base material. .

Further, the third aspect is the first or second aspect, wherein the first share image is read by an optical reading device, and the read information and the first share image and the second share image are used. This is characterized in that it can be collated with the character information by the restored image.

The fourth aspect is a printed material used in any one of the first to third aspects, and is characterized in that the first shared image is formed at a predetermined location of the printed material.

1) As in the first aspect of the present invention, the encrypted character information is encrypted by distributing the imaged character information to two non-visible share images, and the two encrypted shares are used. In a secret sharing method of character information that enables character information to be restored by superimposing images, one shared image is set as a two-dimensional code, a two-dimensional code type to be used is determined, and the two-dimensional including the character information Creating a code, and using the two-dimensional code including the character information as a first share image, creating a share image including the imaged character information from the first share image and generating a second share An image, a step of forming at least one of the first share image and the second share image on a transparent substrate (hereinafter also referred to as a transparent substrate), and the first share image A second shared image formed on a transparent substrate from an invisible shared image formed on a printed material Can be restored to visible character information, and characters can be mechanically read from an invisible shared image formed on the printed matter.
Visible character information and optically readable character information can be obtained from one shared image printed on the printed matter, and space saving can be achieved.
2) Also, as in the second aspect, in the first aspect, the first shared image is formed on the opaque base material, and the second shared image is formed on the transparent base material, When one shared image is read by the optical reading device, it becomes easy to read.
3) Further, as in the third aspect, in the first or second aspect, the first share image is further read by an optical reader, and the read information, the first share image, and the second share image are read. By making it possible to collate with the character information based on the image restored from the shared image, the number of “winning tickets” can be mechanically grasped, and this can lead to forgery detection of the printed matter.
4) In addition, as in the fourth aspect, the printed matter is used in any one of the first to third aspects, and the first shared image is formed at a predetermined place of the printed matter, so that it is invisible. Thus, it is possible to visually restore character information from a shared image formed on a transparent base material and to read it mechanically. Furthermore, it is possible to save space in the shared image printing unit.

It is a figure for demonstrating an example of the secret sharing method of the character information of this Embodiment. It is a figure for demonstrating an example of the printed matter used for the secret sharing method of the character information of this Embodiment, and a transparent base material. It is a figure for demonstrating an example of the secret sharing method of the character information of this Embodiment. It is a figure for demonstrating an example of a two-dimensional code. It is a conceptual diagram for demonstrating visual decoding type | formula secret sharing method (VSSS).

The secret sharing method for character information according to the present embodiment uses the visual composite secret sharing method to encrypt the character information that has been imaged into two share images that are not visible. This is a secret sharing method for character information that makes it possible to restore character information based on images by superimposing images.
As a preparation stage, first, character information is imaged. Next, a two-dimensional code type to be used is determined, and a two-dimensional code including the character information is created.
The “two-dimensional code of character information” referred to in the present invention is a pattern in which a plurality of fine squares or circles are arranged in a predetermined area, and characters (alphanumeric, kanji, kana) are combined by adjacent patterns. , Symbols, etc.).
Next, the two-dimensional code that includes the character information is used as a first share image, and a share image that includes the imaged character information is generated from the first share image as a second share image.
The imaged character information may be incorporated only in the second share image described above, or may be incorporated in a distributed manner in the first share image and the second share image.

Form at least one of the first and second shared images on a transparent substrate (the first shared image is formed on an opaque substrate, and the second shared image is formed on a transparent substrate. May be)
In the following description, an example in which a first shared image is formed on an opaque base material (hereinafter simply referred to as a printed material) forming a printed material and a second shared image is formed on a transparent base material will be described.

As a restoration step, the character information by the image is restored by superimposing the second share image formed on the transparent substrate on the first share image formed on the printed material.
Further, the character information is mechanically read from the first invisible shared image formed on the printed matter.

With reference to FIG. 1, an example of a secret sharing method for character information according to the present embodiment will be described.
First, a character (hereinafter also referred to as character information) which is secret information is selected (step 1: hereinafter referred to as S1). The character information that is the secret information is, for example, a hit number (1st, 1st, 2nd, or 2) printed on the admission ticket in an invisible pattern.

Next, a “two-dimensional code type” which is one of the shared images is determined (S2).
There are “PDF417”, “Maxi Code”, “Veri Code”, “Data Matrix”, “QR Code”, and the like that are widely used in the two-dimensional code.
As will be described later, what is shown in FIG. 4 is a “Data Matrix” 11 and a “QR code” 12.
The two-dimensional code shown in FIG. 1 is an image representation of the two-dimensional code, and does not particularly indicate any of the specific examples described above.

Next, a two-dimensional code including the above-described characters is created (S3).
As described later, since the amount of information that can be included in the two-dimensional code is large, implementation period information, service provider information, and the like can be incorporated together with character information.

Next, the character information is imaged (S4). In the following description of the present embodiment, “character” is defined as the numeral “1”.
In this embodiment, the machine reading information is formed in “monochrome” at a low cost, but may be displayed in a color that is a combination of a dropout color (which means a color that is not detected by the machine at the time of machine reading). it can.
The above S1 to S4 are the first preparation stage.

Next, the two-dimensional code including the character information is set as a first share image (S5), and a second share image including the imaged character information is created based on the first share image (S6). .
A pattern image obtained by removing the first share image from the original image including the characters becomes the second share image.

  The above (S5) and (S6) are the shared image creation stage.

The first share image created in S5 is formed on a printed material (S7). The printed matter may be formed by a printer or by printing.
The second share image created in S6 is formed on a transparent substrate (S8).
The formation of the second shared image on the transparent substrate may be performed by ink jet printing or printing ink. The second shared image formed on the transparent substrate may be coated with a protective coating so as not to be rubbed off. Moreover, you may protect by sticking a transparent protective film.

For example, when the first share image is printed on a lottery ticket or an admission ticket and restored at a predetermined lottery hall, a transparent base material is installed (prepared) at the lottery hall. The person who handles the transparent substrate may be a specific person or the person who brought it.
The character image formed on the transparent base material and hidden in the second share image is restored with the first share image printed on the printed material (S9).
The character image may be incorporated into the second share image as described above, or may be incorporated separately from the first share image. In any case, the first shared image formed on the printed material and the second shared image formed on the transparent base material are superimposed to restore the character image by the image (S9).
The first share image printed on the printed material is read as a two-dimensional code by the optical reading device 4 (S10), and the incorporated character information is displayed as visualized character information on the display unit of the optical reading device 4. The

  Since a lot of information can be embedded in the two-dimensional code (first shared image) as described later, in addition to the character information as described above, for example, the period of prize exchange, the contents of the event , The location of the event, and other information that cannot be recovered with a transparent substrate can be embedded together.

With reference to FIG. 2, an example of a printed material used in the secret sharing method for character information according to this embodiment and a transparent substrate will be described.
The printed matter 1 is used for a printed matter that allows the user to discriminate hidden information without incurring much cost, such as a lucky ticket, lottery ticket, admission ticket, lottery, etc., and to secure security.
On the surface of the printed matter 1, although not shown, character information such as a design, a name of what the printed matter is (displaying “admission ticket”), and a usage method of the printed matter is printed finely.
In addition, the first share image 10 is printed or printed by a fine black and white cell pattern including character information (or characters) 3 as machine-readable information in a predetermined place (possible on the back surface) of the printed material 1. ing. Even when the printed portion of the printed matter 1 is printed in full color, the first shared image portion is often formed with a black and white pattern.
In addition, a second shared image 20 having a fine black and white cell pattern similar to that formed on a printed material is formed on the transparent substrate 2 used in the character information secret sharing method of the present embodiment. The second share image 20 is formed by printing or ink jet.

With reference to FIG. 3, an example of the character information secret sharing method of the present embodiment will be described.
When the second share image 20 including a part of the character image of the transparent base material 2 is superimposed on the first share image 10 including a part of the character image described in FIG. The character “1” is restored as the visible character information 3 by an image that cannot be viewed by the shared image 10 and the second shared image 20 alone.

An example of a machine-readable two-dimensional code will be described with reference to FIG.
As the two-dimensional code, “PDF417”, “Maxi Code”, “Veri Code”, “Data Matrix”, “QR code”, and the like are put into practical use, but “Data Matrix” that is relatively frequently used in the present embodiment. And “QR code” will be described.
“Data Matrix” 11 is a two-dimensional code invented by ID Matrix, which can be displayed in a relatively small area, and is used by marking on semiconductor wafers and IC components. An L-shaped alignment pattern and a dotted-line timing cell are arranged, and actual data is placed therein. Since there are L-shaped alignment patterns and timing cells around the periphery, it is easy to recognize the code direction and data cells.
About 2,000 to 3,000 characters can be expressed by a combination of alphanumeric characters.

The QR (Quick Response) code 12 is a code that can be read at a high speed and can be easily restored even when a part is damaged.
The QR code is composed of square position detection patterns (cutout symbols) arranged at three corners (one micro QR), timing patterns, and cells representing data.
The position of the QR code is recognized by searching the above-described position detection pattern, and high-speed reading is possible. Numeric, alphanumeric, kanji, and binary data can be handled, and a combination of alphanumeric characters can represent about 4,200 to 7,000 characters, and kanji can represent about 1,800 characters.

(material)
The transparent substrate on which the second shared image is printed is selected from plastics such as transparent polyester with a thickness of 0.3-2 mm, transparent polycarbonate, transparent polylactic acid, transparent acrylic, and transparent polyvinyl chloride. The In addition, a commercially available inkjet ink or plastic printing ink is used for printing the second shared image.

  The secret sharing method for character information according to the present invention and the printed matter used for this can be used to distinguish hidden information such as lucky tickets, lottery tickets, admission tickets, flyers, lotteries, etc. It can be used for printed materials to be secured.

DESCRIPTION OF SYMBOLS 1 Printed matter 2 Transparent base material, transparent base material 3,1000 Imaged character information, imaged character 4 Optical reader 10,100 First share image 11,12 Two-dimensional code 20,200 Second Share image

Claims (4)

Encrypted by distributing the imaged character information to two non-visible shared images by the visual composite secret sharing method, and making it possible to recover the character information by superimposing the two encrypted shared images In the secret sharing method of character information,
One share image as a two-dimensional code, determining a two-dimensional code type to be used, creating a two-dimensional code including the character information,
A two-dimensional code including the character information as a first share image, and creating a share image containing the imaged character information from the first share image to be a second share image;
Forming at least one of the first share image and the second share image on a transparent substrate; and restoring the character information by the image by superimposing the first share image and the second share image When,
A secret sharing method for character information, comprising: The secret sharing method for character information according to claim 1,
A secret sharing method for character information, wherein the first shared image is formed on an opaque base material and the second shared image is formed on a transparent base material. The secret sharing method for character information according to claim 1 or 2,
Furthermore, the first share image is read by an optical reader, and the read information can be collated with character information based on an image restored from the first share image and the second share image. Secret sharing method for character information. A printed matter used in the secret sharing method for character information according to claim 1,
A printed material used in a secret sharing method for character information, wherein a first shared image is formed at a predetermined location of the printed material.

Images