JP2011015003A - Password card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a password card capable of correct alignment, without having to depend on only the visual confirmation, when an original image is reproduced from among a plurality of shared images that use a visual cryptographic technique.SOLUTION: Embosses 20 are provided on a shared card (a) and a shared card (b), respectively, and in superimposing both the cards, alignment is executed by mating the embosses to enable correct alignment. Also, alignment can also be executed, by providing a spot-or line-like emboss on either of the cards and allowing the emboss to abut on an end surface of the other card.

Description

  The present invention relates to a personal identification card in which shape information concealed in a state where a recorded image cannot be visually recognized in a normal state is visualized by superimposing a decoding filter.

  2. Description of the Related Art In recent years, in network banking or the like, a method is used in which a random number table card is given to a user and authentication is performed on a network by inputting a number written at a specified position at the time of authentication. However, with the random number table card alone, the contents recorded on the random number table card are used for authentication as they are, and it is difficult to avoid the possibility of snooping or theft. Therefore, in order to further improve confidentiality, the contents are concealed with a single card, but there is a need for a technique that allows the user to visualize the concealed information by using some method.

  There is a visual decryption type encryption technique as one of the techniques for such a request. This is because the original image information is processed into an image that cannot be visually recognized by dispersing it into a plurality of images composed of irregular patterns (called shared images), and the original images are superimposed on each other. The image information is restored to a state in which the image information is visible.

  In FIG. 1, a share image A11 and a share image B12 are generated from an original image 10 (for example, an image having a shape of “T”) by a visual decryption encryption technique, and the share image A11 and the share image B12 are superimposed. It shows how the shape of “T” is restored to a visible state. Here, as an example, the shape of “T” of the restored image 13 is shown as a solid black image.

Various principles have been proposed for the principle of visual decryption encryption technology, share image generation means, and the like. One of them is described in detail in Non-Patent Document 1, for example.
Further, Patent Document 1 discloses a recording medium using visual decryption encryption as a secret information concealing means that replaces a concealing layer, and a technique relating to its creation.

Japanese Patent Laid-Open No. 10-154215

M.Naor andA.Shamir, "Visual Cryptography", Proc. Of Eurocrypt'94 May 1994

  As described above, the visual decryption encryption technology is advantageous in that it can be decrypted by visual manual operation, but on the other hand, since the original image is restored by overlapping a plurality of shared images, There is a weakness that strictness accompanies position accuracy. For example, in the case of FIG. 1, even if there is a slight shift in overlap, a white portion appears in the shape of “T” of the restored image 13, and the difference in density from the background becomes small. There is a problem that it becomes difficult to discriminate.

  Accordingly, an object of the present invention is to provide a personal identification card that can perform accurate alignment without relying only on visual observation when restoring an original image from two shared images using visual decryption encryption technology. .

The present invention for solving the above problems
In the PIN card used to specify the PIN code,
The personal identification card is a pair of a first card and a second card having transparency.
Of the first and second encrypted images generated by the visual decryption type secret sharing method, the first encrypted image is at a predetermined position of the first card and the second encrypted image is the first encrypted image. 2 is formed at a predetermined position of each of the two cards, and the second encryption image is superimposed on the first encryption image on the first and second cards so that the original code can be visually recognized. The positioning means is provided.

The encrypted image is composed of a plurality of areas arranged in a matrix, and one piece of code information is assigned to each area.
Further, at least one of the first card and the second card is provided with address information indicating addresses of the respective areas arranged in the matrix form.
The positioning means is an embossing provided on one of the first card or the second card, and the embossing provided on one card is positioned based on the end face of the other card. Features.

The positioning means may be embossing provided on both the first card and the second card, and the embossing may be fitted and positioned by overlapping the cards.
The second encrypted image is formed as a mirror image on a surface of the second card on the side in contact with the first card, so that the first and second encrypted images can be in close contact with each other. Features.

According to the personal identification card according to the present invention, when an original image is restored using a card paired with a predetermined set, positioning using an emboss formed on the card and the end face of the card, or fitting between the embosses. By means, accurate alignment is possible. Furthermore, when aligning, the film surface on which the share image of the card having visible transparency and the share image of the other card are formed are overlapped with each other without being affected by the thickness of the card. Since these shared images overlap, an image with better visibility can be restored.
In addition, by making code information assigned to areas arranged in a matrix form into an encrypted image by the visual decryption secret sharing method, it is possible to make a PIN card with higher confidentiality, not just a random number table card. .

Conceptual diagram of visual decryption encryption technology External view of PIN card Diagram showing alignment by embossing Diagram showing alignment by fitting Diagram showing embossing Diagram showing how the shared images are superimposed

Hereinafter, the details of the present invention will be described with reference to FIGS.
Hereinafter, the first card is called a share card (a), and the second card is called a share card (b).
FIG. 2 is an external view of the personal identification card according to the present invention, and shows an aspect applied to a random number card.
2A and 2B show a personal identification card in which a share card (a) 21 and a share card (b) 22 are assembled, and FIG. 2C shows a share card in the share card (a) 21. (B) A state in which 22 is overlapped at a predetermined position and a restored image appears.
The share card (a) 21 has a plurality of encryption areas 25 arranged in a matrix and address information 26 indicating addresses of the encryption areas 25. In the encryption area 25, code information encrypted by the visual decryption secret sharing method is arranged in the form of a shared image. The share image (b) 22 is 2, and the share image that is paired with the share image of the share card (a) 21 is arranged in the encryption area 27.
Since the share card (b) 22 has visible transparency, when it is superimposed on the share card (a) 21 at a predetermined position, the code information 28 can be visually recognized together with the address information 26 as indicated by the recovery card 23 at the time of restoration. The code corresponding to the address (number in the example in the figure) can be read.

FIG. 3 is a diagram showing alignment by embossing.
FIG. 3A shows a state in which the share card (b) 22 is superimposed on the share card (a) 21, and a protrusion such as an emboss 20 is provided on the share card (a) 21, and the share card (b) 22 By aligning the end faces, this means that the alignment is simply performed.
3 (B) and 3 (C) are examples of the embossed form shown in the plan view of FIG. 3 (A), FIG. 3 (B) is a line-shaped emboss, and FIG. 3 (C) is a dot shape. This shows the position of the alignment by embossing.

FIG. 4 is a diagram showing alignment by fitting.
FIG. 4D shows the arrangement of the embosses 20 on the card surface, and FIG. 4E is an enlarged cross-sectional view of the embossed portion. As shown in FIG. 4E, since the alignment of the share cards (a) and (b) can be realized by fitting the unevenness, the alignment can be performed with high accuracy without relying only on visual observation.

The embossing for fitting is not limited to the position shown in FIG. 4D, but various patterns are conceivable. However, it is sufficient that at least two embossments are arranged with a distance.
Also, in order to obtain a good quality restored image by alignment by fitting, the registration accuracy of the emboss position and the share image position becomes a problem in card processing. For this purpose, embossing is co-processed (overlapping) Processing at the same time). For example, as shown in FIG. 5, the share image (A) and the share image (B) are accurately positioned, and after superposition, emboss is formed by press working in the superposition state.

FIG. 5 schematically shows one embodiment of embossing.
The basic structure is that the share cards (a) and (b) are overlapped and fixed on a suction cup 51 or the like that also serves as a female mold, and embossed on both cards simultaneously by pressing with a male press mold. As described above, since the alignment of both cards is important in forming the emboss, the embossing in FIG. 5 uses a position control mechanism for accurately overlapping the share card (a) with the share card (a). ing. That is, the control mechanism has a camera 55 that precisely observes the shared images (A) and (B), and calculates an error in the position of the shared images (A) and (B) from the image captured by the camera 55. An X control mechanism 541 for controlling the X direction of the share card (b) and a Y control mechanism 542 for controlling the Y direction are passed through the processing device 53 and the XY control device 54 that performs two-dimensional control to correct the error. The share card (b) can be accurately superimposed on the share card (a).
In the example of FIG. 5, the shared image is used as a detection target for alignment for convenience of explanation, but the target to be photographed by the camera is not limited to the shared image, but a registration mark used for registration. It may be a thing.

FIG. 6 is a diagram illustrating a difference in appearance of the restored image depending on how the shared images are overlapped.
When the share image (B) is superimposed on the share image (A) 11 on the share card (a) 21 shown in FIG. 6 (A) as shown in FIG. 6 (B1), as shown in FIG. 6 (C1). The restored image viewed from an oblique direction has a collapsed pattern (C1 image).
Therefore, as shown in FIG. 6 (B2), when the shared image (A) and the shared image (B) are overlapped so as to be in close contact with each other, the restored image is restored without being destroyed even when viewed from an oblique direction (C2). Figure).

The share card (b) may require about 0.8 mm, which is equivalent to a general card, in order to ensure portability and robustness. The arrangement of the share image (B) shown in 6 (B2) is extremely useful.
To form the shared image (B) in close contact with the shared image (A) as shown in FIG. 6 (B2), the pattern of the shared image (B) is formed on the share card (b) in the form of a “mirror image”. This can be realized by forming.

As described above, it is possible to provide a personal identification card that allows easy alignment of a pair of cards and allows the restored image to be easily viewed regardless of the viewing direction.

The personal identification card of the present invention is not limited to the above embodiments, and various modified embodiments such as the following are also included in the present invention.
(1) The card substrate used in the card of the present invention preferably has embossability, such as polyvinyl chloride resin, amorphous polyethylene terephthalate (PET-G) resin, polycarbonate resin, polylactic acid resin. Etc.
(2) Of the first and second cards constituting the personal identification card of the present invention, the first card (share card (a)) includes an IC and a magnetic recording unit such as a cash card, a credit card, and an ID card. It may be a card having various purposes. The card base of the first card may be transparent or opaque.
(3) In the form of the personal identification card shown in FIG. 2, the address information 26 indicating the address of the personal identification area 25 arranged in a matrix on the first card (share card (a)) is attached. 26 may be provided on the second card (share card (b)).
(4) The address information 26 is provided as visible information in any manner, but the address information 26 may be a shared image. By doing so, only the share image is formed on the first card and the second card, and the address information and the encryption information are restored to be visible only when the two cards are superimposed. By adopting such an aspect, the security is further increased.

10 Original image 11 Share image (A)
12 share image (B)
13 Restoration image 20 Emboss 21 Share card (a)
22 Share card (b)
26 Address information 25, 27 Encryption area 51 Suction cup 52 Press type 55 Camera

Claims (6)

In the PIN card used to specify the PIN code,
The personal identification card is a pair of a first card and a second card having transparency.
Of the first and second encrypted images generated by the visual decryption type secret sharing method, the first encrypted image is at a predetermined position of the first card and the second encrypted image is the first encrypted image. 2 is formed at a predetermined position of each of the two cards, and the second encryption image is superimposed on the first encryption image on the first and second cards so that the original code can be visually recognized. A personal identification card provided with positioning means for allowing   2. The personal identification card according to claim 1, wherein the encrypted image includes a plurality of areas arranged in a matrix, and one piece of code information is assigned to each area.   3. The password card according to claim 2, wherein address information indicating addresses of the respective areas arranged in a matrix is attached to at least one of the first card and the second card.   The positioning means is an embossing provided on one of the first card or the second card, and the embossing provided on one card is positioned with reference to the end face of the other card. The personal identification card according to claim 1.   The positioning means is an embossing provided on both the first card and the second card, and the embossing is fitted and positioned by overlapping the cards. The personal identification card according to any one of 1 to 3. 6. The personal identification card according to claim 1, wherein the second encrypted image is formed as a mirror image on a surface of the second card that is in contact with the first card.

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