JP2010124355A - Digital watermark reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital watermark reading apparatus for reading out an ID code from a digital watermark embedded in the face printing of commercial goods which is capable of limiting a readout-object range so that only the preliminarily established user can read it out. <P>SOLUTION: The readout-object range which the digital watermark reading apparatus can read out is freely set by reading out an encrypted digital watermark (S12), decrypting it by an encryption key in an IC card set to the digital watermark reading apparatus (S22), verifying the discriminant code included in the decrypted code with a discriminant key in the IC card (S24), and for output of the decrypted results for only "success" (S25). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a reading device that reads a digital watermark from an image and extracts embedded information.

In fields such as product management and distribution management, methods such as reading individual product IDs with handy terminals and managing product information collectively have already been widely used. A typical product ID is a barcode. In addition, digital watermarks have recently attracted attention for such applications.
Since the digital watermark embeds necessary information in an image, for example, a product ID is characterized in that information can be added without interfering with the design of the product and without touching the buyer's eyes.

Various uses of digital watermarks and readers that make use of such features have been conceived. An example of improving the security of a card by reading the digital watermark of a photo part of an ID card (Patent Document 1), or a mobile phone There is an example of configuring a communication terminal having a digital watermark reading function in combination with an image reading and communication function (Patent Document 2).
JP 2001-138673 A JP 2004-179783 A

For example, in Patent Document 2, as an application example, an image with a digital watermark is read by a mobile phone, the ID information database is accessed via a communication means using the extracted ID as a key, and related information is provided to the user. Cite.

In such an application, the ID information embedded in the digital watermark may be read without hiding because of unspecified and wide-ranging services, but on the other hand, it is read within a limited range such as a product serial. Is often desired.
An object of the present invention is to provide a digital watermark reading apparatus for reading a limited range as described above, and an object of the present invention is to realize it in a small and portable form.

In order to solve the above problems, the digital watermark reading apparatus of the present invention provides:
A decryption processing unit that decrypts digital watermark data extracted from an image in which encrypted information is embedded as a digital watermark;
An input unit that captures an image in which the encrypted encryption information is embedded as a digital watermark and inputs it as digital data, and an image that extracts the encrypted information as a digital watermark from the digital data input by the input unit A decryption information obtained by decrypting the encrypted information extracted using the processing means and the key stored in the decryption processing unit is generated, and the discrimination key stored in the decryption processing unit and the discrimination data included in the decryption information And a determination processing unit that outputs a determination result as determination information, a display unit that displays a reading result based on the determination information output from the determination processing unit,
By implementing the above, it is possible to realize a digital watermark reading apparatus that can be read only by a limited user.
In addition, an IC card is used for the decryption process for decrypting the digital watermark data, and the high security level of the IC card and the encryption processing capability are utilized to provide a highly secure digital watermark reader. Features.

According to the present invention, since the reading range can be limited by the discrimination key, an electronic watermark that can be read only by a specific user without being stolen by another person can be provided. In addition, it is possible to operate digital watermarks using the same algorithm for multiple uses and users.
In addition, since the encryption logic can be exchanged by changing the IC card, the user can continue to use the digital watermark reader (and related system) for a long time while switching the encryption logic, thereby reducing the cost of the entire system. It becomes.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of a digital watermark reading apparatus of the present invention.
FIG. 2 is a functional block diagram of the reading apparatus.
The digital watermark reading apparatus in FIG. 1 is a portable type that is intended to be used for merchandise management, and directs an operation button 12 with an imaging unit (not shown in FIG. 1) directed to an image 20 to be read. Read by operating.
2 has a function of optically capturing an image 20 including a digital watermark from the imaging unit 15 and converting the image 20 into image data.
The image processing unit 6 includes a calculation function having a CPU as a core, and is responsible for overall control of the digital watermark reading device 10 such as input / output and signal processing, as well as functions related to image processing such as digital watermark extraction.

The digital watermark extracted by the image processing means 6 is decrypted by the determination processing means 8 with the secret key and collated with the discrimination key according to the procedure described later.
The display means 7 has a display unit 11 composed of a liquid crystal screen or the like, and displays the result of the collation and other information necessary for the operation of the digital watermark reading device 10 on the display unit 11.
The operation button 12 is for transmitting an operation instruction by the user to the information processing unit 16 as an operation signal.

Note that these functions are realized by the CPU of the image processing means 6 executing a preset program.
Although not shown in the figure, it is easy to incorporate communication means such as Bluetooth into the digital watermark reading apparatus 10, and it can be developed for inventory management by connecting with an external host computer or the like.

Further, the digital watermark reading apparatus 10 of the present invention is characterized in that an IC card is used as the determination processing means 8, and the IC card 13 is a small IC card (suitable for mounting on a small device and easily replaceable). The following description will be made using the SIM. Therefore, the form of the IC card 13 in FIG. 1 is also shown in the SIM shape, and the digital watermark reader 10 is provided with an IC card insertion slot 17 for mounting the SIM-shaped IC card.

FIG. 3A shows the appearance of the SIM.
A SIM (Subscriber Identity Module) is generally formed with a long side L1 of about 25 mm and a short side L2 of about 15 mm. The thickness is a uniform thin plate of 1.0 mm or less and usually 0.76 mm.

The original purpose of SIM was developed for the purpose of using mobile phone services, but it has the same function as a credit card-sized IC card, and it is also possible to encrypt and register personal identification information handled by credit card payment, for example It has become. Note that the SIM 31 shown in FIG. 3A is a contact type and has a terminal plate 33, and therefore, the electronic watermark reading apparatus 10 includes a contact pin for contact facing the terminal plate 33.
Since the SIM can be manufactured by the same manufacturing apparatus by the same process as the normal IC card, as shown in FIG. 3B, it is formed on the IC card 35 having the same size and the same shape as the normal IC card. A groove 30m and a fold line 30k are formed around the SIM 31 so that they can be folded from the IC card 35 if necessary. In FIG. 3B, the contact terminal plate 33 is located on the back side of the card.

FIG. 4 shows a block diagram of the SIM. In general, the SIM includes a CPU that controls the entire SIM, a ROM that is a nonvolatile memory, and an EEPROM that is an electrically rewritable nonvolatile memory, and has a communication interface for exchanging information with an external device. The ROM stores a program for operating the CPU, an OS, and the like, and the EEPROM stores parameters, keys, and the like. The basic program and OS installed in the SIM are specially configured for high security and cryptographic processing, and have characteristics suitable for the embodiment of the present invention.

In the SIM 31 related to the digital watermark reading apparatus of the present invention, programs such as the decryption process 381 and the discrimination process 382 are stored in the ROM 38, and data that may be rewritten such as the secret key 391 and the discrimination key 392 is stored in the EEPROM 39. . In the SIM 31, the communication interface 37 is a contact type having a terminal plate 33 as shown in FIG.

FIG. 5 shows an operation flow of the digital watermark reading apparatus of the present invention.
Here, the processing procedure will be described in detail assuming that the reading target is a product ID.
When the operation button 12 is instructed to read from the operation button (S11), the digital watermark reading apparatus 10 takes an image from the imaging unit 15 and converts it into image data (S12).
Next, a digital watermark is extracted by the image processing means 6 from the captured image data. That is, the digital watermark is first separated from the image data including the digital watermark by a predetermined algorithm (S13), and the code information is restored from the digital watermark image (S14). However, the restored code information is in an encrypted state (encrypted information).

The encrypted information is sent to the SIM which is the determination processing means (S15), and decrypted in the SIM. The SIM stores a secret key 391 for decrypting the encrypted information, and this key and the SIM The encryption information is decrypted by the arithmetic function (decryption process 381) (S22), and decryption information is generated. The decryption information is further checked against the discrimination key 392 to determine whether or not the decryption information was to be read.

FIG. 6 shows the relationship between the decryption information and the discrimination key. For example, the decryption information is 2 bytes (16 bits) of data, and the upper 8 bits are discriminated in advance and the lower 8 bits are discriminated in advance. If the data (discrimination ID) 393 is determined (S23), the discrimination process 382 compares the lower 8 bits with the discrimination key 392 (8 bits) to determine “match” or “mismatch” (S24). ).

If the determination result in S24 of FIG. 5 is “match”, the product ID is “valid” and the same ID is transmitted from the SIM (S25, S26). Is transmitted (S27, S26).
From the above result, the image processing means 6 generates information for display from the received code (S16) (S17), and drives the display means 7 to display it (S18).

In this way, it is possible to provide a digital watermark reading apparatus that can be read only by a specified user by encrypting and embedding the product ID and the discrimination ID in the digital watermark and decrypting them with the IC card. In addition, an easily replaceable IC card is easy to change keys and encryption algorithms, and is effective in realizing high security and high convenience.
In the above operation flow, the data length of the digital watermark is 16 bits for the sake of explanation, but the data length can be variously set depending on circumstances such as encryption type and encryption strength. Also, the encryption key is not limited to the secret key method, and may be a public key method.

External view of digital watermark reader Functional block diagram of digital watermark reader External view of SIM SIM block diagram Operation flow diagram of digital watermark reader Diagram showing the state of decryption information and discrimination key

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 Input means 6 Image processing means 7 Display means 8 Judgment processing means 10 Digital watermark reader 11 Display part 12 Operation button 13 IC card 20 Image 31 SIM
33 Terminal board 35 IC card 36 CPU
37 Communication interface 38 ROM
39 EEPROM
381 Decryption processing 382 Discrimination processing 391 Private key 392 Discrimination key

Claims (2)

An electronic watermark reading apparatus having a decryption processing unit for decoding electronic watermark data extracted from an image in which encrypted information is embedded as an electronic watermark, and an image in which encrypted encrypted information is embedded as an electronic watermark Input means for imaging and inputting as digital data;
Image processing means for extracting encrypted information that has become a digital watermark from the digital data input by the input means;
Generate decryption information obtained by decrypting the extracted encryption information using the key stored in the decryption processing unit, and further collate the discrimination key stored in the decryption processing unit with the discrimination data included in the decryption information Determination processing means for outputting the determination result as determination information;
Display means for displaying a reading result based on the discrimination information output from the judgment processing means;
An electronic watermark reading apparatus comprising: The digital watermark reading apparatus according to claim 1, wherein the decryption processing unit is an IC card.

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