JP7415671B2 - Information processing program, information processing device, and information processing method - Google Patents

Description

The present invention relates to an information processing program and the like.

In recent years, methods for counterfeiting QR codes (registered trademarks) have been devised, and detection of counterfeiting has become a common issue in the QR code industry. Regarding a QR code forgery method, a probabilistic QR code forgery technique was devised in June 2018 (for example, see Non-Patent Document 1). The QR code here refers to an encoding method in which digital data is expressed in black and white dot patterns arranged vertically and horizontally on a plane. FIG. 6 is a diagram showing a reference example of a counterfeit QR code. As shown in Figure 6, by embedding dots at predetermined positions in a normal QR code, normal decrypted data will be redirected to the URL (Uniform Resource Locator) of a malicious website as incorrect decrypted data with a certain probability. Decrypted. As a result, cyber attacks become possible.

The QR code uses an error correction code technique called a Reed Solomon (RS) code. Error correction code technology can correct errors even if there are several bit errors in read data, allowing for normal decoding. A limit value called error correction ability is set for the number of bits that can correct errors. In the decoding process, read data can be decoded into normal data if the number of noises is within the error correction ability. For example, normal decrypted data indicates the URL "http://www.aaaaaaa.com/".

On the other hand, in the decoding process, if the number of noises in the read data exceeds the error correction ability, a read error occurs. Here, a special type of noise has been reported in which the noise is either unreadable or unreadable during the decoding process. In the decoding process, when a QR code containing a special type of noise is read, normal decoded data and abnormal decoded data are generated stochastically depending on the reading result. A QR code that includes such a special format is called a QR code that transitions stochastically. If a malicious person decodes incorrect data each time, he or she will notice the forgery, so they forge such a QR code that probabilistically transitions between normal decrypted data and incorrect decoded data. For example, if noise is embedded in a special format to decode the URL "http://www.aabaaaa.com/" as abnormal decoded data, the decoding process will be completed if the number of noises is within the error correction capability. This may result in incorrect data being decoded.

For such QR code forgery, a forgery determination method is known in which the number of error correction bits during decoding is counted, and if the number is equal to or greater than a threshold value, the code is determined to be a forgery. The threshold value indicates, for example, a value of error correction ability times 0.8.

Okuma, Takita, Morii, “The existence of QR codes that lead to malicious sites and counterfeit attacks using them,” IEICE Technical Report, vol. 118, no.109, ICSS2018-6, pp.33-38, June 2018

However, in determining a QR code that transitions probabilistically, there is a problem in that a non-forged QR code is incorrectly determined to be a forged QR code that transitions stochastically. For example, assume that when the error correction ability is 5, the threshold for determining forgery is error correction ability x 0.8. That is, assume that the threshold value is 4. Then, in the conventional determination process, if the number of error correction bits is 4, it is determined that it is a forgery. However, if the QR code is contaminated, such as dirt or tear, the number of error correction bits becomes 4 or more, and the QR code may be erroneously determined to be a forgery even though it is not a forgery.

One aspect of the present invention is to avoid erroneously determining that a QR code that is not a forgery is a forgery in determining a QR code that changes stochastically.

In the first proposal, the information processing program weights each block according to the probability that each block included in the QR code to be processed will be modified, and blocks the weighted blocks. A computer is caused to execute a process of determining whether or not the QR code is a QR code that changes stochastically according to the number of error bits included in the QR code.

According to one embodiment, in determining a QR code that changes stochastically, it is possible to avoid erroneously determining that a QR code that is not a forgery is a forgery.

FIG. 1 is a diagram showing the functional configuration of an information processing apparatus according to an embodiment. FIG. 2 is a diagram showing an example of the code arrangement of the QR code (2-M type). FIG. 3 is a diagram showing an example of a code word of a 2-M type QR code. FIG. 4 is a diagram illustrating an example of a flowchart of determination according to the embodiment. FIG. 5 is a diagram illustrating an example of a computer that executes an information processing program. FIG. 6 is a diagram showing a reference example of a counterfeit QR code. FIG. 7 is a diagram illustrating a reference example in which it is erroneously determined to be a forgery.

Embodiments of an information processing program, an information processing apparatus, and an information processing method disclosed in the present application will be described in detail below based on the drawings. Note that this invention is not limited to the examples.

First, a reference example in which an erroneous determination as a forgery is made will be described with reference to FIG. FIG. 7 is a diagram illustrating a reference example in which it is erroneously determined to be a forgery. Note that the error correction capability is assumed to be 5. It is assumed that the threshold value for determining forgery is 5×0.8 (=4). Assume that the number of error correction bits of the QR code as shown in the upper diagram of FIG. 7 is 4. Then, in the decoding process, since the number of error correction bits is greater than or equal to the threshold value, the decoding process determines that it is a forgery. Further, it is assumed that the number of error correction bits of a QR code with stains as shown in the lower diagram of FIG. 7 is 4. Then, in the decoding process, since the number of error correction bits is equal to or greater than the threshold value, the image is erroneously determined to be a forgery even though it is not a forgery. This is because, for example, error bits that occur when reading a QR code are also counted. Note that although the QR code shown in the lower diagram of FIG. 7 is soiled, it may also be soiled with tears or the like.

Therefore, in the following embodiments, an information processing apparatus that avoids erroneously determining a QR code that is not a forgery as a forgery when determining a QR code that changes probabilistically will be described.

FIG. 1 is a diagram showing the functional configuration of an information processing apparatus according to an embodiment. The information processing device 1 shown in FIG. 1 takes advantage of the fact that there are parts of the QR code that are likely to be used for counterfeiting, and calculates the number of error bits included in the parts that are likely to be used for counterfeiting. , it is determined whether the QR code is a QR code that changes stochastically.

As shown in FIG. 1, the information processing device 1 includes a control section 10 and a storage section 20.

The control unit 10 corresponds to an electronic circuit such as a CPU (Central Processing Unit). The control unit 10 has an internal memory for storing programs and control data that define various processing procedures, and executes various processes using these. The control section 10 includes a reading section 11 , an error correction location specifying section 12 , a weighting section 13 , a forgery determining section 14 , and a decoding section 15 . Note that the weighting unit 13 is an example of a weighting unit. The forgery determination unit 14 is an example of a determination unit.

The storage unit 20 is, for example, a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, or a storage device such as a hard disk or an optical disk. The storage unit 20 has a threshold value 21. The threshold value 21 indicates a constant value used to determine forgery.

The reading unit 11 reads the QR code using a decoder. Note that the decoder may be a dedicated application that recognizes QR codes, or may have a reading function using hardware such as a camera.

The error correction location specifying unit 12 identifies the error correction location of the QR code read by the reading unit 11. For example, the error correction location specifying unit 12 uses the RS code to detect errors from the read image of the QR code, and corrects the detected errors. Then, the error correction location identification unit 12 identifies the location where the error has been corrected.

When determining a QR code that changes stochastically, the weighting unit 13 weights each block included in the QR code according to the probability that each block will be modified. For example, if the block included in the QR code has a probability of 1/2 or more of being used for forgery, the weighting unit 13 weights the block.

Here, an example of the code arrangement of the QR code will be explained with reference to FIG. 2. FIG. 2 is a diagram showing an example of the code arrangement of the QR code (2-M type). As shown in FIG. 2, the portion indicated by "E" is an error correction block. The part indicated by "D" is an information code. It is known that a portion with a high probability of being used in a QR code that changes stochastically is an error correction block indicated by "E". This is because if the part of the information code indicated by "D" is forged, it will always be forged. Therefore, in the code arrangement of the QR code, the error correction block indicated by "E" is a part that has a high probability of being used for a QR code that changes stochastically. Here, the emphasized pattern part of the QR code arrangement in FIG. 2 is an error correction block indicated by "E", and is a part that has a high probability of being used for a QR code that changes stochastically.

Here, an example of a code word of a 2-M type QR code will be explained with reference to FIG. 3. FIG. 3 is a diagram showing an example of a code word of a 2-M type QR code.

As shown in FIG. 3, the code word of the QR code includes an information code, a padding code, and an error correction block. Assume that "http://www.aaaaaaa.com/" is embedded in the QR code as a URL. In such a case, the information code is converted by converting "http://www.aaaaaaa,com/" into a Shift JIS 1-byte code, adding a mode indicator and a character count indicator in front of the converted data, and converting it. A termination pattern is added after the obtained data, and the resulting data is divided into 8 bits. Note that the mode indicator is an identifier indicating the type of character data (numeric mode, alphanumeric mode, 8-bit byte mode, kanji mode) that can be embedded in the QR code. Here, as an example, a bit string indicating an 8-bit byte mode is set in the mode indicator. The character count indicator is a bit string that defines the length of the data string embedded in the QR code. Here, as an example, a bit string (00010110) indicating 22 characters is set as the character count indicator.

The filler code is a temporary code word embedded that does not represent data until the total data amount is reached when the total data amount of the QR code is less than the total data amount. Note that the padding code is repeatedly padded with 236 (11101100) and 17 (00010001) as a fixed bit pattern. The information code and the filler code are QR code data, and are encoded using the RS code.

The error correction block is information that can correct errors in QR code data and decode it. This error correction block is the block indicated by "E" in the code arrangement of the QR code shown in FIG. 2, and is a part that has a high probability of being used for a QR code that changes stochastically.

Returning to FIG. 1, the forgery determination unit 14 determines whether or not the QR code is a QR code that probabilistically transitions according to the number of error bits included in a block that is likely to be modified. The unit 14 counts the number of error bits included in the blocks weighted by the weighting unit 13 with respect to the error correction location identified by the error correction location identification unit 12. Then, the forgery determination unit 14 determines whether the counted number exceeds the threshold value 21 or not. That is, if the counted number exceeds the threshold value 21, the forgery determination unit 14 determines that the QR code is a QR code that changes probabilistically. That is, the forgery determination unit 14 detects the read QR code as a forged code. Further, if the counted number is less than or equal to the threshold value 21, the forgery determination unit 14 determines that the QR code is not a QR code that transitions probabilistically.

The decoding unit 15 decodes the QR code if it is not a QR code that changes stochastically.

[Judgment flowchart]
Here, an example of a flowchart of determination according to the embodiment will be described with reference to FIG. 4. FIG. 4 is a diagram illustrating an example of a flowchart of determination according to the embodiment.

As shown in FIG. 4, the reading unit 11 reads the QR code using a decoder (step S11). Then, the error correction location identification unit 12 uses the RS code to identify the error correction location of the read QR code (step S12).

Then, the weighting unit 13 weights the parts of the read QR code that are likely to be used for forgery (step S13). For example, the weighting unit 13 weights blocks in the QR code that have a probability of 1/2 or more of being used for forgery. As an example, the weighting unit 13 weights a portion corresponding to an error correction block.

Then, the forgery determination unit 14 counts the number of error correction bits included in the weighted block regarding the identified error correction location (step S14). The forgery determination unit 14 determines whether the count exceeds the threshold 21 (step S15). If it is determined that the count exceeds the threshold 21 (step S15; Yes), the forgery determination unit 14 determines that the read QR code is a forgery, and detects the forgery code (step S16). The determination process then ends.

On the other hand, if it is determined that the count does not exceed the threshold value 21 (step S15; No), the decoding unit 15 decodes the read QR code (step S17). The determination process then ends.

It has been explained that the weighting unit 13 weights the block included in the QR code, for example, if the probability of the block being used for forgery is 1/2 or more. However, the weighting unit 13 may perform weighting in stages according to the probability of being used for forgery. For example, the weighting unit 13 sets the weighting to "3" for a block that is 2/3 or more, and sets the weighting to "1" for a block that is 1/3 or more and less than 2/3, regarding the probability of being used for forgery. .5" may be used. Then, the forgery determination unit 14 counts the weighted sum of the error correction bits included in the weighted block with respect to the identified error correction location, and if the weighted sum exceeds the threshold 21, the counterfeit determination unit 14 probabilistically transitions. It is only necessary to determine that the QR code is

[Effects of Examples]
According to the above embodiment, the information processing device 1 weights each block included in the QR code to be processed depending on the probability that each block will be altered. The information processing device 1 determines whether the QR code is a QR code that changes stochastically according to the number of error bits included in the weighted block. According to this configuration, the information processing device 1 uses weighting according to the possibility of alteration when determining a QR code that transitions probabilistically, thereby erroneously determining a QR code that is not a forgery as a forgery. This can be avoided. That is, the information processing device 1 can accurately determine the QR code that changes probabilistically.

Further, according to the embodiment described above, if the block included in the QR code has a probability of being used for forgery at a predetermined rate or higher, the information processing device 1 weights the block. The information processing device 1 counts the number of error bits included in the weighted blocks. The information processing device 1 determines whether the QR code is a QR code that changes stochastically based on whether the counted number exceeds a specified value. According to this configuration, the information processing device 1 does not count the number of error bits of blocks whose probability of being used for forgery is lower than a predetermined percentage, thereby preventing parts that are unlikely to be used for forgery from becoming dirty or torn. false positives can be avoided.

Further, according to the above embodiment, the information processing device 1 weights each block included in the QR code in stages according to the probability that each block will be modified. The information processing device 1 counts the weighted sum of error bits included in the weighted blocks. The information processing device 1 determines whether the QR code is a QR code that changes stochastically based on whether the counted sum exceeds a specified value. According to this configuration, the information processing device 1 uses stepwise weighting according to the possibility of alteration in determining a QR code that changes probabilistically. It becomes possible to perform judgments with high accuracy. Furthermore, by not counting the number of error bits in blocks that are unlikely to be altered, the information processing device 1 can avoid false detections when parts that are unlikely to be used for forgery are soiled or torn. I can do it.

[others]
Note that each component of the illustrated information processing device 1 does not necessarily need to be physically configured as illustrated. In other words, the specific manner of distributing and integrating the information processing devices 1 is not limited to what is shown in the diagram, and all or part of the information processing devices 1 can be functionally or physically distributed in arbitrary units depending on various loads, usage conditions, etc. It can be configured in a distributed/integrated manner. For example, the reading unit 11 and the error correction location specifying unit 12 may be integrated as one unit. Further, the forgery determination unit 14 may be distributed into a counting unit that counts the number of error bits included in a weighted block and a determination unit that determines the counted number. Further, the storage unit 20 may be connected as an external device to the information processing device 1 via a network.

Further, the various processes described in the above embodiments can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. Therefore, an example of a computer that executes an information processing program including information processing that implements the same functions as the information processing apparatus 1 shown in FIG. 1 will be described below. FIG. 5 is a diagram illustrating an example of a computer that executes an information processing program.

As shown in FIG. 5, the computer 200 includes a CPU 203 that executes various calculation processes, an input device 215 that receives data input from a user, and a display control unit 207 that controls a display device 209. The computer 200 also includes a drive device 213 that reads programs and the like from a storage medium, and a communication control unit 217 that exchanges data with other computers via a network. Further, the computer 200 includes a memory 201 that temporarily stores various information, and an HDD 205. The memory 201, CPU 203, HDD 205, display control section 207, drive device 213, input device 215, and communication control section 217 are connected via a bus 219.

The drive device 213 is, for example, a device for the removable disk 211. The HDD 205 stores an information processing program 205a and information processing related information 205b.

The CPU 203 reads the information processing program 205a, develops it in the memory 201, and executes it as a process. This process corresponds to each functional unit of the information processing device 1. The information processing related information 205b corresponds to the threshold value 21 and the like. For example, the removable disk 211 stores information such as the information processing program 205a.

Note that the information processing program 205a does not necessarily have to be stored in the HDD 205 from the beginning. For example, the program is stored in a "portable physical medium" such as a flexible disk (FD), CD-ROM, DVD disk, magneto-optical disk, or IC card that is inserted into the computer 200. Then, the computer 200 may read out the information processing program 205a from these and execute it.

1 Information processing device 10 Control unit 11 Reading unit 12 Error correction location identification unit 13 Weighting unit 14 Forgery determination unit 15 Decoding unit 20 Storage unit 21 Threshold

Claims (5)

Each block included in the QR code to be processed is weighted according to the possibility that it will be modified,
An information processing program that causes a computer to execute a process of determining whether or not the QR code is a QR code that transitions probabilistically according to the number of error bits included in the weighted block. . In the weighting process, if a block included in the QR code has a probability of being used for forgery is a predetermined percentage or more, weighting the block;
The process for determining the
Counting the number of error bits included in the weighted block,
The information processing program according to claim 1, wherein it is determined whether the QR code is a QR code that changes stochastically depending on whether the counted number exceeds a specified value. The weighting process performs weighting in stages according to the possibility that each block included in the QR code will be modified,
The process for determining the
Calculating the weighted sum of error bits included in the weighted block;
The information processing program according to claim 1, wherein it is determined whether the QR code is a QR code that changes stochastically based on whether the calculated sum exceeds a specified value. a weighting unit that weights each block included in the QR code to be processed according to the possibility that each block will be modified;
a determination unit that determines whether the QR code is a QR code that transitions probabilistically according to the number of error bits included in the weighted block;
An information processing device comprising: Each block included in the QR code to be processed is weighted according to the possibility that it will be modified,
An information processing method characterized in that a computer executes a process of determining whether or not the QR code is a QR code that probabilistically transitions according to the number of error bits included in the weighted block. .

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