JP2015072379A - Terminal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of suppressing information stored in an external memory from being read for a dishonest purpose.SOLUTION: A terminal device 10 of the description comprises: an external memory interface to which an external memory 30 can be connected; an inner memory 20 for storing a cipher system, a first cipher key, and a rule; and a control part. When the external memory 30 is connected to the external memory interface and specific information 80 stored in the inner memory 20 is encrypted and is stored in the external memory, the cipher system and the first cipher key stored in the inner memory 20 are used for encryption by the control part, and about the specific information divided into a first part 86 and a second part 84 according to the rule stored in the inner memory 20, the first part 86 is stored in the external memory 30 and the second part 84 is stored in the inner memory 20 by the control part.

Description

  The technology disclosed in this specification relates to a terminal device capable of outputting information to an external memory.

  Patent Document 1 discloses a technique for preventing unauthorized use of an external storage medium connected to a terminal device. In the technique of Patent Document 1, when an external storage medium is connected to a terminal device and used, the user reads the RFID tag attached to the external storage medium to the terminal device and inputs the medium ID to the terminal device. At the same time, biometric authentication is performed and a user ID is input to the terminal device. The terminal device refers to the database of the management device connected to the terminal device, and stores the input user ID in the external storage medium when the input user ID is included in the ID list of users who can use the medium ID. Allow access to the information.

JP 2010-3001 A

  In the technique of Patent Document 1, if an external storage medium is lost or the external storage medium is stolen, information stored in the external storage medium may be read by a person other than the original user.

  The present specification provides a technique capable of suppressing unauthorized reading of information stored in an external memory.

  The terminal device disclosed in this specification includes an external memory interface that can connect an external memory, an internal memory that stores an encryption method, a first encryption key, and a division method, and a control unit. . When the external memory is connected to the external memory interface, the control unit encrypts the specific information stored in the internal memory or the external memory and stores it in the external memory. Specific information divided into the first part and the second part according to the division method stored in the internal memory and encrypted using the method and the first encryption key. The second portion is stored in the external memory, and the second portion is stored in the internal memory.

  In the above terminal device, the first part of the specific information that is encrypted and divided into the first part and the second part is stored in the external memory, and the second part is stored in the internal memory. Remember. For this reason, specific information cannot be completely reproduced only by the 1st part or only the 2nd part. Therefore, even if the external memory is lost or the external memory is stolen, it is possible to prevent the specific information from being read illegally by a person other than the user of the terminal device.

The block diagram which shows the structure of the terminal device 10 of 1st Example. The flowchart which shows the security processing of 1st Example. The figure which shows the specific example of a security process typically. The flowchart which shows the decompression | restoration process of 1st Example. The figure which shows the specific example of a restoration process typically. The figure which shows the specific example of an external output process typically.

  The main features of the embodiments described below are listed. In addition, the technical elements shown below are independent technical elements and exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. .

(Feature 1) The image processing apparatus may further include a reading unit that can read a specific information code that is encrypted with the second encryption key and has a specific area including the encryption related information and the division related information. The internal memory may further store a second encryption key. The control unit further acquires the encryption related information and the division related information from the read specific information code when the specific information code is read by the reading unit, and the acquired encryption related information and the division related information When the encryption method obtained from the information, the first encryption key, and the division method are stored in the internal memory, and the specific information stored in the internal memory or the external memory is encrypted and stored in the external memory, Specific information that is encrypted using the encryption method and the first encryption key stored in the internal memory and divided into the first part and the second part according to the division method indicated by the division-related information, The first part may be stored in the external memory, and the second part may be stored in the internal memory.

  According to this configuration, the terminal device reads the specific information code having the specific area encrypted by the second encryption key, thereby encrypting related information indicating the encryption method and the first encryption key; It is possible to acquire division-related information indicating a division method. Therefore, even if the external memory is lost or the external memory is stolen, as long as the specific information code is not read using the terminal device that stores the second encryption key, the first part and The encryption method, the first encryption key, and the division method used for generating the second part are not known. Therefore, it can suppress more effectively that specific information is read illegally by persons other than the user of a terminal device.

(Feature 2) The control unit further decodes the specific information from the first part stored in the external memory when the external memory in which the first part is stored is connected to the external memory interface. When the first part stored in the external memory and the second part stored in the internal memory are combined and stored in the internal memory according to the division method stored in the internal memory. The specific information may be generated by decryption using the encryption method and the first encryption key.

  According to this configuration, the terminal device can reproduce the specific information based on the first part and the second part.

(Feature 3) You may further provide the communication interface for communicating with another terminal device. The control unit may further output the second portion stored in the internal memory to another terminal device via the communication interface.

  According to this configuration, for example, the user of the terminal device can reproduce the specific information using the other terminal device by connecting the external memory storing the first portion to the other terminal device.

(First embodiment)
(Configuration of terminal device 10: FIG. 1)
A terminal device 10 shown in FIG. 1 is a portable terminal carried by a store clerk, for example. In another example, the terminal device 10 may be a stationary terminal device. A terminal device 10 illustrated in FIG. 1 includes an operation unit 12, a display unit 14, a control unit 16, a reading unit 18, an internal memory 20, a communication interface (I / F) 22, and an external memory I / F 24. Is provided.

  The operation unit 12 includes a plurality of keys. A user of the terminal device 10 can input various information to the terminal device 10 by operating the operation unit 12. The display unit 14 displays various information. The control unit 16 executes various processes according to programs in the internal memory 20. Details of processing executed by the control unit 16 will be described in detail later.

  The reading unit 18 can read various information codes such as a barcode and a two-dimensional code (for example, the information code 70 in FIG. 1).

  The information code 70 is a two-dimensional code. The information code 70 is printed, for example, on the surface of a card carried by a store clerk. The information code 70 has a public area 72 and a private area 74. The private area 74 is encrypted with an encryption key (hereinafter referred to as “second encryption key”). The internal memory 20 of the terminal device 10 stores the second encryption key.

  The information recorded in the open area 72 can be read by any terminal device as long as it is a terminal device (information code reader) that can read the information code. In the public area 72, identification information for simply identifying the information code is recorded.

  On the other hand, the information recorded in the private area 74 can be decrypted only by the terminal device (for example, the terminal device 10) in which the second encryption key is stored. That is, when the information code 70 is read by an arbitrary terminal device, the content of information that can be acquired by the terminal device differs depending on whether or not the terminal device stores the second encryption key. The private area 74 includes a first encryption key used for encrypting specific information (described later) and the type of encryption method used at that time (for example, DES, AES, FEAL, IDEA, etc.). And the rules for dividing the encrypted specific information into two parts, a first part and a second part, are recorded.

  The internal memory 20 stores various programs. The internal memory 20 stores a second encryption key for decrypting the private area 74. The internal memory 20 also stores various encryption methods (DES, AES, FEAL, IDEA, etc.). The internal memory 20 has an area where specific information can be stored. The specific information is, for example, master data (a product list, a barcode reading value, a product name, a sales price, etc.) related to a product sold at a store. Furthermore, the internal memory 20 also has an area capable of storing a first encryption key, encryption method information, and rules acquired by reading the information code 70.

  The communication I / F 22 is an interface for executing wireless communication with another terminal device 50 different from the terminal device 10. The terminal device 50 has the same configuration as the terminal device 10. In another example, the communication I / F 22 may be an interface for executing wired communication with the terminal device 50.

  The external memory I / F 24 is an interface for connecting the external memory 30 and the control unit 16. In the present embodiment, the external memory I / F 24 is a USB interface, and the external memory 30 is a USB memory. In another example, the external memory 30 may be an arbitrary external storage medium such as a memory card, CD, or DVD. In this case, the external memory I / F 24 may be an interface that can connect the external storage medium and the control unit 16.

(Processing executed by the control unit 16)
Next, each process (security process, restoration process, and external output process) executed by the control unit 16 of the terminal device 10 will be described with reference to FIGS.

(Security processing: Fig. 2 and Fig. 3)
The security process of FIG. 2 is a process of encrypting information in the internal memory 20 of the terminal device 10 and storing it in the external memory 30. Hereinafter, information stored in the external memory 30 from the internal memory 20 is referred to as “specific information”. FIG. 3 shows a specific example of security processing executed by the terminal device 10. In the following, the contents of the security processing of FIG. 2 will be described with reference to the specific example of FIG. As shown in FIG. 3, specific information 80 is stored in the internal memory 20 of the terminal device 10. First, the user of the terminal device 10 connects the external memory 30 to the external memory I / F 24 (see FIG. 3). Next, the user of the terminal device 10 operates the operation unit 12 to perform a predetermined security processing start operation. When a security processing start operation is performed, the control unit 16 starts the security processing of FIG.

  In S10 of FIG. 2, the control unit 16 monitors that the information code 70 is read. A user of the terminal device 10 can input an information code reading instruction by operating the operation unit 12 with the reading unit 18 facing the information code 70. When the information code reading instruction is input, the control unit 16 causes the reading unit 18 to read the information code 70. When the information code 70 is read by the reading unit 18, the control unit 16 determines YES in S10 of FIG. 2, and proceeds to S12.

  In S12, the control unit 16 determines whether or not the first encryption key, encryption method information, and rule are acquired from the read information code 70. In the example of FIG. 3, the internal memory 20 stores a second encryption key for decrypting the private area 74 of the read information code 70. Therefore, in S12, the control unit 16 decrypts the private area 74 of the read information code 70, records the first encryption key (for example, “ABCDEF”) recorded in the private area 74, and encryption method information. (For example, “DES”) and rules (for example, “Ratio = 0.5”) can be acquired. In this case, the control unit 16 determines YES in S12, and proceeds to S14. On the other hand, if the internal memory 20 does not store the second encryption key for decrypting the private area 74 of the read information code 70, the control unit 16 decrypts the private area 74. Can not be converted. Therefore, the first encryption key, encryption method information, and rule recorded in the non-public area 74 cannot be acquired. In this case, the control unit 16 determines NO in S12, and terminates the security process in FIG. 2 with an error.

  In S <b> 14, the control unit 16 stores the acquired first encryption key, encryption method information, and rule in the internal memory 20.

  Next, in S <b> 16, the control unit 16 selects a part (for example, 100 kB (kilobytes)) of the specific information 80 in the internal memory 20, and encrypts the selected information stored in the internal memory 20. Encryption is performed using the first encryption key in accordance with the encryption method indicated by the method information. In the example of FIG. 3, the encryption method indicated by the encryption method information (“DES”) stored in the internal memory 20 is “DES”, and the first encryption key is “ABCDEF”. Therefore, in S16, the control unit 16 encrypts a part of the specific information 80 (for 100 kB) using the first encryption key “ABCDEF” in accordance with the encryption method “DES”. Note that the first encryption key is an arbitrary character string. In another example, the first encryption key may be an arbitrary number string such as “123456”. As will be described later, the entire specific information 80 is encrypted by repeatedly executing the encryption processing of S16.

  Next, in S18, the control unit 16 divides a part of the specific information encrypted in S16 into a first part and a second part according to the rules stored in the internal memory 20. Subsequently, the control unit 16 stores one (first portion) of the divided information in the external memory 30 and stores the other (second portion) in the internal memory 20.

  In the example of FIG. 3, the rule is “Ratio = 0.5”. This rule “Ratio = 0.5” means that 0.5% of data is extracted (divided) from the original data at equal intervals from the top of the data. Therefore, in S18, the control unit 16 cuts out 0.5% (0.5 kB) of data from the top of a part of the encrypted specific information (100 kB) and cuts out 0.5 kB. Minute data (second portion) is stored in the internal memory 20, and the original 99.5 kB data (first portion) is stored in the external memory 30 via the external memory I / F 24.

  Next, in S <b> 20, the control unit 16 determines whether the processing has been completed for the entire specific information 80. When the processing of S16 and S18 is not completed for the entire specific information 80, the control unit 16 determines NO in S20 and returns to S16. In S16 after the return, the control unit 16 selects and encrypts an unprocessed part (for 100 kB) of the specific information 80. That is, the control unit 16 repeatedly executes the processes of S16 and S18 until the processes of S16 and S18 are completed for the entire specific information 80.

  When the processing of S16 and S18 is completed for the entire specific information 80, the control unit 16 determines YES in S20, and proceeds to S22. In S <b> 22, the control unit 16 deletes the original specific information 80 from the internal memory 20. Further, the control unit 16 deletes the first encryption key, encryption method information, and rule stored in S14 from the internal memory 20. When S22 ends, the control unit 16 ends the security process of FIG.

  As shown in FIG. 3, at the end of the security process, the external memory 30 has a first portion corresponding to the original data obtained by dividing the encrypted specific information 82 according to the rule “Ratio = 0.5”. 86 is stored. The internal memory 20 stores a second portion 84 corresponding to the data to be divided by dividing the encrypted specific information 82 according to the rule “Ratio = 0.5”.

(Restoration processing: FIGS. 4 and 5)
In the restoration process of FIG. 4, the first portion of the encrypted specific information is stored in the external memory 30, and the second portion of the encrypted specific information is stored in the internal memory 20 of the terminal device 10. In the case where the part is stored, the specific information is restored based on the first part and the second part. FIG. 5 shows a specific example of the restoration process executed by the terminal device 10. Hereinafter, the contents of the restoration process of FIG. 4 will be described with reference to the specific example of FIG. As shown in FIG. 5, the second portion 84 is stored in the internal memory 20 of the terminal device 10, and the first portion 86 is stored in the external memory 30. A user of the terminal device 10 first connects the external memory 30 to the external memory I / F 24 of the terminal device 10. Note that the first portion 86 and the second portion 84 in FIG. 5 are stored in the first portion 86 stored in the external memory 30 and the internal memory 20 as a result of the security processing performed in FIG. The same as the second portion 84 made. Next, the user of the terminal device 10 operates the operation unit 12 to perform a predetermined restoration process start operation. When the restoration process start operation is performed, the control unit 16 starts the restoration process of FIG.

  In S30 of FIG. 4, the control unit 16 monitors that the information code 70 is read. Since the content of the process of S30 is the same as that of S10 of FIG. 2, detailed description thereof is omitted. If YES in S30, the process proceeds to S32.

  In S32, the control unit 16 determines whether or not the first encryption key, the encryption method information, and the rule are acquired from the read information code 70. If YES in S32, the process proceeds to S34. On the other hand, if NO in S32, the restoration process of FIG. In S <b> 34, the control unit 16 stores the acquired first encryption key, encryption method information, and rule in the internal memory 20. Since the content of each process of S32 and S34 is the same as that of S12 and S14 of FIG. 2, detailed description is abbreviate | omitted.

  In S <b> 36, the control unit 16 performs the first part 86 stored in the external memory 30 and the first part stored in the internal memory 20 in accordance with the rule (for example, “Ratio = 0.5”) stored in the internal memory 20. Combined with the second portion 84. As a result, encrypted specific information 82 is generated. The control unit 16 stores the generated specific information 82 (that is, the encrypted specific information 82) in the internal memory 20.

  Next, in S38, the control unit 16 sets the encrypted specific information 82 generated in S36 according to the encryption method (for example, “DES”) indicated by the encryption method information stored in the internal memory 20. Decryption is performed using one encryption key (for example, “ABCDEF”). As a result, the specific information 80 is restored. The restored specific information 80 is stored in the internal memory 20.

  Next, in S40, the control unit 16 deletes the first encryption key, encryption method information, and rule stored in S34 from the internal memory 20. Although not shown in FIG. 5, in this embodiment, in S <b> 40, the control unit 16 performs the original first portion 86 in the external memory 30 and the original second portion in the internal memory 20. The portion 84 is not deleted. However, in another example, in S <b> 40, the control unit 16 may delete the original first portion 86 in the external memory 30 and the original second portion 84 in the internal memory 20. . When S40 ends, the control unit 16 ends the restoration process of FIG.

(External output processing; Fig. 6)
The external output process is a process of transmitting (outputting) the second portion to another terminal device 50 when the second portion is stored in the internal memory 20 of the terminal device 10. FIG. 6 shows a specific example of the external output process executed by the terminal device 10. As shown in FIG. 6, when the second portion 84 is stored in the internal memory 20, the user of the terminal device 10 operates the operation unit 12 to start a predetermined external output process. . Note that the first portion 86 and the second portion 84 in FIG. 6 are the first portion 86 and the internal memory 20 that are stored in the external memory 30 as a result of the security processing shown in FIG. Is the same as the second portion 84 stored in.

  When the start operation of the external output process is performed, the control unit 16 copies the second portion 84 stored in the internal memory 20. The control unit 16 transmits the copied second portion 84 to the other terminal device 50 via the communication I / F 22. When the other terminal device 50 receives the second portion 84 via the communication I / F (not shown), the other terminal device 50 stores the second portion 84 in the internal memory 60 of the terminal device 50. Thereby, the external output process by the control part 16 of the terminal device 10 is complete | finished.

  Through the external output process, the second portion 84 is stored in the internal memory 60 of the terminal device 50. Therefore, as shown in FIG. 6, the user of the terminal device 50 (may be the same user as the user of the terminal device 10) uses the external memory 30 in which the first portion 86 is stored in the terminal device 50. And a predetermined restoration process can be performed by an operation unit (not shown) of the terminal device 50. In that case, a control unit (not shown) of the terminal device 50 can perform the restoration process (see FIG. 4). As a result, the specific information 80 stored in the internal memory 20 of the terminal device 10 is stored in the internal memory 86 of the terminal device 50.

  The terminal device 10 according to the present embodiment has been described above. As shown in FIG. 3, the terminal device 10 according to the present embodiment encrypts the first part 86 out of the specific information divided into the first part 86 and the second part 84. The second portion 84 is stored in the internal memory 20. For this reason, the specific information 80 cannot be completely reproduced only by the first portion 86 or the second portion 84 alone. Therefore, even if the external memory 30 is lost or the external memory 30 is stolen, it is possible to prevent the specific information 80 from being read illegally by a person other than the user of the terminal device 10.

  As shown in S14 of FIG. 2 and FIG. 3, the terminal device 10 according to the present embodiment reads the information code 70 having the private area 74 encrypted by the second encryption key, thereby obtaining the first encryption key. And encryption method information and rules can be acquired. 2, the terminal apparatus 10 stores the first portion 86 in the external memory 30 and stores the second portion 84 in the internal memory 20, and then stores the first encryption key and the first encryption key. The encryption method information and the rule are deleted from the internal memory 20. Therefore, even if the external memory 30 is lost or the external memory 30 is stolen, as long as the information code 70 is not read using the terminal device that stores the second encryption key, the first part 86 and the encryption method used to generate the second portion 84 (eg, “DES”), the first encryption key (eg, “ABCDEF”), and the rules (eg, “Ratio = 0.5”). ) Is never known. Therefore, unauthorized reading of the specific information 80 by a person other than the user of the terminal device 10 can be more effectively suppressed.

  As shown in SS34 to S38 of FIG. 4 and FIG. 5, the terminal device 10 of the present embodiment is stored in the external memory 30 in accordance with a rule (for example, “Ratio = 0.5”) stored in the internal memory 20. The first part 86 and the second part 84 stored in the internal memory 20 are combined, and according to the encryption method (for example, “DES”) indicated by the encryption method information stored in the internal memory 20 Then, decryption is performed using the first encryption key (for example, “ABCDEF”) stored in the internal memory 20 to generate the specific information 80. That is, the terminal device 10 can reproduce the specific information 80 based on the first portion 86 and the second portion 84.

  As illustrated in FIG. 6, the terminal device 10 according to the present embodiment can transmit the second portion 84 stored in the internal memory 20 to another terminal device 50 via the communication I / F 22. Thereby, for example, the user of the terminal device 10 reproduces the specific information 80 using the other terminal device 50 by connecting the external memory 30 in which the first portion 86 is stored to the other terminal device 50. can do.

  The correspondence between the configuration of this embodiment and the description of the claims is described. A rule is an example of a “division method”. The information code 70 and the non-public area 74 are examples of “specific information code” and “specific area”. The first encryption key and encryption method information are examples of “encryption related information”. The rule is an example of “division related information”.

(Second embodiment)
Next, the second embodiment will be described focusing on differences from the first embodiment. The basic configuration of the terminal device 10 of this embodiment is the same as that of the first embodiment (see FIG. 1). However, in this embodiment, the processing order in the security processing and the restoration processing is different from that in the first embodiment. This embodiment is different from the first embodiment in that the specific information is divided prior to encryption in the security processing. Specifically, in the present embodiment, in the security process, the control unit 16 first stores the specific information before encryption into the first part and the second part according to the rules stored in the internal memory 20. Divide. Next, the control unit 16 uses the first encryption key stored in the internal memory 20 in accordance with the encryption method indicated by the encryption method information stored in the internal memory 20, and uses the first part and the second part. Are encrypted respectively. The control unit 16 stores the first part in the external memory 30 and stores the second part in the internal memory 20.

  Further, the present embodiment is different from the first embodiment in that in the restoration process, the first portion and the second portion are decoded before the combination of the first portion and the second portion. . Specifically, in the present embodiment, in the restoration process, the control unit 16 first performs the first encryption stored in the internal memory 20 according to the encryption method indicated by the encryption method information stored in the internal memory 20. Each of the first part and the second part is decrypted using the key. Next, the control unit 16 combines the decrypted first part and second part according to the rules stored in the internal memory 20 to generate specific information.

  The terminal device 10 of the present embodiment can also exhibit the same effects as the terminal device 10 of the first embodiment. That is, also in the present embodiment, the specific information cannot be completely reproduced by only one of the first part and the second part. Therefore, even if the external memory 30 is lost or the external memory 30 is stolen, it is possible to prevent the specific information from being read illegally by a person other than the user of the terminal device 10.

  As mentioned above, although the Example of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. For example, the following modifications may be included.

(Modification 1) In each of the above embodiments, as shown in FIG. 3, the control unit 16 performs security processing on the specific information 80 stored in the internal memory 20. However, the control unit 16 may perform security processing on the specific information stored in the external memory 30.

(Modification 2) In the first embodiment described above, the control unit 16 encrypts a part of the specific information 80 (for 100 kB) in the internal memory 20 in the security process, and a part of the encrypted specific information. (See S16 and S18 in FIG. 2). However, the present invention is not limited to this, and the control unit 16 encrypts the entire specific information in the internal memory 20 and divides the encrypted specific information into the first part and the second part in the security process. Also good.

(Modification 3) In each of the above embodiments, “Ratio = 0.5” is given as an example of the rule. However, the rule is not limited to this, and the specific information is encrypted, and the first part and the second part Any rule can be used as long as it can be divided into parts. Therefore, for example, the rule “Interval = 5, 20, 7; Max = 10k” may be used. The rule “Interval = 5, 20, 7; Max = 10k” is the first byte of the original data in the order of the 5th byte, the 20th byte, the 7th byte, the 5th byte, and so on. This means that the data is extracted (divided), and the division ends when the total of the divided data reaches 10 kB.

(Modification 4) In each of the above-described embodiments, as shown in S14 of FIG. 2 and S34 of FIG. The recorded first encryption key, encryption method information, and rule are acquired, and the acquired first encryption key, encryption method information, and rule are stored in the internal memory 20. However, the present invention is not limited thereto, and the first encryption key, encryption method information, and rules may be stored in advance in the internal memory 20. That is, if the internal memory 20 stores the encryption method information, the first encryption key, and the division method in advance, it is not always necessary to read the information code 70 having the private area 74.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

10: terminal device 12: operation unit 14: display unit 16: control unit 18: reading unit 20: internal memory 22: communication I / F
24: External memory I / F
30: External memory 50: Terminal device 60: Internal memory 70: Information code 72: Public area 74: Private area 80: Specific information 82: Encrypted specific information 84: Second part 86: First part

Claims (4)

A terminal device,
An external memory interface to which external memory can be connected;
An internal memory for storing the encryption method, the first encryption key, and the division method;
When the external memory is connected to the external memory interface, when the specific information stored in the internal memory or the external memory is encrypted and stored in the external memory, the encryption method stored in the internal memory and the first Specific information divided into the first part and the second part according to the division method stored in the internal memory and the first part stored in the external memory And a control unit for storing the second part in the internal memory,
Terminal device. A reading unit that can read a specific information code that is encrypted with the second encryption key and has a specific area including the encryption-related information and the division-related information;
The internal memory further stores a second encryption key,
The control unit
When the specific information code is read by the reading unit, the encryption-related information and the division-related information are acquired from the read specific information code, and the encryption obtained from the acquired encryption-related information and the division-related information Storing the encryption method, the first encryption key, and the division method in the internal memory,
When the specific information stored in the internal memory or the external memory is encrypted and stored in the external memory, it is encrypted using the encryption method and the first encryption key stored in the internal memory, and the internal information Specific information divided into the first part and the second part according to the division method stored in the memory, the first part is stored in the external memory, and the second part is stored in the internal memory, The terminal device according to claim 1. The control unit
When the external memory in which the first part is stored is connected to the external memory interface, when the specific information is decoded from the first part stored in the external memory, the specific information is stored in the internal memory. In accordance with the division method, the first part stored in the external memory and the second part stored in the internal memory are combined, and the encryption method and the first encryption key stored in the internal memory are combined. The terminal device according to claim 1, wherein specific information is generated by decoding using the terminal device. A communication interface for communicating with other terminal devices;
The control unit
The terminal device according to any one of claims 1 to 3, wherein the second part stored in the internal memory is output to another terminal device via a communication interface.

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