Information processing apparatus, information processing method, and program

Abstract

To improve security even when data encrypted and uploaded in a first place is downloaded and decrypted in a second place.SOLUTION: There is provided an information processing apparatus including: a memory; a generation unit for generating a first random number key, outputting the first random number key, and recording the first random number key in the memory; an erasing unit, with the first random number key recorded in the memory, for encrypting a second random number key used to encrypt first data to be uploaded, to generate second data, recording the second data in the memory, and erasing the second random number key and the first random number key recorded in the memory; and a decryption unit for decrypting the second random number key for decrypting the first data to be downloaded based on the acquired first random number key and the second data recorded in the memory.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an information processing apparatus, an information processing method, and a program.

Background Art

[0002] Patent Document 1 discloses a technique in which a relay device relays communication between terminal devices when the terminal devices of a plurality of terminal devices communicate with each other, and the relay device and the terminal device communicate data encrypted with a one-time pad.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique described in Patent Document 1, for example, the case where a user downloads and decrypts data encrypted at a first location and uploaded at a second location has not been considered. In this case, for example, when the user moves from the first location to the second location while holding the encryption key and the encryption key is stolen, a security problem occurs.

[0005] An object of the present disclosure is to provide a technique capable of improving security even in the case of downloading and decrypting data encrypted at a first location and uploaded at a second location in view of the above-described problems.

Means for Solving the Problems

[0006] In a first aspect according to the present disclosure, there is provided an information processing apparatus including a memory, a generation unit that generates a first random number key, outputs the first random number key, and records the first random number key in the memory, an encryption unit that encrypts a second random number key used for encrypting first data to be uploaded with the first random number key recorded in the memory to generate second data, records the second data in the memory, and deletes the second random number key and the first random number key recorded in the memory, and a decryption unit that decrypts the second random number key for decrypting the first data to be downloaded based on the acquired first random number key and the second data recorded in the memory.

[0007] Further, in a second aspect according to the present disclosure, an information processing apparatus having a memory performs a process of generating a first random number key, outputting the first random number key, and recording the first random number key in the memory, a process of encrypting a second random number key used for encrypting first data to be uploaded with the first random number key recorded in the memory to generate second data, recording the second data in the memory, and deleting the second random number key and the first random number key recorded in the memory, and a process of decrypting the second random number key for decrypting the first data to be downloaded based on the acquired first random number key and the second data recorded in the memory. There is provided an information processing method for executing the above.

[0008] Further, in a third aspect according to the present disclosure, a computer having a memory is caused to perform a process of generating a first random number key, outputting the first random number key, and recording the first random number key in the memory, a process of encrypting a second random number key used for encrypting first data to be uploaded with the first random number key recorded in the memory to generate second data, recording the second data in the memory, and deleting the second random number key and the first random number key recorded in the memory, and a process of decrypting the second random number key for decrypting the first data to be downloaded based on the acquired first random number key and the second data recorded in the memory. There is provided a program for causing the above to be executed.

Advantages of the Invention

[0009] According to one aspect, security can be improved even when data encrypted and uploaded at a first location is downloaded and decrypted at a second location.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0011] The principles of the present disclosure are described with reference to several exemplary embodiments. These embodiments are described for illustrative purposes only and are not intended to limit the scope of the present disclosure, but rather to assist those skilled in the art in understanding and implementing the present disclosure. The disclosure described herein may be implemented in various ways other than those described below.

[0012] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each drawing is merely an example for explaining one or more embodiments. Each drawing is not associated with only one specific embodiment, but may be associated with one or more other embodiments. As can be understood by those skilled in the art, various features or steps described with reference to any one of the drawings can be combined with the features or steps shown in one or more other drawings, for example, to create embodiments that are not explicitly illustrated or described. Not all of the features or steps shown in any one of the drawings for explaining exemplary embodiments are necessarily essential, and some features or steps may be omitted. The order of the steps described in any of the drawings may be changed as appropriate.

[0014] (Embodiment 1) <Configuration> Referring to FIG. 1, the configuration of the information processing apparatus 10 according to the embodiment will be described. FIG. 1 is a diagram showing an example of the configuration of the information processing apparatus 10 according to the embodiment. The information processing apparatus 10 includes a storage unit (memory) 11, a generation unit 12, an erasure unit 13, and a decoding unit 14. These units may be realized by the cooperation of one or more programs installed in the information processing apparatus 10 and hardware such as the processor 101 and the memory 102 of the information processing apparatus 10.

[0015] The storage unit 11 records various data. The generation unit 12 generates a first random number key. Further, the generation unit 12 outputs the first random number key to an external device or the like. Also, the generation unit 12 causes the storage unit 11 to record the first random number key.

[0016] The erasure unit 13 encrypts the second random number key used for encrypting the first data to be uploaded with the first random number key recorded in the storage unit 11 to generate second data. Then, the erasure unit 13 causes the storage unit 11 to record the second data, and erases the second random number key and the first random number key recorded in the storage unit 11.

[0017] The decoding unit 14 decodes a second random number key for decoding the first data to be downloaded based on the first random number key acquired from an external device or the like and the second data recorded in the storage unit 11.

[0018] (Embodiment 2) Next, with reference to FIG. 2, the configuration of the information processing system 1 according to the embodiment will be described. <System Configuration> FIG. 2 is a diagram showing a configuration example of the information processing system 1 according to the embodiment. In the example of FIG. 2, the information processing system 1 includes an information processing apparatus 10 and a server 20. In the example of FIG. 2, the information processing apparatus 10 and the server 20 are connected so as to be communicable via a network N. Note that the number of the information processing apparatus 10 and the server 20 is not limited to the example of FIG. 2.

[0019] Examples of the network N include, for example, the Internet, a mobile communication system, a wireless LAN (Local Area Network), a LAN, and a bus. Examples of the mobile communication system include, for example, the fifth-generation mobile communication system (5G), the sixth-generation mobile communication system (6G, Beyond 5G), the fourth-generation mobile communication system (4G), and the third-generation mobile communication system (3G).

[0020] The information processing apparatus 10 is, for example, a terminal such as a smartphone, a tablet, or a notebook personal computer that a user possesses.

[0021] The server 20 is, for example, a device such as a server, a cloud server, or a personal computer. The server 20 stores data uploaded from terminals such as the information processing apparatus 10 and causes the terminals to download the stored data.

[0022] <Hardware Configuration> FIG. 3 is a diagram showing a hardware configuration example of the information processing apparatus 10 according to the embodiment. In the example of FIG. 3, the information processing apparatus 10 (computer 100) includes a processor 101, a memory 102, and a communication interface 103. These components may be connected by a bus or the like. The memory 102 stores at least a part of the program 104. The communication interface 103 includes an interface necessary for communication with other network elements.

[0023] When the program 104 is executed by the cooperation of the processor 101, the memory 102, etc., at least a part of the processing of the embodiment of the present disclosure is performed by the computer 100. The memory 102 may be of any type suitable for a local technology network. The memory 102 may be, as a non-limiting example, a non-transitory computer-readable storage medium. Also, the memory 102 may be implemented using any suitable data storage technology such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. Although only one memory 102 is shown for the computer 100, there may be several physically different memory modules in the computer 100. The processor 101 may be of any type. The processor 101 may include one or more of a general-purpose computer, a dedicated computer, a microprocessor, a digital signal processor (DSP), and, as a non-limiting example, a processor based on a multi-core processor architecture. The computer 100 may have a plurality of processors such as an application-specific integrated circuit chip that is temporally dependent on a clock that synchronizes the main processor.

[0024] Embodiments of the present disclosure may be implemented in hardware or dedicated circuitry, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that can be executed by a controller, a microprocessor or other computing device.

[0025] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in program modules, which are executed on a device on a target physical processor or virtual processor to execute the processes or methods of the present disclosure. Program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The functions of the program modules may be combined or divided among the program modules as desired in various embodiments. The machine-executable instructions of the program modules can be executed within local or distributed devices. In a distributed device, the program modules can be arranged on both local and remote storage media.

[0026] The program code for executing the methods of the present disclosure may be written in any combination of one or more programming languages. This program code is provided to a processor or controller of a general-purpose computer, a dedicated computer, or other programmable data processing device. When the program code is executed by the processor or controller, the functions / operations in the flowchart and / or the implemented block diagram are executed. The program code is executed entirely on the machine, partly on the machine as a stand-alone software package, partly on the machine, partly on a remote machine, or entirely on a remote machine or server.

[0027] The program can be stored using various types of non-transitory computer-readable media and supplied to a computer. Non-transitory computer-readable media include various types of tangible recording media. Examples of non-transitory computer-readable media include magnetic recording media, magneto-optical recording media, optical disk media, semiconductor memories, etc. Magnetic recording media include, for example, flexible disks, magnetic tapes, hard disk drives, etc. Magneto-optical recording media include, for example, magneto-optical disks, etc. Optical disk media include, for example, Blu-ray disks, CD (Compact Disc)-ROM (Read Only Memory), CD-R (Recordable), CD-RW (ReWritable), etc. Semiconductor memories include, for example, solid state drives, mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, RAMs (random access memories), etc. Also, the program may be supplied to the computer by various types of transitory computer-readable media. Examples of transitory computer-readable media include electrical signals, optical signals, and electromagnetic waves. The transitory computer-readable media can supply the program to the computer via wired communication paths such as electric wires and optical fibers, or wireless communication paths.

[0028] <Processing> Next, referring to FIG. 4, an example of the processing of the information processing apparatus 10 according to the embodiment will be described. FIG. 4 is a flowchart showing an example of the processing of the information processing apparatus 10 according to the embodiment.

[0029] Note that the processing of the following steps S101 and S102 may be executed, for example, at a location (the first location) where data downloaded from the server 20 is decoded, such as the user's home or workplace. In step S101, the generation unit 12 generates a first random number key. Here, the generation unit 12 may generate, for example, a random number of a specific data size (for example, 1 gigabyte) as the first random number key.

[0030] Subsequently, the generation unit 12 outputs the first random number key to an external device or the like for recording, and also records the first random number key in the storage unit 11 (step S102). Note that the process of outputting the first random number key to an external device or the like and the process of recording the first random number key in the storage unit 11 may be executed in either order.

[0031] Here, the generation unit 12 may output and record the first random number key to a removable recording medium (external device) such as a USB (Universal Serial Bus) memory and an SD memory card. Note that the recording medium may be stored in a secure place locked or the like at a first location such as at home.

[0032] In addition, the generation unit 12 also records the first random number key in the storage unit 11 of the information processing apparatus 10. Note that the storage unit 11 may be an SSD (Solid State Drive) or the like built into the information processing apparatus 10. The storage unit 11 may include a plurality of storage devices.

[0033] Note that the processes of step S103 and step S104 below may be executed, for example, at a location (second location) where data is uploaded to the server 20, such as the user's business trip destination or customer site. Note that the user may encrypt the confidential data with the second random number key and upload it to the server 20 using, for example, an information processing apparatus 10 or a terminal (for example, a personal computer) different from the information processing apparatus 10 existing at the second location.

[0034] Subsequently, the erasure unit 13 generates second data obtained by encrypting a second random number key used for encrypting the first data to be uploaded with the first random number key recorded in the storage unit 11 (step S103). Here, the erasure unit 13 may encrypt the second random number key with the first random number key by, for example, a one-time pad. Note that the one-time pad may be an encryption method that uses a random number sequence only once at most. In this case, the erasure unit 13 may generate second data obtained by encrypting the second random number key, for example, by using the exclusive logical sum (XOR, Exclusive OR) of the second random number key and a random number sequence having the same length (data size) as the second random number key among the first random number keys.

[0035] Also, the erasure unit 13 may determine, for example, whether the data size of the first random number key is equal to or greater than the data size of the second random number key. When the data size of the first random number key is equal to or greater than the data size of the second random number key, the erasure unit 13 may encrypt the second random number key with the first random number key by a one-time pad.

[0036] On the other hand, when the data size of the first random number key is not equal to or greater than the data size of the second random number key, the erasure unit 13 may encrypt the second random number key by an encryption method other than the one-time pad with the first random number key. In this case, the erasure unit 13 may encrypt, for example, at least a part of the random number sequence included in the first random number key by using it a plurality of times. In this case, the erasure unit 13 may generate second data obtained by encrypting the second random number key, for example, by using the exclusive logical sum of the second random number key and a random number sequence having the same length as the second random number key generated based on the first random number key. The erasure unit 13 may encrypt the second random number key with the first random number key by using, for example, AES (Advanced Encryption Standard) or the like.

[0037] Subsequently, the erasure unit 13 causes the storage unit 11 to record the second data, and erases the second random number key and the unencrypted first random number key recorded in the storage unit 11 (step S104). Thereby, for example, even if the information processing apparatus 10 is stolen or the like while the user is returning from the second location to the first location, the combination of the first random number key that can restore the second random number key and the second data, and the second random number key itself can be prevented from being passed to malicious persons. Therefore, for example, even if the security such as the password of the information processing apparatus 10 and the password for logging in to the server 20 is breached, it is possible to reduce the decryption of the confidential data.

[0038] Note that the process of causing the storage unit 11 to record the second data, the process of erasing the second random number key, and the process of erasing the first random number key recorded in the storage unit 11 may be executed in any order.

[0039] Note that the following process of step S105 may be executed, for example, at the user's home, workplace, or other location (the first location) where the data downloaded from the server 20 is decrypted. Subsequently, the decryption unit 14 decrypts the second random number key for decrypting the first data to be downloaded based on the first random number key acquired from an external device or the like and the second data recorded in the storage unit 11 (step S105). Thereby, the user can decrypt the encryption of the confidential data downloaded from the server 20 using the second random number key.

[0040] The decryption unit 14 may determine whether information indicating the position when decrypting the second random number key in step S105 satisfies a predetermined condition based on information indicating the position when the first random number key is generated by the generation unit 12 in step S101. And when the said predetermined condition is satisfied, the decryption part 14 may decrypt a 2nd random number key. On the other hand, when the said predetermined condition is not satisfied, the decryption part 14 may reject the decryption of a 2nd random number key and alert | report the error which shows the meaning to a user. Thereby, for example, it is possible to reduce the decryption of the second random number key at a location other than the first location such as the user's home.

[0041] In this case, the generation unit 12 may acquire information indicating the position (first position) of the information processing apparatus 10 when generating the first random number key, and cause the storage unit 11 to record the information indicating the position. Then, when decrypting the second random number key, the decryption unit 14 may acquire information indicating the position (second position) of the information processing apparatus 10 and determine whether or not the predetermined condition is satisfied.

[0042] In the present disclosure, the information indicating the position of the information processing apparatus 10 may be measured using a satellite positioning system such as GPS (Global Positioning System), for example. Also, in the present disclosure, the information indicating the position of the information processing apparatus 10 may be acquired from a base station (access point) of a wireless LAN (Local Area Network), for example. Further, the information indicating the position of the information processing apparatus 10 may be acquired from a base station of a mobile phone carrier (for example, gNB (next generation Node B)), for example.

[0043] In the present disclosure, the information indicating the position of the information processing apparatus 10 may be information indicating latitude and longitude, for example. In this case, the predetermined condition may include, for example, that the distance between the first position and the second position is equal to or less than a threshold value.

[0044] Also, in the present disclosure, the information indicating the position of the information processing apparatus 10 may be identification information corresponding to the base station to which the information processing apparatus 10 is connected (present in the area) (for example, the SSID (Service Set Identifier) of a wireless LAN or the cell ID of a mobile communication system), for example. In this case, the predetermined condition may include, for example, that the identification information corresponding to the base station connected at the first position and the identification information corresponding to the base station connected at the second position are the same.

[0045] (Example of encrypting the first random number key and storing it in the information processing apparatus 10) In the above example, in step S102, the first random number key was recorded in an external device stored at home or the like, and in step S105, an example of obtaining the first random number key from the external device was described. Instead of this, or in addition to this, the generation unit 12 or the deletion unit 13 may encrypt the first random number key and record it in the storage unit 11, and the decryption unit 14 may be able to decrypt and obtain the encryption of the first random number key only at the first location. Thereby, for example, the external device becomes unnecessary. In this case, when the information indicating the position when decrypting the second random number key satisfies a predetermined condition based on the information indicating the position when the first random number key was generated by the generation unit 12, the decryption unit 14 may decrypt the first random number key from the third data in which the first random number key is encrypted.

[0046] In this case, the generation unit 12 may obtain the information indicating the first position described above and record it in the storage unit 11. Then, the decryption unit 14 may obtain the information indicating the second position described above and determine whether the predetermined condition described above is satisfied. The process of encrypting the first random number key and recording it in the storage unit 11 may be executed by the generation unit 12 in step S102, or may be executed by the deletion unit 13 in step S104.

[0047] <Modification Example> The information processing apparatus 10 may be a device included in one housing, but the information processing apparatus 10 of the present disclosure is not limited to this. Each part of the information processing apparatus 10 may be realized by, for example, cloud computing configured by one or more computers. Such information processing apparatuses 10 are also included in an example of the "information processing apparatus" of the present disclosure.

[0048] As described above, the present disclosure has been described with reference to the embodiments, but the present disclosure is not limited to the above-described embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. And each embodiment can be combined with other embodiments as appropriate.

[0049] Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the spirit thereof.

[0050] Some or all of the above embodiments can be described as follows in the appended claims, but are not limited thereto. Note that some or all of the elements (for example, configurations and functions) described in each dependent claim subordinate to Appendix 1 can be subordinate to independent claims in other categories in the same subordinate relationship. Some or all of the elements described in any appended claim can be applied to various hardware, software, recording means for recording software, systems, and methods. (Appendix 1) A memory, A generation unit that generates a first random number key, outputs the first random number key, and records the first random number key in the memory, An erasure unit that encrypts a second random number key used for encrypting the first data to be uploaded with the first random number key recorded in the memory to generate second data, records the second data in the memory, and erases the second random number key and the first random number key recorded in the memory, A decryption unit that decrypts the second random number key for decrypting the first data to be downloaded based on the acquired first random number key and the second data recorded in the memory, An information processing apparatus having the above. (Appendix 2) The generation unit generates the first random number key, outputs the first random number key to an external device, and records the first random number key in a memory, The decryption unit decrypts the second random number key based on the first random number key acquired from the external device and the second data, The information processing apparatus according to Appendix 1. (Appendix 3) The external device is located at a first location where the first random number key is generated, The first location is different from a second location where the second data is generated, The information processing apparatus according to Appendix 2. (Appendix 4) The information processing apparatus is Generate the first random number key at a first location, generate the second data at a second location, and decrypt the second random number key at the first location. The information processing apparatus according to appended note 1 or 2. (Appended note 5) The erasure unit encrypts the second random number key by one-time pad using the first random number key. The information processing apparatus according to appended note 1 or 2. (Appended note 6) The erasure unit When the data size of the first random number key is equal to or greater than the data size of the second random number key, encrypt the second random number key by one-time pad using the first random number key. When the data size of the first random number key is not equal to or greater than the data size of the second random number key, encrypt the second random number key by an encryption method other than one-time pad using the first random number key. The information processing apparatus according to appended note 1 or 2. (Appended note 7) When information indicating a position when decrypting the second random number key satisfies a predetermined condition based on information indicating a position when the first random number key was generated by the generation unit, the decryption unit decrypts the second random number key. The information processing apparatus according to appended note 1 or 2. (Appended note 8) When information indicating a position when decrypting the second random number key satisfies a predetermined condition based on information indicating a position when the first random number key was generated by the generation unit, the decryption unit decrypts the first random number key from third data in which the first random number key was encrypted. The information processing apparatus according to appended note 1 or 2. (Appended note 9) An information processing apparatus having a memory A process of generating a first random number key, outputting the first random number key, and causing the first random number key to be recorded in the memory, Encrypt the second random number key used for encrypting the first data to be uploaded with the first random number key recorded in the memory to generate second data, record the second data in the memory, and erase the second random number key and the first random number key recorded in the memory, A process of decrypting the second random number key for decrypting the first data to be downloaded based on the acquired first random number key and the second data recorded in the memory, An information processing method for executing. (Appendix 10) In a computer having a memory, Generate a first random number key, output the first random number key, and record the first random number key in the memory, Encrypt the second random number key used for encrypting the first data to be uploaded with the first random number key recorded in the memory to generate second data, record the second data in the memory, and erase the second random number key and the first random number key recorded in the memory, A process of decrypting the second random number key for decrypting the first data to be downloaded based on the acquired first random number key and the second data recorded in the memory, A program for executing. (Appendix 11) Having an information processing device and a server, The information processing device includes: A memory, A generation unit that generates a first random number key, outputs the first random number key, and records the first random number key in the memory, An erasure unit that encrypts the second random number key used for encrypting the first data uploaded to the server with the first random number key recorded in the memory to generate second data, records the second data in the memory, and erases the second random number key and the first random number key recorded in the memory, A decryption unit that decrypts the second random number key for decrypting the first data downloaded from the server based on the acquired first random number key and the second data recorded in the memory, Information processing system.

Explanation of symbols

[0051] 1 Information processing system 10 Information processing device 11 Storage unit (memory) 12 Generation unit 13 Erasure unit 14 Decryption unit 20 Server

Claims

1. A memory, a generation unit that generates a first random key, outputs the first random key, and records the first random key in the memory, an erasure unit that encrypts a second random key used for encrypting first data to be uploaded with the first random key recorded in the memory to generate second data, records the second data in the memory, and erases the second random key and the first random key recorded in the memory, a decryption unit that decrypts the second random key for decrypting the first data to be downloaded based on the acquired first random key and the second data recorded in the memory, An information processing apparatus having the above.

2. The generation unit generates the first random key, outputs the first random key to an external device, records the first random key in the memory, The decryption unit decrypts the second random key based on the first random key acquired from the external device and the second data, The information processing apparatus according to Claim 1.

3. The external device is located at a first location where the first random key is generated, The first location is different from a second location where the second data is generated, The information processing apparatus according to Claim 2.

4. The information processing apparatus generates the first random key at a first location, generates the second data at a second location, and decrypts the second random key at the first location, The information processing apparatus according to Claim 1 or 2.

5. The erasure unit encrypts the second random key with the first random key using a one-time pad, The information processing apparatus according to Claim 1 or 2.

6. The erasure unit when the data size of the first random key is equal to or greater than the data size of the second random key, encrypts the second random key with the first random key using a one-time pad, when the data size of the first random key is not equal to or greater than the data size of the second random key, encrypts the second random key with an encryption method other than a one-time pad using the first random key, The information processing apparatus according to Claim 1 or 2.

7. The decryption unit decrypts the second random key when information indicating the position when decrypting the second random key satisfies a predetermined condition based on information indicating the position when the first random key was generated by the generation unit, The information processing apparatus according to Claim 1 or 2.

8. When information indicating a position at which the second random number key is decrypted satisfies a predetermined condition based on information indicating a position at which the first random number key was generated by the generation unit, the decryption unit decrypts the first random number key from third data in which the first random number key is encrypted. The information processing apparatus according to claim 1 or 2.

9. An information processing apparatus having a memory, a process of generating a first random number key, outputting the first random number key, and recording the first random number key in the memory; a process of encrypting a second random number key used for encrypting first data to be uploaded with the first random number key recorded in the memory to generate second data, recording the second data in the memory, and deleting the second random number key and the first random number key recorded in the memory; a process of decrypting a second random number key for decrypting the first data to be downloaded based on the acquired first random number key and the second data recorded in the memory; An information processing method for executing the above.

10. In a computer having a memory, a process of generating a first random number key, outputting the first random number key, and recording the first random number key in the memory; a process of encrypting a second random number key used for encrypting first data to be uploaded with the first random number key recorded in the memory to generate second data, recording the second data in the memory, and deleting the second random number key and the first random number key recorded in the memory; a process of decrypting a second random number key for decrypting the first data to be downloaded based on the acquired first random number key and the second data recorded in the memory; A program for causing the above to be executed.

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