JP2017182358A - Information processing terminal, information processing method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information processing terminal, information processing method, and program that allow, even when an encrypted file has been decrypted by an application, the file to be appropriately used in the application.SOLUTION: An information processing terminal includes: first storage means in which information on encoding methods is stored; determination means that when an application uses a file at least part of which has been encrypted, determines an encoding method which has been applied to the file by referring to the first storage means; decoding means that decodes the at least part of the file which has been encrypted, by a decoding method corresponding to the encoding method determined by the determination means; decryption means that decrypts at least the part of the file which has been decoded by the decoding means; and encoding means that encodes at least the part of the file which has been decrypted by the decryption means, by the encoding method determined by the determination means, and transmits the encoded file to the application.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an information processing terminal, an information processing method, and a program.

  When an application processes a file, the application performs file open processing, interprets the contents of the file, and performs processing. When the file to be processed is encrypted, the software related to the decryption process decrypts the file before opening the file. In the file open process, the application performs an open process on the decrypted file, interprets the contents, and processes the file.

  In a specific application, file encoding and decoding are performed. For example, if the application is a mailer, base64 encoding is used. Since only text data can be placed in an e-mail, when binary data such as an image is attached to the e-mail, the image data is replaced (encoded) with text data in base64.

  In addition, the execution timing of the file open process in the application depends on the implementation and is not unified. For this reason, depending on the execution timing of the file open process, the above-described decryption process and decryption process may not be performed properly, and the software related to the decryption process may interpret the file as not being decrypted and may not decrypt the file. For example, when the application is a mailer, an encrypted attached file is encoded by base64 at the time of transmission on the transmission side. On the reception side, for example, in the preview browsing process, the received attachment file is hooked (replaced), and the software related to the decryption process performs the decryption process. However, since the received attached file is encoded in base64, the software related to the decryption process cannot interpret that the file is encrypted (is a decryption target) and does not decrypt it. After this, decryption processing is performed in the application, but the attached file remains encrypted, so the content of the attached file is displayed in a garbled state, or the attached file cannot be opened because it is damaged Situation occurs. A similar situation occurs with filers. That is, when each file archived (compressed) by ZIP or the like is an encrypted file, it is decrypted along with the file opening process. However, since the file is archived, the software related to the decryption process cannot interpret that the file is encrypted (is a decryption target) and does not decrypt it. As a result, a situation occurs in which the content of the file cannot be properly displayed by the filer.

  Here, for example, processing when previewing a file (encrypted file) encrypted in Microsoft Word (registered trademark) using Windows (registered trademark) mailer and Microsoft Outlook (registered trademark) will be described. . In this case, Microsoft Outlook decrypts the received encrypted file. When previewing the encrypted file, the decrypted encrypted file is stored as a temporary file. Then, Microsoft Word is activated and decryption processing of the encrypted file is performed.

  As described above, when encoding / decoding is performed on a file in an application, if the file used in the application is an encrypted file, the file is stored as a temporary file and decrypted. There are restrictions that must be performed separately and an application for performing decryption processing must be searched. As a result, the convenience and business efficiency of the application are reduced.

  Patent Documents 1 and 2 disclose related technologies for file encryption / decryption. Japanese Patent Application Laid-Open No. 2004-151867 describes data processing for acquiring a password candidate from input data (typically, e-mail data) when an attached file is encrypted, and attempting to cancel encryption using the candidate. An apparatus is disclosed.

  Patent Document 2 discloses an information processing apparatus having means for determining whether or not to decode by referring to a file header at the time of decoding. In Patent Document 2, “decoding” is used to mean decoding.

JP2015-125652A JP2008-134821

  Japanese Patent Application Laid-Open No. 2004-151858 does not describe the processing when an attached file is encoded by an application and is determined not to be decrypted.

  In Patent Document 2, since encoding is not taken into consideration, there is a problem in that when a file is encoded by an application, it is determined that the file is not a decoding target and is not decoded.

  The objective of this invention is providing the information processing terminal, the information processing method, and program which solve the above-mentioned subject.

  The information processing terminal according to the present invention includes a first storage unit that stores information related to an encoding method, and a storage unit when an application uses a file for at least a part of the encrypted file. Referring to and decrypting at least the encrypted part of the file by the discriminating means for discriminating the encoding scheme applied to the file and the decoding scheme corresponding to the encoding scheme discriminated by the discriminating means Decoding means for decoding, decoding means for decoding at least a portion of the file decoded by the decoding means, and encoding at least a portion decoded by the decoding means of the file by an encoding method determined by the determining means Encoding means for transmitting the encoded file to the application.

  The information processing terminal according to the present invention includes a first storage unit that stores information relating to an encoding method, and a first storage unit that uses a file for at least a part of an encrypted file. With reference to the storage means, at least the file is encrypted by a determination means for determining the encoding method applied to the file and a decoding method corresponding to the encoding method determined by the determination means A decoding means for decoding the part; a decoding means for decoding at least the portion of the file decoded by the decoding means; a second storage means; and a determination means for at least the portion of the file decoded by the decoding means A code for encoding the discriminated encoding method, storing the encoded file in the second storage means, and notifying the application of the storage location of the file And means, the.

  The information processing method of the present invention refers to the first storage means in which information about the encoding method is stored when an application uses a file for at least a partially encrypted file, A determination step for determining the encoding method applied to the file, and a decoding method for decoding at least an encrypted portion of the file by a decoding method corresponding to the encoding method determined in the determination step Encoding step, decoding at least a portion of the file decoded at the decoding step, and encoding at least the portion decoded at the decoding step of the file by the encoding method determined at the determination step Encoding the encoded file to the application.

  The information processing method of the present invention refers to the first storage means in which information about the encoding method is stored when an application uses a file for at least a partially encrypted file, A determination step for determining the encoding method applied to the file, and a decoding method for decoding at least an encrypted portion of the file by a decoding method corresponding to the encoding method determined in the determination step Encoding step, decoding at least a portion of the file decoded at the decoding step, and encoding at least the portion decoded at the decoding step of the file by the encoding method determined at the determination step The encoding step of storing the encoded file in the second storage means and notifying the application of the storage location of the file; No.

  The program of the present invention refers to the first storage means in which information relating to an encoding method is stored in a computer when an application uses a file for at least a part of the encrypted file. And at least an encrypted portion of the file is decrypted by a discrimination process for discriminating the encoding scheme applied to the file and a decoding scheme corresponding to the encoding scheme discriminated by the discrimination processing The decoding process, the decoding process for decoding at least the part decoded in the decoding step of the file, and the encoding method determined by the determination process for the part decoded at least in the decoding process of the file And encoding processing for transmitting the encoded file to the application.

  The program of the present invention refers to the first storage means in which information relating to an encoding method is stored in a computer when an application uses a file for at least a part of the encrypted file. And at least an encrypted portion of the file is decrypted by a discrimination process for discriminating the encoding scheme applied to the file and a decoding scheme corresponding to the encoding scheme discriminated by the discrimination processing The decoding process, the decoding process for decoding at least the part of the file decoded by the decoding process, and the encoding method determined by the determination process for at least the part of the file decoded by the decoding process The encoded file is stored in the second storage means, and an encoding process for notifying the storage location of the file to the application is executed.

  According to the present invention, even when an encrypted file is encoded by an application, the file can be appropriately used in the application.

It is a figure which shows the structure of the information processing terminal 1000 concerning 1st Embodiment. It is a figure explaining operation | movement of the information processing terminal 1000 concerning 1st Embodiment. It is a figure which shows the structure of the information processing terminal 1000a concerning 1st Embodiment. It is a figure which shows the structure of the information processing terminal 2000 concerning 2nd Embodiment. It is a figure explaining operation | movement of the information processing terminal 2000 concerning 2nd Embodiment. It is a figure which shows an example of the information which the encoding system database 206 concerning 2nd Embodiment stores. It is a figure which shows an example of the information which the file format database 207 concerning 2nd Embodiment stores. It is a figure which shows the hardware constitutions of the information processing terminal concerning 1st thru | or 6th Embodiment.

[First Embodiment]
FIG. 1 is a diagram illustrating a configuration of an information processing terminal 1000 according to the first embodiment.

  The information processing terminal 1000 includes a storage unit 101, a determination unit 102, a decoding unit 103, a decoding unit 104, and an encoding unit 105.

  The storage means 101 stores information related to the encoding method.

  The determination unit 102 refers to the storage unit 101 when an application (not shown) uses the file for at least a part of the encrypted file, and determines the encoding method applied to the file. Determine.

  The encoding unit 103 decodes at least the encrypted part of the file by a decoding method corresponding to the encoding method determined by the determining unit 102.

  Here, the application is an application such as a mailer or a filer, and is installed in the information processing terminal 1000. In the application, the processing target file is encoded so that the processing target file can be processed by the application.

  The decrypting means 104 decrypts at least a portion of the file decrypted by the decrypting means 103.

  The encoding unit 105 encodes at least a portion of the file decoded by the decoding unit 104 by the encoding method determined by the determination unit 102, and transmits the encoded file to the application.

  The operation of the information processing terminal 1000 will be described with reference to FIG. When the file open process is started in the application, the determination unit 102 refers to the storage unit 101 to determine the encoding method applied to the file (step S11). The decryption unit 103 decrypts at least the encrypted part of the file by a decryption method corresponding to the coding method determined by the determination unit 102 (step S12). The decryption means 104 decrypts at least the part of the file decrypted by the decryption means 103 (step S13). The encoding unit 105 encodes at least a portion of the file decoded by the decoding unit 104 by the encoding method determined by the determination unit 102, and transmits the encoded file to the application (step S14). The application decodes the encoded file and interprets the contents.

  According to the information processing terminal 1000 according to the first embodiment, with the above configuration and operation, even when an encrypted file is encoded by an application, the file is appropriately used in the application. can do.

  When the application uses a file, the determination unit 102 acquires the file from the application. For example, when the file open process is started in the application, the determination unit 102 can hook (replace) the Application Programming Interface (API) of the Operating System (OS) and start the process of step S11. . Alternatively, when the file opening process is started in the application, the application may transmit the file to the determination unit 102.

[Second Embodiment]
FIG. 3 is a diagram illustrating a configuration of the information processing terminal 1000a according to the second embodiment. The description of the same configuration as that of the information processing terminal 1000 according to the first embodiment is omitted.

  In the first embodiment, the encoding unit 105 transmits the encoded file to the application. In the present embodiment, the encoding unit 105a stores the encoded file in the storage unit 106a provided in the information processing terminal 1000a. The encoding means 105a has stored the file in the storage means 106a when the file is ready to be processed by the application (decoded and re-encoded) or stored in the storage means 106a. Notify the storage location to the application.

  Also in the information processing terminal 1000a according to the present embodiment, the same effects as those of the first embodiment can be obtained.

  The storage unit 101a and the storage unit 106a may be combined into one storage unit.

[Third Embodiment]
FIG. 4 is a diagram illustrating a configuration of the information processing terminal 2000 according to the third embodiment.

  The information processing terminal 2000 is an information terminal used by a user. In the information processing terminal 2000, the encryption software 200 and the application 300 are installed.

  The encryption software 200 includes an encryption / decryption unit 201, an encoding method determination unit 202, an encoding method registration unit 203, a file format determination unit 204, a file format registration unit 205, an encoding method database 206, and a file format database 207. Prepare.

  The encryption / decryption means 201 corresponds to the decryption means 104 in the first embodiment. The encryption / decryption means 201 has a function of executing file encryption / decryption processing, and performs mutual conversion between an unencrypted file (plain text file) and an encrypted file (encrypted file). . As a method for confirming whether a file is a decryption target in the file opening process, there is a method for confirming whether a file is a decryption target with reference to a file header, as described in Patent Document 3. .

  The encoding scheme determination unit 202 corresponds to the determination unit 102, the decoding unit 103, and the encoding unit 104 in the first embodiment. The encoding method determination unit 202 has a function of specifying an encoding method for an input file using an encoding method database 206 (described later). Also, the encoding scheme determination unit 202 performs encoding and decoding on the input file with reference to the specified encoding scheme and the decoding scheme corresponding to the encoding scheme.

  The encoding method registration unit 203 has a function of updating the encoding method database 206.

  The file format determination unit 204 has a function of specifying a file format with reference to a file format database 207 (described later).

  The file format registration unit 205 has a function of updating the file format database 207.

  Referring to FIG. 6, the encoding scheme database 206 stores information on various encoding schemes and decoding schemes. The encoding method database 206 corresponds to the storage unit 101 in the first embodiment. The encoding discriminating means 202 can interpret any encoding scheme registered in the encoding scheme database 206.

  Referring to FIG. 7, the file format database 207 stores information that is characteristic of the file, such as the file header size and extension, that is, information related to the file format.

  Referring to FIG. 4, the encoding method database 206 and the file format database 207 store in advance an encoding method, a decoding method, and a file format that are generally assumed to be used. In addition, the encoding method registration unit 203 and the file format registration unit 205 add the encoding method, the decoding method, and the file format to the encoding method database 206 and the file format database 207, respectively, as required by the user. It can also be stored.

  The application 300 includes a file processing function 301 and an encoding / decoding function 302.

  The file processing function 301 is used when processing a file such as a document file or an image file.

  The encoding / decoding function 302 is used when performing encoding processing or decoding processing on input information.

  The operation of the information processing terminal 2000 will be described with reference to FIG.

  The user starts using the application 300 on the information processing terminal 2000. When the file processing function 301 starts processing related to opening of the file, the encryption software 200 hooks (replaces) the OS API and starts processing.

  The file format determination unit 204 checks whether or not the target file has a file format registered in the file format database 207 (step S21). More specifically, the file format determination unit 204 refers to the file format database 207 for the file (target file) to be opened, and interprets the file extension, header, data portion, and the like. If the file format determination unit 204 determines in step S21 that the target file has a file format registered in the file format database 207 (yes in step S21), it is assumed that the target file is not encoded. The target file is passed to the application 300. In step S <b> 26, the application 300 that has received the target file uses the file processing function 301 to open the target file. By executing the process of step S21, it is possible to suppress occurrence of useless processing when opening an unencoded file.

  When the file format determination unit 204 determines in step S21 that the target file does not have the file format registered in the file format database 207 (no in step S21), the encoding format determination unit 202 in step S22. In this case, it is assumed that the target file has been subjected to some encoding, and decoding is attempted with a decoding method corresponding to the first encoding method stored in the encoding method database 206.

  In step S23, the encryption / decryption means 201 confirms whether or not the decrypted result is a decryption target. If it is determined that it is a decryption target (yes in step S23), the encryption / decryption means 201 performs decryption processing on the target file in step S24. Then, the encoding method determination unit 202 encodes the target file using the first encoding method (step S25) and passes it to the application 300. In step S26, the application 300 that has received the encoded target file uses the file processing function 301 to open the target file. The open process includes a decoding process by the encoding / decoding function 302. On the other hand, if it is determined that it is not a decoding target (no in step S23), in step S27, the encoding method discrimination means 202 encodes the target file using the first encoding method, and N (N is an arbitrary number) in step S28. (Integer). In step S29, it is determined whether or not decoding has been performed by all N decoding methods stored in the encoding method database 206, that is, whether or not N == max. If decoding has not been performed by all N decoding methods (no in step S29), the process returns to step S22, and the decoding methods stored in the encoding method database 206 are set to 2, 3,. Attempt to decrypt the target file using the th order. Even if all decoding schemes are attempted, if the decoding target is not applicable (Yes in step S29), the encoding scheme determination unit 202 passes the target file to the application 300. In step S <b> 26, the application 300 that has received the target file uses the file processing function 301 to open the target file. In this case, the target file remains encrypted. The information processing terminal 2000 can notify the user by, for example, displaying a notification of failure in decoding on a display unit (not shown) using a pop-up menu or a log.

  If the file decrypted by the Nth decryption method corresponds to the decryption target (yes in step S23), the encryption / decryption means 201 performs decryption processing of the target file in step S24. Then, the encoding scheme determination unit 202 encodes the target file using the Nth encoding scheme (step S25) and passes it to the application 300. In step S26, the application 300 that has received the encoded target file uses the file processing function 301 to open the target file. The open process includes a decoding process by the encoding / decoding function 302.

  According to the information processing terminal 2000 according to the present embodiment, even if the encrypted file is encoded by the application, the application 300 can appropriately interpret and use the file. For example, if the application is a mailer and an encrypted attachment that is encrypted and base64 encoded is received, the related technology hooks (replaces) the received attachment open process (preview browsing process). ) Perform decryption processing. However, since the encrypted attached file is encoded in base64, the software related to the decryption process cannot interpret that the file is encrypted (is a decryption target) and does not decrypt it. As a result, even if the attached file is decrypted, the content remains encrypted, so the content of the attached file is displayed in a garbled state, or the attached file cannot be opened because the file is damaged. It has occurred. According to the information processing terminal 2000 according to the present embodiment, for example, even when an encrypted attached file is encoded in base64, the encoding method is not improved without adding to the existing mailer. Interpret and display content appropriately. The same applies to applications other than mailers.

  If the encoding method can be specified in relation to the application, the decoding can be performed without performing the processing of FIG. In this case, the encoding method database 206 stores application information (for example, the hash value of the application 300) and the encoding method in association with each other. Then, the encoding method determination unit 202 searches for the encoding method stored in the encoding method database 206 using the information of the application 300 as a key.

  The encoding method discriminating unit 202 can store the information of the application 300, for example, the hash value of the application 300, in the encoding method database 206 when the decoding process is performed. That is, it is possible to add a step of storing the hash value of the application 300 in association with the encoding method after step S24 of FIG. As a result, if the application recognizes the encoding / decoding method once, encoding / decoding can be performed with the recognized method from the next time on, so that the use of the file after the next time is made more efficient. Can do.

  In addition, the encoding method registered in the encoding method database can be provided with means for assigning a priority based on the file header of the target file and various information. In this case, the encoding method determination unit 202 attempts to decode the target file using the decoding method corresponding to the encoding method with the higher priority in order.

  In this embodiment, in the description of the operation, when the user starts using the application 300 on the information processing terminal 2000, when the file processing function 301 starts processing related to opening of the file, the encryption software 200 is Explained that hooking OS API and starting processing. However, the present invention is not limited to this, and as described in the first embodiment, when the file open process is started in the application, the application 300 may transmit the file to the encryption software 200.

  In FIG. 5, when the file subjected to the decoding process is not a decoding target (no in step S23), the encoding method discrimination unit 202 encodes the file subjected to the decoding process (step S27) N Is incremented (step S28). Then, returning to step S22, the file encoded in step S27 is tried to be decoded by another method. Alternatively, if the file subjected to the decoding process is not a decoding target (no in step S23), the encoding method determining unit 202 sets N without encoding the file subjected to the decoding process. Increment (step S28) and return to step S22. In this case, when the encryption software 200 acquires a file from the application 300, a copy of the file is stored in the storage unit, and in step S22, the file stored in the storage unit (the file acquired from the application 300) is stored. Attempts to use another method for decoding Thereby, the encoding process of step S27 can be omitted.

[Fourth Embodiment]
In FIG. 5, after decrypting the target file, it is confirmed whether or not the target file is a decryption target (step S23 in FIG. 5). If the target file is a decryption target (yes in step S23) The decryption process is performed by the encryption / decryption means 201 of the encryption software 200 (step S24). If the encoding is performed M (M ≧ 2) times, the decoding process is not performed, N is incremented as a decoding failure (step S28), and the decoding process (step S22) is repeated. .

  In the present embodiment, it is confirmed whether or not the target file is to be decrypted after repeatedly performing the decryption process not by one time but by each of the N types of methods. In the case where M-fold encoding is applied to the encrypted file in the application by confirming whether or not it is a decryption target after performing M times of decryption in each of the N types of methods. Even if it exists, the file can be decrypted and used.

[Fifth Embodiment]
In 3rd and 4th embodiment, the aspect which decodes and decodes the whole object file was demonstrated. However, for example, when the application is a mailer and the encrypted attachment is stored in a file encoded with base64 or the like, only the encrypted file portion is decrypted and decrypted. You can also

  For example, even when encryption is performed in bit units or byte units, it is also possible to determine an encrypted portion and decrypt and decrypt only the encrypted portion.

[Sixth Embodiment]
In addition to the configuration of the information processing terminal in the first to fifth embodiments, the information processing terminal in the present embodiment includes a duplication unit that creates a duplication of the file when the application uses the file. In the information processing terminal according to the present embodiment, the processing described in FIG. 2 or 5 is performed on the file copied by the copying unit. As a result, the original encrypted and encoded file is not overwritten by the decrypted and encoded file, so that confidentiality can be maintained.

[Hardware configuration]
FIG. 8 is a diagram illustrating a hardware configuration of the information processing terminal according to the first to sixth embodiments. The information processing terminal according to the first to sixth embodiments includes a processor 100a, a memory 100b, a storage 100c, an input / output interface (input / output I / F) 100d, and a communication interface (communication I / F) 100e. The processor 100a, the memory 100b, the storage 100c, the input / output interface 100d, and the communication interface 100e are connected by a data transmission path 100f for transmitting / receiving data to / from each other.

  The processor 100a is an arithmetic processing device such as a Central Processing Unit or a Graphics Processing Unit. The processor 100a implements the functions of each processing unit by executing each program stored in the storage 100c described later. Here, when executing each program, the processor 100a may execute these programs after reading them onto a memory 100b described later, or may execute them without reading them onto the memory 100b.

  The memory 100b is a memory such as a random access memory (RAM) or a read only memory (ROM).

  The storage 100c is a storage device such as a hard disk drive, a solid state drive, or a memory card. The storage 100c may be a memory such as a RAM or a ROM. The storage 100c stores programs that realize the functions of the processing units.

  The communication interface 100e transmits / receives data to / from an external device or an external network. The communication interface 100e communicates with an external device or an external network via, for example, a wired network or a wireless network. Note that the hardware configuration of the information processing terminal is not limited to the configuration shown in FIG.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, It cannot be overemphasized that another modification and an application example are included unless it deviates from the meaning of this invention.

100a processor 100b memory 100c storage 100d input / output interface 100e communication interface 100f data transmission path 101, 101a, 106a storage means 102, 102a determination means 103, 103a decryption means 104, 104a decryption means 105, 105a encoding means 200 encryption software 201 Encoding / Decrypting Unit 202 Encoding Method Discriminating Unit 203 Encoding Method Registering Unit 204 File Format Discriminating Unit 205 File Format Registering Unit 206 Encoding Method Database 207 File Format Database 300 Application 301 File Processing Function 302 Encoding / Decoding Function 1000, 1000a, 2000 Information processing terminal

Claims (10)

First storage means for storing information relating to an encoding method;
A discriminating means for discriminating the encoding method applied to the file with reference to the first storage means when the application uses the file for a file at least partially encrypted;
Decoding means for decoding at least an encrypted part of the file in a decoding method corresponding to the encoding method determined by the determining means;
Decryption means for decrypting at least a portion of the file decrypted by the decryption means;
An encoding unit that encodes at least a portion of the file decoded by the decoding unit by the encoding method determined by the determining unit and transmits the encoded file to the application; Terminal. First storage means for storing information relating to an encoding method;
A discriminating means for discriminating the encoding method applied to the file with reference to the first storage means when the application uses the file for a file at least partially encrypted;
Decoding means for decoding at least an encrypted part of the file in a decoding method corresponding to the encoding method determined by the determining means;
Decryption means for decrypting at least a portion of the file decrypted by the decryption means;
A second storage means;
Encoding at least a portion of the file decoded by the decoding means by the encoding method determined by the determination means, storing the encoded file in the second storage means, and storing the file An information processing terminal comprising: encoding means for notifying the application of a position.   The information processing terminal according to claim 1, wherein the determination unit acquires the file from the application when the application uses the file.   When the file is encoded by a plurality of different encoding schemes, the decoding means refers to the first storage means and corresponds to the plurality of different encoding schemes. The information processing terminal according to claim 1, wherein decoding is performed a plurality of times by different decoding methods. When an application uses the file for at least a part of the encrypted file, the code applied to the file is referred to the first storage means storing information related to the encoding method. A determination step for determining the method of the conversion;
A decoding step for decoding at least an encrypted portion of the file in a decoding method corresponding to the encoding method determined in the determining step;
A decryption step of decrypting at least the decrypted portion of the file in the decryption step;
An encoding step of encoding at least a portion of the file decoded in the decoding step by the encoding method determined in the determination step, and transmitting the encoded file to the application. Information processing method. When an application uses the file for at least a part of the encrypted file, the code applied to the file is referred to the first storage means storing information related to the encoding method. A determination step for determining the method of the conversion;
A decoding step for decoding at least an encrypted portion of the file in a decoding method corresponding to the encoding method determined in the determining step;
A decryption step of decrypting at least the decrypted portion of the file in the decryption step;
Encoding at least a portion of the file decoded in the decoding step by the encoding method determined in the determining step, and storing the encoded file in a second storage means; And an encoding step of notifying the application of the storage location.   The information processing method according to claim 5 or 6, wherein, in the determination step, the file is acquired from the application when the application uses the file. On the computer,
When an application uses the file for at least a part of the encrypted file, the code applied to the file is referred to the first storage means storing information related to the encoding method. Discriminating process for discriminating the method of conversion,
A decryption process for decrypting at least an encrypted part of the file in a decryption system corresponding to the encoding system determined in the determination process;
A decryption process for decrypting at least the decrypted portion of the file in the decryption step;
An encoding process for encoding at least a portion of the file decoded by the decoding process by the encoding method determined by the determination process and transmitting the encoded file to the application; Let the program. On the computer,
When an application uses the file for at least a part of the encrypted file, the code applied to the file is referred to the first storage means storing information related to the encoding method. Discriminating process for discriminating the method of conversion,
A decryption process for decrypting at least an encrypted part of the file in a decryption system corresponding to the encoding system determined in the determination process;
A decryption process for decrypting at least a portion of the file decrypted by the decryption process;
Encoding at least a portion of the file decoded by the decoding process using the encoding method determined by the determination process, and storing the encoded file in a second storage unit, And a coding process for notifying the application of a storage location.   The program according to claim 8 or 9, wherein the determination process acquires the file from the application when the application uses the file.

Images