JP2017188902A - Information security method using key synchronization and information security system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information security method using key synchronization to be executed by a user terminal.SOLUTION: An information security method in which key synchronization executed by a user terminal is used, includes a step of receiving a processing request of secret information; a step of extracting a key for forming token corresponding to the secret information from a key pool of the user terminal; and a step of forming the token corresponding to the secret information by using the extraction key.EFFECT: Since the formation and decryption of the token is executed at a transmission and reception terminal without interpolating a token server, a risk in security can be diversified. Even when key information is exposed, the secret information is not exposed since the token is only transmitted/received at the transmission and reception terminal. Maintenance and inspection of equipment can be comparatively easily performed by replacing the key pool.SELECTED DRAWING: Figure 4

Description

  The present invention relates to information security technology, and more particularly, to a security method for information that requires confidentiality using key synchronization.

  Due to the development of electronic commerce, many commercial transactions are made not only offline but also online, and for this reason, confidential personal information such as credit cards is transmitted and used as needed on-line.

  In particular, unlike the existing procedures that require bank or card company authentication procedures at the time of payment, registering credit card information allows electronic payments that can be made without separate authentication procedures. The system is coming out. Typical examples are Google Wallet (registered trademark) and Apple Pay (registered trademark).

  On the other hand, as a side effect of such simplified electronic commerce, information security problems such as the leakage of personal information have emerged greatly, and various security measures have been researched and searched for.

  As part of such a process, PCI-DSS (Payment Card Industry Data Security) is a credit card industry security related standard for securely protecting credit card information and transaction information of cardholders handled by merchant payment agents. Standard).

  PCI-DSS specifies that protection measures must be taken when storing, calculating, and transmitting card information, but is recognized as a technology that satisfies the requirements stipulated in PCI-DSS. One of these is tokenization technology.

  Tokenization technology is a technology that uses existing credit card information or the like instead of digital tokens in offline and online commerce. The tokenization technique will be described in more detail with reference to FIG.

  FIG. 1 is a configuration diagram showing a configuration of an existing tokenization technique.

  Referring to FIG. 1, a merchant terminal, which is a transmission terminal 10 for sending credit card information, encrypts credit card information and transmits it to a token server to request generation of a token (a). In response to such a request, the token server 20 generates a token corresponding to the credit card information, matches the token with the credit card information, stores the token in the token storage 30, and transmits the generated token to the transmission end 10 ( b). The transmission end 10 receives such a token and sends it to the server of the card company which is the reception end 40 (c), and the reception end 40 receiving this requests the decryption to the token server 20 in order to confirm the credit card information. (D). The token server 20 decodes the credit card information based on the stored matching information and notifies the receiving end 40 (e).

  However, since such existing tokenization technology is a method of generating a digital token on the token server and restoring it to the original information again, separately for sensitive confidential information in the process of data exchange with the token server It is normal to perform encryption measures.

  In addition, since all confidential information and digital tokens are stored on the token server, security risks are concentrated on the token server, and high-level security such as authentication and authority management is required for connection to the token server. There is.

  An object of the present invention for solving the above-described problems is to provide an information security method using key synchronization executed at a user terminal.

  Another object of the present invention to solve the above problems is to provide an information security method using key synchronization executed by a service providing server.

  Still another object of the present invention to solve the above problems is to provide an information security method using key synchronization.

  An information security method using key sharing according to an aspect of the present invention for achieving the above object is performed by a user terminal and receives a request for processing confidential information, a key pool of the user terminal. ) To extract a key for generating a token corresponding to the confidential information and generating a token corresponding to the confidential information using the extracted key.

  Here, the key pool of the user terminal may store keys issued from a key server.

  Here, the key pool of the user terminal may be composed of keys derived by applying the unique value of the user terminal to the key issued to the service providing server linked with the user terminal.

  Here, the key pool of the user terminal is updated with the extracted key as the stage before or after the stage in which the user terminal generates the token corresponding to the confidential information using the extracted key. The method may further include the step of:

  Here, in the step of updating the key pool of the user terminal with the extracted key, the extracted key is excluded from the key pool of the user terminal or the presence or absence of extraction is displayed, and the selectively extracted key is displayed. The generated key can be stored in the user terminal key pool.

  Here, after the user terminal generates the token corresponding to the confidential information using the extracted key, the user terminal transmits the generated token and the key related information to the service providing server linked with the user terminal. Further can be included.

  An information security method using key synchronization according to another aspect of the present invention for achieving the above object is performed by a service providing server and receives a token and key related information from a user terminal. Extracting a key based on the key related information from the key pool of the service providing server using the key related information and restoring a token received using the extracted key to confidential information.

  Here, the key pool of the service providing server may store keys issued from a key server.

  Here, the key pool of the user terminal may be composed of keys derived by applying the unique value of the user terminal to the key issued to the service providing server.

  Here, the step of restoring the token received using the extracted key to the confidential information generates a key synchronized with the user terminal using the extracted key and the key related information, The token received using the synchronized key can be restored to confidential information.

  Here, the step of updating the key pool of the service providing server may be further included as a step before or after the step of restoring the token received using the extracted key to the confidential information.

  In order to achieve the above object, an information security method using key synchronization according to another aspect of the present invention includes a step in which a key server issues a key to a user terminal and a service providing server, and the user terminal stores confidential information. In response to a request for processing, a key for generating a token corresponding to confidential information is extracted from the key pool of the user terminal, and the user terminal generates a token corresponding to confidential information using the extracted key. A step of transmitting a token and key related information generated by a user terminal to a service providing server; a step of extracting a key from a key pool of the service providing server using the key related information transmitted by the service providing server; And the service provider server uses the key extracted from the service provider server key pool to From sending token comprising the step of restoring the confidential information.

  Here, the key pool of the user terminal may be composed of keys derived by applying the unique value of the user terminal to the key issued to the service providing server.

  Here, the user terminal uses the key extracted from the key pool of the user terminal as a step before or after the step of generating the token corresponding to the confidential information using the extracted key. The method may further include updating the key pool of the user terminal.

  Here, the step of updating the key pool of the user terminal is generated by using the extracted key by displaying whether the extracted key is excluded from the key pool of the user terminal or not. Keys can be stored in the key pool of the user terminal.

  Here, the stage in which the service providing server restores the confidential information from the token transmitted from the user terminal using the key extracted from the key pool of the service providing server includes the extracted key and the key related information. The key synchronized with the user terminal can be generated, and the received token can be restored using the synchronized key.

  Here, as a stage before or after the stage in which the service providing server restores the confidential information from the transmitted token using the key extracted from the key pool of the service providing server, the service providing server The method may further include updating the key pool.

  When the information security method using key synchronization according to the present invention as described above is used, tokens are generated and decrypted at the transmitting and receiving ends without using a token server. it can.

  In addition, even if the key is exposed at the key server, the token is exchanged only at the sending and receiving ends, so there is no exposure of confidential information, and the equipment can be repaired and inspected relatively easily by replacing the key pool. There is.

  Also, due to key synchronization, it is not necessary to transfer the key itself except at the time when the key is issued. For this reason, even if key-related information is leaked during the transmission process from the user terminal to the service providing server, the key cannot be understood without the key pool, so it is easier to deal with security problems during the transmission process. can do.

The block diagram which showed the structure of the existing tokenization technique. The block diagram which shows the information security method using the key synchronization based on the Example of this invention. The block diagram for demonstrating the transmission end and receiving end apparatus which perform the information security method using the key synchronization based on the Example of this invention. 6 is a flowchart illustrating an information security method using key synchronization executed by a user terminal according to an embodiment of the present invention. 6 is a flowchart illustrating an information security method using key synchronization executed by a service providing server according to an embodiment of the present invention. The sequence diagram which shows the information security method using the key synchronization based on the Example of this invention.

  While the invention is susceptible to various modifications and alternative embodiments, specific embodiments have been shown by way of example in the drawings and will be described in detail in the detailed description. However, this should not be construed as limiting the invention to the specific embodiments, but should be understood to include all modifications, equivalents or alternatives that fall within the spirit and scope of the invention. In describing the drawings, similar reference numerals are given to similar components for description.

  Terms such as “first”, “second”, “A”, and “B” may be used to describe various components, but the components are not limited by the terms. The terms are only used to distinguish one component from another. For example, without departing from the scope of the present invention, the first component can be named as the second component, and similarly the second component can be named as the first component. The terms and / or include any item of a combination of a plurality of related listed items or a plurality of related listed items.

  When a component is referred to as being “coupled” or “connected” to another component, it may be directly coupled to or connected to another component. It should be understood that there may be other components in between. On the other hand, when a component is referred to as being “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

  The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular form includes the plural form unless the context clearly dictates otherwise. In this application, terms such as “comprising” or “having” are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof, as described in the specification. It should be understood that it does not exclude in advance the presence or additionality of one or more other features or numbers, steps, actions, components, components or combinations thereof.

  Unless defined otherwise, all terms used herein include technical or scientific terms and have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Have. Terms such as those defined in commonly used dictionaries should be construed as having a meaning consistent with the meaning possessed in the context of the related art and are ideal or excessive unless explicitly defined in this application. Is not interpreted as a formal meaning.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 2 is a configuration diagram showing a configuration for an information security method using key synchronization.

  Referring to FIG. 2, the present invention may include a transmitting end 100, a key server 200, and a receiving end 300.

  First, the user terminal as the transmitting end 100 plays a role of generating a token from confidential information using the key issued from the key server 200 and transmitting the token and the key related information to the receiving end 300. Here, the user terminal may mean a smart phone, a tablet PC, a laptop computer, a computer, a smart home appliance, a POS terminal, or a device that provides an IoT service in which the card payment app is driven, but is not limited thereto. Various communication apparatuses that are required to handle confidential information may be applicable.

  The key server 200 is a server device capable of short-distance or long-distance communication using a wired / wireless network. The key server 200 generates and stores a key, and issues the generated key to the transmitting end 100 and the receiving end 300. can do.

  The service providing server that is the receiving end 300 may be various server devices connected to a wired / wireless network such as a credit card company server or an online server that provides an IoT service, but is not limited thereto. The token and key-related information is received from 100, and based on this, the token can be interpreted to confirm the confidential information.

  For example, the transmitting end 100 may be a card settlement machine held by a card member store, and the receiving end 300 may be a card company server that performs card settlement.

  Specifically, the business owner of the card member store can use the sending end 100 to make a payment based on the customer's payment request. In such a process, it is necessary to collect the customer payment information including the card number and notify the card company server.

  When a payment request is received to execute this, the sending end 100 generates a token by using one of the keys issued in advance (a) from the key server 200 and the customer's payment information to create a key pool. Update (b). Thereafter, the token is transmitted to the receiving end 300 together with the key related information used for generating the token (c). After receiving the key-related information and the token, the receiving end 300 extracts the key from the key pool using the key-related information. Using the key thus extracted, the token can be restored again to the customer's payment information and the key pool can be updated (d), and the card company can perform a payment operation using the restored payment information. .

  FIG. 3 is a block diagram illustrating a transmitting end and a receiving end apparatus that execute an information security method using key synchronization according to an embodiment of the present invention.

  The roles of the transmitting end 100 and the receiving end 300 will be described in more detail with reference to FIG.

  The transmitting end 100 may include a key pool 110, a key extracting unit 120, and a token generating unit 130.

  The key pool 110 may be a kind of storage configured with one or more keys transmitted from the key server 200. In addition, when a key is extracted, the key pool 110 can update information on a key that stores such a new key reflecting such extracted information. A specific update process will be described in detail later.

  The key extraction unit 120 can extract a key used when generating a token from the key pool 110. The key extracted in this way is used for generating a token by the token generation unit.

  The token generation unit 130 can generate a token corresponding to the confidential information using the key extracted by the key extraction unit. Here, the token is an alternative means of confidential information, and even if it is leaked to the outside, the confidential information is unknown, so it becomes meaningless information.

  As described above, each piece of information related to the key extracted by the key extraction unit 120, that is, the key related information and the token generated by the token generation unit 130 are transmitted to the receiving end 300.

  The receiving end 300 may include a key pool 310, a key extraction unit 320, and an information restoration unit 330.

  The key pool 310 is a kind of storage composed of keys transmitted from the key server 200, and can share a common key with the key pool 110 at the transmission end 100, but has different keys. You can also. The key information can be updated in the same manner as at the transmitting end 100.

  The key extraction unit 320 serves to extract a key from the key pool 310 using the key related information transmitted by the transmission end 100, and similarly executes a function equivalent to the key extraction unit 120 at the transmission end 100. .

  The information restoring unit 330 can restore the confidential information using the token received at the transmitting end 100 and the key extracted by the key extracting unit.

  FIG. 4 is a flowchart relating to an information security method using key synchronization performed at a user terminal.

  Referring to FIG. 4, first, the user terminal receives a confidential information processing request (S110).

  In addition, confidential information may mean personal information that requires confidentiality such as a user's credit card number, account number, financial information, medical records, criminal records, credential records, stock transactions and lending records, It is not limited to this. Here, the confidential information processing request may be requested by an application driven by the user terminal by the user's electronic commerce, or may be requested by a card terminal in the offline sales floor, but is not limited thereto. is not.

  Here, the user terminal can have a unique value that can be distinguished from other user terminals, but the unique value is distinguished from the identification symbol (ID) of the user terminal and other user terminals. May mean a symbol having. It can also hold a key pool ID and a transmission counter. The ID of the key pool is a unique identification symbol of the key pool that the user terminal has in distinction from other user terminals, and the transmission counter may mean a number or symbol used for key synchronization.

  A key for token generation corresponding to confidential information is extracted from the key pool of the user terminal (S120). Here, the key issued from the key server can be stored in the key pool. At this time, the meaning that the key is issued from the key server does not necessarily mean that the key is directly received from the key server, but may have a key issued by the key server when the user terminal is manufactured. The key may be stored in the key pool of the user terminal through a separate issuing process after manufacturing.

  In addition, the key server can give a certain expiration date to the key issued to improve security, so that the already issued key cannot be used after the expiration date, and a new key is issued. You can also

  Here, the key pool of the user terminal may be composed of keys derived by applying the unique value of the user terminal to the key issued to the service providing server. Here, as a method for deriving the key, various encryption algorithms can be used. Specifically, for example, a TDEA (Triple data encryption algorithm) encryption algorithm can be applied.

  With this configuration, even if the service providing server and the user terminal have different key pools, the service providing server uses the key extracted from its own key pool to issue the user terminal from the key server. It is possible to derive the key received. That is, the key used in the service providing server can be synchronized with the key of the user terminal.

  Therefore, it is possible to reduce the difficulty that the user terminal and the service providing server synchronize the key pool with each other, and to reduce the problem that the user providing server has to maintain and manage a separate key pool for each user terminal. be able to. Also, unlike the service providing server, the user terminal can extract the key from its own key pool and use it as it is without separately calculating it, so the load on the user terminal is not great.

  However, such a configuration is not necessarily required, and does not mean that the key server provides the same key to the user terminal and the service providing server.

  In addition, the process in which the key server issues the key and transmits the key to the user terminal and the service providing server may be performed by adopting a secure channel or data encryption in order to prevent the risk of key leakage.

  Here, extracting a key necessary for token generation from the key pool may be performed in accordance with a preset order, or a previously stored key may be extracted. It is also possible to extract the key corresponding to the transmission counter using the transmission counter of the user terminal. At this time, the transmission counter is a number that increases by one each time a key is used to generate a token, and serves to distinguish the currently used key from the key stored in the key pool. When the token is transmitted to the server, it is transmitted together and used as a means for synchronizing the key with the service providing server.

  However, this is only an example, and various other means that can synchronize the key with the service providing server can be used.

  A token corresponding to the confidential information is generated using the extracted key (S130). Here, for example, a random number generator (RNG) using a key or an encryption method may be applied to generate a token. However, in this case as well, it is needless to say that confidential information is not known from the token, and different confidential information must be generated with different tokens, and it is preferable that two or more confidential information does not exist in the same token.

  In addition, for compatibility with existing systems, it is advantageous to generate a token having the attribute of confidential information, that is, the same attribute as the length and type of data. In order to maintain the same attribute, specifically, for example, an attribute maintaining encryption method (FRE; Format Preserving Encryption) can be applied.

  The key pool can be updated with the extracted key before or after the user terminal generates a token corresponding to the confidential information using the extracted key (S130).

  Here, the method of updating the key pool can exclude the extracted key from the key pool or display the presence / absence of extraction, and the key generated using the selectively extracted key can be displayed in the key pool. Can be saved. Here, a variety of methods can be used to generate a key using the extracted key. For example, one-way encryption or a hash function can be used, and transmission previously held by the user terminal. You can use the counter together. At this time, the generated key is a key used at the time of the next transmission, and is stored in the key pool, and the transmission counters can be stored so as to correspond to each other.

  More specifically, an example can be described by generating a key by one-way encrypting the extracted key as many times as the number of transmission counters. In such a configuration, the transmission counter is set by the service providing server. By using it, the key used by the user terminal can be derived.

  In addition, when keys are generated, the number of keys in the key pool of the user terminal after key extraction may be equal to or less than a preset number, or may be generated every time an update is performed.

  As described above, when the user terminal is configured to directly generate and use the key, it is possible to reduce the difficulty of receiving the key from the key server and synchronizing with the service providing server.

  However, it is not always necessary to follow such a method, and it is also possible to update in such a manner that the key stored in the key pool of the service providing server is issued from the key server.

  Further, the token and key related information generated after generating the token (S130) can be transmitted to the service providing server (S140). Here, the key-related information can include information on a position and a method by which the key used for extraction and token generation from the key pool can be confirmed or derived. For example, a unique value held by the user terminal or a service providing server Can include a synchronization symbol for deriving a synchronization key.

  FIG. 5 is a flowchart regarding an information security method using key synchronization executed by the service providing server.

  Referring to FIG. 5, first, the service providing server receives the token and key related information from the user terminal (S210). Here, the key-related information can include information on a position and a method by which the key used for extraction and token generation from the key pool can be confirmed or derived. For example, a unique value held by the user terminal or a service providing server Can include a synchronization symbol for deriving a synchronization key.

  A key is extracted from the key pool of the service providing server using the received key related information (S220). Here, the key issued from the key server can be stored in the key pool of the service providing server.

  Here, a secure channel and data encryption can be employed when the key of the key server is issued.

  At this time, in the key pool setting of the service providing server, a sufficient number of keys should be included so that two or more confidential information is not tokenized or detokenizaion with one key. Is advantageous.

  Here, the method for extracting the key can extract a key corresponding to the key pool of the user terminal using the key related information. Specifically, it is possible to obtain the unique value of the user terminal from the key related information and extract the corresponding key. The meaning of corresponding may mean a case where the user terminal can derive a key issued from the key server by applying a unique value of the user terminal to the extracted key.

  The received token is restored to the confidential information using the extracted key (S230). Specifically, a key synchronized with the user terminal is generated using the extracted key and key-related information, and the received token is confidentially generated using the synchronized key. Information can be restored.

  For example, first, a unique value of the user terminal (for example, an identification symbol of the user terminal) is obtained from the key related information, and this value is applied to the extracted key for conversion. Through such conversion, the user terminal can obtain the key issued from the key server. Here, various encryption algorithms can be used as the conversion method, and specifically, for example, a TDEA encryption algorithm can be applied.

  However, if the user terminal used the key issued from the key server as it is, it can be restored as it is, but if you generated and used the key yourself, you do not know the key used for tokenization . Therefore, it is possible to obtain information used by the user terminal for key generation through the key related information, and use this to derive the key used by the user terminal for tokenization. More specifically, after extracting a synchronization symbol such as a transmission counter from the key-related information, the key used by the user terminal is obtained using the same method as that used by the user terminal. Can be derived.

  In addition, the key pool may be updated before or after the step of restoring the token received using the extracted key to the confidential information (S230) (S240).

  Here, if the expiration date of the extracted key has expired or the transmission counter in the received key-related information has exceeded a certain number of times when it is updated, there is a security risk at the user terminal or service providing server. There may be a case where is detected.

  In such a case, the updating method may request the key server to issue a key, issue a key to the service providing server, and issue a new key again to the user terminal.

  FIG. 6 is a sequence diagram relating to an information security method using key synchronization executed by interaction between a key server, a user terminal, and a service providing server.

  With reference to FIG. 6, the overall interaction of the key server, the user terminal, and the service providing server will be described.

  First, the key server issues a key to the user terminal and the service providing server (S300-1, S300-2). As a result, the user terminal and the service providing server have a key pool composed of issued keys (S310-1, S310-2).

  Here, the key pool of the user terminal may be composed of keys derived by applying the unique value of the user terminal to the key issued to the service providing server.

  When a request for processing confidential information occurs at the user terminal, the user terminal extracts a key for generating a token corresponding to the confidential information from the key pool of the user terminal (S320).

  The user terminal generates a token corresponding to the confidential information using the extracted key (S330).

  Further, before or after the token generation (S330), the user terminal can update the key pool of the user terminal with the key extracted from the key pool of the user terminal (S340). Here, the extracted key is excluded from the key pool of the user terminal or the presence or absence of the extraction is displayed, and the key generated using the selectively extracted key is stored in the key pool of the user terminal be able to.

  The token and key related information generated by the user terminal is transmitted to the service providing server (S350).

  The service providing server extracts a key from the key pool set in the service providing server using the key related information transmitted (S360).

  Using the key extracted from the key pool set in the service providing server, the service providing server restores the confidential information from the token transmitted from the user terminal (S370). More specifically, a key synchronized with the user terminal is generated using the extracted key and key related information, and the received token is restored using the synchronized key. Can do.

  As a step before or after restoring the confidential information (S370), the key pool of the service providing server can be updated (S380).

  According to the above-described embodiment of the present invention, the service providing server can restore the confidential information from the transmitted token by using the key extracted from the key pool set in the service providing server. Since the token is generated and decrypted at the transmission / reception end without going through the token server, the security risk can be distributed.

  In addition, even if the key is exposed at the key server, the token is exchanged only at the sending and receiving ends, so there is no exposure of confidential information, and the equipment can be repaired and inspected relatively easily by replacing the key pool. There is.

  Further, due to key synchronization, transmission of the key itself is not required except for the time when the key is issued. For this reason, even if the key-related information is leaked in the transmission process from the user terminal to the service providing server, the key is not known, so that it is possible to more easily cope with the security problem in the transmission process.

  The configuration of the user terminal of the transmitting end 100, the key server 200, and the service providing server of the receiving end 300 according to the embodiment of the present invention has been described in each constituent unit for convenience of explanation. At least two of them can be combined into one component, or one component can be divided into a plurality of components to perform the function. Examples are included in the scope of the present invention without departing from the essence of the present invention.

  In addition, the operations of the user terminal of the transmitting terminal 100, the key server 200, and the service providing server of the receiving terminal 300 according to the embodiment of the present invention are embodied as a computer-readable program or code on a computer-readable recording medium. Is possible. Computer readable recording media include all types of recording devices that can store data that can be read by a computer system. In addition, a computer-readable recording medium is distributed in a computer system connected to a network, and a computer-readable program or code can be stored and executed in a distributed manner.

  Although the foregoing has been described with reference to preferred embodiments of the invention, those skilled in the art will recognize that the invention is within the scope and spirit of the invention as defined by the following claims. It will be understood that various modifications and changes can be made.

10: user terminal 20: token server 30: token storage 40: service providing server 100: transmission end 110: key pool 120: key extraction unit 130: token generation unit 200: key server 300: reception end 310: key pool 320 : Key extraction unit 330: Information restoration unit

Claims (17)

In the information security method using key synchronization executed by the user terminal,
Receiving a request to process confidential information;
Extracting a key for generating a token corresponding to the confidential information from a key pool of the user terminal;
Generating a token corresponding to the confidential information using the extracted key. An information security method using key synchronization.   The information security method using key synchronization according to claim 1, wherein a key issued from a key server is stored in the key pool of the user terminal.   The key pool of the user terminal includes a key derived by applying a unique value of the user terminal to a key issued to a service providing server that is linked to the user terminal. Item 3. An information security method using key synchronization according to item 2. As a step before or after the user terminal generates a token corresponding to the confidential information using the extracted key,
The method of claim 1, further comprising: updating a key pool of the user terminal with the extracted key. Updating the user terminal key pool with the extracted key comprises:
The extracted key is excluded from the key pool of the user terminal or the presence or absence of extraction is displayed, and the key generated using the extracted key is selectively stored in the key pool of the user terminal The information security method using key synchronization according to claim 4, wherein: After the user terminal generates a token corresponding to the confidential information using the extracted key,
The method of claim 1, further comprising transmitting the generated token and key-related information to a service providing server linked with the user terminal. In the information security method using key synchronization executed by the service providing server,
Receiving token and key related information from the user terminal;
Extracting the key based on the key related information from the key pool of the service providing server using the received key related information;
Using the extracted key to restore the received token to sensitive information. An information security method using key synchronization.   8. The information security method using key synchronization according to claim 7, wherein a key issued from the key server is stored in the key pool of the service providing server.   The key according to claim 8, wherein the key pool of the user terminal is composed of keys derived by applying a unique value of the user terminal to a key issued to the service providing server. Information security method using synchronization. Using the extracted key to restore the received token to confidential information includes:
Using the extracted key and the key-related information, generate a key synchronized with the user terminal, and restore the received token to confidential information using the synchronized key. The information security method using key synchronization according to claim 7, wherein: As a step before or after restoring the received token to confidential information using the extracted key,
The information security method using key synchronization according to claim 7, further comprising updating a key pool of the service providing server. In the information security method using key synchronization,
The key server issues a key to the user terminal and the service providing server;
The user terminal receiving a request for processing confidential information and extracting a key for generating a token corresponding to the confidential information from a key pool of the user terminal;
Generating a token corresponding to the confidential information using the extracted key by the user terminal;
Transmitting the token and key-related information generated by the user terminal to the service providing server;
Extracting the key from the key pool of the service providing server using the key related information transmitted by the service providing server;
The service providing server using a key extracted from the key pool of the service providing server to restore confidential information from the token transmitted from the user terminal, information using key synchronization Security method.   The key according to claim 12, wherein the key pool of the user terminal is composed of keys derived by applying a unique value of the user terminal to a key issued to the service providing server. Information security method using synchronization. As a step before or after the step of generating a token corresponding to the confidential information using the extracted key by the user terminal,
The key synchronization according to claim 12, further comprising updating the key pool of the user terminal with the key extracted from the key pool of the user terminal. Information security method. The step of updating the key pool of the user terminal includes:
The extracted key is excluded from the key pool of the user terminal or the presence or absence of extraction is displayed, and the key generated using the extracted key is selectively stored in the key pool of the user terminal The information security method using key synchronization according to claim 14, wherein: The service providing server uses the key extracted from the key pool of the service providing server to restore the confidential information from the token transmitted from the user terminal,
Generating a key synchronized with the user terminal using the extracted key and the key-related information, and restoring the received token using the synchronized key; An information security method using key synchronization according to claim 12. As a step before or after the service providing server restores the confidential information from the transmitted token using the key extracted from the key pool of the service providing server,
The method of claim 12, further comprising the step of the service providing server updating a key pool of the service providing server.