KR101792498B1 - Method for data security using key synchronization and data securuty system using the same - Google Patents

Abstract

An information security method using key synchronization performed by a user terminal is disclosed. The information security method using key synchronization performed by a user terminal according to an exemplary embodiment of the present invention includes receiving a request for processing confidential information, generating a token corresponding to confidential information in a key pool of the user terminal, Extracting the key, and generating a token corresponding to the confidential information using the extracted key. Therefore, since the token is generated and decrypted at the transmitting and receiving end without the token server, the risk of security can be dispersed. Also, even if the key information is exposed, since the token is transmitted only at the transmitting and receiving end, confidential information is not exposed, and the equipment can be relatively easily repaired and replaced by replacing the key pool.

Description

TECHNICAL FIELD The present invention relates to an information security method and an information security system using key synchronization,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information security technology, and more particularly, to a security method of information requiring confidentiality using key synchronization.

Due to the development of e-commerce, many commercial transactions are being made not only offline but also online, and confidential information of individuals including credit cards is transmitted and used online at any time.

Especially in recent years, unlike the existing procedures requiring the authentication process of a bank or a credit card company at the time of settlement, an electronic payment system that can be settled without a separate authentication procedure appears when credit card information is registered. Google Wallet and Apple Pay.

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

As part of that process, there is the PCI-DSS (Payment Card Industry Data Security Standard) as a security-related standard for the credit card industry to safeguard the credit card information and transaction information of the card members treated by the merchant payment service provider.

PCI-DSS specifies that protection measures must be taken in storing, computing and transmitting the card information. One of the perceived technologies that satisfy the requirements specified in PCI-DSS is tokenization technology.

Tokenization technology refers to a technology that replaces existing credit card information with digital tokens in offline and online commerce. The tokenization technique will be described in more detail with reference to FIG.

1 is a block diagram showing a configuration of an existing tokenizing technique.

Referring to FIG. 1, a store terminal 10, which is a transmission terminal 10 for transmitting credit card information, encrypts credit card information, transmits the encrypted credit card information to a token server, and requests token creation (1). The token server 20 receives the request, 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 terminal 10 (②). The transmitting terminal 10 receives the token and sends it to the card company server as the receiving terminal 40. The receiving terminal 40 requests the token server 20 to decrypt the token server 20 in order to confirm the credit card information ). The token server 20 decrypts the credit card information based on the stored matching information and notifies the receiving terminal 40 of the credit card information (5).

However, this conventional tokenization technique is a method of generating a digital token in the token server and restoring the original token information. Therefore, in the process of exchanging data with the token server, it is common that a separate encryption step is carried out for sensitive confidential information .

Also, since the confidential information and the digital token are stored in the token server and the risk of security is concentrated in the token server, there is a problem that a high level of security such as authentication and authority management is required for connection to the token server.

In order to solve the above problems, an object of the present invention is to provide an information security method using key synchronization performed in a user terminal.

It is another object of the present invention to provide an information security method using key synchronization performed in a service providing server.

It is another object of the present invention to provide an information security method using key synchronization.

According to an aspect of the present invention, there is provided an information security method using key sharing, the method comprising: receiving a request for processing confidential information, the request being performed by a user terminal; Extracting a key for generating a token corresponding to the information, and generating a token corresponding to the confidential information using the extracted key.

Here, the key pool of the user terminal may be stored with a key issued from a key server.

Here, the key pool of the user terminal may be constituted by a key derived by applying a unique value of the user terminal to the key issued to the service providing server interlocked with the user terminal.

Here, the user terminal further includes a step of updating the key pool of the user terminal according to the extracted key, before or after the step of generating the token corresponding to the confidential information using the extracted key can do.

Here, the step of updating the key pool of the user terminal according to the extracted key may include extracting the extracted key from the key pool of the user terminal or displaying whether or not to extract the extracted key, Can be stored in the key pool of the user terminal.

Here, after the user terminal generates the token corresponding to the confidential information using the extracted key, it may further include transmitting the generated token and the key related information to the service providing server linked with the user terminal have.

According to another aspect of the present invention, there is provided an information security method using key synchronization, the method comprising: receiving a token and key related information from a user terminal; Extracting a key corresponding to the key-related information from the key pool of the service providing server, and restoring the received token to confidential information using the extracted key.

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

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

The recovering of the received token using the extracted key to confidential information may include generating a key synchronized with the user terminal using the extracted key and the key related information, The token can be restored to confidential information.

The method may further include updating the key pool of the service providing server as a step before or after the step of restoring the received token to confidential information using the extracted key.

According to another aspect of the present invention, there is provided an information security method using key synchronization, the method comprising: issuing a key to a user terminal and a service provision server, the key server requesting processing of confidential information, Extracting a key for generating a token corresponding to the confidential information from the key pool of the key pool; generating a token corresponding to the confidential information using the extracted key by the user terminal; Extracting a key from the key pool of the service providing server using the key related information transmitted from the service providing server, and transmitting the key to the service providing server using the key extracted from the key pool of the service providing server And recovering the confidential information from the token received from the user terminal.

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

Herein, as a step before or after the step of generating the token corresponding to the confidential information by using the extracted key, the user terminal extracts the key pool of the user terminal according to the key extracted from the key pool of the user terminal key pool) of the user.

Here, the step of updating the key pool of the user terminal may include extracting the extracted key from the key pool of the user terminal or displaying whether the extracted key is extracted, The key can be stored in the key pool of the user terminal.

Here, the step of restoring confidential information from the token received from the user terminal using the key extracted from the key pool of the service providing server by the service providing server may include the steps of: Generate a synchronized key, and recover the received token using the synchronized key.

Here, as a step before or after the step of restoring the confidential information from the transmitted token, the service providing server transmits the key pool of the service providing server key pool) of the user.

When using the information security method using the key synchronization according to the present invention as described above, since the token is generated and decrypted at the transmitting / receiving end without the token server, the risk of security can be dispersed.

Also, even if the key is exposed in the key server, since the token is exchanged only at the transmitting and receiving end, confidential information is not exposed, and the equipment can be relatively easily repaired and replaced by replacing the key pool.

In addition, due to the key synchronization, the key itself does not need to be transmitted other than when the key is issued. Therefore, even if the key-related information is leaked in the process of transferring from the user terminal to the service providing server, the key can not be known without the key pool, so that the security problem in the transmission process can be more easily coped with.

1 is a block diagram showing a configuration of an existing tokenizing technique.
2 is a block diagram illustrating an information security method using key synchronization according to an embodiment of the present invention.
3 is a block diagram illustrating a transmitter and a receiver for performing an information security method using key synchronization according to an embodiment of the present invention.
4 is a flowchart illustrating an information security method using key synchronization performed in a user terminal according to an embodiment of the present invention.
5 is a flowchart illustrating an information security method using key synchronization performed in a service providing server according to an embodiment of the present invention.
6 is a sequence diagram illustrating an information security method using key synchronization according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terms first, second, A, B, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

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

2 is a configuration diagram illustrating a configuration of an information security method using key synchronization.

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

First, a user terminal as a transmitting terminal 100 generates a token from confidential information using a key issued from the key server 200, and transmits the token and key related information to the receiving terminal 300. Here, the user terminal may refer to a smart phone, a tablet PC, a notebook computer, a smart home appliance, a POS terminal, or a device providing IoT service in which a card payment app is driven, but the present invention is not limited thereto, May correspond to various communication devices.

Also, the key server 200 can generate and store a key as a server device capable of short-range or long-distance communication using a wired or wireless network, and can issue keys generated in the transmitting terminal 100 and the receiving terminal 300.

The service providing server, which is the receiving terminal 300, may be various server devices connected to a wired / wireless network such as a credit card company server and an online server that provides IoT service. However, the present invention is not limited thereto. Based on this, the token can be interpreted to confirm confidential information.

For example, the transmitting terminal 100 may be a card settlement device held by a card merchant, and the receiving terminal 300 may be a server of a card company that performs card settlement.

Specifically, the owner of the card merchant shop can perform payment according to the payment request of the customer using the transmitting terminal 100. [ In this process, the payment information of the customer including the card number is collected and notified to the card company server.

When a payment request is received to transmit the payment request, the transmitting terminal 100 generates a token using the payment information of the customer and one of keys previously issued (1) from the key server 200, and updates the key pool (2). Thereafter, the token is transmitted to the receiving end 300 together with the key related information used for generating the token ([3]). After receiving the key-related information and the token, the receiving terminal 300 extracts the key using the key-related information in the key pool. The extracted key is used to restore the token back to the customer's payment information and update the key pool (4), and the card company can perform the settlement service using the restored payment information.

3 is a block diagram illustrating a transmitter and a receiver for performing an information security method using key synchronization according to an embodiment of the present invention.

Referring to FIG. 3, the roles of the transmitter 100 and the receiver 300 will be described in more detail.

The transmitting terminal 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 composed of one or more keys transmitted from the key server 200. Also, when key extraction is performed, the key pool 110 may update the key information to reflect the extracted information and store a new key. The details of the update process will be described later.

The key extracting unit 120 may extract a key to be used in generating the token in the key pool 110. The extracted key is used to generate a token in the token generating unit.

The token generating unit 130 may generate the token corresponding to the confidential information using the key extracted by the key extracting unit. Here, the token is a means for replacing confidential information. Even if it is leaked to the outside, the confidential information can not be known.

Information on the key extracted by the key extracting unit 120, that is, the key related information and the token generated by the token generating unit 130 are transmitted to the receiving terminal 300. [

The receiver 300 may include a key pool 110, a key extraction unit 120, and an information restoration unit 130.

The key pool 310 may share a common key with the key pool 110 in the transmitting terminal 100, but may have a different key, as a kind of storage composed of the keys received from the key server 200. Key information update can be performed as in the transmitting terminal 100. [

The key extracting unit 320 extracts a key from the key pool 310 using the key related information transmitted by the transmitting terminal 100. The key extracting unit 320 extracts a key from the key pool 310, Function.

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

4 is a flowchart illustrating an information security method using key synchronization performed in a user terminal.

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

In addition, confidential information may include, but is not limited to, personal information requiring the user to keep confidential such as credit card number, account number, financial information, medical record, criminal record, certification record, stock transaction or loan record . Here, the processing request of the confidential information may be requested by, for example, an application driven on the user terminal according to the user's electronic commerce transaction, or may be requested by the card terminal in the off-line store.

Herein, the user terminal may have a unique value that can be distinguished from other user terminals. The eigenvalue may be an identification (ID) of the user terminal, and may be unique It can mean the symbol that makes. In addition, the key pool ID and the transfer counter may be held. The ID of the key pool is a unique identifier of the key pool of the user terminal in distinguishing it from other user terminals, and the transmission counter may mean a number or a symbol used for key synchronization.

A key for generating a token corresponding to confidential information is extracted from a key pool of the user terminal (S120). Here, the key pool may store a key issued from a key server. In this case, the fact that it is issued from the key server does not necessarily mean that the key must be received directly from the key server, it may have a key issued by the key server at the time of manufacturing the user terminal, A key may be stored in the key pool of the user terminal.

In addition, the key server may give a key validity period to the issued key for the sake of security, or may not use the previously issued key after expiration of the validity period, and issue a new key again.

Here, the key pool of the user terminal may consist of a key derived by applying a unique value of the user terminal to a key issued to the service providing server. Here, various encryption algorithms can be used for deriving the key. Specifically, for example, a triple data encryption algorithm (TDEA) 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 can derive the key issued from the key server by the user terminal using the key extracted from the key pool of the service providing server . That is, the key to be used in the service providing server can be synchronized with the key of the user terminal.

Accordingly, it is possible to reduce the difficulty of frequently synchronizing the key pool with the user terminal and the service providing server, and to reduce the problem that the user-provided server has to hold and manage a separate key pool for each user terminal. Also, unlike the service providing server, the user terminal can extract the key from its own key pool and use it without additional computation, so the load on the user terminal is not large.

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

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

Here, extracting the key required for generating the token from the key pool may be performed in accordance with a preset order, or the stored key may be extracted first. In addition, the transmission counter of the user terminal may be used to extract a key corresponding to the transmission counter. At this time, the transfer counter is a number that increases one by one each time a key is used for generating 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 service providing server, As shown in FIG.

However, this is merely an example, and various means for synchronizing the key with the service providing server may be used.

And generates a token corresponding to the confidential information using the extracted key (S130). Here, the generation of the token may be implemented by, for example, a Random Number Generator (RNG) using a key, or an encryption. In this case, it is necessary not to know the confidential information from the token, but also to generate different confidential information with different tokens and not to have more than two confidential information in the same token.

In addition, for compatibility with existing systems, it is advantageous to generate a token having the same attribute as the attribute or data length or type of confidential information. In order to maintain the same attribute, for example, a format preserving encryption (FRE) may be applied.

The key pool may be updated according to the extracted key before or after the step (S130) of generating the token corresponding to the confidential information by using the extracted key of the user terminal.

Here, the method of updating the key pool can exclude the extracted key from the key pool or display whether or not to extract the extracted key, and selectively store the generated key using the extracted key in the key pool. For example, a one-way encryption or hash function can be used, and a transmission counter previously held by the user terminal can be used together. At this time, the generated key is stored in the key pool as a key to be used in the next transmission, and the transmission counter can be stored so as to correspond to each other.

More specifically, for example, a key can be generated by unidirectionally encrypting the extracted key by the number of transmission counters. In this case, the service providing server derives the key used by the user terminal using the transmission counter I can do it.

In the case of generating a key, the number of keys in the key pool of the user terminal after the key extraction may be equal to or less than a preset number, or may be generated at each update.

In the case where the user terminal can directly generate and use the key, the difficulty of issuing the key frequently from the key server and synchronizing with the service providing server can be reduced.

However, it is not necessarily required to follow such a method, but a key corresponding to a key stored in a key pool of a service providing server may be updated from a key server to a method of receiving a key.

In addition, the token and the key related information generated after generating the token (S130) may be transmitted to the service providing server (S140). Here, the key-related information may include information on a location or a method capable of identifying or deriving a key used for extracting and generating a token from the key pool. For example, the key-related information may include a unique value held by the user terminal, And may include a synchronization symbol for deriving the key.

5 is a flowchart illustrating an information security method using key synchronization performed in a service providing server.

Referring to FIG. 5, the service providing server receives token and key related information from a user terminal (S210). Here, the key-related information may include information on a location or a method capable of identifying or deriving a key used for extracting and generating a token from the key pool. For example, the key-related information may include a unique value held by the user terminal, And may include a synchronization symbol for deriving the key.

And extracts the key from the key pool of the service providing server using the received key related information (S220). Here, the key pool of the service providing server may store a key issued from a key server.

Here, when issuing the key of the key server, a secure channel or data encryption can be employed.

Also, in setting the key pool of the service providing server at this time, it is advantageous that a sufficient number of keys are included so as not tokenize or detoke the two or more confidential information with one key.

Here, the key extraction method can extract a key corresponding to the key pool of the user terminal using the key-related information. Specifically, the eigenvalue of the user terminal can be obtained from the key-related information and the corresponding key can be extracted. Means that the corresponding user terminal can derive the key issued from the key server by applying the unique value of the user terminal to the extracted key.

The received token is recovered as confidential information using the extracted key (S230). In more detail, a key synchronized with the user terminal may be generated using the extracted key and the key-related information, and the received token may be restored to confidential information using the synchronized key.

For example, first, an eigenvalue 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 to be converted. Through this conversion, the user terminal can obtain the key issued from the key server. Here, various encryption algorithms can be used as the conversion method. Specifically, for example, a triple data encryption algorithm (TDEA) encryption algorithm can be applied.

However, if the user terminal uses the key issued from the key server as it is, it can be restored as it is, but if the key is generated and used by itself, the key used for tokenization can not be known. Accordingly, the information used by the user terminal to generate the key can be obtained through the key-related information, and the key used for tokenizing the user terminal can be derived using the information. Specifically, after extracting a synchronization symbol such as a transfer counter from key-related information, a key used by the user terminal can be derived using the same method as that of the user terminal generating the key.

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

Here, in the case where the renewal is performed, when the validity period of the extracted key has passed, when the transmission counter in the received key-related information exceeds a predetermined number, when a security risk is detected in the user terminal or the service providing server Can be.

In this case, in the updating method, a key is issued to the service providing server by requesting the key server to issue a key, and a new key may be issued again to the user terminal.

6 is a sequence diagram of an information security method using key synchronization performed by a key server, a user terminal, and a service providing server in cooperation with each other.

The overall interaction relationship of the key server, the user terminal, and the service providing server will be described with reference to FIG.

First, the key server issues a key to the user terminal and the service providing server (S300-1, S300-2). Accordingly, 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 consist of a key derived by applying a unique value of the user terminal to a key issued to the service providing server.

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

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

Also, before or after the token generation (S330), the user terminal can update the key pool of the user terminal according to the key extracted from the key pool of the user terminal (S340). Here, it is possible to exclude the extracted key from the key pool of the user terminal, to indicate whether or not to extract the extracted key, and to store the generated key using the extracted key in the key pool of the user terminal.

The user terminal transmits the generated token and the key-related information to the service providing server (S350).

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

The service providing server restores the confidential information from the token received from the user terminal using the key extracted from the key pool set in the service providing server (S370). More specifically, Generate a key synchronized with the terminal, and recover the received token using the synchronized key.

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

According to the embodiment of the present invention described above, the service providing server can restore confidential information from the received token using the key extracted from the key pool set in the service providing server, Since the token is generated and decrypted, the risk of security can be dispersed.

Also, even if the key is exposed in the key server, since the token is exchanged only at the transmitting and receiving end, confidential information is not exposed, and the equipment can be relatively easily repaired and replaced by replacing the key pool.

In addition, due to the key synchronization, the key itself does not need to be transmitted other than when the key is issued. Therefore, even if the key-related information is leaked in the course of transmission from the user terminal to the service providing server, the key can not be known, so that the security problem in the transmission process can be more easily coped with.

The configuration of the user terminal, the key server 200, and the service providing server 300, which is the transmitting terminal 100 according to the embodiment of the present invention, has been described as a component for convenience of explanation. However, At least two of them may be combined to form one component or one component may be divided into a plurality of components to perform a function. In the case of the integrated and separate embodiments of the components, It is included in the scope of right.

The operation of the service providing server which is the user terminal, the key server 200, and the receiving terminal 300 according to the embodiment of the present invention can be realized by a computer readable program or code in a computer- As shown in FIG. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. The computer-readable recording medium may also be distributed and distributed in a networked computer system so that a computer-readable program or code can be stored and executed in a distributed manner.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

10: user terminal 20: token server
30: Token store 40: Service providing server
100: transmitting end 110: key pool
120: Key extraction unit 130: Token generation unit
200: Key server 300: Receiver
310: key pool 320: key extracting unit
330:

Claims (17)

An information security method using key synchronization performed by a user terminal,
Receiving a processing request of confidential information;
Extracting a second key for generating a token corresponding to the confidential information from a key pool of the user terminal; And
Generating a token corresponding to the confidential information using the extracted second key; And
Related information including the token, the transmission counter, and the eigenvalue of the user terminal to a service providing server operatively associated with the user terminal,
As a step before or after the step of generating the token,
And updating the key pool of the user terminal using the extracted third key by encrypting the extracted second key,
Wherein the transmission counter is a number that increases each time the token is generated and transmitted. The method according to claim 1,
Wherein the key pool of the user terminal stores a key issued from a key server. The method of claim 2,
Wherein the key pool of the user terminal comprises the second key derived by applying an eigenvalue of the user terminal to a first key issued to a service providing server interlocked with the user terminal, Security method. The method according to claim 1,
Wherein updating the key pool of the user terminal comprises:
And unidirectionally encrypting the extracted second key to derive a third key. The method according to claim 1,
Wherein updating the key pool of the user terminal comprises:
Wherein the second key is extracted from the key pool of the user terminal, or whether the second key is extracted or not. delete An information security method using key synchronization performed by a service providing server,
Receiving a token from the user terminal, key related information including a unique value of the user terminal and a transmission counter;
Extracting a first key from a key pool of the service providing server; And
And restoring the received token to confidential information using a third key derived by using the key related information in the first key,
Wherein the transmission counter is a number incremented by one each time the token is generated and transmitted from the user terminal. The method of claim 7,
Wherein the key pool of the service providing server stores the first key issued from a key server. The method of claim 8,
Wherein the key pool of the user terminal comprises a second key derived by applying an eigenvalue of the user terminal to the first key issued to the service providing server. The method of claim 7,
The step of restoring the received token into confidential information includes:
And applying a unique value of the user terminal to the first key to derive a second key. The method of claim 10,
Wherein deriving the second key comprises:
And unidirectionally encrypting the second key to derive the third key. In an information security method using key synchronization,
The key server issuing a key to the user terminal and the service providing server;
Extracting a second key for generating a token corresponding to the confidential information from the key pool of the user terminal in response to the user terminal requesting the processing of confidential information;
The user terminal generating the token corresponding to the confidential information using the second key;
Transmitting the key related information including the token, the transmission counter, and the unique value of the user terminal to the service providing server;
The service providing server receiving the token and the key related information from the user terminal;
The service providing server extracting a first key from a key pool of the service providing server; And
And restoring the received token to confidential information using a third key derived by using the key related information in the first key,
As a step before or after the step of generating the token,
And updating the key pool of the user terminal using the extracted third key by encrypting the extracted second key,
Wherein the transmission counter is a number incremented by one each time the token is generated and transmitted from the user terminal. The method of claim 12,
The key pool of the user terminal comprises:
And the second key derived by applying the eigenvalue of the user terminal to the first key issued to the service providing server. The method of claim 12,
The step of restoring the received token into confidential information includes:
And applying the eigenvalue of the user terminal to the first key to derive the second key. The method of claim 12,
Wherein updating the key pool of the user terminal comprises:
And extracting the extracted key from the key pool of the user terminal or displaying whether the extracted key is extracted. 15. The method of claim 14,
Wherein deriving the second key comprises:
And unidirectionally encrypting the second key to derive the third key. The method of claim 12,
As the step before or after the step of restoring to the confidential information,
Further comprising the step of the service providing server updating a key pool of the service providing server.

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