KR20170111809A - Bidirectional authentication method using security token based on symmetric key - Google Patents

Abstract

A two-way authentication method using a symmetric key-based security token is provided. A two-way authentication method using a symmetric key-based security token according to an embodiment of the present invention is a method in which a terminal encrypts a server authentication token generated by encrypting with a secret key of the terminal using a dynamic key generated by a shared key, step; The server decrypts the encrypted server authentication token with the dynamic key generated by the shared key, encrypts the token with the session key generated by the shared key and the dynamic key, encrypts the token using the secret key of the server itself, Encrypting with a dynamic key and requesting authentication with the terminal; The terminal decrypts the encrypted server authentication token with the session key generated using the shared key and the dynamic key, and decrypts the decrypted token with the secret key of the terminal to authenticate the server; Decrypting the encrypted terminal authentication token with a dynamic key, encrypting the encrypted terminal authentication token with a session key, and transmitting the encrypted token to the server to request terminal authentication; And decrypting the token encrypted by the server with the dynamic key, and decrypting the decrypted token with the server's own secret key to authenticate the terminal.

Description

[0001] The present invention relates to a bi-directional authentication method using a symmetric key based security token,

The present invention relates to a bi-directional authentication method using a security token based on a symmetric key, and more particularly, to a bi-directional authentication method using a symmetric key based security token for performing authentication using a security token without directly transmitting an encryption key between the server and the terminal To a bi-directional authentication method.

Keberos, which provides a fast symmetric key authentication method, performs authentication based on the assumption that a trusted key is shared between an authentication server, a ticket issuing server, and a service server. However, since this method performs only one-way authentication, there is a problem that it is very vulnerable to an attack against a server.

On the other hand, SSL (Secure Socket Layer) method, which provides two-way authentication for improving security, is asymmetric key based authentication method and is slower than symmetric key based method. Also, this method is a method of authenticating the server through the third certification authority, and therefore, if the certification authority is not trusted, authentication can not be performed stably.

Therefore, a symmetric key-based two-way authentication method is required in order to smoothly authenticate devices with low specification, such as the Internet (IoT) environment, where a user can not directly identify a certificate or a certification authority.

KR 1483895 B

According to an aspect of the present invention, there is provided a bi-directional authentication method using a security token based on a symmetric key capable of performing secure authentication even when the authentication server or the authentication authority is not trusted .

It is another object of the present invention to provide a two-way authentication method using a symmetric key-based security token, which can improve security by blocking spoofing attacks by a fake server using bidirectional authentication between a server and a terminal based on a security token .

The present invention also provides a two-way authentication method using a symmetric-key-based security token in which bidirectional authentication can be implemented based on a symmetric key, thereby improving processing speed.

According to an aspect of the present invention, there is provided a bi-directional authentication method using a symmetric key based security token. The bi-directional authentication method using the symmetric key-based security token includes encrypting the token generated by encrypting the terminal with the secret key of the terminal using the dynamic key generated by the shared key, and transmitting the encrypted token to the server to request the service; The server decrypts the server authentication token received from the terminal with the dynamic key generated by the shared key and then encrypts the shared key and the session key generated by the dynamic key using the secret key of the server itself Encrypting the generated terminal authentication token with the generated dynamic key, and transmitting the authentication result to the terminal together with the server authentication token encrypted with the session key to request server authentication; Decrypting the server authentication token received from the server with the shared key and the session key generated using the dynamic key, and then decrypting the decrypted server key with the secret key of the terminal to authenticate the server; Decrypting the terminal authentication token received from the server with the dynamic key, encrypting the terminal with the generated session key, and transmitting the encrypted session key to the server to request terminal authentication; And decrypting the terminal authentication token received from the terminal with the dynamic key, and decrypting the decrypted token with the secret key of the server using the dynamic key to authenticate the terminal.

In one embodiment, the dynamic key may be generated by a dynamic key generation algorithm and a shared key shared between the server and the terminal.

In one embodiment, the step of requesting the service and the step of requesting the terminal authentication may encrypt different random numbers with the dynamic key and transmit the same.

In one embodiment, the session key may be generated using further different random numbers.

In one embodiment, the bi-directional authentication method comprises: transmitting an ID of the terminal when the service is requested; Encrypting the ID of the terminal with the dynamic key and transmitting the encrypted ID; And authenticating the server by decrypting the ID of the encrypted terminal.

In one embodiment, the shared key may be an Authentication Requestor Security Key (ARSK).

In one embodiment, if the terminal is an Internet (IoT) device, the authentication requestor security key (ARSK) may be stored and shared in the server and the terminal.

In one embodiment, when the terminal is a user terminal, the authentication requestor security key (ARSK) is stored only in the server, and may not be stored in the terminal, but may be input upon generation of the dynamic key on a knowledge base.

In one embodiment, the Authentication Requestor Security Key (ARSK) may include at least one of a password and a fingerprint.

In one embodiment, the server includes a service server and an authentication server, wherein the steps are performed between the authentication server and the terminal, and the terminal authentication token includes a second And encrypting the decrypted terminal authentication token with the generated session key and transmitting the decrypted terminal authentication token to the service server to request a connection; And decrypting the terminal authentication token received from the terminal with the session key received from the authentication server and then decrypting the terminal authentication token with the second shared key to authenticate the terminal.

In one embodiment, the bi-directional authentication method comprises: the service server requesting the session key to the authentication server; And the authentication server encrypting the session key with the second shared key and transmitting the encrypted session key to the service server.

In one embodiment, the bi-directional authentication method comprises the steps of: transmitting, to the service server, verification information encrypted with a second session key generated by a third random number included in the session key and the terminal authentication token at the connection request; The service server obtaining the third random number from the decrypted terminal authentication token, generating the second session key with the session key and the third random number, and decrypting the verification information with the second session key ; Encrypting information calculated from the decrypted verification information with the second session key by using the second session key, and transmitting the encrypted information to the terminal; And checking the service server by decoding the calculated information by the terminal.

According to another aspect of the present invention, there is provided a method for encrypting a server, the method comprising: encrypting a token for server authentication generated by a secret key using a dynamic key generated by a shared key; Receiving the server authentication token encrypted with the session key from the server according to the request, generating the session key using the shared key and the generated dynamic key, and transmitting the received server authentication token to the generated session Authenticating the server by decrypting the decrypted data using the secret key; And transmitting the encrypted terminal authentication token to the server so that the server authenticates the terminal after receiving the encrypted terminal authentication token from the server, decrypting the encrypted terminal authentication token with the dynamic key, and encrypting the decrypted with the session key A two-way authentication method using a symmetric key-based security token is provided.

According to another aspect of the present invention, a server authentication token received according to a service request from a terminal is decrypted with a dynamic key generated by a shared key, and then the session key is encrypted using the shared key and the session key generated by the dynamic key, Encrypting the terminal authentication token generated by encrypting with the secret key using the generated dynamic key, and transmitting the encrypted token to the terminal together with the server authentication token encrypted with the session key to request server authentication; And receiving the terminal authentication token encrypted with the session key according to a terminal authentication request after the server authentication in the terminal, decoding the generated token using the generated dynamic key, and decrypting the token with the secret key to authenticate the terminal. Based authentication method using a security token is provided.

According to an embodiment of the present invention, in the two-way authentication using the security token based on the symmetric key, since the encryption key itself is not transmitted through the relatively weak network, the false attack by the fake server is originally blocked, The authentication stability can be improved even when the authentication server or the certification authority is not used separately or is not trusted.

In addition, the present invention can speed up the processing speed in bi-directional authentication by reducing the operation speed based on the symmetric key, and thus it is possible to provide not only high-grade terminals but also low-end terminals, thereby providing an authentication method suitable for the Internet of Things (IoT) environment.

1 is a block diagram illustrating an example of a system to which a two-way authentication method using a symmetric-key-based security token according to an embodiment of the present invention is applied.
FIG. 2 is a flowchart illustrating a registration procedure for a two-way authentication method using a symmetric-key-based security token according to an embodiment of the present invention.
FIG. 3 is a flowchart illustrating a two-way authentication method using a symmetric key based security token according to an embodiment of the present invention.
4 is a block diagram illustrating another example of a system to which a two-way authentication method using a symmetric-key-based security token according to an embodiment of the present invention is applied.
5 is a flowchart illustrating a two-way authentication method using a symmetric key based security token according to another embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

1 is a block diagram illustrating an example of a system to which a two-way authentication method using a symmetric-key-based security token according to an embodiment of the present invention is applied.

As shown in FIG. 1, a system to which a two-way authentication method using a symmetric key-based security token according to an embodiment of the present invention is applied includes a terminal 10 and a server 20.

The terminal 10 may access the server 20 and perform authentication for the server 20. [ Such a terminal 10 may include not only a user terminal such as a smart phone, a mobile phone or other portable device carried by the user, but also other devices such as a beacon, a gateway or other electronic device having a communication function, (IoT) device.

The server 20 can perform authentication of the terminal 10 according to a service request of the terminal 10. [ The server 20 may be a server having both an authentication function and a service providing function. That is, the server 20 may perform authentication for the terminal 10 and provide a service requested by the terminal 10.

Bidirectional authentication between the terminal 10 and the server 20 can be performed. That is, the terminal 10 performs authentication for the server 20, and the server 20 performs authentication for the terminal 10, so that the normal service can be provided only when both mutual authentication is completed.

At this time, each of the terminal 10 and the server 20 generates a dynamic key (Key_A) using a pre-shared dynamic key generation algorithm and an initially registered authentication requestor security key (ARSK) Mutual authentication can be performed using the session key (Key_B) according to the random numbers (R1, R2) to be transmitted and received.

Here, the terminal 10 and the server 20 may be connected through a communication network such as a public network, a private network, or an intranet. At this time, since the terminal 10 and the server 20 do not directly transmit the encryption key to each other for mutual authentication but use the security token, the leakage of the encryption key can be prevented in advance.

That is, even if the data transmitted and received between the terminal 10 and the server 20 are leaked, the dynamic key (Key_A) generated by each other is not known, or if the shared key (ARSK) It is possible to guarantee the stability from the meson attack.

FIG. 2 is a flowchart illustrating a registration procedure for a two-way authentication method using a symmetric-key-based security token according to an embodiment of the present invention.

As shown in FIG. 2, the terminal 10 registers a shared key (ARSK) in advance for bidirectional authentication with the server 20.

First, the terminal 10 requests connection to the server 20 (step S101).

At the same time, the terminal 10 and the server 20 share a dynamic key generation algorithm (step S102). For example, when the terminal 10 requests connection to the server 20, it can share the same dynamic key generation algorithm through program installation or the like. The dynamic key generation algorithm may be installed in advance in each of the terminal 10 and the server 20.

That is, the process of registering the terminal 10 in the server 20 as described above may be performed online or offline.

Here, the server 20 performs authentication of the terminal through user authentication (step S103). At this time, the terminal 10 can transmit the authentication requestor security key (ARSK) to the server 20 as information of the authentication requester (step S104).

The authentication requester security key (ARSK) may be a security key generated in the terminal 10, but it is not limited thereto and may be knowledge-based information. In particular, when the terminal 10 is a user terminal, it may be knowledge base information such as a password and a fingerprint that can be directly input by the user.

The server 20 stores the authentication requester security key ARSK as a shared key (step S105).

At this time, if the terminal 10 is an Internet Internet (IoT) device such as a beacon or a gateway, the terminal 10 may store the authentication requester security key ARSK (step S106).

Alternatively, if the terminal 10 is a user terminal such as a smart phone or a mobile device, the authentication supplicant security key (ARSK) may be used as a knowledge base without being stored in the terminal 10. [ That is, the terminal 10 can directly receive an authentication requestor security key (ARSK) upon registration to the server 20 or upon generation of a dynamic key (Key_A) for authentication.

As described above, the dynamic key generation algorithm and the authentication requestor security key (ARSK) when the terminal 10 is initially registered in the server 20 can be shared between the terminal 10 and the server 20. [

FIG. 3 is a flowchart illustrating a two-way authentication method using a symmetric key based security token according to an embodiment of the present invention.

As shown in FIG. 3, the two-way authentication method 200 using a symmetric key-based security token is an authentication method when the server 20 has an authentication function and a service providing function without requiring a separate authentication server.

First, the terminal 10 generates a dynamic key (Key_A) by a dynamic key generation algorithm shared with the server 20 (step S201). At this time, the terminal 10 can generate a dynamic key (Key_A) using a shared key (ARSK). Here, if the shared key (ARSK) is knowledge-based, the terminal 10 can receive a shared key (ARSK) from the user. Also, if the shared key (ARSK) is not knowledge-based, i.e. stored at the time of initial registration, the terminal 10 may use the stored shared key (ARSK).

In addition, the terminal 10 generates a token Token_A for server authentication (step S202). At this time, the terminal 10 can generate a token (Token_A) for server authentication by encrypting it with its secret key.

Here, the secret key may be generated by the terminal 10 itself with a predetermined length by an encryption algorithm. For example, the input information such as a password or a fingerprint can be generated using a secret key of a predetermined length by performing a hash algorithm operation.

The generated server authentication token Token_A may include a token authenticator TA1 that has performed a token expiration date, server information, a sequence number, and a hashed message authentication code (HMAC) It is not limited.

Meanwhile, the HAMC operation is an operation for verifying the integrity of whether the contents of the token contents are unchanged, and the token authenticator TA1 is a result calculated by performing the HMAC operation. In this case, the data integrity verification method is performed by comparing the MAC value. For example, the content of the token is compared with the token authenticator TA1 by performing the HMAC operation. Then, the MAC and the token authenticator (TA1). ≪ / RTI > Since the actual information of the server authentication token Token_A is encrypted by the secret key of the terminal 10 itself, the server 20 can not know the actual information and only the terminal 10 can verify the actual information have. Accordingly, the bi-directional authentication method 200 of the present embodiment can ensure stability from the meson attack on the network.

Optionally, the terminal 10 may generate a first random number R1 for generating a session key (Key_B).

Next, the terminal 10 encrypts the generated server authentication token Token_A with the dynamic key (Key_A) generated by the shared key (ARSK) and requests the server 20 for the service (step S203). That is, the terminal 10 transmits a token (Token_A) for server authentication encrypted with the dynamic key (Key_A) at the time of the service request to the server 20. Here, the terminal 10 can transmit its ID to the server 20.

At this time, when the first random number R1 is generated, the terminal 10 can encrypt the first random number R1 with the dynamic key (Key_A) and transmit it to the server 20.

As described above, the server authentication token Token_A is double-encrypted by the secret key of the terminal 10 and the dynamic key (Key_A), so that even when the server authentication token Token_A is intercepted on the network, , It is possible to block illegal meson attacks.

The server 20 receiving the service request generates the same dynamic key (Key_A) as the server 20 using the same dynamic key generation algorithm as that of the terminal 10 (step S204). At this time, the server 20 can generate the dynamic key (Key_A) with the shared key (ARSK). Here, if the shared key (ARSK) is knowledge-based, the server 20 receives the shared key (ARSK) from the user and verifies the authenticity of the shared key (ARSK) registered first. Also, if the shared key (ARSK) is not knowledge based, the server 20 can use the stored shared key (ARSK) at the time of initial registration.

Then, the server 20 decrypts the server authentication token (Token_A) received from the terminal 10 with the generated dynamic key (Key_A) (step S205). Since the server 20 decrypts the server authentication token Token_A with the dynamic key Key_A but the server authentication token Token_A is encrypted with the secret key of the terminal 10, The actual information of the token (Token_A) is unknown.

At this time, when the terminal 10 generates and transmits the first random number R1, the server 20 can decrypt the first random number R1 with the dynamic key Key_A.

The server 20 generates a session key (Key_B) using the dynamic key (Key_A) and the shared key (ARSK) (step S206). Here, the session key (Key_B) is a key for encrypting the server authentication token (Token_A) received from the terminal (10) by the server (20).

Alternatively, when the server 20 generates the first random number R1 and the second random number R2 in the terminal 10 and the server 20, respectively, the server 20 generates the first random number R1 and the second random number R2, The session key Key_B can be generated by using the random number R2 together with the dynamic key Key_A and the shared key ARSK. Here, the first random number Rl and the second random number R2 may be different from each other.

Subsequently, the server 20 generates a token Token_B for terminal authentication (step S207). At this time, the server 20 can generate a terminal authentication token (Token_B) by encrypting it with its own secret key.

This secret key can be generated by the server 20 itself with a certain length by an encryption algorithm. For example, the input information such as a password or a fingerprint can be generated with a secret key of a predetermined length by performing a hash algorithm algorithm.

The generated terminal authentication token Token_B may include a token expiration date, an authentication requester ID, an access mode, a sequence number, and a token authenticator TA1 that performs an HMAC operation. Do not.

Since the actual information of the terminal authentication token Token_B is encrypted by the secret key of the server 20 itself, the terminal 20 can not know the actual information and only the server 20 can authenticate the information have.

The server 20 transmits the server authentication token Token_A and the terminal authentication token Token_B to the terminal 10 using the generated dynamic key Key_A and the session key Key_B, (Step S208).

At this time, the server 20 encrypts the terminal authentication token (Token_B) with the dynamic key (Key_A), encrypts the server authentication token (Token_A) with the session key (Key_B) The terminal authentication token Token_B and the server authentication token Token_A.

Here, when the terminal 10 transmits the authentication requestor ID, that is, the terminal 10, the server 20 can encrypt the ID with the dynamic key (Key_A) and transmit the encrypted ID to the terminal 10.

At this time, when the second random number R2 is generated, the server 20 can encrypt the second random number R2 with the dynamic key (Key_A) and transmit it to the terminal 10.

In this manner, the terminal authentication token Token_B is double-encrypted by the secret key of the server 20 and the dynamic key (Key_A), so that even when the terminal authentication token Token_B is intercepted on the network, It is possible to stably block the illegal meson attack.

Then, the terminal 10 decrypts the server authentication token Token_A received from the server 20 with the generated dynamic key (Key_A) (step S209). Since the terminal 10 decrypts the terminal authentication token Token_B with the dynamic key Key_A and the terminal authentication token Token_B is encrypted with the secret key of the server 20, The actual information of the usage token (Token_B) is unknown.

At this time, when the server 20 generates and transmits the second random number R2, the terminal 10 can decrypt the second random number R2 with the dynamic key Key_A.

When the server 20 encrypts the authentication requestor ID, the terminal 10 decrypts the authentication requestor ID using the generated dynamic key (Key_A) to verify the ID of the terminal 10 (Step S210) .

That is, the terminal 10 can authenticate the server 20 when the ID transmitted by the terminal 10 and the ID received and decoded from the server 20 are the same. At this time, if the decrypted ID is different from the ID of the terminal 10, the terminal 10 can notify the server 20 of the server authentication failure (step S210 ').

The terminal 10 generates a session key (Key_B) using the generated dynamic key (Key_A) and the shared key (ARSK) (step S211). Here, the session key (Key_B) is a key for decrypting the server authentication token (Token_A) encrypted and transmitted by the server (20).

Alternatively, when the terminal 10 and the server 20 generate the first random number R1 and the second random number R2, respectively, the terminal 10 generates the first random number R1 and the decrypted second random number R2, A random number R2 can be used together with a dynamic key Key_A and a shared key ARSK to generate a session key Key_B.

The terminal 10 decrypts the server authentication token Token_A received from the server 10 using the generated session key (Key_B) (step S212).

Also, the terminal 10 decrypts the server authentication token Token_A decrypted with the session key (Key_B) with its own secret key to authenticate the server 20 (step S213). That is, the terminal 10 can confirm all details of the decrypted server authentication token Token_A. Therefore, the terminal 10 can authenticate the server 20 according to whether or not the terminal 10 is the same as the one issued by the terminal 10 itself.

At this time, if the decrypted server authentication token (Token_A) is different from the server authentication token (Token_A) issued by the terminal 10, the terminal 10 can notify the server 20 of the server authentication failure (step S213 ') . Here, the terminal 10 may determine that the dynamic key (Key_A) used when transmitting the server authentication token (Token_A) transmitted through the network is intercepted in the middle and failed to share with the server 20 .

That is, when the terminal 10 encrypts and decrypts the server authentication token (Token_A) transmitted from the server 20 to the server 10, the counterpart receives a normal server authentication token Token_A ) Is not transmitted. Accordingly, when the verification result of the token (Token_A) for server authentication is different, the terminal 10 can determine that the server authentication is failed.

Thus, even when the sharing of the dynamic key (Key_A) transmitted on the network fails, the server authentication token (Token_A) itself is encrypted with the secret key of the terminal 10 itself, so that the intermediator attack can be blocked.

The terminal 10 that has performed the server authentication transmits the server authentication result to the server 20 and requests the terminal authentication (step S214). At this time, the terminal 10 can encrypt the decrypted terminal authentication token (Token_B) with the generated session key (Key_B) and transmit it to the server 20. Also, the terminal 10 may encrypt the server authentication result with the session key (Key_B) and transmit the same.

The server 20 receiving the encrypted terminal authentication token Token_B from the terminal 10 decrypts the received terminal authentication token Token_B (step S215). At this time, the server 20 can decrypt the terminal authentication token (Token_B) using the generated session key (Key_B).

In addition, the server 20 decrypts the terminal authentication token Token_B decrypted with the session key (Key_B) with its secret key to authenticate the terminal 10 (step S216). That is, the server 20 can confirm all details of the decrypted terminal authentication token (Token_B). Therefore, the server 20 can authenticate the terminal 10 according to whether or not the server 20 itself is the same as the one generated.

At this time, if the decrypted terminal authentication token (Token_B) is different from the terminal authentication token (Token_B) issued by the terminal 20, the server 20 can notify the terminal 10 of the terminal authentication failure (step S216 '). .

The server 20 that has performed the terminal authentication transmits the terminal authentication result to the terminal 10 (step S217).

According to this method, bidirectional authentication between the terminal 10 and the server 20 can be performed quickly and stably without a separate authentication server or an authentication authority.

In addition, since the fake attack by the fake server is originally blocked, the authentication stability can be improved even when the authentication server or the certification authority is not separately used or trusted.

In addition, since the processing speed in bi-directional authentication is increased, authentication can be performed not only for high-grade terminals but also for low-end terminals, thereby providing an authentication method suitable for the Internet of Things (IoT) environment.

4 is a block diagram illustrating another example of a system to which a two-way authentication method using a symmetric-key-based security token according to an embodiment of the present invention is applied.

4, a system to which a bi-directional authentication method using a symmetric key based security token according to an embodiment of the present invention is applied includes a terminal 10, an authentication server 20, and a service server 30.

Here, the authentication server 20 and the service server 30 may be simply a physically separated function of the server 20 of FIG. That is, the authentication server 20 of FIG. 4 does not generally refer to an authentication specialized server connected through an external network, and may be a part of a server connected through an internal network or a single communication line.

For example, when providing a large variety of services provided by the server 20 of FIG. 1, a service server may be provided for each unit service, and an authentication server for authentication of the service server may be provided can do.

At this time, the terminal 10 may be connected to the authentication server 20 and the service server 30 through a communication network such as a public network, a private network, or an intranet.

Here, as described with reference to FIGS. 1 to 3, the terminal 10 can perform bidirectional mutual authentication with the authentication server 20.

When the authentication of the terminal 10 and the authentication server 20 is completed, the terminal 10 performs a connection request to the service server 30, and the service server 30 transmits a connection request to the terminal 30 via the authentication server 20, By performing the authentication, substantial authentication between the terminal 10 and the service server 30 can be completed. At this time, the service server 30 can normally transmit data to the terminal 10.

1, the authentication server 20 shares its own secret key (Key_C), which is used when generating the terminal authentication token Token_B, with the service server 30. That is, not only the authentication server 20 but also the service server 30 must perform the terminal authentication, respectively, so that the service server 30 can also confirm the terminal authentication token Token_B issued by the authentication server 20 The secret key (Key_C) must be shared.

5 is a flowchart illustrating a two-way authentication method using a symmetric key based security token according to another embodiment of the present invention. In FIG. 5, steps that perform the same functions as those of FIG. 3 are denoted by the same reference numerals. In the following description, the same parts as those of FIG. 3 will be briefly described and different parts will be mainly described.

As shown in FIG. 5, the two-way authentication method 300 using a symmetric key-based security token is an authentication method when the server is physically divided into an authentication server and a plurality of service servers.

First, a registration process 100 as shown in FIG. 2 is performed between the terminal 10 and the authentication server 20.

At this time, the authentication server 20 and the service server 30 form a secure channel and share a second shared key (Key_C) as a secret key (step S301). Here, since the authentication server 20 and the service server 30 are disposed close to each other without using an external network, a secure channel can be formed.

Thereafter, mutual authentication between the terminal 10 and the authentication server 20 as shown in Fig. 4 is started. First, the terminal 10 generates a dynamic key (Key_A) and an encrypted server authentication token (Token_A), encrypts the server authentication token (Token_A) with a dynamic key (Key_A) (Step S201 to step S203).

The authentication server 20 generates a dynamic key (Key_A) identical to the terminal 10 to decrypt the server authentication token Token_A into the generated dynamic key (Key_A) and encrypt the terminal authentication token Token_B And generates a session key (Key_B) (steps S204 to S206).

At this time, the authentication server 20 generates a token Token_B for terminal authentication (step S307). Here, the authentication server 20 may generate a terminal authentication token (Token_B) by encrypting it with a second shared key (Key_C) which is a secret key shared with the service server 30.

The generated terminal authentication token Token_B includes the token expiration date, the authentication requester ID, the access mode, the sequence number, the service server ID in addition to the token authenticator TA1 for performing the HMAC operation, the third random number R3 May be further included. However, the content of the terminal authentication token Token_B is not limited to this.

Since the actual information of the terminal authentication token Token_B is encrypted by the second shared key (Key_C) of the authentication server 20 and the service server 30, actual information is not known in the terminal 10, Only the authentication server 20 and the service server 30 can verify the actual information. Accordingly, the bi-directional authentication method 300 of the present embodiment can guarantee stability from the meson attack on the network.

The authentication server 20 transmits the server authentication token Token_A and the terminal authentication token Token_B to the terminal 10 to request terminal authentication (step S308). At this time, the authentication server 20 encrypts the terminal authentication token Token_B with the dynamic key Key_A, encrypts the server authentication token Token_A with the session key Key_B, An authentication token (Token_B) and a server authentication token (Token_A).

Here, the authentication server 20 may encrypt the ID and the second random number R2 of the terminal 10 using the dynamic key (Key_A) and transmit it to the terminal 10. The authentication server 20 can encrypt the third random number R3 for generating the second session key Key_D for connection with the service server 30 by encrypting the third random number R3 with the session key Key_B have.

The third random number R3 is the same as that included in the terminal authentication token Token_B and the service server 30 can know the actual content of the terminal authentication token Token_B so that the third random number R3 is The terminal 10 does not need to separately transmit it, but the authentication server 20 must transmit it to the terminal 10 because the terminal 10 can not know the actual content of the terminal authentication token Token_B.

Thereafter, the terminal 10 decrypts the terminal ID, the terminal authentication token Token_B, authenticates the authentication server through the ID verification, generates the session key Key_B, generates the server authentication token Token_A, To the generated session key (Key_B) to perform authentication of the authentication server (steps S209 to S213).

At this time, when the server 20 transmits the third random number R3 to the terminal 10, the terminal 10 can decrypt the third random number R3 with the session key (Key_B).

Then, when the terminal 10 transmits the authentication result to the authentication server 20 and requests the terminal authentication, the server 20 decrypts the terminal authentication token Token_B to perform terminal authentication and transmits the authentication result to the terminal 10 (Steps S214 to S217).

When the two-way authentication between the terminal 10 and the authentication server 20 is completed, the terminal 10 generates a second session key (Key_D) (step S318). At this time, the terminal 10 may generate the second session key (Key_D) with the session key (Key_B) and the third random number (R3).

Here, the second session key (Key_D) is a key for performing verification between the terminal 10 and the service server 30.

The terminal 10 encrypts the decrypted terminal authentication token Token_B with the session key (Key_B) and transmits the decrypted terminal authentication token to the service server 30 (step S319). At this time, the terminal 10 can encrypt the verification information S with the decrypted third random number R3 and transmit the encrypted verification information S to the service server 30.

Then, the service server 30 requests the authentication server 20 for a session key (Key_B) (step S320). At this time, the service server 30 requests the session key (Key_B) using the authentication requestor ID, i.e., the ID of the terminal.

The authentication server 20 having received the session key (Key_B) transmits the session key (Key_B) to the service server 30 (step S321). At this time, the authentication server 20 can encrypt the session key (Key_B) with the second shared key (Key_C), which is a secret key shared with the service server (30).

Upon receiving the encrypted session key (Key_B), the service server (30) decrypts the encrypted terminal authentication token (Token_B) using the second shared key (Key_C) (Step S322).

That is, the service server 30 can confirm all details of the decrypted terminal authentication token (Token_B). Accordingly, the service server 20 can authenticate the terminal 10 according to whether or not the authentication server 20 is the same as the one generated.

At this time, if the decrypted terminal authentication token (Token_B) is different from the terminal authentication token (Token_B) issued by the authentication server 20, the service server 20 can notify the terminal 10 of the terminal verification failure (Step S322 ').

Here, since the service server 30 can know the actual content of the terminal authentication token Token_B, the service server 30 can obtain the third random number R3 from the terminal authentication token Token_B. Also, the service server 30 may decrypt the session key (Key_B) using the second shared key (Key_C).

Subsequently, the service server 30 generates a second session key (Key_D) using the third random number R3 thus obtained and the session key (Key_B) received from the authentication server 20 (step S323).

The service server 30 decrypts the verification information S with the generated second session key (Key_D) (step S324).

Then, the service server 30 encrypts the data with the generated second session key (Key_D) and transmits the encrypted data to the terminal 10 (step S325). At this time, the service server 30 may calculate the information S-1 calculated from the decrypted information, encrypt the information S-1 with the second session key Key_D, and transmit the information S-1 together with the data.

The terminal 10 decrypts the information S-1 calculated by the second session key (Key_D) to verify the presence or absence of the previously transmitted verification information, and performs verification of the service server 30 (step S326). At the same time, the terminal 10 can decrypt the data with the second session key (Key_D) to confirm the data.

In this way, even when the authentication server is configured separately from the service server, bidirectional authentication between the terminal 10 and the authentication server 20 and verification between the terminal 10 and the service server 30 can be performed quickly and stably Can be performed.

Such methods may be implemented by a two-way authentication system as shown in FIGS. 1 and 3, and in particular as a software program that performs these steps, in which case these programs may be stored in a computer- Transmitted by a computer data signal stored in a medium or coupled to a carrier wave in a transmission medium or a communication network.

At this time, the computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. For example, ROM, RAM, CD-ROM, DVD-ROM, DVD- , A floppy disk, a hard disk, an optical data storage device, and the like.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

10: terminal 20: server, authentication server
30: service server

Claims (14)

Encrypting the server authentication token generated by the terminal with its own secret key using the dynamic key generated by the shared key, and transmitting the encrypted token to the server to request the service;
The server decrypts the server authentication token received from the terminal with the dynamic key generated by the shared key and then encrypts the shared key and the session key generated by the dynamic key using the secret key of the server itself Encrypting the generated terminal authentication token with the generated dynamic key, and transmitting the authentication result to the terminal together with the server authentication token encrypted with the session key to request server authentication;
Decrypting the server authentication token received from the server with the shared key and the session key generated using the dynamic key, and then decrypting the decrypted server key with the secret key of the terminal to authenticate the server;
Decrypting the terminal authentication token received from the server with the dynamic key, encrypting the terminal with the generated session key, and transmitting the encrypted session key to the server to request terminal authentication; And
And decrypting the terminal authentication token received from the terminal with the dynamic key and decrypting the decrypted token with the secret key of the server using the dynamic key to authenticate the terminal. The method according to claim 1,
Wherein the dynamic key is a dynamic key generation algorithm shared between the server and the terminal and a symmetric key based security token generated by a shared key. The method according to claim 1,
Wherein the step of requesting the service and the step of requesting the terminal authentication are performed by encrypting a random number different from each other with the dynamic key and transmitting the same. The method of claim 3,
Wherein the session key is generated by using a different random number than the symmetric key based security token. The method according to claim 1,
Transmitting an ID of the terminal when the service is requested;
Encrypting the ID of the terminal with the dynamic key and transmitting the encrypted ID; And
And authenticating the server by decrypting the ID of the encrypted terminal by using the secret key. The method according to claim 1,
Wherein the shared key is an authentication supplicant security key (ARSK), which is a symmetric key based security token. The method according to claim 6,
Wherein the authentication requestor security key (ARSK) is stored and shared in the server and the terminal when the terminal is an Internet Internet (IoT) device. The method according to claim 6,
Wherein the authentication requestor security key (ARSK) is stored only in the server and is not stored in the terminal, when the terminal is a user terminal, and is input when generating the dynamic key using a knowledge base, using the symmetric key based security token. 9. The method of claim 8,
Wherein the authentication requestor security key (ARSK) is a symmetric key based security token comprising at least one of a password and a fingerprint. The method according to claim 1,
Wherein the server includes a service server and an authentication server,
Wherein the steps are performed between the authentication server and the terminal,
Wherein the terminal authentication token is generated by being encrypted with a second shared key shared between the authentication server and the service server,
Encrypting the decrypted terminal authentication token with the generated session key, and transmitting the decrypted terminal authentication token to the service server to request a connection; And
And decrypting the terminal authentication token received from the terminal with the session key received from the authentication server and then decrypting the decrypted terminal with the second shared key to authenticate the terminal, Way authentication method using. 11. The method of claim 10,
The service server requesting the session key from the authentication server; And
And the authentication server encrypts the session key with the second shared key and transmits the encrypted session key to the service server. 11. The method of claim 10,
Transmitting verification information encrypted with a second session key generated by a third random number included in the session key and the terminal authentication token to the service server when the connection request is made;
The service server obtaining the third random number from the decrypted terminal authentication token, generating the second session key with the session key and the third random number, and decrypting the verification information with the second session key ;
Encrypting information calculated from the decrypted verification information with the second session key and transmitting the encrypted information to the terminal; And
And decrypting the calculated information by the terminal with the second session key to identify the service server. ≪ RTI ID = 0.0 > [10] < / RTI > Encrypting the server authentication token generated by encrypting with the secret key using the dynamic key generated by the shared key, and transmitting the encrypted token to the server to request the service;
Receiving the server authentication token encrypted with the session key from the server according to the request, generating the session key using the shared key and the generated dynamic key, and transmitting the received server authentication token to the generated session Authenticating the server by decrypting the decrypted data using the secret key; And
Receiving the encrypted terminal authentication token from the server, decrypting the encrypted terminal authentication token with the dynamic key, encrypting the encrypted with the session key, and transmitting the encrypted terminal authentication token to the server so that the server authenticates the terminal A two - way authentication method using a symmetric key - based security token. The server authentication token received in response to the service request from the terminal is decrypted with the dynamic key generated by the shared key and then encrypted using the shared key and the session key generated by the dynamic key, Encrypting the token with the generated dynamic key, and transmitting the encrypted token to the terminal together with the server authentication token encrypted with the session key to request server authentication; And
Receiving a terminal authentication token encrypted with the session key according to a terminal authentication request after server authentication in the terminal, decrypting the terminal authentication token using the generated dynamic key, and decrypting the decrypted terminal with the secret key to authenticate the terminal; Way authentication method using security token.

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