KR20070062199A - Method for authenticating user using id/password - Google Patents

Abstract

A method for authenticating a user with an ID and a password is provided to authenticate a server and authenticate a client user after the server is authenticated in a home network environment by using a certificate of the server, and enable a client to authenticate the user by using the ID/password without using the certificate while using the certificate of the user for user authentication between the client and the server. The client transmits a message including information indicating the user authentication uses the ID/password to the server. The client receives and verifies the certificate of the server. If the received certificate is verified, a password key used in the server is generated and shared through key generation/exchange. The client authenticates the user by calculating a hash value for copied user authentication data corresponding to original user authentication data and encoding the hash value with the password key.

Description

Method for authenticating user using ID / password}

1 is a flowchart illustrating a user authentication method between a client and a server using a conventional EAP-MD5;

2 is a block diagram illustrating a home network system to which an embodiment of the present invention is applied;

3 is a flowchart illustrating a user authentication method using an ID / password between a client and a server according to an embodiment of the present invention;

4 is an example of a packet format at the time of server authentication in FIG.

5 is an example of a packet format for user authentication in FIG. 3, and

6 is an example of a flag form in FIG. 4 or FIG. 5.

The present invention relates to a user authentication method using ID / password, and more particularly, only a user whose ID / password information is pre-registered on a home server in a home network system can use the home network system, and client user authentication The present invention relates to a user authentication method and system for providing an authentication means using ID / password information to protect a user's privacy and provide safety and convenience.

In relation to the user authentication method, Extensible Authentication Protocol (EAP), which is designed to accommodate various authentication methods in PPP (The Point-to-Point Protocol), is widely used, which has the advantage of being applicable to any link layer. EAP is used to transfer authentication information between the authentication requester and the server. The basic operation consists of repetition of request and response, and the authentication process differs slightly depending on the EAP authentication type.

In the conventional authentication method using ID / PW information, security vulnerabilities have been found, but EAP-MD5 has been widely used because it is easy to use. In EAP-MD5, bi-directional authentication is not one-way authentication, but the server authenticates the user of the client, but the client passes authentication information without authenticating the server.

In addition, the authentication process is performed by comparing the user ID information of the challenge-response method with the response to the challenge, not the authentication method by generating any key. However, it is quite vulnerable to an offline dictionary attack, and the protocol is fully exposed to man-in-the-middle-attack (MITM) and denial of service (DoS), which poses a security problem. That is, since user ID information, challenge, and response are transmitted in the form of plain text without using a key, it is possible to leak ID / password from many pairs of user ID information, challenge, and response through packet capture, etc. During the authentication protocol handshake, an attacker can intervene to alter the packet or stop receiving the service.

Therefore, there are authentication techniques that complement the security weaknesses of conventional authentication mechanisms such as EAP-MD5, enable two-way authentication, form an encrypted channel, and protect the conventional authentication mechanism through the channel. However, these techniques have a complicated packet configuration because the channel formation process and the requestor authentication process are separated to further include an internal EAP packet including a TLS packet in an external EAP packet that forms a secure channel. This can be an overhead in the process. This is a general authentication mechanism that does not consider the home network environment. It is necessary to reduce the weight according to the performance of the home gateway or the home gateway or home server that performs the authentication mechanism in the home network.

In addition, secret key exchange is a very important factor in the process of creating a secure channel, and there is a technique for explaining the authentication method assuming that the secret key has been previously distributed. This authentication method raises the question of how to exchange the secret key before the authentication process. And, if the authentication method using the conventional secure channel is an authentication method that does not generate a key, such as EAP-MD5, if the authentication method used in the secure channel is protected, even if the user ID information is protected, the key and internal authentication method generated when the secure channel is formed There is still no vulnerability for MITM attacks.

1 is a flowchart illustrating a user authentication method between a client and a server using a conventional EAP-MD5. Referring to FIG. 1, when the client 10 transmits an EAP-Start message, which is a user authentication request start message requesting to start user authentication, to the server 20 (S10), the server 20 receiving the EAP-Start message. In response to this, the EAP-Request / Identity message, which is a user identity information request message, is transmitted (S11).

The EAP-Request / Identity message is a message that the server asks for the identity of the client 10, and the client 10 receiving such a message responds with an EAP-Response / Identity message, which is a user identity information response message (S12). . The EAP-Response / Identity message includes location information and identity information for the identity of the client 10, and includes information that EAP-MD5 is used as an authentication method. Upon receiving the EAP-Response / Identity message, the server 20 transmits an EAP-Request / Challenge message, which is a hash value request message including a random value (S13). The EAP-Request / Challenge message contains a challenge, which is a random number required for the authentication requestor's authentication, and the client 10 receiving the message calculates the challenge received from the server 20 and its ID and password through the MD5 algorithm. It responds with an EAP-Response / Response message, which is a hash value response message containing one hash value (S14). Upon receiving the EAP-Response / Response message, the server 20 checks the hash value received from the client 10 and the hash value calculated by the server 10 and transmits an EAP-Success message, which is a user authentication success message, when authentication is successful. (S15).

In the case of FIG. 1, since the client 10 is a one-way authentication in which the client user's authentication information is transmitted to the server 20 without being authenticated by the server 20, the client 10 may perform a normal authentication process. If you receive an EAP-Fail message instead of an EAP-Success message, you can no longer access the server 20, and there is no secret key exchange during the user authentication process. There is a security problem that must be protected through key exchange.

The present invention for solving the problems of the prior art provides a method for authenticating a server first through a certificate of the server in a network environment, particularly a home network environment, and then authenticating a client user after the server is authenticated.

In addition, only the certificate of the server is required for user authentication between the client and the server, and the client provides a method of authenticating a user using ID / password information without requiring a certificate.

In addition, the secret key to be used by the client and server is generated and exchanged during the server authentication process, and the secret key provides a method used to protect user authentication information during the client user authentication process.

In addition, the algorithm used in the client user authentication process uses a hash function such as HMAC-MD5 or HMAC-SHA that requires the use of a key, and the key used is regenerated from the secret key generated and exchanged during authentication server authentication. It is used in authentication mechanisms to provide security against MITM attacks.

In the user authentication method using the ID / password of the present invention for solving the technical problem, in the method for performing user authentication by accessing the user authentication original data including the ID / password from the client to the server that is stored in advance (a) transmitting, by the client, a message including information indicating that the client uses an ID / password method for user authentication; (b) receiving and verifying a certificate of the server from the server; (c) generating and sharing a secret key for use with the server through key generation and exchange when the received certificate is verified; And (d) performing a user authentication by calculating a hash value of the user authentication comparison data corresponding to the user authentication original data, encrypting the data with the secret key, and transmitting the encrypted data to the server.

In addition, the user authentication method using the ID / password of the present invention for solving the above technical problem, in a method for authenticating a client user to connect to the server from a server that previously stored the user authentication original data, (a Receiving a message including information indicating that an ID / password method is used from the client; (b) sending the server's certificate to the client; (c) receiving and sharing a secret key generated when the server's certificate is verified by the client with the client; (d) receiving a hash value for the user authentication comparison data corresponding to the user authentication original data encrypted with the secret key from the client; And (e) comparing the hash value with respect to the user authentication comparison data and comparing the hash value with respect to the original user authentication data to authenticate the client user.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram illustrating a home network system to which a preferred embodiment of the present invention is applied.

2, a home network system to which a preferred embodiment of the present invention is applied includes a home server 100, an indoor client 110, an indoor device 120, a home network operator server 130, and an outdoor client 140. And user authentication means 112,142. Here, all devices are connected to the home server 100.

The home server 100 is responsible for device authentication and user authentication, home device control and home service.

The indoor client 110 requests the control of the indoor device 120 or the home service in the home, or uses the service provided by the home network operator server 130.

The indoor device 120 is a device configuring a home network system in the home.

The home network operator server 130 authenticates the home server 100, authenticates the user with the indoor client 110 or the outdoor client 130, and provides various services.

The outdoor client 140 requests the home device 120 control and the home service from the outside through the home server 100 or uses the service provided by the home network operator server 130.

Before describing the home network system authentication method, the indoor devices 120 and the indoor client 110 should be registered in the home server 100. In addition, when registering a user, the user ID / password information to be used for authentication should be stored in the home server (100).

The indoor devices 120 are connected to the home server 100, and the home server 100 is connected to the home network operator server 130.

3 is a flowchart illustrating a user authentication method using ID / password between a client and a server according to an exemplary embodiment of the present invention.

The EEAP-PW protocol used in the user authentication method and apparatus of FIG. 3 consists of a request and a response. The server sends a request for access to the system and grants or denies access based on the response to the request.

It also provides mutual authentication, authenticates the server first using the server's certificate, then exchanges the secret key to be used between the server and the client, and regenerates the key needed in the user's authentication process from the exchanged secret key to authenticate the user. You can authenticate the client user more securely by using it in the process and encrypting the entire client user authentication process using the exchanged secret key.

Referring to FIG. 3, first, the client 310 transmits an EAP-Start message, which is a user authentication request start message, to the server 300 (S300).

Next, the server 300 receiving the EAP-Start message in step S300 transmits an EAP-Request / Identity message, which is a user identity information request message, to the client 310 in response (S301). The EAP-Request / Identity message requests information about the ID information, location information (domain information), authentication method information to be used, etc. of the client 310 user.

Next, the client 310 receiving the EAP-Request / Identity message in step S301 transmits an EAP-Response / Identity message, which is a user identity information response message, to the server 300 (S302). Here, the EAP-Response / Identity message includes only the location information on the identity of the client user and the information that the EEAP-PW is used as an authentication method. That is, the user's ID information is not included.

Next, the server 300 receiving the EAP-Response / Identity message in step S302, the EAP-Request / EEAP-PW (Start), which is an EEAP-PW authentication start message including information indicating that the EEAP-PW is used as a user authentication method. ) Transmits the message to the client 310 (S303).

Next, the client 310 receiving the EAP-Request / EEAP-PW (Start) message in step S303 is an EAP-Response / EEAP-PW (ClientHello) message which is a client hello message as a TLS communication start message with the server 300. To transmit to the server 300 (S304). Here, the contents that may be included in the EAP-Response / EEAP-PW (ClientHello) message include the TLS version of the client 310, the random number generated by the client 310, the session identifier, the CipherSuit list, and the compression method of the client 310. It can contain a list.

Next, in step S304, the server 300 receiving the EAP-Response / EEAP-PW (ClientHello) message includes an EAP-Request / EEAP-PW (ServerHello, Server Hello Server Certificate, Server Key Exchange, and Server Hello End). ServerCertificate, ServerKeyExchange *, ServerHelloDone) message is transmitted (S305).

In this case, the ServerHello message includes one CipherSuit selected from a TLS version of the server 300, an arbitrary random number generated by the server 300, a session identifier, and a CipherSuit list transmitted by the client 310 in step S304, and the client in step S304. A compression method selected from the compression method list transmitted by the 310, and the like. ServerCertificate contains a server certificate, and ServerHelloDone indicates that a ServerHello message has ended.

The ServerKeyExchange message is determined according to the type of certificate. In other words, there is a certificate for the server 300 for signing (Sign ature i) may further include a server key exchange message (ServerKeyExchange) containing a public key of the server 300 in the case of certificates.

Next, in step S305, the client 300 receiving the EAP-Request / EEAP-PW (ServerHello, ServerCertificate, ServerKeyExchange *, ServerHelloDone) message authenticates the server 300 through the server certificate, and if the client is authenticated, EAP-Response / EEAP-PW (ClientKeyExchange, ChangeCipherSpec, Finished) message, which includes key information of 310, key exchange algorithm, cryptographic algorithm, integrity algorithm, etc. and indicates that the negotiation with the server 300 was successful. Is transmitted to the server 300 (S306). Here, the authentication method of the server 300 through the server certificate is made through a conventionally known certificate authentication method.

Next, the server 300 receiving the EAP-Response / EEAP-PW (ClientKeyExchange, ChangeCipherSpec, Finished) message in step S306 includes a key exchange algorithm, an encryption algorithm, an integrity algorithm, and the like, and the negotiation with the client 310 is successful. The EAP-Request / EEAP-PW (ChangeCipherSpec, Finished) message indicating that the transmission is made is transmitted to the client 310 (S307).

From step S300 to step S307 is to authenticate the server 300 through the server certificate in the client 310, the subsequent process is the client 310 user through the ID and password information of the client 310 user in the server 300 To authenticate.

Next, in step S307, the client 310 receiving the EAP-Request / EEAP-PW (ChangeCipherSpec, Finished) message generates and exchanges ID information, which is user's identity information, during the certificate verification process of the server 300. The EAP-Response / EEAP-PW (UserID) message, which is a user ID information message encrypted with a key, is transmitted to the server 300 (S308).

Next, the server 300 receiving the EAP-Response / EEAP-PW (UserID) message in step S308 includes a challenge, which is a random value required for authenticating the client 310, and during the authentication process of the server 300. The EAP-Request / EEAP-PW (Challenge) message, which is a hash value request message encrypted with the generated and exchanged secret key, is transmitted to the client 310 (S309).

Next, the client 310 receiving the EAP-Request / EEAP-PW (Challenge) message in step S309 uses the challenge, user ID, and password information received in step S309 as a key such as HMAC-MD5 or HMAC-SHA. The EAP-Response / EEAP-PW (Response) message, which is a hash value response message including the hash value calculated through the hash algorithm used, is transmitted to the server 300 (S310). Here, the EAP-Response / EEAP-PW (Response) message, which is a hash value response message, is encrypted with a secret key generated and exchanged during the authentication process of the server 300 and transmitted to the server 300. In addition, the key necessary for generating the hash value is regenerated from the secret key generated and exchanged during the server authentication process.

Next, the server 300 receiving the EAP-Response / EEAP-PW (Response) message in step S310 compares the hash value received from the client 310 with the hash value calculated by the client 310 and matches the client 310. The EAP-Success message, which is a user authentication success message, is transmitted to the client 310 (S311). Here, the key necessary for the server to calculate the hash value is regenerated from the secret key generated and exchanged during the server authentication process.

To summarize the above process, first for the mutual authentication between the client 310 and the server 300, first authenticate the server 300 through a server certificate, the client 310 user with the generated and exchanged secret key To protect the authentication mechanism. In addition, the authentication mechanism of the user of the client 310 uses a hash algorithm using a key, and the key used at this time is regenerated from a secret key shared during server authentication. Therefore, by encrypting and transmitting not only the user's ID information but the entire user authentication process, the vulnerability such as MITM attack can be solved.

In FIG. 3, the server 300 and the client 310 have been described. As a technical field to which the present invention can be applied, the present invention can be applied to the home network system described in FIG. 2 as follows.

When using a home network system in the home, the client 310 becomes a home client and the server 300 becomes a home server. And, depending on the application, the client 310 may be a home server and the server 300 may be a home network operator server, the client 310 may be a home client, and the server 300 may be a home network operator server. It may be.

In addition, in the case of using a home network system outside the home, the client 310 becomes an outdoor client and the server 300 becomes a home network operator server.

4 is an example of a packet format in server authentication in FIG. 3. 4 illustrates a packet structure used in a process in which a client user authenticates a server through a server certificate according to the present invention.

Referring to FIG. 4, when the client 300 authenticates the server through the server certificate, the header part of the packet structure includes a code, identifier, length, and type fields. The part consists of flags, TLS message length, and TLS data.

The code field is a field indicating request and response, and it is represented as '1' in case of request and '2' in case of response.

The identifier field changes in each request packet, and the identifier field of the response must be equal to the value of the corresponding request packet.

The length field consists of 2 bytes and represents the length of the entire packet from the code field to the data portion.

The type field value represents the EEAP-PW and uses a temporary value of '80', which can be changed in the formal standard.

The flag field is used to display information of the data portion, which uses one byte, and uses seven bits, and does not use the remaining one bit. 6 shows the configuration of a flag field.

FIG. 5 is an example of a packet format for user authentication in FIG. 3. 5 illustrates a packet structure used in a process in which a server authenticates a client user according to the present invention.

Referring to FIG. 5, the packet structure at the time of user authentication has the same packet structure and the header portion at the time of server authentication, and the flag field of the data portion is equally applied. However, the packet structure following the flag field varies according to the bit value of the flag field. That is, if the 'U' bit indicating whether the current authentication process is a server authentication process or a user authentication process is 0, the current authentication process is a server authentication process and the packet structure has a TLS packet structure. However, if the 'U' bit is '1', it indicates that the server authentication process is successfully completed and the user authentication process. Therefore, it consists of Encrypted-PW packet consisting of a 2-byte value-size field and a value field. .

6 is an example of a flag form in FIG. 4 or FIG. 5. Referring to FIG. 6, in the configuration of the flag field, the first 'L' bit is designated when the TLS message length field is present and is set to '1' only for the first fragment of the fragment. The second 'M' bit indicates the presence or absence of one or more messages, which is set to '1' for all fragments except the last fragment. And, the third 'S' bit indicates the start message of EEAP-PW. It is set to '1' at the first start and '0' thereafter. The fourth 'U' bit indicates that the current packet structure is Encrypted-PW packet structure. It is set to '0' in server authentication process and '1' in user authentication process after server authentication is completed successfully. Finally, the sixth through eighth bits are the 'V' bits that represent the version information of the EEAP-PW.

The flag form described with reference to FIG. 6 has been described as an example, and various modifications may be made.

The invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD_ROM, magnetic tape, floppy disks, and optical data storage, and also include those implemented in the form of carrier waves (eg, transmission over the Internet). . The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

As described above, optimal embodiments have been disclosed in the drawings and the specification. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not intended to limit the scope of the present invention as defined in the claims or the claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

The user authentication method using the ID / password of the present invention described above has the following effects.

First, the user authentication method proposed in the present invention authenticates the server with the server's certificate, thereby providing user safety and convenience by securely mutually authenticating only the user's ID / password without requiring a separate certificate.

Secondly, in the user authentication method proposed in the present invention, the user of the client can trust the server and transmit user authentication information by authenticating the user after the server authentication process, such as server authentication and client user authentication.

Third, in the user authentication method proposed in the present invention, after authenticating the server with the server's certificate, the secret key is shared between the client and the server, thereby protecting the user's ID information, as well as the key used in the client's user authentication process. Since it is regenerated from the secret key generated during the authentication process of the server, security threats can be solved from the spoofed authentication server or the spoofed authentication client, and the damages from attacks such as MITM can be prevented.

Fourth, the user authentication method proposed in the present invention is configured by differently configuring the packet configuration used in the server authentication and client user authentication process, thereby reducing the overhead of the authentication process by reducing the packet configuration of the client user authentication process It is compatible with the conventional user authentication method. Therefore, it is possible to interwork and compatible with the user terminal, AP, AAA server and the like in the WLAN.

Fifth, the user authentication method and apparatus proposed by the present invention are most suitable for home network environments, but can be variously used in other network environments. In addition, the present invention can be used regardless of the network structure and communication media (eg, WLAN, Ethernet, etc.).

Claims (21)

A method of authenticating a user by accessing user authentication source data including ID / password from a client to a pre-stored server, (a) transmitting, by the client, a message including information indicating that the user uses an ID / password method for user authentication; (b) receiving and verifying a certificate of the server from the server; (c) generating and sharing a secret key for use with the server through key generation and exchange when the received certificate is verified; And (d) calculating a hash value of the user authentication comparison data corresponding to the user authentication original data, encrypting with the secret key, and transmitting the encrypted data to the server to perform user authentication; User authentication method using. The method according to claim 1, wherein before step (a) The client sending an authentication service access message to the server; And Receiving a user identity information request message of the client from the server; User authentication method using the ID / password further comprising. The method of claim 1, wherein step (d) (d1) the client receiving a user authentication comparison data request message from the server; (d2) encrypting the user authentication comparison data with the secret key and transmitting the encrypted data to the server; And (d3) receiving a user authentication success message generated when it is determined that the server compares the user authentication comparison data transmitted in the step (d2) with the user authentication original data previously registered in the server and matches the data; User authentication method using an ID / password characterized in that consisting of. The method of claim 3, wherein before step (d1) And encrypting a user ID with the secret key and transmitting the encrypted user ID to the server. The method of claim 1, The ID / password method is a user authentication method using an ID / password, characterized in that the EEAP-PW method. The method of claim 1, The client and server are applied to the home network system, And the client is a home client of the home network system, and the server is a home server of the home network system. The method of claim 1, The client and server are applied to the home network system, And the client is a home server of the home network system, and the server is a home network operator server of the home network system. The method of claim 1, The client and server are applied to the home network system, And the client is an outdoor client of the home network system, and the server is a home network operator server of the home network system. The method of claim 1, ID / password, characterized in that the configuration of the packet used in the verification of the server certificate of the step (b) and the client user authentication of the step (d) is used differently according to the bit value of the flag field of the packet. User authentication method. The method of claim 9, And a TLS type packet and an Encrypted-PW type packet according to the U bit value of the flag field. The method of claim 1, And a key necessary for calculating a hash value of the comparison data of the user authentication is regenerated from the secret key and used. In the method for authenticating a client user who wants to access the server from a server that previously stored user authentication original data, (a) receiving a message including information indicating that an ID / password scheme is used from the client; (b) sending the server's certificate to the client; (c) receiving and sharing a secret key generated when the server's certificate is verified by the client with the client; (d) receiving a hash value for the user authentication comparison data corresponding to the user authentication original data encrypted with the secret key from the client; And (e) comparing the hash value with respect to the user authentication comparison data and comparing the hash value with respect to the original user authentication data, and authenticating the client user. Way. The method of claim 12, wherein before step (a) Receiving an authentication service access message from the client; And And transmitting the identity information request message of the client user to the client. The method of claim 12, wherein step (d) (d1) receiving user ID information from the client; (d2) transmitting a corresponding user authentication comparison data request message to the client; And (d3) The user authentication method using the ID / password characterized in that the step of receiving a hash value to the user authentication comparison data encrypted with the secret key from the client. The method of claim 12, The ID / password method is a user authentication method using an ID / password, characterized in that the EEAP-PW method. The method of claim 12, The client and server are applied to the home network system, And the client is a home client of the home network system and the server is a home server of the home network system. The method of claim 12, The client and server are applied to the home network system, And the client is a home server of the home network system and the server is a home network operator server of the home network system. The method of claim 12, The client and server are applied to the home network system, And the client is an outdoor client of the home network system and the server is a home network operator server of the home network system. The method of claim 12, User authentication method using ID / password, characterized in that for verifying the server certificate of step (b) and the configuration of the packet used in the client user authentication differently according to the bit value of the flag field of the packet. The method of claim 19, And a TLS type packet and an Encrypted-PW type packet according to the U bit value of the flag field. The method of claim 12, And a key necessary for calculating a hash value of the comparison data of the user authentication is regenerated from the secret key and used.

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