KR20090031706A - System and method for secure communication, and a medium having computer readable program executing the method - Google Patents

Abstract

A system and method for secure a communication, and a medium is provided to secure the network security of a HTTP(Hypertext Transfer Protocol) when a session key information is disclosed. A secure communication system(100) includes an discrimination information extraction unit(110) and response message sending unit(120). The discrimination information extraction unit extracts discrimination information from a transmitted message from a web browser. If the discrimination information satisfies a certain condition, the response message sending unit transmits a response message to the web browser. The discrimination information extraction unit includes an encryption value extracting unit and a decoder, which decodes the extracted encryption value.

Description

A system and method for secure communication, and a medium having computer readable program executing the method}

The present invention relates to a secure communication method, and more particularly to a secure communication method in HTTP communication.

HTTP (hypertext transfer protocol) refers to a communication protocol used for transferring a document between a web server and a user's Internet browser on the Internet, and is a communication protocol used for exchanging hypertext documents on the Internet.

Hypertext refers to a method of placing a specific keyword in the middle of a document and combining characters or pictures in an organic manner so that they can be referred to as one document even though they are different characters.

1 is a schematic diagram illustrating a general flow of data in HTTP.

In general, when an Internet user visits a web site, a process of 1 to 4 is repeated several times.

In FIG. 1, both a request and a response are composed of a header and a body. The header of the request includes a request service, additional information, and additional information related to a body. The body includes data input on the web. The body may not be present.

The response header includes a response code, body information, additional information, and information for requesting a specific action from the web browser, and the body is composed of data to be expressed in the web browser.

Since HTTP itself does not provide a session function, a virtual session function is implemented by using a cookie. Cookies are information stored in a web browser and are additional information added to the header part when a request is sent.

2 is a schematic diagram illustrating a configuration in which a web browser and a web server communicate using cookies.

In FIG. 2, the web server adds specific information to the header portion of the response to allow the web browser to manage cookies. The web server receives and processes requests from several browsers at the same time, and implements a session function separately to distinguish each browser. Currently, the most commonly used session functionality is implemented using cookies and storage on the server.

When a web browser connects to or logs in to a web server, the web server issues a session key to the additional information "Set-Cookie:" in the header of the response. The web browser stores the session key in the browser by the Set-Cookie header received from the web server. After that, the web browser adds the session key to the header "Cookie:" and sends the request.

The web server extracts the session key from the cookie portion of the web browser's request and finds the session information in the session table. The web server may store various information such as login information and user information in the session.

A session is information stored in a web server, and the web browser has a session key corresponding to the session. The web browser embeds the session key in a specific part of the request (usually a cookie), allowing the web server to find the session.

However, the problem is that if the session key information of the request is leaked and stolen, it is difficult for the web server to detect the theft of the corresponding session key. This is because the web server sends a response using the existing session information even when the key for the already established session is copied and used in another web browser.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a communication system and method for maintaining the security of HTTP communication even when the session key information is leaked.

In order to achieve the above object, the secure communication system according to the first aspect of the present invention includes an identification information extracting unit and a response message transmitting unit. The identification information extracting unit extracts identification information of the request message from the request message transmitted from the web browser, and the response message transmitting unit transmits a response message corresponding to the request message to the web browser when the web browser identification information satisfies predetermined identification criteria. do.

Since the response message is transmitted only to the web browser which transmits the identification information satisfying the predetermined identification criteria among the connected web browsers, the security of the HTTP communication can be maintained even when the session key information is leaked.

The identification information extractor may include an encryption value extractor that extracts an encryption value of the identification information from the request message, and a decryption unit that decrypts the extracted encryption value. In this way, by encrypting and transmitting the identification information, misuse of the identification information can be prevented.

Decryption may be performed using an encryption key transmitted from a web browser, and the encryption key may be encrypted with a public key of a web server. This configuration makes it possible to more securely secure the communication between the web browser and the web server.

The secure communication system may further include a program transmitter for transmitting a computer program including identification information in a request message of the web browser to a communication terminal on which the web browser is executed. This configuration makes it easier for users without communication expertise to use secure communications.

In addition, the secure communication system may further include a request message body decryption unit for decrypting the encrypted body content of the request message sent from the web browser, or the response message body encryption for encrypting the body content of the response message sent to the web browser It may further include wealth. This configuration enables the security of the body content of the request message and the response message respectively transmitted between the web browser and the web server.

In addition, the security communication system according to the second aspect of the present invention includes an identification information generation unit and an identification information insertion unit. The identification information generation unit generates identification information of the request message when the web browser accesses the web server, and the identification information insertion unit inserts the identification information in the request message transmitted by the web browser to the web server.

By transmitting the identification information of the web browser to the connected web server, the web server sends a response message only to the web browser of the identification information that satisfies the preset criteria. Therefore, even if the session key information is leaked, the security of the HTTP communication can be maintained. Will be.

In addition, an invention in which the system is implemented in the form of a method, and a computer readable recording medium for executing the method are disclosed.

The present invention ensures the validity and uniqueness of the data exchanged on the session established between the web server and the web browser.

In addition, even if the session information is leaked, it is impossible to intercept or interrupt the session because the encryption key value and the session number are not known.

In addition, it denies retry requests using already-used requests and enhances the security of communication between the server and the client by not allowing any requests to be made arbitrarily.

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

3 is a schematic block diagram illustrating the use state of one embodiment of a secure communication system according to the present invention.

In FIG. 3, the web server 100 and the web browser 300 may perform secure communication via the relay program 200.

The relay program 200 is a program that inserts or verifies necessary information located in the middle of the communication between the web browser and the web server, and is added to the web browser of the user terminal, or an independent program separate from the web browser. It may be implemented in the form.

The relay program 200 may be immediately inserted without developing additional programs to intervene in communication between the browser and the server.

The relay program 200 may insert the authentication information into the request of the browser and transmit the authentication information to the server, process the verification and analysis of the response from the server, and then retransmit it to the browser.

In addition, it is possible to add the encryption processing of the body to the request of the browser and the decryption processing to the response of the server.

4 is a schematic block diagram illustrating an embodiment of one aspect of a secure communication system in accordance with the present invention.

The secure communication system 100 of FIG. 4 may be implemented as a web server, and includes an identification information extracting unit 110, a response message transmitting unit 120, a program transmitting unit 130, a request message body decrypting unit 140, and The response message body encryption unit 150 is included, and the identification information extraction unit 110 further includes an encryption value extraction unit 112 and a decryption unit 114.

The identification information extracting unit 110 extracts identification information of the request message from the request message transmitted from the web browser.

At this time, the encryption value extraction unit 112 extracts an encryption value of the identification information from the request message. In this way, by encrypting and transmitting the identification information, misuse of the identification information can be prevented.

The decryption unit 114 decrypts the extracted encryption value. Decryption is performed using an encryption key sent from a web browser. In this case, the encryption key may be encrypted with the public key of the web server. This configuration makes it possible to more securely secure the communication between the web browser and the web server.

The response message transmitter 120 transmits a response message corresponding to the request message to the web browser when the web browser identification information satisfies a predetermined identification criterion.

The predetermined identification criteria may be transmitted in advance from the web browser on a preset basis between the system 100 and the web browser.

Since the response message is transmitted only to the web browser which transmits the identification information satisfying the predetermined identification criteria among the connected web browsers, the security of the HTTP communication can be maintained even when the session key information is leaked.

The present invention presents the concept of one time request (OTR). OTR refers to a function that prevents reuse of the information once used, and comprehensively refers to a function that the web server does not process even if the browser makes a request again for a request made by the server.

Therefore, according to the present invention, even when the same request message is repeatedly transmitted from the same web browser, the response message may not be repeatedly transmitted.

The program transmitter 130 transmits the computer program including the identification information in the request message of the web browser to the communication terminal running the web browser. This configuration makes it easier for users without communication expertise to use secure communications.

The request message body decryption unit 140 decrypts the encrypted body content of the request message transmitted from the web browser, and the response message body encryption unit 150 encrypts the body content of the response message transmitted to the web browser.

The basic communication protocol of the web is HTTP, which is vulnerable to security because the protocol lacks encryption / decryption. In order to compensate for this, the HTTPS (Secure) protocol has been enacted, thereby enhancing security. In other words, the security feature added to HTTP is HTTPS.

 To use HTTPS, you need to get a certificate from the server certificate issuer and install it on the web server. In this case, since a unit issuance fee is incurred every year, a small shop operating a general web server is not actually introduced due to the burden of installing and managing a server certificate.

When the encryption function of the relay program is used as in the present invention, the security can be handled at the HTTPS level even under HTTP. This allows security levels to achieve HTTPS levels, despite less installation burden.

In addition, the authentication period is conventionally limited by a year, and the security level can only use the security level specified in the server certificate. However, when the relay program of the present invention is used, a higher security level can be immediately applied as necessary. It becomes possible. In addition, the authentication period can also be arbitrarily adjusted.

In case of HTTPS, the authentication of the user is insufficient because the focus is on the authentication of the web server and the security of data exchanged with each other, rather than the confirmation of the user. In other words, existing HTTPS is one-way authentication.

However, in the relay program of the present invention, it is possible to increase the security level by enabling two-way authentication by adding a user authentication process using a user's authorized certificate.

5 is a schematic block diagram illustrating an embodiment of another aspect of a secure communication system in accordance with the present invention.

In FIG. 5, the secure communication system 200 may be implemented as a relay program, and includes an identification information generation unit 210, an identification information insertion unit 220, an encryption key transmission unit 230, and a request message body encryption unit 240. And a response message body decoder 250.

The identification information generating unit 210 generates identification information of the web browser when the web browser accesses the web server, and the identification information inserting unit 220 inserts the identification information in the request message transmitted by the web browser to the web server. . At this time, the identification information is encrypted and inserted.

By transmitting the identification information of the web browser to the connected web server, the web server sends a response message only to the web browser of the identification information that satisfies the preset criteria. Therefore, even if the session key information is leaked, the security of the HTTP communication can be maintained. Will be.

The encryption key transmitter 230 transmits an encryption key for decrypting the encrypted identification information to the web server. At this time, the encryption key is encrypted with the public key of the web server.

The security system 200 may be implemented as a computer program, which may be transmitted from a web server.

The request message body encryption unit 240 encrypts the body content of the request message transmitted to the web server, and the response message body decryption unit 250 decrypts the encrypted body content of the response message transmitted from the web server.

Other methods may be considered as a method for preventing the security risk of communication due to the leakage of session key information.

The first is to prevent the leakage of session key information. This method works for most security-enhanced sites. It may be difficult to find a session key using a hidden cookie, or to make it difficult to leak session information from an e-mail, a post, a blog, or the like.

However, the method of making the leak of session key information difficult is not a fundamental solution to the problem. This is because it is not a method to disable the leakage of session key information.

A second approach might be to store the IP of the computer running the web browser in the session and check whether the computer requesting the request is the same computer.

However, there are a number of vulnerabilities and constraints in how IP is scanned. In an environment where IP is dynamically changed by using NAT equipment such as a large enterprise, session persistence is impossible. This is because IP spoofing allows you to send requests so that the web server can take specific actions.

The method proposed in the present invention is a method of making one request impossible to reuse. The request itself is made in a one-time use form, so that even if the session key is leaked, it cannot be reused, which can fundamentally solve the problem of leaking session information.

By adding information specific to the browser to the request requested by the web client (client) over HTTP, the web server can recognize / authenticate / separate the web browser requesting the request and whether or not to use the request. Make judgment.

The web browser adds unique information to the request header that only one can generate for every request made to the web server. The web server extracts unique information of the browser from the header of the received request to determine validity and use.

6 is a process diagram of one embodiment of a method of secure communication in accordance with the present invention.

In 2.0 of FIG. 6, the plug-in randomly generates a key for encrypting sequence information and encrypts it with the public key of the web server to transmit it to the web server. In 2.3), the web server decrypts the received key information with a private key and stores the encryption key in the session area.

In 3.0), the plug-in encrypts the sequence information with the generated key and adds it to the request. 3. In 2), the web server decrypts the encrypted sequence information with the encryption key stored in the session, and determines whether the information is valid and used.

The encryption key used is three types: public key of web server, private key of web server, and key for sequence encryption. The key for sequence encryption is randomly generated. The key for sequence encryption is shared between the web browser and the web server, and only two need to know. The sequence encryption key can be shared by encrypting / decrypting the public key and the private key of the web server.

In comparison with FIG. 3 and FIG. 6, in FIG. 6, a plug-in program operating in a web browser-dependent manner performs secure communication between a web server and a web browser. In FIG. 3, a relay program operating independently of the web browser is executed. Perform secure communication between the web browser and the web server.

The specific process flow is as follows.

Initialize

When the web browser connects to the web server for the first time, the plug-in module is activated. The plug-in initializes the sequence number to be assigned on a per request basis.

2. Negotiation

The plug-in randomly generates a seed encryption key at startup, encrypts it with the public key of the web server, and sends it to the web server. The web server decrypts the encrypted seed key with the private key and stores the encrypted seed key in an area such as a session. Servers and plug-ins can request new negotiations if necessary, but require previous negotiation information.

3. Send Request

The plug-in built into the web browser increments the sequence number each time a request is sent to the web server. The web browser encrypts the sequence numbers, random values, and their HASH (SHA) values with the seed and adds them to the request's header.

4. Verify Request

The web server extracts the encrypted value from the request's header. The encrypted value is decrypted using the seed key stored in the session. The validity of the request is checked through a hash check on the decrypted data, and the sequence number included in the decrypted data is checked to determine whether or not the request is used. The server manages the sequence number used in a proper way so that it can be reused.

5. Finalize

When the session is terminated, the plug-in module of the web browser is stopped and the web server discards the negotiation information and the sequence information stored in the session.

Although the present invention has been described in terms of some preferred embodiments, the scope of the present invention should not be limited thereby, but should be construed as modifications or improvements of the embodiments supported by the claims.

1 is a schematic diagram illustrating a general flow of data in HTTP.

2 is a schematic diagram illustrating a configuration in which a web browser and a web server communicate using cookies.

3 is a schematic block diagram illustrating the use state of one embodiment of a secure communication system in accordance with the present invention;

4 is a schematic block diagram illustrating an embodiment of one aspect of a secure communication system in accordance with the present invention.

5 is a schematic block diagram illustrating an embodiment of another aspect of a secure communication system in accordance with the present invention.

6 is a process diagram of one embodiment of a method of secure communication in accordance with the present invention.

Claims (17)

An identification information extracting unit for extracting identification information of the request message set to distinguish each request message of the web browser from the request message transmitted from the web browser; And And a response message transmitter for transmitting a response message corresponding to the request message to the web browser when the identification information satisfies a predetermined identification criterion. The method of claim 1, wherein the identification information extraction unit An encryption value extraction unit for extracting an encryption value of identification information from the request message; And And a decryption unit for decrypting the extracted encryption value. The method of claim 2, The decryption is performed using an encryption key transmitted from the web browser. The method of claim 3, wherein The encryption key is encrypted with the public key of the web server. An identification information generation unit for generating identification information of a request message configured to distinguish each request message of the web browser from each other when the web browser accesses a web server; And And an identification information inserting unit including the identification information in a request message transmitted from the web browser to the web server. The method of claim 5, And the identification information insertion unit encrypts and inserts the identification information. The method of claim 6, And an encryption key transmitter for transmitting an encryption key for decrypting the encrypted identification information to the web server. The method of claim 7, wherein The encryption key is encrypted with a public key of the web server. An identification information extraction step of the web server extracting identification information of the request message set to distinguish each request message of the web browser from the request message transmitted from the web browser; And And transmitting a response message corresponding to the request message to the web browser when the web browser identification information satisfies a predetermined identification criterion. The method of claim 9, wherein the extracting the identification information Extracting an encryption value of identification information from the request message; And And decrypting the extracted encryption value. The method of claim 10, And wherein the decryption is performed using an encryption key transmitted from the web browser. The method of claim 11, The encryption key is encrypted with the public key of the web server. An identification information generating step of generating, by a computer program on a communication terminal on which a web browser is executed, identification information of a request message set to distinguish each request message of the web browser from each other when the web browser accesses a web server; And And including the identification information by the computer program including the identification information in a request message sent by the web browser to the web server. The method of claim 13, And including the identification information comprises encrypting the identification information. The method of claim 14, And the web browser transmits an encryption key for decrypting the encrypted identification information to the web server. The method of claim 15, The encryption key is encrypted with the public key of the web server. A recording medium having recorded thereon a computer readable program for executing the method of any one of claims 9 to 16.

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