JPH10322325A - Encryption authentication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the encryption authentication system in which authentication information is prevented from being stolen on a data transfer path so as to secure the security against a simulated server and a simulated client. SOLUTION: A client side public encryption key is sent from a client to a server, and the server makes a question to the client by using the client side public encryption key. A server side public encryption key is sent from the server to the client by using the client side public encryption key. The answer to the question is sent from the client to the server by using the server side public encryption key and when the answer from the client is correct, the encryption ken, the server and the client are authenticated. The server side public encryption key may be sent in a form of a tally.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cryptographic security between a server and a client, and more particularly, to establishing authentication between a client and a server.

[0002]

2. Description of the Related Art Communication networks are rapidly developing, as represented by the Internet and intranets. Along with that, new transaction forms such as an electronic transaction encryption key and electronic money are about to occur.

[0003] The Internet is a network derived from the US DARPA, and its protocol is TCP / IP.
Is used. As a feature, a bucket brigade method is used for data transfer. That is, each node relays the data packet toward the target terminal. Therefore,
At each of the nodes located between the source node and the destination node of the data, it is relatively easy to steal or falsify the data packet.

[0004] Intranet is a technology in which the technology of the Internet, which is basically open, is introduced into a closed or partially closed network.

[0005] A conventional basic authentication procedure performed by a client to identify which client the server accesses when accessing the server will be described below with reference to FIG.

[0006] In step S102, the client accesses the server. In step S104, the server
The client requests an identifier (ID) and an identifier guarantor (password). In step S106, the client transmits the ID and the password to the server. Steps
In S108, the server determines whether the combination of the ID and the password from the client is correct. If it is determined in step S108 that the combination of the ID and the password from the client is correct, step S110
In, the server allows the client access.
At the same time, the server understands who the client is. Here, the server is, for example, a bank, a host computer, a terminal computer, a personal computer, and the like, and the client is, for example, a human, a terminal computer, and the like.

In the above method, the ID and the password are used for authentication of the client. However,
If your ID and password are stolen along the way,
There is no guarantee that correct authentication will be performed thereafter.

Further, simply encrypting the transmitted data simply creates a new ID and password required for identification, and steals the data on the data transfer path. Not done. That is, encryption is
This is effective only when “data obtained by restoring encrypted data” is important. Encryption is meaningless when the encrypted data itself is important, as in the case of authentication. This is because what is needed to impersonate the party of the communication is not the contents of the decrypted encrypted data, but the encrypted data itself. If you steal the encrypted data and send the encrypted data to the server, the authentication will succeed.

In order to solve the above problems, various methods have been proposed as methods for establishing authentication between a client and a server to secure data communication, which will be described below.

[0010] One method is an encryption method using a common encryption key represented by DES. In this case, the encryption method uses the same common encryption key for encryption and decryption,
This is the most common encryption method. However, even in this method, if the common encryption key is stolen, there is no guarantee that the correct authentication will be performed on the encryption key.

Therefore, as a more secure cryptographic authentication method,
This is an encryption method using a public encryption key represented by RSA and a secret encryption key. Here, the public encryption key is an encryption key of an encryption key when encrypted, and the secret encryption key is an encryption key to be used as an encryption key when decrypting the one encrypted with the public encryption key. Determining a secret encryption key from a public encryption key is difficult and more reliable than the DES method. However, it is still not enough when considering e-commerce.

As described above, when performing the above-described authentication in all networks such as the Internet and an intranet, or in a computer system, if the information necessary for authentication is stolen on the data transfer path, the information is transferred. Using it, it is possible to impersonate others. In such a case, reliable authentication is performed without an encryption key, which is the biggest bottleneck in performing electronic commerce.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. Accordingly, it is an object of the present invention to prevent theft of authentication information on a data transfer path, and to provide an encryption authentication method which has little effect on the establishment of authentication even if it is stolen. Also,
It is another object of the present invention to provide a cryptographic authentication method that can establish security for a simulated server and a simulated client in an open network or the like.

[0014]

According to the encryption authentication method of the present invention, a client-side public encryption key is transmitted from a client to a server, and a query is issued from the server to the client using the client-side public encryption key. . Using the client-side public encryption key,
A server-side public encryption key is also transmitted from the server to the client. Using the server-side public encryption key, an answer to the question is sent from the client to the server, and if the answer from the client is correct, an encryption key and authentication between the server and the client are established.

Further, in the encryption authentication system of the present invention, the client side public encryption key is transmitted from the client to the server. Using the client-side public encryption key,
The server asks the client a question,
A first tally for a server-side public encryption key is transmitted from the server to the client using the client-side public encryption key. The client generates the server-side public encryption key from the received first tally and the retained second tally, and answers the question using the generated server-side public encryption key. Send from the client to the server. When the answer from the client is correct, authentication is established between the server and the client.

In the above-mentioned encryption authentication system, the client generates the server-side public encryption key using the first and second tally marks and a predetermined algorithm.

In the above-mentioned cryptographic authentication system, the server dynamically generates the first tally based on the second tally on the client side.

In the above-mentioned cryptographic authentication method, after authentication is established, a common encryption key is transmitted from the server to the client, and subsequent communication is performed using the common encryption key.

In the above-mentioned cryptographic authentication system, the server generates the common cryptographic encryption key dynamically.

In the above-mentioned encryption authentication system, the client-side public encryption key is dynamically generated by the client.

[0021] In the above cryptographic authentication method, the server is provided with a plurality of questions, and the server transmits at least one dynamically selected question to the client.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An encryption authentication system according to the present invention will be described below with reference to the drawings.

As described above, simply encrypting data merely creates a new ID and password required for identification, and the data can be stolen on the transfer path. Absent. Therefore, the encryption authentication method according to the first embodiment of the present invention is executed in the following procedure.

When authentication is to be established between the server and the client, in step S2, the client generates a client-side public encryption key dynamically and randomly and sends it to the server. In step S4, the server issues a question to the client using the client-side public encryption key. The "question" has the same role as the above-mentioned ID and password. Therefore, the question may be a conventional ID and password.

At least one question, generally a plurality of questions, is prepared. At least one of the questions is asked. Of course, in this case, the number of questions may be one. It is inconvenient for a client operated by a human to have multiple questions, but for computers and the like, it is more secure to ask some of the multiple questions. Further, a dynamically determined number of questions from among a plurality of questions may be asked. Security can be further enhanced if a dynamically determined number of dynamically selected questions are asked.

In step S4, the server also sends the server side public encryption key to the client.

Step S6, the client sends the answer to the question to the server using the server-side public encryption key.

If the answer to the question is correct, the authentication of the client is established, and the server dynamically generates a common encryption key to be used for future communication in step S8, and transmits the common encryption key to the client-side public encryption key. Sent to client using key. When the client receives the common encryption key, data communication can be performed using the common encryption key.

By performing the above procedure, the information necessary for authentication becomes the data obtained by decrypting the encrypted data, that is, the information before encryption. Can no longer be exploited. As a result, even if data is stolen on the data transfer path, it cannot be exploited as long as the encryption method is reliable.

Further, the client-side public encryption key is dynamically generated, and thus differs every time. Therefore, the reliability can be further improved. Further, since the common encryption key transmitted from the server is dynamically generated after the authentication is established, the reliability is further improved.

As described above, in the encryption authentication system of the present invention,
There is an effect that authentication can be performed even on a data transfer path on which security is not established. Also,
At the time of authentication, communication is performed using a public encryption key and a secret encryption key, and after authentication is established, communication is performed using a common encryption key. Therefore, the overall processing required for data communication can be reduced.
Therefore, there is an effect that the load on the computer is reduced.

Next, an encryption authentication system according to a second embodiment of the present invention will be described.

In the first embodiment, the effect is obtained that the authentication can be performed even on a route on which the security on the data transfer route is not established.
Security has not yet been established for simulated clients. If a simulation server is used in the middle of a communication path, it is possible to obtain information required for authentication from a client. The reverse is also possible.

Therefore, in the cryptographic authentication method according to the second embodiment, a method for establishing security for a simulated server and a simulated client will be described.

In order to establish security for the simulated server / simulated client, instead of checking whether it is simulated or true, it is necessary to create a situation where the simulated server / simulated client must be a true server / true client. In this case, there is a method of guaranteeing the client and server by the third party server, but if there is a bad person on the transfer route (especially immediately before the server when delivering data to the server), all the transfer data The decision is to be taken because the packet is in the hands of the bad guy. In other words, there is no point in simulating a third party.

The "tally" method authentication is used there. The specific procedure is as follows.

When it is desired to establish authentication between the server and the client, in step S12, the client generates a client-side public encryption key dynamically and randomly and transmits it to the server.

In step S14, the server issues a question to the client using the client-side public encryption key. This “question” is the same as the question in the first embodiment. At this time, the server transmits the tally to the client using the client-side public encryption key.

Step S16, the client obtains a server-side public encryption key from the tally from the server.
For example, a server-side public encryption key is derived by applying a predetermined algorithm to a tally from the server and a tally promised between the server and the tally. The client sends the answer to the question to the server using the obtained server-side public encryption key.

If the answer to the question is correct, client authentication is established up to step S16. At that time, in step S18, the server dynamically generates a common encryption key to be used for future communication, and transmits the common encryption key to the client using the client-side public encryption key. When the client receives the common encryption key,
Thereafter, communication can be performed using the common encryption key.

As described above, the difference from the encryption authentication method in the first embodiment is step S14.
The server side tally is transmitted to the client at the same time as the "question". The tally is possessed by both the server and the client, and when combined, provides a "server-side public encryption key" that is used when transmitting the answer to the server question.

As a specific example, assuming that the server side tally is SS and the client side tally is CS, (server side public encryption key) = SS XOR CS (XOR is exclusive OR). The function for calculating the server-side public encryption key is not limited to XOR. If more sophisticated algorithms are used, the degree of security can be increased.

In the case of a true server, since the tally of a true client is known, the server-side public encryption key after derivation can be changed every time by generating the tally dynamically.

If there is no relationship between the true server and the true client, the simulated client cannot obtain the server-side public encryption key used at the time of reply. That is, since the tally of the true client is unknown, the server-side public encryption key cannot be derived. In addition, since the tally of the true client is unknown, the simulation server cannot obtain a correct “answer” (answer from the true client to the true server).

The cryptographic authentication system according to the present invention can be applied to various types of authentication. The following describes an example of bank transfer on the Internet. The server is a bank on the Internet, and the client is a home or business terminal. Let the user be the person operating the terminal. In the following description, the authentication applet is an application that operates on the client side.

The client accesses the home page of the bank using a Web browser. At the same time Java
An authentication dialog realized by an applet or ActiveX control appears. Software that generates the authentication dialog (hereinafter, referred to as an authentication applet) performs authentication according to the procedure of the cryptographic authentication method of the present invention. The authentication applet is a Java applet, and
If it is downloaded, it is checked for tampering with the transition to JDK1.1.

Here, when the user selects remittance, the authentication applet generates a client-side public encryption key from a true random number, user-specific data, and the like. Here, it is created for each authentication to further enhance security. The authentication applet sends the client-side public encryption key to the server.

Next, the authentication applet requests the user for his account number and PIN. The authentication applet requests a tally from the server. The authentication applet is
Deriving the server-side public encryption key from the tally. Then, the authentication applet sends the account number and the password to the server using the server-side public encryption key.

Thereafter, when the authentication applet receives the common encryption key and the identification code from the server (in the subsequent communication between the server and the client, the encryption communication using this common encryption key is performed), the authentication applet sets Ask the user for the remittance account number and amount. After that, the authentication applet sends the account number of the remittance destination to the server.

Upon receiving the remittance destination information from the server,
The authentication applet displays the remittance destination information to the user and requests confirmation. If the user determines that the remittee / amount is OK, the authentication applet sends the remittee, the amount, and the identification code to the server.

Upon receiving the confirmation information from the server, the authentication applet displays the confirmation information to the user. Thus, the bank remittance process is completed.

Here, the widely and widely used Web
Examples are given assuming implementation with a browser and Java from Sun Microsystems or ActiveX components from Microsoft.

Next, the cryptographic authentication system of the present invention will be described using electronic money as an example. Here, the server is the issuing organization of the electronic money, the client is the IC card, and the user is the IC card owner. In this case, the cash register can be regarded as a node. Therefore,
The encryption authentication method of the present invention can be applied to such a form.

In this example, at the time of communication between the IC card and the issuing organization of electronic money, the cash register is relayed. If this cash register is a bad guy, it is a data transfer path, so plagiarism / falsification is possible,
There is a possibility that an unreasonable amount may be paid, but if the encryption authentication method of the present invention is applied, this security hole can be filled. Naturally, if the encryption authentication method according to the second embodiment is applied, security can be maintained even for a simulated IC card and a simulated electronic money issuing organization.

As described above, the encryption authentication method of the present invention
Although it can be used for authentication of computers in general, it is particularly applicable to the following examples.

In a commercial server, confirmation between the direct parties of the transaction of goods and services. In this case, the contents of the authentication include the authentication of the mall, the authentication of the ordering server, and the like. The assumed certificate authority is a third party organization, and also includes a network operator.

Confirmation at the time of settlement in bank / credit related transactions. In this case, the contents of the authentication include card holder authentication, member store authentication, and financial institution authentication. Possible certificate authorities are banks and credit companies, and also include third-party institutions that are outsourcing from financial institutions.

Confirmation of the partner of the electronic mail in the security mail. In this case, the content of the authentication is individual authentication. The assumed certificate authority is a third party organization including a network operator.

Confirmation of group members in groupware. In this case, the content of the authentication is personal confirmation,
Possible certificate authorities are companies, organizations, and third parties that are outsourcing from companies and organizations.

Confirmation at the time of administrative service in public business. In this case, the contents of the authentication are individual authentication and organization authentication, and the assumed certificate authority is a public organization.

[0061]

As described above, according to the present invention, it is possible to perform secure authentication and communication even in a network in which security on a transfer path is not established. Further, theft and spoofing of authentication information by the simulation server and the simulation client can be prevented. This can further accelerate the development of an electronic network society.

[Brief description of the drawings]

FIG. 1 is a timing chart for explaining a procedure of an encryption authentication method according to a first embodiment of the present invention.

FIG. 2 is a timing chart for explaining a procedure of an encryption authentication method according to a second embodiment of the present invention.

FIG. 3 is a timing chart for explaining a procedure of a conventional encryption authentication method.

Claims (8)

[Claims] 1. transmitting a client-side public encryption key from a client to a server; using the client-side public encryption key to query the client from the server; and using the client-side public encryption key Transmitting a server-side public encryption key from the server to the client; transmitting the answer to the question from the client to the server using the server-side public encryption key; and A cryptographic key comprising, if the answer is correct, establishing an authentication between the server and the client. 2. transmitting a client-side public encryption key from a client to a server; using the client-side public encryption key to ask a question from the server to the client; and using the client-side public encryption key. Transmitting a first tally for the server-side public encryption key from the server to the client; and obtaining the first tally received and the second tally retained from the server to the server. Generating a public encryption key, using the generated server-side public encryption key, transmitting the answer to the question from the client to the server;
And establishing an authentication between the server and the client when the answer from the client is correct. 3. The encryption authentication method according to claim 2, wherein the client generates the server-side public encryption key using the first and second tally marks and a predetermined algorithm. 4. The cryptographic authentication method according to claim 2, wherein the server dynamically generates the first tally based on the second tally on the client side. 5. The cryptographic authentication method according to claim 1, further comprising, after the authentication is established, transmitting a common cryptographic encryption key used for subsequent communication from the server to the client. 6. The encryption authentication method according to claim 5, wherein the common encryption encryption key is dynamically generated by the server. 7. The encryption authentication method according to claim 1, wherein the client-side public encryption key is dynamically generated by the client. 8. The server is provided with a plurality of questions, wherein the server has at least one dynamically selected question.
8. Sending one question to the client.
The cryptographic authentication method according to any of the above.