JP2002055958A - Three-password authentication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that it is very difficult to authenticate a client since the Internet is an open network and the general public can access it from various places. SOLUTION: It is premised here that an original server program and an original client program are both generated. At least three pieces of information on a user ID, a notice password, and a non-notice secret password are embedded in the client program. The server program is associated with a database which has at least four data items of the user ID, a user-defined password, the non- notice secret password, and an illegal access counter. The client program inputs two passwords which are the notice password and user-defined password and checks the adequacy of the notice password. The server program checks the adequacy of two passwords which are the non-notice secret password and user- defined password which are sent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for authenticating a client attempting to connect to a server via the Internet on the server side, and a technique for recognizing unauthorized access.

[0002]

2. Description of the Related Art The Internet is an open network, and an unspecified number of people can access from various places. This makes client authentication a very difficult problem. At present, authentication methods for clients accessing an Internet server are widely used, including a method using one password and a method using advanced encryption such as SSL.

[0003]

However, in the method using one password, it is not possible to identify who has accessed the password, so that an unauthorized access person may try to access the password many times. , There is a risk that the password will be cracked.

[0004] On the other hand, in a system using advanced encryption such as SSL, these problems are somewhat improved. By issuing a client certificate to each client and having that information sent to the server, the client can be authenticated. However, this approach also has its weaknesses.
That is, because of the high encryption, the CPU load for decryption is very large. This means that attacks that hinder server service provision (DoS
Attack).

At present, there are several issuing organizations of client certificates, and each issuing organization generates a client certificate using a private key dedicated to each issuing organization. Think about what happens if the private key is exposed. Forged client certificates can be easily created. In other words, the public key-private key method generally used in advanced encryption technology such as SSL has a serious defect that if the private key is exposed, enormous damage will occur. Have been.

According to the present invention, in order to solve such a problem, the authentication of the client can be surely performed, the CPU load is smaller than that of an advanced encryption technique such as SSL, the public key-private key method is not used, and It is an object of the present invention to provide a client authentication technology which has many defense walls against unauthorized access and can be easily used on an open network such as the Internet.

[0007]

Means for Solving the Problems In order to solve the above problems, the present invention assumes that both a server program and a client program are created by themselves. And unlike the SSL client certificate, the client authentication information is embedded in the client program, not just as data. In other words, create client programs for each client. It may be better to separate client credentials as mere data, like client certificates. However, the damage caused by forging a client certificate when a private key is exposed is immeasurable. Therefore, in the present invention, it has been decided that the client authentication information is distributed and managed by the client program and the server. This leaves the risk of unauthorized copying of the client program, but frees the client from being forged. This is because if you do not register the forged authentication information on the server side, the authentication information has no meaning.

First, the configuration of the client program will be described. At a minimum, the client program
Embed the user ID, notification password and non-notification secret password. The user ID is an ID number uniquely assigned by the server administrator to identify the client. The notification password is a password for the client defined by the server administrator and notified to the client in advance. What is an unannounced confidential password?
This is a password for the client, defined by the server administrator and not given to the client in advance.

Next, the configuration of the server program will be described. The server program associates an array or list of data structures with a minimum of four data items: a user ID, a user-defined password, a confidential secret password, and an unauthorized access counter. Of these, the user ID and the secret password for non-notification are the same as those embedded in the client program. A user-defined password is a password that can be freely defined and changed by the client, and is set by the client using the client program. Also, the unauthorized access counter is incremented each time the client accesses the server using its own client program and the access is denied due to a wrong password, and every time the client obtains the access permission by entering the correct password, It is cleared to 0.

Next, the client authentication procedure will be described. First, the client information other than the password embedded in the client program is displayed on the screen. For example, "This program has a user ID
Is the XXX number and is only for customers whose name is XXX. Lending or transfer to another person is prohibited. Is displayed. This display lets clients know that this program is their own. Next, ask the client to enter a notification password and a user-defined password. Then, it performs a comparison check between the entered notification password and the notification password embedded in the client program. Then, if this comparison check is passed, the server program sends at least three pieces of information to the server program: the entered user-defined password, the user ID embedded in the client program, and the non-notifying secret password.

The server program extracts a client-specific data structure from the array or list of linked data structures using the transmitted user ID as a key. If the value of the unauthorized access counter item included in the data structure is larger than a predetermined value, the connection with the client program is disconnected. If the password is smaller than the specified value, a comparison check is performed between the sent user-defined password and the non-secret secret password, between the user-defined password and the non-secret secret password included in the data structure.

As a result of the comparison check, if both the user-defined password and the non-notifying secret password are valid, the server program establishes a session with the client program, and thereafter performs normal data transmission and reception. Also clears the unauthorized access counter item included in the data structure to 0.

If the unchecked secret password is valid as a result of the comparison check, but the user-defined password is incorrect, it is possible that the client program has passed into the hands of a third party who is not a legitimate client. Means that there is. This is because legitimate clients rarely get the wrong user-defined password. However, legitimate clients sometimes make mistakes in their user-defined passwords. Therefore, how many times in a row,
In order to remember whether the user-defined password is incorrect, the value of the unauthorized access counter item included in the data structure is incremented.

The above is the client authentication procedure according to claim 1 of the present invention. However, the method according to claim 1 has at least three problems. First, the client program does not encrypt the user-defined password and the secret confidential password when sending it to the server program. By monitoring the flow of data in the middle of the communication path, there is a risk that these passwords, which should be kept secret, can be easily exposed. Second, if a failure is detected in the comparison check of the non-notifying confidential password in the server program, it means that the client is not using the client program created by the server administrator. For example, the client may have modified the client program, created the data to be sent to the server, and accessed the server without using the client program. Some countermeasures should be prepared for such unauthorized access. Third, the validity check of the notification password in the client program is completed in the client program and does not make a server connection. This is one strategy to reduce unauthorized access to the server program, but on the other hand, if it is found that it is a validity check completed in the client program,
There is a risk that you may try again and again until you know the correct password.

First, in order to solve the first problem, there is a method in which a challenge-response authentication method is incorporated. The feature of this method is that, in the client program, the user-defined password to be kept secret and the secret secret password are not sent to the server program, but only the user ID of the client is sent to the server program. User-defined passwords and non-secret confidential passwords do not flow on the communication path, so even if someone monitors the flow of data, there is no need to worry about being detected.

In order to solve the first problem, a part or all of communication data transmitted and received between a client program and a server program is encrypted in a predetermined manner. There is also an encryption method using an algorithm. In this way, even if the data flow is monitored in the middle of the communication path, the content of the data is prevented from being easily guessed, and the reliability is improved.

Further, in order to solve the second problem, as a sixth function of the server program, the third function comparison check is performed when the non-notification confidential password is incorrect in the third function comparison check. If so, add a function to get the IP address of the sender of the packet and keep a record in the log. In this way, we can help identify criminals who intentionally attempt unauthorized access,
The chances of getting some clues expand.

Further, in order to solve the third problem, when the comparison check of the second function is not passed as the fourth function of the client program, no data is obtained. Connecting to a specially set Internet server that does not return, or a fictitious IP that does not exist anywhere
It is a good idea to add a dummy connection function, such as trying to access an address. In this way, the person who enters the incorrect notification password can be made to think that he / she is connected to the server program even though he / she is not actually connected to the server program.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a server administrator must create a client program for each client. To do so, the user code must be included in the source code of the client program.
It is a good idea to provide a constant storage area to store at least three of D, the notification password, and the non-notification confidential password, and enter the client-specific data for each client in that area. At this time, the notification password and the non-notification confidential password should be generated as randomly as possible. Because if you have a rule, you can easily guess another password if you can't find the rule. In addition to the above three constant storage areas, there should be as many constant storage areas as possible to store dummy data of indefinite length. This breaks the rule that when a client program is opened with a binary editor, there are always three constant storage areas at a given location: a user ID, a notification password, and a non-notification secret password.

Next, an array or list of data structures linked with the server program is constructed. Set the same data items as those embedded in the client program in the data items of the user ID and non-secret confidential password in this data structure. Also, 0 is set as an initial value in the unauthorized access counter item. You can also set an initial value for the data item of the user-defined password, but if possible, let the client set it through a client program.

Finally, a method of distributing the created client program to the client will be described.
Since the created client program is dedicated to the client, it must be delivered without being handed over to a third party. for that purpose,
It can be said that it is a reliable method to send it by mail on a medium such as a CD-ROM. In addition, using the one-time download technique for sending via the Internet, it is possible to easily distribute client-specific programs without handing them over to third parties. (For details of this technology, please refer to the materials submitted on August 11, 2000, Title of Invention-One-time Download Method, Inventor-Yasuhiro Ishikawa.)

[0022]

[Effect of the Invention] In the present invention, three passwords are used, and each one of them has an effect to solve the problem.

First, regarding the notification password, this password is embedded in the client program, but is not managed at all on the server side. In other words, this password prevents unwanted access to the server program, and prevents DoS (service disruption).
It has the effect of protecting the server from attacks.

Next, the non-notifying secret password, which is defined by the server administrator and embedded strictly in the client program. This password is also managed on the server side. The server program can recognize if the client program has been altered or forged, by checking the validity of the non-secret confidential password sent from the client program.

Next, the user-defined password is a password that can be freely defined and changed by the client, and is managed only on the server side. The server program may use a non-secret confidential password sent from the client program, but if the user-defined password is incorrect, the sender of the data may illegally copy another client program and use it. If there is, you can recognize. Of course, legitimate clients may have accidentally entered the wrong user-defined password. Therefore, it counts how many times a user-defined password has been mistaken for consecutive times, and manages it with an unauthorized access counter item. If the value of this item is equal to or greater than the predetermined value, the server program recognizes that the data sender has illegally copied and used the client program of another person and accepts subsequent access. It has the effect of protecting the server from unauthorized access.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a client program and a server program.

Claims (5)

[Claims] 1. A client program in which at least three pieces of information of a user ID, a notification password, and a non-notification secret password are embedded, and four data of a user ID, a user-defined password, a non-notification secret password, and an unauthorized access counter It consists of a server program that works with an array or list of data structures with a minimum of items. The client program has at least the following three functions. First, a function of displaying client information such as a user ID embedded in the program. Second, a function that accepts the input of the notification password and performs a comparison check with the notification password embedded in the program. Third, accepting the input of the user-defined password, and if the second function has passed the comparison check, the user ID,
A function to send at least three pieces of information, a user-defined password and a non-secret secret password, to the server program The server program has at least the following five functions. First, based on the user ID information transmitted from the client program, a function of extracting a data structure corresponding to the client from an array or list of interlocking data structures. Second, check whether the value of the unauthorized access counter item included in the data structure extracted by the first function does not exceed the prescribed value predetermined by the server administrator, and if it exceeds, Function to disconnect the connection with the client program. Third, a function to compare the user-defined password and non-secret confidential password sent from the client program with the user-defined password and non-notified confidential password included in the data structure extracted in the first function. . Fourth, if the checks of the second and third functions are passed, a session with the client program is established, normal data communication is performed, and the unauthorized access counter item of the data structure is cleared to zero. function. Fifth, a function for incrementing the unauthorized access counter item of the data structure when the non-notifying confidential password is valid in the third function comparison check but the user-defined password is found to be incorrect. A three-password authentication method including a client program and a server program having the above functions. The expression “array or list of data structures” includes a database. 2. The third function of the client program according to claim 1, further comprising: receiving an input of a user-defined password;
If the comparison check of the second function has been passed, the server program sends information containing at least the user ID and at least the user ID to the server program without including the user-defined password and the non-notifying confidential password. Waits for the returned challenge string, and when the challenge string arrives, encrypts it using the user-defined password and the non-secret secret password as keys, and returns the encrypted string to the server program as a response string. The third function of the server program according to the first aspect of the present invention is to change a challenge character string randomly, transmit the challenge character string to the client program, and wait for a response character string to be returned from the client program.
In the meantime, the challenge character string is encrypted using the user-defined password and the non-notifying secret password included in the data structure extracted by the first function as keys, and an answer character string is generated. Then, when a response string is returned from the client program, the function is changed to a function of performing a comparison check between the response string and the answer string, and a three-password authentication method incorporating a challenge-response type authentication method. 3. The three-password authentication method according to claim 1, wherein part or all of communication data transmitted and received between the client program and the server program is encrypted by a predetermined encryption algorithm. . 4. As a sixth function of the server program,
3. The method according to claim 1, further comprising a function of acquiring an IP address of a sender of the packet and recording the packet in a log when the non-notification secret password is found to be incorrect in the comparison check of the third function. 3. A three-password authentication method described in 3. 5. A fourth function of the client program is to connect to a specially provided Internet server that does not return any data when the comparison check of the second function is not passed, or is not present anywhere. 5. A function for making a dummy connection by deceiving a client by attempting to access a fictitious IP address, for example, as if connecting to a server program, and adding a dummy connection function. 3 password authentication method.