JPH0470949A - Oblique access preventing system - Google Patents

Abstract

PURPOSE:To prevent the oblique accesses applied from the non-subscribed terminals by deciding whether the random number received from a terminal requesting an access is reasonable or not and granting the access if the random number is reasonable. CONSTITUTION:A subscribed terminal 12 sends the random number received from a random number generating means 15 and set to a memory 12a to a host computer 11 when an access is requested to the computer 11. The computer 11 compares the received random number with the random number set at its own memory 11a and then grants the access request of the terminal 12 when the coincidence is obtained between both numbers. That is, the means 15 sends no random number to a non-subscribed terminal 13 and therefore the computer 11 sends no random number to an access request of the terminal 13. No, coincidence of collation is substantially secured even if a random number is sent to the terminal 13 and therefore the access request of the terminal 13 is never granted. Thus the oblique accesses can be effectively prevented.

Description

[Detailed Description of the Invention] Table of Contents Overview Industrial Application Fields Conventional Technology Problems to be Solved by the Invention Means for Solving the Problems (Fig. 1) Functional Examples (Figs. 2 to 9) ) Summary of effects of the invention Regarding an unauthorized access prevention method in a computer system in which a plurality of terminals access a host computer via a communication network, the present invention aims to prevent unauthorized access from non-subscriber terminals. In an unauthorized access prevention method for a computer system that may be accessed via a communication network from multiple subscriber terminals that have registered for subscription and non-subscriber terminals that have not registered for subscription, random numbers are used at regular or irregular time intervals. is generated and the random number is sent to the host combination.
The subscribing terminal sends the random number it owns to the host computer when requesting access to the host computer, and the host computer receives the random number sent from the subscriber terminal and the random number it owns. and configure it to allow access only if they match.

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for preventing unauthorized access in a computer system in which a plurality of terminals access a host computer via a communication network.

2. Description of the Related Art Systems in which a host computer can be accessed via a general public line and provided with various services are becoming widely used. Such systems provide services to people who intend to use them for legitimate purposes, but because they use public lines, so-called "backers" may use them for purposes other than legitimate purposes. They access host computers for the purpose of security and infiltrate malicious programs called "viruses," causing various problems such as system destruction and leakage of confidential information, which has become a major social problem.

Therefore, there is an urgent need to take effective measures to prevent unauthorized access by "backers" as described above.

Conventional technology Generally, when a line is set up between a host computer and a terminal, the host computer prompts the user to enter a personal identification number (ID number) and password, and the user registers in advance in response to this. Enter the number or code. After confirming whether the ID number is registered, the host computer checks whether the password corresponds to the ID number, and if the password is valid, allows access from the terminal.

However, if a so-called "backer" or the like obtains the ID number and password by some means, there is no way to prevent unauthorized access. For this reason, subscriber information such as a telephone number assigned by a telephone exchange network etc. to each terminal that has registered to subscribe to the system is registered in advance with the host combination, and when requesting access to the host computer, The subscriber information of the terminal that issued the access request is received from the telephone exchange network, etc., the subscriber information is verified in the host computer, and access is permitted only when a match is confirmed. A method has been proposed (Japanese Unexamined Patent Publication No. 171247/1983). Note that in this method as well, verification using the ID number and password is used in combination.

In addition, for each terminal that has registered to subscribe to the system, information for identifying the terminal (hereinafter referred to as terminal code) is registered in advance in the host computer, and the terminal is physically held and access to the host computer is performed. A method has also been proposed in which the terminal code is sent along with the above ID number and password at the time of the request, the terminal code is also verified on the host computer, and access is permitted only if a match is confirmed. (Japanese Patent Application Laid-Open No. 63-301350).

Problems to be Solved by the Invention However, according to the conventional unauthorized access prevention method as described above, it is necessary to register the terminal code and subscriber information for each terminal in the host computer, which reduces the number of registered subscribers. When the number of subscribers is enormous, the memory load on the host computer is large, and the comparison and verification process is performed by sequentially comparing the sent terminal code with multiple pieces of subscriber information registered in the memory of the host computer. Therefore, there is a problem in that the processing takes time and the user has to wait for a long time.

The present invention has been made in view of these points, and aims to provide a method that can effectively prevent unauthorized access after solving the above problems.

Means for Solving the Problems Please refer to the principle diagram of the present invention shown in FIG. The method of the present invention is a method for preventing unauthorized access in a computer system that may be accessed via a communication network 14 from a plurality of subscriber terminals 12 that have registered to subscribe to a host computer 11 and from non-subscriber terminals 13 that have not registered to subscribe to a host computer 11. be. Then, generate random numbers at regular or irregular time intervals,
A random number generating means 15 is provided for sending the random number to the host computer 11 and each subscriber terminal I2. The host computer 11 and each subscriber terminal 12 have their own memo Jlla.
, 12a is set with the random number sent from the random number setting means 15.
Hold. When the subscribing terminal 12 requests access to the host computer 11, it sends a random number it owns to the host computer 11, and the host computer 11 compares the random number sent from the subscribing terminal 12 with the random number it owns and determines that they match. Access is permitted only if the

Operation When the subscriber terminal 12 requests access to the host computer 11, the random number generator 15 sends the memo IJ.
12 The random number set in a is sent to host computer 1.
1, and the host computer 11 receives this random number and its own memo! Compare with the random number set in Jlla, and if they match, allow access.

Since the random number generation means 15 does not send random numbers to the non-subscribing terminal 13, when an access request is made from the non-subscribing terminal 13, the random number is not sent, or even if it is sent, verification is not performed. Since there are almost no cases where the results match, access by the non-subscribing terminal 13 is not permitted.

The random numbers set in the host computer 11 and each subscribing terminal 12 are updated regularly or irregularly, so even if this random number is leaked, access from non-subscribing terminals 13 may be permitted. There is little sex. In addition, the process of comparing the random number sent from the subscriber terminal 12 and the random number held by the host computer 11 only needs to determine whether or not they match, and the time required for this process is very short. There is no need to keep the user waiting.

In FIG. 1, the random number generation means 15 is connected to the communication network 14 independently of the host computer 11, but the present invention is not limited to this, and the random number generation means 15 is connected to the communication network 14 independently of the host computer 11. This can be realized as an internal function of the computer 11, and the host computer 11 can set a random number in each subscriber terminal 12.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a system configuration diagram when the present invention is applied to a computer system that communicates via an 15DN communication network.

The 15DN communication network includes a plurality of 15DN exchanges, and each exchange and the various devices participating in this communication network are connected by a line network (circuit path) and a signal network (signal path). In the figure, each exchange 22, 23, a host computer 26, and user terminals 28, 29 are connected by a line network 24 and a signal network 25. In the 15DN communication network, voice signals and data desired by the user are transferred via the line network 24, and information necessary for line settings and other controls is transferred via the signal network 25. Ru. A random number generator 27 for implementing the present invention is connected to the signal network 25. In the following description, the user terminal 28 is assumed to be a subscribing terminal that is registered as a subscribing member to the host computer 26, and the user terminal 29 is assumed to be a non-subscribing terminal that is not subscribing to the host computer 26.

21 with reference to FIGS. 3 to 5! The functional configuration of the main equipment shown in 1 will be explained.

FIG. 3 is a block diagram showing the functional configuration of the random number generator in FIG. 2. The random number generation device 27 includes a random number generation timer 31, a random number generation section 32, a terminal registration table 33, a confirmation section 34, and a transmission/reception section 35. When the random number generation timer 31 reaches a preset count value, it requests the random number generation section 32 to generate a random number. Random number generator 32
generates one random number in response to the request from the random number generation timer 31, and passes this random number to the confirmation unit 34. Terminal registration table 33
is a table storing destination information of the host computer 26 and all subscriber terminals 28 that have subscribed to this system. The random number generator 32 receives the destination of the terminal (including the host computer) to which the random number should be sent from the terminal registration table 33, and passes it along with the generated random number to the transmitter/receiver 35. The transmitting/receiving section 35 transmits the random numbers and other signals to the signal path 25, or receives the random numbers and other signals sent through the signal path 25. The confirmation unit 34 is for comparing the random number generated by the random number generation unit 32 and the random number received by the transmission/reception unit 35 to confirm that they match.

FIG. 4 is a block diagram showing the functional configuration of the host computer in FIG. 2. The host computer 26 includes a host combinator body 41, a line/connection setting section 42, a reference memory 43, a confirmation section 44, and a transmitting/receiving section 45. Reference memory 43
is a memory that stores random numbers sent from the random number generator 27, and stores the latest random numbers sent (new random numbers).
The first area stores the random number sent immediately before the new random number (
It has a second area for storing the number of former capitals. The confirmation unit 44 uses the random number sent from the terminal 28 and the reference memory 43.
It compares and checks the random numbers stored in , and determines whether they match or not. If they match, the line/connection setting unit 42 is notified accordingly. The line/connection setting unit 42 requests the communication network 21 to set up a line or a connection via the transmitting/receiving unit 45 when the notification is received.

FIG. 5 is a block diagram showing the functional configuration of the subscription terminal 28, which is registered as a subscriber to this system, among the user terminals in FIG. 2. In addition to the terminal main body 51, the subscriber terminal 28 includes a confirmation/update message control section 52, an access memory 53,
and a transmitting/receiving section 54. The access memory 53 is a memory that stores random numbers sent from the random number generator 27, and has a first area that stores the latest random numbers (new random numbers) sent, and a first area that stores the latest random numbers sent (new random numbers), and a first area that stores the latest random numbers sent (new random numbers). It has a second area for storing random numbers (old capital numbers). When the confirmation/update message control unit 52 receives a confirmation message indicating that a correct random number has been sent from the random number generator 27, it erases the old capital number in the second area of the access memory 53. The transmitting/receiving section 54 is connected to the circuit line 24
Alternatively, it transmits and receives random numbers and other signals to and from the signal path 25.

An outline of communication and internal processing between the random number generator and the host computer or subscriber terminal will be explained with reference to explanatory diagrams of random number setting shown in FIGS. 6(a) to 6(C).

First, referring to figure (a), the random number generator 27 generates one random number, and the host computer 26 and each subscriber terminal 2
8, the generated random numbers are sent to each of them. These random numbers are sent via the communication IE 121 (signal path 25), and are sent to the reference memory 4 in the host combiner 26.
3 and is stored in the first area of the access memory 53 in the terminal 28. Note that before storing the random numbers in the reference memory 43 of the host combiner 26 or storing them in the access memory 53 of the terminal 28, the random numbers received last time and stored in the respective first areas are stored as old capital numbers. Assume that the data has been transferred to the second area of .

Next, referring to figure (b), the host computer 2
6 and the terminal 28 take out the new random numbers stored in each memo 1J43.53 and send them back to the random number generator 27, respectively.

The random number generator 27 compares the returned random number with the random number generated by itself to confirm whether the random number has been correctly set.

Referring to Figure (C), if a match is confirmed as a result of this verification, the random number generator 27 sends a TRUE signal to the host computer 26 and terminal 28 indicating that the random number has been correctly set. Send to each. The host combiner 26 that received this TRUE signal starts a service using this random number (new random number or old random number in a predetermined case), and the terminal 26 that received this TRUE signal
will be able to receive services using this random number (new random number).

Next, an outline of communication between the host computer and the terminal and internal processing will be explained with reference to explanatory diagrams of validity confirmation shown in FIGS. 7(a) to 7(C). In the following description, the terminal A is the subscriber terminal 28 that is the source of the access request.

First, referring to figure (a), terminal A receives a connection request message using a random number (
A new random number) is added and sent. The connection request message is sent to the host computer 26 via the communication network 21.

The host computer 26 compares the random number added to this connection request message with the new random number stored in the reference memory 43. Further, in a predetermined case to be described later, the random number added to the connection request message is compared with the new random number and old random number stored in the reference memory 43.

Next, referring to figure (b), the results of the above comparison and verification,
If a match is confirmed, host computer 26
A request to set up a line or a connection with terminal A is issued to the communication network 21, and the communication network 21 sets up a line etc. between the host computer 26 and the terminal.

Referring to Figure (C), an access request message with an ID number and password is sent from terminal A to the communication network 2.
1, the host computer 26 checks the ID number and password, and if the validity is confirmed, permits access to the terminal A.

Note that the predetermined case in the explanation of figure (b) above is
After a random number is generated by the random number generator 27 and set in the host computer 26, the random number generator 27
Before the random number settings for all subscriber terminals 28 are completed, if an access is made from a terminal for which the settings have not been completed, there will be a situation in which access is not permitted even though it is the subscriber terminal 28. Therefore, until the setting of random numbers for all subscriber terminals 28 is completed, if the random number matches either the new random number or the old random number, it is determined to be valid.

Processing by the random number generator, host computer, terminal, and communication network will be described in detail below with reference to FIGS. 8 and 9.

FIGS. 8(a) to 8(e) are flowcharts showing detailed processing when setting random numbers. Note that FIGS. 3 to 5 will be referred to as appropriate.

First, refer to figure (a). In the random number generator 27, various timers such as the random number generation timer 31 and counters for various operations are cleared to zero (step 801), and the count of the random number generation timer 31 is incremented by 1 (step 80).
2). It is determined whether the count value is equal to a preset transmission request count value (step 803), and if not, the count is further incremented by 1 in step 802. If they are equal in step 803, the random number generation timer 31 sends a random number generation request to the random number generation unit 32 (step 804).
. The random number generator 32 receives the destination of the host computer 26 from the terminal registration table 33 (step 806),
A generated random number is added to the destination and sent to the transmitting/receiving section 35 (
Step 807). Add 1 to the message counter in the random number generator 32 (step 808), compare the message counter value with the total number of registered terminals (step 809), and if they do not match, add 1 from the terminal registration table 33. Receive the destination of the subscriber terminal (step 81
0), the process returns to step 807.

If they match in step 809, the transmitter/receiver 35
A message transmission request is issued to (step 811). The transmitting/receiving unit 35 transmits the message to the communication network 21 and sets a confirmation timer (step 812).

Next, refer to (b). This message is from communication network 21
is sent via the signal network 25 of the host computer 26.
, is delivered to the subscriber terminal 28 (step 813).

In the host computer 26, the receiver stores the random number in the received message in the reference memory 43 and (
Step 814), this random number is sent to the transmitting/receiving section 45 (Step 815), and this random number is added to a predetermined message and sent to the random number generator 27 via the signal network 25 (Steps 816 and 820).

On the other hand, in the subscriber terminal 28, the receiver stores the random number in the received message in the access memory 53 and (
Step 817), sends this random number to the transmitter/receiver 54 (step 818), adds this random number to a predetermined message, and sends it to the random number generation bag via the signal network 25! Sent to 27 (
Steps 819.820).

In the random number generator 27, the received random number is sent to the confirmation unit 3.
4 (step 821), and compares the transmitted random number and the received random number (step 822), and if they match, proceed to step 829 in Figure (C) (step 823).
, in step 829, the match counter is incremented by 1 and the process proceeds to step 830.

If they do not match in step 823, the destination of the terminal 28 is determined (step 824), and a mismatch counter for each destination is incremented by 1 (step 825). The count value of the mismatch counter is compared with a preset limit value (step 826), and if the value of the mismatch counter is less than the limit value, the random number is retransmitted and the process returns to step 813. When the limit value is reached, the corresponding terminal 28 is added to the terminal registration table 33.
In step 827), the process proceeds to step 828 in FIG. 8(C), where the total number of terminals in the terminal registration table 33 is subtracted by 1, and the process proceeds to step 830.

In step 830 of FIG. 8(C), the match counter and the total number of terminals in the terminal registration table 33 are compared, and if they match, the process proceeds to step 833, and if they do not match, the confirmation timer expires in step 831. If it has not expired, step 82 in FIG. 8(b) is performed.
Return to 2. If the time has expired in step 831, the terminal 28 for which no random number has been returned is deleted from the terminal registration table 33 (step 832), and a confirmation message is sent to the host computer 26 in step 833.

When the host computer 26 receives the confirmation message (step 834), it sets a random number update timer and starts accepting both new and old random numbers (step 835). A random number update message is sent to the random number generator 27 (step 836). The expiration time of the random number update timer is set in advance in consideration of the time required for the random number generation device 27 to set random numbers for all subscriber terminals 28, and when this time expires, the reference memory 43 is The old random numbers stored in the second area are erased and acceptance of new random numbers only is started (step 837).

When the random number generator 27 receives the random number update message from the host computer 26 (step 8
38), receives the destination from the terminal registration table 33 and sends the 1 & 12 messages to the terminal 28 (step 83).
9). Add 1 to the confirmation counter (step 840
), the value of the confirmation counter is compared with the total number of terminals in the terminal registration table 33 in step 841, and if they do not match, the process returns to step 839. If they match, an update timer is set and the confirmation message is not sent. Abort (step 842).

Refer to FIG. 8(d). At the terminal 28 that has received the confirmation message from the random number generator 27 (step 8
43) Delete the old random number in the access memory 53 Step 844) Send the random number update message to the random number generator 27
(step 845), and thereafter the host computer 2
6, a new random number is used (step 846).

When the random number generator 27 receives a random number update message from the terminal 28 (step 847), it counts the number of received update messages (step 848).
After the update timer expires, stop receiving update messages (
step 849).

The value of the update counter is compared with the total number of terminals in the edge unregistered table 33 (step 850), and if the value of the update counter and the total number of terminals match, the process proceeds to step 858 in FIG. 8(e). , if they do not match, the confirmation message is retransmitted to the terminal 28 that has not returned the random number update message (step 852).

Next, the retransmission counter of the terminal that retransmitted is incremented by 1 (step 853).

(d) Refer to the diagram. If the value of the terminal-side retransmission counter does not match the preset retransmission limit, the process returns to step 852 in FIG. A setting is made to the effect that the transmission has been canceled (step 855). Edge unregistered table 33
If there is a terminal that has issued a retransmission request, the process returns to step 852 in FIG. 8(d); otherwise, in step 858, Return to step 801 of a).

FIGS. 9(a) and 9(b) are flowcharts showing detailed processing at the time of an access request. Note that FIGS. 3 to 5 will be referred to as appropriate.

When the user inputs a command to request connection to the host computer 26 at terminal A (step 901), terminal A retrieves a random number from the access memory 53 (step 902), and includes this random number and the terminal in a connection request message. An identification number is added and sent to the transmitter/receiver 54 (step 903).

The transmitting/receiving unit 54 transmits the message to the communication network 21 along with the destination of the host computer 26 (step 904).
). The message is delivered to the host computer 26 via the communication network 21 (step 905).

In the host computer 26 that received this message, the random number in the message is sent to the confirmation unit 44 (step 906), and the new random number (new random number and old random number in a predetermined case) stored in the reference memory 43 is sent. Check section 44
(Step 907), the confirmation unit 44 compares these random numbers (Step 908), and if they do not match, the process ends without permitting access (Step 90).
9). If they match, the line/connection setting section 42 is notified (step 910), and a line setting request or connection setting request is sent to the communication network 21 via the transmitting/receiving section 54 (step 911). Based on this request, the communication network 21 connects the host computer 26 and the corresponding terminal A.
A line or connection is set up with (step 912).

Refer to FIG. 9(b). At terminal A, when the user enters the ID number and password manually, the ID number and password are added to the access request message,
The message is sent to host computer 26 (step 913). Host computer 2 that received this
6, in step 914, it is determined whether the ID number is registered or not, and if it is not registered, the process is terminated without permitting the access request. If the password is registered, in step 915 the password is
It is determined whether the number corresponds to the number, and if the number does not correspond, the process is terminated without permitting the access request. If it is compatible, access to the terminal is permitted (step 916).

According to this embodiment, only the terminal 28 that receives the random number from the random number generator 27 and holds it, that is, the terminal 28 that has registered to subscribe to the system, can set up a line or connection with the host computer 26. can receive,
Even if a so-called "backer" or the like obtains your ID number and password, the host computer 26 will not request access unless you are using the registered terminal 28, thus improving its security. I can do it.

In addition, since the time required to compare and match the random number sent from the terminal 28 and the random number held by the terminal is very short,
It is highly efficient compared to the methods described in the prior art. Furthermore, since random number matching is automatically performed, there is no need to increase the operating burden on the user.

In the description of this embodiment, the random number generator 27 is independently connected to the communication network 21, but the random number generator 27 may be provided as a function of the host computer 26. Furthermore, in this embodiment, the random number generator 2
7 is designed to be generated periodically, but the present invention is not limited to this. For example, the random number generation timer 31 of the random number generation device 27 can be generated by the host computer 26.
If the system is configured to be controlled by a computer or other control device, and the timing of random number generation is made irregular, safety can be further improved.

Effects of the Invention As described in detail above, the present invention provides a system in which a random number is periodically or irregularly sent to terminals registered to subscribe to the system and the host convenience store 91, and a terminal desiring access receives this random number. The random number is sent to the host computer, the host computer determines whether or not this random number is valid, and access is only permitted if it is valid, which eliminates the long verification process that was pointed out as a problem with the conventional method. This has the effect that it is possible to effectively prevent unauthorized access while solving problems such as time consuming or heavy memory load on the host computer.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is a system configuration diagram of an embodiment of the invention, Fig. 3 is a functional configuration diagram of a random number generator in an embodiment of the invention, and Fig. 4 is a host diagram of the embodiment of the invention. FIG. 5 is a functional configuration diagram of a subscriber terminal in an embodiment of the present invention; FIGS. 6(a) to (c) are explanatory diagrams of random number setting in an embodiment of the present invention; FIG. 7(a) ~(c) are explanatory diagrams of validity confirmation in the embodiment of the present invention, Figures 8(a) to (e) are flowcharts showing detailed processing when setting random numbers in the embodiment of the present invention, and Figure 9(a) ,
(b) is a flowchart showing detailed processing at the time of an access request in the embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Host computer, 2...Subscribing terminal, 3...Non-subscribing terminal, 4...Communication network, 5...Random number generation means. Principle diagram Figure 1 Figure (b) Figure

Claims (1)

[Scope of Claims] 1. Accessed via a communication network (14) from a plurality of subscriber terminals (12) that have subscribed to the host computer (11) and non-subscriber terminals (13) that have not subscribed to the host computer (11). In some cases, unauthorized access prevention methods for computer systems include random number generation means (15) that generates random numbers at regular or irregular time intervals and sends the random numbers to a host computer (11) and a subscriber terminal (12). In preparation, when the subscriber terminal (12) requests access to the host computer (11), it sends a random number it owns to the host computer (11), and
An unauthorized access prevention method characterized in that a random number sent from the subscriber terminal (12) is compared with a random number held by the subscriber terminal, and access is permitted only if they match. 2. In the unauthorized access prevention method according to claim 1, the host computer (11) compares the previously sent random number with the previously sent random number from when the random number is sent from the random number generating means (15) until a predetermined period of time has elapsed. An unauthorized access prevention method characterized in that access is permitted if the random number sent from the subscriber terminal (12) matches one of the random numbers sent this time.