JP2004096178A - Encryption communication method and apparatus thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the improvement of security in performing IPsec protocol communication is sought. <P>SOLUTION: Upon receiving a communication request by IPsec, an SA (security association) control section confirms the presence or absence of an SA by referring to an SAD (security association database) (S10). If the SA is not present (N in S10), the SA control section confirms the presence or absence of a saved SA by referring to a save SA holding section (S12). When the saved SA is present (Y in S12), a user is authenticated by a password set when the SA is saved (S14). If the user is authenticated (Y in S14), the saved SA is sent back to the SAD (S16), an IPsec processing section executes communication by IPsec based on the SA (S18). <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technology for performing encrypted communication on a network.
[0002]
[Prior art]
IPsec (IP Security Protocol) is a security technology that can be used for general purposes in a network environment using TCP / IP (Transmission Control Protocol / Internet Protocol). This IPsec is for encrypting and authenticating communication packets using IP (Internet Protocol), and is one of the key technologies when constructing a VPN (Virtual Private Network) in the IPv6 standard. If security protocols such as SSL (Secure Sockets Layer) and S / MIME (Secure / Multipurpose Internet Mail Extension) are used, TCP / IP communication security can be ensured by a specific application, but these are used. Requires individual settings for each corresponding application. For example, when various application protocols are used in communication between bases in a company, security settings must be repeatedly set for each application, which requires a very complicated operation. Further, when a plurality of computers communicate with each other so as to form a network, even maintaining and managing the settings can be a heavy burden.
[0003]
IPsec has been devised to solve such a problem. In this protocol, the application itself does not have a security function separately, but the communication protocol itself provides the security function. According to IPsec, security setting for each application becomes unnecessary. That is, security functions can be integrated.
[0004]
This IPsec is a protocol for transmitting and receiving an encrypted packet on a communication path having both ends of a communication device having an IP address. When the encrypted communication based on IPsec is started, information necessary for encryption by the communication devices that are the communication end points, specifically, the type of the encryption algorithm, keys for encryption and decryption, and the like are determined by negotiation. You. The information required for this encrypted communication is called a security association (hereinafter, simply abbreviated as “SA”), and is provided at a communication end point with a security association database (hereinafter, also abbreviated as “SAD”). Is held. When the SA is created, authentication of the user using the communication device is performed. In the SA, the lifetime is set by the total number of communication bytes or time. When the SA reaches the set lifetime, a new SA is created, and at the same time, the user is re-authenticated.
[0005]
In order to prevent the use of an unauthorized user, that is, to prevent a case in which a malicious user uses a device of a valid user without permission, it is necessary to frequently update the SA and authenticate the user. However, if the SA is updated frequently, the load on the system increases, and the performance of the network environment may decrease. Further, if the mechanism of IPsec itself is changed, compatibility with the existing IPsec system cannot be maintained and encrypted communication cannot be performed.
[0006]
The present invention has been made in view of such a situation, and an object of the present invention is to provide a technique for improving security of communication in communication using IP. Still another object is to provide a technique for controlling an SA, which enables a user to be authenticated at a frequency that does not significantly lower the performance of a communication device without changing the basic mechanism of IPsec.
[0007]
[Means for Solving the Problems]
One embodiment of the present invention relates to an encrypted communication method. According to this method, when network communication is performed by encrypting a communication packet using IP, information set for encryption processing and decryption processing is transmitted before the expiration date of the information. The information is invalidated by being moved from a place where it originally exists to a place where it can be returned.
[0008]
By performing encryption processing on the IP layer, it is not necessary to authenticate each application when performing network communication. However, once authenticated and communication establishment is maintained, the user is recognized as a valid user until the next authentication. That is, it becomes possible for an unauthorized user to communicate using an authenticated terminal. The information used for authentication has an expiration date set according to time or the amount of data used for communication. By shortening the update interval, the security level increases. However, at the time of the update, the load on the communication system may increase, and the performance of the communication device may decrease. Therefore, when the user logs off or shuts down, the information used for authentication is forcibly invalidated by deleting or moving the information even before the expiration date. As a result, authentication is required the next time the communication device is used, and as a result, security is improved while suppressing an increase in the load on the communication environment.
[0009]
Another embodiment of the present invention also relates to an encrypted communication method. In this method, when performing encrypted communication according to a security architecture related to IP, an SA set as information for encryption processing and decryption processing is set before an expiration date set in advance for the SA. It is deleted or moved from the place where the information should originally exist and invalidated. The SA is invalidated when the user stops or stops communication by the communication method or when the terminal to be used is logged off or shut down. The SA may be invalidated when no input is made to the terminal used by the user for a predetermined time or when a predetermined application for communication is monitored and its use is completed.
[0010]
Another embodiment of the present invention relates to an encrypted communication device. This apparatus performs an IPsec processing unit that performs predetermined processing on a communication packet using an IP according to a security architecture related to the IP and encrypts and decrypts the packet, and a policy that manages a processing method applied to the IP packet based on the SA. It has management and an SA control unit that invalidates the SA before the original expiration date.
[0011]
It is to be noted that any combination of the above-described components and any conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, and the like are also effective as embodiments of the present invention.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present embodiment, in network communication using IPsec, when a predetermined condition is satisfied, the SA used for the encrypted communication processing is deleted or saved before the life set according to the standard. When saving an SA, simple authentication information of a user used to restore the SA is set. As a means of the simple authentication, for example, there are a password, use of an IC card individually held by a user, fingerprint authentication, and the like. When a legitimate user issues a communication request by IPsec, it is checked whether the SA previously used by the user is in a save state, and if there is a saved SA (hereinafter, also referred to as “evacuated SA”), The evacuation SA is returned to the SAD where the SA should be held, and is used again. When the save SA is returned to the SAD, the user is authenticated by the simple authentication set when the SA is saved. In the following description, a password is used as simple authentication, but the present invention is not limited to this.
[0013]
Conditions for invalidating, that is, deleting or saving the SA include, for example, termination of the virtual terminal, logoff of the user, and shutdown of the operation system. Furthermore, the communication may be stopped, or there may be no input to the terminal for a predetermined time, or an application that starts network communication may be monitored and the application may be terminated. These conditions are set in advance by the user.
[0014]
FIG. 1 shows a configuration of a network system 10 including an IPsec device 20 according to the present embodiment. Each user terminal 12 is connected to the Internet 18 via an IPsec device 20, and implements encrypted communication based on the IPsec protocol.
[0015]
FIG. 2 is a block diagram illustrating a configuration of the IPsec device 20. The IPsec device 20 includes an IPsec processing unit 40, a policy management unit 42, a database unit 60, an SA control unit 50, and a simple user authentication unit 52. Further, the database unit 60 includes the SAD 44, the SPD 46, and the evacuation SA holding unit 48. Here, the IPsec device 20 is a general term for an IPsec host, which is a host on which IPsec is implemented, and a security gateway, which is a relay device on which IPsec is implemented. Therefore, there are cases where the user terminal 12 and the IPsec device 20 are configured as the same device. The feature of this embodiment is the SA control unit 50 and the simple user authentication unit 52. Other components have a configuration and a function conforming to the IPsec standard, so that they are briefly described, and some components are appropriately omitted.
[0016]
The IPsec processing unit 40 inquires of the policy management unit 42 about the processing method of the IP packet, and performs a process on the IP packet according to a response from the policy management unit 42. The policy management unit 42 refers to the SAD 44 and the SPD 46 to notify the IPsec processing unit 40 of the processing method of the IP packet to be processed.
[0017]
The SAD 44 stores an SA that is a connection protected by the IPsec security protocol. The SPD 46 holds a security policy describing a method of IPsec processing. The SPD 46 includes an output SPD that holds a security policy for an output packet, and an output SPD that holds a security policy for an input packet. The evacuation SA holding unit 48 holds the SA that the SA control unit 50 has moved by the processing described later.
[0018]
The SA control unit 50 monitors the IPsec processing unit 40, and when an IPsec communication request occurs, refers to the SAD 44 to check whether there is an SA to be applied to the IP packet to be processed by the IPsec processing unit 40. . If there is an SA, it instructs the IPsec processing unit 40 to perform general IPsec communication. On the other hand, if the SA does not exist, it refers to the save SA holding unit 48 and checks whether the save SA exists. If there is an evacuation SA to be returned to the SAD 44, the SA control unit 50 returns the evacuation SA, and thereafter notifies the IPsec processing unit 40 to perform IPsec communication based on the SA. If there is no evacuation SA to be returned, it notifies the IPsec processing unit 40 to create a new SA in accordance with general IPsec processing. In addition, the SA control unit 50 deletes the SA or moves it to the evacuation SA holding unit 48 and invalidates the SA before the expiration date of the SA with a predetermined condition as a trigger. In addition, the SA control unit 50 sets the conditions in advance by the input of the user.
[0019]
The user simple authentication unit 52 sets a password when the SA control unit 50 saves the SA, and prompts the user to input a password when the saved SA is returned to the SAD 44, thereby performing simple authentication of the user.
[0020]
The operation of the above configuration will be described with reference to the flowcharts shown in FIGS. FIG. 3 is a flowchart showing a process in the IPsec device 20 when communication by the IPsec protocol is started.
[0021]
When there is a communication request by IPsec, the SA control unit 50 checks the presence or absence of the SA by referring to the SAD 44 (S10). If an SA exists (Y in S10), communication by IPsec is performed based on the SA (S18). When there is no SA (N in S10), the SA control unit 50 refers to the save SA holding unit 48 and checks whether or not there is a save SA (S12). If there is an evacuation SA (Y in S12), the user simple authentication unit 52 performs simple authentication of the user using the password set when the SA is evacuated (S14). When the user is authenticated (Y in S14), the SA control unit 50 returns the evacuation SA to the SAD 44 (S16). Subsequently, the IPsec processing unit 40 executes communication by IPsec based on the SA (S18). On the other hand, if the evacuation SA does not exist (N in S12), and if the evacuation SA exists and the user is not authenticated when returning it to the SAD 44 (N in S14), the IPsec standard is used. Creation of a new SA (S20) and user authentication are performed (S22), and communication based on IPsec is executed based on the created SA (S18). Of course, if the user authentication is not performed in S22, the communication by IPsec is not performed, and the communication that is not encrypted is performed, or the communication itself is not performed.
[0022]
FIG. 4 is a flowchart illustrating a process of deleting or saving an existing SA. This process is performed when a predetermined event such as a log-off of the user or a shutdown of the operation system occurs.
[0023]
When a predetermined event occurs, the SA control unit 50 confirms whether or not a condition for invalidating the SA by deleting or saving the SA is satisfied (S52). If the condition is not satisfied (N in S52), this process ends. If the condition is satisfied (Y in S52), the SA control unit 50 deletes or saves the SA by setting in advance (S54). In the case of deletion (S54-1), the SA control unit 50 deletes the SA (S56), invalidates the SA (S60), and ends the processing. In the case of evacuation (S54-2), the SA control unit 50 moves the SA to the evacuation SA holding unit 48, and at this time, the user simple authentication unit 52 sets the user authentication password to be used the next time the SA is returned to the SAD. The setting is made (S58), the SA is invalidated (S60), and the process ends.
[0024]
The above-described configuration can be realized in terms of hardware by a CPU, a memory, or another LSI of an arbitrary computer, and is realized in terms of software by a program or the like loaded in the memory. It depicts the functional blocks that are realized. Therefore, it is understood by those skilled in the art that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.
[0025]
As described above, according to the present invention, in communication using IP, security at the IP layer level is improved. From another viewpoint, IPsec and SA are controlled without changing the basic mechanism of IPsec, easily and without significantly lowering the performance of the user terminal 12, thereby improving the security of communication using IPsec.
[0026]
The present invention has been described based on some embodiments. These embodiments are exemplifications, and it is understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. By the way.
【The invention's effect】
According to the present invention, in communication using IP, an improvement in security at an IP layer level is expected.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a network system including an IPsec device according to an embodiment.
FIG. 2 is a block diagram showing a configuration of an IPsec device according to the embodiment.
FIG. 3 is a flowchart showing a process in an IPsec device when communication according to the IPsec protocol is started.
FIG. 4 is a flowchart illustrating a process of deleting or saving a currently used SA.
[Explanation of symbols]
12 user terminal, 18 Internet, 20 IPsec equipment, 40 IPsec processing section, 42 policy management section, 44 SAD, 48 evacuation SA holding section, 50 SA control section, 52 simple user authentication section.

Claims (11)

When performing network communication by encrypting a communication packet using the Internet protocol, information set for encryption processing and decryption processing must be stored before the expiration date of the information. An encrypted communication method, wherein the information is invalidated by being moved from a place to a place where it can be returned. When performing encrypted communication according to the security architecture related to the Internet protocol, the security association set as information for encryption processing and decryption processing is deleted before the expiration date set in advance for the security association. Alternatively, the security association is invalidated by moving from a place where the security association should originally exist. When starting the encrypted communication, confirming the presence or absence of the invalidated security association,
When the existence of the invalidated security association is confirmed, under a predetermined authentication, a step of validating the invalidated security association,
The encrypted communication method according to claim 2, further comprising: The encrypted communication method according to claim 3, wherein the predetermined authentication is performed by a simple authentication unit. The encrypted communication method according to any one of claims 2 to 4, wherein the security association is invalidated when the user ends communication by the communication method. An IPsec processing unit that performs predetermined processing on a communication packet using the Internet protocol in accordance with a security architecture related to the Internet protocol, and performs encryption and decryption;
Policy management that manages the processing method applied to IP packets based on security associations;
An SA control unit for invalidating the security association before an original expiration date;
An encrypted communication device comprising: 7. The encrypted communication apparatus according to claim 6, wherein the SA control unit invalidates the security association by deleting the security association or moving the security association from a security association database where the security association is originally held. When starting the encrypted communication according to the security architecture related to the Internet protocol, the SA control unit checks whether there is a security association that has been invalidated by being moved from the place where it is originally held, and confirms the existence. 8. The encrypted communication device according to claim 7, wherein when the security association is made, the security association is returned to the security association database. When the security association is moved to be invalidated, user simple authentication information used when returning the security association to the security association database is set, and when returning the security association to the security association database, the user is notified of the user. The encrypted communication device according to claim 8, further comprising a user simple authentication unit that performs authentication based on the simple authentication information. 10. The encrypted communication device according to claim 6, wherein the security association control unit receives a condition for invalidating the security association from a user. A function of performing processing and encrypting and decrypting communication packets using the Internet protocol according to a security architecture related to the Internet protocol,
A function of managing a processing method applied to the communication packet based on a security association used as information for encryption processing and decryption processing,
A computer program for causing a computer to execute a function of invalidating the security association before an original expiration date.

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