JP2006180561A - Wlan-session management techniques with secure key and logoff - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for improving the security of a mobile terminal in a WLAN environment, by installing two shared secrets, in place of an initial session key and a single shared secret, in both of a wireless user apparatus and a WLAN access point during the user authentication phase. <P>SOLUTION: One of these shared secrets is used as the initial session key, and the other is used as secure seed. Since initial authentication is secure, these two keys will not be recognized by hackers. Although the initial session key can be cracked eventually by hackers, since secure seed will not be used in any of non-secure communication, and it will be maintained as secure, as is. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus and method for providing a secure communication session in a local area network, and more particularly to an apparatus and method for providing a secure communication session with a mobile terminal in a WLAN with periodic key update and secure logoff. About.

  The background of the present invention is a family of wireless local area networks using an IEEE 802.1x architecture with access points that provide access to mobile devices and other networks such as the global network such as the Internet and wired local area networks. . Advances in WLAN technology have made it publicly available in rest areas, coffee shops, libraries and similar public facilities (“hot spots”). Currently, public WLANs provide mobile communication devices with user access to data networks such as corporate intranets, or public data networks such as the Internet, peer-to-peer communications and live wireless TV broadcasting. The relatively low cost of implementing and operating a public WLAN and the high bandwidth available (usually 10 Mb / sec or more) makes the public WLAN an ideal access mechanism, so that users of mobile wireless communication devices can Packets can be exchanged with external entities. However, as described below, such published implementations compromise security in the absence of appropriate means for identification and authentication.

  When a user attempts to access a service in the area covered by a public WLAN, the WLAN first authenticates and grants user access before granting network access. After authentication, the public WLAN opens a secure data channel to the mobile communication device to protect the confidentiality of data passing between the WLAN and its device. Currently, many manufacturers of WLAN devices employ the IEEE 802.1x protocol for the devices being implemented. Therefore, the dominant authentication mechanism for WLAN uses this standard. Unfortunately, the IEEE 802.1x protocol is designed with private LAN access as its usage model. Therefore, the IEEE 802.1x protocol cannot provide certain features that improve security in public WLAN environments.

  In an authentication method based on a web browser, the mobile terminal uses HTTPS (Hyper Text Transfer Protocol Secured Sockets) to ensure that someone in the path between the mobile terminal and the authentication server cannot infringe or steal the confidential information of the user. ) To communicate with the authentication server. However, the only information that the authentication server relates to the mobile terminal is the IP address.

  Once the user is authenticated by the WLAN, a secure session key is established and shared between the user and the WLAN. All subsequent communications are encrypted using this session key. In order to avoid security attacks, for example attacks that look for security holes in the IEEE 802.11 WEP cryptographic protocol and to ensure strong security, the session key needs to be updated periodically. In practice, if the initial session key is used as a WEP (Wired Equivalent Privacy) key, after a specific number of telecommunications switches use the WEP key between the wireless user and the WLAN access point, the hacker will use that key. Can break through. In IEEE 802.1x, the protocol used for secure access control in the WLAN depends on the authentication server when the session key is updated. In essence, each time the key is updated, the user needs to go through an authentication step similar to the initial authentication. This approach is inefficient or impossible in some applications. While WLAN technology can benefit from the way in which a user is authenticated and a session key is established, future keys no longer require the involvement of an authentication server.

  Furthermore, management information, especially applications that handle logoff requests, typically require security against hacking. However, in IEEE 802.1x, such information is freely transmitted and therefore by leaving a mobile terminal susceptible to attacks from hackers, even if a hacker does not have the session key, The authenticated user will be logged off. Such WLAN technology can benefit from methods provided for logoff requests or encryption key updates for requests that are additionally encrypted with a session key.

  A method for providing a secure communication session between a terminal and a communication network by using a session key for encrypting communication between the terminal and the communication network, the session key of the communication network There is a need for a method that can be obtained from a set of keys including a secure key stored in an access point and a terminal. A secure key can also be used in providing a secure logoff mechanism.

  The present invention now replaces the installation of one shared secret, called the initial session key at both the WLAN AP and the wireless user equipment, during the user authentication phase of installing two shared keys. A method for improving terminal security is provided. One of the shared keys is used as an initial session key, and the other shared key is used as a secure seed. Since the initial authenticated communication is secure, once two secure keys are established, it is practically impossible for a hacker to break through this form of protection. The initial session key may eventually be broken by a hacker, but the secure seed is always used to remain secure because it is not used in any non-secure communication.

  Embodiments of the present invention include a process in which a new key is created and updated between the WLAN access point and the building terminal during the key update. Instead of using this new key directly, the access point and mobile terminal use this new key with a secure seed to create a new session key. For example, a new session key can be created by associating the new key with a secure seed, and thus a one-way such as Message Digest 5 (MD5) hash algorithm for creating a fixed string. Compute the hash function of Since hackers do not have a secure seed, even if they can break through an old session key, they will not succeed in obtaining a new session key.

  Embodiments of the present invention also include a process in which the mobile terminal is kept secure to prevent hackers from logging off the authenticated mobile terminal during session logoff. The scheme based on IEEE 802.1x does not give a secure logoff because the logoff request is put in an unencrypted frame. However, in the embodiment of the present invention, the mobile terminal transmits an encryption logoff request accompanying the secure seed. Therefore, even if a hacker breaks out of the session key, the secure seed appears in the logoff request and is no longer valid (a new secure seed needs to be negotiated every time the user logs in) Authenticated user logoff is not possible, so even if the old secure seed is broken by hackers. No further damage is caused.

  An embodiment of the present invention is also a method for providing a secure communication session between a mobile terminal and a wireless local access network (WLAN): creating a first secure key and a second secure key; Transmitting a first secure key and a second secure key using a secure communication method, wherein the first secure key and the second secure key are stored in a mobile terminal used during a secure communication session; Encrypting and transmitting data to the mobile terminal using the session key of the mobile station and receiving and decrypting data received from the mobile terminal using the current session key, comprising: One secure key is used as the current session key; and during the subsequent communication between the WLAN and the mobile terminal Including methods with; the use of a subsequent session key as the session key, using the second secure key, the step of periodically create a subsequent session keys.

  The present invention also provides an apparatus for providing a secure communication session between a mobile terminal and a WLAN, the means for generating a first secure key and a second secure key, and a first secure key for the mobile terminal. And a means for transmitting the second secure key. The mobile terminal stores a first secure key and a second secure key for decrypting subsequently received data. In WLAN, the means encrypts data to the mobile terminal using the current session key and transmits the data to the terminal. In the WLAN, the means for periodically creating the subsequent session key uses the subsequent session key as the current session key during communication between the WLAN and the mobile terminal, and uses the second secure key.

  The invention can be best understood by reading the following detailed description with reference to the accompanying drawings. The various features of the drawings are not fully shown. In contrast, the various features are arbitrarily expanded or reduced for clarity.

  In the illustrative figures, the circuits, associated blocks and arrows represent the functions of the process according to the present invention that can be implemented as electrical circuits and associated wiring and data bushes that transport electrical signals. ing. Alternatively, one or more associated arrows can represent communication (eg, data flow) between software routines, particularly when the method or apparatus of the present invention is implemented as a digital process.

According to FIG. 1, one or more mobile terminals represented by 140 _{1 to} 140 _n are associated with one or more operators 150 _1-n such as an authentication server 150n and a firewall 122, via the access point 130 _n, to communicate with the local computer 120. Communications from terminals 1401-n typically access the secure database or other resources utilizing the Internet 110 and associated communication paths 154 and 152 that require a high degree of security against unauthorized entities such as hackers. Need.

As further shown in FIG. 1, the IEEE 802.1x architecture covers several components and services that interact to provide transparent station mobility for higher layers of the network stack. ing. The IEEE 802.1x network defines stations such as access points 130 _1-n and mobile terminals 140 _1-n as component communications in the wireless medium 124, and MAC (medium access control) 138 _1-n , corresponding. It has the functionality of the IEEE 802.1x protocol, which is a PHY (physical layer) (not shown) and a connection 127 to a wireless medium. Typically, IEEE 802.1x functionality is implemented in the wireless media, network access or interface card hardware and software. The present invention provides one or more access points 130 _1-n that are compatible with the IEEE 802.1x WLAN MAC layer for downlink traffic (ie, from an authentication server to a mobile terminal such as a laptop). A method for implementing identification means in a communication system that can participate in the authentication of a wireless mobile device 140 _1-n , a local or back-end server 120 and an authentication server 150 is provided.

In accordance with the principles of the present invention, the access 160 allows each mobile terminal 140 _1-n to securely access the WLAN 115 by authenticating both the communication stream according to the IEEE 802.1x protocol and the mobile terminal itself. To. The manner in which access 160 allows such access can best be understood by referring to FIG. 1 in conjunction with FIG.

A series of long-term interactions between mobile wireless communication devices, eg, mobile terminal 140 _n , public WLAN 115, local web server 120 and authentication server 150, are described under the IEEE 802.1x protocol conventions. It is, the access point 130 _n in FIG. 1, maintains control ports and uncontrolled ports access point to exchange mobile terminal 140 _1-n and information. Control port maintained by the access point 130 _n is, when flowing between the local server 120 and the mobile terminal 140 _1-n are data traffic, unauthenticated information, such as data traffic passing through the access point 130 _n To serve as an entrance passage for. Normally, the access points 130 _1-n keep their respective control ports closed according to the IEEE 802.1x protocol until communicated for authentication of the appropriate mobile terminal 140 _1-n . The access point 130 _1-n always maintains each uncontrolled port open to allow the mobile terminal 140 _1-n to exchange authentication data with the authentication server 150.

More particularly, referring to FIG. 2, the method according to the present invention for improving the security of a mobile terminal 140 _n in a WLAN environment is described in the WLAN access point 130 _n and mobile terminal 140 _n during the user authentication phase. In both cases, two shared secrets are installed instead of one shared secret. One of those shared secrets is used as an initial session key, and the other shared secret is used as a secure seed. Since the initial authentication is secure, those two keys are not known to hackers. In order to create and distribute such keys, the keys can be created and distributed to mobile terminals and WLANs using known methods, for example using an authentication server. Is possible. Although the initial session key can eventually be broken by hackers, the secure seed is not used in any non-secure communication and therefore remains secure. In particular, the method of the present invention processes a web request from mobile terminal 140 _n by access point 130 _n to embed session ID 215.

Referring to FIG. 2, the method according to the present invention, during user authentication phase, to improve the security of the mobile terminal 140 _n in both the WLAN access point 130 _n and the mobile terminal 140 _n, whereby the first secret It is the first session key and the following key is used as a secure seed.

In accordance with the principles of the present invention, there is provided a respective mobile communication device, for example, that each of the devices 140 ₁ to 140 _n to access secure to the WLAN115 provide authentication of both the traffic generated from the device itself and apparatus Provide technology to be possible. In the authentication technique used in FIG. 2, a series of communications existing over a long period between the mobile terminal 140 _n , the access point 130 _n and the authentication server 150 is shown. In order to initiate secure access, the mobile terminal 140 _n sends a request for access to the access point 130 _n in step 200 of FIG. Actually, the mobile terminal 140 _n starts an access request as an HTTPS access request obtained by a browser software program (not shown) executed by the mobile terminal 140 _n . In response to the access request, the access point 130 _n redirects the browser software at the mobile terminal 140 _n to the local welcome page at the access point 130 _{n at} step 202.

Following step 202, mobile terminal 140 _n initiates an authentication sequence in step 204 by querying access point 130 _n for the identity of the appropriate authentication server. In response, the access point 130 _n determines the identity of the appropriate authentication server (eg, server 150) at step 206, and then, at step 208, the browser software at the mobile terminal 140 _n is sent to that server via an HTTP command. Orient. Here, if in step 208 the identity of the authentication server 150 is received, the mobile terminal 140 _n then sends its user proof to the server in step 210 of FIG.

Upon receipt of the user proof from mobile terminal 140 _n , authentication server 150 determines whether mobile terminal 140 _n has a valid user in step 212. If yes, the authentication server 150 responds to the mobile terminal 140 _n in step 214 with a WEP (Wired Equivalent Privacy) encryption key. The device calls the ActiveX command of ActiveX control by the device browser software. An ActiveX control is essentially an executable program that can be embedded in a web page. Many software browser programs, such as Microsoft Internet Explorer, have the ability to call embedded ActiveX controls that can be downloaded from a remote server (eg, authentication server 150) and display such web pages. The execution of ActiveX control is limited by the security mechanism built into the browser software. In practice, most browser programs have several different selectable security levels. At the lowest level, any ActiveX control from the web can be invoked without restriction. At the highest level, there is no ActiveX control that can be called from browser software.

After authentication and authorization, the method according to the present invention comprises a procedure of creating a first key and distributing a new key to the access point 130 _n and the mobile terminal 140 _n in step 217. A second key called secure seed 123 is distributed to access points 130 _n and mobile terminals 140 _n . Thereafter, the access point 130 _n and the mobile terminal 140 _n communicate using the first key as a session in order to encrypt data. Thereafter, the access point 130 _n and the mobile terminal 140 _n use the secure seed 123 and the key 119 to periodically create a new session key, whereby the new session key is then transferred to the mobile terminal and the access point. Used for subsequent communication between. The second key is always stored and maintained as a secret at the access point and the mobile terminal during the communication session so that the hacker cannot determine the second key. To make it easier to manage combined keys, such as creating a new session key and binding that new session key to a secure seed prior to using it for security Technology can be used. Once the combined session key and secure key are combined, the process can calculate a hash algorithm for the combined new session key and secure seed and create a fixed string for further transmission. is there.

Method for improving the security of a mobile terminal in WLAN environment consists of the stage of the mobile terminal 140 _n to transmit the encrypted logoff request associated with the secure seed as secure seeds appear at logoff request during the session log off. As shown in FIG. 3, during the session log-off, in order to hacker does not log off the mobile terminal 140 _n authenticated, the mobile terminal 140 _n is maintained secure. Schemes based on IEEE 802.1x cannot provide secure logoff because logoff requests do not enter unencrypted frames. However, in the embodiment of the present invention, the mobile terminal 140 _n transmits the encrypted logoff request 228 with the secure seed 123. Therefore, even if the hacker breaks out of the session key, logoff of the user authenticated at the mobile terminal 140 _n is not possible because the secure seed 123 appears in the logoff request 228, and every time the user logs in Secure seeds are no longer used because they need to be negotiated.

In Figure 4, shows a device for secure communication session between the mobile terminal 140 _n and WLAN. The access point 130 _n includes means 410 for generating the first secure key and the second secure key, and means 420 for transmitting the first secure key 119 and the second secure key 123 to the mobile terminal 140 _n . Is done. The mobile terminal 140 _n receives the first secure key 119 and the second secure key 123 and stores the keys in the register 430 for use during the secure communication session. Access point 130 _n includes means 415 for encrypting data and means 420 for transmitting data to mobile terminal 140 _n over WLAN 115 using the current session key. Mobile terminal 140 _n includes means 450 for receiving and means 435 for decrypting data received from access point 130 _n using current session key 119, the first secure key being initially Used as the current session key 119. The access point 130 _n periodically creates a subsequent session key using the subsequent session key as the current session key and the second secure key during subsequent communication between the WLAN 115 and the mobile terminal 140 _n. Means 425.

  The described embodiments of the invention are to be understood as merely preferred embodiments. Various changes may be made in the function and construction of the components without departing from the scope and spirit of the invention as defined in the appended claims, equivalent means being shown in the figures and Can be substituted for the means described in, and certain features can be used independently of other features.

1 is a block diagram of a communication system for implementing a method in accordance with the principles of the present invention for authenticating a mobile wireless communication device. FIG. 3 is a flow diagram of a method for establishing two secure keys of the present invention. FIG. 5 is a flow diagram of a method for establishing a secure logoff technique in the present invention. It is a block diagram of the apparatus for implementing this invention.

Explanation of symbols

110 Internet 115 WLAN
119 Key 120 Local computer 122 Firewall 123 Secure seed 130 Access point 138 Medium access control 140 Mobile terminal 150 Authentication server 152 Related communication path 154 Related communication path 160 Access 215 Session ID
410 means for generating first secure key and second secure key 415 means for encrypting data 420 transmitter 425 means for periodically generating session key 430 register 435 means for decrypting data 450 receiver

Claims (29)

A method for providing a secure communication session using a user terminal in a communication network comprising:
Receiving a secure key and a secure seed by a user terminal using a secure communication method, wherein the secure key and the secure seed are stored in the user terminal for use during the secure communication session Appropriate to the stage;
Encrypting and transmitting data by the user terminal using a current session key and decrypting data received by the user terminal using the current session key, the secure key comprising: Initially used as the current session key; and periodically receiving subsequent session keys by the user terminal and using the subsequent session key as the current session key during subsequent communication;
A method comprising:   The method according to claim 1, wherein the user terminal is a mobile terminal.   The method of claim 1, wherein the communication network is a wireless network.   4. The method according to claim 3, wherein the wireless network is a wireless local area network.   The method of claim 1, wherein the user terminal sends a logoff message to terminate the secure communication session, the logoff message taking the form of an encrypted form and the secure communication session. A method further comprising the steps of having a key. A method for providing a secure communication session using a mobile terminal in a communication network comprising:
Receiving a secure key by the mobile terminal using a secure communication method, wherein the secure key is stored in the mobile terminal for use during the secure communication session;
Encrypting and transmitting data with the mobile terminal using a current session key and decrypting the data received by the mobile terminal with the current session key; and the secure communication session Sending a logoff message by the mobile terminal to terminate, wherein the logoff message takes the form of an encrypted form and has the secure key;
A method comprising:   The method of claim 6, wherein a secure seed is received by the mobile terminal, wherein the secure seed is stored in the mobile terminal for use during the secure communication session. The method further comprising:   8. The method of claim 7, further comprising the step of periodically creating a subsequent session key using the secure seed.   8. The method of claim 7, wherein periodically creating a subsequent session key using a combination of a new key and the secure seed, the new key being created using the secure key. , Further comprising steps.   10. The method of claim 9, wherein the step of periodically creating the subsequent session key comprises the steps of creating a subsequent session key by combining the new key and the secure seed, and the subsequent session And a procedure for executing a hash algorithm for creating a key. A method for providing a secure communication session using a mobile terminal in a communication network, comprising:
Receiving a secure key by the communication network using a secure communication method, wherein the secure key is stored in the communication network for use during the secure communication session;
Encrypting and transmitting data with the communication network using a current session key and decrypting data received by the communication network with the current session key, the secure key comprising: Initially used as the current session key; and periodically receiving a subsequent session key by the communication network and using the subsequent session key as the current session key during subsequent communication;
A method comprising:   12. The method of claim 11, further comprising receiving a logoff message by the communication network, wherein the logoff message takes the form of an encrypted form and has the secure key. A method characterized by that. A method for providing a secure communication session using a mobile terminal in a communication network, comprising:
Installing at least two shared secrets on the mobile terminal during a user authentication phase, whereby the first secret is an initial session key and the second secret is used as a secure seed to create a subsequent session key ;
A method comprising:   14. The method of claim 13, further comprising creating a new key and encrypting the new key with a current session key.   15. A method according to claim 14, wherein the step of creating a new key comprises the step of associating the current session key with the secure seed.   The method of claim 15, further comprising the step of creating a new session key by applying a hash algorithm to the bound result.   The method of claim 16, further comprising using the new session key in subsequent communications. A method for providing a secure communication session using a mobile terminal in a communication network, comprising:
Installing at least two shared secrets at the access point during the user authentication phase, whereby the first secret is an initial session key and the second secret is used as a secure seed to create a subsequent session key;
A method comprising:   The method of claim 18, further comprising creating a new key and encrypting the new key with a current session key.   The method of claim 19, wherein creating the new key comprises the step of associating the current session key with the secure seed.   21. The method of claim 20, further comprising the step of creating a new session key by applying a hash algorithm to the bound result.   The method of claim 21, further comprising using the new session key in subsequent communications. A method for providing a secure communication session between a mobile terminal and a communication network comprising:
Sending an encrypted logoff request with a secure seed as appearing in the logoff request by the mobile terminal during a session logoff;
A method comprising: An access point for providing a secure communication session between a mobile terminal and a communication network:
Means for transmitting a secure key and a secure seed using a secure communication method;
Means for encrypting data using the secure key; and means for periodically creating a session key that follows using the secure seed;
An access point characterized by comprising:   25. The access point according to claim 24, wherein the means for periodically creating a subsequent session key comprises means for creating a subsequent session key using a combination of a new key and the secure seed. The new key is created using the secure key.   25. The access point according to claim 24, wherein means for periodically creating a subsequent session key comprises: means for creating a subsequent session key by combining a new key and the secure seed; and An access point comprising means for executing a hash algorithm to create a subsequent session key. A terminal device for providing a secure communication session using a communication network comprising:
Means for receiving a secure key and a secure seed; and means for storing the secure key and the secure seed for use during the secure communication session;
Means for receiving data, and means for decrypting the data using a current session key during the secure communication session, the secure key initially being the current session key Means used for receiving and decoding said data;
Means for encrypting and transmitting data using said current session key; and means for creating a subsequent session key using said current session key and said secure seed, comprising: The subsequent session key is therefore used as said current session key for subsequent communication; means;
A terminal device comprising:   28. The terminal device according to claim 27, wherein the terminal device is configured by a mobile terminal, and the communication network is configured by a wireless local area network. An access point for providing a secure communication session between a mobile terminal and a communication network:
Means for transmitting a secure key and a secure seed, and means for storing the secure key and the secure seed for use during the secure communication session;
Means for encrypting data and means for transmitting data to the mobile terminal; and means for receiving data and data from the mobile terminal using a current session key during the secure communication session Means for decrypting, wherein the secure key is initially used as the current session key;
Means for generating a subsequent session key using said current session key and said secure seed, said subsequent session key being therefore used as said current session key for subsequent communication ,means;
An access point characterized by comprising:

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