JP2006520571A - WLAN session management technology using secure key and logoff - Google Patents

Abstract

The present invention provides a mobile terminal in a WLAN environment by installing an initial session key and two shared secrets instead of one shared secret at both the wireless user equipment and the WLAN access point during the user authentication phase. To provide a way to improve security. One of these shared secrets is used as an initial session key, and the other is used as a secure seed. Since the initial authentication is secure, these two keys are not recognized by hackers. Although the initial session key can eventually be broken by hackers, the secure seed remains secure because it is not used in any non-secure communication.

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 and impossible for 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 exchanged between a WLAN access point and a mobile terminal during a 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 the mobile terminal 140 _n , the authentication server 150 determines whether the mobile terminal 140 _n has an appropriate 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 on-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. In step 221, 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 121 225a so that the new session key is then accessed with the mobile terminal. Used for subsequent communication with points. 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 a combined key, 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 compute a hash algorithm for the combined new session key and secure seed and create a fixed string for further transmission. .

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. 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.

Claims (23)

A method for providing a secure communication session using a user terminal in a communication network comprising:
Transmitting a first secure key and a second secure key to a user terminal using a secure communication method, wherein the first secure key and the second secure key are used during the secure communication session; Suitable for storing at the user terminal;
Encrypt data for the user terminal using the current session key, send the data to the data terminal, receive data received from the user terminal using the current session key, and decrypt The first secure key is initially used as the current session key; and periodically creating a session key that continues using the second secure key; and Using the subsequent session key as the current session key during subsequent communication with the user terminal;
A method comprising: The method of claim 1, wherein:
Logging off the user terminal in response to an encryption logoff request from the user terminal with the second secure key;
The method further comprising:   The method of claim 1, wherein the step of periodically creating the subsequent session key comprises the step of creating the subsequent session key by combining the second secure key and the current session key; And a procedure for applying a hash algorithm. A method for providing a secure communication session using a mobile terminal in a wireless local access network (WLAN) comprising:
Transmitting a first secure key and a second secure key to a mobile terminal using a secure communication method, wherein the first secure key and the second secure key are used during the secure communication session; Suitable for storage at the mobile terminal;
Encrypts data to the mobile terminal using a current session key, transmits the data to the data terminal, receives data received from the mobile terminal using the current session key; Decrypting, wherein the first secure key is initially used as the current session key; and using the session key that follows as the current session key during subsequent communication using the mobile terminal; Periodically creating the subsequent session key using the second secure key;
A method comprising: 5. The method of claim 4, wherein the step of periodically creating the subsequent session key comprises:
A procedure for creating a subsequent session key using a combination of a new key and the second secure key, the new key being created using the first secure key. Feature method. 6. The method of claim 5, wherein the step of periodically creating the subsequent session key comprises:
The method comprises: a step of creating a session key that continues by combining the new key and the second secure key; and a step of executing a hash algorithm to create the subsequent session key. Method. A method for providing a secure communication session using a mobile terminal in a wireless local access network (WLAN) comprising:
Creating a secure key;
Transmitting the secure key to the mobile terminal using a secure communication method, wherein the secure key is stored at the mobile terminal for use during the secure communication session;
Encrypts data to the mobile terminal using a current session key, transmits the data to the data terminal, receives data received from the mobile terminal using the current session key; Decrypting; and terminating the secure communication session in response to receiving a logoff message from the mobile terminal, wherein the logoff message is in an encrypted form and includes the secure key;
A method comprising: A method for providing a secure communication session using a mobile terminal in a wireless local access network (WLAN) comprising:
Creating a first secure key and a second secure key;
Transmitting the first secure key and the second secure key to the WLAN using a secure communication method, wherein the first secure key and the second secure key are used for the WLAN during the secure communication session. Remembered in a stage;
Encrypting data for the WLAN using a current session key, transmitting the data to the data terminal, receiving and decrypting data received from the WLAN using the current session key Wherein the first secure key is initially used as the current session key; and periodically creating a subsequent session key using the second secure key and during subsequent communications using the mobile terminal Using the subsequent session key as the current session key;
A method comprising: 9. The method of claim 8, wherein the step of periodically creating the subsequent session key comprises:
A procedure for creating a subsequent session key using a combination of a new key and the second secure key, the new key being created using the first secure key. Feature method. The method of claim 9, wherein the step of periodically creating the subsequent session key comprises:
The method comprising the step of creating the subsequent session key by combining the new key and the second secure key and executing a hash algorithm to create the subsequent session key . A method for providing a secure communication session using a mobile terminal in a wireless local access network (WLAN) comprising:
Creating a secure key;
Transmitting the secure key to the WLAN using a secure communication method, wherein the secure key is stored in the WLAN for use during the secure communication session;
Encrypting data for the WLAN using a current session key, transmitting the data to the data terminal, receiving and decrypting data received from the WLAN using the current session key And terminating the secure communication session in response to receiving a logoff message from the WLAN, wherein the logoff message is in an encrypted form and includes the secure key;
A method comprising: A method for providing a secure communication session using a mobile terminal in a wireless local access network (WLAN) comprising:
Install at least two shared secrets in both the mobile terminal and the WLAN access point during the user authentication phase, whereby the first secret is the first session key and the second secret creates the following session key Used as a secure seed for;
A method comprising:   13. The method of claim 12, further comprising: creating a new key, encrypting the new key along with the current session key, and exchanging the new key between the WLAN and the mobile terminal. A method characterized by comprising.   13. The method of claim 12, further comprising the step of the WLAN and the mobile terminal creating a new session key using the new session key and the secure seed.   The method of claim 14, wherein generating the new key comprises combining the new key with the secure seed.   The method of claim 15, further comprising the step of creating a new session key by adapting a hash algorithm to the combined result.   The method according to claim 16, further comprising using the new session key in communication between the WLAN and a mobile terminal. A method for providing a secure communication session using a mobile terminal in a wireless local access network (WLAN) comprising:
Sending a mobile log terminal during session logoff with an encrypted logoff request with a secure seed such that the secure seed appears in the logoff request;
A method characterized by comprising: An access point for providing a secure communication session between a mobile terminal and a wireless local access network (WLAN):
Means for transmitting a first secure key and a second secure key to a mobile terminal using a secure communication method; and a session that encrypts data using the first secure key and continues using the second secure key Means for creating keys periodically;
An access point characterized by comprising: A terminal device for providing a secure communication session over a communication network comprising:
Means for receiving a first secure key and a second secure key and means for storing the first secure key and the second secure key 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, wherein the first secure key is initially used as the current session key Means for generating a subsequent session key using the current session key and the second secure key, wherein the subsequent session key is for subsequent communication Means used as the current session key;
A terminal device comprising:   21. The terminal device according to claim 20, wherein the terminal device is configured by a mobile terminal, and the communication network is configured by a wireless local access network (WLAN).   21. An access point for providing a secure communication session between a wireless local access network (WLAN) and a mobile terminal according to claim 20, wherein the means for periodically creating a subsequent session key is a new key An access point comprising means for creating a subsequent session key using a combination of the first secure key and the second secure key, wherein the new key is created by using the first secure key. 21. An access point for providing a secure communication session between a wireless local access network (WLAN) and a mobile terminal according to claim 20, wherein means for periodically creating a subsequent session key are new A means for creating a subsequent session key by combining the key and the second secure key, and means for executing a hash algorithm for creating the subsequent session key. access point.

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