CN1298194C - Radio LAN security access method based on roaming key exchange authentication protocal - Google Patents

Abstract

The present invention relates to a radio LAN security access method based on a roaming cipher key exchange authentication protocol (EAP-RKE). An outdoor authentication server F-AS is used for substituting for a home authentication server H-AS to send authentication challenge to a mobile node MN. The mutual identity authentication of the mobile node MN and an access node AP is carried out, and a share cipher key is set. A network access identity NAI of the mobile node MN is userarealm, user is the identity of a user, and realm is a domain which the user belongs to. The user and the realm are separated, and the user is randomly encrypted to realize the protection of the identity of the user. An interactive turn number of protocol information between the outdoor authentication server F-AS and the home authentication server H-AS is 1 turn on the premise that the security of the present invention is ensured, performance is enhanced, and the identity of the user is simultaneously protected. When the mobile node MN is at a home domain and roams at an outdoor domain, the access control of the mobile node MN all can be realized, and the present invention can also ensure that the mobile node safely accesses a network.

Description

WLAN secure access method based on roaming key exchange authentication protocol

technical field

The invention belongs to the technical field of wireless communication security, in particular to a wireless local area network security access method (EAP-RKE) based on roaming key exchange authentication protocol, which provides security guarantee for local access and roaming access of mobile nodes.

the term

EAP-Extensible Authentication Protocol (Extensible Authentication Protocol)

NAI-Network Access Identifier

RADIUS-Remote Authentication Dial In User Service

AAA-Authentication, Authorization, and Auditing (Authentication, Authorization, Accounting)

TLS-Transport Layer Security (Transport Layer Security)

TTLS-Tunneled Transport Layer Security (Tunneled TLS)

PEAP - Protected Extensible Authentication Protocol (Protected EAP Protocol)

RKE-Roaming Key Exchange (Roaming Key Exchange)

MN-Mobile Node (Mobile Node)

AP-Access Point (Access Point)

AS-Authentication Server (Authentication Server)

F-AS-Foreign Authentication Server

H-AS- Home Authentication Server

KKS-Known Key Security (Known Key Security)

PFS-Perfect Forward Secrecy

N-KCI-No Key Compromise Impersonation

N-UKS-No Unknown Key Share

AVP-Attribute Value Pairs

MAC-Message Authentication Code

WAI-WLAN Authentication Infrastructure

Background technique

At present, IEEE 802.11 wireless local area network adopts the method based on wired equivalent privacy WEP (Wired Equivalent Privacy) for secure access control of wireless terminals and data security on wireless links.

Because WEP-based wireless LAN security technology has a lot of defects, many improvement methods have been proposed at present. The protocols based on public key technology include EAP-TLS (EAP Transport Layer Security), EAP-TTLS (EAP Tunneled TLS Authentication Protocol), PEAP (Protected EAP Protocol) and WAI (WLAN Authentication Infrastructure) used in GB15629.11. Except for WAI, others are encapsulated in the Extensible Authentication Protocol (EAP).

1.EAP-TLS

EAP-TLS is an authentication method based on TLS (Transport Layer Security), given by RFC2716. The authentication server and the client use the TLS protocol to negotiate the session key, and the protocol has five rounds of interaction. Its analysis is as follows:

1) Since both parties use public key certificates for authentication, and subsequent messages are carried out under the protection of public keys, attackers cannot obtain the real content of the message, nor can they tamper with the message. At the same time, random numbers are used to ensure freshness and prevent Replay attack. There is an attack method that allows both parties to negotiate a lower-strength algorithm group;

2) The protocol requires both parties to have public key certificates, which is difficult to operate in practice when the public key infrastructure is not widely deployed;

3) The protocol does not protect user identities, and the number of protocol interaction rounds is 5.

2. PEAP

PEAP eliminates the requirement for the mobile node's public key certificate, and its authentication process is divided into two stages: the first stage establishes a TLS tunnel for one-way server authentication; the second stage authenticates the mobile node under the protection of the tunnel. The protocol has good expansibility and adaptability, and corresponding authentication methods can be adopted for different mobile nodes. Its detailed description can be found in the literature http://www.ietf.org/internet-drafts/draft-josefsson-pppext-eap-tls-eap-07.txt, Oct 2003. Tool analysis is as follows:

1) The protocol eliminates the requirement for the mobile node public key certificate, has good scalability, can adopt suitable authentication methods for different mobile nodes, and has good adaptability. Because the first part of the protocol establishes a secure channel through EAP-TLS, under the protection of this secure channel, the authentication of the mobile node is completed, and the identity of the mobile node can be kept secret;

2) The protocol does not have the security properties of forward secrecy PFS and non-key leakage camouflage N-KCI, and the number of protocol interaction rounds must be greater than 5;

3.EAP-TTLS

EAP-TTLS is also a draft of IETF. It is very similar to PEAP. It also establishes a TLS tunnel authenticated by the server in the first stage, and authenticates the client in the second stage under the protection of the tunnel.

Their difference is that in the second phase, TTLS uses TLS tunnels to exchange "attribute-value pairs" (AVP), and the format of AVP is very similar to that of RADIUS AVP. This general encoding method enables TTLS to perform various authentication methods, not limited to the authentication methods supported by EAP, but also supports other methods (CHAP, PAP, MS-CHAP and MS-CHAPv2). Its detailed description can be found in http://www.ietf.org/internet-drafts/draft-ietf-pppext-eap-ttls-03.txt, Aug 2003. Its protocol flow is the same as PEAP.

Protocol analysis is the same as PEAP.

4. WAI

The State Intellectual Property Office published an invention patent application in 2003 (publication number: CN 14236200A). The patent involved in this patent application is applied in GB15629.11, referred to as WAI. WAI uses public key certificates for authentication and key negotiation. When the mobile node MN logs in to the wireless access point AP, the mobile node MN and the wireless access point perform mutual authentication through the authentication server AS; key. Since WAI does not adopt the form of EAP, the number of protocol interaction rounds is 2. When the mobile node is roaming, the message exchanged between the foreign authentication server and the home authentication server is one round. Its analysis is as follows:

1) The authentication part and the key negotiation part of the protocol are logically independent, and have advantages in key update;

2) The agreement does not have the nature of identity protection;

3) The mobile node MN and the wireless access point AP may generate inconsistent session keys.

There are obvious deficiencies in the above agreements. Although EAP-TLS has high security, it cannot provide identity protection; EAP-TTLS and PEAP change the use of TLS and provide identity protection, but lose some security properties and increase the number of protocol interaction rounds; WAI Although the number of interactive rounds of the protocol is small, the number of public key calculations performed by WAI on the access node AP is too large, which affects the performance of the AP, and cannot provide identity protection and session key consistency; in a wireless network environment, users The security threat received is greater than that of the wired network, so other benefits cannot be obtained at the expense of security; but for wireless mobile users, their identities need to be kept secret. To sum up, the current existing technologies can neither fully meet the security requirements of the wireless environment, nor meet the performance requirements of roaming protocols.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art above, to provide a wireless local area network security access method (EAP-RKE) based on the Roaming Key Exchange Authentication Protocol, which enables the authentication The protocol has the feature of identity protection, and the exchange of messages between the foreign authentication server F-AS and the home authentication server F-AS is one round, so as to ensure the safe access of the mobile node and meet the roaming requirements in the WLAN.

In order to solve the above-mentioned technical problems, the technical solution provided by the present invention is to adopt the roaming key exchange authentication protocol EAP-RKE, carry out mutual identity authentication between the mobile node MN and the access node AP, negotiate and establish a shared key, and its main steps include starting authentication , authenticate and establish a shared key and complete the authentication;

The start certification includes:

1) The mobile node MN sends an EAP start message to the access node AP;

2) The access node AP sends a message requesting the identity of the mobile node to the mobile node MN.

The authentication and establishment of a shared key includes:

1) The mobile node MN sends a message in response to the identity request to the access node AP, but the user's identity is empty;

2) The access node AP forwards the message sent by the mobile node MN to the foreign authentication server F-AS;

3) The foreign authentication server F-AS sends an EAP-RKE start message to the access node AP, requesting to start the EAP-RKE authentication. Include a random number N in the message as an access authentication challenge;

4) The access node AP forwards the message to the mobile node MN;

5) After the mobile node MN receives the message of starting EAP-RKE authentication, the mobile node MN generates a temporary public-private key pair, uses its temporary public key and the long-term private key of the home authentication server H-AS to calculate the identity encryption and decryption key, The identity of the node MN is encrypted; and the encrypted identity, the domain realm, the authentication challenge N sent by the foreign authentication server F-AS, the temporary public key of the mobile node MN and its signature are sent to the access node AP;

6) The access node AP forwards the received message to the foreign authentication server F-AS;

7) The foreign authentication server F-AS judges the hometown of the mobile node MN according to the domain realm in the message, if the mobile node is a local node, the foreign authentication server F-AS is the hometown authentication server of the mobile node; if not, it will receive The message is sent to the home authentication server H-AS of the corresponding mobile node;

8) The home authentication server H-AS decrypts the message to obtain the identity user of the mobile node MN and determines the long-term public key of the mobile node, and then uses the long-term public key to verify the signature of the mobile node. If the verification fails, the agreement is terminated; If passed, the home authentication server H-AS generates its own temporary public-private key pair, and uses its temporary private key and the temporary public key of the mobile node to calculate the master key and session key; then the home authentication server H-AS uses the authentication challenge N , the temporary public key of the mobile node MN (also as the authentication challenge) and the temporary public key of the home authentication server H-AS (also as the authentication challenge) and the identity encryption and decryption key to calculate the identity authentication message of the home authentication server H-AS, Finally, the home authentication server H-AS sends its identity authentication message, its temporary public key and session key to the foreign authentication server F-AS;

9) The foreign authentication server F-AS removes the session key in the received message, and transmits the remaining content to the access node AP;

10) The access node AP forwards the received message to the mobile node MN; after the mobile node MN receives the message, it verifies the identity authentication message of the home authentication server, and if the verification fails, the agreement is terminated; after the verification is passed, the mobile node MN uses its own The temporary private key and the temporary public key of the home authentication server H-AS calculate the master key and session key.

The completed certification includes:

5) The mobile node MN sends the EAP response message to the access node AP;

6) The access node AP forwards the message to the foreign authentication server F-AS;

7) The foreign authentication server F-AS sends a message of successful authentication to the access node AP, and the message contains the session key;

8) The access node AP sends a message of successful authentication to the mobile node MN.

According to the present invention, the mobile node MN adopts the same access method both in the home domain and when roaming to other regions, that is, roaming is transparent to the mobile node.

According to the present invention, the encrypted identity of the mobile node MN refers to the randomized encrypted identity

The randomized and encrypted identity of the mobile node MN may adopt the following method. The mobile node MN associates its identity with a random number, and then encrypts it with the public key of the home authentication server H-AS.

The identity authentication message of the home authentication server H-AS can be generated by the following method. The home authentication server H-AS signs with its own private key to generate the identity authentication message of the home authentication server H-AS.

The present invention realizes one round of message interaction between the home authentication server H-AS and the foreign authentication server F-AS; the master key is calculated by the temporary private key of the mobile node MN and the temporary public key of the home authentication server H-AS , which is also calculated by the temporary public key of the mobile node MN and the temporary private key of the home authentication server H-AS, and the master key obtained by the two calculations is consistent.

Compared with the above-mentioned prior art, the present invention has the following advantages:

1. The user identity user and the domain realm to which the user belongs are processed separately to realize user identity protection;

2. The authentication protocol interaction between the mobile node and the local area network is 4 rounds, and the message interaction between the foreign authentication server F-AS and the home authentication server H-AS is 1 round, which improves the protocol performance;

3. The protocol is provably secure under the security model proposed by Canetti and Krawczyk.

4. The protocol is provably secure under the security model proposed by Canetti and Krawczyk, then the protocol has the security properties of KKS, PFS and N-UKS. In the protocol, both communication parties must know their own private keys to generate the authentication payload, so the protocol also has the security property of N-KCI.

Table 1 The present invention compares with prior art security protocol identity protection provable safety PFS KKS N-KCI N-UKS EAP-TLS N * Y# Y Y# Y PEAP Y * Y# Y N Y EAP-TTLS Y * Y# Y N Y WAI N * N Y N N EAP-RKE Y Y Y Y Y Y

Note: # refers to the key exchange algorithm that must use temporary public-private and signature

* means not made

It can be seen from the comparison in Table 1 that the security performance of the security access method based on EAP-RKE in the present invention is much better than that of the prior art as a whole.

Description of drawings

Fig. 1 is the EAP-RKE authentication process diagram of the present invention

Fig. 2 is a logical structural diagram of the security authentication system of the present invention

Fig. 3 is the mobile node of the present invention at home town EAP-RKE and EAP-TLS agreement to the impact emulation contrast figure of communication

Fig. 4 is the mobile node of the present invention in the field EAP-RKE and EAP-TLS agreement impact emulation contrast figure on communication

Description of symbols in Figure 1:

The message format is: message type w/{message content}. The message types are as follows:

EAP-Start begins to extend the authentication protocol EAP;

EAP-Rqst/RKE EAP-RKE request message;

EAP-Resp/RKE EAP-RKE response message;

EAP-Rqst/ID EAP request identity message;

EAP-Resp/ID EAP response identity message;

EAP-Rqst/RKE start Start the EAP-RKE protocol message;

Radius-Rqst Radius protocol request message;

Radius-Acct Radius protocol acceptance message;

EAP-Success EAP successfully completed message.

The content of the message is described as follows:

u Private key of the mobile node;

g ^u public key of the mobile node;

user User identity of the mobile node MN;

realm The domain to which the mobile node MN belongs;

a Private key of H-AS;

g ^a public key of H-AS;

Certificate of Cert _A H-AS;

E(k;.) Encryption function of symmetric encryption whose key is k;

MAC(k;.) Message authentication code function with key k;

Sig signature function;

prf(k;.) Pseudo-random function with key k, used for session key derivation function.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the present invention is described in detail:

Referring to Figure 2, MN is a mobile node, AP is an access node, and F-AS and H-AS are foreign and home authentication servers respectively.

The dotted line in Figure 2 represents a logical secure connection, and the solid line represents an actual physical connection. The mobile node MN and its home authentication server H-AS share a security association (shared key or through public key certificate). There is a secure channel between the access node AP and the foreign authentication server F-AS, and the access node AP and the foreign authentication server F-AS trust each other; there is also a secure channel between the foreign authentication server F-AS and the home authentication server H-AS, and the foreign authentication server F-AS is trusted by the home authentication server H-AS, based on this, the present invention uses the foreign authentication server F-AS instead of the home authentication server H-AS to issue an authentication challenge to the mobile node MN, so that the foreign authentication server F-AS and the home The message interaction between the authentication servers H-AS is realized in one round.

When the mobile node MN logs in to the access node AP, in order to realize the secure access of the MN, the mobile node MN and the access node AP need to confirm each other's identities and establish a shared key. The present invention adopts EAP-RKE to realize identity authentication and key negotiation, and its identity authentication and key establishment implementation mode are as shown in Figure 1, specifically include the following steps:

1. Start authentication

1) The mobile node MN sends an EAP start message to the access node AP;

2) The access node AP sends a message requesting the identity of the mobile node MN to the mobile node;

2. Authenticate and establish a shared key

1) The mobile node MN sends a message in response to the identity request to the access node AP, but the user's identity is empty;

2) The access node AP forwards the message sent by the mobile node MN to the foreign authentication server F-AS;

3) The foreign authentication server F-AS sends an EAP-RKE start message to the access node AP, requesting to start the EAP-RKE authentication. A random number N is included in the message as an access authentication challenge identifier;

4) The access node AP forwards the message to the mobile node MN;

5) After receiving the message of starting EAP-RKE authentication, the mobile node MN generates a temporary private key x and a temporary public key g ^x . Calculate the identity encryption and decryption key K=(g ^x ) ^a with its own temporary public key g ^x and the long-term private key a of the home authentication server H-AS, and encrypt the identity of the mobile node MN. Use its encrypted identity Enc(K; user), the domain it belongs to, the authentication challenge N sent by the foreign authentication server F-AS, the temporary public key g ^x and the signature AUTH1 of the mobile node MN=Sigu(g ^x |N|Enc (K; user)) message is sent to the access node AP;

6) The access node AP forwards the message to the foreign authentication server F-AS;

7) The foreign authentication server F-AS judges the hometown of the mobile node MN according to the domain Realm in the message, if the mobile node is a local node, the foreign authentication server F-AS is the hometown authentication server H-AS of the mobile node; Send the message {Enc(K; user), N, g ^x , AUTH1} to the home authentication server H-AS of the corresponding mobile node;

8) After the home authentication server H-AS receives the message, it calculates the identity encryption and decryption key K=(g ^x ) ^a with its own long-term private key a and the temporary public key g ^x of the mobile node MN, and decrypts Enc(K; user), get the identity user of the mobile node MN and determine the long-term public key g ^u of the mobile node, then the home authentication server H-AS uses the public key g ^u to verify the signature authentication payload AUTH1 of the mobile node, and if the verification fails, the agreement is terminated; If the verification is passed, the home authentication server H-AS generates a temporary private key y and a temporary public key g ^y . The home authentication server H-AS uses its own temporary private key y and the mobile node's temporary public key g ^x to calculate the master key K _master =(g ^x ) ^y , and the session key K _s =prf(K _master ; 0). Then the home authentication server H-AS uses the identity encryption and decryption key K to authenticate the challenge N, the temporary public key g ^x of the mobile node MN (also used as the authentication challenge) and the temporary public key g ^y of the home authentication server H-AS (also used as authentication challenge) calculates the identity authentication message AUTH2=MAC(K; N|g ^x |g ^y ) of the home authentication server H-AS, and then the home authentication server H-AS sends the identity authentication message AUTH2=MAC(K; N|g ^x |g ^y ), the temporary public key g ^y , and the session key K _s =prf(K _master ; 0) are sent to the foreign authentication server F-AS.

9) The foreign authentication server F-AS removes the session key K _s in the message, and transmits the remaining {g ^y , AUTH2} to the access node AP;

10) The access node AP forwards the message to the mobile node MN. After the mobile node MN receives the message, it verifies the identity authentication message AUTH2 of the home authentication server, and if the verification fails, the agreement is terminated; after the verification is passed, the mobile node MN uses its own temporary private key x and the temporary public key g of the home authentication server H-AS ^y calculation master key Kmaster=(g ^y ) ^x , session key K _s =prf(K _master ; 0);

3. After completing mutual authentication and key negotiation, the access point AP obtains the shared key with the mobile node MN

1) The mobile node MN sends the EAP response message to the access node AP;

2) The access node AP forwards the message to the foreign authentication server F-AS;

3) The foreign authentication server F-AS sends a message of successful authentication to the access node AP, and there is a session key K _s in the message;

4) The access node AP sends a message of successful authentication to the mobile node MN.

So far, the mobile node MN and the access node AP have completed mutual authentication and obtained the same session key K _s . In other words, secure access of the mobile node MN is completed. In the above authentication and key agreement process, the foreign authentication server F-AS is used instead of the home authentication server H-AS to issue a challenge to the mobile node MN, and the information exchange between the foreign authentication server F-AS and the home authentication server H-AS is realized as 1 round. In addition, the identity authentication of the mobile node MN and the access point AP and the establishment of the shared key are carried out synchronously.

It should be pointed out that the above access method based on EAP-RKE is not only applicable to the access of the mobile node MN in the home domain, but also applicable to the access of the mobile node roaming to other regions, that is, the roaming is transparent to the mobile node.

In the identity authentication process shown in Figure 1, another implementation manner to the identity encryption of the mobile node MN is:

The mobile node MN associates its identity user with a random number m, such as concatenating user and m or performing XOR operation on user and m, and then encrypts it with the public key g ^a of the home authentication server H-AS. Send the encrypted identity and the random number m to the home authentication server H-AS.

In the identity authentication process shown in Figure 1, another implementation of the identity authentication of the home authentication server H-AS is:

The home authentication server H-AS uses its private key a to sign, and generates the identity authentication message of the home authentication server H-AS.

EAP-RKE performance comparison

An important aspect of protocol performance is the number of interaction rounds. If the number of interaction rounds is large, the time required for the completion of the agreement is also large. And with the development of IEEE 802.11 wireless local area network, the mobile node will roam between different management domains, and the mobile node may need to be authenticated during the roaming process.

After the mobile node roams to a foreign network, the maximum delay for authentication is the transmission delay between F-AS and H-AS. However, the number of interaction rounds of EAP-TLS is 5 rounds, and there are 2 rounds of interaction between the F-AS and the H-AS during roaming. As for EAP-TTLS, according to the authentication form adopted in the second stage, the number of interaction rounds is greater than that of EAP-TLS. Therefore, they do not meet the requirements. The present invention adopts EAP-RKE to achieve 4 rounds of interaction, and only 1 round of message transmission between F-AS and H-AS.

In order to compare the performance of the protocol vividly, the performance of the protocol is simulated, and the comparison protocol is EAP-TLS. Adopt NS-2.26 as the simulation platform, work on a PC (C1.7G, 256M RAM), and the operating system is Red Hat Linux8.0.

The impact of authentication on normal data flow is shown in Figure 3 and Figure 4. In the figure, the abscissa is the sequence number of the data packet, and the ordinate is the time difference between two adjacent data packets arriving at the destination, in seconds. The solid line represents the situation of the EAP-TLS protocol, and the dotted line represents the situation of the EAP-RKE protocol. The highlighted part in the figure is the delay introduced by the authentication protocol.

Fig. 3 is the case of the mobile node in the home domain, and Fig. 4 is the case of the mobile node in the foreign area.

It can be seen from Figure 3 and Figure 4 that the protocol authentication delay is much better than that of EAP-TLS, which strongly proves that the present invention has good performance and can greatly improve the roaming efficiency of IEEE 802.11 WLAN.

Claims (4)

1. wireless LAN safety cut-in method " EAP-RKE " based on roaming cipher key change authentication protocol, adopt Extensible Authentication Protocol EAP to carry out mutual authentication in mobile node MN and access node AP, consult to set up share key, its key step comprises and begins authentication, authenticates and set up and share key and finish authentication;

Described begin the authentication comprise:

1) mobile node MN begins message to EAP and issues access point AP;

2) access point AP sends to mobile node MN to the message of request mobile node identity;

Described authentication and foundation are shared key and are comprised:

1) mobile node MN sends to access node AP to the message of response identity request, but user's identity is empty;

2) access node AP forwards that mobile node MN is sent is given nonlocal certificate server F-AS;

3) nonlocal certificate server F-AS sends the message that EAP-RKE begins to access node AP, requires the authentication of beginning EAP-RKE, comprises a random number N in message, identifies as the access authentication challenge;

4) access node AP gives mobile node MN forwards;

5) after mobile node MN is received the message of beginning EAP-RKE authentication, mobile node MN generates interim public private key pair, adopt the method for randomized encryption, calculate identity encryption and decryption key with the long-term private of its interim PKI and local certificate server H-AS, the identity ciphering of mobile node MN; Described encryption and decryption key is: K=(g ^x) ^a, in the formula, x, g ^xBe the temporary private of MN, interim PKI; A is the long-term private of H-AS;

6) identity, affiliated territory realm, the authentication challenge N that nonlocal certificate server F-AS sends, the interim PKI of mobile node MN and the signature of mobile node MN after mobile node MN is encrypted it send to access node AP;

7) access node AP gives nonlocal certificate server F-AS with the forwards of receiving;

8) nonlocal certificate server F-AS judges the local of mobile node MN according to the affiliated territory realm in the message, if mobile node is a local node, and the local certificate server that then nonlocal certificate server F-AS is exactly a mobile node; As not being the local certificate server H-AS that then message of receiving is sent to the corresponding mobile node;

9) after certificate server H-AS in local received message, deciphering obtained the identity user of mobile node MN and determines the long-term PKI of mobile node, utilizes the signature of this long-term public key verifications mobile node then, if authentication failed termination protocol then; If checking is passed through, then certificate server H-AS in local generates the interim public private key pair of oneself, utilizes the interim PKI of its temporary private and mobile node MN to calculate master key and session key;

Described master key is: K _Master=(g ^x) ^y

Described session key is: K _s=prf (K _Master0)

In the following formula, y is the temporary private of H-AS;

10) certificate server H-AS in local utilizes the interim PKI " also as authentication challenge " of authentication challenge N, mobile node MN, the interim PKI " also as authentication challenge " of local certificate server H-AS and the identity that identity encryption and decryption key K calculates local certificate server H-AS to differentiate message AUTH2=MAC (K; N|g ^x| g ^y), wherein, g ^yBe interim PKI, local certificate server H-AS differentiates message AUTH2, interim PKI g with its identity ^yWith session key K _sSend to nonlocal certificate server F-AS;

11) nonlocal certificate server F-AS is the session key K in the message of receiving _sDeletion is remaining " g ^y, AUTH2 " and content sends access node AP to;

12) access node AP issues mobile node MN to the message of receiving; Mobile node MN receives that the identity of checking local certificate server after the message differentiates message, and authentication failed is termination protocol then; After checking was passed through, mobile node MN utilized temporary private of oneself and the interim PKI of local certificate server H-AS to calculate master key and session key;

Described master key is: K _Master=(g ^y) ^x

Described session key is: K _s=prf (K _Master0);

Described finish the authentication comprise:

1) mobile node MN sends to access node AP to the EAP response message;

2) access node AP gives nonlocal certificate server F-AS forwards;

3) nonlocal certificate server F-AS sends to access node AP to the message of authentication success, contains session key in the message;

4) access node AP sends to mobile node MN to the message of authentication success.

2. the wireless LAN safety cut-in method based on roaming cipher key change authentication protocol according to claim 1, it is characterized in that mobile node the territory, local with roam into outside the region all adopt identical cut-in method, it is transparent promptly roaming for mobile node.

3. the wireless LAN safety cut-in method based on roaming cipher key change authentication protocol according to claim 1, it is characterized in that described mobile node MN is related with a random number with its identity, with the PKI of local certificate server H-AS identity is encrypted then.

4. the wireless LAN safety cut-in method based on roaming cipher key change authentication protocol according to claim 1, tool is characterised in that the identity discriminating message of described local certificate server H-AS adopts following method to produce, local certificate server H-AS utilizes the private key of oneself to sign, and the identity that generates local certificate server H-AS is differentiated message.

Images