Wireless fast roaming method and system

Abstract

The invention provides a wireless rapid roaming method and system, and relates to the technical field of wireless communication, and the method comprises the steps that a second wireless access point deduces a first temporary key based on a key holder identifier of a first wireless access point and an MAC address of a wireless terminal carried in a rapid roaming request initiated by the wireless terminal, a rapid roaming authentication response is given; the wireless terminal derives a second temporary key based on a key holder identifier of the second wireless access point carried in the response and a layer of key information stored in the wireless terminal, and then initiates a rapid re-association request; and when the second wireless access point judges that the first temporary key is consistent with a second temporary key carried in the rapid re-association request, a rapid re-association reply carrying the group temporary key is given, and then the wireless terminal is switched to a channel of the second wireless access point to complete rapid roaming. The method has the beneficial effects that the calculation amount of the Home AP and the communication traffic between the Home AP and the neighbor AP are saved, and meanwhile, the storage consumption of the roaming key by the roaming AP is also saved.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a wireless fast roaming method and system. Background Art

[0002] With the rapid development of mobile Internet, wireless networks have penetrated into every corner of production and life. For crowded scenes such as hospitals, large commercial complexes, and transportation hubs, seamless switching of user terminals between multiple access points (APs) has become a key requirement. The traditional 802.11 protocol uses a full authentication process during roaming, resulting in a delay of hundreds of milliseconds. The 802.11r (Rapid Basic Service Set Transition) protocol uses a key pre-distribution mechanism to reduce the roaming switching delay to less than 50ms, significantly improving the quality of network services. The protocol defines two types of key systems: PMK_R0 (the initial pairwise master key generated by the Home AP) and PMK_R1 (the roaming key derived from PMK_R0). In conjunction with the mobile domain identification (MDID) mechanism, fast key negotiation between APs in the same security domain is achieved. This design creates a "zero-perception" network experience for mobile users while ensuring network security.

[0003] In the 802.11r wireless fast roaming protocol standard, in the "over-the_ds" mode, the terminal initiates an authentication request to the Home AP, the AP generates PMK_R0 and sends it through the wireless distribution system (DS), the terminal uses PMK_R0 to derive PMK_R1, and the terminal directly submits PMK_R1 to the target AP during switching. This mode is simple to implement, but it depends on the terminal capabilities and requires the terminal to support the 802.11r protocol. The key negotiation process occupies wireless channel resources, lacks centralized management and control capabilities, is difficult to adapt to complex network topologies, and has limited adaptability scenarios.

[0004] In the "over-the-air" mode, Figure 1 As shown in the figure, the Home AP (the AP that the wireless terminal associates with for the first time, i.e. R0KH) is the holder of PMK_R0, and needs to calculate the PMK_R1 value for other APs (i.e. R1KH) with the same MDID (Mobility Domain Id) and send it synchronously. However, due to the difference in R1KH_ID, Figure 1 R1KH_ID A 、R1KH_ID B 、R1KH_ID C 、R1KH_ID D , so that the PMK_R1 of each R1KH is also unique. For R1KH, PMK_R1 must be pre-stored for each wireless terminal, such as Figure 2As shown, it is used to trigger 802.11r fast roaming matching key. This method will not cause too many problems in small network environments with a small number of APs. However, in large WIFI network places, such as hospitals and shopping districts, the calculation of R0KH and the storage of R1KH for PMK_R1 will cause certain pressure on APs.

[0005] For large WIFI networks, the AC (access controller) management mode is often used. When a wireless terminal accesses the home AP for the first time, the AC assists the STA (terminal) in completing the authentication. The AC is the holder of PMK_R0 and calculates and derives the PMK_R1 for each AP. This method can greatly alleviate the calculation pressure of the Home AP, but other APs still need to store the corresponding PMK_R1 information for each wireless terminal, especially when there are a large number of wireless terminals, AP resources are tight. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides a wireless fast roaming method, in which at least a first wireless access point and a second wireless access point are configured in a wireless network, and a wireless terminal currently accesses the wireless network through the first wireless access point; the wireless fast roaming method comprises:

[0007] Step S1, when the wireless terminal moves to the coverage area of ​​the second wireless access point, the wireless terminal initiates a fast roaming request to the second wireless access point;

[0008] Step S2, the second wireless access point obtains a first temporary key based on the key holder identifier of the first wireless access point carried in the fast roaming request and the MAC address of the wireless terminal, and gives a fast roaming authentication response;

[0009] Step S3, the wireless terminal obtains a second temporary key based on the key holder identifier of the second wireless access point carried in the fast roaming authentication response and a layer of key information stored in the wireless terminal, and then initiates a fast reassociation request;

[0010] Step S4: The second wireless access point determines whether the first temporary key is consistent with the second temporary key carried in the fast reassociation request:

[0011] If not, roaming is terminated;

[0012] If yes, the second wireless access point gives a fast reassociation reply carrying the group temporary key, and then the wireless terminal switches to the channel of the second wireless access point to complete fast roaming.

[0013] Preferably, the step S2 comprises:

[0014] Step S21: The second wireless access point derives root key information based on the key holder identifier of the first wireless access point, the MAC address, and its own pre-configured information, and then gives the fast roaming authentication response.

[0015] Step S22: The second wireless access point derives first roaming key information based on the root key information it derives itself, its own key holder identifier, and the MAC address.

[0016] Step S23: The second wireless access point derives the first temporary key based on the first roaming key information, the first random number carried in the fast roaming request, the second random number it generates itself, its own basic service set identifier, and the MAC address.

[0017] Preferably, in step S21, the root key information includes a root key and its unique identifier, and the pre-configured information includes a pre-shared master key, the service set identifier of the wireless network, and a mobile domain identifier. The corresponding derivation formula is:

[0018]

[0019] In the above formula, PMK-R0Name-Salt = L(R0-Key-Data, 256, 128)

[0020] R0-Key-Data = KDF-384(XXKey, "FT-R0",

[0021] SSIDlength||SSID||MDID||R0KHlength||R0KH-ID||S0KH-ID)

[0022] Wherein, PMK_R0 represents the root key, PMK_R0Name represents the unique identifier of the root key, "FT-R0" and "FT-R0N" are fixed strings, XXKey represents the pre-shared master key, SSID represents the service set identifier of the wireless network, SSIDlength represents the number of bytes of SSID, MDID represents the mobile domain identifier, R0KH_ID represents the key holder identifier of the first wireless access point, S0KH_ID represents the MAC address of the wireless terminal, and R0KHlength represents the number of bytes of R0KH_ID.

[0023] Preferably, in step S22, the first roaming key information includes a first roaming key and its unique identifier, and the corresponding derivation formula is:

[0024]

[0025] Among them, PMK_R1 represents the first roaming key, PMK_R1Name represents the unique identifier of the first roaming key, "FT-R1" and "FT-R1N" are fixed strings, R1KH_ID is the key holder identifier held by the second wireless access point itself, and S1KH_ID is the MAC address of the wireless terminal.

[0026] Preferably, the derivation formula of the first temporary key is:

[0027]

[0028] Among them, PTK represents the first temporary key, PTKName represents the unique identifier of the first temporary key, "FT_PTK" and "FT_PTKN" are fixed strings, SNonce represents the first random number, ANonce represents the second random number, BSSID represents the basic service set identifier of the second wireless access point, and STA_ADDR represents the MAC address of the wireless terminal.

[0029] Preferably, the step S3 includes:

[0030] Step S31, the wireless terminal derives the second roaming key and its unique identifier according to the key holder identifier of the second wireless access point, its own MAC address, and the root key and its unique identifier stored as the layer key information by itself;

[0031] Step S32, the wireless terminal derives the second temporary key according to the second roaming key derived by itself, the basic service set identifier of the second wireless access point carried in the fast roaming authentication response and the second random number generated thereby, the first random number generated by itself, and its own MAC address.

[0032] Preferably, in the step S3, the wireless terminal also derives the message integrity check result on the terminal side based on the second temporary key and adds it to the fast re-association request;

[0033] In the step S4, the wireless access point also derives the message integrity check result on the access point side according to the first temporary key, and outputs a judgment result that the first temporary key is consistent with the second temporary key when the message integrity check result on the access point side is consistent with the message integrity check result on the terminal side.

[0034] The present invention also provides a wireless fast roaming system, which applies the above-mentioned wireless fast roaming method, and includes:

[0035] A wireless terminal that establishes communication with a first wireless access point, including a roaming request initiation module for initiating a fast roaming request to the second wireless access point when detecting that it has moved into the coverage area of the second wireless access point;

[0036] The second wireless access point includes a request response module for processing a first temporary key based on the key holder identifier of the first wireless access point and the MAC address of the wireless terminal carried in the fast roaming request and giving a fast roaming authentication response;

[0037] The wireless terminal further includes an association request initiation module for processing a second temporary key based on the key holder identifier of the second wireless access point carried in the fast roaming authentication response and the first layer key information stored by itself, and then initiating a fast re-association request;

[0038] The second wireless access point further includes a consistency check module for terminating roaming when the first temporary key is inconsistent with the second temporary key carried in the fast re-association request, and giving a fast re-association reply carrying a group temporary key when they are consistent, and then the wireless terminal switches to the channel of the second wireless access point to complete fast roaming.

[0039] Preferably, the request response module includes:

[0040] A first derivation unit for deriving root key information based on the key holder identifier of the first wireless access point, the MAC address, and its own pre-configured information, and then giving the fast roaming authentication response;

[0041] A second derivation unit connected to the first derivation unit for deriving first roaming key information according to the root key information derived by itself, its own key holder identifier, and the MAC address;

[0042] A third derivation unit connected to the second derivation unit for deriving the first temporary key according to the first roaming key information, the first random number carried in the fast roaming request, the second random number generated by itself, its own basic service set identifier, and the MAC address.

[0043] Preferably, the association request initiation module includes:

[0044] A fourth derivation unit for deriving a second roaming key and its unique identifier according to the key holder identifier of the second wireless access point, its own MAC address, and the root key and its unique identifier stored as the first layer key information by itself;

[0045] The fifth derivation unit is connected to the fourth derivation unit and is configured to derive the second temporary key according to the second roaming key obtained by its own derivation, the basic service set identifier of the second wireless access point carried in the fast roaming authentication response, the second random number generated thereby, the first random number generated by itself, and its own MAC address.

[0046] The above technical solution has the following advantages or beneficial effects:

[0047] During the fast roaming negotiation triggered by the wireless terminal, the second wireless access point that needs to roam and access can derive the temporary key by itself according to the information carried in the fast roaming request and the fast re-association request initiated by the wireless terminal. Without any interactive communication between the second wireless access point and the first wireless access point to which the wireless terminal is currently connected, the wireless terminal can smoothly complete fast roaming, saving the computing power of the Home AP (i.e., the first wireless access point AP1), the communication volume with the neighbor AP (such as the second wireless access point AP2), and also saving the storage consumption of the roaming key PMK_R1 by the roaming AP (such as the second wireless access point AP2). Description of the Drawings

[0048] Figure 1 It is a schematic diagram of the Home AP calculating the PMK_R1 value for other APs and synchronously sending it in the existing "over-the-air" mode;

[0049] Figure 2 It is a schematic diagram of the stored data of the roaming access point R1KH (AP) in the existing "over-the-air" mode;

[0050] Figure 3 It is a schematic flowchart of a wireless fast roaming method in a preferred embodiment of the present invention;

[0051] Figure 4 It is a general flowchart of wireless fast roaming in a preferred embodiment of the present invention;

[0052] Figure 5 It is a schematic sub-flowchart of step S2 in a preferred embodiment of the present invention;

[0053] Figure 6 It is a schematic sub-flowchart of step S3 in a preferred embodiment of the present invention;

[0054] Figure 7 It is a flowchart of the wireless terminal's first association with the AP in a preferred embodiment of the present invention;

[0055] Figure 8 It is a flowchart of the wireless terminal triggering fast roaming in a preferred embodiment of the present invention;

[0056] Figure 9 In a preferred embodiment of the present invention, it is a schematic structural diagram of a wireless fast roaming system. Specific implementation manner

[0057] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The present invention is not limited to this embodiment, and as long as it conforms to the gist of the present invention, other embodiments may also fall within the scope of the present invention.

[0058] In a preferred embodiment of the present invention, in view of the above problems existing in the prior art, a wireless fast roaming method is provided. At least a first wireless access point and a second wireless access point are configured in the wireless network, and the wireless terminal currently accesses the wireless network through the first wireless access point; as Figure 3 shown, the wireless fast roaming method includes:

[0059] Step S1, when the wireless terminal moves to the coverage area of the second wireless access point, a fast roaming request is sent to the second wireless access point;

[0060] Step S2, the second wireless access point processes the key holder identifier of the first wireless access point and the MAC address of the wireless terminal carried in the fast roaming request to obtain a first temporary key, and gives a fast roaming authentication response;

[0061] Step S3, the wireless terminal processes the key holder identifier of the second wireless access point carried in the fast roaming authentication response and the layer key information stored by itself to obtain a second temporary key, and then sends a fast re-association request;

[0062] Step S4, the second wireless access point determines whether the first temporary key is the same as the second temporary key carried in the fast re-association request:

[0063] If not, the roaming is terminated;

[0064] If so, the second wireless access point gives a fast re-association reply carrying the group temporary key, and then the wireless terminal switches to the channel of the second wireless access point to complete the fast roaming.

[0065] Specifically, as Figure 4 shown, the overall process of fast roaming of the wireless terminal STA in this embodiment is as follows:

[0066] 1. The wireless terminal STA currently accesses the wireless network through the first wireless access point AP1;

[0067] 2. When first associating with the AP, a fast roaming request (FT Authentication Request frame) will be sent to the second wireless access point AP2, and the authentication method is Open;

[0068] 3. The second wireless access point AP2 derives the root key PMK_R0 based on the information carried in the fast roaming request;

[0069] 4. The second wireless access point AP2 derives the first roaming key PMK_R1 for itself;

[0070] 5. The second wireless access point AP2 gives a fast roaming authentication response (FT Authentication Response) to the wireless terminal STA;

[0071] 6. The roaming is successful, and the wireless terminal STA switches to accessing the wireless network through the second wireless access point AP2.

[0072] It can be seen that the Home AP (i.e., the first wireless access point AP1) or the AC no longer needs to pre - know the key holder identifier R1KH_ID value of other APs (such as the second wireless access point AP2) and calculate and distribute the first roaming key PMK_R1 for it. The present invention is mainly applied to PSK authentication and works during the 802.11r fast roaming negotiation triggered by the wireless terminal. The roaming AP (R1KH, i.e., the second wireless access point AP2) derives the root key PMK_R0 and the first roaming key PMK_R1 by itself according to the information carried in the fast roaming request (FT Authentication Request frame). Without any interactive communication between R0KH (i.e., the first wireless access point AP1) and R1KH (i.e., the second wireless access point AP2), the wireless terminal STA can smoothly complete fast roaming. This solution saves the computing power of the Home AP (i.e., the first wireless access point AP1), the communication volume with neighbor APs (such as the second wireless access point AP2), and also saves the storage consumption of the roaming AP for PMK_R1.

[0073] In a preferred embodiment of the present invention, as Figure 5 shown, the process in which the above - mentioned second wireless access point AP2 derives the root key PMK_R0 based on the information carried in the fast roaming request and then derives the first roaming key PMK_R1 for itself includes:

[0074] Step S21, the second wireless access point derives the root key information based on the key holder identifier, MAC address of the first wireless access point, and its own pre - configured information, and then gives a fast roaming authentication response;

[0075] Step S22, the second wireless access point derives the first roaming key information according to the root key information derived by itself, its own key holder identifier, and MAC address;

[0076] Step S23: The second wireless access point derives a first temporary key based on the first roaming key information, the first random number carried in the fast roaming request, the second random number generated by itself, its own basic service set identifier, and the MAC address.

[0077] In a preferred embodiment of the present invention, as Figure 6 shown, step S3 includes:

[0078] Step S31: The wireless terminal derives a second roaming key and its unique identifier based on the key holder identifier of the second wireless access point, its own MAC address, and the root key and its unique identifier stored by itself as the layer one key information.

[0079] Step S32: The wireless terminal derives a second temporary key based on the second roaming key derived by itself, the basic service set identifier of the second wireless access point carried in the fast roaming authentication response and the second random number generated by it, the first random number generated by itself, and its own MAC address.

[0080] Specifically, in this embodiment, in a wireless network environment with WPA / WPA2-PSK authentication, to enable the wireless terminal STA to normally trigger 802.11r fast roaming, it is necessary to ensure that the pre-configuration information of each wireless access AP is the same, such as: including the same encryption method, pre-shared key, and MDID (Mobility Domain).

[0081] When the wireless terminal STA first associates with the AP, it is the same as the access method with 802.11r enabled normally, as Figure 7 shown, the specific process is as follows:

[0082] 1. When the wireless terminal STA first associates with the AP, it will send an Authentication Request frame to the AP, and the authentication method is Open (open system authentication), indicating that the wireless terminal STA supports open authentication without encryption.

[0083] 2. The AP replies with an Authentication Response to the wireless terminal STA, confirming the successful authentication and allowing the wireless terminal STA to enter the association stage.

[0084] 3. The wireless terminal STA sends an Association Request, carrying the mobile domain identifier MDID (used to identify the mobile domain to which the wireless terminal STA belongs, support fast roaming, and achieve fast handover across APs), network security configuration information RSNIE (Robust Security Network Information Element), and other relevant information, used to identify the mobile domain and security capabilities.

[0085] 4. The AP checks whether the mobility domain configuration information MDIE (Mobility Domain Information Element) matches the network security configuration information RSNIE. By verifying the matching of the MDID and RSNIE, it ensures that the security protocol supported by the terminal is consistent with the AP, that is, it ensures the compatibility of the terminal's security capabilities with the AP, and sends its own key holder identifiers R0KH_ID (used to identify the holder of the root key PMK_R0) and R1KH_ID (used to identify the holder of PMK_R1) to the wireless terminal STA through the AssociationResponse for subsequent key derivation.

[0086] 5. The wireless terminal STA and the AP start to derive the root key PMK_R0 and the unique identifier PMK_R0Name of the root key, that is, the first-level derived key, based on S0KH_ID (the identifier used to generate PMK_R0, which identifies the identity of the wireless terminal STA, usually the MAC address of the wireless terminal STA), the key holder identifier R0KH_ID of the AP, the mobility domain identifier MDID, and its own PMK (Pairwise Master Key).

[0087] 6. The wireless terminal STA and the AP calculate the second-level derived key for fast authentication for a single AP and its unique identifiers PMK_R1 and PMK_R1Name based on S1KH_ID (the identifier used to generate PMK_R1, usually the MAC address of the wireless terminal STA), R1KH_ID, and the derived root key PMK_R0 and the unique identifier PMK_R0Name of the root key by itself. The second-level derived key PMK_R1 is the session key associated with a specific AP, which enhances the dynamicity of the key. And by deriving the first-level derived key and then deriving the second-level derived key based on the first-level derived key, it ensures the hierarchy and security of the key.

[0088] 7. The AP initiates the 1 / 4th EAPOL_KEY handshake, which carries the ANonce random number, starts the key exchange, provides freshness, and prevents replay attacks.

[0089] 8. Subsequently, the wireless terminal STA starts to derive the PTK (Pairwise Transient Key) for encrypted communication based on the random value SNonce generated by itself, PMK_R1, and ANonce.

[0090] 9. The wireless terminal sends 2 / 4 EAPOL_KEY handshakes, carrying the SNonce, PMK_R1Name, and the MIC check of the message. Here, the MIC check is the message integrity check code calculated based on the temporary key PTK for the AP to verify, proving to the AP that it has correctly derived the PTK itself.

[0091] 10. The AP derives its own PTK, performs an MIC check on the 2 / 4 EAPOL_KEY messages sent by the wireless terminal STA, and confirms whether they are the same to ensure key consistency:

[0092] If the MIC is valid: It indicates that the PTKs of both sides are the same, and the process continues;

[0093] If the MIC is invalid: Terminate the handshake and request re - authentication.

[0094] 11. The AP sends information such as the GTK (Group Temporal Key) and MIC (Message Integrity Check) to the wireless terminal STA through 3 / 4 EAPOL_KEY to update the multicast key and ensure the security of multicast communication;

[0095] 12. The wireless terminal STA confirms that both sides have the same PTK and replies with a 4 / 4 EAPOL_KEY message, and the negotiation is completed.

[0096] After the above negotiation process is completed, on the one hand, the wireless terminal STA can negotiate the root key PMK_R0 and other security parameters (such as R0KH_ID, MDID, etc.). Among them, the root key PMK_R0 is the main session key, which is the basic key in the subsequent fast roaming process and is used to derive session keys. On the other hand, it can access the wireless network through the AP. The AP in this embodiment can be understood as the first wireless access point AP1. When the wireless terminal STA moves to the coverage area of the target access point (the second wireless access point AP2 in this embodiment), it will actively scan and discover the second wireless access point AP2 and initiate a fast roam to the target access point Target AP (the second wireless access point AP2 in this embodiment). The target access point derives the first temporary key PTK according to the information carried in the fast roam request and completes the roaming negotiation with the wireless terminal STA, as Figure 8 shown. The specific process is as follows:

[0097] 1. The wireless terminal STA initiates a fast roam, and the Authentication Request authentication type is FT, carrying the following key parameters:

[0098] The unique identifier PMK_R0Name of the root key;

[0099] Mobile Domain Identifier MDID;

[0100] Key Holder Identifier R0KH_ID of the first wireless access point;

[0101] Information such as the random number SNonce generated on the wireless terminal STA side.

[0102] 2. After the Target AP obtains the Key Holder Identifier R0KH_ID of the first wireless access point in the message, since it does not store any R0KH information, it starts to derive and calculate the PMK_R0 and PMK_R0Name information by itself. Among them, the root key information in step S21 includes the root key and its unique identifier, and the pre-configuration information includes the pre-shared master key, the service set identifier of the wireless network, and the mobile domain identifier. The corresponding derivation formula is:

[0103]

[0104] In the above formula, PMK-R0Name-Salt = L(R0-Key-Data, 256, 128)

[0105] R0-Key-Data = KDF-384(XXKey, "FT-R0",

[0106] SSIDlength||SSID||MDID||R0KHlength||R0KH-ID||S0KH-ID)

[0107] Among them, PMK_R0 represents the root key, PMK_R0Name represents the unique identifier of the root key, "FT-R0" and "FT-R0N" are fixed strings, XXKey represents the pre-shared master key, SSID represents the service set identifier of the wireless network, SSIDlength represents the number of bytes of SSID, MDID represents the mobile domain identifier, R0KH_ID represents the Key Holder Identifier of the first wireless access point, S0KH_ID represents the MAC address of the wireless terminal, and R0KHlength represents the number of bytes of R0KH_ID.

[0108] In the above R0-Key-Data derivation parameters, R0-Key-Data is generated by the KDF-384 function, using the pre-configured information combined with the R0KH_ID and S0KH_ID provided by the wireless terminal STA. The first 256 bits are extracted from R0-Key-Data as the root key PMK_R0, and at the same time, a hash value is generated as the unique identifier of the root key. Since all APs contain the same pre-configured information (SSID, XXKey, MDID are the same), the key holder identifier R0KH_ID of the first wireless access point is obtained from the Authentication Request of the fast roaming request of the wireless terminal STA. Therefore, for the calculation of R0-Key-Data, there is no difference between the Roaming AP (R1KH) and the Home AP (R0KH), and consistent result information can also be obtained for PMK_R0 and RMK_R0Name.

[0109] 3. The Target AP replies with an FT-type Authentication Response (i.e., fast roaming authentication response), which contains:

[0110] The unique identifier PMK_R0Name of the root key, which is obtained from the processing in step 2;

[0111] ANonce, which is a random number generated by the Target AP;

[0112] The key holder identifier R1KH_ID of the second wireless access point, which is its own held information;

[0113] The random number SNonce and R0KH_ID generated by the wireless terminal STA side, which are the information reported and carried by the wireless terminal STA.

[0114] 4. The wireless terminal STA then derives the second roaming key information PMK_R1 / PMK_R1Name according to the key holder identifier R1KH_ID, S1KH_ID of the second wireless access point and the stored root key PMK_R0, the unique identifier PMK_R0Name of the root key. Here, the second roaming key PMK_R1 is a dynamic key, which is specially generated for the roaming process and is used to establish a new secure connection with the new access point AP2 to achieve seamless handover.

[0115] 5. The wireless terminal STA continues to derive the second temporary key PTK according to the second roaming key PMK_R1, ANonce, SNonce, BSSID and its own MAC address. The second temporary key PTK is preferably generated by the KDF_PTKLen function and is used for encrypted communication.

[0116] 6. The wireless terminal STA sends a Fast Reassociation Request (FT Reassociation Request), which carries:

[0117] PMK_R1Name: used for the Target AP to verify the consistency of PMK_R1;

[0118] ANonce / SNonce: random numbers for both sides (ensuring the consistency of PTK derivation);

[0119] R1KH_ID / R0KH_ID, identifying the AP and the Home AP;

[0120] MIC derived using the PTK.

[0121] 7. The Target AP further calculates its own PMK_R1 / PMK_R1Name based on the self-derived PMK_R0 and PMK_R0Name, combined with S1KH and R1KH. Among them, the first roaming key information in step S22 includes the first roaming key and its unique identifier, and the corresponding derivation formula is:

[0122]

[0123] Among them, PMK_R1 represents the first roaming key, PMK_R1Name represents the unique identifier of the first roaming key, "FT-R1" and "FT-R1N" are fixed strings, R1KH_ID is the key holder identifier held by the second wireless access point itself, and S1KH_ID is the MAC address of the wireless terminal.

[0124] In the above derivation formula, R1KH_ID is held by itself, S1KH_ID is the wireless terminal MAC address, "FT-R1" and "FT-R1N" are fixed strings, so PMK_R0 / PMK_R0Name is consistent, and the result of PMK_R1 / PMK_R1Name derived by the wireless terminal STA will also be consistent.

[0125] 8. The Target AP continues to derive the PTK using PMK_R1, performs MIC verification on the message to be consistent with the report from the wireless terminal. Specifically, the derivation formula for the first temporary key is:

[0126]

[0127] Wherein, PTK represents the first temporary key, PTKName represents the unique identifier of the first temporary key, "FT_PTK" and "FT_PTKN" are fixed strings, SNonce represents the first random number, ANonce represents the second random number, BSSID represents the basic service set identifier of the second wireless access point, and STA_ADDR represents the MAC address of the wireless terminal.

[0128] Since the wireless terminal STA and the Target AP hold the common SNonce, ANonce, BSSID, and STA_MAC through interaction; and if the PMK_R1 is the same, the PTKs of both sides will also be the same, and the MIC will also pass the matching verification successfully.

[0129] 9. The Target AP replies with an FT Reassociation Response (i.e., a fast re-association response), carrying:

[0130] GTK: Group Temporary Key (used for multicast encryption).

[0131] MIC: Integrity Check Code generated based on the PTK.

[0132] SNonce, ANonce: Random numbers of both sides (to confirm consistency).

[0133] 10. After the authentication interaction between both sides is completed, the wireless terminal STA switches to the second wireless access point AP2, and the 802.11r roaming is successful.

[0134] In a preferred embodiment of the present invention, in step S3, the wireless terminal further derives the terminal-side message integrity check result based on the second temporary key and adds it to the fast re-association request;

[0135] In step S4, the wireless access point further derives the access point-side message integrity check result based on the first temporary key, and outputs a judgment result that the first temporary key is consistent with the second temporary key when the access point-side message integrity check result is consistent with the terminal-side message integrity check result.

[0136] The present invention also provides a wireless fast roaming system, which applies the above-mentioned wireless fast roaming method, as Figure 9 shown, including:

[0137] A wireless terminal STA, which establishes communication with the first wireless access point AP1, includes a roaming request initiation module 1, which is used to initiate a fast roaming request to the second wireless access point AP2 when detecting that it has moved into the coverage area of the second wireless access point AP2;

[0138] The second wireless access point AP2 includes a request response module 2, which is used to process the first wireless access point AP1's key holder identifier and the wireless terminal's MAC address carried in the fast roaming request to obtain a first temporary key, and give a fast roaming authentication response;

[0139] The wireless terminal STA further includes an association request initiation module 3, which is used to process the second wireless access point AP2's key holder identifier and the stored layer-1 key information of itself carried in the fast roaming authentication response to obtain a second temporary key, and then initiate a fast re-association request;

[0140] The second wireless access point AP2 further includes a consistency check module 4, which is used to terminate roaming when the first temporary key is inconsistent with the second temporary key carried in the fast re-association request, and give a fast re-association reply carrying the group temporary key when they are consistent, and then the wireless terminal switches to the channel of the second wireless access point AP2 to complete fast roaming.

[0141] In a preferred embodiment of the present invention, the request response module 2 includes:

[0142] A first derivation unit 21, which is used to derive root key information based on the first wireless access point AP1's key holder identifier, MAC address, and its own pre-configured information, and then give a fast roaming authentication response;

[0143] A second derivation unit 22, connected to the first derivation unit 21, which is used to derive first roaming key information according to the root key information derived by itself, its own key holder identifier, and MAC address;

[0144] A third derivation unit 23, connected to the second derivation unit 22, which is used to derive a first temporary key according to the first roaming key information, the first random number carried in the fast roaming request, the second random number generated by itself, its own basic service set identifier, and MAC address.

[0145] In a preferred embodiment of the present invention, the association request initiation module 3 includes:

[0146] A fourth derivation unit 31, which is used to derive a second roaming key and its unique identifier according to the second wireless access point AP2's key holder identifier, its own MAC address, and the root key and its unique identifier stored as layer-1 key information of itself;

[0147] A fifth derivation unit 32, connected to the fourth derivation unit 31, which is used to derive a second temporary key according to the second roaming key derived by itself, the basic service set identifier of the second wireless access point AP2 carried in the fast roaming authentication response and the second random number generated by it, the first random number generated by itself, and its own MAC address.

[0148] The above are only the preferred embodiments of the present invention, and do not limit the implementation and protection scope of the present invention accordingly. For those skilled in the art, it should be realized that any equivalent replacement and obvious changes made by using the content of this specification and the drawings should be included in the protection scope of the present invention.

Claims

1. A wireless fast roaming method, characterized in that, At least a first wireless access point and a second wireless access point are configured in the wireless network, and the wireless terminal currently accesses the wireless network through the first wireless access point; The wireless fast roaming method includes: Step S1, when the wireless terminal moves to the coverage range of the second wireless access point, a fast roaming request is sent to the second wireless access point; Step S2, the second wireless access point processes the received key holder identifier of the first wireless access point and the MAC address of the wireless terminal in the fast roaming request to obtain a first temporary key, and gives a fast roaming authentication response; Step S3, the wireless terminal processes the received key holder identifier of the second wireless access point in the fast roaming authentication response and the stored layer key information to obtain a second temporary key, and then sends a fast re-association request; Step S4, the second wireless access point determines whether the first temporary key is the same as the second temporary key carried in the fast re-association request: If not, the roaming is terminated; If so, the second wireless access point gives a fast re-association reply carrying a group temporary key, and then the wireless terminal switches to the channel of the second wireless access point to complete fast roaming.

2. The wireless fast roaming method according to claim 1, wherein The step S2 includes: Step S21, the second wireless access point derives root key information based on the key holder identifier of the first wireless access point, the MAC address, and its own pre-configured information, and then gives the fast roaming authentication response; Step S22, the second wireless access point derives first roaming key information based on the derived root key information, its own key holder identifier, and the MAC address; Step S23, the second wireless access point derives the first temporary key based on the first roaming key information, the first random number carried in the fast roaming request, the second random number generated by itself, its own basic service set identifier, and the MAC address.

3. The wireless fast roaming method according to claim 2, wherein In the step S21, the root key information includes a root key and its unique identifier, and the pre-configured information includes a pre-shared master key, the service set identifier of the wireless network, and a mobility domain identifier. The corresponding derivation formula is: In the above formula, PMK-R0Name-Salt = L(R0-Key-Data, 256, 128) R0-Key-Data = KDF-384(XXKey, "FT-R0", SSIDlength||SSID||MDID||R0KHlength||R0KH-ID||S0KH-ID) Among them, PMK_R0 represents the root key, PMK_R0Name represents the unique identifier of the root key, "FT-R0" and "FT-R0N" are fixed strings, XXKey represents the pre-shared master key, SSID represents the service set identifier of the wireless network, SSIDlength represents the number of bytes of SSID, MDID represents the mobile domain identifier, R0KH_ID represents the key holder identifier of the first wireless access point, S0KH_ID represents the MAC address of the wireless terminal, and R0KHlength represents the number of bytes of R0KH_ID.

4. The wireless fast roaming method according to claim 2, wherein In the step S22, the first roaming key information includes the first roaming key and its unique identifier, and the corresponding derivation formula is: Among them, PMK_R1 represents the first roaming key, PMK_R1Name represents the unique identifier of the first roaming key, "FT-R1" and "FT-R1N" are fixed strings, R1KH_ID is the key holder identifier held by the second wireless access point itself, and S1KH_ID is the MAC address of the wireless terminal.

5. The wireless fast roaming method according to claim 2, wherein The derivation formula of the first temporary key is: Among them, PTK represents the first temporary key, PTKName represents the unique identifier of the first temporary key, "FT_PTK" and "FT_PTKN" are fixed strings, SNonce represents the first random number, ANonce represents the second random number, BSSID represents the basic service set identifier of the second wireless access point, and STA_ADDR represents the MAC address of the wireless terminal.

6. The wireless fast roaming method according to claim 1, wherein The step S3 includes: Step S31, the wireless terminal derives the second roaming key and its unique identifier according to the key holder identifier of the second wireless access point, its own MAC address, and the root key and its unique identifier stored as the first layer key information. Step S32, the wireless terminal derives the second temporary key according to the second roaming key derived by itself, the basic service set identifier of the second wireless access point carried in the fast roaming authentication response and the second random number generated thereby, the first random number generated by itself, and its own MAC address.

7. The wireless fast roaming method according to claim 1, characterized in that In the step S3, the wireless terminal also derives the terminal-side message integrity check result based on the second temporary key and adds it to the fast re-association request. In the step S4, the wireless access point also derives the access point-side message integrity check result according to the first temporary key, and outputs a judgment result that the first temporary key is the same as the second temporary key when the access point-side message integrity check result is the same as the terminal-side message integrity check result.

8. A wireless fast roaming system, characterized in that, Applying the wireless fast roaming method according to any one of claims 1-7, including: A wireless terminal that establishes communication with a first wireless access point, including a roaming request initiation module for initiating a fast roaming request to the second wireless access point when detecting that it has moved into the coverage area of the second wireless access point; The second wireless access point includes a request response module for processing a first temporary key based on the key holder identifier of the first wireless access point and the MAC address of the wireless terminal carried in the fast roaming request and giving a fast roaming authentication response; The wireless terminal further includes an association request initiation module for processing a second temporary key based on the key holder identifier of the second wireless access point carried in the fast roaming authentication response and the layer key information stored by itself, and then initiating a fast re-association request; The second wireless access point further includes a consistency check module for terminating roaming when the first temporary key is inconsistent with the second temporary key carried in the fast re-association request, and giving a fast re-association reply carrying a group temporary key when they are consistent, and then the wireless terminal switches to the channel of the second wireless access point to complete fast roaming.

9. The wireless fast roaming system according to claim 8, wherein The request response module includes: A first derivation unit for deriving root key information based on the key holder identifier of the first wireless access point, the MAC address, and its own pre-configured information, and then giving the fast roaming authentication response; A second derivation unit connected to the first derivation unit for deriving first roaming key information according to the root key information derived by itself, its own key holder identifier, and the MAC address; A third derivation unit connected to the second derivation unit for deriving the first temporary key according to the first roaming key information, the first random number carried in the fast roaming request, the second random number generated by itself, its own basic service set identifier, and the MAC address.

10. The wireless fast roaming system according to claim 8, wherein, The association request initiation module includes: A fourth derivation unit for deriving a second roaming key and its unique identifier according to the key holder identifier of the second wireless access point, its own MAC address, and the root key and its unique identifier stored as the layer key information by itself; A fifth derivation unit connected to the fourth derivation unit for deriving the second temporary key according to the second roaming key derived by itself, the basic service set identifier of the second wireless access point carried in the fast roaming authentication response and the second random number generated by it, the first random number generated by itself, and its own MAC address.

Images