KR20120074234A - Method and apparatus for supproting security in muliticast communication - Google Patents

Abstract

PURPOSE: A method for supporting security in multicast communication and an apparatus thereof are provided to support security in the multicast communication by using multicast a security key shared in a mobile station and a base station. CONSTITUTION: A base station and each mobile station shares a MAK(Multicast Authentication Key)(S410). The MAK is shared by a plurality of mobile stations as only a key in a multicast group. The base station and each mobile station produce a prekey for MCMAC(Multicast Cipher-based MAC) and a MTEK(Multicast Traffic Encryption Key), in other words, a MCMAC-MTEK prekey from the MAK(S420). The base station and each mobile station produce the MCMAC key and a plurality of MTEKs from the MCMAC-MTEK free key(S430). The base station and each mobile station codes or decodes a multicast traffic by using an MCMAC key and/or MTEK(S440).

Description

METHOD AND APPARATUS FOR SUPPROTING SECURITY IN MULITICAST COMMUNICATION}

The present invention relates to a method and apparatus for supporting security in multicast communication.

Multicast communication is used for group communication and the like in which a plurality of users participate in a call. In the group communication, since the same downlink traffic is transmitted to a plurality of users in the group performing the group communication at the same time, a plurality of users participating in the group communication with the base station can transmit a multicast connection for data transmission of the group communication.

Since the existing security support method supports only unicast communication but does not support multicast communication between a base station and a plurality of users, a security support method suitable for multicast communication is required.

An object of the present invention is to provide a security support method and apparatus capable of supporting multicast communication.

According to one embodiment of the present invention, a security support method for multicast communication at a mobile station is provided. The security support method. Sharing a multicast authorization key (MAK) with a base station, deriving a prekey based on a first parameter comprising the MAK, encrypting multicast traffic based on a second parameter comprising the prekey Deriving a multicast security key comprising a multicast traffic encryption key (MTEK), and decrypting multicast traffic using the multicast security key.

The first parameter may further include an identifier of the multicast group to which the mobile station belongs.

The first parameter may further include an identifier of a multicast group zone to which the base station belongs. In this case, the multicast group zone may include a base station set including at least one base station.

The security support method may include receiving a message including update information of the MTEK from the base station before the validity period of the MTEK expires, and determining whether to update the MTEK by comparing the update information with current information. And if the update information is different from the current information, updating the MTEK based on the update information.

The mobile station may maintain a current MTEK if the update information and the current information are the same.

The update information may include at least one of an encryption key serial number or a counter value used to derive the MTEK.

The update information may further include an expiration date of the MTEK.

The security support method may further include receiving a message including update information of the multicast security key from the base station, and updating the multicast security key based on the update information. In this case, the update information may include an identifier of the multicast group to which the multicast security key is to be updated, a flow identifier within the multicast group, or a connection identifier of the multicast group to which the multicast security key is to be updated.

According to another embodiment of the present invention, a security support method for multicast communication at a base station is provided. The security support method includes: sharing a MAK with a first mobile station, deriving a prekey based on a first parameter including the MAK, and multicast including a MTEK based on a second parameter including the freekey Deriving a security key, and encrypting multicast traffic using the multicast security key.

The first parameter may further include an identifier of the multicast group to which the first mobile station belongs.

The first parameter may further include an identifier of a multicast group zone to which the base station belongs. In this case, the multicast group zone may include a base station set including at least one base station.

The security support method may further include transmitting a message including update information of the MTEK to the first mobile station before the validity period of the MTEK expires. In this case, the update information may be compared with the current information of the first mobile station and used to determine whether the MTEK is updated.

The update information may include at least one of an encryption key serial number or a counter value used to derive the MTEK.

The update information may further include an expiration date of the MTEK.

The security support method may further include transmitting a message including update information of the multicast security key to the first mobile station. In this case, the update information may include an identifier of the multicast group to which the multicast security key is to be updated, a flow identifier within the multicast group, or a connection identifier of the multicast group to which the multicast security key is to be updated.

The security support method includes: subscribing a second mobile station to a multicast group to which the first mobile station belongs, transmitting a message including update information of a multicast security key to the second mobile station, and the multicast group The method may further include transmitting a message including update information of the multicast security key to another mobile station belonging to the mobile station.

The security support method may further include performing a withdrawal procedure of the multicast group with the first mobile station, and transmitting a message including update information of a multicast security key to another mobile station belonging to the multicast group. It may include.

According to another embodiment of the present invention, a security support apparatus for multicast communication is provided. The security support apparatus shares a MAK with a base station, derives a prekey based on a first parameter including the MAK, and derives a multicast security key including a MTEK based on a second parameter including the freekey. A security key generation unit, and an encryption / decryption unit that decrypts the multicast traffic using the multicast security key.

According to another embodiment of the present invention, a security support apparatus for multicast communication includes sharing a MAK with a mobile station, deriving a prekey based on a first parameter including the MAK, and a second parameter including the prekey. And a security key generation unit for deriving a multicast security key including the MTEK, and an encryption / decryption unit for encrypting multicast traffic using the multicast security key.

According to one embodiment of the present invention, it is possible to support security in multicast communication by using a multicast security key shared by the mobile station and the base station.

According to another embodiment of the present invention, when the multicast security key needs to be updated in multicast communication, the mobile station and the base station can share the updated multicast security key.

According to another embodiment of the present invention, the multicast security key can be renewed even before the expiration date expires, and the mobile station will not renew the multicast security key if it is not necessary even if the base station requests the renewal. It may be.

1 to 3 are diagrams schematically showing a multicast communication system according to an embodiment of the present invention.
4 is a diagram illustrating a security support method according to an embodiment of the present invention.
5 to 10 are diagrams illustrating a multicast security key update procedure in a security support method according to an embodiment of the present invention.
11 and 12 are block diagrams of a security support apparatus according to an embodiment of the present invention, respectively.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, a mobile station (MS) is a terminal, a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station (high). It may refer to a reliability mobile station (HR-MS), a subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), a user equipment (UE), or the like. It may also include all or part of the functions of the terminal, MT, AMS, HR-MS, SS, PSS, AT, UE and the like.

In addition, a base station (BS) may be an advanced base station (ABS), a high reliability base station (HR-BS), a node B (node B), an advanced node B (evolved node B, eNodeB), access point (AP), radio access station (RAS), base transceiver station (BTS), mobile multihop relay (MMR) -BS, relay serving as a base station station, RS), a high reliability relay (HR-RS) serving as a base station, etc., and may also refer to ABS, Node B, eNodeB, AP, RAS, BTS, MMR-BS, RS, HR. It may include all or part of functions such as -RS.

1 is a diagram illustrating a multicast communication system according to an embodiment of the present invention.

Referring to FIG. 1, the base station 110 assigns a multicast group identifier (ID) assigned to the multicast group 120 to provide multicast communication to a multicast group 120 including a plurality of mobile stations. Use The multicast group ID is uniquely assigned and has a finite size in the base station 110, and is used as an identifier informing the corresponding multicast group of the allocated resource. Different multicast groups 120, 130, and 140 have different multicast group IDs (MGID_A, MGID_B, MGID_C).

The base station 110 uses a flow identifier (FID) to distinguish a connection separately from the multicast group ID. The base station 110 may assign a FID to each multicast group ID to uniquely identify a connection, that is, a service flow, within the multicast group. Since the FID is an identifier for identifying a signal or traffic connection within the multicast group, the specific connection of the multicast group may be identified within the base station 110 by a combination of the multicast group ID and the FID. That is, the base station 110 uses the multicast group ID and the FID to provide a multicast service to the multicast group 120. In this case, the same FID (FID0 or FID1) may be used in different multicast groups 120, 130, and 140.

2 is a diagram illustrating a multicast communication system according to another embodiment of the present invention.

Referring to FIG. 2, the base station 210 uses a multicast group connection identifier (CID) assigned to the multicast service to provide a multicast service to the multicast group 220 including a plurality of mobile stations. use. The multicast CID is uniquely assigned and has a finite size to identify the connection (service flow) at the base station 210. Different multicast groups CID (MGCID0, MGCID1, MGCID2, MGCID3, MGCID4, MGCID5) are used in different multicast groups 220, 230, and 240. The multicast resource allocated to the multicast service may inform the multicast group through the multicast group CID.

Referring to FIG. 3, in a group communication system according to an embodiment of the present invention, a multicast group zone is defined by a base station set including at least one base station, and a multicast group zone is unique to the multicast group zone. ID is assigned. In a multicast group zone, multiple base stations use the same multicast group ID and FID (the embodiment of FIG. 1) or the same multicast group CID (the embodiment of FIG. 2) to transmit data of any service flow. . Accordingly, if the mobile station has already registered with the base station for the multicast service, even if the mobile station moves to another base station in the same multicast group zone, the mobile station can seamlessly receive the multicast service without registering with the other base station. If the mobile station moves to a base station providing the same multicast service in another multicast group zone, the mobile station can continue to receive the multicast service by updating a service flow related parameter.

When a multicast group zone is defined as a single base station, the single base station uses a multicast group CID for providing a multicast service independently of other base stations.

Next, the security support method of the multicast service will be described in detail with reference to FIGS. 4 to 10.

4 is a diagram illustrating a security support method according to an embodiment of the present invention.

Referring to FIG. 4, a base station and a plurality of mobile stations belonging to a multicast group manage a multicast specific key including a multicast CMAC (MCMAC) key and a multicast TEK (MTEK) to secure multicast communication. Here, CMAC means cipher-based message authentication code, and TEK means traffic encryption key.

First, the base station and each mobile station share a multicast authorization key (MAK) (S410). The MAK can be shared by multiple mobile stations with a unique key within the multicast group. A MAK can also be unique within a multicast group zone as well as a multicast group. If the multicast group zone is changed or the mobile station crosses the multicast group zone, the mobile station can update the MAK.

The base station and each mobile station derive a prekey for the MCMAC and MTEK from the MAK, that is, the MCMAC-MTEK prekey (S420). For example, as shown in Equation 1, the MCMAC-MTEK prekey may be derived using the length (160 bits) of the MAK, MAK_COUNT and MCMAC-MTEK prekeys. Here, MAK_COUNT is a counter used to guarantee different MCMAC keys and MTEK for handover, network reentry, location update, area change, etc. during multicast service. Unlike Equation 1, a multicast group ID (MGID) may be additionally used when deriving the MCMAC-MTEK prekey as shown in Equation 2. Alternatively, the multicast group zone ID (MGZoneID) may be additionally used as well as the MGID when deriving the MCMAC-MTEK prekey as shown in Equations 3 and 4. Alternatively, instead of the multicast group zone ID (MGZoneID) in Equations 3 and 4, a parameter in which each bit is set to a specific value may be used.

[Equation 1]

MCMAC-MTEK prekey = Dot16KDF (MAK, MAK_COUNT | "MCMAC-MTEK prekey", 160)

[Equation 2]

MCMAC-MTEK prekey = Dot16KDF (MAK, MAK_COUNT | MGID | "MCMAC-MTEK prekey", 160)

&Quot; (3) "

MCMAC-MTEK prekey = Dot16KDF (MAK, MAK_COUNT | MGID | MGZoneID | "MCMAC-MTEK prekey", 160)

&Quot; (4) "

MCMAC-MTEK prekey = Dot16KDF (MAK, MAK_COUNT | MGID ^ MGZoneID | "MCMAC-MTEK prekey", 160)

In Equations 1 to 4 and Equations described below, Dot16KDF is a function having as input a key, astring, and key length, for example, Dot16KDF as defined in IEEE Std 802.16-2009. It can be a function.

Next, the base station and each mobile station derives the MCMAC key and the plurality of MTEKs from the MCMAC-MTEK prekey (S430). The MCMAC key and MTEK can be generated whenever a new MAK is derived or a new MAK_COUNT is used. According to the characteristics of the multicast communication, only the MCMAC key (MCMAC_KEY_D) for downlink may be generated. For example, as shown in Equation 5, the MCMAC key may be derived using the length (128 bits) of the MCMAC-MTEK prekey and the MCMAC-MTEK prekey.Each MTEK (MTEKi) may be derived from the MCMAC-MTEK prekey, It can be derived using a multicast security association ID (MSAID) and the length (128 bits) of the MTEK. Here, a security association (SA) is a set of information required for secure communication between a base station and a mobile station. Multicast security associations (MSAs) are shared by base stations and mobile stations as SAs for multicast transport / control flows. MSAID is an ID that identifies the MSA.

[Equation 5]

MCMAC_KEY_D = Dot16KDF (MCMAC-MTEK prekey, "MCMAC_KEYS", 128)

&Quot; (6) "

MTEKi = Dot16KDF (MCMAC-MTEK prekey, MSAID | COUNTER_MTEK = i | "MTEK", 128)

The base station and each mobile station encrypts or decrypts the multicast traffic using the generated MCMAC key and / or MTEK (S440).

In FIG. 4, only the downlink MCMAC key MCMAC_KEY_D is generated, but in the case of multicast communication in which uplink multicast traffic exists, an uplink MCMAC key may be generated.

Next, a multicast security context which is a set of parameters related to a multicast security key will be described with reference to Tables 1 to 3.

The MAK context contains the parameters associated with the MAK and is created each time a new MAK is derived. The MAK context may include, for example, the parameters shown in Table 1.

parameter Size (bit) Usage MAK 160 Shared to mobile stations in a multicast group MAK lifetime 32 MAK validity period MAKID 64 Identify MAK MAK_COUNT 16 Value used to derive MCMAK key and MTEK MCMAC_KEY_D 128 Key used to sign downlink (DL) medium access control (MAC) control messages MCMAC_PN_D 24 It is used to avoid DL replay attacks on the control connection before this key expires and requires revalidation.
The initial value of MCMAC_PN_D is 0, and the value of MCMAC_PN_D is reset to 0 whenever MAK_COUNT is increased. Next available counter_MTEK 16 Counter value to be used in the next MTEK derivation
Increases by 1 after derivation

The MSA context is a parameter managed by each MSA and contains additional information pertaining to the MTEK context and the MSA itself. For example, the MTEK context may include the parameters shown in Table 2.

parameter Size (bit) Usage MSAID 8 Identifier of MSA describing the encryption / decryption method applied and MTEK context MTEK context MTEK context used for downlink

The MTEK context includes parameters associated with a single MTEK, and may include, for example, the parameters shown in Table 3.

parameter Size (bit) Usage MTEK 128 Key used to encrypt or decrypt MAC packet data units (PDUs) from the FID associated with the MSA. MEKS 2 Encryption key serial number COUNTER_MTEK 16 Counter value used to derive MTEK MTEK lifetime 32 MTEK validity period MTEK_PN_D 22 Packet number (PN) used to encrypt DL packets
After each MAC PDU transmission, this value is increased by one. PN Window Size Receiver tracks PNs received within the PN window

As described above, according to the embodiment of the present invention, it is possible to support security in multicast communication by using a multicast security key shared by the mobile station and the base station.

Next, a procedure for updating a multicast security key will be described in detail with reference to FIGS. 5 to 10.

5 to 10 are diagrams illustrating a multicast security key update procedure in a security support method according to an embodiment of the present invention.

Referring to FIG. 5, when updating a multicast security key, the base station 51 transmits paging for notifying update of the security key to a mobile station in the multicast group (S510). The mobile station 52 transmits a ranging request (RNG-REQ) message for updating the multicast security key to the base station 51 in response to the paging (S520). The base station 51 transmits a ranging response (RNG-RSP) message including the multicast security key update information to the mobile station 52 in response to the RNG-REQ message (S530). The paged mobile station 52 may also perform location update via RNG-REQ and RNG-RSP messages in idle mode.

Referring to FIG. 6, according to another embodiment, after the mobile station 62 reenters the network (S610), the base station 61 transmits a key update message including the multicast security key update information to the mobile station 62. (S620). This allows the mobile station 52 to update the multicast security key. In this case, the key update message may be, for example, a privacy key management response (PKM-RSP) message. The key update message may be delivered unicast to the mobile station 62 requiring multicast security key update. Alternatively, if another mobile station in the multicast group also needs a multicast security key update, the key update message may be sent to the mobile station in the multicast group in multicast.

Next, referring to FIG. 7, the mobile station 72 may not decrypt the message because there is no multicast security key information suitable for the encrypted message received from the base station 71. In this case, the mobile station 72 transmits a request message requesting the multicast security key update to the base station 71 (S710), and the base station 71 includes the multicast security key update information in response to the request message. The response message is transmitted to the mobile station 72 (S720). When the mobile station 72 performs location update or network reentry, the request message may be an RNG-REQ message or a PKM request (PKM-REQ) message, and the response message may be an RNG-RSP message or a PKM-RSP message. .

According to another embodiment, the multicast security key may be updated through the method described with reference to FIGS. 5 to 7 even when the multicast group zone is changed or the mobile station crosses the multicast group zone as well as location update or network reentry. have. In this case, the fact that the multicast security key is updated and information for updating can be transmitted from the destination base station of the moved cell. The update information may be transmitted through the above-described RNG-RSP or PKM-RSP message. In this case, in preparation for the change of the multicast group zone, the multicast security key may be updated through the previous base station before menstruation.

According to another embodiment, the multicast security key may be updated even within the same base station or the same multicast group zone. For example, the multicast security key may be updated when the validity period of the multicast security key expires or the configuration of the multicast group changes. The configuration of the multicast group may be changed by joining, leaving or changing a mobile station in the multicast group, or adding, deleting or changing a service flow. In this case, the base station and the mobile station may perform subscription, withdrawal, or change through the DSx procedure. The DSx procedure includes a subscription procedure through the exchange of a dynamic service addition request (DSA-REQ) message and a DSA response (DSA response, DSA-RSP) message, a dynamic service deletion request (DSD-REQ). Withdrawal procedure through the exchange of a DSD-RSP message and a DSD-RSP message or a change procedure through the exchange of a dynamic service change request (DSC-REQ) message and a DSC-RSP message. .

Referring to FIG. 8, when the mobile station 81 joins the multicast group, the mobile station 81 and the base station 82 exchange DSA-REQ and DSA-RSP messages (S810). The DSA-REQ and DSA-RSP messages may include a multicast group ID and a FID or multicast group CID.

The mobile station 81 then transmits the multicast security key request message to the base station 82 (S820), and the base station 82 sends the multicast security key response message including the multicast security key update information to the mobile station 81. It transmits (S830). In this case, the PKM-REQ message and the PKM-RSP message may be used as the multicast security key request message and the multicast security key response message, respectively.

In addition, the base station 82 transmits a message including the multicast key update information to another mobile station 83 in the multicast group (S840). Accordingly, the base station 82 may inform the other mobile stations 83 in the multicast group to the other mobile stations 83 in the multicast group and the facts of the multicast security key update and the updated contents. In this case, a PKM-RSP message may be used as a message transmitted to another mobile station 83.

Referring to FIG. 9, when the mobile station 91 leaves the multicast group, the mobile station 91 and the base station 92 exchange DSD-REQ and DSD-RSP messages (S910). The DSD-REQ and DSD-RSP messages may include a multicast group ID and a FID or multicast group CID.

In addition, the base station 92 transmits a message including the multicast key update information to another mobile station 93 in the multicast group (S920). In this case, the PKM-RSP message may be used as the message transmitted to the other mobile station 93. That is, the base station 92 can transmit the PKM-RSP message only to the other mobile station 93, thereby preventing the mobile station 91 that has left the multicast group from decoding the multicast data.

5 to 9, the multicast security key update information may include COUNTER_MTEK. The mobile station updates the MTEK based on COUNTER_MTEK. The multicast security key update information may further include a MEKS, and the mobile station may determine whether an MTEK update is necessary based on the MEKS. The multicast security key update information may further include an MTEK lifetime. In addition, the multicast security key update information may further include a multicast group ID and FID for updating the MTEK or a multicast group CID for updating the MTEK. Alternatively, the multicast security key update information may include information required for MAK update or MAK.

Thus, according to the embodiment of the present invention, when the multicast security key needs to be updated in multicast communication, the mobile station and the base station can share the updated multicast security key.

The mobile station and the base station may also renew the multicast security key when the validity period of the multicast security key, for example the MTEK validity period, expires. Alternatively, the multicast security key can be renewed even before the validity period of the multicast security key expires. Hereinafter, such an embodiment will be described with reference to FIG. 10.

Referring to FIG. 10, the base station 101 requests the MTEK update by sending a PKM-RSP message including the update information of the MTEK to the mobile station 102 before the validity period of the multicast security key, for example, MTEK, expires. It may be (S1010). MTEK update information may include the MEKS, COUNTER_MTEK and MTEK validity period. In this case, the PKM-RSP message may have a type indicating MTEK update. In addition, the MTEK update information may further include a FID to which the MTEK is updated and a multicast group ID or a multicast group CID to which the MTEK is updated.

The mobile station 102 compares the current MEKS with the MEKS of the received PKM-RSP message and determines whether the MEKS of the PKM-RSP message is the new MEKS (S1020). In the case of the new MEKS, the mobile station 102 updates the multicast security key, that is, MTEK, based on the multicast security key update information, for example, COUNTER_MTEK (S1030). If not a new MEKS, the mobile station maintains the existing multicast security key without renewing the multicast security key. Alternatively, the mobile station 102 may determine whether to renew the multicast security key by comparing the current COUNTER_MTEK with the COUNTER_MTEK of the received PKM-RSP message.

As described above, according to the embodiment of the present invention, the multicast security key can be renewed even before the expiration date expires, and the mobile station will not renew the multicast security key when the base station requests the renewal. It may be.

Next, a security support apparatus that performs a security support method according to an embodiment of the present invention will be described with reference to FIGS. 11 and 12.

11 and 12 are each a block diagram of a security support device according to an embodiment of the present invention.

Referring to FIG. 11, the security support apparatus 1100 includes a security key generator 1110, a transceiver 1120, and an encryption / decryption unit 1130. The security support device of FIG. 11 may be included in or be a mobile station.

The security key generation unit 1110 shares the multicast security key with the base station by generating or updating the multicast security key as described with reference to FIGS. 4 to 10. The transceiver 1120 transmits a multicast security key update request to the base station or receives a multicast security key update response from the base station. The encryption / decryption unit 1130 encrypts the multicast traffic to be transmitted or decrypts the received multicast traffic using the multicast security key.

Referring to FIG. 12, the security support apparatus includes a security key generator 1210, a transceiver 1220, and an encryption / decryption unit 1230. The security support device of FIG. 12 may be included in a base station or may be a mobile station.

The security key generation unit 1210 generates or updates a multicast security key to share the multicast security key with the mobile station as described with reference to FIGS. 4 to 10. The transceiver 1220 receives a multicast security key update request from the mobile station or transmits a multicast security key update response to the mobile station. The encryption / decryption unit 1230 encrypts the multicast traffic to be transmitted or decrypts the received multicast traffic using the multicast security key.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (19)

A security support method for multicast communication in a mobile station,
Sharing a multicast authorization key (MAK) with a base station;
Deriving a prekey based on a first parameter including the MAK,
Deriving a multicast security key comprising a multicast traffic encryption key (MTEK) based on a second parameter comprising the prekey, and
Decrypting multicast traffic using the multicast security key
Security support method comprising a. In claim 1,
And the first parameter further comprises an identifier of a multicast group to which the mobile station belongs. In claim 2,
The first parameter further includes an identifier of a multicast group zone to which the base station belongs,
The multicast group zone includes a base station set consisting of at least one base station.
How security is supported. In claim 1,
Receiving a message including update information of the MTEK from the base station before the validity period of the MTEK expires,
Determining whether the MTEK is updated by comparing the update information with current information; and
Updating the MTEK based on the update information if the update information is different from the current information.
Security support method further comprising. 5. The method of claim 4,
And the mobile station maintains a current MTEK if the update information and the current information are the same. 5. The method of claim 4,
Wherein said update information comprises at least one of an encryption key serial number or a counter value used to derive an MTEK. The method of claim 6,
The update information further includes a validity period of MTEK. In claim 1,
Receiving a message containing update information of the multicast security key from the base station, and
Updating the multicast security key based on the update information
More,
The update information includes an identifier of a multicast group to which the multicast security key is to be updated and a flow identifier within the multicast group or a connection identifier of the multicast group to which the multicast security key is to be updated.
How security is supported. A security support method for multicast communication at a base station,
Sharing a multicast authorization key (MAK) with a first mobile station,
Deriving a prekey based on a first parameter including the MAK,
Deriving a multicast security key comprising a multicast traffic encryption key (MTEK) based on a second parameter comprising the prekey, and
Encrypting multicast traffic using the multicast security key
Security support method comprising a. In claim 9,
The first parameter further comprises an identifier of a multicast group to which the first mobile station belongs. 11. The method of claim 10,
The first parameter further includes an identifier of a multicast group zone to which the base station belongs,
The multicast group zone includes a base station set consisting of at least one base station.
How security is supported. In claim 9,
Sending a message including update information of the MTEK to the first mobile station before the validity period of the MTEK expires,
The update information is compared with the current information of the first mobile station and used to determine whether the MTEK is updated.
How security is supported. The method of claim 12,
Wherein said update information comprises at least one of an encryption key serial number or a counter value used to derive an MTEK. In claim 13,
The update information further includes a validity period of MTEK. In claim 9,
Sending a message containing update information of the multicast security key to the first mobile station,
The update information includes an identifier of a multicast group to which the multicast security key is to be updated and a flow identifier within the multicast group or a connection identifier of a multicast group to which the multicast security key is to be updated,
How security is supported. In claim 9,
Joining a second mobile station to the multicast group to which the first mobile station belongs;
Sending a message containing update information of a multicast security key to the second mobile station, and
Transmitting a message including update information of the multicast security key to another mobile station belonging to the multicast group
Security support method further comprising. In claim 9,
Proceeding to leave the multicast group with the first mobile station, and
Transmitting a message including update information of a multicast security key to another mobile station belonging to the multicast group;
Security support method further comprising. As a security support device for multicast communication,
Sharing a multicast authorization key (MAK) with a base station, deriving a prekey based on a first parameter including the MAK, and multicast traffic encryption key based on a second parameter including the prekey ( a security key generation unit for deriving a multicast security key including a multicast traffic encryption key (MTEK), and
Encryption / decryption unit for decrypting multicast traffic using the multicast security key
Security support device comprising a. As a security support device for multicast communication,
Share a multicast authorization key (MAK) with a mobile station, derive a prekey based on a first parameter that includes the MAK, and multicast traffic encryption key based on a second parameter that includes the prekey ( a security key generation unit for deriving a multicast security key including a multicast traffic encryption key (MTEK), and
An encryption / decryption unit that encrypts multicast traffic using the multicast security key.
Security support device comprising a.

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