KR100611577B1 - Authenticating method in complex mode mobile terminal and mobile terminal using the same - Google Patents

Abstract

We propose an authentication method in a multi-functional mobile terminal having a relay function between mobile terminals. To this end, a pre-authentication method is provided in which an unauthenticated mobile terminal selects a pre-authenticated mobile terminal, receives pre-authentication, and transmits an authentication request packet to the selected mobile terminal. In addition, in the case of a data packet, a method for authenticating between mobile terminals through verification using a network key is provided. In this way, an illegal packet inflow can be prevented against a denial of service attack from an illegal mobile terminal, and unnecessary authentication request packets can be reduced.

Authentication, hybrid network, relay, cellular, pre-authentication, ICD, certificate

Description

Authentication method in composite function mobile terminal and mobile terminal using same {AUTHENTICATING METHOD IN COMPLEX MODE MOBILE TERMINAL AND MOBILE TERMINAL USING THE SAME}

1 is a diagram illustrating a logical hybrid network according to an embodiment of the present invention.

2 is a diagram illustrating the concept of a packet authentication method according to a first embodiment of the present invention.

3 is a flowchart illustrating a packet authentication method in a relay mobile terminal according to a first embodiment of the present invention.

4 is a flowchart illustrating a packet authentication method in a destination mobile terminal.

5 is a diagram illustrating the concept of a pre-authentication method according to a second embodiment of the present invention.

6 is a flowchart illustrating a pre-authentication method according to a second embodiment of the present invention.

7 is a diagram for explaining an authentication method according to a third embodiment of the present invention.

The present invention relates to an authentication method in a multi-function mobile terminal and a mobile terminal using the same, and more particularly, to an authentication method in a dual mode mobile terminal having a relay function between mobile terminals.

The composite function mobile terminal is a mobile terminal having a relay function between mobile terminals in addition to the mobile communication function. The logical hybrid network for such a multi-functional mobile terminal is a mixture of a mobile communication network such as a cellular network and a relay network between mobile terminals such as an adhoc network.

In such a logical hybrid network, an illegal mobile terminal may transmit a packet to the hybrid network by broadcasting the packet through a relay interface. This packet transmission wastes wireless bandwidth and places unnecessary load on the mobile terminal relaying the packets. The introduction of such illegal packets into a hybrid network is called a denial of service (DoS) attack. A denial of service attack may occur during packet transmission or during authentication of a mobile terminal.

In addition, since the illegal mobile terminal user can use the route request packet to start a denial of service attack, the mobile terminal must first perform the authentication process before executing the route setting process. Therefore, because many mobile terminals receive packets at the same time and send them to different routes, in a logical hybrid network the mobile stations broadcast unnecessary authentication request packets to an authentication, authorization and accounting (AAA) server or access station. do. This unnecessary authentication request packet not only wastes network resources, but also causes excessive load on the AAA server.

As such, the conventional end-to-end encryption (RFC2402, IP authentication header) in a logical hybrid network cannot prevent the intrusion of the authentication request packet due to a denial of service attack and is legal when the packet is changed in the middle. It is not effective for detecting a modified packet by a mobile terminal or detecting a mobile terminal masquerading to the originating mobile terminal.

In addition, in the logical hybrid network, the conventional mobile terminal authentication technology (terminal authentication, 3GPP technical specification group services and system aspects, 3G security, security architecture) does not prevent unnecessary authentication request packet generation, Inflow cannot be blocked.

The technical problem to be achieved by the present invention is to provide an authentication method that can block the inflow of the authentication request packet due to a denial of service attack.

Another object of the present invention is to provide an authentication method capable of detecting packet modification by a legitimate mobile terminal and detecting an illegal mobile terminal disguised as an outgoing mobile terminal.

Another technical problem to be achieved by the present invention is to provide an authentication method that can prevent the generation of unnecessary authentication request packets.

In order to solve this problem, the present invention verifies a packet by using information shared between legitimate mobile terminals, and is pre-authenticated through a pre-certified mobile terminal.

According to one aspect of the present invention there is provided an authentication method in a multi-function mobile terminal having a mobile communication function and a relay function between mobile terminals. The authentication method of the present invention comprises the steps of: a) a first mobile terminal receiving a packet including first packet acknowledgment data from a second mobile terminal; b) calculating and comparing second packet acknowledgment data with the first packet acknowledgment data by the first mobile terminal; And c) if the comparison result in step b) matches, transmitting the packet received in step a) to the next node or higher layer. In this case, the first and second packet acknowledgment data are generated by information shared between the legitimate mobile terminals.

According to one embodiment of the invention, the information shared between legitimate mobile terminals comprises a network key.

According to another embodiment of the present invention, the packet received by the first mobile terminal from the second mobile terminal further includes third packet acknowledgment data. Here, when the first mobile terminal is the final destination mobile terminal, the authentication method of the present invention, the first mobile terminal calculates the fourth packet confirmation data and compare with the third packet confirmation data, and the comparison result is the same And the first mobile terminal transmitting the packet to a higher layer. In this case, the third and fourth packet acknowledgment data are generated by information shared between legitimate end-to-end mobile terminals.

According to another embodiment of the present invention, information shared between legitimate end-to-end mobile terminals includes end-to-end keys.

According to another aspect of the present invention, an authentication method is provided in a multi-function mobile terminal having a mobile communication function and a relay function between mobile terminals. The authentication method of the present invention comprises the steps of: broadcasting, by a first mobile terminal, a pre-authentication request packet including information of a first mobile terminal, from at least one second mobile terminal receiving a pre-authentication request packet by the first mobile terminal; Receiving an authentication response packet including a part of the information of the first mobile terminal and the information of the second mobile terminal, and if the verification result is valid after the first mobile terminal verifies the authentication response packet, authentication with the second mobile terminal Making a request.

According to an embodiment of the present invention, the information of the first mobile terminal includes a time stamp, an identifier of the first mobile terminal, a signature of the first mobile terminal, and a certificate of the first mobile terminal, and among the information of the first mobile terminal. Some include a certificate of the first mobile terminal.

According to another embodiment of the present invention, the information of the second mobile terminal includes a time stamp, an identifier of the second mobile terminal and a signature of the second mobile terminal.

According to another embodiment of the present invention, the authentication method of the present invention further includes the step of the first mobile terminal selecting one second mobile terminal when there are a plurality of second mobile terminals for which the verification result of the authentication response packet is valid. do.

According to another feature of the present invention, a multi-function mobile terminal having a mobile communication function and a relay function between mobile terminals is provided. The mobile terminal of the present invention generates a pre-authentication request packet including a signature and a certificate of its own, and a pre-authentication request unit for broadcasting and a signature of the certificate and the first mobile terminal from at least one first mobile terminal receiving the authentication request packet. And a receiving unit for receiving an authentication response packet including an authentication requestor for selecting an first mobile terminal from at least one first mobile terminal that has transmitted the authentication response packet.

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. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

Now, an authentication method and a mobile terminal using the same in a multi-function mobile terminal according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a logical hybrid network according to an embodiment of the present invention.

Referring to FIG. 1, an AAA server 20 and an access station AS1 and AS2 are connected through a wireless network 10. The mobile terminals MT1 to MT4 exist in a cell served by the access station AS1, and the mobile terminals MT5 to MT8 exist in a cell served by the access station AS2. The AAA server 20 manages authentication of the mobile terminal and authentication of packets generated from the mobile terminal. Here, the mobile terminals MT1 to MT8 can communicate with the access stations 31 and 32 through the cellular interface, as well as with other mobile terminals MT1 to MT8 through the relay interface.

In order to prevent illegal packet inflow due to the existence of the illegal mobile terminal described in the prior art, each of the mobile terminals MT1 to MT8 performs packet authentication between mobile terminals.

Hereinafter, packet authentication between mobile terminals according to the first embodiment of the present invention will be described in detail with reference to FIGS. 2 and 3.

2 is a diagram illustrating the concept of a packet authentication method according to a first embodiment of the present invention. 3 is a flowchart for explaining a packet authentication method in a relay mobile terminal according to the first embodiment of the present invention, and FIG. 4 is a flowchart for explaining a packet authentication method in a destination mobile terminal.

As shown in FIGS. 2 and 3, before transmitting a packet, the mobile terminal MT9 first checks inter packet check data (hereinafter referred to as 'ICD') and end-to-end packet check data (end−). After calculating the to-end packet check data (hereinafter referred to as 'ECD'), and transmits the packet including the ICD and ECD (S31). Each time the relay mobile terminal MT8 receives a packet from the mobile terminal MT9 (S32), the relay mobile terminal MT8 calculates the ICD (S33), and compares the calculated ICD with the calculated ICD (S34). If the received ICD and the calculated ICD are the same, the relay mobile terminal MT8 sends a packet to the next mobile terminal MT5 or transmits the packet to a higher layer (S35). If the received ICD and the calculated ICD are not the same, authentication fails and the packet is discarded (S36). That is, when the mobile terminal MT9 that has transmitted the packet to the relay mobile terminal MT8 is an illegal mobile terminal, the packet is discarded in the ICD comparison of the relay mobile terminal MT8.

Referring to FIG. 4, when the mobile terminal MT6 corresponding to the packet destination receives the relayed packet (S41), the ICD is verified in the same manner as described in steps S33, S34, and S36 of FIG. S44). If the ICD and the calculated ICD of the received packet are the same, the destination mobile terminal MT6 verifies the ECD similarly to the method of verifying the ICD. That is, the destination mobile terminal MT6 calculates the ECD (S45) and compares the calculated ECD with the ECD of the received packet (S46). If the calculated ECD and the received ECD result are the same, the destination mobile terminal MT6 transmits the packet to the upper layer (s47). If the calculated ECD and the received ECD result are not the same, the packet is discarded (S48).

Network topology can change frequently in logical hybrid networks. Each time the topology changes, the affected neighboring mobile terminals must update their shared secret information. Therefore, it is better to use information such as a network key or terminal certificate without including the secret information of the neighboring mobile terminal that changes according to the topology change in the ICD. The network key is secret information, which is secret information shared by each legitimate terminal in a logical hybrid network.

Hereinafter, an ICD calculation method for authentication between mobile terminals will be described with reference to Equations 1 and 2 below.

First, the ICD calculation method using the network key is shown in Equation 1.

ICD = HK (NK, Packet_data | N)

Here, HK is a keyed hash function such as HMAC-MD5 (IETF RFC2085 standard), NK is a network key, and Packet_data | N is a time stamp for countering a packet attack or a sequence number of packet data.

That is, the ICD by the hash function is calculated using the network key and the sequence number (or time stamp) of the packet data as parameters.

Next, the ICD calculation method using the terminal certificate is shown in Equation 2.

Here, Sig # i is a signature of a mobile terminal MTi, and Cert # i is a certificate of a mobile terminal MTi provided by a certificate authority (CA). E is a public key encryption function such as RSA (Rivest Shamir Adleman), and SK # i is a secret key of a mobile terminal MTi. In addition, ID # i is an identifier of the mobile terminal MTi, PK # i is a public key of the mobile terminal MTi, LT is a life time of a certificate, and SKca is The private key of the certification authority, where H is a one-way hash function such as MD5 (a hash function in the form of a message digest algorithm).

In the ICD calculation method for authentication between mobile terminals, the network key usage method can be used for data packet verification and authentication request packet verification, and the certificate usage method also requires data packet verification and authentication request when the mobile terminal does not have a network key. Can be used for packet verification.

And the ECD calculation method for end-to-end authentication is shown in Equation 3.

ECD = HK (Kmn, packet_data | N)

Here, Kmn is an end-to-end key shared by the mobile terminals MTm and MTn.

However, since the network key NK is information shared by the legitimate mobile terminal, the network key NK is distinguished between the legal mobile terminal and the illegal mobile terminal through ICD calculation. However, when the certificate method is used, the legitimate mobile terminal does not know the private key (SK) of the other mobile terminal, and thus, the ICD calculation does not distinguish between the legal mobile terminal and the illegal mobile terminal. Therefore, in the method described in the first embodiment of the present invention, the authentication request packet cannot be authenticated when the mobile terminal does not have a network key.

Hereinafter, a pre-authentication method for processing an authentication request packet between legal mobile terminals after authenticating between legal mobile terminals using a certificate will be described with reference to FIG. 5.

5 is a diagram illustrating a concept of a pre-authentication method according to a second embodiment of the present invention, and FIG. 6 is a flowchart illustrating a pre-authentication method according to a second embodiment of the present invention.

In the second embodiment of the present invention, a mobile terminal requesting authentication first finds one legitimate mobile terminal, and then an authenticator sends an authentication request packet to the AAA server.

Specifically, the mobile terminal MT9 requesting authentication for network access from the logical hybrid network to the wireless network broadcasts a pre-authentication request (PREQ) packet for pre-authentication (S61). The PREQ packet includes an identifier (ID), a time stamp, a signature, and a certificate of the mobile terminal MT9 as shown in equation (4).

Here, ID # 9 is an identifier of the mobile terminal MT9, N is a time stamp, Sig # 9 is a signature of the mobile terminal MT9, and Cert # 9 is of a mobile terminal MT9 provided by a certification authority. Certificate. E is a public key encryption function, and SK # 9 is a private key of the mobile terminal MT9. PK # 9 is the public key of the mobile terminal MT9, LT is the validity period of the certificate, SKca is the private key of the certification authority, and H is a one-way hash function.

If the other mobile terminal MT4 has a route to the access stations AS1 and AS2 when receiving the PREQ packet, the time stamp, signature, and certificate in the packet are verified (S62). At this time, the mobile terminal MT4 queries the AAA server 20 by using the information of the mobile terminal MT9 received in the PREQ packet and a path to the existing AAA server 20 to perform verification. If the verification result is correct, the mobile terminal MT4 transmits a pre-authentication reply (prep) packet having a time stamp, its identifier and signature, and a certificate of the mobile terminal MT9 as shown in equation (5). To transmit (S63). If the verification result is incorrect, the mobile terminal MT4 discards the PREQ packet (S63a). Similarly, the mobile terminal MT8 having a route to the access stations AS1 and AS2 among the mobile terminals receiving the broadcast PREQ packet performs the procedure of step S62, S63 or S63a.

Here, ID # 4 is an identifier of the mobile terminal MT4, N is a time stamp, and Sig # 4 is a signature of the mobile terminal MT4. E is a public key encryption function, and SK # 4 is a private key of the mobile terminal MT4.

When the mobile terminal MT9 receives the PREP packet, the mobile station MT9 verifies a certificate, a signature, and a time stamp in the packet (S64). At this time, the mobile terminal MT9 performs verification by comparing whether a certificate in a field of a PREP packet is identical to a certificate it has. If the verification result is correct and the mobile terminal MT9 receives PREP packets simultaneously from the multiple mobile terminals MT4 and MT8, the mobile terminal MT4 selects one mobile terminal MT4 from the legal mobile terminals MT4 and MT8 that are successful in the verification. (S65). If the verification result is incorrect, the mobile terminal MT9 discards the PREP packet (S65a).

Next, if the verification result of the PREP packet is correct, the mobile terminal MT9 sends an authentication request and / or a route establishment request to the selected mobile terminal MT4 (S66). At this time, all packets sent to the mobile terminal MT4 include an ICD for packet authentication. In this way, if pre-authentication is performed between the legal mobile terminals, the AAA server 20 can be connected only by relaying the legal mobile terminals. Therefore, as in the prior art, all the mobile terminals that receive the authentication request packet do not request authentication to the AAA server 20, thereby reducing the load on the AAA server.

Although the data packet and the authentication request packet can be processed by the network key method or the certificate method, respectively, verifying the authentication request packet by the pre-authentication method described in FIGS. 5 and 6 can reduce the load on the AAA server 20. For example, the authentication request packet may be processed by a pre-authentication method and the data packet may be processed by a network key method. Hereinafter, an embodiment in which a data packet is verified by a network key method and an authentication request packet is verified by a pre-authentication method will be described with reference to FIG. 7.

7 is a diagram for explaining an authentication method according to a third embodiment of the present invention.

Referring to FIG. 7, when a packet arrives, the packet separator of the mobile terminal determines whether the received packet is a data packet or an authentication request packet PREQ (S71). If it is determined that the received packet is a data packet, the packet is verified using the network key method using the method described in steps S33 and S34 of FIG. 3 (S72a). If the verification result is correct, the mobile terminal determines whether the currently arrived node is the final destination (S73a). If the verification result is incorrect, the mobile terminal discards the data packet (S74a). Next, if it is not the final destination, the mobile terminal transmits the packet to the mobile terminal corresponding to the next node (S75a), and the mobile terminal verifies the ECD in the end-to-end manner described in steps S46 and S47 of FIG. 4 (S76a). ). If the ECD verification result is correct, the mobile terminal transmits the data packet to a higher layer (S77a), and if it does not match, discards the data packet (S78a).

If the packet received in the determination of step S71 is an authentication request packet PREQ, verification is performed by the method described in steps S62 to S65a of FIGS. 5 and 6 (S72b). If the verification result is correct, the selected mobile terminal selects a PREQ packet. An authentication request is received from the broadcast mobile terminal (S73b), and if the verification result is incorrect, the packet is discarded (S74b). The mobile terminal receiving the authentication request transmits the authentication request to the AAA server 20 via another mobile terminal which has been pre-authenticated in the same manner (S75b).

Further, in order to realize the authentication method described in the embodiment of the present invention, the mobile terminal according to the embodiment of the present invention includes a pre-authentication requesting unit, a receiving unit, an authentication requesting unit, an authentication response unit, a data packet verification unit, and an end-to-end packet verification. It may include wealth. Such a configuration may be implemented in software and recorded in the recording apparatus, or may be implemented in hardware.

The pre-authentication request unit generates and broadcasts a PREQ packet (see step S61 of FIG. 6), and the receiving unit receives and verifies a PREP packet transmitted from another mobile terminal (see step S64 of FIG. 6). The authentication requesting unit selects one of the mobile terminals that transmitted the PREP packet and requests authentication from the mobile terminal (see steps S65 and S66 in FIG. 6). When the authentication response unit receives the PREQ packet from another mobile terminal, the authentication response unit generates the PREP packet and transmits the generated PREP packet to the mobile terminal (see step S63 of FIG. 6). In addition, when the received packet is a data packet, the data packet verification unit calculates the ICD, compares the received ICD, and transmits the data packet to the next node or higher layer if they match (see steps S32 to S35 in FIG. 3). The end-to-end packet verification unit calculates the ECD, compares the received ECD with the received ECD when it is the final destination, and transmits the same to the higher layer (see steps S45 to S47 of FIG. 4).

Although the preferred 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.

As described above, according to the packet authentication method between mobile terminals, the influence of the denial of service attack can be reduced and the packet modification by the illegal or legal mobile terminals can be detected. In addition, according to the pre-authentication method, unnecessary authentication request packets can be reduced.

Claims (18)

In the authentication method in a multi-function mobile terminal having a mobile communication function and a relay function between mobile terminals, a) a first mobile terminal receiving a packet including first packet acknowledgment data from a second mobile terminal; b) calculating and comparing second packet acknowledgment data with the first packet acknowledgment data by the first mobile terminal; And c) if the comparison result in step b) is identical, the first mobile terminal transmits the packet received in step a) to the next node or higher layer. Including; And the first and second packet acknowledgment data are generated by information shared between legitimate mobile terminals. The method of claim 1, The packet received in step a) is a data packet. The method of claim 1, The information shared between the legitimate mobile terminal comprises a network key. The method according to any one of claims 1 to 3, The packet received in step a) further includes third packet acknowledgment data, If the first mobile terminal is the final destination mobile terminal, The authentication method, d) calculating, by the first mobile terminal, fourth packet acknowledgment data and comparing it with the third packet acknowledgment data; And e) the first mobile terminal transmitting the packet received in step a) to a higher layer if the comparison result in step d) is identical; More, And the third and fourth packet acknowledgment data are generated by information shared between legitimate end-to-end mobile terminals. The method of claim 4, wherein The information shared between the legitimate end-to-end mobile terminal comprises an end-to-end key. The method of claim 5, The information shared between the legitimate mobile terminal further includes a sequence number or time stamp of the packet received in step a), The information shared between the legitimate end-to-end mobile terminal further comprises a sequence number or time stamp of the packet received in step a). In the authentication method in a multi-function mobile terminal having a mobile communication function and a relay function between mobile terminals, Broadcasting, by a first mobile terminal, a pre-authentication request packet including information of the first mobile terminal, Receiving, by the first mobile terminal, an authentication response packet including some of the information of the first mobile terminal and information of the second mobile terminal from at least one second mobile terminal that has received the pre-authentication request packet; And And after the first mobile terminal verifies the authentication response packet, if the verification result is valid, making an authentication request to the second mobile terminal. The method of claim 7, wherein The information of the first mobile terminal includes a time stamp, an identifier of the first mobile terminal, a signature of the first mobile terminal, and a certificate of the first mobile terminal, Some of the information of the first mobile terminal includes a certificate of the first mobile terminal, The information of the second mobile terminal includes a time stamp, an identifier of the second mobile terminal and a signature of the second mobile terminal. Authentication method in a composite function mobile terminal. delete The method of claim 8, The signature of the first mobile terminal and the signature of the second mobile terminal are each generated by information including its own private key, In the multi-functional mobile terminal, the certificate of the first mobile terminal includes information generated by its identifier, public key, validity period of the certificate, and at least one of the identifier, public key and certificate and private key of the certification authority. Authentication method. The method according to claim 7 or 8, The second mobile terminal verifies the pre-authentication request packet and transmits the authentication response packet to the first mobile terminal when the verification result is valid and the second mobile terminal has a route to the access station. Authentication method in the terminal. The method according to claim 7 or 8, And selecting, by the first mobile terminal, a second mobile terminal when there are a plurality of second mobile terminals for which the verification result of the authentication response packet is valid. In the composite function mobile terminal having a mobile communication function and a relay function between mobile terminals, Pre-authentication request unit for generating and broadcasting a pre-authentication request packet including its signature and certificate A receiving unit for receiving an authentication response packet including the certificate and the signature of the first mobile terminal from at least one first mobile terminal receiving the authentication request packet; and And an authentication request unit which selects one first mobile terminal from the at least one first mobile terminal which has transmitted the authentication response packet and makes an authentication request. The method of claim 13, The pre-authentication request packet further includes its identifier and time stamp, The authentication response packet further comprises an identifier and a time stamp of the first mobile terminal. The method of claim 13, If you have a route to the access station, When the pre-authentication request packet is received from the second mobile terminal, the pre-authentication request packet is verified, and when the verification result is valid, an authentication response packet including a certificate of the second mobile terminal and its signature is generated and generated by the second mobile terminal. A composite function mobile terminal further comprising an authentication response unit for transmitting to the mobile terminal. The method of claim 15, Multifunction mobile terminal for communicating the authentication request from the second mobile terminal to the access station. The method according to any one of claims 13 to 16, When receiving a data packet including first packet acknowledgment data from a third mobile terminal, the first packet acknowledgment data of the third mobile terminal is calculated, and the calculated first packet acknowledgment data and the received first packet acknowledgment data are received. The data packet verification unit further transmits the data packet to a next node or a higher layer when is matched. And the first packet acknowledgment data is generated by information shared between legitimate mobile terminals. The method of claim 17, If you are the final destination, Second packet acknowledgment data included in a data packet that calculates second packet acknowledgment data of the third mobile terminal and includes the calculated second packet acknowledgment data and first packet acknowledgment data received from the third mobile terminal. Further includes an end-to-end packet verification unit for transmitting a data packet including the first packet acknowledgment data received from the third mobile terminal to an upper layer when M is matched, And said second packet acknowledgment data is generated by information shared between legitimate end-to-end mobile terminals.

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