JP6892846B2 - User authentication method for core network system including authentication device and service device - Google Patents

Description

The present invention relates to a user authentication technique in a core network system of IMS (IP Multimedia Subsystem).

FIG. 1 is a system configuration diagram of mobile communication in the prior art.

According to the system of FIG. 1, it is composed of the following devices.
Core network system
IMS1 (Service Core Network)
EPC (Evolved Packet Core) 3 (Packet Core Network)
Authentication database (HSS (Home Subscriber Server)) 2 (subscriber information registration)
Base station (eNB (e-Node B)) 4
Terminal (UE (User Equipment)) 5

The EPC4 accommodates a plurality of base stations and has an MME (Mobility Management Entity), an SGW (Serving-Gateway), a PGW (PDN (Packet Data Network) -Gateway) and a PCRF (Policy and Charging Rules Function).
The MME is a core network control device that communicates with a mobile terminal via a base station. The MME not only manages the movement of terminals, but also authenticates mobile terminals linked with HSS and controls the setting of IP transmission routes.
The SGW executes transmission control of IP packets based on the control from the MME.
The PGW serves as a connection point with a PDN such as the Internet or IMS, and receives all IP packets from the PDN to the mobile terminal.
The PCRF determines the IP packet transmission policy such as Quality of Service (QoS) and billing method for performing transmission quality control in PGW and SGW.

IMS performs network resource allocation and gate control, and provides IP-based calling services such as VoLTE (Voice over LTE).

IMS1 that provides VoLTE needs to hold "user authorization information (telephone number + contract service information, etc.)". Therefore, IMS1 needs to be connected to the authentication database 2.

When the terminal 5 (for example, a smartphone) possessed by the user uses the VoLTE service, the terminal 5 (for example, a smartphone) transmits a user authentication request including the identification information of the SIM card. Upon receiving the user authentication request, IMS1 collates the identification information with the authentication database 2. If the authentication is successful, the authentication information and the user authorization information are issued. After that, the terminal 5 uses the service by using the authentication information. IMS1 provides the service by confirming the user authorization information based on the authentication information received from the terminal 5.

Such a core network system has improved fault tolerance in anticipation of a power outage or communication equipment failure in the event of a large-scale disaster, for example.
However, when a failure occurs in a wireless access network (backhaul line) due to, for example, a natural disaster in a wide area, the connection from some terminals to the wide area network is cut off, resulting in an isolated communication area.

In this case, the telecommunications carrier brings a base station or a core network device having a function of connecting to a wide area network to a communication isolated area to restore communication. Since base stations and core network devices are carried by such things as automobiles, balloons, and helicopters, it takes a relatively long time before communication can actually be performed.

In addition, there is a problem in terms of cost to construct a dedicated communication business facility used only in an isolated communication area. For that purpose, there is also a technique of mounting the entire system of an existing core network device or authentication database constructed by software on portable hardware and using it as its communication business equipment (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-034470

However, even if a natural disaster or the like suddenly occurs, there is a problem in mounting an authentication database, which is personal information of a user in a communication isolated area, on a portable device. In addition, it is not possible to predict the area range in advance and register the subscriber information of the terminal staying there in the authentication database. Of course, it is not possible to pre-register all the subscriber information of mobile phone subscribers in Japan in the portable device installed in the communication isolated area.

Therefore, an object of the present invention is to provide a user authentication method for a core network system in which a terminal can use a communication service even in a communication environment in which a user authentication process based on an authentication database cannot be executed. To do.

According to the present invention, in a user authentication method of a core network system including an authentication device, a service device, and a terminal,
The authentication device holds the private key for the access token and
The service device holds the access token public key corresponding to the access token private key,
Service devices and terminals hold a common key
When the authentication device receives a user authentication request from the terminal, the first step of returning the access token to which the user authorization information based on the authentication database is signed by the private key for the access token is returned to the terminal.
If the terminal cannot communicate with the authentication device, as a second step,
The terminal encrypts the control request including the access token with the common key, and sends the encrypted control request to the service device.
The service device decrypts the encrypted control request with the common key , verifies that the access token has not been tampered with with the access token public key, decrypts the user authorization information, executes the control request, and succeeds. It is characterized in that an encryption success response in which the response is encrypted with a common key is returned to the terminal.

According to another embodiment of the user authentication method of the present invention.
The core network system is based on IMS (IP Multimedia Subsystem).
About the second step
The control request is a location registration request,
When the user authorization information is decrypted, the service device preferably creates session information and returns a success response to the terminal.

According to another embodiment of the user authentication method of the present invention.
About the first step
The eleventh step in which the authentication device holds in advance the extended response value (XRES) encrypted by the terminal private key from the random value (RAND) and transmits the random value to the terminal.
In the twelfth step, the terminal sends an access token request including an extended response value (XRES) encrypted by the terminal private key from a random value (RAND) to the authentication device.
The authentication device has a thirteenth step of setting user authorization information when the extended response value (XRES) held in advance and the extended response value (XRES) received from the terminal match.
It is also preferable that the authentication device executes the fourteenth step of returning the access token whose user authorization information is signed by the private key for the access token to the terminal.

According to another embodiment of the user authentication method of the present invention.
The authentication device and the authentication database are connected separately,
About the eleventh step
The authentication device sends a user authentication request to the authentication database and
It is also preferable that the authentication database returns a random value (RAND) and an extended response value (XRES) encrypted from the random value by the terminal private key to the authentication device.

According to another embodiment of the user authentication method of the present invention.
The authentication device holds the root certificate for TLS (Transport Layer Security) and holds it.
The service device holds the server certificate for TLS and holds the server certificate.
About the first step
The authentication device returns the root certificate to the terminal together with the access token.
About the second step
When the service device receives the TLS connection request from the terminal, it returns the server certificate to the terminal and returns it to the terminal.
It is also preferable that the terminal verifies the server certificate by the root certificate.

According to another embodiment of the user authentication method of the present invention.
The service device holds the service public key and the service private key,
About the second step
When the service device receives the TLS connection request from the terminal, the service device returns the service public key to the terminal.
The terminal generates a provisional private key, generates an encrypted provisional private key in which the provisional private key is encrypted with the service public key, transmits the encrypted provisional private key to the service device, and the provisional secret key. Create a common key from
It is also preferable that the service device decrypts the encrypted provisional private key with the service private key to acquire the provisional private key, and generates a common key from the provisional private key.

According to the present invention, in a core network system including an authentication device, a service device, and a terminal,
The authentication device holds the private key for the access token and
The service device holds the access token public key corresponding to the access token private key,
Service devices and terminals hold a common key
When the authentication device receives a user authentication request from the terminal, the authentication device returns an access token to the terminal, in which the user authorization information based on the authentication database is signed by the private key for the access token.
The terminal encrypts the control request including the access token with the common key and sends the encrypted control request to the service device.
The service device decrypts the encrypted control request with the common key , verifies that the access token has not been tampered with with the access token public key, decrypts the user authorization information, executes the control request, and succeeds. The response is encrypted with a common key, and a successful encryption response is returned to the terminal .

According to the user authentication method of the core network system of the present invention, the terminal can use the communication service even in a communication environment in which the user authentication process based on the authentication database cannot be executed.

It is a system configuration diagram of the mobile communication in the prior art. It is a system block diagram of the mobile communication in this invention. It is a basic sequence diagram in this invention. It is a detailed sequence diagram of the first step of this invention. It is a detailed sequence diagram of the 2nd step of this invention. It is a 1st sequence diagram based on the TLS connection request of this invention. It is a 2nd sequence diagram based on the TLS connection request of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a system configuration diagram of mobile communication in the present invention.

According to FIG. 2, as compared with FIG. 1, the core network system of the IMS that provides VoLTE is separated into the “authentication device 11” and the “service device 12”. Therefore, only the authentication device 11 connects to the authentication database 2.
Further, for example, in the case of assuming a natural disaster, the base station 4 may be provided with only the service device 12 as an isolated core network system constructed by software. This enables communication between the subordinate terminals 5.
That is, according to the present invention, the user of the terminal 5 can be authenticated even if the authentication database 2 is not connected to the core network system.

When the isolated core network system of the base station 4 is activated, it may be disconnected from the core network due to, for example, a disaster or a failure. Further, for example, it may be a case where the core network is intentionally cut off at a specific event venue. In this case, an isolated call service can be provided only to the user who stays at the event venue.

FIG. 3 is a basic sequence diagram in the present invention.

According to the present invention, the authentication device 11 holds an "access token private key".
In addition, the service device 12 holds an "access token public key" corresponding to the access token private key.

According to the present invention, it has the following two steps.
(S1) The authentication device 11 issues an access token to the terminal 5.
(S2) The service device 12 authenticates the user with the access token received from the terminal 5.
That is, even if the authentication database 2 is not connected to the core network system, the terminal 5 can succeed in user authentication only with the service device 12 and receive the VoLTE service.

The "access token" is the authentication information of the character string notified by the IMS to the terminal 5 after the user authentication. When the terminal 5 connects to the authentication device 11 for the first time, an access token is issued, and the terminal 5 holds the access token. After that, the terminal 5 authenticates the user by using the access token when connecting to the core network system.

JWT (JSON Web Token) may be used as an example of the access token.
<JWT format>
[HEADER]. [PAYLOAD]. [SIGNATURE]
HEADER and PAYLOAD: base64 encoding <JWT PAYLOAD example>
{
"sub": "userhoge",
"phone_number": "080-1234-5678",
"supplementary_service": "communication-diversion = true",
"aud": "audhoge",
"iss": "https://example.com/",
"exp": 1452565628,
"iat": 1452565568
}

[S1: First step]
(S11) The terminal 5 transmits a user authentication request to the authentication device 11.
(S12) The authentication device 11 acquires "user authorization information" based on the authentication database 2 (specifically, see FIG. 4).
(S13) The authentication device 11 generates an access token when the user authentication request includes an access token request. The access token is the user authorization information signed by the private key for the access token. If the user authentication request does not include the access token request, the terminal 5 operates in the existing method. In that case, every time the terminal 5 connects to the core network system, user authentication using the authentication database 2 is required.
(S14) The authentication device 11 returns the access token to the terminal 5.
As a result, the terminal 5 can hold the access token.

[S2: Second step]
(S21) Next, the terminal 5 transmits a control request including an access token to the service device 12.
(S22) The service device 12 verifies non-tampering with the access token public key from the access token, and then decrypts the user authorization information.
(S23) The service device 12 executes the control request as the authentication is successful.
As a result, as the core network system, the user of the terminal 5 can be authenticated only by the service device 12.

FIG. 4 is a detailed sequence diagram of the first step of the present invention.

According to FIG. 4, both the terminal 5 and the authentication database 2 hold the “terminal private key”. Further, the authentication device 11 communicates with the separately connected authentication database 2.

(S11) The terminal 5 transmits a user authentication request to the authentication device 11. When the terminal 5 supports the access token method, the user authentication request includes the access token request.
(S111) The authentication device 11 transmits a user authentication request to the authentication database 2.
(S112) The authentication database 2 generates a random value (RAND).
(S113) Further, the authentication database 2 generates an extended response value (XRES) encrypted by the terminal private key from the random value (RAND).
(S114) The authentication database 2 responds to the authentication device 11 with a random value (RAND) and an extended response value (XRES).
(S115) The authentication device 11 holds the extended response value (XRES) by itself and responds to the terminal 5 with a random value (RAND).
(S116) The terminal 5 generates an extended response value (XRES) encrypted by the terminal private key from the random value (RAND).

(S121) The terminal 5 transmits an access token request including an extended response value (XRES) to the authentication device 11.
(S122) The authentication device 11 determines whether or not the extended response value (XRES) held in advance matches the extended response value (XRES) received from the terminal 5.
(S123) If the authentication device 11 matches according to S122, the authentication device 11 transmits a user authentication success notification to the authentication database 2.
(S12) The authentication database 2 notifies the authentication device 11 of the "user authorization information". As a result, the authentication device 11 holds the user authorization information for the terminal 5.
(S13) The authentication device 11 generates an access token. The AX token is the user authorization information signed by the private key for the access token.
(S14) The authentication device 11 returns a success response including the generated access token to the terminal 5.
As a result, the terminal 5 holds the access token.

FIG. 5 is a detailed sequence diagram of the second step of the present invention.

(S21) The terminal 5 transmits a location registration request as a control request to the service device 12.
(S22) The service device 12 verifies the non-tampering with the access token public key from the access token, and then decrypts the user authorization information.
(S23) The service device 12 creates session information.
(S24) Then, the service device 12 returns a success response including the session information to the terminal 5.

(S31) The terminal 5 transmits a transmission request including an access token to the service device 12.
(S32) The service device 12 verifies that the access token has not been tampered with by the access token public key.
(S33) After the non-tampering is verified, the service device 12 transmits the transmission request to another node.
(S34) It is assumed that the service device 12 receives a transmission notification to the terminal 5 from another node. The non-tampering of the access token from the terminal 5 has already been verified.
(S35) Then, the service device 12 returns the outgoing notification and the success response including the terminal 5 session information to the terminal 5.

In the case of FIG. 5, regarding S35, the terminal 5 cannot identify whether or not the transmission notification is sent from the reliable IMS service device 12. Therefore, it is preferable to use SIP over TLS.
In the existing method, the packet source can be verified at the time of packet reception by establishing IPsec between the terminal and IMS. However, since the IP address of the IMS is notified from the PGW at the time of attachment, it is unlikely that the terminal will connect to an unreliable IMS.

FIG. 6 is a first sequence diagram based on the TLS connection request of the present invention.

According to FIG. 6, the authentication device 11 further holds a "root certificate" for TLS (Transport Layer Security).
In addition, the service device 12 holds a "server certificate" for TLS, a "service public key", and a "service private key".

(S11) The terminal 5 transmits a user authentication request to the authentication device 11.
(S12 to S13) For example, the sequence of FIG. 4 described above is executed.
(S14) The authentication device 11 returns a success response including the root certificate to the terminal 5 together with the access token.
As a result, the terminal 5 holds the access token and the root certificate.

(S201) The terminal 5 transmits the TLS connection request to the service device 12.
(S202) The service device 12 returns the server certificate and the service public key to the terminal 5.
(S203) The terminal 5 verifies that the server certificate has not been tampered with with the root certificate.
(S204) The terminal 5 generates a provisional private key.
(S205) The terminal 5 generates an encrypted provisional private key in which the provisional private key is encrypted by the service public key.
(S206) The terminal 5 transmits the encrypted provisional private key to the service device 12.
(S207) The terminal 5 creates a common key from the provisional private key.

(S208) The service device 12 decrypts the encrypted provisional secret key with the service secret key to acquire the provisional secret key.
(S209) The service device 12 creates a common key from the provisional private key.
As a result, both the terminal 5 and the service device 12 can create a common key.

FIG. 7 is a second sequence diagram based on the TLS connection request of the present invention.

(S20) The terminal 5 encrypts the location registration request (control request) including the access token with the common key.
(S21) The terminal 5 transmits an encrypted location registration request to the service device 12.
(S220) The service device 12 decrypts the encrypted location registration request with the common key.
(S22) The service device 12 verifies the non-tampering from the access token with the access token public key, and then decrypts the user authorization information.
(S23) The service device 12 creates session information.
(S240) The service device 12 encrypts the success response including the session information with the common key.
(S24) The service device 12 returns an encrypted success response to the terminal 5.

According to the above-described embodiment, the EPC / IMS network has been described, but it can also be applied to an existing 3G (Third Generation) mobile communication system and a future 5G (5th Generation) mobile communication system.

As described in detail above, according to the user authentication method of the core network system of the present invention, the terminal uses the communication service even in a communication environment in which the user authentication process based on the authentication database cannot be executed. be able to.

According to the present invention, the service device 12 can be shared, for example, by sharing the access token verification public key between different telecommunications carriers. Further, by passing the access token between the terminals, it is possible to use the VoLTE service of different telecommunications carriers regardless of the presence or absence of the SIM card.

With respect to the various embodiments of the present invention described above, various changes, modifications and omissions within the scope of the technical idea and viewpoint of the present invention can be easily made by those skilled in the art. The above explanation is just an example and does not attempt to restrict anything. The present invention is limited only to the scope of claims and their equivalents.

11 Authentication device 12 Service device 2 Authentication database 3 EPC
4 base stations 5 terminals

Claims (7)

In the user authentication method of the core network system including the authentication device, the service device, and the terminal,
The authentication device holds the private key for the access token and
The service device holds the access token public key corresponding to the access token private key, and holds the access token public key.
Service devices and terminals hold a common key
When the authentication device receives the user authentication request from the terminal, the first step is to return the access token to which the user authorization information based on the authentication database is signed by the private key for the access token to the terminal. ,
When the terminal cannot communicate with the authentication device, as a second step,
The terminal encrypts the control request including the access token with the common key, and transmits the encrypted control request to the service device.
The service device decrypts the encrypted control request with the common key , verifies that the access token has not been tampered with with the access token public key, decrypts the user authorization information, executes the control request, and executes the control request . An encryption method in which a success response is encrypted with a common key . A user authentication method characterized in that a success response is returned to a terminal. The core network system is based on IMS (IP Multimedia Subsystem).
About the second step
The control request is a location registration request.
The user authentication method according to claim 1, wherein the service device creates session information and returns a success response to the terminal when the user authorization information is decrypted. About the first step
The eleventh step in which the authentication device holds in advance the extended response value (XRES) encrypted by the terminal private key from the random value (RAND) and transmits the random value to the terminal.
A twelfth step in which the terminal transmits an access token request including an extended response value (XRES) encrypted by the terminal private key from the random value (RAND) to the authentication device.
The authentication device has a thirteenth step of setting user authorization information when the extended response value (XRES) held in advance and the extended response value (XRES) received from the terminal match.
The authentication device according to claim 1 or 2, wherein the authentication device executes the fourteenth step of returning the access token whose signature is given to the user authorization information by the private key for the access token to the terminal. User authentication method. The authentication device and the authentication database are connected separately,
About the eleventh step
The authentication device sends the user authentication request to the authentication database,
The third aspect of claim 3, wherein the authentication database returns a random value (RAND) and an extended response value (XRES) encrypted from the random value by the terminal private key to the authentication device. User authentication method. The authentication device holds the root certificate for TLS (Transport Layer Security) and holds it.
The service device holds the server certificate for TLS and holds the server certificate.
About the first step
The authentication device returns the root certificate together with the access token to the terminal.
About the second step
When the service device receives the TLS connection request from the terminal, the service device returns the server certificate to the terminal.
The user authentication method according to any one of claims 1 to 4, wherein the terminal verifies the server certificate with the root certificate. The service device holds the service public key and the service private key,
About the second step
When the service device receives the TLS connection request from the terminal, the service device returns the service public key to the terminal.
The terminal generates a provisional private key, generates an encrypted provisional private key in which the provisional private key is encrypted by the service public key, transmits the encrypted provisional private key to the service device, and the provisional secret key. Create a common key from the private key and
Claims 1 to 5, wherein the service device decrypts the encrypted provisional private key with the service private key, acquires the provisional secret key, and generates a common key from the provisional private key. The user authentication method according to any one item. In a core network system that includes an authentication device, a service device, and a terminal
The authentication device holds the private key for the access token and
The service device holds the access token public key corresponding to the access token private key, and holds the access token public key.
Service devices and terminals hold a common key
When the authentication device receives the user authentication request from the terminal, the authentication device returns the access token to which the user authorization information based on the authentication database is signed by the private key for the access token to the terminal.
The terminal encrypts a control request including the access token with a common key, and transmits the encrypted control request to a service device.
The service device decrypts the encrypted control request with the common key , verifies that the access token has not been tampered with with the access token public key, decrypts the user authorization information, executes the control request, and executes the control request . An encrypted success response that is encrypted with a common key . <br /> A core network system that returns a success response to a terminal.

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