User authentication system and user authentication method

Abstract

To enhance a phishing measurement in a user authentication based on an identify of a user terminal.SOLUTION: A user terminal generates a public key and a secret key, and transmits the public key and a transmission request of a SMS message to a server. The server stores the public key to be received in a storage part, transmits the SMS message containing an URL containing a character string for calling an application and a character string using an encryption to a destination of a telephone number of a user previously registered to an objective service in accordance with the transmission request of the SMS message to be received. The user terminal callings the application when an operation that the URL contained in the SMS message is clicked is received. The user terminal encrypts the character string for the encryption contained in the URL by using the secret key. An encryption message containing the character string to be encrypted is transmitted to the server. It is determined that a user authentication is in success when the server decode the encryption message to be received, and the decoding is in success.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a user authentication system and a user authentication method. [Background technology]

[0002] Conventionally, there has been known a mobile banking service system that performs identity verification based on information sent from a mobile terminal, in which the server sends a program to the mobile terminal that has been given specific identification information attached to it, and when the program is started, it sends the given identification information back to the server, thereby verifying the identity of the user without requesting the user to enter a password (Patent Document 1).

[0003] In addition, a technology is known that authenticates a user terminal device by comparing the device ID sent to the payment server when the user terminal device accesses the login screen of a payment app or web payment service with the device ID sent to the payment server when the user clicks on a URL listed in an SMS notification (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-22255 A [Patent Document 2] Patent No. 7202500 Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional technology, there is room for improvement in preventing phishing through user authentication based on the identity of the user terminal.

[0006] An object of the present invention is to provide a user authentication system and a user authentication method that can strengthen measures against phishing in user authentication based on the identity of a user terminal. [Means for solving the problem]

[0007] In order to achieve the above object, a user authentication system according to a first invention is a user authentication system comprising a user terminal in which an application for providing a target service is registered and a server connected to each other via a communication network so as to be able to communicate with each other, and in which the server authenticates the user who uses the user terminal, wherein the user terminal generates a public key and a private key, and transmits the public key and a request to send an SMS message to the server, the server stores the received public key in a memory unit, and in response to the received request to send an SMS message, transmits an SMS message including a string for invoking the application and a URL including a string for encryption, to a telephone number of the user pre-registered in the target service, and when the user terminal accepts an operation to click on the URL included in the SMS message or when it reads the URL included in the SMS message, it invokes the application, the user terminal encrypts the string for encryption included in the URL using the private key, and transmits an encrypted message including the encrypted string to the server, the server decrypts the received encrypted message with the public key, and determines that user authentication has been successful if the decryption is successful.

[0008] In this way, the server sends an SMS message to the user's phone number, including a string for calling the application and a URL including a string for encryption, and when the user terminal accepts an operation to click on the URL included in the SMS message or reads the URL included in the SMS message, it calls up the application and encrypts the string for encryption included in the URL using the private key, and sends an encrypted message including the encrypted string to the server, which then decrypts the received encrypted message using the public key to perform user authentication. This makes it possible to strengthen phishing countermeasures in user authentication based on the identity of the user terminal.

[0009] A user authentication method according to a second invention is a user authentication method in a user authentication system in which a user terminal in which an application for providing a target service is registered and a server are connected to each other via a communication network so as to be able to communicate with each other, and the server authenticates the user who uses the user terminal, wherein the user terminal generates a public key and a private key, and transmits the public key and a request to send an SMS message to the server, the server stores the received public key in a memory unit, and in response to the received request to send an SMS message, transmits an SMS message to a telephone number of the user pre-registered in the target service, the SMS message including a string for calling the application and a URL including a string for encryption, the user terminal invokes the application when it accepts an operation to click on the URL included in the SMS message or when it reads the URL included in the SMS message, the user terminal encrypts the string for encryption included in the URL using the private key, and transmits an encrypted message including the encrypted string to the server, the server decrypts the received encrypted message using the public key, and determines that user authentication is successful if the decryption is successful. Effect of the Invention

[0010] As described above, the user authentication system and method of the present invention have the effect of strengthening phishing countermeasures in user authentication based on the identity of a user terminal. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing a configuration of a user authentication system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic block diagram of an example of a computer functioning as a server and a user terminal according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a block diagram showing a configuration of a server according to an embodiment of the present invention. [Figure 4] FIG. 2 is a block diagram showing a user terminal according to an embodiment of the present invention. [Diagram 5] FIG. 1 is a diagram for explaining an overview of user authentication. [Figure 6] 13A and 13B are diagrams illustrating an example of a screen requesting authentication SMS transmission and an example of an SMS message. [Figure 7] FIG. 4 is a sequence diagram showing processing in the user authentication system according to the embodiment of the present invention. [Figure 8] FIG. 1 is a diagram for explaining a method for preventing phishing attacks. [Figure 9] FIG. 1 illustrates an example of a phishing attack. [Figure 10] FIG. 1 is a diagram illustrating an example of the flow of a phishing attack. [Figure 11] FIG. 1 illustrates an example of a successful phishing attack in a conventional telephone authentication method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0013] [Outline of the embodiment of the present invention] There have been cases of fraudulent transfers caused by phishing attacks that imitate online banking service sites. Some of these attacks involve spoofing by stealing authentication information during the initial registration (hereinafter referred to as activation) of banking apps.

[0014] Here, the following first to fourth authentications are examples of authentications performed when activating a banking application.

[0015] First authentication: Login password Second authentication: Verification number (the serial number on the back of your cash card) 3rd authentication: Cash card PIN 4th authentication: Authentication code (currently a one-time, disposable six-digit number sent to the registered notification phone number)

[0016] In addition, the following are some of the risks that authentication codes may be obtained fraudulently:

[0017] First, when using email as a means of transmission, there is a risk of authentication information leaks for the email service. If the authentication information for logging in to a registered webmail service is leaked, there is a risk that a malicious third party could eavesdrop on the user's email and steal the authentication code.

[0018] In addition, when using telephone as a transmission method, there is a risk of call forwarding services, where a malicious third party may set up a phone number registered by a legitimate user to be forwarded to their own phone number, and steal the authentication code.

[0019] Additionally, there is a risk of phishing (fraudulent acquisition of authentication codes) regardless of the means of transmission (SMS, phone call, email, etc.). A malicious third party may set up a phishing site and use phishing emails to lure legitimate users into entering their authentication information, which can then be stolen.

[0020] Possible methods for sending the authentication code include SMS, telephone, and email, but regardless of the method used, the authentication code is "typeable text information," so if a user is deceived, there is a risk that a malicious third party will obtain the code.

[0021] The flow of events that occur when a user is phished, activation is spoofed, and fraudulent remittance is made is explained using Figure 9.

[0022] In step S1, the criminal sends a phishing email or the like directing the victim to a fake website.

[0023] In step S2, the user, unaware that the site is fake, enters authentication information other than the authentication code.

[0024] In step S3, the perpetrator impersonates the user using the stolen authentication information and begins activating the online banking application on the smartphone.

[0025] In step S4, an authentication code is issued to the authorized contact by email, SMS, phone call, etc. The authentication code is, for example, a one-time code (six digits) sent to a contact registered in advance in the account to link the terminal with the activation.

[0026] In step S5, the user enters the authentication code into the phishing site.

[0027] In step S6, the criminal immediately uses the authentication code to complete activation and then carries out the fraudulent transfer.

[0028] We will also explain the flow of a phishing attack aimed at registering fraudulent smartphone applications using Figures 10 and 11.

[0029] FIG. 10 illustrates an example of a successful phishing attack when using telephone authentication.

[0030] First, in step S11, an attacker creates a phishing site.

[0031] In step S12, an attacker sends a phishing email.

[0032] In step S13, the user accesses a phishing site.

[0033] In step S14, the user inputs login information into the phishing site (see FIG. 11(A)). At this time, the login information is stolen.

[0034] In step S15, an attacker performs an unauthorized login to a user's account (see FIG. 11(F)).

[0035] In step S16, an attacker illegally registers an application on the smartphone.

[0036] In step S17, the user receives the authentication code by telephone (see FIG. 11(D)).

[0037] In step S18, the user inputs the authentication code into the phishing site (see FIGS. 11(B), (C), and (E)). At this time, the authentication code is stolen.

[0038] In step S19, the attacker completes the registration of the smartphone application (see FIG. 11(H)).

[0039] In step S20, an attacker carries out a fraudulent transfer.

[0040] In this way, the attack is successful when the victim enters the authentication code provided over the phone into a fake site, and the authentication code is stolen.

[0041] Additionally, it is common for authentication to be performed by receiving an authentication code as text information, such as a six-digit number, via email or SMS, and then entering the code.

[0042] The reason for authentication using an authentication code during activation is to ensure that the user registering the app is a legitimate user whose contact information is registered in the account.

[0043] Therefore, in this embodiment, a method that is effective in reducing the risk of the above-mentioned "risk of the authentication code being illegally obtained" is used. That is, by making it so that the authentication code (copyable character string information) is not input, the customer is prevented from inputting the authentication code into a phishing site by himself / herself.

[0044] Specifically, an SMS message is sent to a telephone number that the user has registered in association with a financial account, and the user is prompted to click on a URL in the SMS message.

[0045] The system then verifies the identity of the device that requested the SMS transmission and the device that received the SMS. Public key cryptography is used as a means of verifying identity.

[0046] [System Configuration] As shown in FIG. 1, a user authentication system 100 according to an embodiment of the present invention includes a server 10 and a user terminal 20.

[0047] The server 10 and the user terminal 20 are connected via a network 26 such as the Internet. The network 26 is an example of a communication network.

[0048] The user terminal 20 is composed of a mobile terminal or a computer terminal, etc., and has a function of sending and receiving SMS (Short Message Service) messages. Here, the mobile terminal includes a smartphone terminal, a mobile phone, a PDA (Personal Digital Assistants) terminal, etc. The computer terminal includes a notebook type computer terminal, a desktop type computer terminal, etc.

[0049] FIG. 2 is a block diagram showing the hardware configuration of the server 10 and the user terminal 20 of this embodiment.

[0050] 2, the server 10 and the user terminal 20 have a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a storage 14, an input unit 15, a display unit 16, and a communication interface (I / F) 17. Each component is connected to be able to communicate with each other via a bus 19. The storage 14 of the server 10 is an example of a memory unit.

[0051] The CPU 11 is a central processing unit, and executes various programs and controls each part. That is, the CPU 11 reads a program from the ROM 12 or the storage 14, and executes the program using the RAM 13 as a working area. The CPU 11 controls each of the above components and performs various arithmetic processing according to the program stored in the ROM 12 or the storage 14. In this embodiment, the ROM 12 or the storage 14 stores a program for performing various processing.

[0052] The ROM 12 stores various programs and various data. The RAM 13 temporarily stores programs or data as a working area. The storage 14 is configured with an HDD (Hard Disk Drive) or an SSD (Solid State Drive) and stores various programs including an operating system and various data.

[0053] The input unit 15 includes a pointing device such as a mouse, and a keyboard, and is used to perform various input operations.

[0054] The display unit 16 is, for example, a liquid crystal display, and displays various information. The display unit 16 may function as the input unit 15 by adopting a touch panel system.

[0055] The communication interface 17 is an interface for communicating with other devices, and uses standards such as Ethernet (registered trademark), FDDI, and Wi-Fi (registered trademark).

[0056] Next, a description will be given of the functional configuration of the server 10 and the user terminal 20. Fig. 3 is a block diagram showing an example of the functional configuration of the server 10. Fig. 4 is a block diagram showing an example of the functional configuration of the user terminal 20.

[0057] Functionally, the server 10 includes a key acquisition unit 30, a message transmission unit 32, and an authentication unit 34, as shown in FIG.

[0058] 4, the user terminal 20 functionally comprises a key generation unit 40, a transmission request unit 42, a reception unit 44, and an encryption unit 46. An online bank application for providing an online bank service as an example of a target service is registered in the user terminal 20, and the key generation unit 40, the transmission request unit 42, and the encryption unit 46 are realized as functions of the online bank application.

[0059] The key generation unit 40 of the user terminal 20 generates a pair of a public key and a private key (see FIG. 5).

[0060] The transmission request unit 42 transmits to the server 10 a request to transmit an SMS message, including the generated public key.

[0061] For example, as shown in FIG. 6, after the first authentication, second authentication, and third authentication are successful, when a press of the “Send Authentication SMS” button displayed on the display unit 16 of the user terminal 20 is received, the transmission request unit 42 transmits a request to send an SMS message including the public key to the server 10 (see FIG. 5).

[0062] The key acquisition unit 30 of the server 10 stores the received public key in the storage 14. In response to the received SMS message transmission request, the message transmission unit 32 calls an online bank application and transmits an SMS message including a URL including a character string for encryption to the telephone number of the user preregistered in the online bank service (see FIG. 5).

[0063] Here, an example of a phone number is a mobile phone number registered to a financial account.

[0064] When the accepting unit 44 of the user terminal accepts the operation of clicking on the URL included in the SMS message, it calls up an online bank application.

[0065] For example, as shown in FIG. 6, a click operation on a URL in an SMS message displayed on the display unit 16 of the user terminal 20 is accepted.

[0066] The encryption unit 46 encrypts the character string for encryption included in the URL using the private key, and transmits an encrypted message including the encrypted character string to the server 10 (see FIG. 5).

[0067] The authentication unit 34 of the server 10 decrypts the received encrypted message with the public key, and if the decryption is successful, it determines that the user authentication has been successful (see FIG. 5).

[0068] [User authentication system function] Next, the operation of the user authentication system 100 according to the embodiment of the present invention will be described.

[0069] First, an online bank application is registered in the user terminal 20. When an instruction to start the online bank application is received by a user operating the user terminal 20, the sequence shown in Fig. 7 is started. This sequence is an example of a user authentication method.

[0070] In step S100, an online bank application is launched in the user terminal 20, and a screen transition process for transitioning the screen of the online bank application is performed on the server 10. Then, data of a login screen is transmitted from the server 10 to the user terminal 20, and the login screen is displayed on the user terminal 20.

[0071] In the next step S102, the user terminal 20 accepts the account number and login password entered on the login screen, and upon accepting an authentication execution request, transmits the authentication execution request including the account number and login password to the server 10.

[0072] In step S104, the server 10 performs authentication processing using the account number and login password included in the authentication execution request, and transmits the authentication result to the user terminal 20.

[0073] Then, in step S106, when the user terminal 20 accepts a request to send a message for SMS authentication, in step S108, the user terminal 20 generates a pair of a private key and a public key, and transmits the generated public key and a request to send an authentication code to the server 10.

[0074] In step S110, server 10 stores the received public key in storage 14. Then, in step S112, message sending unit 32 in server 10 calls an online bank application and sends an SMS message including a URL including an authentication code for encryption to a mobile phone number previously registered for the user's financial account.

[0075] In step S114, the accepting unit 44 in the user terminal 20 accepts an operation of clicking on the URL included in the SMS message, and in step S116, the user terminal 20 calls up an online bank application.

[0076] Then, in step S118, in the user terminal 20, the encryption unit 46 encrypts the encryption authentication code included in the URL using the private key generated in step S108 above, and transmits an encrypted message including the encrypted string to the server 10.

[0077] In step S120, the authentication unit 34 of the server 10 decrypts the received encrypted message with the public key, and if the decryption is successful, it determines that the user authentication is successful and returns the authentication result to the user terminal 20. This completes the user authentication when registering the online bank application to the user terminal 20.

[0078] As described above, according to the user authentication system of the embodiment of the present invention, the server sends an SMS message to the user's phone number, which includes a string for calling an application and a URL including a string for encryption, and when the user terminal accepts an operation of clicking on the URL included in the SMS message, the server calls the application, encrypts the string for encryption included in the URL using a private key, and sends an encrypted message including the encrypted string to the server, which then decrypts the received encrypted message using a public key to perform user authentication. This makes it possible to strengthen phishing countermeasures in user authentication based on the identity of the user terminal.

[0079] For example, as shown in Figure 8, a user enters login information into a phishing site, the login information is stolen, and an attacker illegally logs into the user's account and requests the sending of an SMS message. The SMS message is displayed on the user's device, and when the user clicks on the URL included in the SMS message, an application is launched, the encryption string included in the URL is encrypted using the private key, and an encrypted message including the encrypted string is sent to the server. At this time, the server cannot decrypt the received encrypted message using the public key, resulting in an authentication error and preventing the attacker from completing the registration of the application.

[0080] In the above embodiment, the service provided by the application is an online banking service, but this is not limited to this, and the application may provide a financial service other than an online banking service.

[0081] Furthermore, the above-mentioned server processing may be distributed and executed by a plurality of computers connected via a network.

[0082] Furthermore, in the above embodiment, an example was described in which an application is called when the user terminal accepts an operation of the user clicking on a URL included in an SMS message, but this is not limited to this, and a user terminal that receives an SMS message may automatically load the URL and automatically call the application without the user having to click on the URL. [Explanation of symbols]

[0083] 10 Server 11 CPU 14. Storage 15 Input section 16 Display 17 Communication Interface 19 Bus 20 User terminal 26 Network 30 Key acquisition part 32 Message sending section 34 Authentication Section 40 Key generation section 42 Transmission request section 44 Reception Department 46 Encryption section 100 User Authentication System

Claims

1. A user terminal in which an application for providing a target service is registered and a server are connected to each other via a communication network so as to be able to communicate with each other; A user authentication system for authenticating a user who uses the user terminal by the server, comprising: the user terminal generates a public key and a private key and transmits the public key and a request to transmit an SMS message to the server; The server stores the received public key in a storage unit, and in response to the received SMS message transmission request, transmits an SMS message including a character string for calling the application and a URL including a character string for encryption to a telephone number of the user pre-registered in the target service; When the user terminal receives an operation of clicking the URL included in the SMS message or reads the URL included in the SMS message, the application is called; the user terminal encrypts an encryption character string included in the URL using the private key, and transmits an encrypted message including the encrypted character string to the server; The server decrypts the received encrypted message with the public key, and if the decryption is successful, determines that the user authentication is successful. User authentication system.

2. 2. The user authentication system of claim 1, wherein the telephone number is a telephone number registered for a financial account.

3. 2. The user authentication system according to claim 1, further comprising: authenticating the user when the application is registered in the user terminal.

4. A user terminal in which an application for providing a target service is registered and a server are connected to each other via a communication network so as to be able to communicate with each other; A user authentication method in a user authentication system in which a server authenticates a user who uses the user terminal, comprising: the user terminal generates a public key and a private key and transmits the public key and a request to transmit an SMS message to the server; The server stores the received public key in a storage unit, and in response to the received SMS message transmission request, transmits an SMS message including a character string for calling the application and a URL including a character string for encryption to a telephone number of the user pre-registered in the target service; When the user terminal receives an operation of clicking the URL included in the SMS message or reads the URL included in the SMS message, the application is called; the user terminal encrypts an encryption character string included in the URL using the private key, and transmits an encrypted message including the encrypted character string to the server; The server decrypts the received encrypted message with the public key, and if the decryption is successful, determines that the user authentication is successful. The user authentication method.

Images