User equipment, authentication system and operation method using NFC

Abstract

An operating method of a user device that performs near field communication (NFC) with a card reader, comprising: downloading a service certificate of a service provided by a card reader from a service authentication server via a network, sending status information of the user device to the card reader, receiving a service identifier (ID) sent by the card reader depending on the status information, performing an authentication process with the card reader based on a symmetric key when the service ID exists in the downloaded service certificate, and sending an authentication success message to the card reader when the authentication process succeeds.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Korean Patent Application No. 10-2019-0135328 filed on October 29, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Example embodiments of the inventive concepts described herein relate to electronic devices. For example, at least some example embodiments relate to user devices, authentication systems, and / or methods of operating the user devices and authentication systems using near field communication (NFC). Background Art

[0004] With the development of mobile communication technology, electronic devices such as user equipment can provide various data communication functions and call functions. For example, electronic devices can provide network-based communication services, such as music services, video services, digital broadcast services, wireless Internet, short message services (SMS), multimedia messaging services (MMS), etc. In addition, electronic devices can provide services using NFC, as well as network-based communication services. For example, electronic devices can use NFC to provide payment services, transportation services, smart card (e.g., pass or employee ID card) services, etc.

[0005] The security service provided by a user device (such as a mobile phone) using NFC is available only when the user is observing the user device. For example, when the display of the user device is turned on, the user can use the iris recognition function or fingerprint recognition function of the user device. However, conventionally, for example, when the user is not paying attention to the user device, the security of the user device is vulnerable to malicious attacks or hacker attacks through NFC. Summary of the invention

[0006] Example embodiments of the inventive concept provide a user device, an authentication system, and an operating method of the user device and the authentication system, wherein the user device can perform secure authentication without user intervention even in an inactive state of the user device using NFC communication.

[0007] According to an example embodiment, a method for operating a user device that performs near field communication (NFC) with a card reader includes: storing a service certificate downloaded from a service authentication server via a network; sending status information of the user device to the card reader; selectively receiving a service identifier (ID) from the card reader based on the status information; in response to a service ID from the card reader corresponding to a service certificate stored in the user device, performing an authentication process with the card reader based on a symmetric key; and in response to a success of the authentication process, sending an authentication success message to the card reader.

[0008] According to an example embodiment, a user device includes: a host device configured to generate status information indicating an active state or an inactive state; and an NFC device configured to store a service certificate and perform NFC communication with a reader based on the status information by sending the status information to the reader and performing an authentication process with the reader based on whether a service ID received from the reader corresponds to the service certificate stored in the NFC device when the status information corresponds to an inactive state.

[0009] According to an example embodiment, an authentication system includes: a card reader configured to register a service certificate at a service authentication server; and a user device configured to store a service certificate downloaded from the service authentication server via a network, send status information of the user device to the card reader in a state where NFC communication with the card reader is possible, and when the status information corresponds to an inactive state, perform an authentication process with the card reader based on the service certificate. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other objects and features of exemplary embodiments of the inventive concepts will become apparent by describing in detail exemplary embodiments of the inventive concepts with reference to the attached drawings.

[0011] Figure 1 is a block diagram illustrating an authentication system for a user equipment according to an exemplary embodiment of the inventive concept.

[0012] Figure 2 is a diagram showing an example embodiment according to the present invention. Figure 1 Block diagram of a configuration of a user equipment.

[0013] Figure 3 It is shown in detail Figure 2 Block diagram of the security block.

[0014] Figure 4 It is shown Figure 2 Block diagram of the configuration of the NFC block.

[0015] Figure 5 is a diagram illustrating a method of registering and downloading a service certificate of the present inventive concept.

[0016] Figure 6 is a diagram illustrating an authentication process between a card reader and a user device according to the present inventive concept.

[0017] Figure 7 It is shown in detail Figure 6 FIG. 1 is a diagram of operation S130 .

[0018] Figure 8 It is shown Figure 6 and Figure 7 Flowchart of the authentication operation of the card reader shown in .

[0019] Fig. 9 is described in detail by Figure 8 Flow chart of operation S250 performed by the card reader.

[0020] Fig.10 It is shown Figure 6 and Figure 7 Flow chart of the authentication operation of the user equipment shown in .

[0021] Fig.11 It is shown Fig.10 Flow chart of operation S380. DETAILED DESCRIPTION

[0022] It should be understood that both the foregoing general description and the following detailed description are provided as examples and should be considered to provide additional description. The reference numerals will be specifically indicated in the example embodiments of the inventive concept, examples of which are shown in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and the specification to refer to the same or similar parts.

[0023] Hereinafter, exemplary embodiments of the inventive concept will be described in detail and clearly to the extent that a person having ordinary skill in the art can easily realize the inventive concept.

[0024] Figure 1 is a block diagram illustrating an authentication system including a device using near field communication (NFC) according to an example embodiment of the inventive concept.

[0025] refer to Figure 1 The authentication system includes a user device 1000, a card reader 2000 and a service authentication server 3000.

[0026] User device 1000 may be an electronic device including an NFC card chip. For example, user device 1000 may be a mobile terminal capable of supporting one or more NFC functions (such as an NFC payment function). Generally, user device 1000 may use NFC to perform payment or communication. Generally, in the case of using NFC to perform payment or communication, an application executed by a user is driven, and the application is used in an active state in which the display (or screen) is turned on. However, when the power of user device 1000 is turned off or user device 1000 is not used within a given time, the display of user device 1000 may be turned off or may enter a power saving mode. This state is referred to as the "inactive state" of user device 1000.

[0027] The security of the user device 1000 using NFC is premised on the observation of the user device 1000. The reason is that although the NFC-based payment or communication operation is performed in the active state where the user observes the display of the user device 1000, the user can still perceive various NFC-based payment or communication operations. However, in the inactive state where the display of the user device 1000 is turned off, the security of the user device 1000 is not defined in detail in the NFC protocol. On the contrary, in one or more example embodiments, the user device 1000 of the present invention may send state information SI indicating the active or inactive state of the user device 1000 to the card reader 2000. In the inactive state, the user device 1000 may perform an authentication process with the card reader 2000 by using a pre-downloaded service certificate SC. The service certificate SC may be pre-registered at the service authentication server 3000 by the card reader 2000 or a provider, and may be downloaded to the user device 1000 by the user.

[0028] The card reader 2000 can communicate with the user device 1000 in a contactless manner through NFC. By using NFC, the card reader 2000 can perform the following functions with the user device 1000: contactless mobile payment, personal authentication and / or data exchange. An example embodiment of the inventive concept will be described based on an example in which the card reader 2000 provides a service such as mobile payment. However, the example embodiments are not limited thereto.

[0029] The card reader 2000 may first register a service certificate SC at the service authentication server 3000 to support the authentication function in the inactive state conceived by the present invention. For example, the card reader 2000 may be a terminal that provides a contactless mobile payment service, such as a transit smart card (or transit card). In order to provide security performance for the user device 1000, the card reader 2000 or a provider that operates the card reader 2000 may register a service certificate SC at the service authentication server 3000. The service certificate SC may include a service identifier (ID) and a public key of the card reader 2000.

[0030] When the user device 1000 storing the service certificate SC is close to the card reader 2000 and within a given distance, the user device 1000 and the card reader 2000 may attempt to communicate (e.g., technical communication). For example, when mutual hardware identification is performed between the user device 1000 and the card reader 2000, the user device 1000 sends state information SI to the card reader 2000.

[0031] In the case where the card reader 2000 recognizes that the state information SI indicates an active state, the card reader 2000 may assume that the user is currently able to observe the user device 1000. In this case, the user device 1000 and the card reader 2000 may immediately perform NFC protocol communication without an authentication process. In the above case, authentication may be performed by specific authentication hardware (e.g., an iris recognition or fingerprint recognition device) included in the user device 1000.

[0032] On the contrary, in the case where the card reader 2000 recognizes that the state information SI indicates an inactive state, the card reader 2000 may determine that the user device 1000 is in a power-off state, a power saving mode, a display-off state, or another state in which the user may not currently be able to observe the user device 1000. In this case, the card reader 2000 and the user device 1000 may perform an authentication process according to an exemplary embodiment of the inventive concept based on the shared service certificate SC.

[0033] The service authentication server 3000 stores a service certificate SC provided from the card reader 2000 or provided from a provider operating the card reader 2000. In the case of receiving a download request from a user of the user device 1000, the service authentication server 3000 may send the service certificate SC to the user device 1000. The service authentication server 3000 may communicate with the card reader 2000 and the user device 1000 through a wired or wireless network.

[0034] According to an exemplary embodiment of the above-described inventive concept, in the authentication system, the user device 1000 provides the state information SI to the card reader 2000. In the case where the state information SI provided from the user device 1000 indicates an inactive state, the card reader 2000 may perform the authentication process of the inventive concept based on the service certificate SC shared through the service authentication server 3000. Attacks or hacker attacks occurring in the inactive state may be prevented by the service certificate-based authentication process performed in the inactive state of the user device 1000.

[0035] Figure 2 It is shown Figure 1 A block diagram of a configuration of a user equipment. Figure 2 , the user device 1000 may include a host device 1100 , an NFC device 1200 , and an NFC antenna 1250 .

[0036] The host device 1100 may supply power to the NFC device 1200, and may communicate with the card reader 2000 through the NFC device 1200. In the active state, the host device 1100 may skip the NFC authentication process of the exemplary embodiment of the inventive concept, and may perform protocol communication with the card reader 2000. In the inactive state, communication between the host device 1100 and the card reader 2000 may be possible only after the authentication process with the card reader 2000 is completed through the NFC device 1200.

[0037] Here, the active state refers to a state in which the user operates (or manipulates) or uses the host device 1100, for example, within an expected (or alternatively, preset) time period. For example, the active state refers to a state in which the user conducts or has recently conducted a web search, or a state in which the user is or has recently been on a call. The inactive state refers to a state in which the display is turned off, which begins when the user does not manipulate the user device 1000 within an expected (or, alternatively, preset) time period or puts the user device 1000 aside during an expected (or, alternatively, preset) time period. Alternatively, the inactive state may refer to a state in which the user listens to music through an accessory such as headphones while the display is turned off. Alternatively, the inactive state may refer to a sleep mode of the user device 1000 or a power-off state in which the power is turned off. The inactive state may include all situations in which the user may not be observing the user device 1000.

[0038] In an example embodiment, the host device 1100 may include an application processor 1110, a power controller 1130, and a device interface 1150. The application processor 1110 executes various applications that drive the host device 1100. For example, the application processor 1110 executes software (e.g., an application program, an operating system, and a device driver) of the host device 1100. The application processor 1110 may be implemented with a homogeneous multi-core processor or a heterogeneous multi-core processor.

[0039] The power controller 1130 supplies and controls the power of the user device 1000. For example, the power controller 1130 may be a power management integrated circuit (PMIC). The power controller 1130 converts the power from the battery (not shown) by using a DC-DC converter or a voltage regulator so as to be suitable for the target device. Depending on the instructions of the application processor 1110, the power controller 1130 may reduce or block the power being supplied. For example, when the user is using the user device 1000, that is, in an active mode, the power controller 1130 may supply power to the application processor 1110 or the NFC device 1200. On the contrary, in an inactive mode where the user is not using the user device 1000, the power controller 1130 may reduce, minimize or block power to the display or unused components.

[0040] Depending on a request of the application processor 1110, the device interface 1150 may access the NFC device 1200. That is, the device interface 1150 provides an interface between the host device 1100 and the NFC device 1200. In order to communicate with a security block 1210 such as an embedded secure element (ESE) block of the NFC device 1200, the device interface 1150 may use a secure channel (e.g., a secure SPI (Serial Peripheral Interface)). Status information SI including information indicating whether a display of the host device 1100 is turned on or off may be sent to the NFC block 1230 of the NFC device 1200 through the device interface 1150. For example, the device interface 1150 may be a serial communication protocol such as I2C (Inter-Integrated Circuit), UART (Universal Asynchronous Receiver / Transmitter), and SPI.

[0041] The NFC device 1200 includes a security block 1210 (eg, an embedded secure element (ESE) block) and an NFC block 1230. The NFC device 1200 may communicate with a card reader 2000 through an NFC antenna 1250. Here, the security block 1210 and the NFC block 1230 may be implemented in the form of a single chip.

[0042] The security block 1210 stores the service certificate SC downloaded by the host device 1100 from the service authentication server 3000. The service certificate SC includes a service identifier (ID) (or provider ID) and public key information. The security block 1210 can perform an authentication process in an inactive state of the host device 1100. That is, the security block 1210 compares the service ID provided from the card reader 2000 with the service ID of the service certificate SC stored in the security block 1210. When the two service IDs match, the security block 1210 can perform one or more of the following operations for performing an authentication process with the card reader 2000: public key generation, random number generation, and encryption and decryption.

[0043] The NFC block 1230 provides an interface for performing NFC communication with the host device 1100 and the card reader 2000. The NFC block 1230 monitors whether communication with the card reader 2000 is possible, and when communication is possible, performs technical communication with the card reader 2000. Specifically, in the case where the NFC block 1230 receives information corresponding to an inactive state from the host device 1100, the NFC block 1230 transmits state information S1 indicating the inactive state of the user device 1000 to the card reader 2000. The state information S1 may be in the form of an RF command transmitted to the card reader 2000 through the NFC antenna 1250.

[0044] According to the above description, the user device 1000 includes the NFC device 1200 storing the service certificate SC downloaded from the service authentication server 3000. In the case where the host device 1100 is in an inactive state, the NFC device 1200 can perform an authentication operation with the card reader 2000 based on the service certificate SC. Therefore, the user device 1000 according to one or more exemplary embodiments of the inventive concept can provide high security against man-in-the-middle attacks to which the user device 1000 is vulnerable in an inactive state.

[0045] Figure 3 It is shown in detail Figure 2 Block diagram of the safety block. Figure 3, the security block 1210 includes a security interface 1211 (or ESE interface), a security processor 1213 (or ESE processor), an authentication storage 1215, and a key manager 1217. The security block 1210 can be formed in one chip together with the NFC block 1230. However, the manner of implementing the security block 1210 is not limited to the present disclosure. That is, it can be well understood that the security block 1210 can be implemented with a chip independent of the NFC block 1230.

[0046] The security interface 1211 provides an interface between the security block 1210 and the host device 1100 and between the security block 1210 and the NFC block 1230. The security interface 1211 can communicate with the application processor 1110 through the device interface 1150 of the host device 1100. The security block 1210 can be provided with a service certificate SC downloaded by the host device 1100 through the security interface 1211. The security interface 1211 can communicate with the device interface 1150 in the form of a serial peripheral device interface SPI with a security function. In addition, the security interface 1211 can communicate with the NFC block 1230 following a specific protocol (e.g., a single-wire protocol). The security interface 1211 can exchange random numbers, encrypted symmetric keys, etc. with the NFC interface 1231 in a security authentication process, which is initiated in an inactive state of the host device 1100.

[0047] The security processor 1213 processes various operations of the security block 1210. The security processor 1213 may perform an overall operation for receiving a service certificate SC from the host device 1100. In addition, the security processor 1213 may search the authentication storage 1215 for a service ID provided by the NFC block 1230, and may determine whether the found service ID and the provided service ID match. In addition, the security processor 1213 may request a symmetric key generation operation, a random number generation operation, and an encryption and decryption operation from the key manager 1217. In addition, considering the hardware characteristics of the security block 1210 or the NFC block 1230, the security processor 1213 may determine a time slot corresponding to a response time promised in a transaction with the card reader 2000. For example, considering the processing speed of the security block 1210, the security processor 1213 may determine a time slot T2 for responding to a request from the card reader 2000. In addition, the security processor 1213 may allow the key manager 1217 to encrypt the value of the time slot T2 by using a symmetric key, and may transmit the encrypted value to the card reader 2000. In addition, the security processor 1213 may decrypt the encrypted time slot T1 transmitted from the card reader 2000, and may transmit the decrypted time slot T1 to the NFC block 1230. The security processor 1213 may exchange and compare the encrypted random number with the card reader 2000 to determine whether the authentication is successfully performed. This will be described in detail with reference to the following drawings.

[0048] The authentication storage 1215 stores the service certificate SC downloaded from the service authentication server 3000. For example, the authentication storage 1215 can store the service ID, the public key used in the authentication process with the card reader 2000, etc. The authentication storage 1215 can be implemented with a non-volatile memory such as a one time programming (OTP) memory or a flash memory.

[0049] Depending on the request of the security processor 1213, the key manager 1217 may generate a symmetric key "K" for service authentication with the card reader 2000. The key manager 1217 may encrypt the symmetric key "K" by using the public key "P" stored in the authentication storage 1215. The encrypted symmetric key "K" may be sent to the card reader 2000, and the key manager 1217 may decrypt the encrypted random number by using the symmetric key "K" provided from the card reader 2000. In addition, the key manager 1217 may generate a random number, and may encrypt the random number by using the symmetric key "K". The key manager 1217 decrypts the encrypted random number provided from the card reader 2000. In addition, the key manager 1217 may encrypt the value of the time slot T2 to be sent to the card reader 2000 by using the symmetric key "K". In addition, the key manager 1217 may decrypt the value of the time slot T1 sent from the card reader 2000 by using the symmetric key "K".

[0050] The configuration and functions of the security block 1210 according to some example embodiments of the inventive concept are briefly described above. However, it is well understood that the configuration and functions of the security block 1210 of the example embodiments of the inventive concept can be modified or changed differently. For example, the functions of the hardware components that perform security operations can be implemented by using software executed by a processing circuit.

[0051] Figure 4 It is shown Figure 2 Block diagram of the configuration of the NFC block.

[0052] refer to Figure 4 , the NFC block 1230 may include an NFC interface 1231 , an NFC processor 1233 , a ROM 1235 , a power manager 1237 , and an RF modem 1239 .

[0053] The NFC interface 1231 provides an interface between the NFC block 1230 and the host device 1100 and between the NFC block 1230 and the security block 1210. The NFC interface 1231 can communicate with the application processor 1110 through the device interface 1150 of the host device 1100. The NFC block 1230 can receive on / off information of the display (or screen) of the host device 1100 or power-off information of the host device 1100 through the NFC interface 1231. The authentication process of the present invention is initiated in the off state or power-off state of the display. In this case, in order to perform authentication, the NFC interface 1231 can perform communication with the security interface 1211 of the security block 1210.

[0054] The NFC processor 1233 processes various operations of the NFC block 1230 associated with wireless communication. The NFC processor 1233 can execute the code stored in the ROM 1235 and can perform NFC technology communication or NFC protocol communication. In addition, the NFC processor 1233 can perform the authentication process of the inventive concept in the off state or power-off state of the display.

[0055] ROM 1235 stores a code for driving NFC block 1230. At the time of boot or reset of NFC device 1200, the code stored in ROM 1235 is sent to NFC processor 1233, and driving of NFC processor 1233 is possible. Authentication code AC for performing an authentication process in an inactive state of the present invention may be stored in ROM 1235. Authentication code AC includes a code for sending state information SI to card reader 2000 in an inactive state of host device 1100, and a code for operating and controlling NFC block 1230 on hardware in order to perform an authentication process based on state information SI. According to an exemplary embodiment of the present invention, authentication code AC may include a code capable of controlling whether RF communication is allowed depending on the result (success / failure) of performing the authentication process. In the off state of the display or in the power-off state, NFC processor 1233 may execute authentication code AC stored in ROM 1235.

[0056] The power manager 1237 may monitor the power state of the user device 1000 with reference to the power information “PWR Info.” provided from the power controller 1130 of the host device 1100. For example, when the power manager 1237 receives information indicating a power-off state from the power controller 1130, the power manager 1237 may send the power-off information to the NFC processor 1233. In this case, in order to activate the security authentication process of the exemplary embodiment of the inventive concept, the NFC processor 1233 may execute the authentication code AC. When the authentication code AC is executed, the overall function of the security block 1210 may be activated. In addition, in the technical communication with the card reader 2000, the NFC processor 1233 may send the state information SI corresponding to the inactive state.

[0057] The RF modem 1239 performs NFC with the card reader 2000 under the control of the NFC processor 1233. Before sending the transmission signal to the antenna 1250, the RF modem 1239 modulates the transmission signal to be sent to the card reader 2000. The RF modem 1239 can demodulate the reception signal received from the antenna 1250, and can send the demodulated signal to the NFC processor 1233 or any other target device. Specifically, in order to perform the authentication process using the time slot of the present invention, the RF modem 1239 may include an input / output timer 1232.

[0058] The input / output timer 1232 may count the transmission time and the reception time corresponding to the first time slot T1 provided from the card reader 2000. For example, the input / output timer 1232 may count whether the time from the time point when the RF modem 1239 transmits the request to the time point when the card reader 2000 responds to the request is within the first time slot T1. The time slot value may be determined in consideration of variables such as the length of the random number and the processing capability.

[0059] The configuration and operation of the NFC block 1230 are described above. However, it is well understood that the NFC block 1230 also includes components for additional performance, although in Figure 4 Not shown.

[0060] Figure 5 is a diagram illustrating a method of registering and downloading a service certificate according to one or more example embodiments of the inventive concept.

[0061] refer to Figure 5 , the card reader 2000 registers the service certificate SC on the service authentication server 3000. A user who wants to use the authentication process according to one or more example embodiments of the inventive concept may manipulate the user device 1000 so that the service certificate SC is downloaded from the service authentication server 3000.

[0062] In operation S10, the card reader 2000 may register a service certificate SC at the service authentication server 3000. The service certificate SC may be registered on the service authentication server 3000 by the card reader 2000 or a provider of the card reader 2000.

[0063] In operation S20, a user of the user device 1000 who wants to improve security performance in an inactive state may request downloading of a service certificate SC from the service authentication server 3000. The host device 1100 included in the user device 1000 may be manipulated by the user to request the service certificate SC from the service authentication server 3000 through a wired or wireless network.

[0064] In operation S30 , the service authentication server 3000 transmits a service certificate SC to the user equipment 1000 through a wired or wireless network in response to a request of the user equipment 1000 .

[0065] In operation S40 , the host device 1100 of the user device 1000 transmits the downloaded service certificate SC to the security block 1210 that performs a security function of the NFC device 1200 .

[0066] In operation S50 , the security block 1210 may store the downloaded service certificate SC in the authentication storage 1215 .

[0067] The method of registering and downloading a service certificate SC for performing an authentication process in an inactive state of the user device 1000 is described above. When the service certificate SC is stored in the security block 1210 of the user device 1000, the conditions for performing an authentication process in an inactive state according to an exemplary embodiment of the inventive concept are met.

[0068] Figure 6 is a diagram illustrating an authentication process between a card reader and a user device according to the present inventive concept.

[0069] refer to Figure 6 , when the user device 1000 is in an inactive state (eg, a display-off state), an authentication process according to an exemplary embodiment of the inventive concept is performed.

[0070] In operation S110, technical communication is performed (or, alternatively, negotiated) between the user device 1000 and the card reader 2000. The technical communication may refer to an operation in which each of the user device 1000 and the card reader 2000 detects an RF field and transmits an initial instruction of a ruled transmission speed. In the case where the user device 1000 and the card reader 2000 mutually recognize the RF field, the speed or wireless communication setting is transmitted synchronously with each other through the technical communication.

[0071] In operation S115, the user device 1000 sends the state information SI to the card reader 2000. The state information SI may be sent in operation S115 even while the technical communication initiated in operation S110 is being performed. For example, the state information SI may be information about whether the user device 1000 is in an active state or an inactive state. In the case where the user is using the user device 1000 or the display is turned on, the NFC block 1230 may send the state information SI indicating the active state to the card reader 2000. On the contrary, in the case where the display of the user device 1000 is turned off or the user device 1000 is in a power-off state, the NFC block 1230 may send the state information SI indicating the inactive state to the card reader 2000.

[0072] In operation S120, the card reader 2000 identifies the state information SI provided from the user device 1000, and determines whether to perform the authentication process according to the exemplary embodiment of the present invention, or whether to perform NFC protocol communication, depending on the identified state information SI. When it is determined that the state of the user device 1000 is an inactive state (yes), the process proceeds to operation S122 to perform the authentication process in the inactive state. On the contrary, when it is determined that the state of the user device 1000 is an active state (no), the process proceeds to operation S150 to perform NFC protocol communication in the active state.

[0073] In operation S122, the card reader 2000 starts the authentication process performed in the inactive state of the present inventive concept. That is, the card reader 2000 can send the service ID included in the service certificate SC registered at the service authentication server 3000 to the user device 1000. The service ID sent from the card reader 2000 is provided to the security block 1210 of the user device 1000.

[0074] In operation S124, the security block 1210 provided with the service ID may search the authentication storage 1215 in the security block 1210. In detail, the security processor 1213 of the security block 1210 may determine whether the service ID of the service certificate SC stored in the authentication storage 1215 matches the transmitted service ID. When the service ID stored in the authentication storage 1215 matches the service ID transmitted from the card reader 2000 (Yes), the process proceeds to operation S130 to perform the authentication process of the inventive concept. On the contrary, when the service ID matching the service ID transmitted from the card reader 2000 does not exist in the authentication storage 1215 (No), the authentication process according to the exemplary embodiment of the inventive concept performed in an inactive state may be terminated. In this case, the user device 1000 may not answer the card reader 2000.

[0075] In operation S130, the user device 1000 and the card reader 2000 perform an authentication process according to an exemplary embodiment of the present invention based on the mutually shared service certificate SC. That is, the authentication can be performed in a manner of generating and exchanging symmetric keys based on the public key included in the service certificate SC and generating and exchanging random numbers by using the exchanged symmetric keys. In addition, the user device 1000 and the card reader 2000 can exchange a time slot indicating a prescribed response time by using the symmetric key, and can monitor the time slot and the response time.

[0076] In operation S140, it is determined whether the authentication process performed in operation S130 is successful or failed. When the authentication process according to the exemplary embodiment of the inventive concept performed in the inactive state is successful (yes), the process proceeds to operation S150. When the authentication process according to the exemplary embodiment of the inventive concept performed in the inactive state fails (no), the authentication process may be terminated. In this case, the user device 1000 or the card reader 2000 may not answer.

[0077] In operation S150, protocol communication is performed between the user device 1000 and the card reader 2000. That is, the target block (eg, application processor) and the card reader 2000 may perform additional operations such as mutual data transfer or money payment through the NFC device 1200.

[0078] The above briefly describes the authentication process in an inactive state according to an exemplary embodiment of the inventive concept. Through the authentication process in an inactive state, the security performance of the user device 1000 such as a mobile device or an electronic device can be improved.

[0079] Figure 7 It is shown in detail Figure 6 Operation S130 of FIG. Figure 7 , an authentication operation based on the service certificate SC may be performed between the card reader 2000 and the security block 1210 included in the user device 1000. When the service ID transmitted by the card reader 2000 exists in the authentication storage 1215, the authentication process according to an exemplary embodiment of the inventive concept is initiated.

[0080] In operation S131, the security processor 1213 of the security block 1210 may request the key manager 1217 to generate a symmetric key “K.” The key manager 1217 generates the symmetric key “K” to be shared with the card reader 2000 by using a symmetric key generation algorithm.

[0081] In operation S132, the key manager 1217 of the security block 1210 encrypts the generated symmetric key "K" by using the public key "P" included in the service certificate SC. Therefore, the symmetric key "K" generated by the key manager 1217 is encrypted by using the public key "P".

[0082] In operation S133, the symmetric key P(K) encrypted by using the public key "P" is transmitted to the card reader 2000.

[0083] In operation S134, the card reader 2000 decrypts the encrypted symmetric key P(K). The card reader 2000 may decrypt the encrypted symmetric key "K" by using a private key existing in the card reader 2000. The decrypted symmetric key "K" may be stored in the authentication storage 1215 (refer to Figure 3 Thereafter, the card reader 2000 may transmit data encrypted by using the symmetric key “K” to the security block 1210 of the user device 1000, or may decrypt the encrypted ciphertext by using the symmetric key “K”.

[0084] In operation S135 and operation S136, the card reader 2000 and the user device 1000 exchange time slots T1 and T2 that specify the response time of the transaction. That is, the card reader 2000 and the user device 1000 encrypt and exchange the first time slot T1 and the second time slot T2 by using the symmetric key "K". The first time slot T1 corresponds to the response time that the card reader 2000 is to comply with with respect to the request of the user device 1000. In operation S135, the card reader 2000 transmits the first encrypted time slot K(T1) encrypted by using the symmetric key "K" to the security block 1210 of the user device 1000. The security block 1210 decrypts and stores the encrypted first time slot K(T1).

[0085] In operation S136, the security block 1210 encrypts the second time slot T2 by using the symmetric key "K". The security block 1210 sends the encrypted second time slot K(T2) to the card reader 2000. The card reader 2000 can decrypt the encrypted second time slot K(T2) by using the symmetric key "K", and can store the decrypted second time slot T2 in the authentication storage 1215.

[0086] In operation S137 , the card reader 2000 generates a first random number R1 and transmits the first random number R1 to the security block 1210 .

[0087] In operation S138, the security block 1210 encrypts the first random number R1 received from the card reader 2000 by using the symmetric key "K". The security block 1210 generates a second random number R2. The second random number R2 generated by the security block 1210 and the encrypted first random number K(R1) are transmitted to the card reader 2000 through the NFC block 1230. In this case, the time point of transmitting the second random number R2 and the encrypted first random number K(R1) may be within the second time slot T2 from the time point when the card reader 2000 receives the first random number R1. The input / output timer 1232 (reference timer) of the NFC block 1230 may be referred to. Figure 4 ) is used to manage the time point of sending the second random number R2 and the encrypted first random number K(R1) so as to send the second random number R2 and the encrypted first random number K(R1) within the second time slot T2.

[0088] In operation S139, the card reader 2000 receives the second random number R2 and the encrypted first random number K(R1). When the time point of receiving the second random number R2 and the encrypted first random number K(R1) is outside the second time slot T2, the authentication process can be terminated. However, when the time point of receiving the second random number R2 and the encrypted first random number K(R1) is within the second time slot T2, the card reader 2000 decrypts the encrypted first random number K(R1) by using the symmetric key "K". The card reader 2000 encrypts the received second random number R2 by using the symmetric key "K". In this case, it can be evaluated whether the decrypted first random number R1 matches the first random number R1 previously generated by the card reader 2000. When it is determined that the decrypted first random number R1 is different from the first random number R1 generated by the card reader 2000, the authentication process can be terminated. On the contrary, when it is determined that the decrypted first random number R1 matches the first random number R1 generated by the card reader 2000, the card reader 2000 sends the encrypted second random number K(R2) to the security block 1210 of the user device 1000. In this case, the encrypted second random number K(R2) may be sent within the first time slot T1.

[0089] In operation S140, the security block 1210 of the user equipment 1000 receives the encrypted second random number K(R2). When the time point of receiving the encrypted second random number K(R2) is outside the first time slot T1, the authentication process may be terminated. However, when the time point of receiving the encrypted second random number K(R2) is within the first time slot T1, the security block 1210 decrypts the encrypted second random number K(R2) by using the symmetric key "K".

[0090] It may be detected whether the decrypted second random number R2 matches the second random number R2 generated by the security block 1210. When it is determined that the decrypted second random number R2 matches the second random number R2 generated by the security block 1210 (yes), it is determined that the authentication in the inactive state is successful. In this case, the process proceeds to operation S142, and the security block 1210 of the user device 1000 may send an authentication success message to the card reader 2000. On the contrary, when it is determined that the decrypted second random number R2 does not match the second random number R2 generated by the security block 1210 (no), it is determined that the authentication in the inactive state fails. Therefore, the security block 1210 may not respond to the card reader 2000, and the authentication process may be terminated.

[0091] According to the above description, the card reader 2000 and the security block 1210 of the user device 1000 can share the symmetric key "K" by using the public key "P" in an inactive state. In addition, it is possible to exchange random numbers by using the symmetric key "K" to exchange time slots that specify mutual response times, and monitor to respond in accordance with the time slots. Through the above-mentioned security authentication, in the inactive state of the user device 1000, high security performance can be provided against various security attacks including man-in-the-middle attacks.

[0092] Figure 8 It is shown Figure 6 and Figure 7 The flowchart of the authentication operation of the card reader is shown in FIG. Figure 8 , the card reader 2000 may perform an authentication process according to an exemplary embodiment of the inventive concept depending on the state information SI of the user device 1000 .

[0093] In operation S210, the card reader 2000 may attempt to perform technical communication with the user device 1000. In order to periodically identify the user device 1000 that may communicate, the card reader 2000 detects the RF field and transmits the RF field for communication. When the user device 1000 that may communicate is identified, the card reader 2000 may send an initial instruction of a specified transmission speed. When the user device 1000 recognizes the initial instruction from the card reader 2000, data for initialization may be exchanged at a specified transmission speed. In this case, the user device 1000 may send state information SI indicating whether the user device 1000 is in an active state or an inactive state to the card reader 2000.

[0094] In operation S220, the card reader 2000 checks whether the state information SI is received from the user device 1000. When it is determined that the state information SI is received from the user device 1000 (Yes), the process proceeds to operation S230. On the contrary, when it is determined that the state information SI is not received from the user device 1000 (No), the process returns to operation S210.

[0095] In operation S230, the card reader 2000 checks the state information SI. When the state information SI received from the user device 1000 indicates an inactive state (Yes), the process proceeds to operation S240. On the contrary, when the state information SI received from the user device 1000 indicates an active state (No), the process proceeds to operation S270.

[0096] In operation S240, the card reader 2000 may transmit a service ID to the user device 1000. The service ID transmitted from the card reader 2000 is provided to the security block 1210 of the user device 1000. The security block 1210 determines whether the service ID transmitted from the card reader 2000 is identical to the service ID of the service certificate SC. When the same service ID exists in the security block 1210, the security block 1210 may transmit a symmetric key P(K) encrypted by using the public key "P" to the card reader 2000.

[0097] In operation S245, the card reader 2000 determines whether the symmetric key P(K) encrypted by using the public key "P" is received from the user device 1000. When it is determined that the symmetric key P(K) encrypted by using the public key "P" is not received from the user device 1000 (No), the card reader 2000 can terminate the authentication process. On the contrary, when it is determined that the symmetric key P(K) encrypted by using the public key "P" is received from the user device 1000 (Yes), the process proceeds to operation S250.

[0098] In operation S250, the card reader 2000 may perform an authentication process in an inactive state of the present invention based on the service certificate SC shared with the user device 1000. That is, the card reader 2000 decrypts the encrypted symmetric key P(K) and shares the symmetric key "K" with the security block 1210 of the user device 1000. The card reader 2000 sets time slots T1 and T2 based on the symmetric key "K" and exchanges encrypted random numbers R1 and R2 in accordance with the time slots T1 and T2. When it is determined that the exchanged random numbers R1 and R2 match the generated random numbers and the time slots T1 and T2 are observed, it can be determined that the authentication process of the present invention is successful.

[0099] In operation S260, the card reader 2000 checks whether an authentication success message is received from the user device 1000. When it is determined that the authentication success message is not received from the user device 1000 (No), the card reader 2000 may terminate the authentication process. On the contrary, when it is determined that the authentication success message is received from the user device 1000 (Yes), the process proceeds to operation S270.

[0100] In operation S270, the card reader 2000 performs protocol communication with the user device 1000. The card reader 2000 may perform additional subsequent operations such as mutual data transfer or monetary payment through a target block (eg, an application processor) and the NFC device 1200.

[0101] Fig. 9 is described in detail by Figure 8 Flow chart of operation S250 performed by the card reader. Fig. 9 , the card reader 2000 can share a symmetric key “K” with the user device 1000 , can encrypt / decrypt random numbers R1 and R2 based on the symmetric key “K”, and can set time slots T1 and T2.

[0102] In operation S251, the card reader 2000 receives a symmetric key P(K) encrypted by using a public key 'P' from the user device 1000.

[0103] In operation S252, the card reader 2000 decrypts the encrypted symmetric key P(K) by using the private key. The decrypted symmetric key “K” may be stored in the authentication storage 1215 included in the card reader 2000.

[0104] In operation S253, the card reader 2000 transmits the first time slot T1 to the user device 1000. In detail, the card reader 2000 encrypts the first time slot T1 by using the symmetric key "K" before transmitting the first time slot T1 to the user device 1000. The first time slot T1 is a value defining a response time of the card reader 2000 relative to a request of the user device 1000 in a random number exchange operation performed later.

[0105] In operation S254, the card reader 2000 receives the encrypted second time slot K(R2) from the user device 1000. The card reader 2000 may decrypt the encrypted second time slot K(R2) and may store the decrypted second time slot T2 in a designated storage area. The second time slot T2 is a value defining a response time of the user device 1000 relative to a request of the card reader 2000 in a random number exchange operation performed later.

[0106] In operation S255, the card reader 2000 generates a first random number R1 and sends the first random number R1 to the user device 1000. In order to generate the first random number R1, the card reader 2000 may drive a separate random number generator or a random number generation algorithm. The user device 1000 that receives the first random number R1 encrypts the received first random number R1 by using a symmetric key "K". The user device 1000 generates a second random number R2. The user device 1000 may send the generated second random number R2 and the encrypted first random number K(R1) to the card reader 2000.

[0107] In operation S256 , the card reader 2000 receives the second random number R2 and the encrypted first random number K( R1 ) transmitted from the user device 1000 .

[0108] In operation S257a and operation S257b, the card reader 2000 determines whether the second time slot T2 and the first random number R1 are satisfied. In operation S257a, the card reader 2000 determines whether the transmission time of the second random number R2 of the user device 1000 and the encrypted first random number K(R1) conforms to the second time slot T2. When the response of the user device 1000 conforms to the second time slot T2 (yes), the process proceeds to operation S257b. On the contrary, when the response of the user device 1000 does not conform to the second time slot T2 (no), the authentication process performed in the inactive state is terminated.

[0109] In operation S257b, the card reader 2000 decrypts the encrypted first random number K(R1) transmitted from the user device 1000 by using the symmetric key "K". The card reader 2000 checks whether the decrypted first random number R1 matches the first random number R1 generated for the first time. When the decrypted first random number R1 matches the first random number R1 generated for the first time (Yes), the process proceeds to operation S258. On the contrary, when the decrypted first random number R1 does not match the first random number R1 generated for the first time (No), the authentication process performed in the inactive state is terminated.

[0110] In operation S258, the card reader 2000 encrypts the second random number R2 received from the user device 1000 by using the symmetric key "K". The card reader 2000 sends the encrypted second random number K(R2) to the user device 1000. In this case, the card reader 2000 may send the encrypted second random number K(R2) within the first time slot T1 from the time point when the user device 1000 receives the second random number R2. The user device 1000 determines the success / failure of the authentication depending on the decrypted value of the encrypted second random number K(R2) and whether the first time slot T1 is observed. When the authentication is successful, the user device 1000 may send an authentication success message.

[0111] In operation S259, the card reader 2000 receives an authentication success message. In response to the authentication success message, the card reader 2000 may perform protocol communication with the user device 1000. When the authentication success message is not received, the card reader 2000 may determine that the inactive state authentication process has failed and may terminate the process.

[0112] Fig.10 It is shown Figure 6 and Figure 7 Flowchart of the authentication operation of the user device shown in FIG. Fig.10, the user equipment 1000 may perform the authentication process of the inventive concept depending on the state information SI.

[0113] In operation S310, the user device 1000 checks whether the card reader 2000 is connected (or linked). That is, the user device 1000 monitors whether technical communication with the card reader 2000 is possible. The user device 1000 detects the RF field emitted from the card reader 2000 and receives an initial instruction of a prescribed transmission speed sent from the card reader 2000.

[0114] In operation S320, the user device 1000 checks whether the transmission speed or the wireless communication setting is synchronized with each other through technical communication with the card reader 2000, that is, checks whether the user device 1000 and the card reader 2000 are linked. When it is determined that the user device 1000 and the card reader 2000 are linked (Yes), the process may proceed to operation S330. On the contrary, when it is determined that the user device 1000 and the card reader 2000 are not linked (No), the process may proceed to operation S310.

[0115] In operation S330, the user device 1000 sends the state information SI to the card reader 2000. The state information SI may be sent while the technical communication is being performed. For example, when the display of the user device 1000 is in the display-on state, the user device 1000 may send the state information SI corresponding to the active state to the card reader 2000. On the contrary, when the display of the user device 1000 is in the display-off state or the user device 1000 is in the power-off state, the user device 1000 may send the state information SI corresponding to the inactive state to the card reader 2000.

[0116] In operation S340, the user device 1000 performs an operation branch depending on the state information SI transmitted to the card reader 2000. When the current state is the active state (Active), the process proceeds to operation S390, in which a protocol communication with the card reader 2000 is performed. On the contrary, when the current state of the user device 1000 is the inactive state (Inactive), the process proceeds to operation S350.

[0117] In operation S350 , the user device 1000 receives a service ID from the card reader 2000 .

[0118] In operation S360, the user device 1000 searches for a service ID corresponding to the received service ID in the service certificate SC downloaded by the user device 1000. In detail, the user device 1000 may search for a service ID corresponding to the received service ID in the authentication storage 1215 included in the security block 1210.

[0119] In operation S370, the user device 1000 may determine whether the service ID of the service certificate SC stored in the authentication storage 1215 matches the received service ID. When the service ID stored in the authentication storage 1215 matches the service ID sent from the card reader 2000 (yes), the process proceeds to operation S380 to perform the authentication process of the present inventive concept. On the contrary, when the service ID matching the service ID sent from the card reader 2000 does not exist in the authentication storage 1215 (no), the authentication process of the present inventive concept performed in the inactive state may be terminated. In this case, the user device 1000 may not answer the card reader 2000.

[0120] In operation S380, the user device 1000 performs the authentication process of the inventive concept based on the service certificate SC shared with the card reader 2000. That is, the user device 1000 and the card reader 2000 may perform authentication in a manner of generating and exchanging a symmetric key "K" based on a public key "P" included in the service certificate SC, and generating and exchanging random numbers by using the exchanged symmetric key. In addition, the user device 1000 and the card reader 2000 may exchange a time slot by using the symmetric key, and may monitor the time slot and the response time.

[0121] In operation S390, protocol communication is performed between the user device 1000 and the card reader 2000. That is, the target block (eg, application processor) and the card reader 2000 may perform additional operations such as mutual data transfer or money payment through the NFC device 1200.

[0122] Fig.11 It is shown in detail Fig.10 Flow chart of operation S380. Fig.11 , the user device 1000 can share the symmetric key "K" with the card reader 2000, can encrypt / decrypt the random numbers R1 and R2 based on the symmetric key "K", and can set the time slots T1 and T2. When the service ID sent from the card reader 2000 is detected, the user device 1000 performs the following authentication process.

[0123] In operation S381, the user device 1000 generates a symmetric key 'K' to be shared with the card reader 2000 by using a symmetric key generation algorithm.

[0124] In operation S382, the user device 1000 encrypts the generated symmetric key "K" by using the public key "P" included in the service certificate SC. Therefore, the symmetric key "K" may be generated as a symmetric key P(K) encrypted by the public key "P".

[0125] In operation S383, the symmetric key P(K) encrypted by using the public key "P" is transmitted to the card reader 2000. In this case, the card reader 2000 encrypts the first time slot T1 by using the received symmetric key "K" before transmitting the first time slot T1 to the user device 1000.

[0126] In operation S384, the user equipment 1000 receives the first time slot K(T1) encrypted by using the symmetric key 'K.' The user equipment 1000 decrypts and stores the encrypted first time slot K(T1) by using the symmetric key 'K.'

[0127] In operation S385, the user device 1000 may encrypt the second time slot T2 by using the symmetric key "K" before sending the second time slot T2 to the card reader 2000. The second time slot T2 is a value that defines a response time of the user device 1000 relative to a request of the card reader 2000 in a random number exchange operation performed later. In this case, the card reader 2000 generates a first random number R1 and sends the first random number R1 to the user device 1000.

[0128] In operation S386 , the user device 1000 receives the first random number R1 transmitted from the card reader 2000 .

[0129] In operation S387, the user device 1000 encrypts the received first random number R1 by using the symmetric key "K". The user device 1000 generates a second random number R2. The user device 1000 may send the generated second random number R2 and the encrypted first random number K(R1) to the card reader 2000. The second random number R2 and the encrypted first random number K(R1) may be sent within a first time slot T1 from a time point when the card reader 2000 receives the first random number R1.

[0130] In operation S388 , the user device 1000 receives the encrypted second random number K( R2 ) transmitted from the card reader 2000 .

[0131] In operations S389a, S389b, and S389c, the user device 1000 determines whether the first time slot T1 and the second random number R2 are satisfied. In operation S389a, the user device 1000 determines whether the time from the time point when the card reader 2000 receives the second random number R2 to the time point when the encrypted second random number K(R2) is sent meets the first time slot T1. When the response of the card reader 2000 meets the first time slot T1 (Yes), the procedure proceeds to operation S389b. On the contrary, when the response of the card reader 2000 does not meet the first time slot T1 (No), the authentication process performed in the inactive state is terminated.

[0132] In operation S389b, the user device 1000 decrypts the encrypted second random number K(R2) transmitted from the card reader 2000 by using the symmetric key "K". It is checked whether the decrypted second random number R2 matches the second random number R2 generated by the user device 1000. When the decrypted second random number R2 matches the second random number R2 generated for the first time (yes), the procedure proceeds to operation S389c. On the contrary, when the decrypted second random number R2 does not match the second random number R2 generated for the first time (no), the authentication process performed in the inactive state is terminated.

[0133] In operation S389c, in order to inform the card reader 2000 that the authentication process performed in the inactive state is successful, the user device 1000 may send an authentication success message.

[0134] According to an exemplary embodiment of the inventive concept, even when the power of a user device using NFC communication is turned off or the display of the user device is turned off, a given security authentication operation can be performed. Therefore, the security performance of the user device can be improved.

[0135] The user device 1000 including the host device 1100 and the NFC device 1200 and the subcomponents of the user device 1000 including the application processor 1110, the power controller 1130, the security processor 1213 and the key manager 1217 of the security block 1210, and the NFC processor 1233 and the power manager 1237 of the NFC block 1230 may include a processing circuit, such as hardware including a logic circuit; a hardware / software combination, such as a processor that executes software; or a combination thereof. For example, the processing circuit may include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a programmable logic unit, a microprocessor, an application-specific integrated circuit (ASIC), etc. In addition, the authentication storage 1215 of the security block 1210 may include a volatile memory, and the read-only memory (ROM) 1235 of the NFC block 1230 may include a non-volatile memory.

[0136] The processing circuit may be a dedicated processing circuit, so that when the user device 1000 is in an inactive state, the user device 1000 may provide the card reader 2000 with state information (SI) indicating that the user device 1000 is in an inactive state, so as to instruct the card reader 2000 to perform the authentication process of the present invention based on the service certificate SC shared with the user device 1000 through the service authentication server 3000. Therefore, the dedicated processing circuit can improve the security of the NFC communication between the user device 1000 and the card reader 2000 by preventing attacks or hacker attacks that may occur when the user device 1000 is inactive.

[0137] While the inventive concepts have been described with reference to example embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications may be made to the inventive concepts without departing from the spirit and scope of the inventive concepts as set forth in the appended claims.

Claims

1. A method for operating a user device that performs near field communication (NFC) with a card reader, the method comprising: Store the service certificate downloaded from the service authentication server via the network; Sending status information to the card reader, the status information indicating whether the status of the user device is inactive; selectively receiving a service identifier ID from the card reader based on the status information; In response to the state of the user device being inactive and the service ID received from the card reader corresponding to a service certificate stored in the user device, performing an authentication process with the card reader based on a symmetric key; as well as In response to the authentication process being successful, an authentication success message is sent to the card reader. 2 . The method according to claim 1 , wherein the state information comprises information on whether the user equipment is in an inactive state or an active state.

3. The method according to claim 2, wherein the card reader is configured to: In response to the user device being inactive based on a display of the user device being turned off, sending the service ID to the user device, and In response to the user device being in an active state based on a display of the user device being turned on, performing protocol communications with the user device. 4 . The method according to claim 1 , wherein the service certificate further comprises a public key for encrypting or decrypting the service ID and the symmetric key.

5. The method of claim 4, wherein performing an authentication process with the card reader comprises: Generating the symmetric key by the user equipment; encrypting the symmetric key using the public key to generate an encrypted symmetric key; as well as The encrypted symmetric key is sent to the card reader.

6. The method according to claim 5, wherein performing an authentication process with the card reader further comprises: receiving a first encrypted time slot from the card reader, the first encrypted time slot comprising a first time slot encrypted using the symmetric key; as well as A second encrypted time slot is sent to the card reader, the second encrypted time slot comprising the second time slot encrypted using the symmetric key.

7. The method according to claim 6, wherein performing an authentication process with the card reader further comprises: receiving a first random number from the card reader; encrypting the first random number using the symmetric key to generate an encrypted first random number; Generating a second random number by the user equipment; as well as The second random number and the encrypted first random number are sent to the card reader.

8. The method according to claim 7, wherein: Sending the second random number and the encrypted first random number to the card reader includes: The second random number and the encrypted first random number are sent to the card reader so that the time from the time point of receiving the first random number to the time point of sending the second random number and the encrypted first random number is within a second time slot.

9. The method according to claim 7, wherein performing an authentication process with the card reader further comprises: receiving an encrypted second random number from the card reader, the encrypted second random number comprising a second random number encrypted using the symmetric key; decrypting the encrypted second random number using the symmetric key to extract a decrypted second random number; as well as A determination is made as to whether the decrypted second random number corresponds to a second random number previously generated by the user device.

10. The method according to claim 9, wherein: In response to the decrypted second random number extracted from the encrypted second random number received from the card reader corresponding to a second random number previously generated by the user device, the user device determines that the authentication process is successful.

11. A user equipment, comprising: a host device configured to generate status information indicating an active state or an inactive state; as well as NFC device, configured as Storage service certificates, and Based on the state information, NFC communication with the card reader is performed in the following manner, sending the status information to the card reader, wherein the status information indicates whether the status of the user device is inactive, selectively receiving a service identifier (ID) from the card reader based on the status information, and In response to the state of the user device being inactive and the service ID received from the card reader corresponding to a service certificate stored in the NFC device, an authentication process with the card reader is performed.

12. The user device according to claim 11, wherein the NFC device comprises: The processing circuit is configured to: executing the functions of a security block, the security block being configured to store the service certificate and perform an authentication process based on the service certificate; as well as The NFC block performs the functions of sending the status information to the card reader using NFC communication and providing an interface between the host device and the card reader and an interface between the security block and the card reader.

13. The user equipment according to claim 12, further comprising: a memory associated with the security block, the memory configured to store the service credential; as well as a security interface configured to provide an interface between the host device or the NFC block and the security block, and wherein when performing the functions of the security block, the processing circuit is configured to, a key manager configured to generate a symmetric key to be shared with the card reader, perform an encryption or decryption operation using a public key of the service certificate and the symmetric key to generate a random number, and decrypt the encrypted random number based on the symmetric key to generate a decrypted random number; as well as The security processor is configured to determine whether the service ID sent from the card reader exists in the service certificate and control the key manager to perform an authentication process with the card reader.

14. The user equipment according to claim 13, further comprising: an NFC interface configured to provide an interface with the host device or the security block; a read-only memory ROM configured to store an authentication code for performing an authentication process; a wireless modem configured to perform near field wireless communication with the card reader; and wherein when performing the functions of the NFC block, the processing circuit is configured to, executing the authentication code to provide the status information to the card reader via the wireless modem, and The security block and the wireless modem are controlled to perform an authentication process.

15. The user equipment according to claim 14, wherein when executing the function of the NFC block, the processing circuit is configured to: The response time of transactions communicated with the card reader is counted.

16. The user equipment according to claim 15, wherein when executing the function of the NFC block, the processing circuit is configured to: monitoring whether the card reader complies with a first time slot provided from the card reader based on the response time, and When the response of the card reader does not conform to the first time slot, it is determined that the authentication process has failed.

17. The user equipment according to claim 16, wherein when executing the function of the NFC block, the processing circuit is configured to: determining whether the decrypted random number corresponds to a random number previously generated by the user device, and When the decrypted random number does not correspond to the random number previously generated by the user equipment, it is determined that the authentication process has failed.

18. An authentication system comprising: A card reader configured to register a service certificate at a service authentication server; as well as A user device is configured to: storing the service certificate downloaded from the service authentication server via a network, In a state where NFC communication with the card reader can be performed, status information is sent to the card reader, wherein the status information indicates whether the status of the user device is inactive, selectively receiving a service identifier ID from the card reader based on the status information; as well as In response to the state of the user device being inactive and the service ID received from the card reader corresponding to a service certificate stored in the user device, an authentication process with the card reader is performed based on a symmetric key.

19. The authentication system according to claim 18, wherein the card reader is configured to send a service ID corresponding to the service certificate to the user device with reference to the state information.

20. The authentication system according to claim 18, wherein: When the service ID received from the card reader corresponds to the service ID in the service certificate, the user device is configured to: sending a symmetric key to the card reader using the public key included in the service certificate, and When exchanging random numbers with the card reader, an authentication process with the card reader is performed using a time slot for setting a response time.

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