Contactless secure element, device and extended ATQB transmission control method

Abstract

To enable a non-contact type secure element to control the transmission of an extended ATQB according to the necessity of the non-contact type secure element in the case that a request command permits the transmission of the extended ATQB.SOLUTION: Request command processing means 10 of a non-contact type secure element 1 inspects the value of an extension parameter to be included in an extended ATQB in the case that a request command received from a terminal 3 permits the transmission of the extended ATQB, transmits a non-extended ATQB that does not include an extension byte obtained by coding the extension parameter in the case that the extension parameter is a default value, and transmits an extended ATQB including the extension byte in the case that the extension parameter is not the default value.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a secure element, which is a semiconductor product having robust tamper resistance against external analysis attacks. [Background technology]

[0002] Secure elements, which are semiconductor products with strong tamper resistance against external analysis attacks, are installed in various devices. The main use of devices equipped with secure elements is for financial settlement.

[0003] Conventionally, contact-based financial payments have been the mainstream, where financial payments are made through contact communication. The secure element used in contact-based financial payments is a contact-type secure element with a contact interface. A well-known device equipped with a contact-type secure element is the contact-type IC card.

[0004] In recent years, contactless financial payments, which are made through contactless communication and are considered to be more convenient for consumers, have become widespread. The secure element used in contactless financial payments is a contactless secure element with a contactless interface. Well-known devices equipped with contact-type secure elements include contactless IC cards and smart devices. A smart device is a multi-function terminal that can be used for a variety of purposes. Well-known examples of smart devices include smartphones and smartwatches.

[0005] Many contactless secure elements perform proximity wireless communication compliant with the ISO14443 standard (Non-Patent Document 1). The ISO14443 standard specifies two types, Type A and Type B, but the present invention only targets Type B. Note that Type A and Type B differ in their modulation method and encoding (contents of Part 2) and initialization process (contents of Part 3).

[0006] Part 3 of the ISO14443 standard prescribes the commands used for initialization and the responses to these commands. The commands used for initialization include a request command to search for a contactless secure element that complies with Type B, and the ATTRIB command (PICC selection command, Type B), which is a command to select one contactless secure element.

[0007] In Part 3 of the ISO14443 standard, there are two types of Type B request commands: REQB (REQB: REQuest command, type B) and WUPB (WUPB: Wake-UP command, Type B), but we do not distinguish between these commands here. In Part 3 of the ISO14443 standard, the response to a Type B request command is called ATQB (ATQB: Answer To reQuest, Type B).

[0008] When a contactless secure element performs proximity wireless communication with a terminal, it is necessary to present the communication parameters used by the contactless secure element to the terminal. In Type B of the ISO14443 standard, these communication parameters are included in ATQB.

[0009] Among the communication parameters included in ATQB is a communication parameter called TR2. TR2 is a 4-bit data, and is a communication parameter that specifies the minimum time required for a contactless secure element from the end of its response until it is able to receive the next frame. The specific value of TR2 is specified in Part 3 of the ISO14443 standard.

[0010] Since the contactless secure element selected by the ATTRIB command transitions to a higher layer, in Part 3 of the ISO14443 standard, a frame guard time required by the contactless secure element from sending the ATTRIB response until it is able to receive the next frame can be provided instead of TR2. In Part 3 of the ISO14443 standard, an ATQB to which an extension byte in which communication parameters related to the frame guard time are coded is added is called an extended ATQB (Fig. 9 of Patent Document 1).

[0011] In Part 3 of the ISO14443 standard, the condition under which a contactless secure element can transmit an extended ATQB is limited to cases where the REQB command indicates that the terminal supports the extended ATQB. If the request command transmitted by the terminal does not indicate that the terminal supports the extended ATQB, the contactless secure element must transmit a non-extended ATQB, which is an ATQB that does not add an extension byte, without transmitting an extended ATQB.

[0012] On the other hand, if the request command indicates that the terminal supports the extended ATQB, the contactless secure element is permitted to transmit the extended ATQB, but the contactless secure element does not necessarily have to transmit the extended ATQB even if the transmission of the extended ATQB is permitted. Even if the transmission of the extended ATQB is permitted, the contactless secure element can transmit the non-extended ATQB.

[0013] In other words, in Part 3 of the ISO14443 standard, even if a request command indicates that a terminal supports the extended ATQB, the decision as to whether or not to transmit the extended ATQB is left to the contactless secure element side. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] JP 2010-238080 A [Non-patent literature]

[0015] [Non-Patent Document 1] ISO / IEC 14443-3:2016 Initialization and anticollision Summary of the Invention [Problem to be solved by the invention]

[0016] Therefore, an object of the present invention is to enable a contactless secure element to control the transmission of an extended ATQB according to necessity when the transmission of an extended ATQB is permitted by a request command. [Means for solving the problem]

[0017] The first invention for solving the above-mentioned problems is a contactless secure element characterized by having a request command processing means which, when a request command received from a terminal allows transmission of an extended ATQB, checks the value of an extended parameter to be included in the extended ATQB, and if the extended parameter is a default value, transmits a non-extended ATQB that does not include an extended byte coded with the extended parameter, and if the extended parameter is not a default value, transmits an extended ATQB that includes the extended byte.

[0018] Furthermore, a second invention is a device that implements the contactless secure element described in the first invention.

[0019] Furthermore, the third invention is a method for controlling the transmission of an extended ATQB, characterized in that it includes a step of checking the value of an extended parameter to be included in the extended ATQB when the contactless secure element is permitted to transmit an extended ATQB by a request command received from a terminal, and a step of the contactless secure element transmitting a non-extended ATQB that does not include an extended byte coded with the extended parameter if the extended parameter is a default value, and transmitting an extended ATQB that includes the extended byte if the extended parameter is not the default value. Effect of the Invention

[0020] In order to solve the problems related to the present invention, the present invention is configured to control the transmission of an extended ATQB in accordance with the value of an extended parameter stored in the contactless secure element when the transmission of an extended ATQB is permitted by a request command. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a diagram illustrating an example of a device equipped with a contactless secure element. [Diagram 2] FIG. 1 is a block diagram of a contactless secure element. [Diagram 3] FIG. 4 is a diagram for explaining the format of a request command. [Figure 4] FIG. 13 is a diagram for explaining the format of ATQB, which is a response to a request command. [Diagram 5] 4A and 4B are diagrams for explaining the operation of a contactless secure element when a request command is received. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described. This embodiment is for the purpose of facilitating understanding of the present invention, and the present invention is not limited to this embodiment. Furthermore, unless otherwise specified, the drawings are schematic diagrams drawn for the purpose of facilitating understanding of the present invention.

[0023] Fig. 1 is a diagram for explaining an example of a device 2 equipped with a contactless secure element 1. In Fig. 1, the device 2 equipped with the contactless secure element 1 is illustrated as a contactless IC card that communicates with a terminal in a contactless manner by short-range wireless communication. In Fig. 1, the device 2 is shaped like a credit card.

[0024] The terminal 3 that performs short-range wireless communication with the device 2 is equipped with a terminal antenna not shown, and the device 2 that performs short-range wireless communication with the terminal 3 is equipped with a device antenna 21 for electromagnetic coupling with the terminal antenna equipped on the terminal 3.

[0025] 1 has a three-layer structure formed by laminating a surface sheet 22, an inlay sheet 20, and a back sheet 23. The contactless secure element 1 and the device antenna 21 are mounted on the inlay sheet 20, and the contactless secure element 1 is connected to both ends of the device antenna 21 provided in the device 2.

[0026] The terminal 3 generates an electromagnetic field by using a terminal antenna which serves as a primary coil. The device antenna 21 provided in the device 2 serves as a secondary coil, and an induced electromotive force is generated in the device antenna 21 which exists in the electromagnetic field. The contactless secure element 1 connected to both ends of the device antenna 21 operates by using the induced electromotive force generated in the device antenna 21. In addition, the terminal 3 and the contactless secure element 1 transmit and receive data by using the electromagnetic field generated by the terminal 3.

[0027] 2 is a block diagram of the contactless secure element 1. The contactless secure element 1 according to this embodiment includes, as circuits, a contactless interface 101 (RF: Radio Frequency), a CPU 100 (CPU: Central Processing Unit), a RAM 102 (RAM: Random Access Memory), a ROM 103 (ROM: Read Only Memory), an NVM 104 (NVM: Non-Volatile Memory), a random number generator 105 (RNG: Random Number Generator), a CRC calculation circuit 106 (CRC: Cyclic Redundancy Check), and a power supply circuit 107. Naturally, the circuits integrated in the contactless secure element 1 are not limited to these circuits.

[0028] The power supply circuit 107 is connected to the device antenna 21. The power supply circuit 107 rectifies the induced electromotive force generated in the device antenna 21, and serves as a circuit for generating an operating voltage for the contactless secure element 1.

[0029] The contactless interface 101 is a circuit that performs contactless communication with the terminal 3, and is connected to the device antenna 21. The contactless interface 101 receives data transmitted by the terminal 3 by demodulating data contained in the AC signal received by the device antenna 21. The contactless interface 101 also transmits data to the terminal 3 by modulating the AC signal received by the device antenna 21 based on data to be transmitted to the terminal 3.

[0030] RAM 102, ROM 103 and NVM 104 are memories provided in the contactless secure element 1. RAM 102 is an electrically rewritable volatile memory. ROM 103 is a read-only nonvolatile memory. NVM 104 is an electrically rewritable nonvolatile memory. For example, NVM 104 is an EEPROM (Electrically Erasable Programmable Read-Only Memory). It is common to use ROM 103 to store the program code of an operating system, and NVM 104 to store the data of the operating system and the program code of applications.

[0031] The random number generator 105 is a circuit that generates random numbers. The CRC calculation circuit 106 is a circuit that calculates a 2-byte CRC based on the data input to the CRC calculation circuit 106.

[0032] The CPU 100 of the contactless secure element 1 interprets the program code stored in the memory and executes a predetermined process. The process executed by the CPU 100 of the contactless secure element 1 includes a process of executing a command received from the terminal 3 using the contactless interface 101.

[0033] This embodiment is characterized by a transmission control method of an extended ATQB according to Part 3 of the ISO 14443 standard. The subject that executes the processing of the request command is the CPU 100 of the contactless secure element 1. When the CPU 100 of the contactless secure element 1 executes the processing of the request command, the CPU 100 of the contactless secure element 1 functions as the request command processing means 10 according to the present invention.

[0034] 3 is a diagram for explaining the format of a request command. Note that a 2-byte CRC is added to the end of the request command, but the CRC is omitted in FIG.

[0035] The request command contains three bytes. The first byte of the request command is data called APf (APf: Anticollision Prefix f, used in REQB / WUPB, Type B). APf is a fixed value, and its value is '05' ('x' means hexadecimal notation). The second byte of the request command is data called AFI (Application Family Indicator). AFI is data used by the terminal 3 to select a contactless secure element 1. Only the contactless secure element 1 that corresponds to the AFI responds to the request command. Note that if AFI is '00', all contactless secure elements 1 respond to the request command.

[0036] The third byte of the request command is data called PARAM. PARAM is a byte that indicates parameters, and contains three parameters. b5 of PARAM is data indicating whether terminal 3 supports extended ATQB or not. When b5 of PARAM is (0)b (()b means binary notation), it means that terminal 3 does not support extended ATQB. When b5 of PARAM is (1)b, it means that terminal 3 supports extended ATQB. b4 of PARAM is data indicating the type of request command. When b4 of PARAM is (0)b, it means that the request command is a REQB command. When b4 of PARAM is (1)b, it means that the request command is a WUPB command. Note that b1-b3 of PARAM are data indicating the number of slots to be used in anti-collision related processing.

[0037] Figure 4 is a diagram explaining the format of the ATQB, which is the response to a request command. As with the request command, a 2-byte CRC is added to the end of the ATQB, but the CRC is omitted in Figure 4. The ATQB format does not change whether it is a REQB command or a WUPB command. A non-extended ATQB, which is not an extended ATQB, is 12 bytes of data. In the case of an extended ATQB, one extension byte is added to the end of the non-extended ATQB. Therefore, the extended ATQB becomes 13 bytes of data.

[0038] The first byte of ATQB is a fixed value, and its value is '50'. '50' is the data indicating that it is an ATQB. The second to fifth bytes of ATQB are data called PUPI (PUPI: Pseudo-Unique PICC Identifier). PUPI is the data used by the terminal 3 to select the device 2 equipped with the contactless secure element 1 in anti-collision.

[0039] The sixth to ninth bytes of ATQB are application data. The application data of ATQB is data for notifying the terminal 3 of the application installed in the contactless secure element 1.

[0040] In the case of a non-extended ATQB, the data in bytes 10 to 12 of the ATQB is protocol information, and in the case of an extended ATQB, the data in bytes 10 to 13 of the ATQB is protocol information. Bytes 1 to 3 of the protocol information are common to both non-extended and extended ATQBs. The fourth byte of the protocol information in an extended ATQB is the extension byte added to the extended ATQB.

[0041] The first to third bytes of the protocol information include the allowable transmission speed, maximum frame size, protocol type, FWI (Frame Waiting time Integer), ADC (Application Data Coding), and FO (Frame Options). The allowable transmission speed indicates the transmission speed supported by the contactless secure element 1. The maximum frame size indicates the maximum frame size supported by the contactless secure element 1. The protocol type indicates the minimum value of TR2 and the protocol supported by the contactless secure element 1 (for example, the transmission protocol specified in Part 4 of the ISO14443 standard). FWI is an integer value used to calculate the frame waiting time. ADC indicates the coding of application data supported by the contactless secure element 1. FO indicates the support status of the node address and card identification information.

[0042] The fourth byte in the protocol information of the extended ATQB contains the extended parameter SFGI (Start-up Frame Guard Time Integer). SFGI is 4-bit data and is an integer value used to calculate the frame guard time required by the contactless secure element 1 from sending the ATTRIB response until it can receive the next frame. Part 3 of the ISO14443 standard specifies the default value of SFGI. The value is (0000)b.

[0043] If the default value of SFGI is included in the extended ATQB, the frame guard time required by the contactless secure element 1 after sending the ATTRIB response until it can receive the next frame will not be longer than with a non-extended ATQB, and there will be no point in sending the extended ATQB.

[0044] Therefore, when the contactless secure element 1 according to this embodiment is indicated by a request command transmitted from the terminal 3 to support the extended ATQB, it controls the transmission of the extended ATQB based on the value of SFGI preset in the contactless secure element 1. When the SFGI preset in the contactless secure element 1 is a default value, the contactless secure element 1 transmits a non-extended ATQB. When the SFGI preset in the contactless secure element 1 is other than the default value, the contactless secure element 1 transmits an extended ATQB. The default value of SFGI is stored in the NVM 104 or ROM 103 of the contactless secure element 1.

[0045] Fig. 5 is a diagram explaining the operation of the contactless secure element 1 when a request command is received. At the beginning of the procedure illustrated in Fig. 5, the contactless secure element 1 receives the request command transmitted by the terminal 3 (step S1). The contactless secure element 1 that can receive the request command transmitted by the terminal 3 is the contactless secure element 1 that exists in the electromagnetic field generated by the terminal 3. When the contactless secure element 1 receives the request command transmitted by the terminal 3, the request command processing means 10 is activated.

[0046] The request command processing means 10 of the contactless secure element 1 judges whether the terminal 3 that transmitted the request command supports extended ATQB (step S2). Whether the terminal 3 that transmitted the request command supports extended ATQB is indicated by b5 of PARAM, which is the third byte data of the request command. If b5 of PARAM is (0)b, the request command processing means 10 of the contactless secure element 1 judges that the terminal 3 that transmitted the request command does not support extended ATQB. If b5 of PARAM is (1)b, the request command processing means 10 of the contactless secure element 1 judges that the terminal 3 that transmitted the request command supports extended ATQB.

[0047] If it is determined that the terminal 3 that sent the request command does not support the extended ATQB, the request command processing means 10 of the contactless secure element 1 assembles a non-extended ATQB in RAM 102, for example by generating a PUPI using a random number generator (step S3), and then transmits the non-extended ATQB using the contactless interface 101 (step S4), and the procedure in Figure 5 is terminated.

[0048] If it is determined that the terminal 3 that transmitted the request command supports extended ATQB, the request command processing means 10 of the contactless type secure element 1 checks whether the SFGI stored in the contactless type secure element 1 is the default value (step S5). In Part 3 of the ISO14443 standard, the default value of SFGI is (0000)b. If the SFGI stored in the contactless type secure element 1 is (0000)b, the request command processing means 10 of the contactless type secure element 1 determines that the SFGI stored in the contactless type secure element 1 is the default value. If the SFGI stored in the contactless type secure element 1 is not (0000)b, the request command processing means 10 of the contactless type secure element 1 determines that the SFGI stored in the contactless type secure element 1 is not the default value.

[0049] If the SFGI stored in the contactless secure element 1 is the default value, the process proceeds to step S3 in Fig. 5, the request command processing means 10 transmits a non-extended ATQB, and the procedure in Fig. 5 ends. If the SFGI stored in the contactless secure element 1 is not the default value, the request command processing means 10 assembles an extended ATQB in which the SFGI stored in the contactless secure element 1 is included in the 13th byte in the RAM 102 (step S6), and then transmits the extended ATQB using the contactless interface 101 (step S7), and the procedure in Fig. 5 ends.

[0050] As described above, when transmission of an extended ATQB is permitted by a request command, the contactless secure element 1 according to this embodiment is configured to control the transmission of the extended ATQB according to the value of the extended parameter stored in the contactless secure element 1. Specifically, the contactless secure element 1 according to this embodiment transmits the extended ATQB only when the extended parameter SFGI is not the default value, that is, only when the frame guard time calculated from the SFGI is longer than that of the non-extended ATQB. [Explanation of symbols]

[0051] 1 Contactless Secure Element 10. Request command processing means

Claims

1. A contactless secure element characterized by comprising a request command processing means for, when transmission of an extended ATQB is permitted by a request command received from a terminal, checking the value of an extended parameter to be included in the extended ATQB, and if the extended parameter is a default value, transmitting a non-extended ATQB that does not include an extended byte coded with the extended parameter, and if the extended parameter is not a default value, transmitting an extended ATQB that includes the extended byte.

2. A device incorporating the contactless secure element according to claim 1.

3. A method for controlling the transmission of an extended ATQB, comprising the steps of: when a contactless secure element is permitted to transmit an extended ATQB by a request command received from a terminal, checking the value of an extended parameter to be included in the extended ATQB; when the extended parameter is a default value, the contactless secure element transmits a non-extended ATQB that does not include an extended byte coded with the extended parameter; and when the extended parameter is not a default value, the contactless secure element transmits an extended ATQB that includes the extended byte.

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