JP2014071522A - Ic card, ic card processing program, and communication method - Google Patents

Abstract

An IC card and an IC card capable of taking a means for quickly returning to a normal communication state even when a communication error occurs when transitioning from a low-speed communication state to a high-speed communication state A processing program and a communication method are provided.
When a high speed communication request is received from a reading device 2 when low speed communication is set, the IC card 1 transmits a high speed communication response to the reading device 2 and changes the setting from low speed communication to high speed communication. Thereafter, when the command received from the reading device 2 cannot be interpreted, the process is stopped without transmitting a retransmission request for the command to the reading device 2.
[Selection] Figure 3

Description

  The present invention relates to a technical field of an IC card that can be set by selecting either low-speed communication or high-speed communication with an external device.

  Due to advances in cryptanalysis technology, IT systems are being required to have a high security level. In order to realize a strong IT system, the length of the encryption key that controls the security is gradually expanded, and the amount of communication data is steadily expanding accordingly. In order to transmit and receive large amounts of data without stress, it is necessary to increase the communication speed and exchange large amounts of data instantaneously. High-speed communication cannot be realized unless both connected devices have a function capable of high-speed communication, and even if only one of them has. Therefore, in order to achieve high security in an IT system in which a large number of unspecified devices are connected to each other, and to ensure that any device can communicate without any problem, any device is the other party when starting each device. Even if it exists, it is set to a communication speed that can be operated, and a communication protocol that starts high-speed communication after recognizing that devices having a high-speed communication function are connected is required.

  For example, the IC card disclosed in Patent Document 1 includes a low-speed interface that communicates with a low-speed communication protocol and a high-speed interface that communicates with a high-speed communication protocol, and when a reset signal is received from an external device through the low-speed interface. In response to the reset signal, initial response information (ATR (Answer To Reset)) including high-speed communication protocol information is transmitted to an external device by low-speed communication. As a result, when the IC card receives a request to change the setting from the external device to the high-speed communication according to the high-speed communication protocol information, the IC card changes the setting from the low-speed communication to the high-speed communication. High-speed communication with equipment.

  By the way, an electrical signal transmitted by high-speed communication is very susceptible to noise. Noise can be classified into internal noise generated by the characteristics of circuit elements and cables, and external noise generated by the influence of electromagnetic waves, etc., but in the communication mode with a short signal interval by high-speed communication, any noise is a signal. It may cause the reading error. In general communication rules, there are rules that define the handling of error correction, retransmission request, and the like that should be performed when an abnormal signal is received. This is an effective means for quickly resolving an error and returning to a normal communication state for a signal error that is likely to occur during high-speed communication.

Special table 2009-527044 gazette

  However, errors that occur during high-speed communication can be resolved relatively easily, but the behavior for errors that occur during switching from the low-speed communication state to the high-speed communication state is interpreted differently by the devices that are communicating. In some cases, the error cannot be resolved and the normal communication state cannot be restored.

  Therefore, the present invention has been made in view of the above points and the like, and even when a communication error occurs when transitioning from the low-speed communication state to the high-speed communication state, the normal communication state is quickly restored. An object of the present invention is to provide an IC card, a processing program for the IC card, and a communication method capable of taking measures for the purpose.

  In order to solve the above problems, the invention according to claim 1 is an IC card that can be set by selecting either low speed communication or high speed communication with an external device, and the low speed communication is set. When a request for changing the setting from the external device to high-speed communication is received from the external device, a message indicating acceptance of the setting change is transmitted to the external device, and the setting is changed from the low-speed communication to the high-speed communication. A changing means and a process stopping means for stopping the process without transmitting a request for retransmission of the command to the external device when the command received from the external device cannot be interpreted after the message is transmitted to the external device. And.

  According to a second aspect of the present invention, in the IC card according to the first aspect, the command transmitted from the external device after the telegram is transmitted to the external device is a command transmitted by low-speed communication. It is characterized by that.

  According to a third aspect of the present invention, there is provided a computer included in an IC card that can be set by selecting either low speed communication or high speed communication with an external device when the low speed communication is set. When receiving a setting change request from an external device to high-speed communication, transmitting a message indicating acceptance of the setting change to the external device and changing the setting from low-speed communication to high-speed communication; and When the command received from the external device cannot be interpreted after being transmitted to the external device, the step of stopping the processing without transmitting a retransmission request for the command to the external device is executed. .

  The invention according to claim 4 is a communication method performed by an IC card that can be set by selecting either low-speed communication or high-speed communication with an external device, wherein the low-speed communication is set. When receiving a setting change request from the external device to high-speed communication, transmitting a message indicating acceptance of the setting change to the external device, and changing the setting from the low-speed communication to the high-speed communication, And a step of stopping the process without transmitting a request for retransmission of the command to the external device when the command received from the external device cannot be interpreted after the message is transmitted to the external device. And

  According to the present invention, even when a communication error occurs when transitioning from a low-speed communication state to a high-speed communication state, a means for quickly returning to a normal communication state can be taken.

It is a block diagram which shows the example of a schematic structure of the IC chip mounted in an IC card. It is a figure which shows an example of the conventional behavior when a communication error generate | occur | produces when changing from a low-speed communication state to a high-speed communication state. It is a flowchart which shows an example of a process of CPU11 in the IC card 1 which concerns on this embodiment.

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

  First, with reference to FIG. 1, the configuration and functions of an IC chip (for example, a one-chip microcomputer) mounted on an IC card will be described. FIG. 1 is a block diagram illustrating a schematic configuration example of an IC chip mounted on an IC card. The IC card 1 can be set by selecting either low-speed communication or high-speed communication with the reading device (reader / writer) 2. The IC card 1 can be applied as an IC card mounted on a portable terminal such as a mobile phone or a smart phone, in addition to an IC card used in various fields such as finance, communication, and traffic. The reading device 2 is an example of an external device that is a device opposite to the IC card 1.

  As shown in FIG. 1, an IC chip C includes a CPU (Central Processing Unit) 11 that performs signal processing, a ROM (Read Only Memory) 12, a nonvolatile memory (for example, a flash memory or an EEPROM) 13, and a RAM that temporarily stores data. (Random Access Memory) 14 and an I / O port (input / output port) 15 are provided. As shown in FIG. 1, the I / O port 15 has eight terminals C1 to C8 defined by ISO / IEC7816 or the like. Here, the C1 terminal is a power supply terminal (VCC), and the C5 terminal is a ground terminal (GND). The C2 terminal is a reset terminal (RST) and is used for inputting a reset signal from the reading device 2. The C3 terminal is a clock terminal (CLK) used for inputting a clock signal. The C7 terminal is a terminal that serves as an interface with the reading device 2 and is used for communication with the reading device 2.

  The ROM 12 or the non-volatile memory 13 stores an operating system and the processing program of the present invention in advance. The ROM 12 or the nonvolatile memory 13 stores ATR (ATR information) and the like in advance.

  The CPU 11 functions as a setting change unit and a process stop unit of the present invention by executing the processing program of the present invention. As a result, when the CPU 11 receives a setting change request to the high speed communication (hereinafter referred to as “high speed communication request”) from the reading device 2 when the low speed communication is set, the CPU 11 accepts the setting change to the high speed communication. A response indicating that the change of the speed setting has been accepted (hereinafter referred to as “high-speed communication response”) is transmitted to the reading device 2 and the setting is changed from low-speed communication to high-speed communication. When the instruction received from the reading device 2 cannot be interpreted after the high-speed communication response is transmitted to the reading device 2, the CPU 11 performs processing without transmitting a retransmission request for the command to the reading device 2. It comes to stop. As a result, even if a communication error occurs when transitioning from the low-speed communication state to the high-speed communication state, it is possible to take measures for quickly returning to the normal (normal) communication state.

  Here, with reference to FIG. 2, the conventional behavior when a communication error occurs when transitioning from the low-speed communication state to the high-speed communication state will be described. FIG. 2 is a diagram illustrating an example of conventional behavior when a communication error occurs when transitioning from a low-speed communication state to a high-speed communication state. The conventional IC card and the reading device 2 start to behave from a communication state set to low-speed communication. In FIG. 2, the reading device 2 transmits a high-speed communication request to the IC card in order to set the communication state at high speed (step S101). When an IC card capable of responding to a high-speed communication request receives a high-speed communication request, a high-speed communication response including a message (message) indicating acceptance of a setting change to high-speed communication is performed by executing high-speed switching processing ( In other words, a speed setting change approval) is transmitted to the reading device 2 (step S102), and the setting is changed from low speed communication to high speed communication (that is, the speed setting is changed) immediately after the transmission is completed. Thereby, a high-speed communication response is transmitted by low-speed communication (that is, a low-speed response message is transmitted) to the reading device 2 that is still in the low-speed communication state, and is transmitted from the reading device 2 that has been switched to the high-speed communication state. Subsequent instructions can be received. However, when a noise is generated in a message indicating acceptance of the setting change included in the high-speed communication response transmitted from the IC card, and the signal shape becomes abnormal before reaching the reading device 2 from the IC card. (That is, when a communication error occurs), since it is not possible to confirm that the high-speed communication request transmitted from the reading device 2 has been accepted by the IC card, the communication speed of the reading device 2 is not changed and the low-speed communication Settings are maintained. Thus, when the reading device 2 in the low-speed communication state determines a communication error by the reception error determination process, it transmits a message retransmission request (command) to the IC card by low-speed communication (step S103). On the other hand, since the IC card that has received the retransmission request from the reading device 2 has already been changed to the high-speed communication state, the retransmission request from the reading device 2 cannot be interpreted (in other words, it cannot be accurately read). Thus, when the IC card determines a communication error by the reception error determination process, it transmits a command retransmission request to the reading device 2 by high-speed communication (step S104). Thereafter, such exchange is performed according to a preset number of retries. That is, the IC card and the reading device 2 fall into different interpretations and cannot return to a normal communication state without solving the error.

  Next, processing of the CPU 11 in the IC card 1 according to the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing an example of processing of the CPU 11 in the IC card 1 according to the present embodiment. The process illustrated in FIG. 3 is started, for example, when an ATR is transmitted to the reading device 2 in response to a reset signal received from the reading device 2.

  In step S1 shown in FIG. 3, the CPU 11 in the IC card 1 sets low-speed communication (that is, sets the communication speed to low speed). Next, when receiving a command from the reading device 2 (step S2), the CPU 11 determines whether or not the received command is a high-speed communication request (step S3). When it is determined that the received command is not a high-speed communication request (step S3: NO), the process proceeds to step S4. On the other hand, when it is determined that the received command is a high-speed communication request (step S3: YES), the process proceeds to step S6.

  In step S4, the CPU 11 executes the content of the received command. Next, the CPU 11 transmits an execution completion notice to the reading device 2 (step S5), and waits for the next command.

  On the other hand, in step S <b> 6, the CPU 11 transmits a high-speed communication response to the reading device 2. Next, the CPU 11 changes the setting from low speed communication to high speed communication (that is, sets the communication speed to high speed) (step S7). Next, when receiving a command from the reading device 2 (step S8), the CPU 11 determines whether or not the received command can be interpreted (step S9). When the received command can be interpreted (step S9: YES), the CPU 11 executes the content of the received command (step S10), transmits an execution completion notification to the reading device 2 (step S11), and waits for the next command. It becomes.

  On the other hand, if the received command cannot be interpreted (step S9: NO), the CPU 11 stops the process without transmitting a request for retransmission of the command to the reading device 2 (step S12). Thus, the IC card 1 according to the present embodiment starts a program that operates only immediately after transmitting a high-speed communication response. This may be activated based on a flag that records the transmission of the high-speed communication response, or may be activated continuously so as to operate immediately after the transmission of the high-speed communication response. Thus, immediately after transmitting a high-speed communication response, if an instruction that cannot be interpreted is received, the IC card 1 does not respond to anything and enters a stopped state. This stopped state may be a state in which the CPU 11 is initialized, or a state in which the software loops infinitely. The state in which the CPU 11 is initialized indicates the same state as the state in which the CPU 11 is waiting for the reset signal immediately after the power is turned on. As a state in which the CPU 11 is initialized, for example, there is a state in which a register value is initialized and a program counter indicates an abnormal value. Note that an error is immediately notified, for example, when the CPU 11 is initialized or when the software loops indefinitely. Thereby, a reset operation is performed by the user.

  As described above, according to the embodiment, when the IC card 1 receives a high-speed communication request from the reading device 2 when the low-speed communication is set, the IC card 1 transmits a high-speed communication response to the reading device 2, In addition, when the setting is changed from low-speed communication to high-speed communication, and the instruction received from the reader 2 cannot be interpreted thereafter, the processing is stopped without transmitting a retransmission request for the instruction to the reader 2. Even when a noise is generated in a message included in the high-speed communication response and a communication error occurs, it is possible to avoid the IC card 1 and the reading device 2 from being interpreted differently. That is, even when a communication error occurs when transitioning from the low-speed communication state to the high-speed communication state, the IC card 1 and the reading device 2 perform different behaviors from the intended purpose for the communication error. Therefore, it is possible to solve the problem that the error is not solved and to take a means for quickly returning to the normal communication state.

1 IC card 2 reader 11 CPU
12 ROM
13 Nonvolatile memory 14 RAM
15 I / O port

Claims (4)

An IC card that can be set by selecting either low-speed communication or high-speed communication with an external device,
When the low speed communication is set, when a request for changing the setting from the external device to the high speed communication is received, a response indicating acceptance of the setting change is transmitted to the external device, and the low speed communication is transmitted from the low speed communication to the high speed communication. A setting change means for changing the setting to
If the command received from the external device cannot be interpreted after the response is transmitted to the external device, a process stop means for stopping the process without transmitting a retransmission request for the command to the external device;
An IC card comprising:   The IC card according to claim 1, wherein the command transmitted from the external device after the response is transmitted to the external device is a command transmitted by low-speed communication. A computer included in an IC card that can be set by selecting either low-speed communication or high-speed communication with an external device.
When the low speed communication is set, when a request for changing the setting from the external device to the high speed communication is received, a response indicating acceptance of the setting change is transmitted to the external device, and the low speed communication is transmitted from the low speed communication to the high speed communication. A step to change the setting to
If the command received from the external device cannot be interpreted after the response is transmitted to the external device, the process stops without transmitting a retransmission request for the command to the external device;
An IC card processing program characterized in that A communication method performed by an IC card that can be set by selecting either low-speed communication or high-speed communication with an external device,
When the low speed communication is set, when a request for changing the setting from the external device to the high speed communication is received, a response indicating acceptance of the setting change is transmitted to the external device, and the low speed communication from the high speed communication is performed. A step to change the setting to
If the command received from the external device cannot be interpreted after the response is transmitted to the external device, the process stops without transmitting a retransmission request for the command to the external device;
A communication method comprising:

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