JP4957209B2 - IC card communication module, IC card communication method, and computer program - Google Patents

Description

  The present invention relates to a technique for communicating with an IC card via USB, and more particularly, to a technique for adjusting the amount of communication with the IC card.

  A SIM (Subscriber Identity Module) in which the vicinity of an IC chip mounted on an IC card is cut into a strip shape is incorporated in a device and used as a device for encrypting / decrypting data used in the device.

  As an example of incorporating a SIM into a device, the same applicant has applied for a system in which a SIM is mounted on a monitoring camera 2 that can be connected to the Internet, and a moving image captured by the monitoring camera 2 is encrypted by the SIM (Patent Document 1). .

  By combining the device such as the monitoring camera 2 and the SIM, there is a merit that the change of the device to be performed for encrypting the data can be minimized and the encryption algorithm can be easily exchanged.

However, the communication speed of the SIM is 9600 bps as standard, which is very slow compared to the communication speed of a general computer peripheral device and the communication speed of the network. Since time becomes a bottleneck, an IC chip that is equipped with a USB interface as disclosed in Patent Document 2 and is capable of dramatically improving the communication speed has been developed.
Japanese Patent Application No. 2005-108601 Special table 2003-532936 gazette

  Certainly, the communication speed between the device and the IC card is improved by using the USB interface as the communication interface of the IC chip. However, since the peripheral devices connected by USB are different for each device, the maximum amount of data (data) that can be exchanged with the IC card varies depending on the situation at that time.

  Accordingly, the present invention provides an IC card that can adjust the amount of data (data) exchanged with the IC card according to the situation when communicating with the IC card when the device and the IC card communicate with each other via USB. An object is to provide a communication module, an IC card communication method, and a computer program.

  A first invention that solves the above-described problem is an IC card communication module that is incorporated in a device that communicates with an IC card via USB, and that controls communication with the IC card that is mounted on the device. The communication module starts with an initial value for the amount of communication with the IC card, increases the amount of communication by adding a constant to the amount of communication, and communicates with the IC card a certain number of times each time the amount of communication is changed. And a communication amount adjusting means for measuring the communication time when the measured communication time is the shortest and setting the communication amount when the measured communication time is the smallest as an optimum value.

  Further, the second invention is an IC card communication method for communicating with an IC card via USB, wherein the IC card communication method starts from an initial value for the amount of communication with the IC card and sets a constant for the amount of communication. Each time the communication amount is increased by adding, and the communication amount is changed, the communication time when communicating with the IC card a certain number of times is measured, and the communication amount when the measured communication time becomes the smallest Is provided with a communication amount adjustment step in which the optimal value is set.

  Further, the third invention is a computer program that is incorporated in a computer that communicates with an IC card via USB and controls communication with the IC card, and starts from an initial value for the amount of communication with the IC card. The communication amount was increased by adding a constant to the communication amount, and each time the communication amount was changed, the communication time when communicating with the IC card a certain number of times was measured, and the measured communication time was the smallest It is a computer program for causing the device to function as a communication amount adjusting means for setting the communication amount at the time to an optimum value.

  In the present invention, an IC card means a card medium on which an IC chip is mounted, and an interface for communicating with a host device does not ask for contact / non-contact. Further, the IC card according to the present invention includes a SIM or UIM obtained by cutting the periphery of the IC chip into a strip shape.

  According to the above-described invention, when interacting with an IC card, the communication amount is gradually increased starting from a small amount of communication, so that it can be adjusted according to the situation when communicating with the IC card.

  From here, as an example of a computer device incorporating the IC card communication module according to the present invention, a mode when the device is a surveillance camera will be described. FIG. 1 is a diagram for explaining a surveillance camera 2 incorporating an IC card communication module 20 according to the present invention.

  In order to prevent the leakage of the video file of the video captured by the monitoring camera 2 and the alteration of the video file, the SIM 1 is used as an encryption module for encrypting the video file of the video. The file is divided into small packet data and transmitted to the SIM 1, and the SIM 1 records the packet data encrypted using DES in the memory card 3.

  The SIM 1 attached to the monitoring camera 2 includes a USB interface as a communication interface, and the IC card communication module 20 according to the present invention is incorporated in the monitoring camera 2 in order to communicate with the SIM 1 using the USB interface.

Further, SIM1 is an IC card to which the invention disclosed in Patent Document 3 is applied. SIM1 has two modes, an ISO mode and a data mode, and the SIM1 mode is changed from the ISO mode to the data mode. A mode change command 10 which is a command is provided.
Japanese Patent Application No. 2006-175441

  FIG. 2 is a diagram illustrating the SIM1 mode. As shown in FIG. 2, in the ISO mode, when the APDU is exchanged between the SIM 1 and the monitoring camera 2 and the SIM 1 receives the command APDU of the mode change command 10 in the ISO mode, the SIM 1 mode is changed from the ISO mode to the data. In the data mode, only the packet data and the ciphertext of the packet data are exchanged.

  The IC card communication module 20 provided in the monitoring camera 2 reduces the size of the packet data serving as a communication amount when exchanging with the SIM 1 when the moving image file captured by the monitoring camera 2 is encrypted and stored in the memory card 3. It has a function of starting transmission from the size, gradually increasing the size of the packet data, and adjusting the size of the packet data to be transmitted to the SIM 1 to an optimum value.

  FIG. 3 is a diagram illustrating an example of a command APDU of the mode change command 10 for causing the SIM 1 to transition to the data mode.

  As shown in FIG. 3, in the present embodiment, the structure of the command APDU of the mode change command 10 is the case 3 command structure of the ISO / IEC7816 standard, and a command header composed of CLA, INS, P1, and P2. , Lc and a data field.

  CLA and INS included in the command APDU header of the mode change command 10 are data for identifying the command APDU. In this embodiment, the CLA of the mode change command 10 is “D0h” and the INS is “00h”. It is.

  P1 and P2 included in the header of the command APDU of the mode change command 10 are parameters when the mode change command 10 is executed. In this embodiment, neither P1 nor P2 is used, and the values thereof are fixed. “00h”.

  Lc of the body of the mode change command 10 indicates the length of data included in the data field. The data field includes the size of packet data (2 bytes) transmitted in the data mode and the number of packet data transmissions (2 Byte).

  FIG. 4 is a diagram illustrating an example of a response APDU of the mode change command 10. When the number of packet data encrypted by the SIM 1 reaches the number of transmissions indicated by the mode change command 10, the SIM 1 mode is set to the ISO mode. And the response APDU including the ciphertext of the packet data received last is generated as SW and the body indicating the processing result of the mode change command 10 as a trailer.

  Next, the IC card communication module 20 incorporated in the monitoring camera 2 will be described. FIG. 5 is a diagram for explaining the IC card communication module 20 incorporated in the monitoring camera 2.

  The IC card communication module 20 is realized by an interface board on which electronic components such as a USB controller are mounted. The IC card communication module 20 includes a USB controller 201 that controls a USB interface 21 that is a physical interface, A service provider 200 is provided as an interface when the monitoring camera 2 uses the function of the SIM 1 via the image processing board of the monitoring camera 2 and the USB controller 201.

  The USB controller 201 has a function of monitoring the USB interface 21 and realizing a USB communication protocol. The service provider 200 provides an API (API: Application Program Interface) when the image processing board of the monitoring camera 2 uses the function of the SIM1, and the packet data transmitted from the image processing board of the monitoring camera 2 is transmitted to the SIM1. It has a function of encrypting the encrypted packet data and returning the encrypted packet data to the image processing board of the monitoring camera 2.

  The service provider 200 has a function of a traffic volume adjusting unit according to the present invention. When transmitting packet data to the SIM 1, the service provider 200 starts transmission from a small size packet data, gradually increases the size of the packet data, The optimum size of the packet data to be transmitted is checked, and the packet data is transmitted to the SIM 1 with the optimum size.

  The function of the traffic volume adjusting means possessed by the service provider 200 is implemented by a computer program that is incorporated in a CPLD (Complex Programmable Logic Device) mounted on the IC card communication module and functions as the traffic volume adjusting means.

  FIG. 6 is a flowchart showing an operation procedure of the IC card communication module 20. The first step S1 executed in this procedure is a step of initializing variables used when adjusting the size of packet data.

  In this step, the variables when transmitting packet data to the SIM 1 are the packet size, the lower limit value / upper limit value of the packet size, the optimum packet size, the minimum communication time, and the measured communication time.

  The packet size is a variable in which the size of the packet data to be transmitted to the SIM 1 is substituted when the SIM 1 is in the data mode. When the service provider 200 of the IC card communication module 20 transmits the packet data to the SIM 1 Starting from the lower limit value of the packet size, the packet size is gradually increased to adjust the packet size to the optimum value.

  The measurement communication time is the time required for communication with the SIM 1 when the packet data is transmitted to the SIM 1 and encrypted, that is, the time required for transmitting the packet data, and the ciphertext of the packet data is received from the SIM 1. The minimum communication time is substituted when the packet data size is changed, and the smallest measured communication time is substituted, and the packet size at the smallest measured communication time is the optimum packet size. Is assigned to

  Here, the lower limit value of the packet size is 64 bytes and the upper limit value is 1024 bytes. In this step, the packet size is set to the lower limit value. The initial value of the optimum packet size is set to 0 bytes, and the minimum communication time is set to 2 to the 31st power.

  The next step S2 is a step of transmitting the mode change command 10 to the SIM1. In this step, the service provider 200 of the IC card communication module 20 adjusts the size of the packet data to be transmitted to the SIM 1 to the optimum value, and the mode change command 10 with the number of transmissions being 10 times and the packet size being the packet size. To SIM1.

  In this step, when the service provider 200 of the IC card communication module 20 transmits the mode change command 10, the SIM1 mode changes from the ISO mode to the data mode.

  The next step S3 is a step of transmitting the packet data to the SIM 1 and encrypting the packet data. In this step, the service provider 200 of the IC card communication module 20 initializes the measured communication time, and then transmits the packet data having the size set by the mode change command 10 in step S3 to the set transmission count (here, 10 times). ) And the packet data is encrypted by the SIM 1 that has transitioned to the data mode.

  In this step, the service provider 200 of the IC card communication module 20 spends time spent transmitting packet data and receiving ciphertext of packet data transmitted from the SIM 1 every time packet data is transmitted to the SIM 1. Add time to measured communication time. That is, the measured communication time after this step is executed is the total communication time spent when packet data is encrypted 10 times.

  The next step S4 is a step of comparing the minimum communication time with the measured communication time. In this step, when the measured communication time is smaller than the minimum communication time, the process proceeds to step S5. When the measured communication time is equal to or longer than the minimum communication time, the process proceeds to step S6.

  Step S5 is a step of updating the value of the minimum communication time and the optimum packet size. In this step, the value of the measured communication time obtained in step S3 is substituted for the minimum communication time, and the packet size used in step S3 is changed. Substitute a value for the optimal packet size. After this step is executed, the process proceeds to step S6.

  Step S6 is a step of updating the packet size. In this step, the service provider 200 of the IC card communication module 20 adds a constant (here, 64 bytes) to the packet size in order to gradually increase the packet size.

  The next step S7 is a step of comparing the packet size value with the upper limit value of the packet size. In this step, if the packet size value is smaller than the upper limit value of the packet size, the process returns to step S2, and otherwise, the process proceeds to step S8.

  Step S8 is a step of transmitting the mode change command 10 to the SIM1. In this step, the service provider 200 of the IC card communication module 20 transmits to the SIM 1 a mode change command 10 in which the number of transmissions of the data field is unlimited and the size of the packet data in the data field is the value of the optimal packet size.

  The next step S9 is a step in which the service provider 200 of the IC card communication module 20 transmits packet data to the SIM 1 and encrypts the packet data. In this step, the service provider 200 of the IC card communication module 20 transmits packet data of the optimum packet size to the SIM 1 until the SIM 1 is deactivated, and causes the SIM 1 that has transitioned to the data mode to encrypt the packet data.

  The present invention is not limited to the embodiments described so far, and various modifications and changes can be made, and these are also within the equivalent scope of the present invention.

  In the embodiment described above, the amount of communication with the IC card (SIM1) is the size of packet data that does not include a command header. However, the command APDU that includes the command header is used, and the size of the data included in the command APDU is optimal. It can also be adjusted to a value.

The figure explaining the surveillance camera incorporating an IC card communication module. The figure explaining the mode of SIM. The figure which showed an example of command APDU of a mode change command. The figure which showed an example of the response APDU of a mode change command. The figure explaining an IC card communication module. The flowchart which showed the procedure of operation | movement of an IC card communication module.

Explanation of symbols

1 SIM
10 mode change command 2 surveillance camera 20 IC card communication module 200 service provider 201 USB controller 21 USB interface

Claims (3)

  An IC card communication module that is incorporated in a device that communicates with an IC card via USB and controls communication with the IC card that is mounted on the device, wherein the IC card communication module communicates with the IC card. Starting from the initial value, the communication amount is increased by adding a constant to the communication amount, and each time the communication amount is changed, the communication time when communicating with the IC card a certain number of times is measured, and the measured An IC card communication module, comprising: a communication amount adjusting unit that optimizes the communication amount when the communication time becomes the shortest.   An IC card communication method for communicating with an IC card via USB, wherein the IC card communication method starts from an initial value for the amount of communication with the IC card, and increases the amount of communication by adding a constant to the amount of communication. Then, each time the communication amount is changed, the communication time when the communication with the IC card is performed a certain number of times is measured, and the communication amount adjustment with the communication amount when the measured communication time becomes the smallest as the optimum value An IC card communication method comprising a step. A computer program that is incorporated in a computer that communicates with an IC card via USB and controls communication with the IC card, starting from an initial value for the amount of communication with the IC card, and adding a constant to the amount of communication Each time the communication amount is increased and the communication amount is changed, a communication time when communicating with the IC card a certain number of times is measured, and the communication amount when the measured communication time becomes the smallest is an optimum value. A computer program for causing the device to function as communication amount adjusting means.

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