KR20030097044A - Apparatus and method for discrimination rf card type - Google Patents

Abstract

PURPOSE: A device and a method for discriminating a type of an RF(Radio Frequency) card are provided to discriminate a type-A card or a type-B card by receiving a signal from the card and analyzing the signal with a difference of a physical communication method in the same device. CONSTITUTION: An RF signal is inputted from the RF card entered an operation area of an antenna. The RF signal is clipped to a constant level in order to make an envelope have a positive value. An output signal is low-frequency filtered. The output signal is integrated. If an integration value is above a standard value, the RF card is decided as the type-A card. If the integration value is below the standard value, the RF card is decided as the type-B card.

Description

RF card type discriminator and method {APPARATUS AND METHOD FOR DISCRIMINATION RF CARD TYPE}

Looking at the communication process between a commonly used RF card and a terminal (bus terminal, subway terminal, charging terminal, etc.), when the user brings the RF card to the antenna effective area of the terminal, the RF card is a radio signal to indicate its existence Release. The next terminal sends a REQ (request) signal to the card and the card performs an initialization operation such as sending an ATQ (answer to request) signal to the terminal. After initialization, the terminal and the card execute the anti-collusion loop using the card's own serial number. An anti-collusion loop is performed to select one of a plurality of cards when two or more cards are simultaneously in the terminal antenna effective area. In other words, the communication is made only to the card and the terminal having a specific serial number. Next, the terminal performs an authentication operation (3-pass authentication in the case of the Mifare type card) using the internal security module (SAM) to access the memory area (EEPROM) inside the card and perform the corresponding operation.

The above description is the operation of Philips Mifare RF card. RF card, which is widely used mainly for transportation cards, is the most commonly used Mifare card of Philips. In addition, ISO established ISO14443A (part1 to part4) as a standard for a typeA type card including a Philips Mifare method, and a typeB type card having a different communication method from the cards was also enacted as ISO14443B. However, although the typeA standard card includes the Mifare method, the two are only the same physical communication method in the wireless area from part1 to part3, and the length of the card serial number and the encryption protocol algorithm are different from each other. In use, they are treated in completely separate ways. In other words, there are three types of Mifare cards, typeA standard cards, and typeB standard cards. In the ISO14443A standard, the Mifare method and the typeA method are handled identically to the physical rules and the card selection method part1 to part3, and the part4 which defines the communication protocol between the terminal and the card is divided into the typeA method and the other method (Mifare method). The Mifare card has a simple structure, is cheap, and is widely used. However, in the future, it may be assumed that a typeA card or a typeB card with improved functionality will replace it.

For replacement, existing cards must be compatible for economic reasons, so they can be used in practice. However, in the conventional technology, a typeA card and a Mifare card with the same physical communication method cannot be used interchangeably in the same terminal, and compatibility with other typeB cards with different physical communication methods is further required. However, with existing technology, it is possible to simply collect the modules for each method in one terminal and designate which method each time it is used to perform the processing according to each method, which is inconvenient in the transportation card area that requires quick processing. There is no time, and the user has to know the type of card he has.

The present invention has been made to overcome the problems of the existing technology, the object of the present invention is to focus on the difference in the physical communication method of the same device (for example, traffic card bus terminal) by receiving a signal from the card to analyze the typeA card The present invention provides a method for distinguishing between a typeB card and a typeB card.

Another object of the present invention is to provide a method for discriminating whether a card determined as a typeA card by the analysis of the physical communication method is a card of Mifare type or a card conforming to all general standards of typeA of ISO.

Still another object of the present invention is to provide a card type discriminating apparatus in which the above distinguishing method is used, for example, a bus terminal or a subway terminal.

1 is a block diagram showing the structure of a card type discriminating apparatus of the present invention.

Figure 2 (a) is a view showing a state of a radio signal that the terminal sends to the typeA card.

Figure 2 (b) is a diagram showing the state of the radio signal sent to the typeA card to the terminal.

Figure 2 (c) is a view showing the state of the output signal after the radio signal of the typeA card passes the clipping circuit of the present invention.

FIG. 2 (d) is a diagram illustrating the output signal of the clipping circuit after the output signal of the clipping circuit passes through the filtering circuit LPF.

FIG. 2 (e) is a diagram illustrating the output signal of the type A card after the output signal of the filtering circuit passes through the clipping circuit.

FIG. 2 (f) is a diagram illustrating the output signal of the clipping circuit after the output signal of the clipping circuit passes through the integration circuit.

Figure 3 (a) is a view showing the state of the radio signal that the terminal sends to the typeB card.

Figure 3 (b) is a diagram showing the state of the radio signal sent to the typeB card to the terminal.

Figure 3 (c) is a view showing the state of the output signal after the radio signal of the typeB card passes the clipping circuit of the present invention.

FIG. 3 (d) shows the output signal of the clipping circuit after the output signal of the clipping circuit passes through the filtering circuit LPF.

FIG. 3 (e) is a diagram illustrating the output signal after the output signal of the filtering circuit passes through the clipping circuit in the case of a typeB card.

FIG. 3 (f) is a diagram illustrating the output signal after the output signal of the clipping circuit passes through the integration circuit in the case of a typeB card.

4 is a flowchart showing the procedure of the card type discrimination method of the present invention.

5 is a flowchart illustrating a procedure of another card type discriminating method of the present invention.

Card type discrimination method of the present invention comprises the steps of receiving an RF signal from the RF card entered into the operating area of the antenna; Level-clipping the RF signal received in the step so that the envelope of the RF signal has a positive value; Low pass filtering the output signal of the clipping step; Integrating the output signal of the filtering step; When the integral value of the integration step is greater than or equal to the reference value, it is determined as a typeA card, and if less than the reference value, it provides a method for distinguishing an RF card.

The method may further include clamping the output signal of the filtering step prior to the integrating step so that the integral value of the portion where the intermediate frequency of the output signal exists is zero. It provides a method of distinguishing an RF card.

In addition, in each of the two different methods, if it is determined that the typeA, the anti-collusion loop to execute a SELECT command for the selected RF card; Receiving a response to the SELECT command from an RF card; If the sixth bit of the first byte of the response signal is 0, the card is determined to be a Mifare card, and if it is 1, it is determined to be a typeA card conforming to all of the ISO14443A standard. Provide a method.

An RF card discriminating apparatus (terminal) used in the discriminating method of the present invention comprises: an RF interface unit including an RF antenna that wirelessly interfaces with an RF card; And a clipping circuit for clipping the high frequency signal received from the RF interface unit, a filtering circuit for filtering the clipped signal, and an integration circuit for integrating the filtered signal, and physically analyzing the high frequency signal received from the interface unit. It characterized in that the typeA / B determination unit for distinguishing whether the typeA card or typeB card.

The RF card responds to the SELECT signal of the terminal while executing a card initialization and an anti-collusion loop on the card determined as type A in the type A / B determining unit together with the RF interface unit and the type A / B determining unit. It is characterized by consisting of the Mifare / typeA determination unit by analyzing the Mifare type card, whether the typeA card according to all ISO14443A standard.

With reference to the accompanying drawings will be described in detail the structure and operation of the embodiment of the present invention. Figure 4 shows the procedure flow of an example of the card type discrimination method according to the present invention.

First, it is determined whether it is a typeA card or a typeB card based on a difference in physical communication methods. When the RF card enters the active region of the terminal antenna 22, the appearance of the radio signal emitted is as shown in Figs. 1 (b) and 2 (b). That is, it has a high frequency component (shown in black in the drawing) that is a main carrier and an intermediate frequency component that modulates a high frequency (that is, the main high frequency has been modulated to an intermediate frequency). As shown in FIG. 1 (b), the typeA card adjusts the region modulating to the intermediate frequency and the region without the intermediate frequency according to the value of each bit, and as shown in FIG. Is always modulated to intermediate frequency, and the phase of the intermediate frequency component is shifted by 180 degrees depending on the value of each bit.

In the present invention, in order to determine the type of the card being used in the physical difference of the signal emitted from each of these cards, first, the signal emitted from the card is clipped to a certain level. You can also half-wave rectify instead of clipping, which is the same as setting the clipping level to zero. The upper clipping level adjusts so that the minimum value of the envelope of the clipped signal is greater than zero. The output of the clipping circuit 32 is the same as that of FIGS. 1C and 2C. Next, the output of the clipping circuit 32 is low pass filtered. At this time, the DC component and the intermediate frequency pass, the high frequency component is removed, and as a result, the envelope of the input signal appears as an output, and the output of the low frequency filtering circuit 34 is as shown in FIGS. 1 (d) and 2 (d). Next, the output value of the filtering circuit 32 is clamped at a constant level, and the clamping level is adjusted so that the integral value of the intermediate frequency present portion is canceled to zero, and its output is as shown in Figs. 1 (e) and 2 (e). Next, the output signal of the clamping circuit 35 is integrated for a predetermined time. In this case, the predetermined time is a time at which a few bits are expressed. In this step, the predetermined time may be integrated. Next, as shown in FIGS. 1 (f) and 2 (f), if the output value of the integrating circuit 36 is less than or equal to the reference value, it is determined as a typeA card, and if it is less than the reference value, it is determined as a typeB card. Since the input signal of the integrating circuit 36 of the typeB card is composed mostly of sine wave components (intermediate frequency), the output value is close to zero, but since the input signal of the integrating circuit 36 of the typeA card has a substantial DC component, the output value is It will have a positive value with a certain size. The present invention can be implemented to deliver the output of the filtering circuit 34 directly to the integrating circuit 36 without having the clamping circuit 35, but as described above for accuracy and ease of determination of the output value of the integrating circuit 36. Preferably, the clamping circuit 35 is provided so that the final output value of the typeB card is zero.

As shown in Fig. 1 (a) and 2 (b), since the shape of the radio signal that the terminal sends to the card is also different from the typeA (including Mifare) and typeB, the terminal is a different radio depending on the type of card determined The signal must be used to communicate with the card. For the card proved to be typeB by the above process, it is possible to process the operation by communicating with the terminal according to the standard protocol of typeB, but the card proved to be typeA must again determine whether it is a typeA or Mifare card conforming to ISO standards. do. This is because the wireless signal used by the two types of cards is the same, but the protocol rules used when communicating with the terminal are different. Therefore, it is necessary to determine which method the terminal communicates with the card using a protocol suitable for the card. This is because it becomes possible. Since the difference between these two approaches lies in the protocol-to be exact, the protocol after the end of the anti-collusion loop (anti-collusion loop break)-let's look at how to determine the card in the protocol.

In order to explain the Mifare determination process of the present invention, the card recognition process of the terminal is described again. When the card enters the active area of the terminal antenna 22, the card sends its serial number to the terminal along with the initialization operation. In case multiple cards are contacted at the same time, the terminal selects one card (serial number) by executing an anti-collusion loop with the serial number. The terminal sends a SELECT signal indicating that the card of the selected serial number is to perform communication, and the card sends a 1-byte select acknowledgment (SAK) signal in response. In the SAK signal, the sixth bit is "1" in the case of a typeA card conforming to all of the ISO14443A standard (parts 1 through 4), and in the case of "0", the conventional Mifare method is followed. Therefore, with the sixth bit of this SAK signal, it is determined whether the used card is a Mifare type card or a card conforming to all of the ISO14443A standard. However, the old version of the Mifare type card also sends the EEPROM area size value in kbytes in the card to the terminal in response to the terminal's SELECT signal. However, all of these Mifare cards have an internal EEPROM area size of 16 kbytes or less (i.e., if the sixth bit of the response to the SELECT is "1", this bit cannot be "1"). In accordance with the determination method of the present invention, it can be determined whether the Mifare card or the typeA card conforming to all of the ISO14443A standard. In addition, as shown in FIG. 5, another decision method for the Mifare / typeA method may be determined with the magnitude of the card response to the SELECT signal. In accordance with all ISO14443A standards (particularly part4), the SAK signal for a SELECT signal shall be accompanied by two bytes of cyclic redundancy checking (CRC) in one byte. On the other hand, in the old version of Mifare, only 1 byte of the EEPROM area size value in the card for the SELECT signal is transmitted to the terminal. Therefore, if the size of the response data of the card used for the SELECT signal of the terminal is 3 bytes, it is determined that the card conforms to all of the ISO14443A standard, and if it is 1 byte, it is determined that the card is Mifare type.

As shown in FIG. 3, the RF card type discriminating apparatus (bus terminal, subway terminal, etc.) of the present invention for implementing the method includes an RF interface including an RF antenna 22 that wirelessly interfaces with the RF card. Section 20; A clipping circuit 32 for clipping the high frequency signal received from the RF interface unit 20, a filtering circuit 34 for filtering the clipped signal, and an integrating circuit 36 for integrating the filtered signal, A typeA / B determination unit 30 which physically analyzes the high frequency signal received from the interface unit to distinguish between a typeA card and a typeB card; The typeA / B determination unit 30 analyzes the response of the RF card to the SELECT signal of the terminal while executing the card initialization and anti-collapse loop, and whether the card is a Mifare type card or the ISO14443A standard. Mifare / typeA determination unit 40 for determining whether the typeA card according to, and may further include a control unit 10 for adjusting the operations of the respective parts, the typeA / B determination unit 30 is clamping It is preferable that a clamping circuit 35 is provided at a predetermined level before the output signal of the filtering circuit 34 is input to the integrating circuit 36. As shown in Figs. 1 (e) and 2 (e), the clamping level is preferably such that the integral values of the intermediate frequency portions cancel each other to be 0. In this case, Figs. 1 (f) and 2 (f) As shown in Fig. 2), the integral value of typeA has a positive value to some extent, but the integral value of typeB is close to 0, making the judgment more certain.

The RF interface unit 20 is composed of an RF antenna 22 for receiving a signal of the RF card, and an RF module for converting a radio signal into a digital signal, and the type A / B determination unit 40 is the RF interface unit ( 20) receives the analog radio signal, not the digital signal, and determines whether the card being used is typeA / typeB. The Mifare / type A determination unit 40 is activated when the determination result of the type A / B determination unit 30 is type A, and receives a signal converted into a digital signal from the RF interface unit 20 and is in use. Final judgment of the type of.

According to the type discriminating device and the distinguishing method of the RF card according to the present invention, for each Mifare type card, typeA card, and typeB card used in one device (e.g., bus terminal, subway terminal), the card is automatically It is useful to provide an automatic discrimination method of a card type to determine a type and to appropriately perform a radio wave signal system and a transmission / authentication protocol suitable for the type.

Claims (5)

Receiving an RF signal from an RF card entered into an operation region of the antenna; Level-clipping the RF signal received in the step so that the envelope of the RF signal has a positive value; Low pass filtering the output signal of the clipping step; Integrating the output signal of the filtering step; And determining the typeA card if the integral value of the integration step is equal to or greater than the reference value, and determining the typeB if the integral value is less than the reference value. 2. The method of claim 1, further comprising clamping the output signal of the filtering step before the integrating step such that the integral value of the portion where the intermediate frequency of the output signal exists is zero. How to distinguish RF card type. 3. The method of claim 1 or 2, further comprising: executing a anti-collusion loop to send a SELECT command to the selected RF card if it is determined as typeA; Receiving a response to the SELECT command from an RF card; If the sixth bit of the first byte of the response signal is 0, it is determined as a Mifare type card, and if 1, it is determined as a typeA card conforming to all of the ISO14443A standard. Way. An RF interface unit including an RF antenna that wirelessly interfaces with the RF card; And a clipping circuit for clipping the high frequency signal received from the RF interface unit, a filtering circuit for filtering the clipped signal, and an integration circuit for integrating the filtered signal, and physically storing the high frequency signal received from the interface unit. RF card type discrimination device comprising a typeA / B determination unit for distinguishing the typeA card or typeB card as the output value of the integrated circuit analyzed by. An RF interface unit including an RF antenna that wirelessly interfaces with the RF card; And a clipping circuit for clipping the high frequency signal received from the RF interface unit, a filtering circuit for filtering the clipped signal, and an integration circuit for integrating the filtered signal, and physically storing the high frequency signal received from the interface unit. A typeA / B judging unit for discriminating whether the typeA card is a typeB card or not; The typeA / B determination unit analyzes the response of the RF card to the SELECT signal of the terminal while executing the card initialization and anti-collusion loop, and is a Mifare type card or a typeA complying with all of the ISO14443A standards. RF card type discriminator, characterized in that consisting of Mifare / type A determination unit for determining whether the card.