KR20010041244A - A radio frequency identification (rfid) security system having an rf emulating circuit - Google Patents

Abstract

Radio frequency identification (RFID) security 10 uses an electronic key 12 to store data. A reading mechanism 14 is provided, which is used to read a modulated signal with the data stored on the electronic key 12 when the electronic key 12 is connected to the reading mechanism 14. Emulating an RF energy signal on the electronic key 12 such that the reading mechanism 14 reads the data stored on the electronic key 12 when the electronic key 12 is connected to the reading mechanism 14. RF emulating circuit 16 is in turn connected to the read mechanism 14.

Description

A RADIO FREQUENCY IDENTIFICATION (RFID) SECURITY SYSTEM HAVING AN RF EMULATING CIRCUIT}

Electronic keys have long been used to prevent entry without access to fifteen authorized areas. Currently, there are several different types of electronic keys in the market. Each of these type keys work while they have some drawbacks.

One type of electronic key is a serial EEPROM 20 based electronic key. Serial EEPROM-based keys require four to five individual contacts to work. One contact is used for each of the power source, ground, clock, and data. Two contacts can be used for data transfer (ie one as input contact and one as output contact). Each of the plurality of contacts in the serial EEPROM based key must make an appropriate contact to transfer data with the clock through them. In apartment or hotel applications, users returning from the pool can put a wet key into the lock. This causes bad contact or disconnection between the contacts and prevents proper transfer of data and thereby prevents the lock from opening. In addition, inserting the wrong polarity key into the lock will cause damage to the lock electronics or EEPROM device, thereby making the key unusable. Moisture, polarity of insertion and wear and / or damage to the plurality of contacts are therefore a problem in this type of electronic key.

The second type of electronic key uses access control 10 RFID tags. In these types of keys, a card or tag is used in the reader for accessing the building. In most cases this type of electronic key is used for identification applications rather than security. Using this type of electronic key for security purposes (apartment and hotel locks) creates a problem. Because these types of keys are not very secure. Covert readers, even battery powered readers, can power up the tag and steal its code even if the tag is in the owner's pocket or purse without the owner's knowledge.

One way to solve the above problems associated with access control RFID tags is to have an encrypted electronic key. Some types of electronic keys include an encryption algorithm in the die itself. Some encryption algorithms will cause the code to be encrypted on the electronic key and change the code each time the key is read. These types of electronic keys are much more expensive than RFID tagging devices while preventing unauthorized "code grabbing". So security is achieved by spending money.

Therefore, there was a need to provide an improved RFID security device. The improved RFID security requires few connections for data transfer. The improved RFID security device should be more universal in polarity. The improved RFID security device must be resistant to the surrounding components. The improved RFID security device must also be able to be used for security and furthermore resistant to "code grabbing". The improved RFID security device would be a low cost solution to solving the above mentioned problems. The improved RFID security system will replace the RF portion of both the electronic key and the reading mechanism with simpler and less expensive circuits.

FIELD OF THE INVENTION The present invention generally relates to radio frequency identification (RFID) security devices and, in particular, to RFID security systems, where RFID tags and their complementary reader / question devices have a wired security bus to replace the RF portion of data communications. An RF emulating circuit is used.

1 is a simplified electrical block diagram of the present invention.

2 is a simplified electrical block diagram of one embodiment of the present invention.

3 is a simplified electrical diagram of one embodiment of the RF emulating circuit used in the present invention.

4 is a simplified electrical schematic diagram of a second tenth embodiment of the RF emulating circuit used in the present invention.

5 is an electrical block diagram of the simplified readout mechanism used in the present invention.

6A is a timing diagram of a modulated RF energy 15 carrier signal.

6B is a timing diagram of the demodulated baseband data signal.

According to one embodiment of the fifteen inventions, an object of the present invention is to provide an improved RFID security device. Another object of the present invention is to provide an improved RFID security device which requires little contact for data transfer. It is yet another object of the present invention to provide an improved RFID security device that is universal in polarity. It is yet another object of the present invention to provide an improved RFID security device that is resistant to surrounding components. It is a further object of the present invention to provide an improved RFID security device which can be used for security and furthermore resistant to "code grabbing". It is a further object of the present invention to provide an improved RFID security device which is a low cost solution to solving the above mentioned problems. It is another object of the present invention to provide an improved RFID security system that will replace the RF portion of both the electronic key and the reading mechanism with cheaper security.

According to an embodiment of the present invention, a radio frequency identification (RFID) security system is disclosed. The RFID security system uses an electronic key to store data. A reading mechanism is provided and is used to read a modulated signal having data stored on the electronic key when the electronic key is coupled to the reading mechanism. The RF emulating circuit is coupled to the reading mechanism to emulate an RF energy signal with the electronic key, thereby enabling the reading mechanism to read data stored in the electronic key when the electronic key is coupled to the reading mechanism.

Further objects, features, and advantages described above of the present invention will be apparent from the following description of the preferred embodiments of the present invention, particularly as illustrated in the accompanying drawings.

In FIG. 1, an improved RFID security system 10 (hereinafter system 10) is shown. The system 10 uses a radio frequency identification (RFID) tag device 12. The RFID tag device 12 is arranged as an electronic key and programmed to store data in the electronic key. When the RFID tag 12 is connected to the reading mechanism 14 via the RF emulating circuit 16, the data stored on the RFID tag device 12 will be read by the reading mechanism 14. If a suitable RFID tag 12 is inserted into the reading mechanism 14, the reading mechanism 14 will release the lock (not shown) or perform other actions depending on its particular application.

An energizing circuit needs to be connected to the RF tag device 12 and the reading mechanism 14 to read the data on the RFID tag device 12. In the present invention, the RF portion of both the RFID tag device 12 and the reading mechanism 14 has been replaced with cheaper circuits. The present invention uses RF emulating circuit 16. The RF emulating circuit 16 is used to emulate an RF energy carrier signal with the RFID tag device 12, where the "modulated" signal is then sent back to the reading mechanism 14. The reading mechanism 14 may filter out the carrier signal to read data stored on the RFID tag device 12.

2 shows an embodiment of how the RFID tag device 12 is arranged as an electronic key 18, in which like numerals and symbols represent identical components. The electronic key basically consists of two main components, an RFID tag device 12 and a connection device 20. As mentioned above, the RFID tag device 12 is used to store data read by the reading mechanism 14. The RFID tag device 12 is connected to the connection device 20. The connection device 20 is used to connect the RFID tag device 12 to the RF emulating circuit 16. When the electronic key 18 is connected to the RF emulating circuit 16, the RF emulating circuit 16 will emulate and send an RF energy carrier signal to the RFID tag device 12. The RFID tag device 12 is energized and activated by the incoming RF energy carrier signal. Once activated, the RFID tag device 12 returns the contents of its memory by modulating the incoming RF energy carrier signal. This "modulated" signal is then sent back to the reading device 14. The reading device 14 can then filter out the carrier signal to read the data stored in the RFID tag device 12.

3, where the same numbers and signals represent the same elements, an embodiment of the RF emulating circuit 16 is shown. The RF emulating circuit 16 will enable a simplified electronic key 18 and a simplified reading device 14 which form part of the present invention by replacing the electronic key of the prior art and the L-C circuit of the reading device. In one embodiment depicted in FIG. 3, the RF emulating circuit 16 uses a switching element 22. In a preferred embodiment of the invention, the switching element 22 is a transistor. The register 24 has a first terminal connected to the switching element 22 and a second terminal connected to the voltage source Vcc. The second register 26 has a first terminal connected to the switching element 22 and a second terminal connected to the connecting device 28. The connection device 28 connects the RF emulating circuit 16 to the electronic key 18 (FIGS. 1 and 2) when the electronic key 18 (FIGS. 1 and 2) is inserted into the reading device 14 (FIGS. 1 and 2). 2) is used to connect.

The first resistor 24 and the second resistor 26 form a voltage divider circuit. The switching element 22, together with the first register 24 and the second register 26, forms a drive circuit which simulates the carrier signal with the RFID tag device 12 (Figs. 1 and 2). If the resistors 24 and 26 are carefully selected and the switching element 22 is on resistance, then the RF emulating circuit 16 is sufficient for power up and proper operation of the RFID tag device 12. The RFID tag device 12 (FIGS. 1 and 2) will be driven with current and voltage.

When the RFID tag device (FIGS. 1 and 2) is powered by a carrier signal from the RF emulating circuit 16, the internal clock of the RFID tag device is operated in synchronization with the carrier signal, and the RFID tag device 12 Data stored in < RTI ID = 0.0 > This modulated RF signal is supplied to the simplified RFID reader 14 via the RF emulating circuit 16. In the embodiment depicted in FIG. 3, the on resistance of the RFID tag device 12 causes a square wave to overlap the carrier signal at point B (see FIG. 6A). The reading mechanism 14 (FIGS. 1 and 2) can then demodulate the signal and extract the tag data stream to obtain the data stored in the RFID tag device 12.

As an example, assume that the RFID tag device 12 has an on resistance of 10K ohms and an off resistance of 100K ohms. Both the first resistor 24 and the second resistor 26 have a resistance of 10K ohms. The voltage source will supply a voltage level of 5 volts. In operation, the switching element 22 will receive a carrier signal from the reading mechanism 14 (FIGS. 1 and 2). The carrier signal will have a high and low voltage level that activates and deactivates the switching element 22. (Ie, the carrier signal may have a voltage level from 0 to 5 volts.) When the switching element 22 is activated, the voltage at point B is a square wave with a voltage level of 0 volts. Will be. When the switching element is deactivated, the voltage at point B will be 4.2 volts for the off resistance level of the RFID tag device 12 or 1.7 volts for the on resistance level of the RFID tag device 12. The modulated carrier signal is shown in Figure 6A. The signal is demodulated to extract the data content of the memory in the RFID tag device 12. The simplified reader 14 also has a microcontroller (or processor) for decoding the demodulated signal. See Figures 6A and 6B for modulating and demodulating the signals, respectively. The carrier signal can be filtered out in the simplified reader 14 with a simple filter or comparator circuit. The 1.7 to 4.2 volt data stream (see Figure 6B) can then be driven into the data decoding circuit (microcontroller) without amplification.

In FIG. 4 where the same numbers and signals represent the same elements, a second embodiment of the RF emulating circuit 16 is shown. As mentioned above, the RF emulating circuit 16 and the simplified electronic key 18 (Figs. 1 and 2) form part of the present invention by replacing the LC circuitry of both the electronic key and the reading mechanism of the prior art. It will enable the reading mechanism 14 (FIGS. 1 and 2). In one embodiment depicted in FIG. 4, the RF emulating circuit 16 uses a single register 30. The register has a first terminal connected to the output of the read mechanism 14 (FIGS. 1 and 2) and a second terminal connected to the input of the read mechanism 14 (FIGS. 1 and 2). The second terminal of the register 30 is also connected to the connection circuit 28. The connection circuit 28 connects the RF emulating circuit 16 to the electronic key when the electronic key 18 (FIGS. 1 and 2) is inserted into the reading mechanism 14 (FIGS. 1 and 2). 18) (Figs. 1 and 2). The operation of the embodiment depicted in FIG. 4 will be operated in a manner similar to that disclosed in FIG. The carrier signal will be driven over the register 30. At point B, the voltage level will be one of three voltage levels again. The carrier signal can be filtered out with a simple filter or comparator circuit. When the RFID tag device 12 is activated, the modulated signal appears at point B. The data signal can be obtained by demodulating the output signal. The resulting signal can then be driven into the data decoding circuit without amplification.

In FIG. 5 where the same numbers and signals represent the same elements, the read mechanism 14 used in the present invention is shown. The reading mechanism 14 greatly simplifies the RFID readers currently being used to read RFID tag devices. The reading mechanism 14 is used to read data stored on the electronic key when the electronic key is connected to the reading mechanism 14. Reading mechanism 14 is on electronic key 18 (FIG. 2) when electronic key 18 (FIG. 2) is connected to reading mechanism 14 via RF emulating circuit 16 (FIGS. 1-4). One processor is used to read the data stream with the data stored in it. In the embodiment depicted in FIG. 5 the processor is a microcontroller. The timing device 34 is connected to the processor 32 and the RF emulating circuit 16. The timing device 34 is used to provide a clock signal to both the processor 32 and the RF emulating circuit 16. The timing device 34 may be an oscillator or other type of device capable of generating a clock signal. Signal passing circuit 36 (ie, demodulator) is coupled to processor 32 and RF emulating circuit 16. The signal passing circuit 36 is used to demodulate and filter out the carrier signal and to drive the data stream into the processor 32 without amplification. It should be noted that the comparison circuit or low pass filter connected to the reference signal is two examples of the signal passing circuit 36. In a preferred embodiment of the present invention a low pass filter is used.

While the invention has been shown and described in connection with particularly preferred embodiments, it is understood that other changes in the matters, forms and details may be made without departing from the spirit or scope of the invention. Will understand this.

Claims (20)

A radio frequency identification (RFID) security system, An electronic key for storing data; A reading mechanism for generating an RF clocking signal when the electronic key is coupled to a reading mechanism and for demodulating and reading a modulated signal having the data stored on the electronic key; And Converting the RF energy carrier signal into the electronic key such that the electronic key can modulate the RF energy carrier signal when the electronic key is coupled to the reading mechanism and that the reading mechanism can read the data stored on the electronic key. And a radio frequency emulating circuit coupled to said read mechanism for emulating. The electronic key of claim 1, wherein the electronic key is An RFID tag device for storing the data on the electronic key; And a key contact coupled to the RFID tag device for coupling the RFID tag device to the RF emulating circuit when the electronic key is coupled to the reading mechanism. The method of claim 1, wherein the reading mechanism is A processor for reading a demodulated baseband data signal having the data stored on the electronic key when the electronic key is coupled to the reading mechanism; A timing device coupled to the processor and the RF emulating circuit to provide clock signals to the processor and the RF emulating circuit; And A signal pass coupled to the processor and the RF emulating circuit to extract the demodulated baseband data signal and send the demodulated baseband data signal to the processor to read the data stored on the electronic key. A radio frequency identification security system comprising a circuit. 4. The system of claim 3, wherein said signal passing circuit is a low pass filter. 4. The system of claim 3, wherein said signal passing circuit is a comparator. The method of claim 1, wherein the RF emulating circuit A switching device coupled to the reading mechanism; A voltage divider circuit connected to the switching device; And And a voltage source coupled to the voltage divider circuit. 7. The radio frequency identification security system of claim 6 wherein the RF emulating circuit further comprises contacts coupled to the voltage divider circuit for coupling the electronic key to the rf emulating circuit. 7. The apparatus of claim 6, wherein the switching device comprises: a first terminal connected to the voltage divider circuit; A second terminal coupled to the reading mechanism; And a transistor having a third terminal connected to ground. 7. The circuit of claim 6, wherein the voltage divider circuit is A first resistor having a first terminal connected to the switching device and a second terminal connected to the voltage source; And And a second register having a first terminal coupled to said switching device and a second terminal coupled to said readout mechanism. 2. The radio frequency identification security system of claim 1, wherein the RF emulating circuit includes a register coupled to the read mechanism. 11. The system of claim 10, wherein said RF emulating circuit further comprises contacts coupled to said register for coupling said electronic key to said RF emulating circuit. An electronic key for storing data; A readout mechanism for demodulating and reading a modulated signal having said data stored on said electronic key when said electronic key is connected; and a radio frequency identification (RFID) security system comprising an RF emulating circuit, comprising: The electronic key is an RFID tag device for storing the data on the electronic key; And key contacts coupled to the RFID tag device for coupling the RFID tag device to the RF emulating circuit when the electronic key is coupled to the reading mechanism: The reading mechanism includes a processor for reading a demodulated baseband data signal having the data stored on the electronic key when the electronic key is coupled to the reading mechanism; A timing device coupled to the processor and the RF emulating circuit to provide clock signals to the processor and the RF emulating circuit; And a signal coupled to the processor and the RF emulating circuit to extract the demodulated baseband data signal and send the demodulated baseband data signal to the processor for the processor to read the data stored on the electronic key. Including the pass circuit: and An RF emulating circuit emulates an RF energy signal on the electronic key such that when the electronic key is coupled to the reading mechanism, the reading mechanism modulates the RF energy carrier signal and the reading mechanism reads the data stored in the electronic key. Radio frequency identification security system, characterized in that coupled to the reading mechanism for rating. 13. The system of claim 12, wherein said signal pass circuit is a low pass filter. 13. The system of claim 12, wherein said signal passing circuit is a comparator. 13. The circuit of claim 12 wherein the RF emulating circuit is A switching device coupled to the reading mechanism; A voltage divider circuit connected to the switching device; And And a voltage source coupled to the voltage divider circuit. 16. The system of claim 15, wherein said RF emulating circuit further comprises contacts coupled to said voltage divider circuit for coupling said electronic key to said RF emulating circuit. 16. The apparatus of claim 15, wherein the switching device comprises: a first terminal coupled to the voltage divider circuit; And a transistor having a second terminal coupled to said readout mechanism; and a third terminal coupled to ground. 16. The circuit of claim 15 wherein the voltage divider circuit is A first resistor having a first terminal connected to the switching device and a second terminal connected to the voltage source; And And a second register having a first terminal coupled to the switching device and a second terminal coupled to the reading mechanism. 13. The system of claim 12, wherein said RF emulating circuit includes a register coupled to said read mechanism. 20. The system of claim 19, wherein said RF emulating circuit further comprises contacts coupled to said register for coupling said electronic key to said RF emulating circuit.