EP0807733A2 - Identification signal checking apparatus and methods - Google Patents

Identification signal checking apparatus and methods Download PDF

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Publication number
EP0807733A2
EP0807733A2 EP97303313A EP97303313A EP0807733A2 EP 0807733 A2 EP0807733 A2 EP 0807733A2 EP 97303313 A EP97303313 A EP 97303313A EP 97303313 A EP97303313 A EP 97303313A EP 0807733 A2 EP0807733 A2 EP 0807733A2
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EP
European Patent Office
Prior art keywords
signal
random number
identification signal
identification
memory unit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97303313A
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German (de)
French (fr)
Other versions
EP0807733A3 (en
Inventor
Hiroyuki Sony Corp. Intell. Prop. Div. Takamatsu
Yoshio Sony Corp. Intell. Prop. Div. Harada
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Sony Corp
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Sony Corp
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Publication date
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Publication of EP0807733A2 publication Critical patent/EP0807733A2/en
Publication of EP0807733A3 publication Critical patent/EP0807733A3/en
Withdrawn legal-status Critical Current

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    • GPHYSICS
    • G07CHECKING-DEVICES
    • G07CTIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
    • G07C9/00Individual registration on entry or exit
    • G07C9/00174Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys
    • G07C9/00309Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated with bidirectional data transmission between data carrier and locks
    • GPHYSICS
    • G07CHECKING-DEVICES
    • G07CTIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
    • G07C9/00Individual registration on entry or exit
    • G07C9/00174Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys
    • G07C9/00309Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated with bidirectional data transmission between data carrier and locks
    • G07C2009/00388Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated with bidirectional data transmission between data carrier and locks code verification carried out according to the challenge/response method
    • G07C2009/00396Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated with bidirectional data transmission between data carrier and locks code verification carried out according to the challenge/response method starting with prompting the keyless data carrier
    • GPHYSICS
    • G07CHECKING-DEVICES
    • G07CTIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
    • G07C9/00Individual registration on entry or exit
    • G07C9/00174Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys
    • G07C9/00309Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated with bidirectional data transmission between data carrier and locks
    • G07C2009/00412Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated with bidirectional data transmission between data carrier and locks the transmitted data signal being encrypted
    • GPHYSICS
    • G07CHECKING-DEVICES
    • G07CTIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
    • G07C9/00Individual registration on entry or exit
    • G07C9/00174Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys
    • G07C2009/00753Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated by active electrical keys
    • G07C2009/00769Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated by active electrical keys with data transmission performed by wireless means
    • G07C2009/00785Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated by active electrical keys with data transmission performed by wireless means by light

Definitions

  • the present invention relates to identification signal checking apparatus and methods, such as those suitable for use in a keyless entry system.
  • a keyless entry system has been proposed.
  • infrared rays or radio waves are used to transmit an identification signal from a key apparatus side to a lock apparatus side for the locking or the unlocking thereof.
  • Such keyless entry system employs a one-way communication in which the key apparatus side constantly transmits the same identification signal. Therefore, when this communication is intercepted, the identification signal may disadvantageously be stolen easily.
  • the identification signal is transmitted by using the infrared rays, it is possible to copy the identification signal easily by a so-called learning remote controller, which has already been developed into a social problem.
  • a keyless entry system has been proposed in which a portable apparatus (key apparatus) transmits an encryption value to a main apparatus (lock apparatus) and the main apparatus determines whether or not an encryption value which it obtains by itself by calculation of a value signal coincides with the received encryption value (see Japanese laid-open patent publication No. 7-269196 and Japanese laid-open patent publication No. 7-274258).
  • the main apparatus determines whether or not the encryption value which it obtains by itself by calculation of the value signal coincides with the received encryption value, except when the portable apparatus (key apparatus) and the main apparatus (lock apparatus) are manufactured, it is impossible that, after the portable apparatus and the main apparatus are manufactured, a specific identification signal is registered in both of the key apparatus and the main apparatus by transmitting the same specific identification signal from the portable apparatus to the main apparatus.
  • an identification signal checking apparatus includes an apparatus to be detected having a first wireless transmitting and receiving unit, a first signal processing unit and a first memory unit for storing an identification signal and includes a detecting apparatus having a second wireless transmitting and receiving unit, a second signal processing unit, a second memory unit for storing an identification signal, and a communication permission signal generating means.
  • the detecting apparatus receives a response request signal from the apparatus to be detected, the detecting apparatus transmits a random number signal obtained from the random number generating unit.
  • the apparatus to be detected encrypts said identification signal stored in the first memory unit by using the random number signal and transmits the encrypted identification signal to the detecting apparatus.
  • the detecting apparatus decrypts the encrypted identification signal and checks whether or not the decrypted identification signal coincides with the identification signal stored in the second memory unit.
  • the detecting transmits the random number signal and the apparatus to be detected (key apparatus) encrypts the identification signal by using the random number signal and transmits it to the detecting apparatus. Therefore, since the identification signal transmitted from the apparatus to be detected to the detecting apparatus is the encrypted signal obtained by encryption employing the random number signal and hence is always an unique signal, the security is improved.
  • the detecting apparatus decrypts the encrypted identification signal, even if the apparatus to be detected and the detecting apparatus are separately manufactured and distributed on the market, when the detecting apparatus is built in a door or the like, the detecting apparatus (lock apparatus) decrypts the encrypted signal transmitted from the apparatus to be detected (key apparatus) to obtain the specific identification signal. If the identification signal obtained by decryption is registered in the detecting apparatus, then it is possible to register the same identification signal in both of the apparatus to be detected (key apparatus) and the detecting apparatus (lock apparatus) .
  • an identification signal checking apparatus and an identification signal checking method according to a first embodiment of the present invention will be described with reference to the accompanying drawings.
  • the identification signal checking apparatus and method are applied to a keyless entry system for opening and closing a door.
  • a portable key apparatus 1 (an apparatus to be detected) has a switch unit 2 for issuing commands to open and close a door, a signal processing circuit unit 3, an infrared-ray transmitting and receiving unit 4 for communicating with a lock apparatus 10 described later on, and a memory unit 5 for storing a specific (own) identification signal ID.
  • the signal processing circuit unit 3 is formed of a microcomputer. When the switch unit 2 issues a commend to open or close the door by operating a switch thereof, the signal processing circuit unit 3 generates a response request signal including a lock/unlock command signal and supplies this response request signal to the infrared-ray transmitting and receiving unit 4. The infrared-ray transmitting and receiving unit 4 transmits the response request signal to the lock apparatus 10.
  • the signal processing circuit unit 3 When the key apparatus 1 receives a random number signal X formed of 24 bits, for example, from the lock apparatus 10, the signal processing circuit unit 3 encrypts a specific identification signal ID of 24 bits, for example, stored in the memory unit 5 to convert it into a code signal of 24 bits, for example, in accordance with a predetermined function f(X, ID) by using the 24-bit random number signal X, for example. Then, the signal processing circuit unit 3 transmits the encrypted signal f(X, ID) to the lock apparatus 10.
  • This function f(X, ID) is defined as shown below, for example, such that if respective corresponding bits of the random number signal X and the identification signal ID have the same value of "1" or "0", then the value of a corresponding bit in the function f(X, ID) is set to "1" and if the respective corresponding bits have the values different from each other, then the value thereof in the function f(X, ID) is set to "0".
  • the infrared-ray transmitting and receiving unit 4 is arranged so as to carry out communication in accordance with a known base band system.
  • the base band system permits high-speed communication at a lower consumed power and simplifies a circuit arrangement as compared with other modulation systems such as an amplitude shift keying (ASK), a frequency shift keying (FSK) or the like.
  • ASK amplitude shift keying
  • FSK frequency shift keying
  • the lock apparatus 10 is provided at a predetermined position in association with the door.
  • the lock apparatus 10 has an infrared-ray transmitting and receiving unit 11 for communicating with the key apparatus 1, a signal processing circuit unit 12, a memory unit 13 for storing a specific (own) identification signal ID, a random number generating unit 14 for generating the random number signal X, and a drive unit 15 for controlling a door locking or unlocking operation based on a command signal from the signal processing circuit unit 12.
  • a binary counter for processing 24 bits for example, is employed as the random number generating unit 14.
  • This 24-bit binary counter carries out a count operation in accordance with a predetermined clock signal regardless of the communication.
  • the lock apparatus 10 receives the response request signal from the key apparatus 1, the operation of the 24-bit binary counter is stopped and then a count value of the binary counter at this time is read, thereby the 24-bit random number signal X, for example, being obtained.
  • the signal processing circuit unit 12 is formed of a microcomputer. When the lock apparatus 10 receives the response request signal from the key apparatus 1, the signal processing circuit unit 12 transmits the random number signal X generated by the random number generating unit 14 from the lock apparatus 10 to the key apparatus 1.
  • the signal processing circuit unit 12 decrypts the received encrypted signal f(X, ID) in accordance with a predetermined function f -1 ⁇ f(x, ID), X ⁇ by using the previously transmitted 24-bit random number signal X, for example, and checks whether or not the identification signal ID obtained by this decryption coincides with the specific (own) identification signal ID previously stored (registered) in the memory unit 13.
  • the signal processing circuit unit 12 supplies a locking/unlocking command signal based on a door opening/closing command included in the response request signal to the drive unit 15. Then, under the operation of the drive unit 15, the door is opened or closed.
  • the infrared-ray transmitting and receiving unit 11 is arranged similarly to the above-mentioned infrared-ray transmitting and receiving unit 4, and arranged so as to carry out communication in accordance with the known base band system.
  • batteries 6 and 16 are used for energizing the key apparatus 1 and the lock apparatus 10, respectively.
  • FIG. 2 is a flowchart therefor and with reference to FIGS. 3A to 3D which are timing charts therefor.
  • the same specific (own) identification signals ID e.g., the identification signals ID formed of codes of 24 bits, for example, are previously registered (stored) in the memory units 5 and 13.
  • step S1 of the flowchart shown in FIG. 2 the switch unit 2 of the key apparatus 1 is operated and the switch thereof is set in its on-state, thereby a command to open or close a door being issued.
  • step S2 as shown in FIG. 3A, for example, the key apparatus 1 transmits the response request signal including the door opening/closing command signal to the lock apparatus 10 for a period of 100 ms. Then, the processing proceeds to step S3.
  • step S3 the lock apparatus 10 receives the response request signal as shown in FIG. 3D. Then, the processing proceeds to step S4, wherein the lock apparatus 10 obtains the 24-bit random number signal X, for example, generated by the random number generating unit 14.
  • step S5 as shown in FIG. 3C, the lock apparatus 10 transmits the random number signal X to the key apparatus 1 for a period of 30 ms. Then, the processing proceeds to step S6.
  • step S6 the key apparatus 1 receives the random number signal X as shown in FIG. 3B. Then, the processing proceeds to step S7, wherein the key apparatus 1 encrypts the specific (own) identification signal ID registered in the memory unit 5 to convert it into the 24-bit code signal, in accordance with the predetermined function f(X, ID) by using the 24-bit random number signal X, for example, and obtains the encrypted signal f(X, ID). Then, the processing proceeds to step S8, wherein the key apparatus 1 transmits the encrypted signal f(X, ID) to the lock apparatus 10 during the period of 30 ms, for example, as shown in FIG. 3A. Then, the processing proceeds to step S9.
  • step S9 the lock apparatus 10 receives the encrypted signal f(X, ID) as shown in FIG. 3D. Then, the processing proceeds to step S10, wherein the lock apparatus 10 decrypts the received encrypted signal f(X, ID) in accordance with the predetermined function f -1 ⁇ f(x, ID), X ⁇ by using the previously transmitted random number signal X. Then, the processing proceeds to step S11, wherein the lock apparatus 10 checks whether or not the decrypted identification signal ID coincides with the specific (own) identification signal ID previously registered in the memory unit 13.
  • step S12 as a result of the check processing, if the decrypted identification signal ID coincides with the specific (own) identification signal ID previously registered (stored) in the memory unit 13, then, in accordance with the door opening or closing command signal of the response request signal, the signal processing circuit unit 12 supplies the unlocking or locking command signal to the drive unit 15 for carrying out the unlocking or locking operation of the door. Then, under the control of the drive unit 15, the door is opened or closed.
  • the lock apparatus 10 every time when the operation of opening or closing the door is attempted, the lock apparatus 10 generates the random number signal X and the key apparatus 1 encrypts the identification signal ID by using the random number signal X and transmits the encrypted signal f(X, ID) to the lock apparatus 10. Therefore, since the signals transmitted in this both-way communication are constantly different from each other, even if these communication signals are intercepted, the specific (own) identification signal ID is prevented from being stolen.
  • the possibility that the code signals coincide with each other by accident is constant, e.g., the possibility is constantly about one over 16.7 million in a case of the 24-bit code signal. Therefore, it is advantageously possible to realize the extremely high security with ease.
  • the lock apparatus 10 decrypts the encrypted identification signal f(X, ID), even if the key apparatus 1 and the lock apparatus 10 are separately manufactured and distributed on a market, when the lock apparatus 10 is built in a door or the like, the lock apparatus 10 decrypts the encrypted signal f(X, ID) transmitted from the key apparatus 1 to obtain the specific (own) identification signal ID. Therefore, if the identification signal ID obtained by decryption is registered in the memory unit 13 of the lock apparatus 10, then it is possible to register the same identification signal ID in both of the key apparatus 1 and the lock apparatus 10.
  • FIGS. 4 and 5 An identification signal checking apparatus according to a second embodiment of the present invention will be described with reference to FIGS. 4 and 5.
  • parts corresponding to those in FIG. 1 are marked with the same reference numerals and hence need not be described.
  • a nonvolatile memory unit 5 of a key apparatus 1 stores a plurality of, e.g., sixteen identification signals ID 1 , ID 2 , ..., ID 16 .
  • a signal processing circuit unit 3 of the key apparatus 1 determines which of random number signals X 1 , X 2 , ..., X 16 a random number signal formed of lower 4 bits of the 24 bits of the received random number signal X is, and, if the lower 4-bit random number signal is a random number signal X 1 , selects one of sixteen identification signals ID 1 , ID 2 , ..., ID 16 stored in the memory unit 5, e.g., the identification signal ID 1 in response to the random number signal X 1 .
  • the random number signals X 1 , X 2 ,..., X 16 formed of the lower 4 bits of the above 24-bit random number signal X respectively correspond to sixteen identification signals ID 1 , ID 2 , ..., ID 16 stored in the memory unit 5.
  • Table 2 lower 4-bit random number identification signal encrypted signal X 1 0000 ID 1 f(X, ID 1 )
  • each of the sixteen identification signals ID 1 , ID 2 , ..., ID 16 stored in the memory unit 5 is formed of 24 bits, for example.
  • the signal processing circuit unit 3 encrypts one of the identification signals ID 1 , ID 2 , ..., ID 16 selected as shown in Table 2 in response to the received one of the lower 4-bit random number signal X 1 , X 2 , ..., X 16 of the random number signal X by using the received random number signal X, and obtains one of the encrypted signals f(X, ID 1 ), f(X, ID 2 ), ..., f(X, ID 16 ) shown in Table 2.
  • the key apparatus 1 transmits the obtained one of the encrypted signals f(X, ID 1 ), f(X, ID 2 ), ..., f(X, ID 16 ) to the lock apparatus 10.
  • the same identification signals e.g., the sixteen identification signals ID 1 , ID 2 , ..., ID 16 stored in the memory unit 5 of the key apparatus 1 are also stored in the memory unit 13 of the lock apparatus 10 shown in FIG. 4.
  • the signal processing circuit unit 12 of the lock apparatus 10 stores the 24-bit random number signal X, for example, generated by the random number generating unit 14 and transmitted therefrom in response to the response request signal from the key apparatus 1, and selects one of, for example, the sixteen identification signals ID 1 , ID 2 , ..., ID 16 stored in the memory unit 13 similarly to the key apparatus 1 in response to the selected one of the lower 4-bit random number signals X 1 , X 2 , ..., X 16 of the random number signal X.
  • the identification signal selected by the key apparatus 1 in response to one of the lower 4-bit random number signal X 1 , X 2 , ..., X 16 of the random number signal X is set the same as the identification signal selected by the lock apparatus 10 in response to the same one of the lower 4-bit random number signal X 1 , X 2 , ..., X 16 of the random number signal X.
  • the lock apparatus 10 When the lock apparatus 10 receives from the key apparatus 1 one of the encrypted signals f(X, ID 1 ), f(X, ID 2 ), ..., f(X, ID 16 ) obtained by encrypting the selected one of the identification signals ID 1 , ID 2 , ..., ID 16 , e.g., the encrypted signal f(X, ID1) by using the random number signal X, the signal processing circuit unit 12 decrypts the encrypted signals f(X, ID 1 ) in accordance with a predetermined function f -1 ⁇ f(X, ID 1 ), X ⁇ by using the identification signal ID 1 selected in response to the random number signal X 1 , for example, selected from the lower 4-bit random number signals X 1 , X 2 ,..., X 16 of the random number signal X, and checks whether or not the identification signal ID 1 obtained by the decryption coincides with the one of the identification signals ID 1 , ID 2 ,..., ID 16 previously selected in response to the lower 4-bit random
  • FIG. 5 is a flowchart therefor.
  • the same sixteen identification signals ID 1 , ID 2 , ..., ID 16 formed of codes of 24 bits, for example, are previously stored (registered) in both of the memory units 5 and 13.
  • step S21 of the flowchart shown in FIG. 5 the switch unit 2 of the key apparatus 1 is operated, thereby a command to open or close a door being issued.
  • step S22 as shown in FIG. 3A, for example, the key apparatus 1 transmits the response request signal including the door opening/closing command signal to the lock apparatus 10 for a period of 100 ms. Then the processing proceeds to step S23.
  • step S23 the lock apparatus 10 receives the response request signal as shown in FIG. 3D. Then, the processing proceeds to step S24, wherein the lock apparatus 10 obtains the 24-bit random number signal X, for example, generated by the random number generating unit 14.
  • step S25 as shown in FIG. 3C, the lock apparatus 10 transmits the random number signal X to the key apparatus 1 for the period of 30 ms, for example. Then, the processing proceeds to step S26.
  • step S26 the key apparatus 1 receives the random number signal X as shown in FIG. 3B. Then, the processing proceeds to step S27, wherein the key apparatus 1 selects one of the sixteen identification signals ID 1 , ID 2 , ..., ID 16 registered in the memory unit 5, e.g., the identification signal ID 1 in response to one of the lower 4-bit random number signals X 1 , X 2 , ..., X 16 of the random number signal X. Then, the processing proceeds to step S28.
  • step S28 the key apparatus 1 encrypts the selected identification signal ID 1 to convert it into the 24-bit code signal, in accordance with a predetermined function f(X, ID 1 ) by using the 24-bit random number signal X, for example, and then obtains the encrypted signal f(X, ID 1 ). Then, the processing proceeds to step S29, wherein the key apparatus 1 transmits the encrypted signal f(X, ID 1 ) to the lock apparatus 10 during the period of 30 ms, for example, as shown in FIG. 3A. Then, the processing proceeds to step S30.
  • step S30 the lock apparatus 10 receives the encrypted signal f(X, ID 1 ) as shown in FIG. 3D. Then, the processing proceeds to step S31, wherein the lock apparatus 10 decrypts the received encrypted signal f(X, ID 1 ) in accordance with a predetermined function f -1 ⁇ f(X, ID 1 ), X ⁇ by using the previously transmitted random number signal X. Then, the processing proceeds to step S32.
  • step S32 the lock apparatus 10 checks whether or not the decrypted identification signal ID 1 coincides with the one of the sixteen identification signals ID 1 , ID 2 , ..., ID 16 registered in the memory unit 13, e.g., the identification signal ID 1 selected in response to the selected one of the lower 4-bit random number signals X 1 , X 2 , ..., X 16 of the random number signal X.
  • step S33 as a result of the check processing, if the decrypted identification signal ID 1 coincides with the selected identification signal ID 1 , then, in accordance with the door opening or closing command signal of the response request signal, the signal processing circuit unit 12 supplies the unlocking or locking command signal to the drive unit 15 for carrying out the unlocking or locking operation of the door. Under the control of the drive unit 15, the door is opened or closed.
  • the identification signal checking apparatus according to the second embodiment shown in FIG. 4 is arranged as described above, it can easily be understood that it is possible to achieve the same effect as that of the identification signal checking apparatus according to the embodiment shown in FIG. 1.
  • the second embodiment shown in FIG. 4 since one of the sixteen identification signals ID 1 , ID 2 , ..., ID 16 is selected in response to one of the lower 4-bit random number signals X1, X 2 , ..., X 16 of the random number signal X, it is advantageously possible to improve the security further.
  • FIGS. 6 and 7 The identification signal checking apparatus according to a third embodiment of the present invention will be described with reference to FIGS. 6 and 7.
  • parts and units corresponding to those in FIG. 1 are marked with the same reference numerals and hence need not to be described in detail.
  • a nonvolatile memory unit 5 of a portable key apparatus 1 stores a specific (own) identification signal ID and a plurality of, e.g., sixteen functions f 1 , f 2 ,..., f 16 .
  • a signal processing circuit unit 3 of the key apparatus 1 determines which of random number signals X 1 , X 2 ,..., X 16 a random number signal formed of lower 4 bits of the 24 bits of the received random number signal X is, and, if the lower 4-bit random number signal is a random number signal X 1 , for example, selects one of sixteen functions f 1 , f 2 ,..., F 16 stored in a memory unit 5, e.g., the function f 1 in response to the random number signal X 1 .
  • the random number signals X 1 , X 2 ,..., X 16 formed of the lower 4 bits of the above 24-bit random number signal X respectively correspond to the sixteen functions f 1 , f 2 ,..., F 16 stored in the memory unit 5.
  • the identification signal ID stored in the memory unit 5 is formed of 24 bits, for example.
  • the signal processing circuit unit 3 encrypts the identification signal ID by using the received random number signal X and one of the functions f 1 , f 2 , ..., f 16 selected in response to one of the lower 4-bit random number signal X 1 , X 2 , ..., X 16 of the random number signal X, and obtains one of the encrypted signals f 1 (X, ID), f 2 (X, ID),..., f 16 (X, ID) shown in Table 3.
  • the key apparatus 1 transmits the obtained one of the encrypted signals f 1 (X, ID), f 2 (X, ID), ..., f16(X, ID) to the lock apparatus 10.
  • the same identification signal and the same plurality of, e.g., sixteen functions f 1 , f 2 ,..., f 16 stored in the memory unit 5 of the key apparatus 1 are also stored in the memory unit 13 of the lock apparatus 10 shown in FIG. 6.
  • the signal processing circuit unit 12 of the lock apparatus 10 stores the 24-bit random number signal X, for example, generated by the random number generating unit 14 and transmitted therefrom in response to the response request signal from the key apparatus 1, and selects one of, for example, the sixteen functions f 1 , f 2 , ..., f 16 stored in the memory unit 13 similarly to the key apparatus 1 in response to the received one of the lower 4-bit random number signals X 1 , X 2 , ..., X 16 of the random number signal X.
  • one of the functions f 1 , f 2 ,..., f 16 selected by the key apparatus 1 in response to one of the lower 4-bit random number signal X 1 , X 2 , ..., X 16 of the random number signal X is set the same as one of the functions f 1 , f 2 ,..., f 16 selected by the lock apparatus 10 in response to one of the lower 4-bit random number signals X 1 , X 2 ,..., X 16 of the random number signal X.
  • the lock apparatus 10 When the lock apparatus 10 receives from the key apparatus 1 one of the encrypted signals f 1 (X, ID), f 2 (X, ID, ..., f 16 (X, ID) obtained by encrypting the identification signal ID by using the selected one of the functions f 1 , f 2 ,..., f 16 and the random number signal X, e.g., the encrypted signal f 1 (X, ID), the signal processing circuit unit 12 decrypts the encrypted signals f1(X, ID) in accordance with a predetermined function f 1 -1 ⁇ f 1 (X, ID), X ⁇ by using the previously transmitted 24-bit random number signal X and the function f 1 selected in response to one of the lower 4-bit random number signals X 1 , X 2 , ..., X 16 of the random number signal X, e.g., selected in response to the random number signal X 1 , and checks whether or not the identification signal ID obtained by the decryption coincides with the identification signal ID previously registered in the memory
  • FIG. 7 is a flowchart therefor.
  • the identification signal and the sixteen functions f 1 , f 2 , ..., f 16 are previously registered (stored) in both of the memory units 5 and 13.
  • step S41 of the flowchart shown in FIG. 7 the switch unit 2 of the key apparatus 1 is operated, thereby a command to open or close a door being issued.
  • step S42 as shown in FIG. 3A, for example, the key apparatus 1 transmits the response request signal including the door opening/closing command signal to the lock apparatus 10 for a period of 100 ms. Then, the processing proceeds to step S43.
  • step S43 the lock apparatus 10 receives the response request signal as shown in FIG. 3D. Then, the processing proceeds to step S44, wherein the lock apparatus 10 obtains the 24-bit random number signal X, for example, generated by the random number generating unit 14.
  • step S45 as shown in FIG. 3C, the lock apparatus 10 transmits the random number signal X to the key apparatus 1 for a period of 30 ms, for example. Then, the processing proceeds to step S46.
  • step S46 the key apparatus 1 receives the random number signal X as shown in FIG. 3B. Then, the processing proceeds to step S47, wherein the key apparatus 1 selects one of the sixteen functions f 1 , f 2 ,..., f 16 registered in the memory unit 5, e.g., the function f 1 in response to one of the lower 4-bit random number signals X 1 , X 2 , ..., X 16 of the random number signal X. Then, the processing proceeds to step S48.
  • step S48 the key apparatus 1 encrypts the identification signal ID to convert it into the 24-bit code signal, by using the selected function f1 and the 24-bit random number signal X, for example, and then obtains the encrypted signal f 1 (X, ID). Then, the processing proceeds to step S49, wherein the key apparatus 1 transmits the encrypted signal f 1 (X, ID) to the lock apparatus 10 during the period of 30 ms, for example, as shown in FIG. 3A. Then, the processing proceeds to step S50.
  • step S50 the lock apparatus 10 receives the encrypted signal f 1 (X, ID) as shown in FIG. 3D. Then, the processing proceeds to step S51, wherein the lock apparatus 10 decrypts the received encrypted signal f 1 (X, ID) in accordance with a predetermined function f 1 -1 ⁇ f 1 (X, ID), X ⁇ by using the previously transmitted random number signal X and the corresponding one of the random number signals X 1 , X 2 , ..., X 16 of the random number signal X. Then, the processing proceeds to step S52.
  • step S52 the lock apparatus 10 checks whether or not the decrypted identification signal ID coincides with the identification signal ID registered in the memory unit 13.
  • step S53 as a result of the check processing, if the decrypted identification signal ID coincides with the identification signal ID registered in the memory unit 13, then, in accordance with the door opening or closing command signal of the response request signal, the signal processing circuit unit 12 supplies the unlocking or locking command signal to the drive unit 15 for carrying out the unlocking or locking operation of the door. Under the control of the drive unit 15, the door is opened or closed .
  • the identification signal checking apparatus according to the third embodiment shown in FIG. 6 is arranged as described above, it can easily be understood that it is possible to achieve the same effect as that of the identification signal checking apparatus according to the first embodiment shown in FIG. 1.
  • the third embodiment shown in FIG. 6 since one of the sixteen functions f 1 , f 2 ,..., f 16 is selected in response to one of the lower 4-bit random number signals X 1 , X 2 , ...,X 16 of the random number signal X, it is advantageously possible to improve the security further.
  • the communication between the key apparatus 1 and the lock apparatus 10 is carried out in accordance with the base band system by using the infrared rays
  • the communication may be carried out in accordance with some other modulation systems such as the ASK, the FSK or the like by using the infrared rays. It is needless to say that the communication may be carried out by using a radio wave or a supersonic wave instead of the infrared rays.
  • each of the random number signal, the identification signal and the encrypted signal is formed of 24 bits. It is sufficient to determine the number of bits thereof in response to a required degree of the security.
  • the response request signal includes the locking or unlocking command signal
  • the locking or unlocking command signal may be added to the above encrypted signal or may be transmitted individually.
  • the number of the identification signals ID 1 , ID 2 , ..., ID 16 or the functions f 1 , f 2 ,..., f 16 is set to 16, it is not necessary to set the number to 16, and hence the number may be set to any value depending upon a desired degree of security.
  • one of the identification signals ID 1 , ID 2 , ..., ID 16 or one of the functions f 1 , f 2 , ..., f 16 is selected in response to one of the lower 4-bit random number signals X 1 , X 2 , ..., X 16 of the random number signal X, it is not necessary to use the lower 4 bits of the random number signal X and one of the identification signals ID 1 , ID 2 , ..., ID 16 or one of the functions f 1 , f 2 ,...,f 16 may be selected by using any bits of the random number signal X.
  • the detecting apparatus transmits the random number signal
  • the apparatus to be detected encrypts the identification signal by using the random number signal and transmits the encrypted identification signal to the detecting apparatus (lock apparatus). Therefore, since the identification signal transmitted from the apparatus to be detected (key apparatus) to the detecting apparatus (lock apparatus) is the encrypted signal obtained by encryption using the random number signal and hence is always a unique signal, the security is advantageously improved.

Abstract

An identification signal checking apparatus includes an apparatus (1) to be detected having a first wireless transmitting and receiving unit (4) , a first signal processing unit (3) and a first memory unit (5) for storing an identification signal. A detecting apparatus (10) has a second wireless transmitting and receiving unit (11), a second signal processing unit (12), a second memory unit (13) for storing an identification signal, and a random number generating unit (14). When the detecting apparatus (10) receives a response request signal from the apparatus (1) to be detected, the detecting apparatus (10) transmits a random number signal obtained from the random number generating unit (14). When receiving the random number signal, the apparatus (1) to be detected encrypts the identification signal stored in the first memory unit (5) by using the random number signal and transmits the encrypted identification signal to the detecting apparatus (10). The detecting apparatus (10) decrypts the encrypted identification signal and checks whether or not it coincides with the identification signal stored in the second memory unit (13).

Description

  • The present invention relates to identification signal checking apparatus and methods, such as those suitable for use in a keyless entry system.
  • A keyless entry system has been proposed. In this keyless entry system, infrared rays or radio waves are used to transmit an identification signal from a key apparatus side to a lock apparatus side for the locking or the unlocking thereof.
  • Such keyless entry system employs a one-way communication in which the key apparatus side constantly transmits the same identification signal. Therefore, when this communication is intercepted, the identification signal may disadvantageously be stolen easily.
  • Particularly when the identification signal is transmitted by using the infrared rays, it is possible to copy the identification signal easily by a so-called learning remote controller, which has already been developed into a social problem.
  • Moreover, since in the above keyless entry system it is possible to detect a specific identification signal by using each of various identification signals to detect whether or not the identification signal coincides with the specific identification signal, there is the critical disadvantage in security.
  • Therefore, a keyless entry system has been proposed in which a portable apparatus (key apparatus) transmits an encryption value to a main apparatus (lock apparatus) and the main apparatus determines whether or not an encryption value which it obtains by itself by calculation of a value signal coincides with the received encryption value (see Japanese laid-open patent publication No. 7-269196 and Japanese laid-open patent publication No. 7-274258).
  • In such proposed keyless entry system, since the main apparatus determines whether or not the encryption value which it obtains by itself by calculation of the value signal coincides with the received encryption value, the security is improved.
  • However, in the previously proposed keyless entry system with a satisfactory security, since the main apparatus determines whether or not the encryption value which it obtains by itself by calculation of the value signal coincides with the received encryption value, except when the portable apparatus (key apparatus) and the main apparatus (lock apparatus) are manufactured, it is impossible that, after the portable apparatus and the main apparatus are manufactured, a specific identification signal is registered in both of the key apparatus and the main apparatus by transmitting the same specific identification signal from the portable apparatus to the main apparatus.
  • Therefore, in such system, when the portable apparatus (key apparatus) and the main apparatus (lock apparatus) are manufactured, the same specific identification signal is registered in both of them. Therefore, it is necessary to manage both of the portable apparatus (key apparatus) and the main apparatus (lock apparatus) as a pair of objects to be managed until the lock apparatus is finally built in a door, for example. This necessity leads to the disadvantage in effective management and in physical distribution.
  • In view of such aspects, it is therefore an aim of the present invention to improve the security with a comparatively simple arrangement and to make it unnecessary to manage the key apparatus (apparatus to be detected) and the lock apparatus (detecting apparatus) as a pair of separate items to be managed.
  • According to an aspect of the present invention, an identification signal checking apparatus includes an apparatus to be detected having a first wireless transmitting and receiving unit, a first signal processing unit and a first memory unit for storing an identification signal and includes a detecting apparatus having a second wireless transmitting and receiving unit, a second signal processing unit, a second memory unit for storing an identification signal, and a communication permission signal generating means. When the detecting apparatus receives a response request signal from the apparatus to be detected, the detecting apparatus transmits a random number signal obtained from the random number generating unit. When receiving the random number signal, the apparatus to be detected encrypts said identification signal stored in the first memory unit by using the random number signal and transmits the encrypted identification signal to the detecting apparatus. The detecting apparatus decrypts the encrypted identification signal and checks whether or not the decrypted identification signal coincides with the identification signal stored in the second memory unit.
  • According to the present invention, the detecting (lock apparatus) transmits the random number signal and the apparatus to be detected (key apparatus) encrypts the identification signal by using the random number signal and transmits it to the detecting apparatus. Therefore, since the identification signal transmitted from the apparatus to be detected to the detecting apparatus is the encrypted signal obtained by encryption employing the random number signal and hence is always an unique signal, the security is improved.
  • According to the present invention, since the detecting apparatus decrypts the encrypted identification signal, even if the apparatus to be detected and the detecting apparatus are separately manufactured and distributed on the market, when the detecting apparatus is built in a door or the like, the detecting apparatus (lock apparatus) decrypts the encrypted signal transmitted from the apparatus to be detected (key apparatus) to obtain the specific identification signal. If the identification signal obtained by decryption is registered in the detecting apparatus, then it is possible to register the same identification signal in both of the apparatus to be detected (key apparatus) and the detecting apparatus (lock apparatus) .
  • The invention will now be described by way of example with reference to the accompanying drawings, throughout which like parts are referred to by like references, and in which:
    • FIG. 1 is a block diagram showing an arrangement of an identification signal checking apparatus according to a first embodiment of the present invention;
    • FIG. 2 is a flowchart used to explain an operation of the identification signal checking apparatus according to the first embodiment of the present invention;
    • FIGS. 3A to 3D are timing charts used to explain communication between a key apparatus and a lock apparatus according to the first embodiment of the present invention;
    • FIG. 4 is a block diagram showing an arrangement of an identification signal checking apparatus according to a second embodiment of the present invention;
    • FIG. 5 is a flowchart used to explain an operation of the identification signal checking apparatus according to the second embodiment of the present invention;
    • FIG. 6 is a block diagram showing an arrangement of an identification signal checking apparatus according to a third embodiment of the present invention; and
    • FIG. 7 is a flowchart used to explain an operation of the identification signal checking apparatus according to the third embodiment of the present invention.
  • An identification signal checking apparatus and an identification signal checking method according to a first embodiment of the present invention will be described with reference to the accompanying drawings. In this embodiment, the identification signal checking apparatus and method are applied to a keyless entry system for opening and closing a door.
  • As shown in FIG. 1, a portable key apparatus 1 (an apparatus to be detected) has a switch unit 2 for issuing commands to open and close a door, a signal processing circuit unit 3, an infrared-ray transmitting and receiving unit 4 for communicating with a lock apparatus 10 described later on, and a memory unit 5 for storing a specific (own) identification signal ID.
  • The signal processing circuit unit 3 is formed of a microcomputer. When the switch unit 2 issues a commend to open or close the door by operating a switch thereof, the signal processing circuit unit 3 generates a response request signal including a lock/unlock command signal and supplies this response request signal to the infrared-ray transmitting and receiving unit 4. The infrared-ray transmitting and receiving unit 4 transmits the response request signal to the lock apparatus 10.
  • When the key apparatus 1 receives a random number signal X formed of 24 bits, for example, from the lock apparatus 10, the signal processing circuit unit 3 encrypts a specific identification signal ID of 24 bits, for example, stored in the memory unit 5 to convert it into a code signal of 24 bits, for example, in accordance with a predetermined function f(X, ID) by using the 24-bit random number signal X, for example. Then, the signal processing circuit unit 3 transmits the encrypted signal f(X, ID) to the lock apparatus 10.
  • This function f(X, ID) is defined as shown below, for example, such that if respective corresponding bits of the random number signal X and the identification signal ID have the same value of "1" or "0", then the value of a corresponding bit in the function f(X, ID) is set to "1" and if the respective corresponding bits have the values different from each other, then the value thereof in the function f(X, ID) is set to "0". Table 1
    ID 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
    X 1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1
    f(X, ID) 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1 1
  • The infrared-ray transmitting and receiving unit 4 according to this embodiment is arranged so as to carry out communication in accordance with a known base band system. The base band system permits high-speed communication at a lower consumed power and simplifies a circuit arrangement as compared with other modulation systems such as an amplitude shift keying (ASK), a frequency shift keying (FSK) or the like.
  • The lock apparatus 10 is provided at a predetermined position in association with the door. The lock apparatus 10 has an infrared-ray transmitting and receiving unit 11 for communicating with the key apparatus 1, a signal processing circuit unit 12, a memory unit 13 for storing a specific (own) identification signal ID, a random number generating unit 14 for generating the random number signal X, and a drive unit 15 for controlling a door locking or unlocking operation based on a command signal from the signal processing circuit unit 12.
  • A binary counter for processing 24 bits, for example, is employed as the random number generating unit 14. This 24-bit binary counter carries out a count operation in accordance with a predetermined clock signal regardless of the communication. When the lock apparatus 10 receives the response request signal from the key apparatus 1, the operation of the 24-bit binary counter is stopped and then a count value of the binary counter at this time is read, thereby the 24-bit random number signal X, for example, being obtained.
  • The signal processing circuit unit 12 is formed of a microcomputer. When the lock apparatus 10 receives the response request signal from the key apparatus 1, the signal processing circuit unit 12 transmits the random number signal X generated by the random number generating unit 14 from the lock apparatus 10 to the key apparatus 1.
  • When the lock apparatus 10 receives from the key apparatus 1 the encrypted signal f(X, ID) obtained by encrypting the identification signal ID with the random number signal X, the signal processing circuit unit 12 decrypts the received encrypted signal f(X, ID) in accordance with a predetermined function f-1{f(x, ID), X} by using the previously transmitted 24-bit random number signal X, for example, and checks whether or not the identification signal ID obtained by this decryption coincides with the specific (own) identification signal ID previously stored (registered) in the memory unit 13.
  • As a result of the check processing, if the decrypted identification signal ID coincides with the identification signal ID previously stored (registered), then the signal processing circuit unit 12 supplies a locking/unlocking command signal based on a door opening/closing command included in the response request signal to the drive unit 15. Then, under the operation of the drive unit 15, the door is opened or closed.
  • The infrared-ray transmitting and receiving unit 11 according to this embodiment is arranged similarly to the above-mentioned infrared-ray transmitting and receiving unit 4, and arranged so as to carry out communication in accordance with the known base band system. In FIG. 1, batteries 6 and 16 are used for energizing the key apparatus 1 and the lock apparatus 10, respectively.
  • An operation of the keyless entry system for opening and closing a door according to this embodiment will be described with reference to FIG. 2 which is a flowchart therefor and with reference to FIGS. 3A to 3D which are timing charts therefor. In this embodiment, it is assumed that the same specific (own) identification signals ID, e.g., the identification signals ID formed of codes of 24 bits, for example, are previously registered (stored) in the memory units 5 and 13.
  • In step S1 of the flowchart shown in FIG. 2, the switch unit 2 of the key apparatus 1 is operated and the switch thereof is set in its on-state, thereby a command to open or close a door being issued. In step S2, as shown in FIG. 3A, for example, the key apparatus 1 transmits the response request signal including the door opening/closing command signal to the lock apparatus 10 for a period of 100 ms. Then, the processing proceeds to step S3.
  • In step S3, the lock apparatus 10 receives the response request signal as shown in FIG. 3D. Then, the processing proceeds to step S4, wherein the lock apparatus 10 obtains the 24-bit random number signal X, for example, generated by the random number generating unit 14. In step S5, as shown in FIG. 3C, the lock apparatus 10 transmits the random number signal X to the key apparatus 1 for a period of 30 ms. Then, the processing proceeds to step S6.
  • In step S6, the key apparatus 1 receives the random number signal X as shown in FIG. 3B. Then, the processing proceeds to step S7, wherein the key apparatus 1 encrypts the specific (own) identification signal ID registered in the memory unit 5 to convert it into the 24-bit code signal, in accordance with the predetermined function f(X, ID) by using the 24-bit random number signal X, for example, and obtains the encrypted signal f(X, ID). Then, the processing proceeds to step S8, wherein the key apparatus 1 transmits the encrypted signal f(X, ID) to the lock apparatus 10 during the period of 30 ms, for example, as shown in FIG. 3A. Then, the processing proceeds to step S9.
  • In step S9, the lock apparatus 10 receives the encrypted signal f(X, ID) as shown in FIG. 3D. Then, the processing proceeds to step S10, wherein the lock apparatus 10 decrypts the received encrypted signal f(X, ID) in accordance with the predetermined function f-1{f(x, ID), X} by using the previously transmitted random number signal X. Then, the processing proceeds to step S11, wherein the lock apparatus 10 checks whether or not the decrypted identification signal ID coincides with the specific (own) identification signal ID previously registered in the memory unit 13. In step S12, as a result of the check processing, if the decrypted identification signal ID coincides with the specific (own) identification signal ID previously registered (stored) in the memory unit 13, then, in accordance with the door opening or closing command signal of the response request signal, the signal processing circuit unit 12 supplies the unlocking or locking command signal to the drive unit 15 for carrying out the unlocking or locking operation of the door. Then, under the control of the drive unit 15, the door is opened or closed.
  • According to this embodiment, every time when the operation of opening or closing the door is attempted, the lock apparatus 10 generates the random number signal X and the key apparatus 1 encrypts the identification signal ID by using the random number signal X and transmits the encrypted signal f(X, ID) to the lock apparatus 10. Therefore, since the signals transmitted in this both-way communication are constantly different from each other, even if these communication signals are intercepted, the specific (own) identification signal ID is prevented from being stolen.
  • According to this embodiment, even if the operation of opening or closing the door is attempted any times, the possibility that the code signals coincide with each other by accident is constant, e.g., the possibility is constantly about one over 16.7 million in a case of the 24-bit code signal. Therefore, it is advantageously possible to realize the extremely high security with ease.
  • Since the lock apparatus 10 decrypts the encrypted identification signal f(X, ID), even if the key apparatus 1 and the lock apparatus 10 are separately manufactured and distributed on a market, when the lock apparatus 10 is built in a door or the like, the lock apparatus 10 decrypts the encrypted signal f(X, ID) transmitted from the key apparatus 1 to obtain the specific (own) identification signal ID. Therefore, if the identification signal ID obtained by decryption is registered in the memory unit 13 of the lock apparatus 10, then it is possible to register the same identification signal ID in both of the key apparatus 1 and the lock apparatus 10.
  • Therefore, according to the first embodiment, it is not necessary to manage both of the key apparatus 1 and the lock apparatus 10 as a pair of the objects to be managed, which leads to the advantages in effective management and physical distribution.
  • An identification signal checking apparatus according to a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. In FIG. 4, parts corresponding to those in FIG. 1 are marked with the same reference numerals and hence need not be described.
  • In the second embodiment, a nonvolatile memory unit 5 of a key apparatus 1 stores a plurality of, e.g., sixteen identification signals ID1, ID2, ..., ID16.
  • When a key apparatus 1 receives a random number signal X of 24 bits, for example, from a lock apparatus 10, a signal processing circuit unit 3 of the key apparatus 1 determines which of random number signals X1, X2, ..., X16 a random number signal formed of lower 4 bits of the 24 bits of the received random number signal X is, and, if the lower 4-bit random number signal is a random number signal X1, selects one of sixteen identification signals ID1, ID2, ..., ID16 stored in the memory unit 5, e.g., the identification signal ID1 in response to the random number signal X1.
  • In this embodiment, as shown in Table 2, the random number signals X1, X2,..., X16 formed of the lower 4 bits of the above 24-bit random number signal X respectively correspond to sixteen identification signals ID1, ID2, ..., ID16 stored in the memory unit 5. Table 2
    lower 4-bit random number identification signal encrypted signal
    X1 = 0000 ID1 f(X, ID1)
    X2 = 0001 ID2 f(X, ID2)
    : : :
    : : :
    X16 = 1111 ID16 f(X, ID16)
  • In this second embodiment, each of the sixteen identification signals ID1, ID2, ..., ID16 stored in the memory unit 5 is formed of 24 bits, for example.
  • In this second embodiment, the signal processing circuit unit 3 encrypts one of the identification signals ID1, ID2, ..., ID16 selected as shown in Table 2 in response to the received one of the lower 4-bit random number signal X1, X2, ..., X16 of the random number signal X by using the received random number signal X, and obtains one of the encrypted signals f(X, ID1), f(X, ID2), ..., f(X, ID16) shown in Table 2. The key apparatus 1 transmits the obtained one of the encrypted signals f(X, ID1), f(X, ID2), ..., f(X, ID16) to the lock apparatus 10.
  • The same identification signals, e.g., the sixteen identification signals ID1, ID2, ..., ID16 stored in the memory unit 5 of the key apparatus 1 are also stored in the memory unit 13 of the lock apparatus 10 shown in FIG. 4.
  • The signal processing circuit unit 12 of the lock apparatus 10 stores the 24-bit random number signal X, for example, generated by the random number generating unit 14 and transmitted therefrom in response to the response request signal from the key apparatus 1, and selects one of, for example, the sixteen identification signals ID1, ID2, ..., ID16 stored in the memory unit 13 similarly to the key apparatus 1 in response to the selected one of the lower 4-bit random number signals X1, X2, ..., X16 of the random number signal X.
  • In this case, the identification signal selected by the key apparatus 1 in response to one of the lower 4-bit random number signal X1, X2, ..., X16 of the random number signal X is set the same as the identification signal selected by the lock apparatus 10 in response to the same one of the lower 4-bit random number signal X1, X2, ..., X16 of the random number signal X.
  • When the lock apparatus 10 receives from the key apparatus 1 one of the encrypted signals f(X, ID1), f(X, ID2), ..., f(X, ID16) obtained by encrypting the selected one of the identification signals ID1, ID2, ..., ID16, e.g., the encrypted signal f(X, ID1) by using the random number signal X, the signal processing circuit unit 12 decrypts the encrypted signals f(X, ID1) in accordance with a predetermined function f-1{f(X, ID1), X} by using the identification signal ID1 selected in response to the random number signal X1, for example, selected from the lower 4-bit random number signals X1, X2,..., X16 of the random number signal X, and checks whether or not the identification signal ID1 obtained by the decryption coincides with the one of the identification signals ID1, ID2,..., ID16 previously selected in response to the lower 4-bit random number signals X1, X2, ..., X16 of the random number signal X, e.g., the identification signal ID1.
  • Other parts and units of the identification signal checking apparatus according to the second embodiment shown in FIG. 4 are arranged similarly to those of the identification signal checking apparatus according to the first embodiment shown in FIG. 1.
  • An operation of the keyless entry system for opening and closing a door according to the second embodiment shown in FIG. 4 will be described with reference to FIG. 5 which is a flowchart therefor. In this second embodiment, it is assumed that the same sixteen identification signals ID1, ID2, ..., ID16 formed of codes of 24 bits, for example, are previously stored (registered) in both of the memory units 5 and 13.
  • In step S21 of the flowchart shown in FIG. 5, the switch unit 2 of the key apparatus 1 is operated, thereby a command to open or close a door being issued. In step S22, as shown in FIG. 3A, for example, the key apparatus 1 transmits the response request signal including the door opening/closing command signal to the lock apparatus 10 for a period of 100 ms. Then the processing proceeds to step S23.
  • In step S23, the lock apparatus 10 receives the response request signal as shown in FIG. 3D. Then, the processing proceeds to step S24, wherein the lock apparatus 10 obtains the 24-bit random number signal X, for example, generated by the random number generating unit 14. In step S25, as shown in FIG. 3C, the lock apparatus 10 transmits the random number signal X to the key apparatus 1 for the period of 30 ms, for example. Then, the processing proceeds to step S26.
  • In step S26, the key apparatus 1 receives the random number signal X as shown in FIG. 3B. Then, the processing proceeds to step S27, wherein the key apparatus 1 selects one of the sixteen identification signals ID1, ID2, ..., ID16 registered in the memory unit 5, e.g., the identification signal ID1 in response to one of the lower 4-bit random number signals X1, X2, ..., X16 of the random number signal X. Then, the processing proceeds to step S28.
  • In step S28, the key apparatus 1 encrypts the selected identification signal ID1 to convert it into the 24-bit code signal, in accordance with a predetermined function f(X, ID1) by using the 24-bit random number signal X, for example, and then obtains the encrypted signal f(X, ID1). Then, the processing proceeds to step S29, wherein the key apparatus 1 transmits the encrypted signal f(X, ID1) to the lock apparatus 10 during the period of 30 ms, for example, as shown in FIG. 3A. Then, the processing proceeds to step S30.
  • In step S30, the lock apparatus 10 receives the encrypted signal f(X, ID1) as shown in FIG. 3D. Then, the processing proceeds to step S31, wherein the lock apparatus 10 decrypts the received encrypted signal f(X, ID1) in accordance with a predetermined function f-1{f(X, ID1), X} by using the previously transmitted random number signal X. Then, the processing proceeds to step S32.
  • In step S32, the lock apparatus 10 checks whether or not the decrypted identification signal ID1 coincides with the one of the sixteen identification signals ID1, ID2, ..., ID16 registered in the memory unit 13, e.g., the identification signal ID1 selected in response to the selected one of the lower 4-bit random number signals X1, X2, ..., X16 of the random number signal X. In step S33, as a result of the check processing, if the decrypted identification signal ID1 coincides with the selected identification signal ID1, then, in accordance with the door opening or closing command signal of the response request signal, the signal processing circuit unit 12 supplies the unlocking or locking command signal to the drive unit 15 for carrying out the unlocking or locking operation of the door. Under the control of the drive unit 15, the door is opened or closed.
  • Since the identification signal checking apparatus according to the second embodiment shown in FIG. 4 is arranged as described above, it can easily be understood that it is possible to achieve the same effect as that of the identification signal checking apparatus according to the embodiment shown in FIG. 1. According to the second embodiment shown in FIG. 4, since one of the sixteen identification signals ID1, ID2, ..., ID16 is selected in response to one of the lower 4-bit random number signals X1, X2, ..., X16 of the random number signal X, it is advantageously possible to improve the security further.
  • The identification signal checking apparatus according to a third embodiment of the present invention will be described with reference to FIGS. 6 and 7. In FIG. 6, parts and units corresponding to those in FIG. 1 are marked with the same reference numerals and hence need not to be described in detail.
  • In the third embodiment shown in FIG. 6, a nonvolatile memory unit 5 of a portable key apparatus 1 stores a specific (own) identification signal ID and a plurality of, e.g., sixteen functions f1, f2,..., f16.
  • When the key apparatus 1 receives a random number signal X of 24 bits, for example, from a lock apparatus 10, a signal processing circuit unit 3 of the key apparatus 1 determines which of random number signals X1, X2,..., X16 a random number signal formed of lower 4 bits of the 24 bits of the received random number signal X is, and, if the lower 4-bit random number signal is a random number signal X1, for example, selects one of sixteen functions f1, f2,..., F16 stored in a memory unit 5, e.g., the function f1 in response to the random number signal X1.
  • In this third embodiment, as shown in Table 3, the random number signals X1, X2,..., X16 formed of the lower 4 bits of the above 24-bit random number signal X respectively correspond to the sixteen functions f1, f2,..., F16 stored in the memory unit 5.
    Figure imgb0001
    Figure imgb0002
  • In this third embodiment, the identification signal ID stored in the memory unit 5 is formed of 24 bits, for example.
  • In this embodiment, the signal processing circuit unit 3 encrypts the identification signal ID by using the received random number signal X and one of the functions f1, f2, ..., f16 selected in response to one of the lower 4-bit random number signal X1, X2, ..., X16 of the random number signal X, and obtains one of the encrypted signals f1(X, ID), f2(X, ID),..., f16(X, ID) shown in Table 3. The key apparatus 1 transmits the obtained one of the encrypted signals f1(X, ID), f2(X, ID), ..., f16(X, ID) to the lock apparatus 10.
  • The same identification signal and the same plurality of, e.g., sixteen functions f1, f2,..., f16 stored in the memory unit 5 of the key apparatus 1 are also stored in the memory unit 13 of the lock apparatus 10 shown in FIG. 6.
  • The signal processing circuit unit 12 of the lock apparatus 10 stores the 24-bit random number signal X, for example, generated by the random number generating unit 14 and transmitted therefrom in response to the response request signal from the key apparatus 1, and selects one of, for example, the sixteen functions f1, f2, ..., f16 stored in the memory unit 13 similarly to the key apparatus 1 in response to the received one of the lower 4-bit random number signals X1, X2, ..., X16 of the random number signal X.
  • In this case, one of the functions f1, f2,..., f16 selected by the key apparatus 1 in response to one of the lower 4-bit random number signal X1, X2, ..., X16 of the random number signal X is set the same as one of the functions f1, f2,..., f16 selected by the lock apparatus 10 in response to one of the lower 4-bit random number signals X1, X2,..., X16 of the random number signal X.
  • When the lock apparatus 10 receives from the key apparatus 1 one of the encrypted signals f1(X, ID), f2(X, ID, ..., f16(X, ID) obtained by encrypting the identification signal ID by using the selected one of the functions f1, f2,..., f16 and the random number signal X, e.g., the encrypted signal f1(X, ID), the signal processing circuit unit 12 decrypts the encrypted signals f1(X, ID) in accordance with a predetermined function f1 -1{f1(X, ID), X} by using the previously transmitted 24-bit random number signal X and the function f1 selected in response to one of the lower 4-bit random number signals X1, X2, ..., X16 of the random number signal X, e.g., selected in response to the random number signal X1, and checks whether or not the identification signal ID obtained by the decryption coincides with the identification signal ID previously registered in the memory unit 13.
  • Other parts of the identification signal checking apparatus according to the third embodiment shown in FIG. 6 are arranged similarly to those of the identification signal checking apparatus according to the first embodiment shown in FIG. 1.
  • An operation of the keyless entry system for opening and closing a door according to the third embodiment shown in FIG. 6 will be described with reference to FIG. 7 which is a flowchart therefor. In this third embodiment, it is assumed that the identification signal and the sixteen functions f1, f2, ..., f16 are previously registered (stored) in both of the memory units 5 and 13.
  • In step S41 of the flowchart shown in FIG. 7, the switch unit 2 of the key apparatus 1 is operated, thereby a command to open or close a door being issued. In step S42, as shown in FIG. 3A, for example, the key apparatus 1 transmits the response request signal including the door opening/closing command signal to the lock apparatus 10 for a period of 100 ms. Then, the processing proceeds to step S43.
  • In step S43, the lock apparatus 10 receives the response request signal as shown in FIG. 3D. Then, the processing proceeds to step S44, wherein the lock apparatus 10 obtains the 24-bit random number signal X, for example, generated by the random number generating unit 14. In step S45, as shown in FIG. 3C, the lock apparatus 10 transmits the random number signal X to the key apparatus 1 for a period of 30 ms, for example. Then, the processing proceeds to step S46.
  • In step S46, the key apparatus 1 receives the random number signal X as shown in FIG. 3B. Then, the processing proceeds to step S47, wherein the key apparatus 1 selects one of the sixteen functions f1, f2,..., f16 registered in the memory unit 5, e.g., the function f1 in response to one of the lower 4-bit random number signals X1, X2, ..., X16 of the random number signal X. Then, the processing proceeds to step S48.
  • In step S48, the key apparatus 1 encrypts the identification signal ID to convert it into the 24-bit code signal, by using the selected function f1 and the 24-bit random number signal X, for example, and then obtains the encrypted signal f1(X, ID). Then, the processing proceeds to step S49, wherein the key apparatus 1 transmits the encrypted signal f1(X, ID) to the lock apparatus 10 during the period of 30 ms, for example, as shown in FIG. 3A. Then, the processing proceeds to step S50.
  • In step S50, the lock apparatus 10 receives the encrypted signal f1(X, ID) as shown in FIG. 3D. Then, the processing proceeds to step S51, wherein the lock apparatus 10 decrypts the received encrypted signal f1(X, ID) in accordance with a predetermined function f1 -1{f1(X, ID), X} by using the previously transmitted random number signal X and the corresponding one of the random number signals X1, X2, ..., X16 of the random number signal X. Then, the processing proceeds to step S52.
  • In step S52, the lock apparatus 10 checks whether or not the decrypted identification signal ID coincides with the identification signal ID registered in the memory unit 13. In step S53, as a result of the check processing, if the decrypted identification signal ID coincides with the identification signal ID registered in the memory unit 13, then, in accordance with the door opening or closing command signal of the response request signal, the signal processing circuit unit 12 supplies the unlocking or locking command signal to the drive unit 15 for carrying out the unlocking or locking operation of the door. Under the control of the drive unit 15, the door is opened or closed .
  • Since the identification signal checking apparatus according to the third embodiment shown in FIG. 6 is arranged as described above, it can easily be understood that it is possible to achieve the same effect as that of the identification signal checking apparatus according to the first embodiment shown in FIG. 1. According to the third embodiment shown in FIG. 6, since one of the sixteen functions f1, f2,..., f16 is selected in response to one of the lower 4-bit random number signals X1, X2, ...,X16 of the random number signal X, it is advantageously possible to improve the security further.
  • While in the first to third embodiments the communication between the key apparatus 1 and the lock apparatus 10 is carried out in accordance with the base band system by using the infrared rays, the communication may be carried out in accordance with some other modulation systems such as the ASK, the FSK or the like by using the infrared rays. It is needless to say that the communication may be carried out by using a radio wave or a supersonic wave instead of the infrared rays.
  • It is not necessary that each of the random number signal, the identification signal and the encrypted signal is formed of 24 bits. It is sufficient to determine the number of bits thereof in response to a required degree of the security.
  • While in the first to third embodiments the response request signal includes the locking or unlocking command signal, the locking or unlocking command signal may be added to the above encrypted signal or may be transmitted individually.
  • In the above embodiments, the number of the identification signals ID1, ID2, ..., ID16 or the functions f1, f2,..., f16 is set to 16, it is not necessary to set the number to 16, and hence the number may be set to any value depending upon a desired degree of security.
  • While in the above embodiments one of the identification signals ID1, ID2, ..., ID16 or one of the functions f1, f2, ..., f16 is selected in response to one of the lower 4-bit random number signals X1, X2, ..., X16 of the random number signal X, it is not necessary to use the lower 4 bits of the random number signal X and one of the identification signals ID1, ID2, ..., ID16 or one of the functions f1, f2,...,f16 may be selected by using any bits of the random number signal X.
  • According to the first to third embodiments of the present invention, the detecting apparatus (lock apparatus) transmits the random number signal, and the apparatus to be detected (key apparatus) encrypts the identification signal by using the random number signal and transmits the encrypted identification signal to the detecting apparatus (lock apparatus). Therefore, since the identification signal transmitted from the apparatus to be detected (key apparatus) to the detecting apparatus (lock apparatus) is the encrypted signal obtained by encryption using the random number signal and hence is always a unique signal, the security is advantageously improved.
  • According to the embodiments of the present invention, since it is not necessary to manage the apparatus to be detected (key apparatus) and the detecting apparatus (lock apparatus) as a pair of items or objects to be managed, this leads to advantages in effective management and physical distribution.
  • Having described preferred embodiments of the present invention with reference to the accompanying drawings, it is to be understood that the present invention is not limited to the above-mentioned embodiments and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the present invention as defined in the appended claims.

Claims (12)

  1. An identification signal checking apparatus comprising:
    an apparatus to be detected having a first wireless transmitting and receiving unit, a first signal processing unit and a first memory unit for storing an identification signal; and
    a detecting apparatus having a second wireless transmitting and receiving unit, a second signal processing unit, a second memory unit for storing an identification signal, and a random number generating unit, wherein when said detecting apparatus receives a response request signal from said apparatus to be detected, said detecting apparatus transmits a random number signal obtained from said random number generating unit, when receiving said random number signal, said apparatus to be detected encrypts said identification signal stored in said first memory unit by using said random number signal and transmits said encrypted identification signal to said detecting apparatus, and said detecting apparatus decrypts said encrypted identification signal and checks whether or not said decrypted identification signal coincides with the identification signal stored in said second memory unit.
  2. An identification signal checking apparatus according to claim 1, wherein in accordance with a predetermined function, said identification signal is encrypted by using said random number signal.
  3. An identification signal checking apparatus according to claim 2, wherein said identification signal is composed of plurality of identification signals each corresponding to plurality of random number signals, said identification signals being stored in both of said first memory unit and said second memory unit and said identification signals are encrypted by corresponding random number signals, respectively.
  4. An identification signal checking apparatus according to claim 2, wherein said function is composed of plurality of functions each corresponding to plurality of random number signals, and a function is used for encryption in response to the corresponding random number signal.
  5. An identification signal checking apparatus according to claim 1, wherein said first and second wireless transmitting and receiving units are respectively infrared-ray transmitting and receiving units.
  6. An identification signal checking method of an identification signal checking apparatus having an apparatus to be detected having a first wireless transmitting and receiving unit, a first signal processing unit and a first memory unit for storing an identification signal, and a detecting apparatus having a second wireless transmitting and receiving unit, a second signal processing unit, a second memory unit for storing an identification signal, and a random number generating unit, comprising the steps of:
    transmitting a response request signal from said apparatus to be detected;
    transmitting, when said detecting apparatus receives said response request signal from said apparatus to be detected, a random number signal obtained from said random number generating unit from said detecting apparatus;
    encrypting, when said apparatus to be detected receives said random number signal, said identification signal stored in said first memory unit of said apparatus to be detected by using said random number signal;
    transmitting said encrypted identification signal from said apparatus to be detected to said detecting apparatus; and
    decrypting said encrypted identification signal by said detecting apparatus to check whether or not said decrypted identification signal coincides with the identification signal stored in said second memory unit.
  7. An identification signal checking method according to claim 6, wherein in accordance with a predetermined function, said identification signal is encrypted by using said random number signal.
  8. An identification signal checking method according to claim 7, wherein said identification signal is composed of plurality of identification signals each corresponding to plurality of random number signals, said identification signals being stored in both of said first memory unit and said second memory unit and said identification signals are encrypted by corresponding random number signals, respectively.
  9. An identification signal checking method according to claim 7, wherein said function is composed of plurality of functions each corresponding to plurality of random number signals, and a function is used for encryption in response to the corresponding random number signal.
  10. An identification signal checking method according to claim 6, wherein said first and second wireless transmitting and receiving units are respectively infrared-ray transmitting and receiving units.
  11. An identification signal checking apparatus according to claim 1, wherein said apparatus to be detected is a key apparatus, said detecting apparatus is a lock apparatus, said lock apparatus is provided with a locking means and/or an unlocking means, said lock apparatus controls said locking means and/or said unlocking means based on a check output indicative of whether or not said decrypted identification signal coincides with the identification signal stored in said second memory unit.
  12. An identification signal checking method according to claim 6, wherein said apparatus to be detected is a key apparatus, said detecting apparatus is a lock apparatus, said lock apparatus is provided.with a locking means and/or an unlocking means, said lock apparatus controls said locking means and/or said unlocking means based on a check output indicative of whether or not said decrypted identification signal coincides with the identification signal stored in said second memory unit.
EP97303313A 1996-05-16 1997-05-15 Identification signal checking apparatus and methods Withdrawn EP0807733A3 (en)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP12186996 1996-05-16
JP121869/96 1996-05-16
JP12186996 1996-05-16
JP24355596 1996-09-13
JP243555/96 1996-09-13
JP24355596A JPH1030367A (en) 1996-05-16 1996-09-13 Identification signal checking device and identification signal checking method

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EP0807733A2 true EP0807733A2 (en) 1997-11-19
EP0807733A3 EP0807733A3 (en) 2000-12-06

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JP3386430B2 (en) * 2000-02-23 2003-03-17 株式会社鷹山 Key with authentication opening and closing function and IC card
FI114062B (en) 2001-06-08 2004-07-30 Nokia Corp Method for ensuring the security of the communication, the communication system and the communication device
JP5379435B2 (en) * 2008-09-29 2013-12-25 アズビル株式会社 Entrance / exit management system and method
EP2544153A1 (en) * 2011-07-04 2013-01-09 ZF Friedrichshafen AG Identification technique

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US4509093A (en) * 1982-07-09 1985-04-02 Hulsbeck & Furst Gmbh & Co. Kg Electronic locking device having key and lock parts interacting via electrical pulses
US4819267A (en) * 1984-02-22 1989-04-04 Thumbscan, Inc. Solid state key for controlling access to computer systems and to computer software and/or for secure communications
GB2192665A (en) * 1986-07-18 1988-01-20 Neiman Security Products Limit Control apparatus
EP0484686A2 (en) * 1990-11-05 1992-05-13 International Business Machines Corporation Secure communications system for remotely located computers
US5321753A (en) * 1991-07-08 1994-06-14 The United States Of America As Represented By The United States Department Of Energy Secure communication of static information by electronic means
US5506575A (en) * 1991-09-25 1996-04-09 Ormos; Zoltan S. Key-lock system and method using interchange of system-originated codes
US5355413A (en) * 1992-03-06 1994-10-11 Mitsubishi Denki Kabushiki Kaisha Authentication method performed between IC card and terminal unit and system therefor

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KR970078181A (en) 1997-12-12
EP0807733A3 (en) 2000-12-06

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