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Keyless motor vehicle entry and ignition system

  • US 5,937,065 A
  • Filed: 04/07/1997
  • Issued: 08/10/1999
  • Est. Priority Date: 04/07/1997
  • Status: Expired due to Term
First Claim
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1. A method for operating a keyless motor vehicle control system including a remote control for carrying by a user and a control circuit in the motor vehicle, said method comprising the steps of:

  • storing seed data in the control circuit;

    storing the seed data in the remote control;

    programming a first remote control identification into the remote control;

    storing the first remote control identification into the control circuit;

    in response to activation of the remote control by movement of the user, exchanging challenge data between the control circuit and the remote control;

    the control circuit executing an encryption algorithm which uses the seed data and the challenge data to produce a first answer;

    the remote control executing the encryption algorithm which uses the seed data and the challenge data to produce a second answer;

    the remote control transmitting the second answer to the control circuit;

    the control circuit comparing the first and second answers and producing a first indication when a match occurs;

    the remote control transmitting the first remote control identification to the control circuit;

    determining whether the first remote control identification received from the remote control matches a first remote control identification previously stored in the control circuit and if so producing a second indication; and

    in response to presence of both the first and second indications, activating a component of the motor vehicle to perform a defined function.

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