Initialization method for keyless entry system

• US 5,767,784 A
• Filed: 10/20/1995
• Issued: 06/16/1998
• Est. Priority Date: 06/10/1994
• Status: Expired due to Term

• Current Assignee: Quintras Foundation AG LLC (Intellectual Ventures LLC)
• Original Assignee: Delco Electronics Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Khamharn, Oddy N
• Primary Examiner(s): ZIMMERMAN, BRIAN A
• Application Number:
  US08/545,993
• Time in Patent Office: 970 Days
• Field of Search: 340/825.31, 340/825.34, 340/825.33, 340/825.3, 340/825.69, 380/23
• US Class Current: 340/5.23
• CPC Class Codes: G07C 2009/00222 by more than one push button
• CPC Class Codes: G07C 2009/0023 with encription of the transmittted data signal
• CPC Class Codes: G07C 2009/00253 dynamically, e.g. variable code - rolling code
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2009/00984 fob
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks
• CPC Class Codes: G07C 9/00817 where the code of the lock can be programmed
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 2209/84 Vehicles
• CPC Class Codes: H04L 9/12 Transmitting and receiving encryption devices synchronised or initially set up in a particular manner
• CPC Class Codes: H04L 9/3242 involving keyed hash functions, e.g. message authentication codes [MACs], CBC-MAC or HMAC

Abstract

A system for remotely controlling a desired door locking or other function in a vehicle or other protected environment has a transmitter and receiver for communicating a message including a sequence number, the code of a selected function to be performed and an authenticator. An algorithm in the transmitter and in the receiver has a cryptographic key and a seed code. Each algorithm generates the authenticator as a function of both the seed code and the function code; if the authenticators are equal, the message is valid. Upon each transmission the seed code is updated and the sequence number is incremented. The receiver updates its seed code according to the transmitted sequence number to keep the algorithms in synchronism. To initialize the receiver to recognize the transmitter IDs, the receiver is manually enabled for programming, a counter is set to zero, the ID is transmitted from each transmitter, each ID is stored in sequence, and the counter is incremented for each ID received. During access mode only IDs in locations corresponding to the count value and lower values are used for validation.

Claims

1. In a keyless entry system for performing any of several commanded functions in a protected environment and having a receiver and a plurality of remote transmitters, each transmitter having an ID and the receiver having a memory for storing a plurality of IDs, a method of operation for the receiver for recognizing and responding to at least one substitute transmitter ID in lieu of previously entered IDs comprising the steps of:

entering a program mode by manually enabling the receiver for initialization;

receiving a message from each substitute transmitter including its ID;

storing each received ID in the receiver memory thereby writing over any IDs previously stored in corresponding memory locations;

identifying the memory locations containing substitute transmitter IDs;

then when in an access mode, comparing the IDs of received messages to only those IDs in the identified memory locations to determine the existence of a match, whereby previously stored IDs in other memory locations are ignored; and

performing a commanded function contained in a received message only when a match results.

2. The method of operation as defined in claim 1 wherein:

the step of storing each received ID comprises writing each ID as received in a sequential memory location; and

the step of identifying the memory locations comprises

incrementing a counter for each received ID so that each memory location corresponds to a counter value, and

saving data identifying the counter values.

3. The method of operation as defined in claim 1 including:

setting a counter to zero upon initialization;

the step of storing each received ID comprises writing each ID as received in a sequential memory location;

the step of identifying the memory locations comprises

incrementing a counter for each received ID so that each memory location corresponds to a counter value, and

saving a final counter value; and

in an access mode, determining the identified memory locations by reference to the final counter value and to lesser counter values.