Title:
【発明の名称】疑似乱数を用いる伝送メッセージの暗号確認
Document Type and Number:
Japanese Patent JPH08512184
Kind Code:
A
Abstract:
An automobile door lock receiver module (30) and a plurality of keychain fob transmitter units (16) contain identification numbers, secret initial values, and secret feedback masks so as to authenticate encrypted messages from any of the assigned fobs, indicative of commands registered by closing switches on the fob. Each fob is synchronized with the receiving module by means of a truly random number concatenated with a secret initial value and encrypted, through a linear feedback shift register or other operations. A second secret initial value is encrypted and command bits are exclusive ORed into the low order bit positions; the two encrypted numbers are concatenated and encrypted to form a key word which is transmitted with the fob ID. Synchronization includes decrypting to recover the truly random number and the secret initial value concatenated therewith; the truly random number is compared with previously received random numbers in order to avoid copying of recently transmitted synchronization commands. Successive lock-related commands utilize the number encrypted from the truly random number and the second secret initial value as starting values, employing a pseudorandom number of encryption iterations. A half-second delay between responses mitigates gaining access through numerical trials. An authenticated panic alarm command operates the headlights and horn of the vehicle but does not alter the synchronization.
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Inventors:
Coopman, Philip J. Jr.
Finn, Alan Em.
Finn, Alan Em.
Application Number:
JP50364294A
Publication Date:
December 17, 1996
Filing Date:
June 30, 1994
Export Citation:
Assignee:
United Technologies Automotive, Incorporated
International Classes:
E05B49/00; E05B65/20; G09C1/00; H04L9/12; H04L9/20; H04L9/32; (IPC1-7): H04L9/20; E05B49/00; E05B65/20; G09C1/00; H04L9/32
Attorney, Agent or Firm:
Fujiya Shiga (1 person outside)